Use of a constrained tripolar acetabular liner to treat intraoperative instability and postoperative dislocation after total hip arthroplasty: a review of our experience.

PubMed

Callaghan, John J; O'Rourke, Michael R; Goetz, Devon D; Lewallen, David G; Johnston, Richard C; Capello, William N

2004-12-01

Constrained acetabular components have been used to treat certain cases of intraoperative instability and postoperative dislocation after total hip arthroplasty. We report our experience with a tripolar constrained component used in these situations since 1988. The outcomes of the cases where this component was used were analyzed for component failure, component loosening, and osteolysis. At average 10-year followup, for cases treated for intraoperative instability (2 cases) or postoperative dislocation (4 cases), the component failure rate was 6% (6 of 101 hips in 5 patients). For cases where the constrained liner was cemented into a fixed cementless acetabular shell, the failure rate was 7% (2 of 31 hips in 2 patients) at 3.9-year average followup. Use of a constrained liner was not associated with an increased osteolysis or aseptic loosening rate. This tripolar constrained acetabular liner provided total hip arthroplasty construct stability in most cases in which it was used for intraoperative instability or postoperative dislocation.

Cemented total hip replacement cable debris and acetabular construct durability.

PubMed

Altenburg, Aaron J; Callaghan, John J; Yehyawi, Tameem M; Pedersen, Douglas R; Liu, Steve S; Leinen, Jessica A; Dahl, Kevin A; Goetz, Devon D; Brown, Thomas D; Johnston, Richard C

2009-07-01

Third-body wear can adversely affect the outcome of total hip arthroplasty by causing increased polyethylene wear, osteolysis, and component loosening. We hypothesized that there would be greater generation and migration of metal debris to the bearing surfaces in hips in which cobalt-chromium cables were used to reattach the osteotomized greater trochanter when compared with hips in which stainless steel wires were used. Between June 1981 and December 1983, 196 consecutive total hip arthroplasties were performed with use of an Iowa stem and a titanium-backed cemented acetabular component, with cobalt-chromium cable trochanteric reattachment. After nineteen to twenty years of follow-up, the patients were evaluated with regard to the depth of head penetration into the polyethylene (as a surrogate for wear), osteolysis, loosening, and the need for revision. The results were compared with those for a series of 304 total hip arthroplasties that were performed by the same surgeon from January 1984 to December 1985 with use of the same components and the same surgical technique, but with stainless steel wire trochanteric reattachment. The two groups had a comparable nineteen to twenty-year follow-up. All living patients (fifty-nine hips in the cable group and ninety-two hips in the wire group) had minimum ten-year follow-up radiographs. The polyethylene wear rate was 0.101 mm/yr for the cable group and 0.082 mm/yr for the wire group (p = 0.039). For the living patients, the rate of revision of the acetabular component because of aseptic loosening was 37.3% (twenty-two hips) for the cable group and 20.7% (nineteen hips) for the wire group (p = 0.025). The rate of acetabular osteolysis was 44% (twenty-six hips) for the cable group and 26% (twenty-four hips) for the wire group (p = 0.022). Kaplan-Meier analysis with revision of the acetabular component because of aseptic loosening as the end point demonstrated survival rates of 73.7% +/- 9% and 83% +/- 7% for the cable and wire groups, respectively, at twenty years (p = 0.03). Because cable trochanteric attachment led to significantly greater polyethylene wear, osteolysis, acetabular loosening, and acetabular revision, presumably due to third-body metallic debris generation in this cemented total hip replacement construct, surgeons should be aware of the deleterious effects of third-body debris and avoid the use of potential debris generators in the total hip arthroplasty construct. If cable is used and fretting is recognized, especially with intra-articular migration of metallic material or nonunion of the greater trochanter, consideration should be given to cable removal.

Revision of cemented hip arthroplasty using a hydroxyapatite-ceramic-coated femoral component.

PubMed

Raman, R; Kamath, R P; Parikh, A; Angus, P D

2005-08-01

We report the clinical and radiological outcome of 86 revisions of cemented hip arthroplasties using JRI-Furlong hydroxyapatite-ceramic-coated acetabular and femoral components. The acetabular component was revised in 62 hips and the femoral component in all hips. The mean follow-up was 12.6 years and no patient was lost to follow-up. The mean age of the patients was 71.2 years. The mean Harris hip and Oxford scores were 82 (59 to 96) and 23.4 (14 to 40), respectively. The mean Charnley modification of the Merle d'Aubigné and Postel score was 5 (3 to 6) for pain, 4.9 (3 to 6) for movement and 4.4 (3 to 6) for mobility. Migration of the acetabular component was seen in two hips and the mean acetabular inclination was 42.6 degrees. The mean linear polyethylene wear was 0.05 mm/year. The mean subsidence of the femoral component was 1.9 mm and stress shielding was seen in 23 (28%) with bony ingrowth in 76 (94%). Heterotopic ossification was seen in 12 hips (15%). There were three re-revisions, two for deep sepsis and one for recurrent dislocation and there were no re-revisions for aseptic loosening. The mean EuroQol EQ-5D description scores and health thermometer scores were 0.69 (0.51 to 0.89) and 79 (54 to 95), respectively. With an end-point of definite or probable loosening, the probability of survival at 12 years was 93.9% and 95.6% for the acetabular and femoral components, respectively. Overall survival at 12 years, with removal or further revision of either component for any reason as the end-point, was 92.3%. Our study supports the continued use of this arthroplasty and documents the durability of hydroxyapatite-ceramic-coated components.

The principle of low frictional torque in the Charnley total hip replacement.

PubMed

Wroblewski, B M; Siney, P D; Fleming, P A

2009-07-01

The design of the Charnley total hip replacement follows the principle of low frictional torque. It is based on the largest possible difference between the radius of the femoral head and that of the outer aspect of the acetabular component. The aim is to protect the bone-cement interface by movement taking place at the smaller radius, the articulation. This is achieved in clinical practice by a 22.225 mm diameter head articulating with a 40 mm or 43 mm diameter acetabular component of ultra-high molecular weight polyethylene. We compared the incidence of aseptic loosening of acetabular components with an outer diameter of 40 mm and 43 mm at comparable depths of penetration with a mean follow-up of 17 years (1 to 40). In cases with no measurable wear none of the acetabular components were loose. With increasing acetabular penetration there was an increased incidence of aseptic loosening which reflected the difference in the external radii, with 1.5% at 1 mm, 8.8% at 2 mm, 9.7% at 3 mm and 9.6% at 4 mm of penetration in favour of the larger 43 mm acetabular component. Our findings support the Charnley principle of low frictional torque. The level of the benefit is in keeping with the predicted values.

A cemented cup with acetabular impaction bone grafting is more cost-effective than an uncemented cup in patients under 50 years.

PubMed

Busch, Vincent J J F; Verschueren, Joost; Adang, Eddy M; Lie, Stein A; Havelin, Leif I; Schreurs, Berend W

2016-01-01

Acetabular deficiencies in young patients can be restored in several ways during total hip arthroplasty. Currently, cementless cups are most frequently used. Impaction bone grafting of acetabular defects is a more biological approach, but is it cost-effective in young patients on the long term? We designed a decision model for a cost-utility analysis of a cemented cup with acetabular impaction bone grafting versus an uncemented cup, in terms of cost per quality-adjusted life year (QALY) for the young adult with acetabular bone deficiency, in need for a primary total hip arthroplasty. Outcome probabilities and effectiveness were derived from the Radboud University Nijmegen Medical Centre and the Norwegian Hip Register. Multiple sensitivity analyses were used to assess the contribution of the included variables in the model's outcome. Cemented cups with impaction bone grafting were more cost-effective compared to the uncemented option in terms of costs per QALY. A scenario suggesting equal primary survival rates of both cemented and uncemented cups still showed an effect gain of the cemented cup with impaction bone grafting, but at higher costs. Based on this model, the first choice of treatment of the acetabular bone deficient osteoarthritic hip in a young patient is reconstruction with impaction bone grafting and a cemented cup.

21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a snap-fit acetabular component made of an alloy, such as cobalt-chromium-molybdenum, and ultra-high...

21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a snap-fit acetabular component made of an alloy, such as cobalt-chromium-molybdenum, and ultra-high...

21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a snap-fit acetabular component made of an alloy, such as cobalt-chromium-molybdenum, and ultra-high...

Acetabular revision with impaction bone grafting and a cemented polyethylene acetabular component: comparison of the Kaplan-Meier analysis to the competing risk analysis in 62 revisions with 25 to 30 years follow-up.

PubMed

Te Stroet, M A J; Keurentjes, J C; Rijnen, W H C; Gardeniers, J W M; Verdonschot, N; Slooff, T J J H; Schreurs, B W

2015-10-01

We present the results of 62 consecutive acetabular revisions using impaction bone grafting and a cemented polyethylene acetabular component in 58 patients (13 men and 45 women) after a mean follow-up of 27 years (25 to 30). All patients were prospectively followed. The mean age at revision was 59.2 years (23 to 82). We performed Kaplan-Meier (KM) analysis and also a Competing Risk (CR) analysis because with long-term follow-up, the presence of a competing event (i.e. death) prevents the occurrence of the endpoint of re-revision. A total of 48 patients (52 hips) had died or had been re-revised at final review in March 2011. None of the deaths were related to the surgery. The mean Harris hip score of the ten surviving hips in ten patients was 76 points (45 to 99). The KM survivorship at 25 years for the endpoint 're-revision for any reason' was 58.0% (95% confidence interval (CI) 38 to 73) and for 're-revision for aseptic loosening' 72.1% (95% CI 51 to 85). With the CR analysis we calculated the KM analysis overestimates the failure rate with respectively 74% and 93% for these endpoints. The current study shows that acetabular impaction bone grafting revisions provide good clinical results at over 25 years. ©2015 The British Editorial Society of Bone & Joint Surgery.

Cemented Total Hip Replacement Cable Debris and Acetabular Construct Durability

PubMed Central

Altenburg, Aaron J.; Callaghan, John J.; Yehyawi, Tameem M.; Pedersen, Douglas R.; Liu, Steve S.; Leinen, Jessica A.; Dahl, Kevin A.; Goetz, Devon D.; Brown, Thomas D.; Johnston, Richard C.

2009-01-01

Background: Third-body wear can adversely affect the outcome of total hip arthroplasty by causing increased polyethylene wear, osteolysis, and component loosening. We hypothesized that there would be greater generation and migration of metal debris to the bearing surfaces in hips in which cobalt-chromium cables were used to reattach the osteotomized greater trochanter when compared with hips in which stainless steel wires were used. Methods: Between June 1981 and December 1983, 196 consecutive total hip arthroplasties were performed with use of an Iowa stem and a titanium-backed cemented acetabular component, with cobalt-chromium cable trochanteric reattachment. After nineteen to twenty years of follow-up, the patients were evaluated with regard to the depth of head penetration into the polyethylene (as a surrogate for wear), osteolysis, loosening, and the need for revision. The results were compared with those for a series of 304 total hip arthroplasties that were performed by the same surgeon from January 1984 to December 1985 with use of the same components and the same surgical technique, but with stainless steel wire trochanteric reattachment. The two groups had a comparable nineteen to twenty-year follow-up. All living patients (fifty-nine hips in the cable group and ninety-two hips in the wire group) had minimum ten-year follow-up radiographs. Results: The polyethylene wear rate was 0.101 mm/yr for the cable group and 0.082 mm/yr for the wire group (p = 0.039). For the living patients, the rate of revision of the acetabular component because of aseptic loosening was 37.3% (twenty-two hips) for the cable group and 20.7% (nineteen hips) for the wire group (p = 0.025). The rate of acetabular osteolysis was 44% (twenty-six hips) for the cable group and 26% (twenty-four hips) for the wire group (p = 0.022). Kaplan-Meier analysis with revision of the acetabular component because of aseptic loosening as the end point demonstrated survival rates of 73.7% ± 9% and 83% ± 7% for the cable and wire groups, respectively, at twenty years (p = 0.03). Conclusions: Because cable trochanteric attachment led to significantly greater polyethylene wear, osteolysis, acetabular loosening, and acetabular revision, presumably due to third-body metallic debris generation in this cemented total hip replacement construct, surgeons should be aware of the deleterious effects of third-body debris and avoid the use of potential debris generators in the total hip arthroplasty construct. If cable is used and fretting is recognized, especially with intra-articular migration of metallic material or nonunion of the greater trochanter, consideration should be given to cable removal. Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence. PMID:19571089

The effect of cup outer sizes on the contact mechanics and cement fixation of cemented total hip replacements.

PubMed

Hua, Xijin; Li, Junyan; Wang, Ling; Wilcox, Ruth; Fisher, John; Jin, Zhongmin

2015-10-01

One important loosening mechanism of the cemented total hip arthroplasty is the mechanical overload at the bone-cement interface and consequent failure of the cement fixation. Clinical studies have revealed that the outer diameter of the acetabular component is a key factor in influencing aseptic loosening of the hip arthroplasty. The aim of the present study was to investigate the influence of the cup outer diameter on the contact mechanics and cement fixation of a cemented total hip replacement (THR) with different wear penetration depths and under different cup inclination angles using finite element (FE) method. A three-dimensional FE model was developed based on a typical Charnley hip prosthesis. Two acetabular cup designs with outer diameters of 40 and 43 mm were modelled and the effect of cup outer diameter, penetration depth and cup inclination angle on the contact mechanics and cement fixation stresses in the cemented THR were studied. The results showed that for all penetration depths and cup inclination angles considered, the contact mechanics in terms of peak von Mises stress in the acetabular cup and peak contact pressure at the bearing surface for the two cup designs were similar (within 5%). However, the peak von Mises stress, the peak maximum principal stress and peak shear stress in the cement mantle at the bone-cement interface for the 43 mm diameter cup design were predicted to be lower compared to those for the 40 mm diameter cup design. The differences were predicted to be 15-19%, 15-22% and 18-20% respectively for different cup penetration depths and inclination angles, which compares to the clinical difference of aseptic loosening incidence of about 20% between the two cup designs. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Novel cemented cup-holding technique while performing total hip arthroplasty with navigation system.

PubMed

Takai, Hirokazu; Takahashi, Tomoki

2017-09-01

Recently, navigation systems have been more widely utilized in total hip arthroplasty. However, almost all of these systems have been developed for cementless cups. In the case of cemented total hip arthroplasty using a navigation system, a special-ordered cemented holder is needed. We propose a novel cemented cup-holding technique for navigation systems using readily available articles. We combine a cementless cup holder with an inverted cementless trial cup. The resulting apparatus is used as a cemented cup holder. The upside-down cup-holding technique is useful and permits cemented cup users to utilize a navigation system for placement of the acetabular component.

Does a cemented cage improve revision THA for severe acetabular defects?

PubMed

Hansen, Erik; Shearer, David; Ries, Michael D

2011-02-01

Evidence suggests a growing incidence of revision total hip arthroplasty (THA) including a subset with large acetabular defects. Revision THA for severe acetabular bone loss is associated with a relatively high rate of mechanical failure. We questioned whether cementing a cage to the reconstructed acetabular defect and pelvis would improve the rate of mechanical failure for patients with Type 3 defects (Paprosky et al.) with and without pelvic discontinuity in comparison to historical controls. We retrospectively collected data on 33 patients who underwent 35 revision THAs using an acetabular reconstruction cage cemented to morselized allograft and either structural allograft or trabecular metal augmentation for Type 3 defects in the presence (n = 13) and absence (n = 22) of pelvic discontinuity at a mean followup of 59 months (range, 24-92 months). The primary outcome was mechanical failure, defined as revision of the acetabular reconstruction for aseptic loosening. Revision surgery for mechanical failure occurred in four of the 13 patients with pelvic discontinuity and two of the 22 patients without discontinuity. Radiographic loosening occurred in one patient with and one patient without pelvic discontinuity. Seven of the 35 revisions were subsequently revised for deep infection all in patients who were immunocompromised. Cementing the cage to the pelvis can offer an advantage for treating severe acetabular defects. Trabecular metal augmentation appears to provide better initial mechanical stability than a structural allograft, but successful allograft reconstruction may restore bone stock. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Early failure mechanisms of constrained tripolar acetabular sockets used in revision total hip arthroplasty.

PubMed

Cooke, Christopher C; Hozack, William; Lavernia, Carlos; Sharkey, Peter; Shastri, Shani; Rothman, Richard H

2003-10-01

Fifty-eight patients received an Osteonics constrained acetabular implant for recurrent instability (46), girdlestone reimplant (8), correction of leg lengthening (3), and periprosthetic fracture (1). The constrained liner was inserted into a cementless shell (49), cemented into a pre-existing cementless shell (6), cemented into a cage (2), and cemented directly into the acetabular bone (1). Eight patients (13.8%) required reoperation for failure of the constrained implant. Type I failure (bone-prosthesis interface) occurred in 3 cases. Two cementless shells became loose, and in 1 patient, the constrained liner was cemented into an acetabular cage, which then failed by pivoting laterally about the superior fixation screws. Type II failure (liner locking mechanism) occurred in 2 cases. Type III failure (femoral head locking mechanism) occurred in 3 patients. Seven of the 8 failures occurred in patients with recurrent instability. Constrained liners are an effective method for treatment during revision total hip arthroplasty but should be used in select cases only.

21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint (hemi-hip) acetabular metal cemented prosthesis. 888.3370 Section 888.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint...

21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint (hemi-hip) acetabular metal cemented prosthesis. 888.3370 Section 888.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint...

21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint (hemi-hip) acetabular metal cemented prosthesis. 888.3370 Section 888.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint...

Improving the accuracy of acetabular cup implantation using a bulls-eye spirit level.

PubMed

Macdonald, Duncan; Gupta, Sanjay; Ohly, Nicholas E; Patil, Sanjeev; Meek, R; Mohammed, Aslam

2011-01-01

Acetabular introducers have a built-in inclination of 45 degrees to the handle shaft. With patients in the lateral position, surgeons aim to align the introducer shaft vertical to the floor to implant the acetabulum at 45 degrees. We aimed to determine if a bulls-eye spirit level attached to an introducer improved the accuracy of implantation. A small circular bulls-eye spirit level was attached to the handle of an acetabular introducer. A saw bone hemipelvis was fixed to a horizontal, flat surface. A cement substitute was placed in the acetabulum and subjects were asked to implant a polyethylene cup, aiming to obtain an angle of inclination of 45 degrees. Two attempts were made with the spirit level masked and two with it unmasked. The distance of the air bubble from the spirit level's center was recorded by a single assessor. The angle of inclination of the acetabular component was then calculated. Subjects included both orthopedic consultants and trainees. Twenty-five subjects completed the study. Accuracy of acetabular implantation when using the unmasked spirit level improved significantly in all grades of surgeon. With the spirit level masked, 12 out of 50 attempts were accurate at 45 degrees inclination; 11 out of 50 attempts were "open," with greater than 45 degrees of inclination, and 27 were "closed," with less than 45 degrees. With the spirit level visible, all subjects achieved an inclination angle of exactly 45 degrees. A simple device attached to the handle of an acetabular introducer can significantly improve the accuracy of implantation of a cemented cup into a saw bone pelvis in the lateral position.

Single-stage Acetabular Revision During Two-stage THA Revision for Infection is Effective in Selected Patients.

PubMed

Fink, Bernd; Schlumberger, Michael; Oremek, Damian

2017-08-01

The treatment of periprosthetic infections of hip arthroplasties typically involves use of either a single- or two-stage (with implantation of a temporary spacer) revision surgery. In patients with severe acetabular bone deficiencies, either already present or after component removal, spacers cannot be safely implanted. In such hips where it is impossible to use spacers and yet a two-stage revision of the prosthetic stem is recommended, we have combined a two-stage revision of the stem with a single revision of the cup. To our knowledge, this approach has not been reported before. (1) What proportion of patients treated with single-stage acetabular reconstruction as part of a two-stage revision for an infected THA remain free from infection at 2 or more years? (2) What are the Harris hip scores after the first stage and at 2 years or more after the definitive reimplantation? Between June 2009 and June 2014, we treated all patients undergoing surgical treatment for an infected THA using a single-stage acetabular revision as part of a two-stage THA exchange if the acetabular defect classification was Paprosky Types 2B, 2C, 3A, 3B, or pelvic discontinuity and a two-stage procedure was preferred for the femur. The procedure included removal of all components, joint débridement, definitive acetabular reconstruction (with a cage to bridge the defect, and a cemented socket), and a temporary cemented femoral component at the first stage; the second stage consisted of repeat joint and femoral débridement and exchange of the femoral component to a cementless device. During the period noted, 35 patients met those definitions and were treated with this approach. No patients were lost to followup before 2 years; mean followup was 42 months (range, 24-84 months). The clinical evaluation was performed with the Harris hip scores and resolution of infection was assessed by the absence of clinical signs of infection and a C-reactive protein level less than 10 mg/L. All patients were assessed before surgery, between stages, every 3 months during the first year after surgery, every 6 months during the second year postoperative, and at latest followup, and were retrospectively drawn from a longitudinally maintained institutional database. Thirty-four of 35 patients (97.2%; 95% CI, 85.4%-99.5%) appeared free of infection by criteria of Masri et al. and Zimmerli et al. at latest followup. The Harris hip score was 61 ± 13 points after the first operation and 82 ± 16 points 2 years after the second operation. This technique is a promising treatment option for periprosthetic infections of the hip in which substantial acetabular defects exclude implantation of a normal spacer and a two-stage revision of the femoral component is favored. Level IV, therapeutic study.

Ten-Year Outcome of Serum Metal Ion Levels After Primary Total Hip Arthroplasty

PubMed Central

Levine, Brett R.; Hsu, Andrew R.; Skipor, Anastasia K.; Hallab, Nadim J.; Paprosky, Wayne G.; Galante, Jorge O.; Jacobs, Joshua J.

2013-01-01

Abstract: We previously reported on the metal ion concentrations of cobalt, chromium, and titanium that were found in the serum of patients three years after they had undergone primary total hip arthroplasty as compared with the concentrations found in the serum of control patients who did not have an implant. This study is a concise update on the serum metal levels found in a cohort of these patients ten years after the time of hip implantation. Of the original seventy-five subjects, metal ion levels were available for forty patients (53%). Ten patients (hybrid group) had received a hybrid total hip replacement that consisted of a modular cobalt-alloy femoral stem with a cobalt-alloy femoral head that had been inserted with cement and a titanium acetabular socket that had been inserted without cement. Nine patients (cobalt-chromium [CoCr] group) had received an implant with an extensively porous-coated modular cobalt-alloy femoral stem and femoral head along with a titanium acetabular socket; the femoral and acetabular components had each been inserted without cement. Eight patients (titanium group) had undergone insertion of a proximally porous-coated modular titanium-alloy femoral stem with a cobalt-alloy femoral head and a titanium acetabular socket; the femoral and acetabular components had each been inserted without cement. Thirteen patients (control group) from the original control group of patients who had not received an implant served as control subjects. Serum metal levels were measured with use of high-resolution sector field inductively coupled plasma mass spectrometry. The hybrid total hip arthroplasty group had mean cobalt levels that were 3.2 times higher at 120 months than they were at baseline, and the cobalt levels in that group were significantly higher than those in the titanium total hip arthroplasty group at thirty-six, sixty, eighty-four, ninety-six, and 120 months (p < 0.01). The hybrid group had mean chromium levels that were 3.9 times higher at 120 months than they were at baseline, and the CoCr total hip arthroplasty group had chromium levels that were 3.6 times higher at 120 months than they were at baseline. The serum titanium levels were higher in the titanium group at all follow-up time intervals as compared with the levels in all other groups, and the level in the titanium group at 120 months was eighteen times higher than it was at baseline (p < 0.01). Patients with well-functioning primary metal-on-polyethylene total hip replacements had elevated serum metal levels for as many as ten years postoperatively. Furthermore, metal release at the modular femoral head-neck junctions, rather than passive dissolution from porous ingrowth surfaces, was likely the dominant source of serum cobalt and chromium. Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence. PMID:23515985

Acetabular Cup Revision.

PubMed

Kim, Young-Ho

2017-09-01

The use of acetabular cup revision arthroplasty is on the rise as demands for total hip arthroplasty, improved life expectancies, and the need for individual activity increase. For an acetabular cup revision to be successful, the cup should gain stable fixation within the remaining supportive bone of the acetabulum. Since the patient's remaining supportive acetabular bone stock plays an important role in the success of revision, accurate classification of the degree of acetabular bone defect is necessary. The Paprosky classification system is most commonly used when determining the location and degree of acetabular bone loss. Common treatment options include: acetabular liner exchange, high hip center, oblong cup, trabecular metal cup with augment, bipolar cup, bulk structural graft, cemented cup, uncemented cup including jumbo cup, acetabular reinforcement device (cage), trabecular metal cup cage. The optimal treatment option is dependent upon the degree of the discontinuity, the amount of available bone stock and the likelihood of achieving stable fixation upon supportive host bone. To achieve successful acetabular cup revision, accurate evaluation of bone defect preoperatively and intraoperatively, proper choice of method of acetabular revision according to the evaluation of acetabular bone deficiency, proper technique to get primary stability of implant such as precise grafting technique, and stable fixation of implant are mandatory.

Combination acetabular radiofrequency ablation and cementoplasty using a navigational radiofrequency ablation device and ultrahigh viscosity cement: technical note.

PubMed

Wallace, Adam N; Huang, Ambrose J; Vaswani, Devin; Chang, Randy O; Jennings, Jack W

2016-03-01

Percutaneous radiofrequency ablation and cementoplasty is an alternative palliative therapy for painful metastases involving axial load-bearing bones. This technical report describes the use of a navigational radiofrequency probe to ablate acetabular metastases from an anterior approach followed by instillation of ultrahigh viscosity cement under CT-fluoroscopic guidance. The tumor ablation databases of two institutions were retrospectively reviewed to identify patients who underwent combination acetabular radiofrequency ablation and cementoplasty using the STAR Tumor Ablation and StabiliT Vertebral Augmentation Systems (DFINE; San Jose, CA). Pre-procedure acetabular tumor volume was measured on cross-sectional imaging. Pre- and post-procedure pain scores were measured using the Numeric Rating Scale (10-point scale) and compared. Partial pain improvement was categorically defined as ≥ 2-point pain score reduction. Patients were evaluated for evidence of immediate complications. Electronic medical records were reviewed for evidence of delayed complications. During the study period, 12 patients with acetabular metastases were treated. The median tumor volume was 54.3 mL (range, 28.3-109.8 mL). Pre- and post-procedure pain scores were obtained from 92% (11/12) of the cohort. The median pre-procedure pain score was 8 (range, 3-10). Post-procedure pain scores were obtained 7 days (82%; 9/11), 11 days (9.1%; 1/11) or 21 days (9.1%; 1/11) after treatment. The median post-treatment pain score was 3 (range, 1-8), a statistically significant difference compared with pre-treatment (P = 0.002). Categorically, 73% (8/11) of patients reported partial pain relief after treatment. No immediate symptomatic complications occurred. Three patients (25%; 3/12) were discharged to hospice within 1 week of treatment. No delayed complications occurred in the remaining 75% (9/12) of patients during median clinical follow-up of 62 days (range, 14-178 days). Palliative percutaneous acetabular radiofrequency ablation and cementoplasty can be feasibly performed from an anterior approach using a navigational ablation probe and ultrahigh viscosity cement instilled under CT-fluoroscopic guidance.

Long-term results with the Atlas IIIp elastic cementless acetabular component in total hip replacement.

PubMed

Lee, Paul Yuh Feng; Rachala, Madhu; Teoh, Kar Ho; Woodnutt, David John

2016-09-01

Modular cementless elastic acetabular systems have advantages over cemented and hard shell cementless acetabular systems. There are few reports on the medium-term and long-term follow up of this particular type of implant. This study describes our experience with the Atlas IIIp modular acetabular system, which is a thin shell cementless elastic acetabular implant for total hip replacement commercialized under this name in many countries. We prospectively followed 244 patients treated with Atlas IIIp acetabular system between 2001 and 2004. Minimum ten year follow up was available for 148 hips (139 patients) from the original cohort of 263 hips (244 patients). One hundred five patients had died from unrelated causes and were excluded from the results. Post-operative and follow up radiographs of patients were assessed; and Harris hip scores were used as clinical outcome. Revision for any reason was defined as the end point for survivorship analysis. The mean pre-operative Harris hip score was 48 (S.D. 16) and the average post-operative score was 82 (S.D. 12). The mean follow up in our series was 11.5 years, ranging from ten to 13.5 years. Thirteen hips required further surgery in our cohort; of which ten cases required cup revision. The 13-years cumulative implant survival was 91.2 % and the risk of implant revision was 8.8 % at 13 years in 148 hips (139 patients). Kaplan-Meier analysis showed the implant survival rate of 95.2 % at ten years for revision for any reason and 99.4 % for aseptic loosening. Our clinical experience with this acetabular cup suggests good long-term survival rates that are similar to other cups on the market. The clinical experience in this study shows long-term survival rates that are consistent, acceptable and good results achieved with a low revision rate. Therapeutic III; therapeutic study.

Preservation of the Acetabular Cup During Revision Total Hip Arthroplasty Using a Novel Mini-navigation Tool: A Case Report.

PubMed

Vincent, John; Alshaygy, Ibrahim; Muir, Jeffrey M; Kuzyk, Paul

2018-01-01

While intraoperative navigation systems have been shown to improve outcomes in primary total hip arthroplasty (THA), their use in the context of revision has been largely overlooked. This case report presents the first documented use of an imageless navigation tool in the context of revision THA, and an unexpected benefit to the surgical procedure as a result. An 84-year-old female patient presented following five episodes of dislocation of the left hip and with pain in the left buttock, groin, and posterior aspect of her hip. Relevant surgical history included primary hip arthroplasty in 1999 and the first revision in 2014. Preoperative analysis revealed a constrained liner that had become disengaged and migrated inferiorly, lodging at the distal aspect of the femoral neck. Acetabular protrusion was also noted. The pre-operative plan included the replacement of the fragmented liner and likely of the acetabular cup due to hardware failure. Intraoperative assessment, however, revealed that the cup was in good condition and would be difficult to remove due to substantial bony ingrowth. With the assistance of imageless navigation, the orientation of the acetabular cup was determined and a new constrained liner was cemented into the preexisting acetabular component at an altered orientation, correcting anteversion by 7°. In revision hip arthroplasty cases, image-based navigation is limited by the presence of existing implants and corresponding metal artefact. This case demonstrates the successful use of an imageless navigation tool for revision surgery. Use of navigation led to the unexpected intraoperative discovery that the acetabular cup was in an acceptable state, and allowed the surgical team to correct the position of the cup using a constrained liner, thus preserving the cup. This significantly benefitted patient outcome, due to the risks associated with the removal of a firmly fixated acetabular cup. While more extensive research is required, this case demonstrates that imageless navigation may be an indispensable tool for revision surgery.

Reconstruction of the Shallow Acetabulum With a Combination of Autologous Bulk and Impaction Bone Grafting Fixed by Cement.

PubMed

Maruyama, Masaaki; Wakabayashi, Shinji; Ota, Hiroshi; Tensho, Keiji

2017-02-01

Acetabular bone deficiency, especially proximal and lateral deficiency, is a difficult technical problem during primary total hip arthroplasty (THA) in developmental dysplasia of the hip (DDH). We report a new reconstruction method using a medial-reduced cemented socket and additional bulk bone in conjunction with impaction morselized bone grafting (additional bulk bone grafting method). In a population of patients with acetabular dysplasia undergoing THA using a medial-reduced cemented socket and additional bulk bone with impacted morselized bone grafting, we evaluated (1) the radiographic appearance of bone graft; (2) the proportion of cups that developed loosening and subsequent revision; and (3) clinical results (outcome scores and complications). Forty percent of 330 THAs for DDH performed at one center between 1999 and 2009 were defined as shallow dysplastic hips. The additional bulk bone grafting method was performed on 102 THAs with shallow acetabulum (31% for DDH) at one center between 1999 and 2009. We used this approach and technique for shallow acetabuli when a cup protruded from the lateral acetabular edge in preoperative templating. The other 132 dysplastic hips without bone grafting had THA performed at the same periods and served as a control. Acetabuli were defined as shallow when the depth was less than or equal to one-fifth of the pelvic height (cranial-caudal length on radiograph). The additional bulk bone grafting technique was as follows: the resected femoral head was sectioned at 1 to 2 cm thickness, and a suitable size of the bulk bone graft was placed on the lateral iliac cortex and fixed by poly-L-lactate absorbable screws. Autologous impaction morselized bone grafting, with or without hydroxyapatite granules, was performed along with the implantation of a medial-reduced cemented socket. We defined an "incorporated" graft as remodeling and trabeculation including rounding off of the protruding edge of a graft beyond the socket. Radiographic criteria used for determining loosening were migration or a continuous radiolucent zone between the prosthesis/bone cement and host bone. Clinical outcomes were assessed using the Japanese Orthopaedic Association (JOA) and the Merle d'Aubigne and Postel score; complications were tallied from chart review. The followup was 10 ± 3 years (range, 6-15 years). One acetabular component (1%) with severe shallow and steep acetabuli showed definite radiographic evidence of loosening and was revised. Clinically, the mean JOA score for the hips treated with additional bulk bone grafting THA in this study improved from 39 ± 10 points preoperatively to 95 ± 5 points postoperatively (p < 0.05, paired t-test). The mean Merle d'Aubigne and Postel score for the hips improved from 7 ± 2 points to 17 ± 1 points (p < 0.05, paired t-test). Complications included a Trendelenburg sign in one hip, dislocation in one, and transient partial sciatic nerve palsy in one. Within 3 years 6 months postoperatively, 101 of 102 additional bulk bone grafting cases showed successful bone remodeling and bone graft reorientation without collapse on radiographs. Partial resorption of the additional bone graft on the lateral side was observed in two hips (2%) with socket abduction angles of < 35°. Achieving stable acetabular fixation is often challenging in the dysplastic hip, especially shallow acetabulum, and a variety of techniques have been described. Early results of combining bulk graft with impaction of morselized graft are promising. Although each surgical technique was well established, further investigation for clinical results of a combination of these techniques might be necessary to confirm longer term outcomes. Level IV, therapeutic study.

Optimal acetabular component orientation estimated using edge-loading and impingement risk in patients with metal-on-metal hip resurfacing arthroplasty.

PubMed

Mellon, Stephen J; Grammatopoulos, George; Andersen, Michael S; Pandit, Hemant G; Gill, Harinderjit S; Murray, David W

2015-01-21

Edge-loading in patients with metal-on-metal resurfaced hips can cause high serum metal ion levels, the development of soft-tissue reactions local to the joint called pseudotumours and ultimately, failure of the implant. Primary edge-loading is where contact between the femoral and acetabular components occurs at the edge/rim of the acetabular component whereas impingement of the femoral neck on the acetabular component's edge causes secondary or contrecoup edge-loading. Although the relationship between the orientation of the acetabular component and primary edge-loading has been identified, the contribution of acetabular component orientation to impingement and secondary edge-loading is less clear. Our aim was to estimate the optimal acetabular component orientation for 16 metal-on-metal hip resurfacing arthroplasty (MoMHRA) subjects with known serum metal ion levels. Data from motion analysis, subject-specific musculoskeletal modelling and Computed Tomography (CT) measurements were used to calculate the dynamic contact patch to rim (CPR) distance and impingement risk for 3416 different acetabular component orientations during gait, sit-to-stand, stair descent and static standing. For each subject, safe zones free from impingement and edge-loading (CPR <10%) were defined and, consequently, an optimal acetabular component orientation was determined (mean inclination 39.7° (SD 6.6°) mean anteversion 14.9° (SD 9.0°)). The results of this study suggest that the optimal acetabular component orientation can be determined from a patient's motion and anatomy. However, 'safe' zones of acetabular component orientation associated with reduced risk of dislocation and pseudotumour are also associated with a reduced risk of edge-loading and impingement. Copyright © 2014 Elsevier Ltd. All rights reserved.

21 CFR 878.3300 - Surgical mesh.

Code of Federal Regulations, 2012 CFR

2012-04-01

... GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3300 Surgical mesh. (a) Identification... acetabular and cement restrictor mesh used during orthopedic surgery. (b) Classification. Class II. ...

21 CFR 878.3300 - Surgical mesh.

Code of Federal Regulations, 2014 CFR

2014-04-01

... GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3300 Surgical mesh. (a) Identification... acetabular and cement restrictor mesh used during orthopedic surgery. (b) Classification. Class II. ...

21 CFR 878.3300 - Surgical mesh.

Code of Federal Regulations, 2010 CFR

2010-04-01

... GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3300 Surgical mesh. (a) Identification... acetabular and cement restrictor mesh used during orthopedic surgery. (b) Classification. Class II. ...

21 CFR 878.3300 - Surgical mesh.

Code of Federal Regulations, 2013 CFR

2013-04-01

... GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3300 Surgical mesh. (a) Identification... acetabular and cement restrictor mesh used during orthopedic surgery. (b) Classification. Class II. ...

21 CFR 878.3300 - Surgical mesh.

Code of Federal Regulations, 2011 CFR

2011-04-01

... GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3300 Surgical mesh. (a) Identification... acetabular and cement restrictor mesh used during orthopedic surgery. (b) Classification. Class II. ...

Reduced survival for uncemented compared to cemented total hip arthroplasty after operatively treated acetabular fractures.

PubMed

Clarke-Jenssen, John; Westberg, Marianne; Røise, Olav; Storeggen, Stein Arne Øvre; Bere, Tone; Silberg, Ingunn; Madsen, Jan Erik

2017-11-01

Post traumatic arthritis and avascular necrosis of the femoral head are common complications after operatively treated acetabular fractures. This may cause severe disabilities for the patient, necessitating a total hip arthroplasty. Even though an arthroplasty may provide good symptomatic relief, the long-term results are more uncertain and no consensus exists according to preferred prosthetic designs. With this cohort study, we aimed to investigate the medium to long term arthroplasty survival and clinical results of total hip arthroplasty after operatively treated acetabular fractures. We included 52 patients treated with a secondary total hip arthroplasty at a median of 2.4 (0.1-14.1) years after an operatively treated acetabular fracture. The median age was 54 (11-82) years. Cemented arthroplasty was used for 33 patients, 10 patients had an uncemented arthroplasty and 9 patients received a hybrid arthroplasty. Average follow up was 8.0 (SD 5.0) years. Ten-year revision free arthroplasty survival was 79%. Uncemented arthroplasties had a significantly worse 10-year survival of 57%. Arthroplasties performed at a centre without a pelvic fracture service also had a significantly worse 10-years survival of 51%. Cox regression showed similar results with an 8-fold increase in risk of revision for both uncemented arthroplasties and operations performed at a non-pelvic trauma centre. Total hip arthroplasty secondary to an operatively treated acetabular fracture provides good symptomatic relief. These patients are, however, complex cases and are probably best treated at specialist centres with both pelvic trauma surgeons and arthroplasty surgeons proficient in complex revisions present. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance of Non-Cemented, Hemispherical, Rim-Fit, Hydroxyapatite Coated Acetabular Component.

PubMed

John, Thomas K; Ghosh, Gaurav; Ranawat, Chitranjan S; Ranawat, Amar S; Meftah, Morteza

2015-12-01

The purpose of this study was to assess the durability of a non-cemented, hemispherical rim-fit, hydroxyapatite coated cup with a highly cross-linked polyethylene in 223 total hip arthroplasties. At 6-years follow-up (range, 5-9), there were no cup revisions for osteolysis or loosening. Radiologic evidence of osseointegration was based on presence of Stress Induced Reactive Cancellous Bone and radial trabeculae, seen in 47% and 93% of cups, respectively; both were most prevalent in Zone 1. There was no interference demarcation in any zones. Two cups were revised (0.9%): one for dislocation and another for infection. The Kaplan-Meier survivorship for cup revision for any failure (infection, dislocation) was 99% and for mechanical failure (osteolysis, loosening) was 100%. This design has excellent safety, efficacy and durability. Copyright © 2015 Elsevier Inc. All rights reserved.

Managing acetabular fractures in the elderly with fixation and primary arthroplasty: aiming for early weightbearing.

PubMed

Rickman, Mark; Young, James; Trompeter, Alex; Pearce, Rachel; Hamilton, Mark

2014-11-01

Osteoporotic acetabular fractures in the elderly are becoming more common. Regardless of treatment, most patients are managed with a period of protected weightbearing, even if a THA has been performed. We have tried to treat these patients analogously to geriatric femoral neck fractures in a way that allows immediate full weightbearing. We determined return to mobility, length of hospital stay (LOS), radiographic outcomes, and complications in a series of elderly osteoporotic patients treated for acetabular fractures with early fracture fixation and simultaneous THA, allowing full weightbearing immediately postoperatively. Since 2009, one surgeon (MR) used a consistent approach for fracture fixation and THA with immediate weightbearing in all patients older than 65 years with acetabular fractures who were fit for surgery and whose injuries were deemed osteoporotic fractures (low-energy mechanisms) meeting particular radiographic criteria (significant marginal impaction or femoral head damage). Twenty-four patients met these criteria and were reviewed at a mean of 24 months (range, 8-38 months). Mean age was 77 years (range, 63-90 years), and eight patients were women. The surgical technique included plate stabilization of both acetabular columns plus simultaneous THA using a tantalum socket and a cemented femoral stem. Clinical and note reviews were conducted to ascertain return to mobility, LOS, and postoperative complications. Component migration and fracture healing were assessed on plain radiographs. All patients mobilized with full weightbearing by Day 7 postoperatively. Only one patient remained dependent on a frame to mobilize at discharge. At 6 weeks, two patients already required no walking aids. At 6 months, patients were using a single stick at home at most, and all patients had managed stairs. Mean LOS was 18 days (range, 10-36 days). Radiographically, no component migration was seen in any patient. Seventeen of 24 fractures (71%) healed radiographically by 12 weeks, and all healed by 6 months. We recorded one superficial wound infection, one symptomatic deep venous thrombosis, and one in-hospital death from myocardial infarction. Selected older patients with acetabular fractures may be managed using immediate weightbearing after fracture fixation and THA. However, this surgery is complex and requires a mixed skill set. Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

[Early aseptic loosening of the CF 30 femoral stem].

PubMed

Kovanda, M; Havlícek, V; Hudec, J

2007-02-01

The CF 30 stem in combination with a cementless acetabulum was used at the First Department of Orthopedic Surgery in Brno in the years 1994 to 1995. From the second year following implantation, aseptic stem loosening was recorded. In order to find explanation of this early loosening, the authors, in cooperation with the Institute of Solid Mechanics, Mechatronics and Biomechanics, carried out the stress-strain analysis in a model system. Eighty patients (31 men and 49 women) received a cemented CF30 femoral component in 1994. Of them, 16 patients underwent revision arthroplasty, three died of causes unrelated to the surgery, and four were lost to follow-up. The final clinical and radiographic check-up was carried out in 2001. The results of a comprehensive examination were available in 57 patients with a CF30 stem. The patients were evaluated on the basis of the Harris hip score and anteroposterior radiographs of the hip. X-ray films obtained immediately after surgery and those taken at regular intervals during follow-up were compared. The following characteristics were noted: translucent lines in individual zones along the stem at the cement-bone interface; osteolysis, i. e., non-linear translucent areas, at least 5 mm long, at the cement-bone interface; and subsidence of the femoral component, i. e., migration of the stem distal to the tip of the greater trochanter. The CF 30 stem survival curve showed that aseptic stem loosening occurred from post-implantation year 2, and increased during the following years. At 6 years and 6 months, a total of 16 patients underwent revision surgery, involving reimplantation in 14 and implant removal in 2 patients. Potential causes of aseptic loosening: Polyethylene wear.However, no acetabular loosening was found in this group, although acetabular components are reported to become loose more often than femoral components. By comparison of the stem survival curves for Poldi and CF 30 stems it appeared that, at 6 years and 6 months, the Poldi stem survival curve showed better results. Matt surface finish of the stem. However, the link between the CF 30 stem and cement was so strong that, in all 16 revised hips, the stem was removed together with nearly a complete cement mantle. The authors therefore dismiss this as a cause. Also, in the remaining cases of CF 30 aseptic loosening, which had not been revised, radiographic evidence suggested loosening between bone and cement. The authors did not find any movement of the CF stem in its cement mantle. The stem always fitted in with the cement mantle. Erroneous surgical technique or cementing was unlikely. The procedures were performed by experienced orthopedic surgeons who used the second-generation cementing technique. In patients with a Poldi stem, the first-generation cementing method was used and the proportion of aseptic loosening at 6 years of follow-up was only 4 %. In contrast, loosening in patients with the CF 30 stem was 20 % at 6 years and 6 months postoperatively. Shape of the CF 30 stem with the intention to find a relationship between stem shape and its early aseptic loosening, the authors started cooperation with the Institute of Solid Mechanics, Mechatronics and Biomechanics at the Faculty of Mechanical Engineering, Brno University of Technology. Using the method of finite elements, they carried out the stressstrain analysis in a model system. Stress at the cement-bone interface in the CF 30 stem was higher than in the Poldi stem, and this difference was statistically significant. The authors believe that the more frequent loosening found in patients with the CF 30 stem can be accounted for by its shape. The survival curve for the CF 30 femoral stem did not show good results, and therefore this stem is not recommended for implantation. The authors suggest that a more frequent early aseptic loosening of CF 30 stems may have been caused by its unsuitable shape.

Debonding of porous coating of a threaded acetabular component: retrieval analysis.

PubMed

Łapaj, Łukasz; Markuszewski, Jacek; Rybak, Tomasz; Wierusz-Kozłowska, Małgorzata

2013-01-01

This report presents a case of debonding of plasma sprayed porous titanium coating from a threaded acetabular component which caused aseptic loosening of the implant. Weight bearing after delamination caused abrasive damage of the acetabular shell, and particles of the coating embedded in the acetabular liner. Microscopic examination of periprosthetic tissues showed presence of metal particles and macrophage infiltration. Despite microscopic examination of the retrieved component the cause of debonding remains unclear. Copyright © 2012 Elsevier Ltd. All rights reserved.

Component Position and Metal Ion Levels in Computer-Navigated Hip Resurfacing Arthroplasty.

PubMed

Mann, Stephen M; Kunz, Manuela; Ellis, Randy E; Rudan, John F

2017-01-01

Metal ion levels are used as a surrogate marker for wear in hip resurfacing arthroplasties. Improper component position, particularly on the acetabular side, plays an important role in problems with the bearing surfaces, such as edge loading, impingement on the acetabular component rim, lack of fluid-film lubrication, and acetabular component deformation. There are little data regarding femoral component position and its possible implications on wear and failure rates. The purpose of this investigation was to determine both femoral and acetabular component positions in our cohort of mechanically stable hip resurfacing arthroplasties and to determine if these were related to metal ion levels. One hundred fourteen patients who had undergone a computer-assisted metal-on-metal hip resurfacing were prospectively followed. Cobalt and chromium levels, Harris Hip, and UCLA activity scores in addition to measures of the acetabular and femoral component position and angles of the femur and acetabulum were recorded. Significant changes included increases in the position of the acetabular component compared to the native acetabulum; increase in femoral vertical offset; and decreases in global offset, gluteus medius activation angle, and abductor arm angle (P < .05). Multiple regression analysis found no significant predictors of cobalt and chromium metal ion levels. Femoral and acetabular components placed in acceptable position failed to predict increased metal ion levels, and increased levels did not adversely impact patient function or satisfaction. Further research is necessary to clarify factors contributing to prosthesis wear. Copyright © 2016 Elsevier Inc. All rights reserved.

Treatment of acetabular fractures in older patients-introduction of a new implant for primary total hip arthroplasty.

PubMed

Resch, H; Krappinger, D; Moroder, P; Auffarth, A; Blauth, M; Becker, J

2017-04-01

Fractures of the acetabulum in younger patients are commonly treated by open reduction and internal fixation. For elderly patients, stable primary total hip arthroplasty with the advantage of immediate postoperative mobilization might be the adequate treatment. For this purpose, a sufficiently stable fixation of the acetabular component is required. Between August 2009 and 2014, 30 cases were reported in which all patients underwent total hip arthroplasty additionally to a customized implant designed as an antiprotrusion cage. Inclusion criteria were an acetabular fracture with or without a previous hemiarthroplasty, age above 65 years, and pre-injury mobility dependent on a walking frame at the most. The median age was 79.9 years (65-92), and of 30 fractures, 25 were primary acetabular fractures (83%), four periprosthetic acetabular fractures (14%), and one non-union after a failed ORIF (3%). The average time from injury to surgery was 9.4 days (3-23) and 295 days for the non-union case. Mean time of surgery was 154.4 min (range 100 to 303). In 21 cases (70%), mobilization with full weight bearing was possible within the first 10 days. Six patients died before the follow-up examination 3 and 6 months after surgery, while 24 patients underwent radiologic examination showing consolidated fractures in bi-plane radiographs. In 9 patients, additional CT scan was performed which confirmed the radiographical results. 13 had regained their pre-injury level of mobility including the non-union case. Only one patient did not regain independent mobility. Four complications were recognized with necessary surgical revision (one prosthetic head dislocation, one pelvic cement leakage, one femoral shaft fracture, and one infected hematoma). The presented cage provides the possibility of early mobilization with full weight bearing which represents a valuable addition to the treatment spectrum in this challenging patient group.

Fixation strength analysis of cup to bone material using finite element simulation

NASA Astrophysics Data System (ADS)

Anwar, Iwan Budiwan; Saputra, Eko; Ismail, Rifky; Jamari, J.; van der Heide, Emile

2016-04-01

Fixation of acetabular cup to bone material is an important initial stability for artificial hip joint. In general, the fixation in cement less-type acetabular cup uses press-fit and screw methods. These methods can be applied alone or together. Based on literature survey, the additional screw inside of cup is effective; however, it has little effect in whole fixation. Therefore, an acetabular cup with good fixation, easy manufacture and easy installation is required. This paper is aiming at evaluating and proposing a new cup fixation design. To prove the strength of the present cup fixation design, the finite element simulation of three dimensional cup with new fixation design was performed. The present cup design was examined with twist axial and radial rotation. Results showed that the proposed cup design was better than the general version.

High-precision measurements of cementless acetabular components using model-based RSA: an experimental study.

PubMed

Baad-Hansen, Thomas; Kold, Søren; Kaptein, Bart L; Søballe, Kjeld

2007-08-01

In RSA, tantalum markers attached to metal-backed acetabular cups are often difficult to detect on stereo radiographs due to the high density of the metal shell. This results in occlusion of the prosthesis markers and may lead to inconclusive migration results. Within the last few years, new software systems have been developed to solve this problem. We compared the precision of 3 RSA systems in migration analysis of the acetabular component. A hemispherical and a non-hemispherical acetabular component were mounted in a phantom. Both acetabular components underwent migration analyses with 3 different RSA systems: conventional RSA using tantalum markers, an RSA system using a hemispherical cup algorithm, and a novel model-based RSA system. We found narrow confidence intervals, indicating high precision of the conventional marker system and model-based RSA with regard to migration and rotation. The confidence intervals of conventional RSA and model-based RSA were narrower than those of the hemispherical cup algorithm-based system regarding cup migration and rotation. The model-based RSA software combines the precision of the conventional RSA software with the convenience of the hemispherical cup algorithm-based system. Based on our findings, we believe that these new tools offer an improvement in the measurement of acetabular component migration.

Should we worry about periacetabular interference gaps in hip resurfacing?

PubMed

Gomes, Bruno; Olsen, Michael; Donnelly, Michael; Kumar, Ashesh; Schemitsch, Emil H

2013-02-01

Press-fit acetabular component seating in hip resurfacing can be challenging as a strong interference fit is required. It has not been established whether reducing the acetabular underream minimizes incomplete component seating or leads to increased acetabular loosening. We examined (1) the incidence and natural history of postoperative interference gaps in hip resurfacing and (2) whether reduction of the acetabular underream from 2 mm to 1 mm reduces the incidence of periacetabular interference gaps. Of 327 Birmingham Hip™ Resurfacings (Smith & Nephew Inc, Memphis, TN, USA) performed by a single surgeon from 2005 to 2010, we evaluated 306 hips with a minimum 1-year radiographic followup. Postoperative periacetabular interference gaps were monitored for radiographic gap resolution at latest followup. The frequency of incomplete component seating was compared between acetabula prepared with 1- and 2-mm underream techniques. Minimum followup was 1 year (mean, 2.7 years; range, 1-6 years). Fifty-one percent of the postoperative radiographs demonstrated the presence of a periacetabular interference gap. At latest followup, 96% of these gaps were no longer visible. We observed a reduction in the number of interference gaps identified when acetabular preparation changed from a 2-mm underream (63%) to a 1-mm underream (39%). There were no revisions due to acetabular failure. Periacetabular interference gaps were common in this series but not associated with acetabular component failure. The use of a 1-mm underream is sufficient for adequate short-term press-fit fixation of the acetabular component in Birmingham Hip™ Resurfacing arthroplasty. Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Mating of a PROSTALAC spacer with an intramedullary nail for reconstruction of an infected interprosthetic femoral shaft fracture: a case report.

PubMed

Kamath, Atul F; Austin, Daniel; Lee, Gwo-Chin

2012-08-01

Reconstruction for concurrent infection of an ipsilateral total hip arthroplasty (THA) and total knee arthroplasty (TKA) is a challenge. We report a 2-stage reconstruction of a THA for chronic infection of both the THA and TKA with severe femoral bone loss secondary to interprosthetic fractures. The reconstruction involved using a custom-made, temporary, antibiotic-impregnated PROSTALAC spacer mated with an intramedullary nail. The acetabulum was then exposed and the necrotic cartilage was removed and curetted. The acetabulum was reamed to accept a PROSTALAC acetabular shell. The shell was cemented into the acetabulum with antibiotic cement. The custom-made spacer was then inserted distally first into the tibia. The distal end of the intramedullary nail was interlocked with a bicortical bolt to minimise nail rotation. Antibiotic-impregnated cement was moulded around the nail and spacer. The proximal end of the spacer was then reduced into the acetabular socket, and the joint was irrigated and the wound closed. A customised abduction brace was fitted, and partial weight bearing was allowed. Sufficient leg length, soft-tissue tension, and range of hip motion were restored, and a total femur and constrained liner was re-implanted 4 months later. Mating of an intramedullary nail with a PROSTALAC spacer is a viable reconstructive option.

Endoscopic or arthroscopic iliopsoas tenotomy for iliopsoas impingement following total hip replacement. A prospective multicenter 64-case series.

PubMed

Guicherd, W; Bonin, N; Gicquel, T; Gedouin, J E; Flecher, X; Wettstein, M; Thaunat, M; Prevost, N; Ollier, E; May, O

2017-12-01

Impingement between the acetabular component and the iliopsoas tendon is a cause of anterior pain after total hip replacement (THR). Treatment can be non-operative, endoscopic or arthroscopic, or by open revision of the acetabular component. Few studies have assessed these options. The present study hypothesis was that endo/arthroscopic treatment provides rapid pain relief with a low rate of complications. A prospective multicenter study included 64 endoscopic or arthroscopic tenotomies for impingement between the acetabular component and the iliopsoas tendon, performed in 8 centers. Mean follow-up was 8months, with a minimum of 6months and no loss to follow-up. Oxford score, patient satisfaction, anterior pain and iliopsoas strength were assessed at last follow-up. Complications and revision procedures were collated. Forty-four percent of patients underwent rehabilitation. At last follow-up, 92% of patients reported pain alleviation. Oxford score, muscle strength and pain in hip flexion showed significant improvement. The complications rate was 3.2%, with complete resolution. Mean hospital stay was 0.8 nights. In 2 cases, arthroscopy revealed metallosis, indicating revision of the acetabular component. The only predictive factor was acetabular projection on oblique view. Rehabilitation significantly improved muscle strength. Endoscopic or arthroscopic tenotomy for impingement between the acetabular component and the iliopsoas tendon following THR significantly alleviated anterior pain in more than 92% of cases. The low complications rate makes this the treatment of choice in case of failure of non-operative management. Arthroscopy also reorients diagnosis in case of associated joint pathology. Projection of the acetabular component on preoperative oblique view is the most predictive criterion, guiding treatment. Copyright © 2017. Published by Elsevier Masson SAS.

The Morscher Press-Fit Acetabular Component: An Independent Long-Term Review at 18-22 Years.

PubMed

Gwynne-Jones, David P; Lash, Heath W R; James, Andrew W; Iosua, Ella E; Matheson, John A

2017-08-01

There are relatively few 20-year results of uncemented acetabular components, and most of these are modular designs. This study reports the 20-year results of a monoblock press-fit acetabular component. A total of 122 total hip arthroplasties (111 patients) using the Morscher cup were reviewed at a mean of 19.7 years. The average age at implantation was 57.3 years (range, 36-74 years), and 81 (66%) were men. Twenty-two patients (25 hips) had died. Seven hips were revised, including 5 acetabular revisions. Six patients (6 hips) declined to participate but were known not to have been revised. The mean Oxford hip score was 41.1 (range, 22-48), and the mean reduced Western Ontario and McMaster Universities Osteoarthritis Index score was 5.7/48 (range, 0-24). Eccentric wear was seen in 13 (15.7%) and major osteolysis in 14 (17%) of 82 surviving hips with radiographs. The all-cause revision rate was 0.32 per 100 observed component years (95% confidence interval [CI], 0.13-0.66). The 20-year Kaplan-Meier survival was 93.4% (CI, 86.6-96.8) for all-cause revisions, 95.5% (CI, 89.4-98.1) for any acetabular revision, and 97.1% (CI, 91.2-99.1) for acetabular aseptic loosening, wear, or osteolysis. The Morscher acetabular component has continued to perform well at 20 years despite using conventional polyethylene with results that match or surpass other cementless acetabulae. Copyright © 2017 Elsevier Inc. All rights reserved.

A femoral component inserted without cement in total hip arthroplasty. A study of the Tri-Lock component with an average ten-year duration of follow-up.

PubMed

Burt, C F; Garvin, K L; Otterberg, E T; Jardon, O M

1998-07-01

Seventy-four total hip arthroplasties in sixty-six patients were performed, between 1983 and 1986, with use of a Tri-Lock femoral component inserted without cement. This tapered cobalt-chromium component has a fixed head and a circumferential proximal porous coating. Follow-up was conducted with use of a questionnaire, physical examination, and radiographic analysis. At the time of the latest follow-up, fifteen patients (eighteen hips) had died, three patients (four hips) had been lost to follow-up, and one patient (one hip) had refused to participate in the follow-up study; however, the status of fifteen hips at the time of death could be verified. Thus, clinical follow-up data were available for sixty-six of the original seventy-four hips. The average age at the time of the operation was sixty-two years (range, seventeen to eighty-four years), and the average interval between the operation and the latest follow-up evaluation was 10.0 years (range, 8.3 to 11.6 years). The Harris hip score was determined for forty-three hips (forty-one patients) in which the prosthesis was in situ at the time of the latest follow-up. The score was good for thirteen hips and excellent for twenty-eight, so the rate of clinical success was 95 per cent. Two patients had a fair result. One of them had persistent pain and the other had limited motion, but neither had radiographic evidence of loosening of the femoral or acetabular component. All forty-one patients were satisfied with the result. The probability (with standard error) of survival of the femoral component at ten years, with revision as the end point, was 0.95 +/- 0.03. The rate of revision of the femoral component because of aseptic loosening was one (2 per cent) of sixty-six. The overall rate of aseptic loosening of the femoral component in the hips that were followed radiographically was two (4 per cent) of forty-seven. Only one (2 per cent) of the forty-seven acetabular cups had evidence of aseptic loosening. There was no radiographic evidence of distal osteolysis around the prostheses that were well fixed. Proximal osteolysis was present in five (11 per cent) of forty-seven hips, but none of the lesions compromised the stability of the prosthesis or the bone and there were no associated fractures. At an average of ten years postoperatively, the Tri-Lock femoral component functioned well overall and patient satisfaction was high.

The jumbo acetabular component for acetabular revision: Curtain Calls and Caveats.

PubMed

Lachiewicz, P F; Watters, T S

2016-01-01

The 'jumbo' acetabular component is now commonly used in acetabular revision surgery where there is extensive bone loss. It offers high surface contact, permits weight bearing over a large area of the pelvis, the need for bone grafting is reduced and it is usually possible to restore centre of rotation of the hip. Disadvantages of its use include a technique in which bone structure may not be restored, a risk of excessive posterior bone loss during reaming, an obligation to employ screw fixation, limited bone ingrowth with late failure and high hip centre, leading to increased risk of dislocation. Contraindications include unaddressed pelvic dissociation, inability to implant the component with a rim fit, and an inability to achieve screw fixation. Use in acetabulae with < 50% bone stock has also been questioned. Published results have been encouraging in the first decade, with late failures predominantly because of polyethylene wear and aseptic loosening. Dislocation is the most common complication of jumbo acetabular revisions, with an incidence of approximately 10%, and often mandates revision. Based on published results, a hemispherical component with an enhanced porous coating, highly cross-linked polyethylene, and a large femoral head appears to represent the optimum tribology for jumbo acetabular revisions. ©2016 The British Editorial Society of Bone & Joint Surgery.

Impaction grafted bone chip size effect on initial stability in an acetabular model: Mechanical evaluation.

PubMed

Holton, Colin; Bobak, Peter; Wilcox, Ruth; Jin, Zhongmin

2013-01-01

Acetabular bone defect reconstruction is an increasing problem for surgeons with patients undergoing complex primary or revision total hip replacement surgery. Impaction bone grafting is one technique that has favourable long-term clinical outcome results for patients who undergo this reconstruction method for acetabular bone defects. Creating initial mechanical stability of the impaction bone graft in this technique is known to be the key factor in achieving a favourable implant survival rate. Different sizes of bone chips were used in this technique to investigate if the size of bone chips used affected initial mechanical stability of a reconstructed acetabulum. Twenty acetabular models were created in total. Five control models were created with a cemented cup in a normal acetabulum. Then five models in three different groups of bone chip size were constructed. The three groups had an acetabular protrusion defect reconstructed using either; 2-4 mm(3), 10 mm(3) or 20 mm(3) bone chip size for impaction grafting reconstruction. The models underwent compression loading up to 9500 N and displacement within the acetabular model was measured indicating the initial mechanical stability. This study reveals that, although not statistically significant, the largest (20 mm(3)) bone chip size grafted models have an inferior maximum stiffness compared to the medium (10 mm(3)) bone chip size. Our study suggests that 10 mm(3) size of bone chips provide better initial mechanical stability compared to smaller or larger bone chips. We dismissed the previously held opinion that the biggest practically possible graft is best for acetabular bone graft impaction.

Modification of the explant system for the removal of well fixed hip resurfacing sockets.

PubMed

Rawal, Jaikirty S; Soler, J Agustin; Rhee, Jae S; Dobson, Michael H; Konan, Sujith; Haddad, Fares S

2010-10-01

A major concern during revision hip arthroplasty is acetabular bone loss during the extraction of well-fixed acetabular components. Despite the good early survivorship of resurfacing prostheses, revision surgery may be necessary. We recommend the use of the Explant acetabular extraction system (Zimmer, Warsaw, Ind) with a trial liner to preserve acetabular bone stock. We present 2 cases of revised resurfacings using this technique, demonstrating minimal interference to the remaining acetabular bone. Copyright © 2010 Elsevier Inc. All rights reserved.

Can cemented dual-mobility cups be used without a reinforcement device in cases of mild acetabular bone stock alteration in total hip arthroplasty?

PubMed

Haen, T X; Lonjon, G; Vandenbussche, E

2015-12-01

Cemented versions of dual-mobility cups (DMCs), helpful in cases of bone stock alteration, are usually used in association with a reinforcement device. To simplify the intervention in elderly subjects or those with a poor bone stock, the cups can be cemented directly into the bone, but the long-term result remains uncertain. We conducted a retrospective study in this population so as to: (1) assess whether cemented fixation of a DMC without a reinforcement device leads to a higher loosening rate, (2) confirm its efficacy in preventing dislocations in subjects at high risk of instability, and (3) measure the functional results. Cemented fixation of a DMC is reliable in cases of moderate alteration of bone stock. Sixty-four patients (66 hips) undergoing implantation of a cemented DMC (Saturne™) without a reinforcement device were included in this single-center retrospective study. Their mean age was 79.8 years (range, 40-95 years). The indications varied: hip osteoarthritis (30.3%), prosthesis revision (44.0%), and trauma (25.8%). The patients were evaluated radiologically and clinically at follow-up. The main evaluation criterion was the revision rate for aseptic loosening. Dislocations, the infection rate, and the Postel Merle d'Aubigné (PMA) score were noted. At the mean follow-up of 4.2 years, three (4.6%) patients had been lost to follow-up and 22 (33.3%) had died. There was one case of aseptic loosening (1.5%). Cup survival was 98% at 5 years (95%CI [94-100]). There were no dislocations. There was one revision for infection. The mean PMA score was 15.5 (range, 9-18). The frequency of acetabular loosening was comparable to the frequency in cemented DMCs with a reinforcement device. A cemented DMC without a reinforcement device is possible and is a simple and viable option when there is moderate bone stock alteration. IV, retrospective cohort study. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Does Increased Coefficient of Friction of Highly Porous Metal Increase Initial Stability at the Acetabular Interface?

PubMed

Goldman, Ashton H; Armstrong, Lucas C; Owen, John R; Wayne, Jennifer S; Jiranek, William A

2016-03-01

Highly porous metal acetabular components illustrate a decreased rate of aseptic loosening in short-term follow-up compared with previous registry data. This study compared the effect of component surface roughness at the bone-implant interface and the quality of the bone on initial pressfit stability. The null hypothesis is that a standard porous coated acetabular cup would show no difference in initial stability as compared with a highly porous acetabular cup when subjected to a bending moment. Second, would bone mineral density (BMD) be a significant variable under these test conditions. In a cadaveric model, acetabular cup micromotion was measured during a 1-time cantilever bending moment applied to 2 generations of pressfit acetabular components. BMD data were also obtained from the femoral necks available for associated specimen. The mean bending moment at 150 μm was not found to be significantly different for Gription (24.6 ± 14.0 N m) cups vs Porocoat (25 ± 10.2 N m; P > .84). The peak bending moment tolerated by Gription cups (33.9 ± 20.3 N m) was not found to be significantly different from Porocoat (33.5 ± 12.2 N m; P > .92). No correlation between BMD and bending moment at 150 μm of displacement could be identified. The coefficient of friction provided by highly porous metal acetabular shells used in this study did not provide better resistance to migration under bending load when compared with a standard porous coated component. Copyright © 2016 Elsevier Inc. All rights reserved.

Cancellous and cortical bone mineral density around an elastic press-fit socket in total hip arthroplasty.

PubMed

Pakvis, Dean F M; Heesterbeek, Petra J C; Severens, Marianne; Spruit, Maarten

2016-12-01

Background and purpose - The acetabular component has remained the weakest link in hip arthroplasty for achievement of long-term survival. One of the possible explanatory factors for acetabular failure has been acetabular stress shielding. For this, we investigated the effects of a cementless elastic socket on acetabular bone mineral density (BMD). Patients and methods - During 2008-2009, we performed a single-center prospective cohort trial on 25 patients (mean age 64 (SD 4), 18 females) in whom we implanted a cementless elastic press-fit socket. Using quantitative BMD measurements on CT, we determined the change in BMD surrounding the acetabular component over a 2-year follow-up period. Results - We found a statistically significant decrease in cancellous BMD (-14% to -35%) and a stable level of cortical BMD (5% to -5%) surrounding the elastic press-fit cup during the follow-up period. The main decrease was seen during the first 6 months after implantation. During the second year, cancellous BMD showed a further decrease in the medial and lower acetabular regions. Interpretation - We found no evidence that an elastic press-fit socket would prevent acetabular stress shielding during a 2-year follow-up.

[Revision hip arthroplasty by Waldemar Link custom-made total hip prosthesis].

PubMed

Medenica, Ivica; Luković, Milan; Radoicić, Dragan

2010-02-01

The number of patients undergoing hip arthroplasty revision is constantly growing. Especially, complex problem is extensive loss of bone stock and pelvic discontinuity that requires reconstruction. The paper presented a 50-year old patient, who ten years ago underwent a total cement artrhroplasty of the left hip. A year after the primary operation the patient had difficulties in walking without crutches. Problems intensified in the last five years, the patient had severe pain, totally limited movement in the left hip and could not walk at all. Radiographically, we found loose femoral component, massive loss of bone stock of proximal femur, acetabular protrusion and a consequent pelvic discontinuity. Clinically, a completely disfunctional left hip joint was registered (Harris hip score--7.1). We performed total rearthroplasty by a custom-made Waldemar Link total hip prosthesis with acetabular antiprotrusio cage and compensation of bone defects with a graft from the bone bank. A year after the operation, we found clinically an extreme improvement in Harris hip score--87.8. Radiographically, we found stability of implanted components, a complete graft integration and bone bridging across the site of pelvic discontinuity. Pelvic discontinuity and massive loss of proximal femoral bone stock is a challenging and complex entity. Conventional prostheses cannot provide an adequate fixation and stability of the hip. Application of custom-made prosthesis (measured specificaly for a patient) and additional alografting bone defects is a good method in revision surgery after unsuccessful hip arthroplasty with extensive bone defects.

"Tripolar" hip arthroplasty for failed hip resurfacing: nineteen years follow-up.

PubMed

Scheerlinck, T; Casteleyn, P P

2001-10-01

The authors describe the case of a 37-year-old patient who sustained a subcapital femoral neck fracture six months after ICLH double-cup hip resurfacing. As the polyethylene acetabular resurfacing component was undamaged and well fixed, a standard femoral stem with a bipolar head was inserted. The outer diameter of the bipolar head was chosen to fit the resurfacing socket. The "tripolar" hip arthroplasty has functioned well for 19 years and was revised for aseptic cup loosening. The cemented femoral stem was still well fixed and was not revised. Although the "tripolar" hip has functioned well in our case, we believe it is not indicated for metal on metal bearings. In this case the use of an appropriate modular head with a correct head-socket clearance is preferred.

Promising Mid-term Results With a Cup-cage Construct for Large Acetabular Defects and Pelvic Discontinuity.

PubMed

Amenabar, Tomas; Rahman, Wael A; Hetaimish, Bandar M; Kuzyk, Paul R; Safir, Oleg A; Gross, Allan E

2016-02-01

Restoring normal anatomy and achieving stable fixation of the acetabular component can be especially challenging when the surgeon must deal with severe acetabular defects and/or pelvic discontinuity. The cup-cage (CC) construct, where an ilioischial cage is cemented within a biologically fixed porous metal cup, has emerged as an excellent option to treat such challenges. We sought to determine (1) mid-term Kaplan-Meier survival; (2) clinical outcomes based on Merle d'Aubigné-Postel scores; (3) radiological outcomes based primarily on construct migration; and (4) the complication rate for a series of 67 CC procedures performed at our institution. All hip revision procedures between January 2003 and March 2012 where a CC was used (with the exception of tumor cases or acute fracture; four total cases) that had a minimum 2-year followup and that had been seen within the last 2 years were included in this retrospective review. Acetabular bone loss and presence of pelvic discontinuity were assessed according to the Gross classification. Sixty-seven CC procedures with an average followup of 74 months (range, 24-135 months; SD, 34.3) months were identified; 26 of 67 (39%) were Gross Type IV and 41 of 67 (61%) were Gross Type V (pelvic discontinuity). Postoperative clinical and radiological evaluation was done annually. Merle d'Aubigné-Postel scores were recorded and all radiographs were compared with the 6-week postoperative radiographs to evaluate for radiographic loosening or migration. Failure was defined as revision surgery for any cause, including infection. The 5-year Kaplan-Meier survival rate with revision for any cause representing failure was 93% (95% confidence interval [CI], 83.1-97.4), and the 10-year survival rate was 85% (95% CI, 67.2-93.8). The Merle d'Aubigné-Postel score improved significantly from a mean of 6 preoperatively to 13 postoperatively (p < 0.001). Four CC had nonprogressive radiological migration of the ischial flange and they remain stable. We believe that the CC construct is a suitable choice to treat chronic pelvic discontinuity; it also remains a reliable option for the treatment of severe acetabular bone defects if stable fixation cannot be obtained through the use of a trabecular metal cup with or without augments. Level IV, therapeutic study.

Well-fixed acetabular component retention or replacement: the whys and the wherefores.

PubMed

Blaha, J David

2002-06-01

Occasionally the adult reconstructive surgeon is faced with a well-fixed acetabular component that is associated with an arthroplasty problem that ordinarily would require removal and replacement of the cup. Removal of a well-fixed cup is associated with considerable morbidity in bone loss, particularly in the medial wall of the acetabulum. In such a situation, retention of the cup with exchange only of the polyethylene liner may be possible. As preparation for a prospective study, I informally reviewed my experience of cup retention or replacement in revision total hip arthroplasty. An algorithm for retaining or revising a well-fixed acetabular component is presented here. Copyright 2002, Elsevier Science (USA).

Survivorship analysis of failure pattern after revision total hip arthroplasty.

PubMed

Retpen, J B; Varmarken, J E; Jensen, J S

1989-12-01

Failure, defined as established indication for or performed re-revision of one or both components, was analyzed using survivorship methods in 306 revision total hip arthroplasties. The longevity of revision total hip arthroplasties was inferior to that of previously reported primary total hip arthroplasties. The overall survival curve was two-phased, with a late failure period associated with aseptic loosening of one or both components and an early failure period associated with causes of failure other than loosening. Separate survival curves for aseptic loosening of femoral and acetabular components showed late and almost simultaneous decline, but with a tendency toward a higher rate of failure for the femoral component. No differences in survival could be found between the Stanmore, Lubinus standard, and Lubinus long-stemmed femoral components. A short interval between the index operation and the revision and intraoperative and postoperative complications were risk factors for early failure. Young age was a risk factor for aseptic loosening of the femoral component. Intraoperative fracture of the femoral shaft was not a risk factor for secondary loosening. No difference in survival was found between primary cemented total arthroplasty and primary noncemented hemiarthroplasty.

The long-term in vivo behavior of polymethyl methacrylate bone cement in total hip arthroplasty.

PubMed

Oonishi, Hiroyuki; Akiyama, Haruhiko; Takemoto, Mitsuru; Kawai, Toshiyuki; Yamamoto, Koji; Yamamuro, Takao; Oonishi, Hironobu; Nakamura, Takashi

2011-10-01

The long-term success of cemented total hip arthroplasty (THA) has been well established. Improved outcomes, both radiographically and clinically, have resulted mainly from advances in stem design and improvements in operating techniques. However, there is concern about the durability of bone cement in vivo. We evaluated the physical and chemical properties of CMW1 bone cements retrieved from patients undergoing revision THA. CMW1 cements were retrieved from 14 patients who underwent acetabular revision because of aseptic loosening. The time in vivo before revision was 7-30 years. The bending properties of the retrieved bone cement were assessed using the three-point bending method. The molecular weight and chemical structure were analyzed by gel permeation chromatography and Fourier-transform infrared spectroscopy. The porosity of the bone cements was evaluated by 3-D microcomputer tomography. The bending strength decreased with increasing time in vivo and depended on the density of the bone cement, which we assume to be determined by the porosity. There was no correlation between molecular weight and time in vivo. The infrared spectra were similar in the retrieved cements and in the control CMW1 cements. Our results indicate that polymer chain scission and significant hydrolysis do not occur in CMW1 cement after implantation in vivo, even in the long term. CMW1 cement was stable through long-term implantation and functional loading.

Five to thirteen year results of a cemented dual mobility socket to treat recurrent dislocation.

PubMed

Hamadouche, Moussa; Ropars, Mickael; Rodaix, Camille; Musset, Thierry; Gaucher, François; Biau, David; Courpied, Jean Pierre; Huten, Denis

2017-03-01

Dual mobility (DM) socket has been associated with a low rate of dislocation following both primary and revision total hip arthroplasty (THA). However, little is known about the long-term efficiency of DM in the treatment of THA instability. The purpose of this retrospective study was to evaluate the outcome of a cemented DM socket to treat recurrent dislocation after a minimum of five year follow-up. The series included 51 patients with a mean age of 71.3 ± 11.5 (range, 41-98) years presenting with recurrent dislocation (mean 3.3). A single DM socket design was used consisting of a stainless steel outer shell with grooves with a highly polished inner surface articulating with a mobile polyethylene component. The femoral head was captured in the polyethylene component using a snap-fit type mechanism, the latter acting as a large unconstrained head inside the metal cup. At the minimum five year follow-up evaluation, 18 of the 51 patients deceased at a mean of 4.8 ± 2.3 years, three were lost to follow-up at a mean of 1.4 years, seven had been revised at a mean of 4.7 ± 3.1 years (range, 1.5-9.1), and the remaining 23 were still alive and did not have revision at a mean of 8.2 ± 2.4 years (range, 5-13 years). Of the seven revision, three were performed for further episodes of dislocation (at the large bearing for one patient and intra-prosthetic for two patients) after a mean 5.9 ± 2.9 years (range, 2.7-9.1), whereas two were performed for late sepsis and two for aseptic loosening of the acetabular component. Radiographic analysis did not reveal any further loosening on the acetabular side. The survival rate of the cup at ten years, using re-dislocation as the end-point, was 86.1 ± 8.4% (95% confidence interval, 69.7-100%). The survival rate of the cup at ten years, using revision for any reason as the end-point, was 75.2 ± 9.3% (95% confidence interval, 56.9-93.5%). A cemented dual mobility cup was able to restore hip stability in 94% of patients presenting with recurrent dislocating hips up to 13-year follow-up with none of the complications associated with constrained devices, as mechanical failure occurred in only 3.9% of the patients of this series. The overall reduced survival using revision for any reason as the end-point at ten years was related to this specific patients population that had various co-morbidities.

Curved-stem Hip Resurfacing

PubMed Central

2008-01-01

Hip resurfacing is an attractive concept because it preserves rather than removes the femoral head and neck. Most early designs had high failure rates, but one unique design had a femoral stem. Because that particular device appeared to have better implant survival, this study assessed the clinical outcome and long-term survivorship of a hip resurfacing prosthesis. Four hundred forty-five patients (561 hips) were retrospectively reviewed after a minimum of 20 years’ followup or until death; 23 additional patients were lost to followup. Patients received a metal femoral prosthesis with a small curved stem. Three types of acetabular reconstructions were used: (1) cemented polyurethane; (2) metal-on-metal; and (3) polyethylene secured with cement or used as the liner of a two-piece porous-coated implant. Long-term results were favorable with the metal-on-metal combination only. The mean overall Harris hip score was 92 at 2 years of followup. None of the 121 patients (133 hips) who received metal-on-metal articulation experienced failure. The failure rate with polyurethane was 100%, and the failure rate with cemented polyethylene was 41%. Hip resurfacing with a curved-stem femoral component had a durable clinical outcome when a metal-on-metal articulation was used. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18338217

Short-term survival of the trabecular metal cup is similar to that of standard cups used in acetabular revision surgery.

PubMed

Mohaddes, Maziar; Rolfson, Ola; Kärrholm, Johan

2015-02-01

The use of trabecular metal (TM) cups in revision surgery has increased worldwide during the last decade. Since the introduction of the TM cup in Sweden in 2006, this design has gradually replaced other uncemented designs used in Sweden. According to data from the Swedish Hip Arthroplasty Register (SHAR) in 2012, one-third of all uncemented first-time cup revisions were performed using a TM cup. We compared the risk of reoperation and re-revision for TM cups and the 2 other most frequently used cup designs in acetabular revisions reported to the SHAR. The hypothesis was that the performance of TM cups is as good as that of established designs in the short term. The study population consisted of 2,384 patients who underwent 2,460 revisions during the period 2006 through 2012. The most commonly used cup designs were the press-fit porous-coated cup (n = 870), the trabecular metal cup (n = 805), and the cemented all-polyethylene cup (n = 785). 54% of the patients were female, and the median age at index revision was 72 (19-95) years. Reoperation was defined as a second surgical intervention, and re-revision-meaning exchange or removal of the cup-was used as endpoint. The mean follow-up time was 3.3 (0-7) years. There were 215 reoperations, 132 of which were re-revisions. The unadjusted and adjusted risk of reoperation or re-revision was not significantly different for the TM cup and the other 2 cup designs. Our data support continued use of TM cups in acetabular revisions. Further follow-up is necessary to determine whether trabecular metal cups can reduce the re-revision rate in the long term, compared to the less costly porous press-fit and cemented designs.

Basic Science Considerations in Primary Total Hip Replacement Arthroplasty

PubMed Central

Mirza, Saqeb B; Dunlop, Douglas G; Panesar, Sukhmeet S; Naqvi, Syed G; Gangoo, Shafat; Salih, Saif

2010-01-01

Total Hip Replacement is one of the most common operations performed in the developed world today. An increasingly ageing population means that the numbers of people undergoing this operation is set to rise. There are a numerous number of prosthesis on the market and it is often difficult to choose between them. It is therefore necessary to have a good understanding of the basic scientific principles in Total Hip Replacement and the evidence base underpinning them. This paper reviews the relevant anatomical and biomechanical principles in THA. It goes on to elaborate on the structural properties of materials used in modern implants and looks at the evidence base for different types of fixation including cemented and uncemented components. Modern bearing surfaces are discussed in addition to the scientific basis of various surface engineering modifications in THA prostheses. The basic science considerations in component alignment and abductor tension are also discussed. A brief discussion on modular and custom designs of THR is also included. This article reviews basic science concepts and the rationale underpinning the use of the femoral and acetabular component in total hip replacement. PMID:20582240

The Transverse Acetabular Ligament as an Intraoperative Guide to Cup Abduction.

PubMed

Hiddema, Willem B; van der Merwe, Johan F; van der Merwe, Werner

2016-07-01

The success of a total hip arthroplasty relies on optimal acetabular cup placement to ensure mating of the femoral head and acetabular cup throughout all positions of the hip joint. Poor cup placement is associated with dislocation, impingement, microseparation, component loosening, and accelerated wear due to rim loading. This study examined a novel method of using the transverse acetabular ligament (TAL) to guide cup inclination during primary total hip arthroplasty. A descriptive study using 16 hips from 9 cadavers. A computer navigation system measured inclination and version of the acetabular component in 3 positions with the lower edge of cup: (1) flush with, (2) 5 mm proximal to, and (3) 5 mm distal to free border of the TAL. The median inclination angles were 44° in position (1), 30° in position (2), and 64° in position (3). The median anteversion angle for all positions was 19°. Cup inclination was acceptable when the lower edge of the cup was flush or within 5 mm proximal to the TAL. Copyright © 2016 Elsevier Inc. All rights reserved.

Long term survival of an hydroxyapatite-coated threaded cup in the presence of a high polythene wear rate.

PubMed

Datir, Sandeep P; Angus, Peter D

2010-01-01

We describe the long term clinical results and polythene wear rate measurement of 144 uncemented total hip arthroplasties in 118 patients (Male: Female-65: 53, Mean age: 52.8 years (range 21-78 years) performed between 1988 and 2000 using the Furlong HAC coated threaded acetabular cup. The mean follow-up for the group was 10.2 years (range: 5-17.5, median: 9.7). One femoral stem and two acetabular shells were revised due to aseptic loosening. The mean polythene wear rate was 0.24 mm/year. Ten-year survival for the acetabular and femoral components with radiological evidence of aseptic loosening as an end point was 99.15 (CI: 98.3-99.9) and 99.28 (CI: 98.5-99.9). There was no evidence of osteolysis around the femoral or acetabular components in spite of a relatively high polythene wear rate (0.24 mm/year). Our study demonstrates excellent survival of threaded HAC coated acetabular sockets at 10 years in spite of a relatively high polythene wear rate.

The long-term in vivo behavior of polymethyl methacrylate bone cement in total hip arthroplasty

PubMed Central

2011-01-01

Background and purpose The long-term success of cemented total hip arthroplasty (THA) has been well established. Improved outcomes, both radiographically and clinically, have resulted mainly from advances in stem design and improvements in operating techniques. However, there is concern about the durability of bone cement in vivo. We evaluated the physical and chemical properties of CMW1 bone cements retrieved from patients undergoing revision THA. Methods CMW1 cements were retrieved from 14 patients who underwent acetabular revision because of aseptic loosening. The time in vivo before revision was 7–30 years. The bending properties of the retrieved bone cement were assessed using the three-point bending method. The molecular weight and chemical structure were analyzed by gel permeation chromatography and Fourier-transform infrared spectroscopy. The porosity of the bone cements was evaluated by 3-D microcomputer tomography. Results The bending strength decreased with increasing time in vivo and depended on the density of the bone cement, which we assume to be determined by the porosity. There was no correlation between molecular weight and time in vivo. The infrared spectra were similar in the retrieved cements and in the control CMW1 cements. Interpretation Our results indicate that polymer chain scission and significant hydrolysis do not occur in CMW1 cement after implantation in vivo, even in the long term. CMW1 cement was stable through long-term implantation and functional loading. PMID:22103279

Initial stability of press-fit acetabular components under rotational forces.

PubMed

Fehring, Keith A; Owen, John R; Kurdin, Anton A; Wayne, Jennifer S; Jiranek, William A

2014-05-01

The primary goal of this study was to determine the initial press-fit stability in acetabular components without screw fixation. Mechanical testing was performed with the implantation of press-fit acetabular components in cadaveric specimens. No significant difference was found in load to failure testing between 1 and 2 mm of under-reaming. However, there was significant variability in bending forces required to create 150 μm of micromotion ranging from 49.3 N to 214.4 N. This study shows that cups implanted in a press-fit fashion, which are felt to be clinically stable, have high degrees of variability in resisting load and may be at risk for loosening. There is a need for more objective intra-operative techniques to test cup stability. © 2014.

10-year results of the uncemented Allofit press-fit cup in young patients.

PubMed

Streit, Marcus R; Weiss, Stefan; Andreas, Franziska; Bruckner, Thomas; Walker, Tilman; Kretzer, J Philippe; Ewerbeck, Volker; Merle, Christian

2014-08-01

Uncemented acetabular components in primary total hip arthroplasty (THA) are commonly used today, but few studies have evaluated their survival into the second decade in young and active patients. We report on a minimum 10-year follow-up of an uncemented press-fit acetabular component that is still in clinical use. We examined the clinical and radiographic results of our first 121 consecutive cementless THAs using a cementless, grit-blasted, non-porous, titanium alloy press-fit cup (Allofit; Zimmer Inc., Warsaw, IN) without additional screw fixation in 116 patients. Mean age at surgery was 51 (21-60) years. Mean time of follow-up evaluation was 11 (10-12) years. At final follow-up, 8 patients had died (8 hips), and 1 patient (1 hip) was lost to follow-up. 3 hips in 3 patients had undergone acetabular revision, 2 for deep infection and 1 for aseptic acetabular loosening. There were no impending revisions at the most recent follow-up. We did not detect periacetabular osteolysis or loosening on plain radiographs in those hips that were evaluated radiographically (n = 90; 83% of the hips available at a minimum of 10 years). Kaplan-Meier survival analysis using revision of the acetabular component for any reason (including isolated inlay revisions) as endpoint estimated the 11-year survival rate at 98% (95% CI: 92-99). Uncemented acetabular fixation using the Allofit press-fit cup without additional screws was excellent into early in the second decade in this young and active patient cohort. The rate of complications related to the liner and to osteolysis was low.

Pelvic position and movement during hip replacement.

PubMed

Grammatopoulos, G; Pandit, H G; da Assunção, R; Taylor, A; McLardy-Smith, P; De Smet, K A; Murray, D W; Gill, H S

2014-07-01

The orientation of the acetabular component is influenced not only by the orientation at which the surgeon implants the component, but also the orientation of the pelvis at the time of implantation. Hence, the orientation of the pelvis at set-up and its movement during the operation, are important. During 67 hip replacements, using a validated photogrammetric technique, we measured how three surgeons orientated the patient's pelvis, how much the pelvis moved during surgery, and what effect these had on the final orientation of the acetabular component. Pelvic orientation at set-up, varied widely (mean (± 2, standard deviation (sd))): tilt 8° (2sd ± 32), obliquity -4° (2sd ± 12), rotation -8° (2sd ± 14). Significant differences in pelvic positioning were detected between surgeons (p < 0.001). The mean angular movement of the pelvis between set-up and component implantation was 9° (sd 6). Factors influencing pelvic movement included surgeon, approach (posterior > lateral), procedure (hip resurfacing > total hip replacement) and type of support (p < 0.001). Although, on average, surgeons achieved their desired acetabular component orientation, there was considerable variability (2sd ± 16) in component orientation. We conclude that inconsistency in positioning the patient at set-up and movement of the pelvis during the operation account for much of the variation in acetabular component orientation. Improved methods of positioning and holding the pelvis are required. ©2014 The British Editorial Society of Bone & Joint Surgery.

Towards the optimal design of an uncemented acetabular component using genetic algorithms

NASA Astrophysics Data System (ADS)

Ghosh, Rajesh; Pratihar, Dilip Kumar; Gupta, Sanjay

2015-12-01

Aseptic loosening of the acetabular component (hemispherical socket of the pelvic bone) has been mainly attributed to bone resorption and excessive generation of wear particle debris. The aim of this study was to determine optimal design parameters for the acetabular component that would minimize bone resorption and volumetric wear. Three-dimensional finite element models of intact and implanted pelvises were developed using data from computed tomography scans. A multi-objective optimization problem was formulated and solved using a genetic algorithm. A combination of suitable implant material and corresponding set of optimal thicknesses of the component was obtained from the Pareto-optimal front of solutions. The ultra-high-molecular-weight polyethylene (UHMWPE) component generated considerably greater volumetric wear but lower bone density loss compared to carbon-fibre reinforced polyetheretherketone (CFR-PEEK) and ceramic. CFR-PEEK was located in the range between ceramic and UHMWPE. Although ceramic appeared to be a viable alternative to cobalt-chromium-molybdenum alloy, CFR-PEEK seems to be the most promising alternative material.

Fate of the unrevised cemented stem following cup only revision: 227 hips at an average of 6 years follow-up.

PubMed

McGonagle, L; Siney, P D; Raut, V V

2015-11-01

After primary total hip replacement, aseptic loosening of the acetabular cup is more common than loosening of the femoral stem. Removal of a well-fixed stem adds to operative time, blood loss, risk of bone loss and fracture. There is limited evidence that isolated cup revision can be a safe option in revision hip arthroplasty. We question the following regarding the unrevised cemented stem after isolated cup revision: 1) Does the unrevised stem require revision after isolated cup revision? 2) When is the stem subsequently revised? 3) Why is the stem subsequently revised? 4) Do unrevised stems exhibit radiographic loosening? We hypothesise that after isolated cup revision most unrevised stems do not need subsequent revision, and that most do not exhibit evidence of radiographic loosening. A retrospective analysis of all patients who underwent revision of the acetabular component only during revision hip arthroplasty between March 1970 and July 2013 was carried out. We assessed survival of the unrevised stem, reasons for subsequent revision, plus radiographic analysis for stem loosening. Two hundred and twenty-seven hips were included [215 patients with an average age at the time of primary surgery was 47 (13-70) years]. The Charnley stem was used in 161 cases; C-stem 65, Howse 1. Average time between primary surgery and cup revision was 15.9 (1.6-33.4) years. Average follow-up for all stems post-isolated cup revision was 6.1 (0.1-30.7) years. Twenty-eight stems (12.3%) were subsequently revised 5.1 (0.1-12.6) years after the isolated cup revision. Reasons for subsequent revision were: aseptic loosening (10); infection (8); dislocation (6); unreconstructable joint post-loose cup removal (2); fracture (2). Radiographic review was possible on 140 cases. Five femoral stems were revised and 2 others showed evidence of possible radiological loosening but were not revised. To our knowledge this is the largest series showing that isolated cup revision in the place of a well-fixed cemented stem is safe and is associated with ongoing good long-term survival of the stem. Level IV, retrospective case series. Copyright © 2015. Published by Elsevier Masson SAS.

Reconstruction of failed acetabular component in the presence of severe acetabular bone loss: a systematic review.

PubMed

Volpin, A; Konan, S; Biz, C; Tansey, R J; Haddad, F S

2018-04-13

Acetabular revision especially in the presence of severe bone loss is challenging. There is a paucity of literature critiquing contemporary techniques of revision acetabular reconstruction and their outcomes. The purpose of this study was to systematically review the literature and to report clinical outcomes and survival of contemporary acetabular revision arthroplasty techniques (tantalum metal shells, uncemented revision jumbo shells, reinforced cages and rings, oblong shells and custom-made triflange constructs). Full-text papers and those with an abstract in English published from January 2001 to January 2016 were identified through international databases. A total of 50 papers of level IV scientific evidence, comprising 2811 hips in total, fulfilled the inclusion criteria and were included. Overall, patients had improved outcomes irrespective of the technique of reconstruction as documented by postoperative hip scores. Our pooled analysis suggests that oblong cups components had a lower failure rate compared with other different materials considered in this review. Custom-made triflange cups had one of highest failure rates. However, this may reflect the complexity of revisions and severity of bone loss. The most common postoperative complication reported in all groups was dislocation. This review confirms successful acetabular reconstructions using diverse techniques depending on the type of bone loss and highlights key features and outcomes of different techniques. In particular, oblong cups and tantalum shells have successful survivorship.

Hip Resurfacing Using Highly Cross-linked Polyethylene: Prospective Study Results at 8.5 Years.

PubMed

Pritchett, James W

2016-10-01

Hip resurfacing is an option to consider when treating younger, more active patients. Advantages over total hip arthroplasty include a more normal gait and a lower incidence of thigh pain. In this prospective study, 190 hip resurfacing procedures (164 participants) were performed using a cobalt-chromium femoral component and a cementless acetabular cup with a 3.8-mm highly cross-linked polyethylene acetabular liner. The mean follow-up was 8.5 (range, 7-10) years. Two participants were lost to follow-up and 2 died. One participant underwent successful revision surgery for acetabular loosening. Four participants underwent successful revision to a total hip arthroplasty because of femoral neck fracture (2), femoral loosening, or infection. The Kaplan-Meier survivorship was 97%. Acetabular bone conservation was assessed using computed tomography by measuring the medial acetabular wall. The mean thickness was 9 mm. Femoral bone was well preserved with a mean head:neck ratio of 1.37. There were 4 (2%) osteolytic defects up to 0.9 cm(3) on computed tomography and no instances of impending polyethylene wear-through. Seven polyethylene retrievals had a measured wear rate of 0.05 mm/y. Hip resurfacing using a highly cross-linked polyethylene acetabular component is a reliable procedure. Both femoral and acetabular bones are reasonably preserved compared with prior resurfacing methods. The low incidence of osteolysis and the low rate of wear found on retrievals suggest that many years of use in highly active patients is possible. Copyright © 2016 Elsevier Inc. All rights reserved.

High complication rate in reconstruction of Paprosky type IIIa acetabular defects using an oblong implant with modular side plates and a hook.

PubMed

Babis, G C; Sakellariou, V I; Chatziantoniou, A N; Soucacos, P N; Megas, P

2011-12-01

We report the results of 62 hips in 62 patients (17 males, 45 females) with mean age of 62.4 years (37 to 81), who underwent revision of the acetabular component of a total hip replacement due to aseptic loosening between May 2003 and November 2007. All hips had a Paprosky type IIIa acetabular defect. Acetabular revision was undertaken using a Procotyl E cementless oblong implant with modular side plates and a hook combined with impaction allografting. At a mean follow-up of 60.5 months (36 to 94) with no patients lost to follow-up and one died due to unrelated illness, the complication rate was 38.7%. Complications included aseptic loosening (19 hips), deep infection (3 hips), broken hook and side plate (one hip) and a femoral nerve palsy (one hip). Further revision of the acetabular component was required in 18 hips (29.0%) and a further four hips (6.4%) are currently loose and awaiting revision. We observed unacceptably high rates of complication and failure in our group of patients and cannot recommend this implant or technique.

A New Automated Way to Measure Polyethylene Wear in THA Using a High Resolution CT Scanner: Method and Analysis

PubMed Central

Maguire Jr., Gerald Q.; Noz, Marilyn E.; Olivecrona, Henrik; Zeleznik, Michael P.

2014-01-01

As the most advantageous total hip arthroplasty (THA) operation is the first, timely replacement of only the liner is socially and economically important because the utilization of THA is increasing as younger and more active patients are receiving implants and they are living longer. Automatic algorithms were developed to infer liner wear by estimating the separation between the acetabular cup and femoral component head given a computed tomography (CT) volume. Two series of CT volumes of a hip phantom were acquired with the femoral component head placed at 14 different positions relative to the acetabular cup. The mean and standard deviation (SD) of the diameter of the acetabular cup and femoral component head, in addition to the range of error in the expected wear values and the repeatability of all the measurements, were calculated. The algorithms resulted in a mean (±SD) for the diameter of the acetabular cup of 54.21 (±0.011) mm and for the femoral component head of 22.09 (±0.02) mm. The wear error was ±0.1 mm and the repeatability was 0.077 mm. This approach is applicable clinically as it utilizes readily available computed tomography imaging systems and requires only five minutes of human interaction. PMID:24587727

Can Arthroplasty Stem INfluence Outcome? (CASINO): a randomized controlled equivalence trial of 125 mm versus 150 mm Exeter V40 stems in total hip arthroplasty.

PubMed

Hamilton, David F; Ohly, Nicholas E; Gaston, Paul

2018-04-16

The use of shorter length femoral stems during total hip arthroplasty has been suggested to accommodate wider patient femoral geometry and offer maximal bone preservation. However, cemented short-stem designs may increase the risk of varus stem malalignment and influence patient outcomes. CASINO is a multi-centre randomised equivalence trial that will recruit 220 patients undergoing total hip arthroplasty for osteoarthritis at two NHS hospitals in Scotland. Patients will be aged 45-80, undergoing unilateral primary hip arthroplasty, with no plan for contralateral procedure within the study timeframe, and able to comply with the protocol. Participants will be randomised to receive either a short (125 mm) or a standard (150 mm) Exeter V40 stem. The Contemporary acetabular component will be used in all cases. All implants will be cemented. Patient pain, function and satisfaction will be assessed using change from baseline measurement in Oxford Hip Score, Forgotten Joint Score, EQ-5D, pain numerical rating scores, and patient satisfaction questionnaire at baseline and at 1 and 2 years following surgery. Radiographic assessment will evaluate stem position and will be appraised by independent reviewers. Patients will be blind to implant allocation. Stem length may be associated with outcome; however, we can find no randomised trial in which researchers investigated the effect of stem length on patient outcome following cemented total hip arthroplasty. The aim of this trial is to determine if the use of short cemented stems offers equivalent patient outcomes to those achieved following surgery with standard length stems. International Standard Randomised Controlled Trial Number, ISRCTN13154542 , Registered on 30 June 2017.

Long-term results of uncemented alumina acetabular implants.

PubMed

Boehler, M; Knahr, K; Plenk, H; Walter, A; Salzer, M; Schreiber, V

1994-01-01

We report the clinical and tribological performance of 67 ceramic acetabular prostheses implanted between 1976 and 1979 without bone cement. They articulated with ceramic femoral heads mounted on mental femoral stems. After a mean elapsed period of 144 months, 59 sockets were radiographically stable but two showed early signs and six showed late signs of loosening. Four of the loose sockets have been revised. Histological analysis of the retrieved tissue showed a fibrous membrane around all the implants, with fibrocartilage in some. There was no bone ingrowth, and the fibrous membrane was up to 6 mm thick and infiltrated with lymphocytes, plasma cells, and macrophages. Intra- and extracellular birefringent wear particles were seen. Tribological analysis showed total wear rates in two retrieved alumina-on-alumina joints of 2.6 microns per year in a stable implant and 68 microns in a loose implant. Survival analysis showed a revision rate of 12.4% at 136 months.

Acetabular revisions using porous tantalum components: A retrospective study with 5-10 years follow-up

PubMed Central

Evola, Francesco Roberto; Costarella, Luciano; Evola, Giuseppe; Barchitta, Martina; Agodi, Antonella; Sessa, Giuseppe

2017-01-01

AIM To evaluate the clinical and X-ray results of acetabular components and tantalum augments in prosthetic hip revisions. METHODS Fifty-eight hip prostheses with primary failure of the acetabular component were reviewed with tantalum implants. The clinical records and X-rays of these cases were retrospectively reviewed. Bone defect evaluations were based on preoperative CT scans and classified according to Paprosky criteria of Radiolucent lines and periprosthetic gaps; implant mobilization and osteolysis were evaluated by X-ray. An ad hoc database was created and statistical analyses were performed with SPSS software (IBM SPSS Statistics for Windows, version 23.0). Statistical analyses were carried out using the Student’s t test for independent and paired samples. A P value of < 0.05 was considered statistically significant and cumulative survival was calculated by the Kaplan-Meier method. RESULTS The mean follow-up was 87.6 ± 25.6 mo (range 3-120 mo). 25 cases (43.1%) were classified as minor defects, and 33 cases (56.9%) as major defects. The preoperative HHS rating improved significantly from a mean of 40.7 ± 6.1 (range: 29-53) before revision, to a mean of 85.8 ± 6.1 (range: 70-94) at the end of the follow-up (Student’s t test for paired samples: P < 0.001). Considering HHS only at the end of follow-up, no statistically significant difference was observed between patients with a major or minor defect (Student’s t test for independent samples: P > 0.05). Radiolucent lines were found in 4 implants (6.9%). Postoperative acetabular gaps were observed in 5 hips (8.6%). No signs of implant mobilization or areas of periprosthetic osteolysis were found in the x-rays at the final follow-up. Only 3 implants failed: 1 case of infection and 2 cases of instability. Defined as the end-point, cumulative survival at 10 years was 95% (for all reasons) and 100% for aseptic loosening of the acetabular component. CONCLUSION The medium-term use of prosthetic tantalum components in prosthetic hip revisions is safe and effective in a wide variety of acetabular bone defects. PMID:28808626

Acetabular revisions using porous tantalum components: A retrospective study with 5-10 years follow-up.

PubMed

Evola, Francesco Roberto; Costarella, Luciano; Evola, Giuseppe; Barchitta, Martina; Agodi, Antonella; Sessa, Giuseppe

2017-07-18

To evaluate the clinical and X-ray results of acetabular components and tantalum augments in prosthetic hip revisions. Fifty-eight hip prostheses with primary failure of the acetabular component were reviewed with tantalum implants. The clinical records and X-rays of these cases were retrospectively reviewed. Bone defect evaluations were based on preoperative CT scans and classified according to Paprosky criteria of Radiolucent lines and periprosthetic gaps; implant mobilization and osteolysis were evaluated by X-ray. An ad hoc database was created and statistical analyses were performed with SPSS software (IBM SPSS Statistics for Windows, version 23.0). Statistical analyses were carried out using the Student's t test for independent and paired samples. A P value of < 0.05 was considered statistically significant and cumulative survival was calculated by the Kaplan-Meier method. The mean follow-up was 87.6 ± 25.6 mo (range 3-120 mo). 25 cases (43.1%) were classified as minor defects, and 33 cases (56.9%) as major defects. The preoperative HHS rating improved significantly from a mean of 40.7 ± 6.1 (range: 29-53) before revision, to a mean of 85.8 ± 6.1 (range: 70-94) at the end of the follow-up (Student's t test for paired samples: P < 0.001). Considering HHS only at the end of follow-up, no statistically significant difference was observed between patients with a major or minor defect (Student's t test for independent samples: P > 0.05). Radiolucent lines were found in 4 implants (6.9%). Postoperative acetabular gaps were observed in 5 hips (8.6%). No signs of implant mobilization or areas of periprosthetic osteolysis were found in the x-rays at the final follow-up. Only 3 implants failed: 1 case of infection and 2 cases of instability. Defined as the end-point, cumulative survival at 10 years was 95% (for all reasons) and 100% for aseptic loosening of the acetabular component. The medium-term use of prosthetic tantalum components in prosthetic hip revisions is safe and effective in a wide variety of acetabular bone defects.

The relationship between operative and radiographic acetabular component orientation: which factors influence resultant cup orientation?

PubMed

Grammatopoulos, G; Pandit, H G; da Assunção, R; McLardy-Smith, P; De Smet, K A; Gill, H S; Murray, D W

2014-10-01

There is great variability in acetabular component orientation following hip replacement. The aims of this study were to compare the component orientation at impaction with the orientation measured on post-operative radiographs and identify factors that influence the difference between the two. A total of 67 hip replacements (52 total hip replacements and 15 hip resurfacings) were prospectively studied. Intra-operatively, the orientation of the acetabular component after impaction relative to the operating table was measured using a validated stereo-photogrammetry protocol. Post-operatively, the radiographic orientation was measured; the mean inclination/anteversion was 43° (sd 6°)/ 19° (sd 7°). A simulated radiographic orientation was calculated based on how the orientation would have appeared had an on-table radiograph been taken intra-operatively. The mean difference between radiographic and intra-operative inclination/anteversion was 5° (sd 5°)/ -8° (sd 8°). The mean difference between simulated radiographic and intra-operative inclination/anteversion, which quantifies the effect of the different way acetabular orientation is measured, was 3°/-6° (sd 2°). The mean difference between radiographic and simulated radiographic orientation inclination/anteversion, which is a manifestation of the change in pelvic position between component impaction and radiograph, was 1°/-2° (sd 7°). This study demonstrated that in order to achieve a specific radiographic orientation target, surgeons should implant the acetabular component 5° less inclined and 8° more anteverted than their target. Great variability (2 sd about ± 15°) in the post-operative radiographic cup orientation was seen. The two equally contributing causes for this are variability in the orientation at which the cup is implanted, and the change in pelvic position between impaction and post-operative radiograph. ©2014 The British Editorial Society of Bone & Joint Surgery.

Does oversizing an uncemented cup increase post-operative pain in primary total hip arthroplasty?

PubMed

Barrow, Jonathan A; Divecha, Hiren M; Panchani, Sunil; Boden, Richard; Porter, Martyn L; Board, Tim N

2018-05-31

It has been suggested that one of the factors related to persistent post-operative pain following total hip arthroplasty (THA) is to over sizing of the acetabular component. In order to investigate this potential issue, we retrospectively analysed a series of consecutive uncemented THA. We assessed the incidence of persistent post-operative pain and the size difference between the implanted acetabular component and the native femoral head. A total of 265 consecutive THAs were retrospectively identified. Standardised pre-operative radiographs were analysed using validated techniques to determine the native femoral head diameter. Post-operative standardised radiographs were reviewed and the acetabular orientation determined. Patients were sent postal questionnaires regarding their outcome and level of pain. Questionnaires were returned by 169 patients (189 hips, 71% response rate). A total of 17 were excluded due to inadequate radiographs., leaving 172 THA in the study group. The mean native femoral head (NFH) size was 47 mm. The most common implanted acetabular component size was 52 mm. The mean difference in cup to NFH diameter (delta) was 5.7 mm (range - 6.1 to 15.4 mm; 95% CI 5.3-6.2 mm). A delta of > 6 mm was found to be significant for predicting persistent post-operative pain (RR = 1.81; 95% CI 1.1-3.1; P = 0.027). Our study confirms that a delta of > 6 mm is associated with an increased risk of persistent post-operative pain following THA. We recommend pre-operative templating in all uncemented THA to ensure the planned acetabular component is no more than 6 mm larger than the NFH diameter.

Pain Palliation by Percutaneous Acetabular Osteoplasty for Metastatic Hepatocellular Carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hokotate, Hirofumi; Baba, Yasutaka; Churei, Hisahiko

2001-09-15

A 68-year-old man with hepatocellular carcinoma and known skeletal metastasis developed right hip pain and gait disturbance due to an osteolytic metastasis in the right acetabulum. This was treated initially with chemoembolization and radiation therapy. When these procedures proved unsuccessful percutaneous injection of acrylic bone cement into the acetabulum was undertaken. Immediately after this procedure, he obtained sufficient pain relief and improved walking ability, which continued for 3 months until he died of hepatic insufficiency.

An unusual mode of failure of a tripolar constrained acetabular liner: a case report.

PubMed

Banks, Louisa N; McElwain, John P

2010-04-01

Dislocation after primary total hip arthroplasty (THA) is the most commonly encountered complication and is unpleasant for both the patient and the surgeon. Constrained acetabular components can be used to treat or prevent instability after primary total hip arthroplasty. We present the case of a 42-year-old female with a BMI of 41. At 18 months post-primary THA the patient underwent further revision hip surgery after numerous (more than 20) dislocations. She had a tripolar Trident acetabular cup (Stryker-Howmedica-Osteonics, Rutherford, New Jersey) inserted. Shortly afterwards the unusual mode of failure of the constrained acetabular liner was noted from radiographs in that the inner liner had dissociated from the outer. The reinforcing ring remained intact and in place. We believe that the patient's weight, combined with poor abductor musculature caused excessive demand on the device leading to failure at this interface when the patient flexed forward. Constrained acetabular components are useful implants to treat instability but have been shown to have up to 42% long-term failure rates with problems such as dissociated inserts, dissociated constraining rings and dissociated femoral rings being sited. Sometimes they may be the only option left in difficult cases such as illustrated here, but still unfortunately have the capacity to fail in unusual ways.

In vivo implant fixation of carbon fiber-reinforced PEEK hip prostheses in an ovine model.

PubMed

Nakahara, Ichiro; Takao, Masaki; Bandoh, Shunichi; Bertollo, Nicky; Walsh, William R; Sugano, Nobuhiko

2013-03-01

Carbon fiber-reinforced polyetheretherketone (CFR/PEEK) is theoretically suitable as a material for use in hip prostheses, offering excellent biocompatibility, mechanical properties, and the absence of metal ions. To evaluate in vivo fixation methods of CFR/PEEK hip prostheses in bone, we examined radiographic and histological results for cementless or cemented CFR/PEEK hip prostheses in an ovine model with implantation up to 52 weeks. CFR/PEEK cups and stems with rough-textured surfaces plus hydroxyapatite (HA) coatings for cementless fixation and CFR/PEEK cups and stems without HA coating for cement fixation were manufactured based on ovine computed tomography (CT) data. Unilateral total hip arthroplasty was performed using cementless or cemented CFR/PEEK hip prostheses. Five cementless cups and stems and six cemented cups and stems were evaluated. On the femoral side, all cementless stems demonstrated bony ongrowth fixation and all cemented stems demonstrated stable fixation without any gaps at both the bone-cement and cement-stem interfaces. All cementless cases and four of the six cemented cases showed minimal stress shielding. On the acetabular side, two of the five cementless cups demonstrated bony ongrowth fixation. Our results suggest that both cementless and cemented CFR/PEEK stems work well for fixation. Cup fixation may be difficult for both cementless and cemented types in this ovine model, but bone ongrowth fixation on the cup was first seen in two cementless cases. Cementless fixation can be achieved using HA-coated CFR/PEEK implants, even under load-bearing conditions. Copyright © 2012 Orthopaedic Research Society.

What Safe Zone? The Vast Majority of Dislocated THAs Are Within the Lewinnek Safe Zone for Acetabular Component Position.

PubMed

Abdel, Matthew P; von Roth, Philipp; Jennings, Matthew T; Hanssen, Arlen D; Pagnano, Mark W

2016-02-01

Numerous factors influence total hip arthroplasty (THA) stability including surgical approach and soft tissue tension, patient compliance, and component position. One long-held tenet regarding component position is that cup inclination and anteversion of 40° ± 10° and 15° ± 10°, respectively, represent a "safe zone" as defined by Lewinnek that minimizes dislocation after primary THA; however, it is clear that components positioned in this zone can and do dislocate. We sought to determine if these classic radiographic targets for cup inclination and anteversion accurately predicted a safe zone limiting dislocation in a contemporary THA practice. From a cohort of 9784 primary THAs performed between 2003 and 2012 at one institution, we retrospectively identified 206 THAs (2%) that subsequently dislocated. Radiographic parameters including inclination, anteversion, center of rotation, and limb length discrepancy were analyzed. Mean followup was 27 months (range, 0-133 months). The majority (58% [120 of 206]) of dislocated THAs had a socket within the Lewinnek safe zone. Mean cup inclination was 44° ± 8° with 84% within the safe zone for inclination. Mean anteversion was 15° ± 9° with 69% within the safe zone for anteversion. Sixty-five percent of dislocated THAs that were performed through a posterior approach had an acetabular component within the combined acetabular safe zones, whereas this was true for only 33% performed through an anterolateral approach. An acetabular component performed through a posterior approach was three times as likely to be within the combined acetabular safe zones (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.1-1.6) than after an anterolateral approach (OR, 0.4; 95% CI, 0.2-0.7; p < 0.0001). In contrast, acetabular components performed through a posterior approach (OR, 1.6; 95% CI, 1.2-1.9) had an increased risk of dislocation compared with those performed through an anterolateral approach (OR, 0.8; 95% CI, 0.7-0.9; p < 0.0001). The historical target values for cup inclination and anteversion may be useful but should not be considered a safe zone given that the majority of these contemporary THAs that dislocated were within those target values. Stability is likely multifactorial; the ideal cup position for some patients may lie outside the Lewinnek safe zone and more advanced analysis is required to identify the right target in that subgroup. Level III, therapeutic study.

Robotic-arm assisted total hip arthroplasty results in smaller acetabular cup size in relation to the femoral head size: a matched-pair controlled study.

PubMed

Suarez-Ahedo, Carlos; Gui, Chengcheng; Martin, Timothy J; Chandrasekaran, Sivashankar; Lodhia, Parth; Domb, Benjamin G

2017-03-31

To compare the acetabular component size relative to the patient's native femoral head size between conventional THA (CTHA) approach and robotic-arm assisted THA (RTHA) to infer which of these techniques preserved more acetabular bone. Patients were included if they had primary osteoarthritis (OA) and underwent total hip replacement between June 2008 and March 2014. Patients were excluded if they had missing or rotated postoperative anteroposterior radiographs. RTHA patients were matched to a control group of CTHA patients, in terms of preoperative native femoral head size, age, gender, body mass index (BMI) and approach. Acetabular cup size relative to femoral head size was used as a surrogate for amount of bone resected. We compared the groups according to 2 measures describing acetabular cup diameter (c) in relation to femoral head diameter (f): (i) c-f, the difference between cup diameter and femoral head diameter and (ii) (c-f)/f, the same difference as a fraction of femoral head diameter. 57 matched pairs were included in each group. There were no significant differences between groups for demographic measures, femoral head diameter, or acetabular cup diameter (p>0.05). However, measures (i) and (ii) did differ significantly between the groups, with lower values in the RTHA group (p<0.02). Using acetabular cup size relative to femoral head size as an approximate surrogate measure of acetabular bone resection may suggest greater preservation of bone stock using RTHA compared to CTHA. Further studies are needed to validate the relationship between acetabular cup size and bone loss in THA.

Metallic wear in failed titanium-alloy total hip replacements. A histological and quantitative analysis.

PubMed

Agins, H J; Alcock, N W; Bansal, M; Salvati, E A; Wilson, P D; Pellicci, P M; Bullough, P G

1988-03-01

We conducted extensive histological examination of the tissues that were adjacent to the prosthesis in nine hips that had a failed total arthroplasty. The prostheses were composed of titanium alloy (Ti-6Al-4V) and ultra-high molecular weight polyethylene. The average time that the prosthesis had been in place in the tissue was 33.5 months (range, eleven to fifty-seven months). Seven arthroplasties were revised because of aseptic loosening and two, for infection. In eight hips cement had been used and in one (that had a porous-coated implant for fifty-two months) no cement had been utilized. Intense histiocytic and plasma-cell reaction was noted in the pseudocapsular tissue. There was copious metallic staining of the lining cells. Polyethylene debris and particles of cement with concomitant giant-cell reaction were present in five hips. Atomic absorption spectrophotometry revealed values for titanium of fifty-sic to 3700 micrograms per gram of dry tissue (average, 1047 micrograms per gram; normal, zero microgram per gram), for aluminum of 2.1 to 396 micrograms per gram (average, 115 micrograms per gram; normal, zero micrograms per gram), and for vanadium of 2.9 to 220 micrograms per gram (average, sixty-seven micrograms per gram; normal, 1.2 micrograms per gram). The highest values were found in the hip in which surgical revision was performed at fifty-seven months. The concentrations of the three elements in the soft tissues were similar to those in the metal of the prostheses. The factors to which failure was attributed were: vertical orientation of the acetabular component (five hips), poor cementing technique on the femoral side (three hips), infection (two hips), and separation of a sintered pad made of pure titanium (one hip). A femoral component that is made of titanium alloy can undergo severe wear of the surface and on the stem, where it is loose, with liberation of potentially toxic local concentrations of metal debris into the surrounding tissues. It may contribute to infection and loosening.

Application of Rapid Prototyping Pelvic Model for Patients with DDH to Facilitate Arthroplasty Planning: A Pilot Study.

PubMed

Xu, Jie; Li, Deng; Ma, Ruo-fan; Barden, Bertram; Ding, Yue

2015-11-01

Total hip arthroplasty (THA) is challenging in cases of osteoarthritis secondary to developmental dysplasia of the hip (DDH). Acetabular deficiency makes the positioning of the acetabular component difficult. Computer tomography based, patient-individual three dimensional (3-D) rapid prototype technology (RPT)-models were used to plan the placement of acetabular cup so that a surgeon was able to identify pelvic structures, assess the ideal extent of reaming and determine the size of cup after a reconstructive procedure. Intraclass correlation coefficients (ICCs) were used to analyze the agreement between the sizes of chosen components on the basis of preoperative planning and the actual sizes used in the operation. The use of the 3-D RPT-model facilitates the surgical procedures due to better planning and improved orientation. Copyright © 2015 Elsevier Inc. All rights reserved.

Fire and ice: percutaneous ablative therapies and cement injection in management of metastatic disease of the spine.

PubMed

Munk, Peter L; Murphy, Kieran J; Gangi, Afshin; Liu, David M

2011-04-01

Oncology intervention is actively moving beyond simple bone cement injection. Archimedes taught us that a volume displaces its volume. Where does the tumor we displace with our cement injection go? It is no longer acceptable that we displace tumor into the venous system with our cement injections. We must kill the tumor first. Different image-guided percutaneous techniques can be used for treatment in patients with primary or secondary bone tumors. Curative ablation can be applied for the treatment of specific benign or in selected cases of malignant localized spinal tumors. Pain palliation therapy of primary and secondary bone tumors can be achieved with safe, fast, effective, and tolerable percutaneous methods. Ablation (chemical, thermal, mechanical), cavitation (radiofrequency ionization), and consolidation (cementoplasty) techniques can be used separately or in combination. Each technique has its indications, with both advantages and drawbacks. To prevent pathological fractures, a consolidation is necessary. In spinal or acetabular tumors, a percutaneous cementoplasty should be associated with cryoablation to avoid a compression fracture. The cement is injected after complete thawing of the ice ball or the day after the cryotherapy. A syndrome of multiorgan failure, severe coagulopathy, and disseminated intravascular coagulation following hepatic cryoablation has been described and is referred to as the cryoshock phenomenon. © Thieme Medical Publishers.

[Tripolar arthroplasty for recurrent total hip prosthesis dislocation].

PubMed

Beaulé, P-E; Roussignol, X; Schmalzried, T-P; Udomkiat, P; Amstutz, H-C; Dujardin, F-H

2003-05-01

The purpose of this study was to assess the results of revision surgery for recurrent total hip prosthesis dislocation using a tripolar prosthesis composed of a conventional stem with a mobile head of an intermediary prosthesis measuring more than 40 mm and a modified cup. This technique was used in two centers in Rouen France and Los Angeles USA. Twenty-one hips in 21 patients were operated on. The mobile heads measured 40 to 47 mm. Mean patient age was 70 years (range 29-92). The indication for the tripolar prosthesis was reserved for extremely unstable hips in patients with major risk factors for recurrent dislocation. These 21 patients had experienced 95 dislocations. The acetabular cup was custom-made for the large-diameter heads. A cemented polyethylene cup was used in 14 cases and a press-fit metal-backed around a polyethylene insert in 7. The polyethylene thickness varied from 6.5 to 16 mm for the cemented cups and 4 to 5 mm for the press-fit cups. Fourteen femoral stems were left in place as were two press-fit cups where only the inserts were changed. Mean follow-up was 5.4 years (range 3-11.8). There has been no recurrent dislocation for 20 hips. One patient experienced a dislocation one week after surgery which required a second revision procedure to reposition the acetabular implant. Final outcome was good at 7.6 years for this hip. One patient who had not had any recurrent dislocation died 4 years after the revision surgery due to a cause unrelated to the prosthesis. Two patients were lost to follow-up at 3.7 and 6 years, both were pain free and had no radiological anomalies. Infection occurred in one patient undergoing chemotherapy for a myeloma; the head and neck had to be resected. For the 20 other patients, functional outcome, assessed with the UCLA score, showed improvement in pain (5.8 preoperatively, 9.2 at last follow-up), walking (4.8 and 8 respectively), function (4 and 6 respectively), and daily activities (3.3 and 5.2 respectively). A revision procedure was necessary for one patient during the 4(th) year because of a fracture of the polyethylene insert on a metal-back cup; the insert alone was changed. Excepting the patient with infection, there were no cases of certain or probable loosening during the follow-up. The tripolar prosthesis with a mobile cup and a large-diameter head appears to be a reliable solution for these severely unstable hips. The procedure can often be limited to the acetabular component, reducing morbidity. The thickness of the polyethylene cup is a limitation which may affect long-term survival. Search for a highly wear-resistant couple continues.

Aseptic loosening of cobalt chromium monoblock sockets after hip resurfacing.

PubMed

Amstutz, Harlan C; Le Duff, Michel J

2015-01-01

Acetabular component loosening is a leading cause for revision after metal-on-metal hip resurfacing arthroplasty (MMHRA). We aimed to identify potential risk factors and determine radiographic signs associated with this mode of failure. From a series of 1375 hips treated with MMHRA, 21 (20 patients) underwent revision surgery secondary to aseptic loosening of the acetabular component and 6 patients had a radiographically loose acetabular component. A control group of 27 hips (26 patients) was selected among the patients that did not have a revision, and was matched for age, gender, component size and diagnosis. Mean time to revision in the loosening group was 103.0 months and the mean time of follow-up in the control group was 161.4 months. We found greater activity levels, range of motion scores, and cup abduction angles in the loosening group. The centre-edge (CE) angle of Wiberg was 10° lower in the loosening group compared with the control group. In addition, 11 of the hips from the study group presented a sclerotic halo superior to the cup on the last radiograph vs. none in the control group. There was no difference in the prevalence of postoperative reaming gaps or radiographic signs of neck-cup impingement between the 2 groups. Risk factors for acetabular loosening included hip dysplasia with low CE angle, and a large cup abduction angle. The patient's level of activity influences the appearance of symptoms and the time to revision. We recommend selecting patients with a sufficient CE angle and properly orienting the cup.

Gamma inert sterilization: a solution to polyethylene oxidation?

PubMed

Medel, Francisco J; Kurtz, Steven M; Hozack, William J; Parvizi, Javad; Purtill, James J; Sharkey, Peter F; MacDonald, Daniel; Kraay, Matthew J; Goldberg, Victor; Rimnac, Clare M

2009-04-01

In the 1990s, oxidation was found to occur in ultra-high molecular weight polyethylene total joint replacement components following gamma irradiation and prolonged shelf aging in air. Orthopaedic manufacturers developed barrier packaging to reduce oxidation during and after radiation sterilization. The present study explores the hypothesis that polyethylene components sterilized in a low-oxygen environment undergo similar in vivo oxidative mechanisms as inserts sterilized in air. In addition, the potential influence of the different sterilization processes on the wear performance of the polyethylene components was examined. An analysis of oxidation, wear, and surface damage was performed for forty-eight acetabular liners and 123 tibial inserts. The mean implantation time was 12.3+/-3.7 years for thirty-one acetabular liners that had been gamma sterilized in air and 4.0+/-2.5 years for the seventeen acetabular liners that had been gamma sterilized in inert gas. The mean implantation time was 11.0+/-3.2 years for the twenty-six tibial inserts that had been sterilized in air and 2.8+/-2.2 years for the ninety-seven tibial inserts that had been gamma sterilized in inert gas. Oxidation and hydroperoxide levels were characterized in loaded and unloaded regions of the inserts. Measurable oxidation and oxidation potential were observed in all cohorts. The oxidation and hydroperoxide levels were regional. Surfaces with access to body fluids were more heavily oxidized than protected bearing surfaces were. This variation appeared to be greater in historical (gamma-in-air-sterilized) components. Regarding wear performance, historical and conventional acetabular liners showed similar wear penetration rates, whereas a low incidence of delamination was confirmed for the conventional tibial inserts in the first decade of implantation. The present study explores the impact of industry-wide changes in sterilization practices for polyethylene. We found lower oxidation and oxidation potential in the conventional acetabular liners and tibial inserts that had been gamma sterilized in inert gas as compared with the historical components that had been gamma sterilized in air. However, we also found strong evidence that conventional components undergo mechanisms of in vivo oxidation similar to those observed following gamma irradiation in air. In addition, gamma sterilization in inert gas did not provide polyethylene with a significant improvement in terms of wear resistance as compared with gamma sterilization in air, except for a lower incidence of delamination in the first decade of implantation for tibial inserts.

[Poldi-Čech cemented femoral stem in total hip arthroplasty after 25 years].

PubMed

Rozkydal, Z; Janíček, P

2010-08-01

The aim of the study was to evaluate the results of Poldi-Čech femoral stem implantation in primary total hip arthroplasty after 25 years. A group of 65 patients (90 hips) with Poldi-Čech total hip arthroplasty carried out between 1974 and 1984 was evaluated at the end of 2009. The mean follow-up of all patients was 28 years (25 to 35). There were seven men and 58 women. The mean age at the time of implantation was 43 years (26 to 60) and at the latest follow-up it was 72 years. In all patients the cemented UHMW PE acetabular component (RCH 1000) was used together with AKV Ultra 2 Poldi steel femoral stems (1st, 2nd and 3rd generations). The stem was a monoblock with a 32-mm head. The evaluation of the results was based on the Harris hip score and X ray with an A-P view of the pelvis and the affected hip. Statistical analysis was made using the life-table method. At the latest follow up the mean Harris score was 69.7 points (40 to 88). There were 69 hips with an original Poldi-Čech femoral component still in situ, 64 of them were stable and five with radiological evidence of aseptic loosening. Five patients had undergone Girdlestone resection arthroplasty for septic loosening. Thirteen patients (16 hips) had femoral stem revision. The cumulative proportion of clinical survivorship of the Poldi-Čech femoral stem, with revision for any reason as the endpoint, .was 0.93 at 6 years, 0.84 at 12 years, and 0.77 at 18, 24 and 30 years after the index surgery. Radiographic findings revealed 64 hips with stable stems, five hips with ;aseptic loosening (probable, 0 possible, 2, definite, 3). Six- teen hips were after revision surgery for aseptic loosening of the stem and five hips were after Girdlestone resection arthroplasty for septic failure. The cumulative proportion of radiological survivorship of the Poldi-Čech femoral stem with any reason as the endpoint was 0.92 at 6 years, 0.78 at 12 years, 0.72 at 18 years, 0.69 at 24 years and 0.69 at 30 years. The Poldi-Čech stem with its anatomical shape and a highly polished surface meets the principles of successful composite beam stems. Its disadvantage is a valgus neck- shaft angle of 140° giving lower femoral offset and the risk of development of valgus deformity of the ipsilateral knee. In most cases osteolysis, radiolucent lines and bone rarefaction of the femur resulted from polyethylene wear of the acetabular component. This study demonstrates a long-term survivorship of the Poldi-Čech femoral component in patients undergoing total hip arthroplasty 25 to 35 years ago.

Effect of screw fixation on acetabular component alignment change in total hip arthroplasty.

PubMed

Fujishiro, Takaaki; Hayashi, Shinya; Kanzaki, Noriyuki; Hashimoto, Shingo; Shibanuma, Nao; Kurosaka, Masahiro

2014-06-01

The use of screws can enhance immediate cup fixation, but the influence of screw insertion on cup position has not previously been measured. The purpose of this study was to quantitatively evaluate the effect of intra-operative screw fixation on acetabular component alignment that has been inserted with the use of a navigation system. We used a navigation system to measure cup alignment at the time of press-fit and after screw fixation in 144 hips undergoing total hip arthroplasty. We also compared those findings with factors measured from postoperative radiographs. The mean intra-operative change of cup position was 1.78° for inclination and 1.81° for anteversion. The intra-operative change of anteversion correlated with the number of screws. The intra-operative change of inclination also correlated with medial hip centre. The insertion of screws can induce changes in cup alignment, especially when multiple screws are used or if a more medial hip centre is required for rigid acetabular fixation.

Endoscopic resection of acetabular screw tip to decompress sciatic nerve following total hip arthroplasty.

PubMed

Yoon, Sun-Jung; Park, Myung-Sik; Matsuda, Dean K; Choi, Yun Ho

2018-06-04

Sciatic nerve injuries following total hip arthroplasty are disabling complications. Although degrees of injury are variable from neuropraxia to neurotmesis, mechanical irritation of sciatic nerve might be occurred by protruding hardware. This case shows endoscopic decompression for protruded acetabular screw irritating sciatic nerve, the techniques described herein may permit broader arthroscopic/endoscopic applications for management of complications after reconstructive hip surgery. An 80-year-old man complained of severe pain and paresthesias following acetabular component revision surgery. Physical findings included right buttock pain with radiating pain to lower extremity. Radiographs and computed tomography imaging showed that the sharp end of protruded screw invaded greater sciatic foramen anterior to posterior and distal to proximal direction at sciatic notch level. A protruding tip of the acetabular screw at the sciatic notch was decompressed by use of techniques gained from experience performing endoscopic sciatic nerve decompression. The pre-operative pain and paresthesias resolved post-operatively after recovering from anesthesia. This case report describes the first documented endoscopic resection of the tip of the acetabular screw irritating sciatic nerve after total hip arthroplasty. If endoscopic resection of an offending acetabular screw can be performed in a safe and minimally invasive manner, one can envision a future expansion of the role of hip arthroscopic surgery in several complications management after total hip arthroplasty.

Modern dual-mobility cup implanted with an uncemented stem: about 100 cases with 12-year follow-up.

PubMed

Philippot, Remi; Meucci, Jean Francois; Boyer, Bertrand; Farizon, Frederic

2013-09-01

We report the results of a 12-year follow-up retrospective series of 100 total hip arthroplasties using cementless, press-fit, dual-mobility acetabular cups. The aim of our study was to evaluate the clinical and radiographic results of this acetabular cup at last follow-up. This continuous and homogeneous series included 100 primary total hip arthroplasties performed during the year 2000. The THA combined a Corail® stem (Corail®, Depuy, Warsaw, IN) with a stainless steel Novae Sunfit® (Serf, Decines, France) acetabular cup. Fifteen patients died and 2 were lost to follow-up. Two cases of early dislocation were observed, and 3 cases of aseptic loosening of the acetabular component were reported. The mean stem subsidence was 0.71 mm, the mean craniopodal acetabular migration was 1.37 mm, and the mean medio-lateral acetabular migration was 1.52 mm. The 12-year survivorship is comparable to the data from the literature. The low dislocation rate at 12 years confirms the long-term, high stability of dual mobility, which should be recommended in primary THA for patients at risk for postoperative instability. The absence of true intraprosthetic dislocation events at 12-year follow-up provides evidence of the good quality of the latest generation of polyethylene liners and the necessity of combining thin-mirror, polished femoral necks with dual-mobility cups.

Correlation of Cup Inclination Angle with Liner Wear for Metal-on-polyethylene in Hip Primary Arthroplasty.

PubMed

Tian, Jia-Liang; Sun, Li; Hu, Rui-Yin; Han, Wei; Tian, Xiao-Bin

2017-05-01

The relationship between cup inclination angle and liner wear is controversial. Most authors in the published literature agree that the ideal cup inclination is associated with lower inner wear; however, some disagree. All previous studies did not control for femoral head diameter and inclination, so it is difficult to assess the relative or synergistic effects of cup angle on outcomes. We retrospectively reviewed 154 patients (171 hips) with primary total hip arthroplasties performed from 2001 to 2004. All surgeries had been performed by the same physician team. A posterior approach was applied in all patients. All prostheses were non-cemented cups with a 28-mm metal head. Inclusion criteria included that the radiographic material was not completed or lost for primary or last follow up. Patients were divided into four groups according to different cup inclination angle. There were 108 hips with inclination angles below 50°; 35 hips with angles between 50° and 55°; 17 hips with angles between 55° and 60°; and 11 hips with angles greater than 60°. An immediate postoperative radiograph was compared with a follow-up radiograph. Clinical and radiographic data were collected on standardized hip evaluation forms preoperatively, 6 months after surgery and at yearly follow-up visits. Radiographs were digitized and enlarged 100%. After the radiographs were digitized, polyethylene wear rates and acetabular cup abduction were measured on all patients with Cavas 15.0 software. The results were analyzed using Student's two-tailed paired t-test with SPSS 11.5. The preoperative mean Harris hip score improved from 45.36 to 93.5 points 10 years after surgery. No acetabular component was revised for aseptic loosening. Three patients (three hips) had to undergo bone grafting and a lined arthroplasty for severe osteolysis around the acetabular component. The rate of implant survival at 10 years with respect to loosening was 100%. The mean liner wear rate was 0.135 mm/year in cups with inclination angles below 50°, 0.144 mm/year between 50° and 55°, 0.260 mm/year between 55° and 60°, and 0.403 mm/year when the angle was greater than 60°. Liner wear increased when the cup angle was larger than 55° (P < 0.05). For metal-on-polyethylene prostheses, liner wear correlates with cup inclination angle larger than 55°. The ideal abduction angle for metal-on-polyethylene prostheses is less than 55°. © 2017 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

Does using a polyethylene RM press-fit cup modify the preparation of the acetabulum and acetabular offset in primary hip arthroplasty?

PubMed

Erivan, R; Aubret, S; Villatte, G; Mulliez, A; Descamps, S; Boisgard, S

2017-09-01

When performing total hip arthroplasty (THA), it is important to maintain the femoral and acetabular offsets to ensure good joint stability and to restore the function of the hip abductor muscles. In our practice, we mainly use a lateralized stem and hollow out the acetabulum to the quadrilateral plate to accommodate a press-fit polyethylene cup. However, the repercussions of this preparation method, which is driven by the cup's design, are not known. We carried out a retrospective study to assess: (1) the changes in the femoral and acetabular offset; (2) the height of the center of rotation; and (3) the repercussions on wear. We hypothesized there would be no significant differences between the preoperative and postoperative femoral and acetabular offsets. We reviewed 88 primary THA cases performed with the RM Pressfit™ cup that had a minimum of 5 years' follow-up. A lateralized self-locking Muller-type cemented femoral stem was used in 92.0% of cases and a standard stem in 8.0%. Measurements were done on plain radiographs with MHP™ and Mesurim Pro™ software. The average follow-up was 6.5 years (5-8). On average, the acetabular offset was reduced by 2.75mm±5.9 mm (range: -17.5 to +10.6 mm) (P<0.001) and the femoral offset was increased by 0.01mm±5.5 mm (range: -17.8 to +11.0 mm) (P=0.99). In terms of total offset, medialization of 2.74mm±7 mm (range: -17.7 to +18.2mm) was found (P=0.001). The acetabular center of rotation was on average 4.77mm±5.1 mm higher (P<0.001). The mean annual wear at the more recent follow-up (min.: 5 years) was 0.068mm (range: 0.01 to 0.25mm) per year. The wear was not impacted by having more than 5mm change in offset. Measurements of acetabular offset revealed statistically significant medialization due to the type of implant used and the surgical technique. The anatomical technique consists of positioning the cup in subchondral bone without contacting the quadrilateral plate. This preserves bone stock, which may be useful later on if the cup is revised, particularly in younger patients. Conversely, the femoral offset did not change significantly, despite the use of lateralized stems in 92.0% of cases. We measured an annual wear rate of 0.068mm per year, which is lower than in other published studies, possibly because our patient population was older. IV, retrospective study. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

THA Using Metal-on-Metal Articulation in Active Patients Younger Than 50 Years

PubMed Central

Bonnomet, François; Clavert, Philippe; Laffargue, Philippe; Migaud, Henri

2008-01-01

The main concern of patients with longer life expectancies and of patients who are younger and more active is the longevity of their total hip arthroplasty. We retrospectively reviewed 83 cementless total hip arthroplasties in 73 patients implanted with metal-on-metal articulation. All patients were younger than 50 years old (average age, 41 years) at the time of the index procedure, and 80% of the patients had an activity level graded 4 or 5 when measured with the system of Devane et al. A 28-mm Metasul articulation was used with three different cementless titanium acetabular components. At the most recent followup (average, 7.3 years), the average Merle d’Aubigné-Postel score improved from a preoperative 11.1 points to 17.4 points. We observed no radiographic evidence of component loosening. Ten acetabular components had lucency limited to one zone. The 10-year survivorship with the end point of revision (ie, exchange of at least one prosthetic or bearing component) was 100% (95% confidence interval, 90%–100%). Metasul bearings with cementless acetabular components remain promising in this high-risk younger patient population. However, additional followup strategies are recommended to determine any possible long-term deleterious effects associated with the dissemination of metallic ions. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18196415

Serum Metal Ion Levels Following Total Hip Arthroplasty With Modular Dual Mobility Components.

PubMed

Matsen Ko, Laura J; Pollag, Kimberley E; Yoo, Joanne Y; Sharkey, Peter F

2016-01-01

Dual mobility acetabular components can reduce the incidence of total hip arthroplasty (THA) instability. Modular dual mobility (MDM) components facilitate acetabular component implantation. However, corrosion can occur at modular junctions. Serum cobalt and chromium levels and Oxford scores were obtained at minimum two year follow-up for 100 consecutive patients who had THA with MDM components. Average Oxford score was 43 (range 13-48). Average serum cobalt and chromium values were 0.7 mcg/L (range, 0.0 to 7.0) and 0.6 mcg/L (range, 0.1 to 2.7), respectively. MARS MRI was performed for four patients with pain and elevated serum cobalt levels. Two of these studies were consistent with adverse local tissue reaction. We recommend use of MDM implants in only patients at high risk for dislocation following THA. Copyright © 2016 Elsevier Inc. All rights reserved.

Measuring the migration of the components and polyethylene wear after total hip arthroplasty: beads and specialised radiographs are not necessary.

PubMed

Devane, P A; Horne, J G; Foley, G; Stanley, J

2017-10-01

This paper describes the methodology, validation and reliability of a new computer-assisted method which uses models of the patient's bones and the components to measure their migration and polyethylene wear from radiographs after total hip arthroplasty (THA). Models of the patient's acetabular and femoral component obtained from the manufacturer and models of the patient's pelvis and femur built from a single computed tomography (CT) scan, are used by a computer program to measure the migration of the components and the penetration of the femoral head from anteroposterior and lateral radiographs taken at follow-up visits. The program simulates the radiographic setup and matches the position and orientation of the models to outlines of the pelvis, the acetabular and femoral component, and femur on radiographs. Changes in position and orientation reflect the migration of the components and the penetration of the femoral head. Validation was performed using radiographs of phantoms simulating known migration and penetration, and the clinical feasibility of measuring migration was assessed in two patients. Migration of the acetabular and femoral components can be measured with limits of agreement (LOA) of 0.37 mm and 0.33 mm, respectively. Penetration of the femoral head can be measured with LOA of 0.161 mm. The migration of components and polyethylene wear can be measured without needing specialised radiographs. Accurate measurement may allow earlier prediction of failure after THA. Cite this article: Bone Joint J 2017;99-B:1290-7. ©2017 The British Editorial Society of Bone & Joint Surgery.

Tribological assessment of a flexible carbon-fibre-reinforced poly(ether-ether-ketone) acetabular cup articulating against an alumina femoral head.

PubMed

Scholes, S C; Inman, I A; Unsworth, A; Jones, E

2008-04-01

New material combinations have been introduced as the bearing surfaces of hip prostheses in an attempt to prolong their life by overcoming the problems of failure due to wear-particle-induced osteolysis. This will hopefully reduce the need for revision surgery. The study detailed here used a hip simulator to assess the volumetric wear rates of large-diameter carbon-fibre-reinforced pitch-based poly(ether-ether-ketone) (CFR-PEEK) acetabular cups articulating against alumina femoral heads. The joints were tested for 25 x 10(6) cycles. Friction tests were also performed on these joints to determine the lubrication regime under which they operate. The average volumetric wear rate of the CFR-PEEK acetabular component of 54 mm diameter was 1.16 mm(3)/10(6) cycles, compared with 38.6 mm(3)/10(6) cycles for an ultra-high-molecular-weight polyethylene acetabular component of 28 mm diameter worn against a ceramic head. This extremely low wear rate was sustained over 25 x 10(6) cycles (the equivalent of up to approximately 25 years in vivo). The frictional studies showed that the joints worked under the mixed-boundary lubrication regime. The low wear produced by these joints showed that this novel joint couple offers low wear rates and therefore may be an alternative material choice for the reduction of osteolysis.

Polyethylene wear debris in modular acetabular prostheses.

PubMed

Chen, P C; Mead, E H; Pinto, J G; Colwell, C W

1995-08-01

The longevity of total hip arthroplasty has brought forth the recognition of aseptic loosening of prosthetic components as the leading cause of implant failure. Modularity of implants, although a significant improvement in versatility, may increase debris formation, a recognized cause of implant failure. This study was designed to measure the relative motion, and to assess the polyethylene wear debris production at the interface between the metal acetabular shell and the back side of the polyethylene liner, in modular hip prostheses. Five models from 4 manufacturers with different locking mechanisms and acetabular shell surface treatments were tested under long-term simultaneous sinusoidal and static loading (10(7) cycles at 3 Hz with +/- 2.5 Nmeter and 220 N static load). Results showed that there were marked differences in the security of the acetabular shell and polyethylene liner locking mechanism, wear pattern, damage sites, and amount of polyethylene debris on the acetabular shell and polyethylene liner surfaces. The range of polyethylene liner motion observed among the 5 models during 1 cycle of testing varied from an average of 0.96 degrees to movement too small to be detected by the test machines. Image and scanning electron microscopy analysis showed different wear patterns and a wide range in the average polyethylene liner surface wear area (0.26 cm2-4.61 cm2). In general, a stable locking mechanism and a smooth acetabular shell surface are essential in minimizing polyethylene liner wear and polyethylene debris production.

Use of iPhone technology in improving acetabular component position in total hip arthroplasty.

PubMed

Tay, Xiau Wei; Zhang, Benny Xu; Gayagay, George

2017-09-01

Improper acetabular cup positioning is associated with high risk of complications after total hip arthroplasty. The aim of our study is to objectively compare 3 methods, namely (1) free hand, (2) alignment jig (Sputnik), and (3) iPhone application to identify an easy, reproducible, and accurate method in improving acetabular cup placement. We designed a simple setup and carried out a simple experiment (see Method section). Using statistical analysis, the difference in inclination angles using iPhone application compared with the freehand method was found to be statistically significant ( F [2,51] = 4.17, P = .02) in the "untrained group". There is no statistical significance detected for the other groups. This suggests a potential role for iPhone applications in junior surgeons in overcoming the steep learning curve.

Measuring acetabular component position on lateral radiographs - ischio-lateral method.

PubMed

Pulos, Nicholas; Tiberi Iii, John V; Schmalzried, Thomas P

2011-01-01

The standard method for the evaluation of arthritis and postoperative assessment of arthroplasty treatment is observation and measurement from plain films, using the flm edge for orientation. A more recent employment of an anatomical landmark, the ischial tuberosity, has come into use as orientation for evaluation and is called the ischio-lateral method. In this study, the use of this method was evaluated as a first report to the literature on acetabular component measurement using a skeletal reference with lateral radiographs. Postoperative radiographs of 52 hips, with at least three true lateral radiographs taken at different time periods, were analyzed. Component position was measured with the historical method (using the flm edge for orientation) and with the new method using the ischio-lateral method. The mean standard deviation (SD) for the historical approach was 3.7° and for the ischio-lateral method, 2.2° (p < 0.001). With the historical method, 19 (36.5%) hips had a SD greater than ± 4°, compared to six hips (11.5%) with the ischio-lateral method. By using a skeletal reference, the ischio-lateral method provides a more consistent measurement of acetabular component position. The high intra-class correlation coefficients for both intra- and inter-observer reliability indicate that the angle measured with this simple method, which employs no further technology, increased time, or cost, is consistent and reproducible for multiple observers.

Analysis of migration of press-fit porous-coated acetabular components with medial lucencies using Ein-Bild-Roentegen-Analyse.

PubMed

Sadeghi, Cameron; Gibson, Anthony G; Ries, Michael D

2012-08-01

A total of 136 patients who underwent total hip arthroplasty (154 hips) with press-fit acetabular components were evaluated for the presence of medial radiographic lucencies. Thirty patients (22.1%) demonstrated radiolucencies greater than 1 mm in zone 2 on initial postoperative films. Ein-Bild-Roentegen-Analyse (EBRA) was used to evaluate component migration over a 5-year follow-up period. Migration, measured by EBRA, was not observed during the first 6 months when the radiolucencies were noted to disappear. After 2 years, the mean total migration was 0.8 mm, and at 5 years, it was 1.6 mm. Our results indicate that disappearance of a medial radiolucency seen on early postoperative radiographs is not associated with component migration, which supports the concept that the medial radiolucency fills in with bone or represents bony remodeling around a stable implant. Copyright © 2012 Elsevier Inc. All rights reserved.

The effect of real-time aging on the oxidation and wear of highly cross-linked UHMWPE acetabular liners.

PubMed

Wannomae, Keith K; Christensen, Steven D; Freiberg, Andrew A; Bhattacharyya, Shayan; Harris, William H; Muratoglu, Orhun Kamil

2006-03-01

Irradiation decreases the wear of ultra-high molecular weight polyethylene (UHMWPE) but generates residual free radicals, precursors to long-term oxidation. Melting or annealing is used in quenching free radicals. We hypothesized that irradiated and once-annealed UHMWPE would oxidize while irradiated and melted UHMWPE would not, and that the oxidation in the former would increase wear. Acetabular liners were real-time aged by immersion in an aqueous environment that closely mimicked the temperature and oxygen concentration of synovial fluid. After 95 weeks of real-time aging, once-annealed components were oxidized; the melted components were not. The wear rate of the real-time aged irradiated and once-annealed components was higher than the literature reported values of other contemporary highly cross-linked UHMWPEs. Single annealing after irradiation used with terminal gamma sterilization may adversely affect the long-term oxidative stability of UHMWPE components.

Complications Are Not Increased With Acetabular Revision of Metal-on-metal Total Hip Arthroplasty.

PubMed

Penrose, Colin T; Seyler, Thorsten M; Wellman, Samuel S; Bolognesi, Michael P; Lachiewicz, Paul F

2016-10-01

Isolated revision of the acetabular component in the setting of total hip arthroplasty has an increased risk of dislocation. With local soft tissue destruction frequently associated with failed metal-on-metal (MoM) bearings, it is presumed that acetabular revision of these hips will have even greater risk of complications. However, no study directly compares the complications of MoM with metal-on-polyethylene (MoP) acetabular revisions. In the context of a large database analysis, we asked the following questions: (1) Are there differences in early medical or wound complications after isolated acetabular revision of MoM and MoP bearing surfaces? (2) Are there differences in the frequency of dislocation, deep infection, and rerevision based on the bearing surface of the original implant? A review of the 100% Medicare database from 2005 to 2012 was performed using International Classification of Diseases, 9th Revision and Current Procedural Terminology codes. We identified 451 patients with a MoM bearing and 628 patients with a MoP bearing who had an isolated acetabular revision and a minimum followup of 2 years. The incidence, odds ratios, and 95% confidence intervals for early medical or wound complications were calculated using a univariate analysis at 30 days with patient sex and age group-adjusted analysis for blood transfusion. The incidence, odds ratio, and 95% confidence intervals for dislocation, deep infection, and rerevision were calculated using a univariate analysis at 30 day, 90 days, 1 year, and 2 years using a subgroup analysis with the Cochran-Mantel-Haenszel test to adjust for patient gender and age groups. There were no differences between the MoM and MoP isolated acetabular revisions in the incidence of 30-day local complications. There was a greater risk of transfusion in the MoP group than the MoM group (134 of 451 [30%] versus 230 of 628 [37%]; odds ratio [OR], 0.731; 95% confidence interval [CI], 0.565-0.948; p = 0.018). There were no differences at 2 years between the MoM and MoP acetabular revisions in the incidence of dislocation, infection, or rerevision. When analyzed by patient sex and age group, there were more infections in the age 70 to 79 years MoP group compared with MoM (10 of 451 [5%] versus 29 of 628 [10%]; OR, 4.47; CI, 1.699-11.761; p = 0.001). There were high rates of dislocation, infection, and rerevision in both revision cohorts. The rate of dislocation was not greater after acetabular revision of MoM bearings at 2 years. Based on these findings, clinicians should counsel these patients preoperatively about the risks of these complications. Dual-mobility and constrained components have specific advantages and disadvantages in these settings and should be further studied. Level III, therapeutic study.

The Evolution of the Cup-Cage Technique for Major Acetabular Defects: Full and Half Cup-Cage Reconstruction.

PubMed

Sculco, Peter K; Ledford, Cameron K; Hanssen, Arlen D; Abdel, Matthew P; Lewallen, David G

2017-07-05

Complex acetabular reconstruction for major bone loss can require advanced methods such as the use of a cup-cage construct. The purpose of this study was to review outcomes after the initial development of the cup-cage technique and the subsequent evolution to the use of a half cup-cage construct. We performed a retrospective, single-center review of 57 patients treated with cup-cage reconstruction for major acetabular bone loss. All patients had major acetabular defects graded as Paprosky Type 2B through 3B, with 34 (60%) having an associated pelvic discontinuity. Thirty patients received a full cup-cage construct and 27, a half cup-cage construct. The mean follow-up was 5 years. Both the full and half cup-cage cohorts demonstrated significantly improved Harris hip score (HHS) values, from 36 to 72 at a minimum of 2 years of follow-up (p < 0.05). Early construct migration occurred in 4 patients, with stabilization prior to 2-year follow-up in all but 1 patient. Incomplete, zone-3, nonprogressive acetabular radiolucencies were observed in 2 (7%) of the full cup-cage constructs and 6 (22%) of the half cup-cage constructs. One patient with a full cup-cage construct underwent re-revision of the acetabular component for progressive migration and aseptic loosening. Short-term survivorship free from re-revision for any cause or reoperation was 89% (83% and 96% for full and half cup-cage cohorts, respectively). Both full and half cup-cage constructs demonstrated successful clinical outcomes and survivorship in the treatment of major acetabular defects and pelvic discontinuity. Each method is utilized on the basis of individual intraoperative findings, including the extent and pattern of bone loss, the quality and location of host bone remaining after preparation, and the presence of pelvic discontinuity. Longer-term follow-up is required to understand the durability of these constructs in treating major acetabular defects and pelvic discontinuity. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Evaluation of a new methodology to simulate damage and wear of polyethylene hip replacements subjected to edge loading in hip simulator testing.

PubMed

Partridge, Susan; Tipper, Joanne L; Al-Hajjar, Mazen; Isaac, Graham H; Fisher, John; Williams, Sophie

2018-05-01

Wear and fatigue of polyethylene acetabular cups have been reported to play a role in the failure of total hip replacements. Hip simulator testing under a wide range of clinically relevant loading conditions is important. Edge loading of hip replacements can occur following impingement under extreme activities and can also occur during normal gait, where there is an offset deficiency and/or joint laxity. This study evaluated a hip simulator method that assessed wear and damage in polyethylene acetabular liners that were subjected to edge loading. The liners tested to evaluate the method were a currently manufactured crosslinked polyethylene acetabular liner and an aged conventional polyethylene acetabular liner. The acetabular liners were tested for 5 million standard walking cycles and following this 5 million walking cycles with edge loading. Edge loading conditions represented a separation of the centers of rotation of the femoral head and the acetabular liner during the swing phase, leading to loading of the liner rim on heel strike. Rim damage and cracking was observed in the aged conventional polyethylene liner. Steady-state wear rates assessed gravimetrically were lower under edge loading compared to standard loading. This study supports previous clinical findings that edge loading may cause rim cracking in liners, where component positioning is suboptimal or where material degradation is present. The simulation method developed has the potential to be used in the future to test the effect of aging and different levels of severity of edge loading on a range of cross-linked polyethylene materials. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1456-1462, 2018. © 2017 Wiley Periodicals, Inc.

A hierarchy of computationally derived surgical and patient influences on metal on metal press-fit acetabular cup failure.

PubMed

Clarke, S G; Phillips, A T M; Bull, A M J; Cobb, J P

2012-06-01

The impact of anatomical variation and surgical error on excessive wear and loosening of the acetabular component of large diameter metal-on-metal hip arthroplasties was measured using a multi-factorial analysis through 112 different simulations. Each surgical scenario was subject to eight different daily loading activities using finite element analysis. Excessive wear appears to be predominantly dependent on cup orientation, with inclination error having a higher influence than version error, according to the study findings. Acetabular cup loosening, as inferred from initial implant stability, appears to depend predominantly on factors concerning the area of cup-bone contact, specifically the level of cup seating achieved and the individual patient's anatomy. The extent of press fit obtained at time of surgery did not appear to influence either mechanism of failure in this study. Copyright © 2012 Elsevier Ltd. All rights reserved.

The three-pin modified 'Harrington' procedure for advanced metastatic destruction of the acetabulum.

PubMed

Tillman, R M; Myers, G J C; Abudu, A T; Carter, S R; Grimer, R J

2008-01-01

Pathological fractures due to metastasis with destruction of the acetabulum and central dislocation of the hip present a difficult surgical challenge. We describe a series using a single technique in which a stable and long-lasting reconstruction was obtained using standard primary hip replacement implants augmented by strong, fully-threaded steel rods with cement and steel mesh, where required. Between 1997 and 2006, 19 patients with a mean age of 66 years (48 to 83) were treated using a modified Harrington technique. Acetabular destruction was graded as Harrington class II in six cases and class III in 13. Reconstruction was achieved using three 6.5 mm rods inserted through a separate incision in the iliac crest followed by augmentation with cement and a conventional cemented Charnley or Exeter primary hip replacement. There were no peri-operative deaths. At the final follow-up (mean 25 months (5 to 110)) one rod had fractured and one construct required revision. Of the 18 patients who did not require revision, 13 had died. The mean time to death was 16 months (5 to 55). The mean follow-up of the five survivors was 31 months (18 to 47). There were no cases of dislocation, deep infection or injury to a nerve, the blood vessels or the bladder.

Risk factors for unsuccessful acetabular press-fit fixation at primary total hip arthroplasty.

PubMed

Brulc, U; Antolič, V; Mavčič, B

2017-11-01

Surgeon at primary total hip arthroplasty sometimes cannot achieve sufficient cementless acetabular press-fit fixation and must resort to other fixation methods. Despite a predominant use of cementless cups, this issue is not fully clarified, therefore we performed a large retrospective study to: (1) identify risk factors related to patient or implant or surgeon for unsuccessful intraoperative press-fit; (2) check for correlation between surgeons' volume of operated cases and the press-fit success rate. Unsuccessful intra-operative press-fit more often occurs in older female patients, particular implants, due to learning curve and low-volume surgeons. Retrospective observational cohort of prospectively collected intraoperative data (2009-2016) included all primary total hip arthroplasty patients with implant brands that offered acetabular press-fit fixation only. Press-fit was considered successful if acetabulum was of the same implant brand as the femoral component without additional screws or cement. Logistic regression models for unsuccessful acetabular press-fit included patients' gender/age/operated side, implant, surgeon, approach (posterior n=1206, direct-lateral n=871) and surgery date (i.e. learning curve). In 2077 patients (mean 65.5 years, 1093 females, 1163 right hips), three different implant brands (973 ABG-II™-Stryker, 646 EcoFit™ Implantcast, 458 Procotyl™ L-Wright) were implanted by eight surgeons. Their unsuccessful press-fit fixation rates ranged from 3.5% to 23.7%. Older age (odds ratio 1.01 [95% CI: 0.99-1.02]), female gender (2.87 [95% CI: 2.11-3.91]), right side (1.44 [95% CI: 1.08-1.92]), surgery date (0.90 [95% CI: 1.08-1.92]) and particular implants were significant risk factors only in three surgeons with less successful surgical technique (higher rates of unsuccessful press-fit with Procotyl™-L and EcoFit™ [P=0.01]). Direct-lateral hip approach had a lower rate of unsuccessful press-fit than posterior hip approach (P<0.01), but there was no correlation between surgeons' volume and rate of successful press-fit (Spearman's rho=0.10, P=0.82). Subcohort of 961 patients with 5-7-years follow-up indicated higher early/late cup revision rates with unsuccessful press-fit. Success of press-fit fixation depends entirely on the surgeon and surgical approach. With proper operative technique, the unsuccessful press-fit fixation rate should be below 5% and the impact of patients' characteristics or implants on press-fit fixation is then insignificant. Findings of huge variability in operative technique between surgeons of the presented study emphasize the need for surgeon-specific data stratification in arthroplasty studies and indicate the possibility of false attribution of clinically observed phenomena to patient-related factors in pooled data of large centers or hip arthroplasty registers. Level III, retrospective observational case control study. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Monitoring the integrity of the cement-metal interface of total joint components in vitro using acoustic emission and ultrasound.

PubMed

Davies, J P; Tse, M K; Harris, W H

1996-08-01

Debonding of the cement-metal interface of cemented femoral components of total hip arthroplasty has been shown from clinical and autopsy material to be a common occurrence. Experimentally, debonding has been shown to increase markedly the strains in the adjacent cement mantle. Studies of autopsy-retrieved specimens demonstrate that debonding of the cement-metal interface is a key initiating event in loosening of cemented femoral components of total hip arthroplasty. However, both the radiographic and autopsy evidence of cement-metal interfacial debonding exist after the fact, that is, after debonding has occurred. The lack of prospective data showing that debonding does indeed occur under physiologic loading and occurs prior to other forms of failure of fixation leaves uncertain the issue of debonding and its role in initiating loosening of cemented femoral components. Knowing when, where, and to what extent the cement-metal interface debonds is critical information in understanding the process of loosening of cemented femoral components. Such information would contribute to improving the durability of stems and improving cementing techniques. In this study, the two nondestructive techniques of acoustic emission and ultrasonic evaluation of the cement-metal interface of cemented femoral stems of total hip arthroplasty were combined to investigate when, where, and to what extent cement-metal debonding occurred in vitro in simulated femurs loaded physiologically in fatigue in simulated single-leg stance. Debonding of the cement-metal interface of a cemented femoral component in this model was both an initiating event and a major mechanism of compromise of the cement-metal interface. Additional acoustic emission signals arose from cracks that developed in the cement.

Minimum ten-year results of primary bipolar hip arthroplasty for degenerative arthritis of the hip.

PubMed

Pellegrini, Vincent D; Heiges, Bradley A; Bixler, Brian; Lehman, Erik B; Davis, Charles M

2006-08-01

Bipolar hip arthroplasty has been advocated by some as an alternative to total hip arthroplasty for the treatment of degenerative arthritis of the hip. We sought to assess the results of this procedure at our institution after a minimum duration of follow-up of ten years. We retrospectively reviewed a consecutive series of 152 patients (173 hips) who underwent primary bipolar hemiarthroplasty for the treatment of symptomatic degenerative arthritis of the hip with a cementless femoral component between 1983 and 1987. Of the original cohort of 152 patients, ninety-two patients (104 hips) were available for clinical and radiographic review at a mean of 12.2 years postoperatively. At the time of the latest follow-up, self-administered Harris hip questionnaires were used to assess pain, mobility, activity level, and overall satisfaction with the procedure. Biplanar hip radiographs were made to evaluate bipolar shell migration, osteolysis, and femoral stem fixation. At the time of the latest follow-up, nineteen patients (nineteen hips) had undergone revision to total hip arthroplasty because of mechanical failure, and three patients (three hips) were awaiting revision because of symptomatic radiographic mechanical failure. Twelve acetabular revisions were performed or scheduled for the treatment of pelvic osteolysis or protrusio acetabuli secondary to component migration. Acetabular reconstruction required bone-grafting, an oversized shell, and/or a pelvic reconstruction ring. The overall rate of mechanical failure was 21.2% (twenty-two of 104 hips), with 91% (twenty) of the twenty-two failures involving the acetabular component. Reaming of the acetabulum at the time of the index arthroplasty was associated with a 6.4-fold greater risk of revision. The rate of implant survival, with revision because of mechanical failure as the end point, was 94.2% for femoral components and 80.8% for acetabular components at a mean of 12.2 years. Of the remaining sixty-nine patients (eighty-one hips) in whom the original prosthesis was retained, seventeen patients (24.6%) rated the pain as moderate to severe. Nearly 30% of patients with an intact prosthesis required analgesics on a regular basis. Radiographs were available for fifty-eight hips (including all of the hips with moderate to severe pain) after a minimum duration of follow-up of ten years; twenty-eight of these fifty-eight hips had radiographic evidence of acetabular component migration. This bipolar cup, when used for hemiarthroplasty in patients with symptomatic arthritis of the hip, was associated with unacceptably high rates of pain, migration, osteolysis, and the need for revision to total hip arthroplasty, especially when the acetabulum had been reamed. To the extent that these findings can be generalized to similar implant designs with conventional polyethylene, we do not recommend bipolar hemiarthroplasty as the primary operative treatment for degenerative arthritis of the hip.

A critical assessment of proximal macrotexturing on cemented femoral components.

PubMed

Duffy, G P; Muratoglu, O K; Biggs, S A; Larson, S L; Lozynsky, A J; Harris, W H

2001-12-01

We analyzed the cement-metal interface of 3 different types of femoral components that had proximal macrotexturing after in vitro insertion and after fatigue testing designed to produce debonding and micromotion. These components were compared with clinical retrieval specimens. The cement did not flow into the macrotexturing; rather, hollow, brittle volcanoes or calderas were formed. These fragile protrusions of cement become worn down or abraded by debonded components. This abrasion of cement may contribute to the early and aggressive osteolysis seen in some of these early failures with proximal macrotextured components. The formation of these volcanos and calderas can be aborted by placing bone-cement onto the macrotexturing before stem insertion. This simple technique allows the macrotexturing to be filled with cement.

Acetabular Morphology: Implications for Joint-preserving Surgery

PubMed Central

Ganz, Reinhold; Impellizzeri, Franco M.; Leunig, Michael

2009-01-01

Appropriate anatomic concepts for surgery to treat femoroacetabular impingement require a precise appreciation of the native acetabular anatomy. We therefore determined (1) the spatial acetabular rim profile, (2) the topography of the articular lunate surface, and (3) the 3-D relationships of the acetabular opening plane comparing 66 bony acetabula from 33 pelves in female and male pelves. The acetabular rim profile had a constant and regular wave-like outline without gender differences. Three prominences anterosuperiorly, anteroinferiorly and posteroinferiorly extended just above hemispheric level. Two depressions were below hemispheric level, of 9° at the anterior wall and of 21° along the posterosuperior wall. In 94% of all acetabula, the deepest extent of the articular surface was within 30° of the anterosuperior acetabular sector. In 99% of men and in 91% of women, the depth of the articular surface was at least 55° along almost half of the upper acetabular cup. The articular surface was smaller in women than in men. The acetabular opening plane was orientated in 21° ± 5° for version, 48° ± 4° for inclination and 19° ± 6° for acetabular tilt with no gender differences. We defined tilt as forward rotation of the entire acetabular cup around its central axis; because of interindividual variability of acetabular tilt, descriptions of acetabular lesions during surgery, CT scanning and MRI should be defined and recorded in relation to the acetabular notch. Acetabular tilt and pelvic tilt should be separately identified. We believe this information important for surgeons performing rim trimming in FAI surgery or performing acetabular osteotomies. PMID:19130159

Primary total hip arthroplasty in Catalonia: What is the clinical evidence that supports our prosthesis?

PubMed

Chaverri-Fierro, D; Lobo-Escolar, L; Espallargues, M; Martínez-Cruz, O; Domingo, L; Pons-Cabrafiga, M

The implementation of National Prostheses Registries allows us to obtain a large amount of data and make conclusions in order to improve the use of them. Sweden was the first country to implement a National Prostheses Registry in 1979. Catalonia has been doing this since 2005. The aim of our study is to analyse the evidence that supports primary total hip replacement in Catalonia in the last 9 years, based on the Arthroplasty Registry of Catalonia (RACat). A review of the literature was carried out of the prosthesis (acetabular cups/stems) reported in the RACat between the period 2005 to 2013 in the following databases: ODEP (Orthopaedic Data Evaluation Panel), TRIP database, PubMed, and Google Scholar. Those prostheses implanted in less than 10 units (182 acetabular components corresponding to 49 models/228 stems corresponding to 63 models) were excluded. A total of 18,634 (99%) implanted acetabular cups were analysed out of a total number of 18,816, corresponding to 74 different models. In 18 models (2527 acetabular cups) no clinical evidence to support its use was found. An analysis was performed on 19,367 (98.84%) out of a total number of 19,595 implanted stems, corresponding to 75 different models. In 16 models (1845 stems) no clinical evidence was found to support their use. Variable evidence was found in the 56 models of acetabular cups (16,107) and 59 models of stems (17,522), most of it corresponding to level iv clinical evidence. There was a significant number implanted prostheses evaluated (13.56% acetabular cups/9.5% stems) for which no clinical evidence was found. The elevated number of models is highlighted (49 types for acetabular cups/63 types for stems) with less than 10 units implanted, which corresponds to only 1% of the total implants. The use of arthroplasty registers is shown to be an extremely helpful tool that allows analyses and conclusions to be made for the follow-up and post-marketing surveillance period. Copyright © 2016 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Post-deformation shape-recovery behavior of vitamin E-diffused, radiation crosslinked polyethylene acetabular components.

PubMed

Takahashi, Yasuhito; Tateiwa, Toshiyuki; Shishido, Takaaki; Masaoka, Toshinori; Kubo, Kosuke; Yamamoto, Kengo

2016-10-01

The in-vivo progression of creep and wear in ultra-high molecular weight polyethylene (UHMWPE) acetabular liners has been clinically evaluated by measuring radiographic penetration of femoral heads. In such clinical assessments, however, viscoelastic strain relaxation has been rarely considered after a removal of hip joint loading, potentially leading to an underestimation of the penetrated thickness. The objective of this study was to investigate shape-recovery behavior of pre-compressed, radiation crosslinked and antioxidant vitamin E-diffused UHMWPE acetabular liners, and also to characterize the effects of varying their internal diameter (ID) and wall thickness (WT). We applied uniaxial compression to the UHMWPE specimens of various ID (28, 32, 36mm) and WT (4.8, 6.8, 8.9mm) for 4320min under the constant load of 3000N, and subsequently monitored the strain-relaxation behavior as a function of time after unloading. It was observed that there was a considerable shape recovery of the components after removal of the external static load. Reducing ID and WT significantly accelerated the rate of creep strain recovery, and varying WT was more sensitive to the recovery behavior than ID. Creep deformation of the tested liners recovered mostly within the first 300min after unloading. Note that approximately half of the total recovery amount proceeded just within 5min after unloading. These results suggest a remarkably high capability of shape recovery of vitamin E-diffused highly crosslinked UHMWPE. In conclusion, the time-dependent shape recovering and the diameter-thickness effect on its behavior should be carefully considered when the postoperative penetration is quantified in highly crosslinked UHMWPE acetabular liners (especially on the non-weight bearing radiographs). Copyright © 2016 Elsevier Ltd. All rights reserved.

Early experience with dual mobility acetabular systems featuring highly cross-linked polyethylene liners for primary hip arthroplasty in patients under fifty five years of age: an international multi-centre preliminary study.

PubMed

Epinette, Jean-Alain; Harwin, Steven F; Rowan, Fiachra E; Tracol, Philippe; Mont, Michael A; Chughtai, Morad; Westrich, Geoffrey H

2017-03-01

To evaluate early performance of contemporary dual mobility acetabular systems with second generation annealed highly cross-linked polyethylene for primary hip arthroplasty of patients under 55 years of age. A prospective observational five years study across five centers in Europe and the USA of 321 patients with a mean age of 48.1 years was performed. Patients were assessed for causes of revision, hip instability, intra-prosthetic dissociation, Harris hip score and radiological signs of osteolysis. There were no dislocations and no intra-prosthetic dissociations. Kaplan Meier analysis demonstrated 97.51% survivorship for all cause revision and 99.68% survivorship for acetabular component revision at five years. Mean Harris hip score was 93.6. Two acetabular shells were revised for neck-rim implant impingement without dislocation and ten femoral stems were revised for causes unrelated to dual mobility implants. Contemporary highly cross-linked polyethylene dual mobility systems demonstrate excellent early clinical, radiological, and survivorship results in a cohort of patients that demand high performance from their implants. It is envisaged that DM and second generation annealed HXLPE may reduce THA instability and wear, the two most common causes of THA revision in hip arthroplasty.

Retrieval analysis of ceramic-coated metal-on-polyethylene total hip replacements.

PubMed

Khatkar, Harman; Hothi, Harry; de Villiers, Danielle; Lausmann, Christian; Kendoff, Daniel; Gehrke, Thorsten; Skinner, John; Hart, Alister

2017-06-01

Ceramic coatings have been used in metal-on-polyethylene (MOP) hips to reduce the risk of wear and also infection; the clinical efficacy of this remains unclear. This retrieval study sought to better understand the performance of coated bearing surfaces. Forty-three coated MOP components were analysed post-retrieval for evidence of coating loss and gross polyethylene wear. Coating loss was graded using a visual semi-quantitative protocol. Evidence of gross polyethylene wear was determined by radiographic analysis and visual inspection of the retrieved implants. All components with gross polyethylene wear (n = 10) were revised due to a malfunctioning acetabular component; 35 % (n = 15) of implants exhibited visible coating loss and the incidence of polyethylene wear in samples with coating loss was 54 %, significantly (p = 0.02) elevated compared to samples with intact coatings (14 %). In this study we found evidence of coating loss on metal femoral heads which was associated with increased wear of the corresponding polyethylene acetabular cups.

Over 25 years survival after Charnley's total hip arthroplasty.

PubMed

Caton, Jacques; Prudhon, Jean Louis

2011-02-01

Since 1962, the low friction arthroplasty (LFA) developed by Sir John Charnley has spread widely throughout the world. Many series have reported long-term results. Polyethylene (PE) wear is well known. The average wear ratio is about 0.1 mm a year. Many factors may influence that wear process. The authors describe two different series of patients operated upon with Charnley's total hip arthroplasty (THA) using the original cemented stem and a non modular 22.2-mm head, with a cemented full polyethylene acetabular socket. Outcomes confirm excellent patient function after 25 years. They emphasise the fact that PE is the weak point of total hip arthroplasty. Function may be excellent even though PE wear is significant. In several cases, no wear at the maximum follow-up was detectable. This study confirms different publications relating long-term follow-up with LFA. During a Charnley meeting in Lyon, we published a survival curve of 85% after 25 years. Berry et al. published a 86.5% survival curve (J Bone Joint Surg Am 84:171-177, 2002). In 1995, Luc and Marcel Kerboul published a 77% survival rate after 20 years in young patients under 40 years old at the time of the surgery. In 2009, Callaghan et al. published a series of 35 years follow-up with a ratio of 78% survivorship (J Bone Joint Surg Br 91:2617-2621). Could the long-term results be improved? Through recent decades, many solutions have been introduced to improve the survivorship of THA including bearing surfaces such as alumina-on-alumina and metal-on-metal. Different problems have occurred with these solutions. LFA might be improved by working on the nature and the quality of the head. Improvements might also be obtained by working on the quality and the hardness of the acetabular socket.

Overdiagnosing of femoroacetabular impingement: correlation between clinical presentation and computed tomography in symptomatic patients☆

PubMed Central

Canella, Richard Prazeres; Adam, Guilherme Pradi; de Castillo, Roberto André Ulhôa; Codonho, Daniel; Ganev, Gerson Gandhi; de Vicenzi, Luiz Fernando

2016-01-01

Objective To correlate the angles between the acetabulum and the proximal femur in symptomatic patients with femoroacetabular impingement (FAI), using computed tomography (CT). Methods We retrospectively evaluated 103 hips from 103 patients, using multislice CT to measure the acetabular age, acetabular version (in its supraequatorial portion and in its middle third), femoral neck version, cervical-diaphyseal and alpha angles and the acetabular depth. For the statistical analysis, we used the Pearson correlation coefficient. Results There were inverse correlations between the following angles: (1) acetabular coverage versus alpha angle (p = 0.019); (2) acetabular version (supraequatorial) versus alpha angle (p = 0.049). For patients with femoral anteversion lower than 15 degrees: (1) acetabular version (supraequatorial) versus alpha angle (p = 0.026); (2) acetabular version (middle third) versus alpha angle (p = 0.02). For patients with acetabular version (supraequatorial) lower than 10 degrees: (1) acetabular version (supraequatorial) versus alpha angle (p = 0.004); (2) acetabular version (middle third) versus alpha angle (p = 0.009). Conclusion There was a statistically significant inverse correlation between the acetabular version and alpha angles (the smaller the acetabular anteversion angle was, the larger the alpha angle was) in symptomatic patients, thus supporting the hypothesis that FAI occurs when cam and pincer findings due to acetabular retroversion are seen simultaneously, and that the latter alone does not cause FAI, which leads to overdiagnosis in these cases. PMID:27069890

Overdiagnosing of femoroacetabular impingement: correlation between clinical presentation and computed tomography in symptomatic patients.

PubMed

Canella, Richard Prazeres; Adam, Guilherme Pradi; de Castillo, Roberto André Ulhôa; Codonho, Daniel; Ganev, Gerson Gandhi; de Vicenzi, Luiz Fernando

2016-01-01

To correlate the angles between the acetabulum and the proximal femur in symptomatic patients with femoroacetabular impingement (FAI), using computed tomography (CT). We retrospectively evaluated 103 hips from 103 patients, using multislice CT to measure the acetabular age, acetabular version (in its supraequatorial portion and in its middle third), femoral neck version, cervical-diaphyseal and alpha angles and the acetabular depth. For the statistical analysis, we used the Pearson correlation coefficient. There were inverse correlations between the following angles: (1) acetabular coverage versus alpha angle (p = 0.019); (2) acetabular version (supraequatorial) versus alpha angle (p = 0.049). For patients with femoral anteversion lower than 15 degrees: (1) acetabular version (supraequatorial) versus alpha angle (p = 0.026); (2) acetabular version (middle third) versus alpha angle (p = 0.02). For patients with acetabular version (supraequatorial) lower than 10 degrees: (1) acetabular version (supraequatorial) versus alpha angle (p = 0.004); (2) acetabular version (middle third) versus alpha angle (p = 0.009). There was a statistically significant inverse correlation between the acetabular version and alpha angles (the smaller the acetabular anteversion angle was, the larger the alpha angle was) in symptomatic patients, thus supporting the hypothesis that FAI occurs when cam and pincer findings due to acetabular retroversion are seen simultaneously, and that the latter alone does not cause FAI, which leads to overdiagnosis in these cases.

Porous titanium particles for acetabular reconstruction in total hip replacement show extensive bony armoring after 15 weeks

PubMed Central

Walschot, Lucas H B; Aquarius, René; Verdonschot, Nico; Buma, Pieter

2014-01-01

Background and purpose — The bone impaction grafting technique restores bone defects in total hip replacement. Porous titanium particles (TiPs) are deformable, like bone particles, and offer better primary stability. We addressed the following questions in this animal study: are impacted TiPs osteoconductive under loaded conditions; do released micro-particles accelerate wear; and are systemic titanium blood levels elevated after implantation of TiPs? Animals and methods — An AAOS type-III defect was created in the right acetabulum of 10 goats weighing 63 (SD 6) kg, and reconstructed with calcium phosphate-coated TiPs and a cemented polyethylene cup. A stem with a cobalt chrome head was cemented in the femur. The goats were killed after 15 weeks. Blood samples were taken pre- and postoperatively. Results — The TiP-graft layer measured 5.6 (SD 0.8) mm with a mean bone ingrowth distance of 2.8 (SD 0.8) mm. Cement penetrated 0.9 (0.3–1.9) mm into the TiPs. 1 reconstruction showed minimal cement penetration (0.3 mm) and failed at the cement-TiP interface. There were no signs of accelerated wear, metallic particle debris, or osteolysis. Median systemic titanium concentrations increased on a log-linear scale from 0.5 (0.3–1.1) parts per billion (ppb) to 0.9 (0.5–2.8) ppb (p = 0.01). Interpretation — Adequate cement pressurization is advocated for impaction grafting with TiPs. After implantation, calcium phosphate-coated TiPs were osteoconductive under loaded conditions and caused an increase in systemic titanium concentrations. However, absolute levels remained low. There were no signs of accelerated wear. A clinical pilot study should be performed to prove that application in humans is safe in the long term. PMID:25238431

Fixation method does not affect restoration of rotation center in hip replacements: A single-site retrospective study

PubMed Central

2012-01-01

Background Aseptic loosening is one of the greatest problems in hip replacement surgery. The rotation center of the hip is believed to influence the longevity of fixation. The aim of this study was to compare the influence of cemented and cementless cup fixation techniques on the position of the center of rotation because cemented cup fixation requires the removal of more bone for solid fixation than the cementless technique. Methods We retrospectively compared pre- and post-operative positions of the hip rotation center in 25 and 68 patients who underwent artificial hip replacements in our department in 2007 using cemented or cementless cup fixation, respectively, with digital radiographic image analysis. Results The mean horizontal and vertical distances between the rotation center and the acetabular teardrop were compared in radiographic images taken pre- and post-operatively. The mean horizontal difference was −2.63 mm (range: -11.00 mm to 10.46 mm, standard deviation 4.23 mm) for patients who underwent cementless fixation, and −2.84 mm (range: -10.87 to 5.30 mm, standard deviation 4.59 mm) for patients who underwent cemented fixation. The mean vertical difference was 0.60 mm (range: -20.15 mm to 10.00 mm, standard deviation 3.93 mm) and 0.41 mm (range: -9.26 mm to 6.54 mm, standard deviation 3.58 mm) for the cementless and cemented fixation groups, respectively. The two fixation techniques had no significant difference on the position of the hip rotation center in the 93 patients in this study. Conclusions The hip rotation center was similarly restored using either the cemented or cementless fixation techniques in this patient cohort, indicating that the fixation technique itself does not interfere with the position of the center of rotation. To completely answer this question further studies with more patients are needed. PMID:22686355

Biomechanical comparison of the strength of adhesion of polymethylmethacrylate cement to zirconia ceramic and cobalt-chromium alloy components in a total knee arthroplasty.

PubMed

Kumahashi, Nobuyuki; Uchio, Yuji; Kitamura, Nobuto; Satake, Shigeru; Iwamoto, Mikio; Yasuda, Kazunori

2014-11-01

The purpose of this study was to clarify the biomechanical characteristics of cement-material interfaces for the zirconia ceramic and cobalt-chromium (Co-Cr) alloy femoral components used for total knee arthroplasty. In the first sub-study, we compared the strength of adhesion of the cement to flat plates, by tensile testing under dry and moistened conditions. In the second sub-study, we compared the maximum load of the cement-component complex by tensile testing. In the third sub-study, we compared the fatigue characteristics of the cement-component complex by use of a dynamic tensile testing machine. Under dry conditions, the maximum strength of adhesion to the zirconia ceramic plate was the same as that to the Co-Cr alloy plate. Under moistened conditions, however, the strength of adhesion to the zirconia ceramic plate was significantly lower (p = 0.0017) whereas the strength of adhesion to the Co-Cr alloy plate was not reduced. Maximum load for the cement-component complexes for zirconia ceramic and Co-Cr alloy was no different under both dry and moistened conditions. Fatigue testing showed that cement-zirconia adhesion was stronger than cement-Co-Cr alloy adhesion (p = 0.0161). The strength of adhesion of cement to zirconia ceramic is substantially weaker under wet conditions than under dry conditions. The mechanical properties of cement-zirconia ceramic component complexes and cement-Co-Cr alloy component complexes are equivalent.

Adhesive strength of total knee endoprostheses to bone cement - analysis of metallic and ceramic femoral components under worst-case conditions.

PubMed

Bergschmidt, Philipp; Dammer, Rebecca; Zietz, Carmen; Finze, Susanne; Mittelmeier, Wolfram; Bader, Rainer

2016-06-01

Evaluation of the adhesive strength of femoral components to the bone cement is a relevant parameter for predicting implant safety. In the present experimental study, three types of cemented femoral components (metallic, ceramic and silica/silane-layered ceramic) of the bicondylar Multigen Plus knee system, implanted on composite femora were analysed. A pull-off test with the femoral components was performed after different load and several cementing conditions (four groups and n=3 components of each metallic, ceramic and silica/silane-layered ceramic in each group). Pull-off forces were comparable for the metallic and the silica/silane-layered ceramic femoral components (mean 4769 N and 4298 N) under standard test condition, whereas uncoated ceramic femoral components showed reduced pull-off forces (mean 2322 N). Loading under worst-case conditions led to decreased adhesive strength by loosening of the interface implant and bone cement using uncoated metallic and ceramic femoral components, respectively. Silica/silane-coated ceramic components were stably fixed even under worst-case conditions. Loading under high flexion angles can induce interfacial tensile stress, which could promote early implant loosening. In conclusion, a silica/silane-coating layer on the femoral component increased their adhesive strength to bone cement. Thicker cement mantles (>2 mm) reduce adhesive strength of the femoral component and can increase the risk of cement break-off.

[Prophylactic osteotomy of pelvis in dysplastic acetabulum.].

PubMed

Richtr, M; Sosna, A

1998-01-01

Acetabular dysplasia and anatomical changes of pelvis accompanied with gracility of iliac bone pose a problem for a reliable fixation of acetabular component. In extreme cases the bone stock is not sufficient to accommodate the smallest size of the cup. Sometimes even reaming of the bed down to lamina interna is not sufficient for an adequate covering of the implant. Consequently, weakening of the bottom of acetabulum may be not only one of the causes of the failure of the implant but it makes difficult also the following revision surgeries. Therefore in acetabular dysplasia the authors recommend acetabuloplasty of the bottom of acetabulum preserving its original thickness including inner cortex. They recommend to perform osteotomy of the full thickness of the medial wall of acetabulum and move the massive bone graft created in this way farther into pelvis. At the same time they take care to preserve blood supply of the bone graft by retaining corticoperiostal bridge by means of osteoclasia. The suggested procedure allows full coverage of the implant by iliac bone and at the same time preserves a firm support of acetabular fossa. The original thickness of the medial wall of acetabulum is considered by authors as a significant antimigration barrier. In the period 1991 -1994 the authors used this method at Ist Orthopaedic Clinic of 1st Medical Faculty, Charles University in Prague in total in 16 patients. In all of them after 6 months the bone graft was fully absorbed. Remodelling of the bone graft occurred 1 to 2 years after the surgery and after that the thickness of the graft remained the same. Neither any change of the structure nor reduction of the thickness of the graft was found between 3rd and 4th year after the surgery. The nature of trabecular remodelling of the bone graft corresponds to the transfer of forces in loading the graft by acetabular cup. Key words: acetabuloplasty, osteotomy of the medial wall of acetabulum, osteotomy of pelvis, THR, acetabular dysplasia.

The design and development of a triaxial wear-testing joint simulator.

PubMed

Green, A S; O'Connell, M K; Lyons, A S; James, S P

1999-01-01

Most of the existing wear testers created to wear test total hip replacements, specifically the acetabular component, are designed to exert only an axial force and provide rotation in a close approximation of the actual femoral movement. The Rocky Mountain Joint Simulator was designed to exert three orthogonal forces and provide rotations about the X-, Y- and Z-axes to more closely simulate the physiological forces and motions found in the human gait cycle. The RMJS was also designed with adaptability for other joints, such as knees or canine hips, through the use of hydraulics and a computer-programmable control system. Such adaptability and functionality allows the researcher to more closely model a gait cycle, thereby obtaining wear patterns that resemble those found in retrieved implants more closely than existing simulators. Research is ongoing into the tuning and evaluation of the machine and preliminary acetabular component wear test results will be presented at the conference.

Acetabular-epiphyseal angle and hip dislocation in cerebral palsy: a preliminary study.

PubMed

Alí-Morell, O J; Zurita-Ortega, F; Davó-Jiménez, I; Segura-Biedma, S

To relate, in non-ambulatory subjects with palsy, Reimers' migration percentage with standardized radiological measurements, including the acetabular-epiphyseal angle. Descriptive, observational and transversal study of 15 individuals with cerebral palsy at levels IV and V of the Gross Motor Function Classification System, aged between 3 and 9 years. Radiological measurements of the acetabular index, Hilgenreiner's epiphyseal angle, acetabular-epiphyseal angle, neck-shaft angle and Reimers' migration percentage of each of the hips were performed. Correlations between acetabular index, epiphyseal angle and acetabular-epiphyseal angle were obtained with respect to the Reimers migration percentage. For hips with a migration rate of 15% or less, a positive correlation was observed between acetabular and epiphyseal angles. In our population, the measurement between acetabular and epiphyseal inclination represents the highest association with the hip migration percentage. Copyright © 2018 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Fretting and Corrosion at the Backside of Modular Cobalt Chromium Acetabular Inserts: A Retrieval Analysis.

PubMed

Tarity, T David; Koch, Chelsea N; Burket, Jayme C; Wright, Timothy M; Westrich, Geoffrey H

2017-03-01

Adverse local tissue reaction formation has been suggested to occur with the Modular Dual Mobility (MDM) acetabular design. Few reports in the literature have evaluated fretting and corrosion damage between the acetabular shell and modular metal inserts in this modular system. We evaluated a series of 18 retrieved cobalt chromium MDM inserts for evidence of fretting and corrosion. We assessed the backsides of 18 MDM components for evidence of fretting and corrosion in polar and taper regions based on previously established methods. We collected and assessed 30 similarly designed modular inserts retrieved from metal-on-metal (MoM) total hip arthroplasties as a control. No specific pattern of fretting or corrosion was identified on the MDM inserts. Both fretting and corrosion were significantly greater in the MoM cohort than the MDM cohort, driven by higher fretting and corrosion scores in the engaged taper region of the MoM inserts. MoM components demonstrated more fretting and corrosion than MDM designs, specifically at the taper region, likely driven by differences in the taper engagement mechanism and geometry among the insert designs. The lack of significant fretting and corrosion observed in the MDM inserts are inconsistent with recent claims that this interface may produce clinically significant metallosis and adverse local tissue reactions. Copyright © 2016 Elsevier Inc. All rights reserved.

Intra-operative digital imaging: assuring the alignment of components when undertaking total hip arthroplasty.

PubMed

Hambright, D; Hellman, M; Barrack, R

2018-01-01

The aims of this study were to examine the rate at which the positioning of the acetabular component, leg length discrepancy and femoral offset are outside an acceptable range in total hip arthroplasties (THAs) which either do or do not involve the use of intra-operative digital imaging. A retrospective case-control study was undertaken with 50 patients before and 50 patients after the integration of an intra-operative digital imaging system in THA. The demographics of the two groups were comparable for body mass index, age, laterality and the indication for surgery. The digital imaging group had more men than the group without. Surgical data and radiographic parameters, including the inclination and anteversion of the acetabular component, leg length discrepancy, and the difference in femoral offset compared with the contralateral hip were collected and compared, as well as the incidence of altering the position of a component based on the intra-operative image. Digital imaging took a mean of five minutes (2.3 to 14.6) to perform. Intra-operative changes with the use of digital imaging were made for 43 patients (86%), most commonly to adjust leg length and femoral offset. There was a decrease in the incidence of outliers when using intra-operative imaging compared with not using it in regard to leg length discrepancy (20% versus 52%, p = 0.001) and femoral offset inequality (18% versus 44%, p = 0.004). There was also a difference in the incidence of outliers in acetabular inclination (0% versus 7%, p = 0.023) and version (0% versus 4%, p = 0.114) compared with historical results of a high-volume surgeon at the same centre. The use of intra-operative digital imaging in THA improves the accuracy of the positioning of the components at THA without adding a substantial amount of time to the operation. Cite this article: Bone Joint J 2018;100B(1 Supple A):36-43. ©2018 The British Editorial Society of Bone & Joint Surgery.

Evaluation of the three-dimensional bony coverage before and after rotational acetabular osteotomy.

PubMed

Tanaka, Takeyuki; Moro, Toru; Takatori, Yoshio; Oshima, Hirofumi; Ito, Hideya; Sugita, Naohiko; Mitsuishi, Mamoru; Tanaka, Sakae

2018-02-26

Rotational acetabular osteotomy is a type of pelvic osteotomy that involves rotation of the acetabular bone to improve the bony coverage of the femoral head for patients with acetabular dysplasia. Favourable post-operative long-term outcomes have been reported in previous studies. However, there is a paucity of published data regarding three-dimensional bony coverage. The present study investigated the three-dimensional bony coverage of the acetabulum covering the femoral head in hips before and after rotational acetabular osteotomy and in normal hips. The computed tomography data of 40 hip joints (12 joints before and after rotational acetabular osteotomy; 16 normal joints) were analyzed. The three-dimensional bony coverage of each joint was evaluated using original software. The post-operative bony coverage improved significantly compared with pre-operative values. In particular, the anterolateral aspect of the acetabulum tended to be dysplastic in patients with acetabular dysplasia compared to those with normal hip joints. However, greater bony coverage at the anterolateral aspect was obtained after rotational acetabular osteotomy. Meanwhile, the results of the present study may indicate that the bony coverage in the anterior aspect may be excessive. Three-dimensional analysis indicated that rotational acetabular osteotomy achieved favorable bony coverage. Further investigations are necessary to determine the ideal bony coverage after rotational acetabular osteotomy.

Reconstruction of the pelvic brim and its role in the reduction accuracy of displaced T-shaped acetabular fracture.

PubMed

Harnroongroj, T; Asavamongkolkul, A; Chareancholvanich, K

2000-05-01

Open reduction of the displaced T-shaped acetabular fracture has a problem of accuracy of the fracture reduction. This study was carried out to demonstrate that the reconstruction of the pelvic brim by approaching the pubo-acetabular fragment plays a role in the accuracy of the reduction of displaced T-shaped acetabular fractures. From 1975 to 1990, a retrospective study was carried out of 22 patients who sustained a displaced T-shaped acetabular fracture. The patients were operated on by open reduction and internal fixation of the ischio-acetabular fragment to the posterior column without restoration of the pelvic brim. Radiographs of the pelvis were reviewed. The result showed that there was displacement of the pubo-acetabular fragment including the medial wall in all cases. As the result of this study, a prospective study between 1990 and 1997 was carried out of 15 patients who sustained displaced T-shaped acetabular fractures including 3 cases with medial displacement of the femoral head. The pubo-acetabular fragment was anatomically reduced and fixed to the anterior column of the acetabulumn as the first approach to restore a disrupted pelvic brim. There, patterns of the acetabular fracture were subsequently re-evaluated especially the ischio-acetabular fragment including the position of the femoral head by using an intraoperative portable X-ray technique. The stability of the hip joint was assessed by hip flexion. The intraoperative radiograph appearances of the ischio-acetabular fragment were visually confirmed by a second surgical exposure. The results showed that the intraoperative radiographs gave spontaneous reduction of the ischio-acetabular fragment in all patients except one. There was a reduction of the displaced femoral head into the hip socket in the three patients. The hip joints were stable in all patients. The second surgical exposure showed that there was good spontaneous reduction of the ischio-acetabular fragment to the posterior column by ligamentotaxis in 14 patients. Therefore, it is not necessary to address the ischio-acetabular fragment. In the exceptional case, the ischio-acetabular fragment was displaced as a free bone which could not be reduced by ligamentotaxis. However, reduction and internal fixation of the ischio-acetabular fragment to the posterior column for complete re-application of the hip joint onto the pelvic ring of this case was facilitated. Postoperative 2 year and 5 year follow-up showed that the fracture had healed without heterotrophic ossification or premature osteoarthrosis of the hip joint. The exceptional case had a broken plate at the anterior column of the acetabulum. Hip function was evaluated clinically using Merle D' Aubigne's hip score. All patients had a "very good score". The study showed that reconstruction of the pelvic brim by anatomical reduction and fixation of the pubo-acetabular fragment to the anterior column plays an important role in the accuracy of fracture reduction of a displaced T-shaped acetabular fracture.

Estimated survival probability of the Spotorno total hip arthroplasty after a 15- to 21-year follow-up: one surgeon's results.

PubMed

Terré, Ricardo A

2010-01-01

We retrospectively assess 171 consecutive total hip arthroplasties (THAs) with a Spotorno CLS uncemented prosthesis implanted through a Hardinge approach. The mean follow-up was 17.9 years. All consecutive operations were performed by 1 surgeon. Eight patients had been lost to follow-up, and 77 had died for unrelated causes. Overall, 4 stems and 19 cups underwent revision. The cumulative survival rate at 21 years was 79.02% (95% confidence interval [95% CI], 45.98-100.00%) for the acetabular component and 96.71% (95% CI, 60.71-100.00%) for the stem. We can conclude that failure of the Spotorno CLS THA is mainly due to its acetabular component (relative risk 4.5). Survival results for the Spotorno CLS stem exceed the patients? life expectancies in the 60- to 70-year-old population in our area. Loosening with or without fatigue fracture of the component and the learning curve for proper implantation have been the main causes for the expansion cup failure.

40 CFR 63.6015 - What definitions apply to this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... cements, bead cements, tire building cements and solvents, green tire spray, blemish repair paints, side... in tire component identification; component storage; tire building; tire curing; and tire repair... of warm-up mills, extruders, calendars, tire building, or other tire component and tire manufacturing...

Preliminary application of computer-assisted patient-specific acetabular navigational template for total hip arthroplasty in adult single development dysplasia of the hip.

PubMed

Zhang, Yuan Z; Chen, Bin; Lu, Sheng; Yang, Yong; Zhao, Jian M; Liu, Rui; Li, Yan B; Pei, Guo X

2011-12-01

The considerable variation in anatomical abnormalities of hip joints associated with different types of developmental dysplasia of hip (DDH) makes reconstruction in total hip arthroplasty (THA) difficult. It is desirable to create patient-specific designs for THA procedures. In the cases of adult single DDH, an accuracy-improved method has been developed for acetabular cup prosthesis implantation of hip arthroplasty. From October 2007 to November 2008, 22 patients with single DDH (according to the Crowe standard, all dysplasia hips were classified as type I) were scanned with spiral CT pre-operatively. These patients scheduled for THA were randomly assigned to undergo either conventional THA (control group, n = 11) or navigation template implantation (NT group, n = 11). In the NT group, three-dimensional (3D) CT pelvis image data were transferred to a computer workstation and 3D models of the hip were reconstructed using the Mimics software. The 3D models were then processed by the Imageware software. In brief, a template that best fitted the location and shape of the acetabular cup was 'reversely' built from the 3D model, the rotation centre of the pathological hip determined by mirroring that of the healthy site, and a guiding hole in the template was then designed. The navigational templates were manufactured using a rapid prototyping machine. These navigation templates guide acetabular component placement. Based on the predetermined abduction angle 45° and anteversion angle 18°, after 1 year follow-up, the NT group showed significantly smaller differences (1.6° ± 0.4°, 1.9° ± 1.1°) from the predetermined angles than those in the control group (5.8° ± 2.9°, 3.9° ± 2.5°) (P < 0.05). The template designs facilitated accurate placement of acetabular components in dysplasia of acetabulum. The hip's center of rotation in DDH could be established using computer-aided design, which provides a useful method for the accurate location of prosthesis with a low cost-performance ratio without excessive technical workload on the surgical team. Copyright © 2011 John Wiley & Sons, Ltd.

Midterm Outcomes of Revision Total Hip Arthroplasty With the Use of a Multihole Highly-Porous Titanium Shell.

PubMed

Delanois, Ronald E; Gwam, Chukwuweike U; Mohamed, Nequesha; Khlopas, Anton; Chughtai, Morad; Malkani, Arthur L; Mont, Michael A

2017-09-01

We are reporting on the minimum 5-year outcomes of patients who underwent revision total hip arthroplasty (THA) using a specific highly-porous titanium shell. We assessed (1) aseptic and all-cause survivorship; (2) functional outcomes; (3) complications; and (4) radiographic outcomes. Two hospital databases were evaluated for patients who underwent revision THA due to component instability or aseptic loosening using a cementless highly-porous titanium shell between September 2006 and December 2011. This yielded 35 patients who had a mean age of 61 years (range 14-88 years). Patients had a mean follow-up of 6 years (minimum 5 years). All-cause and aseptic survivorship of the shell was calculated. Functional outcomes were assessed using the Harris Hip Score. We determined the incidence of postoperative complications and performed radiographic evaluation of pelvic radiographs from regular office visits. The aseptic survivorship of the acetabular component was 97% (95% confidence interval; 8.1-9.5). The all-cause survivorship of the acetabular component was 91% (95% confidence interval; 7.3-8.1). One patient had an aseptic failure and 2 patients had septic failures. The mean postoperative Harris Hip Score was 76 points (range, 61-91 points). Excluding the aseptic and septic failures, there was no osteolysis or progressive radiolucencies present on radiographic evaluation at final follow-up. At a minimum of 5-year follow-up, the highly-porous titanium acetabular revision shell has excellent survivorship and functional outcomes. Although long-term follow-up is needed to further monitor these implants, the results are promising and demonstrate that this prosthesis may be an excellent option for patients undergoing revision THA. Copyright © 2017 Elsevier Inc. All rights reserved.

Three-dimensional finite analysis of acetabular contact pressure and contact area during normal walking.

PubMed

Wang, Guangye; Huang, Wenjun; Song, Qi; Liang, Jinfeng

2017-11-01

This study aims to analyze the contact areas and pressure distributions between the femoral head and mortar during normal walking using a three-dimensional finite element model (3D-FEM). Computed tomography (CT) scanning technology and a computer image processing system were used to establish the 3D-FEM. The acetabular mortar model was used to simulate the pressures during 32 consecutive normal walking phases and the contact areas at different phases were calculated. The distribution of the pressure peak values during the 32 consecutive normal walking phases was bimodal, which reached the peak (4.2 Mpa) at the initial phase where the contact area was significantly higher than that at the stepping phase. The sites that always kept contact were concentrated on the acetabular top and leaned inwards, while the anterior and posterior acetabular horns had no pressure concentration. The pressure distributions of acetabular cartilage at different phases were significantly different, the zone of increased pressure at the support phase distributed at the acetabular top area, while that at the stepping phase distributed in the inside of acetabular cartilage. The zones of increased contact pressure and the distributions of acetabular contact areas had important significance towards clinical researches, and could indicate the inductive factors of acetabular osteoarthritis. Copyright © 2016. Published by Elsevier Taiwan.

Biomechanical Evaluation of All-Polyethylene Pegged Bony Ingrowth Glenoid Fixation Techniques on Implant Micromotion.

PubMed

Wiater, Brett P; Moravek, James E; Kurdziel, Michael D; Baker, Kevin C; Wiater, J Michael

2016-01-01

Newer glenoid components that allow for hybrid cement fixation via traditional cementation of peripheral pegs and bony ingrowth into an interference-fit central peg introduce the possibility of long-term biological fixation. However, little biomechanical work has been done on the initial stability of these components and the various fixation options. We conducted a study in which all-polyethylene glenoid components with a centrally fluted peg were implanted in polyurethane blocks with interference-fit, hybrid cement, and fully cemented fixation (5 per fixation group). Biomechanical evaluation of glenoid loosening, according to ASTM Standard F-2028-12, subjected the glenoids to 50,000 cycles of rim loading, and glenoid component motion was recorded with 2 differential variable reluctance transducers fixed to each glenoid prosthesis. Fully cemented fixation exhibited significantly less mean distraction in comparison with interference-fit fixation (P < .001) and hybrid cement fixation (P < .001). Hybrid cement fixation exhibited significantly less distraction (P < .001), more compression (P < .001), and no significant difference in glenoid translation (P = .793) in comparison with interference-fit fixation. Fully cemented fixation exhibited the most resistance to glenoid motion in comparison with hybrid cement fixation and interference-fit fixation. However, hybrid cement fixation and interference-fit fixation exhibited equivocal motion. Given these results, cementation of peripheral pegs may confer no additional initial stability over that provided by uncemented interference-fit fixation.

Validation of a new radiographic measurement of acetabular version: the transverse axis distance (TAD).

PubMed

Nitschke, Ashley; Lambert, Jeffery R; Glueck, Deborah H; Jesse, Mary Kristen; Mei-Dan, Omer; Strickland, Colin; Petersen, Brian

2015-11-01

This study has three aims: (1) validate a new radiographic measure of acetabular version, the transverse axis distance (TAD) by showing equivalent TAD accuracy in predicting CT equatorial acetabular version when compared to a previously validated, but more cumbersome, radiographic measure, the p/a ratio; (2) establish predictive equations of CT acetabular version from TAD; (3) calculate a sensitive and specific cut point for predicting excessive CT acetabular anteversion using TAD. A 14-month retrospective review was performed of patients who had undergone a dedicated MSK CT pelvis study and who also had a technically adequate AP pelvis radiograph. Two trained observers measured the radiographic p/a ratio, TAD, and CT acetabular equatorial version for 110 hips on a PACS workstation. Mixed model analysis was used to find prediction equations, and ROC analysis was used to evaluate the diagnostic accuracy of p/a ratio and TAD. CT equatorial acetabular version can accurately be predicted from either p/a ratio (p < 0.001) or TAD (p < 0.001). The diagnostic accuracies of p/a ratio and TAD are comparable (p =0.46). Patients whose TAD is higher than 17 mm may have excessive acetabular anteversion. For that cutpoint, the sensitivity of TAD is 0.73, with specificity of 0.82. TAD is an accurate radiographic predictor of CT acetabular anteversion and provides an easy-to-use and intuitive point-of-care assessment of acetabular version in patients with hip pain.

Wear versus Thickness and Other Features of 5-Mrad Crosslinked UHMWPE Acetabular Liners

PubMed Central

Shen, Fu-Wen; Lu, Zhen

2010-01-01

Background The low wear rates of crosslinked polyethylenes provide the potential to use larger diameters to resist dislocation. However, this requires the use of thinner liners in the acetabular component, with concern that higher contact stresses will increase wear, offsetting the benefits of the crosslinking. Questions/purposes We asked the following questions: Is the wear of conventional and crosslinked polyethylene liners affected by ball diameter, rigidity of backing, and liner thickness? Are the stresses in the liner affected by thickness? Methods Wear rates were measured in a hip simulator and stresses were calculated using finite element modeling. Results Without crosslinking, the wear rate was 4% to 10% greater with a 36-mm diameter than a 28-mm diameter. With crosslinking, wear was 9% lower with a 36-mm diameter without metal backing and 4% greater with metal backing. Reducing the thickness from 6 mm to 3 mm increased the contact stress by 46%, but the wear rate decreased by 19%. Conclusions The reduction in wear with 5 Mrad of crosslinking was not offset by increasing the diameter from 28 mm to 36 mm or by using a liner as thin as 3 mm. Clinical Relevance The results indicate, for a properly positioned 5-Mrad crosslinked acetabular component and within the range of dimensions evaluated, neither wear nor stresses in the polyethylene are limiting factors in the use of larger-diameter, thinner cups to resist dislocation. PMID:20848244

The effect of acetabular cup size on the short-term stability of revision hip arthroplasty: a finite element investigation.

PubMed

Phillips, A T M; Pankaj; Usmani, A S; Howie, C R

2004-01-01

The study uses idealized two-dimensional finite element models to examine the behaviour of the acetabular construct following revision hip arthroplasty, carried out using the Slooff-Ling impaction grafting technique. The behaviour of bone graft was considered in detail, with non-linear elasticity and non-associated plasticity being adopted. Load was applied to the acetabular construct through a femoral head using smooth sliding surfaces. In particular, four models were subjected to two idealized cyclic load cases to investigate the effect of acetabular cup size on the short-term stability of the acetabular construct. The study suggests that benefits may be gained by using the largest practical size of acetabular cup.

Avascular Necrosis of Acetabulum: The Hidden Culprit of Resistant Deep Wound Infection and Failed Fixation of Fracture Acetabulum - A Case Report.

PubMed

K, Kandhari V; M, Desai M; S, Bava S; N, Wade R

2015-01-01

Chances of avascular necrosis of acetabulum are rare as it enjoys a rich blood supply. But cases of post - traumatic avascular necrosis of acetabulum following fracture of posterior column have been well documented. Importance of identifying and suspecting the avascular necrosis of acetabulum is essential in cases of failed fixation of fracture acetabulum, previously operated using extensile approach to acetabulum; either extended anterior ilio - femoral or tri - radiate approach. Such patients usually present with repeated deep bone infection or with early failure of fixation with aseptic loosening and migration of its components. We present a similar case. 40 years female presented with inadequately managed transverse fracture of left acetabulum done by anterior extended ilio-inguinal approach. The fixation failed. She presented 6 months later with painful hip. Cemented total hip replacement was performed with reconstruction of acetabulum by posterior column plating. Six months postoperatively patient presented with dislodgement of cup, pelvic discontinuity and sinus in the thigh. Two stage revision surgery was planned. First implant, removal; debridement and antibiotic spacer surgery was performed. At second stage of revision total hip replacement, patient had Paprosky grade IIIb defect in acetabulum. Spacer was removed through the posterior approach. Anterior approach was taken for anterior plating. Intra-operatively external iliac pulsations were found to be absent so procedure was abandoned after expert opinion. Postoperatively digital subtraction angiography demonstrated a chronic block in the external iliac artery and corona mortis was the only patent vascular channel providing vascular to the left lower limb. Thus, peripheral limb was stealing blood supply from the acetabulum to maintain perfusion. Patient was ultimately left with pelvic discontinuity, excision arthroplasty and pseudoarthrosis of the left hip. Avascular necrosis of acetabulum is a rare entity & often not recognized. One should be suspicious about diagnosis of avascular necrosis of acetabulum in select cases of failed acetabular fixation, previously operated via extensile anterior ilio - inguinal approach. Angiographic evaluation is essential in revision cases of failed acetabular fixation. Corona mortis (crown or circle of death) can sometimes act as a savior of limb.

A novel method to assess primary stability of press-fit acetabular cups.

PubMed

Crosnier, Emilie A; Keogh, Patrick S; Miles, Anthony W

2014-11-01

Initial stability is an essential prerequisite to achieve osseointegration of press-fit acetabular cups in total hip replacements. Most in vitro methods that assess cup stability do not reproduce physiological loading conditions and use simplified acetabular models with a spherical cavity. The aim of this study was to investigate the effect of bone density and acetabular geometry on cup stability using a novel method for measuring acetabular cup micromotion. A press-fit cup was inserted into Sawbones(®) foam blocks having different densities to simulate normal and osteoporotic bone variations and different acetabular geometries. The stability of the cup was assessed in two ways: (a) measurement of micromotion of the cup in 6 degrees of freedom under physiological loading and (b) uniaxial push-out tests. The results indicate that changes in bone substrate density and acetabular geometry affect the stability of press-fit acetabular cups. They also suggest that cups implanted into weaker, for example, osteoporotic, bone are subjected to higher levels of micromotion and are therefore more prone to loosening. The decrease in stability of the cup in the physiological model suggests that using simplified spherical cavities to model the acetabulum over-estimates the initial stability of press-fit cups. This novel testing method should provide the basis for a more representative protocol for future pre-clinical evaluation of new acetabular cup designs. © IMechE 2014.

Acetabular fractures in the elderly treated with a primary Burch-Schneider reinforcement ring, autologous bone graft, and a total hip arthroplasty: a prospective study with a 4-year follow-up.

PubMed

Enocson, Anders; Blomfeldt, Richard

2014-06-01

To investigate the clinical and radiologic outcomes in elderly patients suffering from an acetabular fracture operated with an acute primary acetabular reinforcement ring, autologous bone graft, and a total hip arthroplasty (THA). Prospective cohort study. Tertiary care university hospital. Fifteen elderly patients (7 women) with a mean age of 76 years and a displaced acetabular fracture after a low-energy trauma were included. The fractures involved the anterior column, but no patients with associated both column fractures were included. All the patients were able to walk independently before the fracture occurred. Primary operation with a Burch-Schneider reinforcement ring, autologous bone graft, and a THA. The patients were reviewed at 4, 12, 24, and 48 months after the fracture occurred. The outcome assessments included complications, reoperations, activity of daily living function, functional scores (Harris hip score and short musculoskeletal function assessment), health-related quality of life [EuroQol (EQ-5D) index score], and radiologic evaluation. There were no prosthetic dislocations, periprosthetic fractures, deep infections, or other adverse events. There were no radiologic signs of loosening of the reinforcement ring or the prosthesis components at any of the follow up sessions, and the autologous bone graft was well incorporated in all the patients at the final follow-up. At 48 months, the mean Harris hip score was 88, the mean short musculoskeletal function assessment dysfunction score was 30, the bother score was 25, and the mean EQ-5D index score was 0.65. All the patients were able to walk independently at the final follow-up. Treatment of displaced anterior column, anterior column posterior hemitransverse and transverse acetabular fractures in elderly patients using a primary reinforcement ring, autologous bone graft, and a THA seems to be a safe option with good functional and radiologic outcomes. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Effect of acetabular cup abduction angle on wear of ultrahigh-molecular-weight polyethylene in hip simulator testing.

PubMed

Korduba, Laryssa A; Essner, Aaron; Pivec, Robert; Lancin, Perry; Mont, Michael A; Wang, Aiguo; Delanois, Ronald E

2014-10-01

The effect of acetabular component positioning on the wear rates of metal-on-polyethylene articulations has not been extensively studied. Placement of acetabular cups at abduction angles of more than 40° has been noted as a possible reason for early failure caused by increased wear. We conducted a study to evaluate the effects of different acetabular cup abduction angles on polyethylene wear rate, wear area, contact pressure, and contact area. Our in vitro study used a hip joint simulator and finite element analysis to assess the effects of cup orientation at 4 angles (0°, 40°, 50°, 70°) on wear and contact properties. Polyethylene bearings with 28-mm cobalt-chrome femoral heads were cycled in an environment mimicking in vivo joint fluid to determine the volumetric wear rate after 10 million cycles. Contact pressure and contact area for each cup abduction angle were assessed using finite element analysis. Results were correlated with cup abduction angles to determine if there were any differences among the 4 groups. The inverse relationship between volumetric wear rate and acetabular cup inclination angle demonstrated less wear with steeper cup angles. The largest abduction angle (70°) had the lowest contact area, largest contact pressure, and smallest head coverage. Conversely, the smallest abduction angle (0°) had the most wear and most head coverage. Polyethylene wear after total hip arthroplasty is a major cause of osteolysis and aseptic loosening, which may lead to premature implant failure. Several studies have found that high wear rates for cups oriented at steep angles contributed to their failure. Our data demonstrated that larger cup abduction angles were associated with lower, not higher, wear. However, this potentially "protective" effect is likely counteracted by other complications of steep cup angles, including impingement, instability, and edge loading. These factors may be more relevant in explaining why implants fail at a higher rate if cups are oriented at more than 40° of abduction.

The effect of dynamic hip motion on the micromotion of press-fit acetabular cups in six degrees of freedom.

PubMed

Crosnier, Emilie A; Keogh, Patrick S; Miles, Anthony W

2016-08-01

The hip joint is subjected to cyclic loading and motion during activities of daily living and this can induce micromotions at the bone-implant interface of cementless total hip replacements. Initial stability has been identified as a crucial factor to achieve osseointegration and long-term survival. Whilst fixation of femoral stems achieves good clinical results, the fixation of acetabular components remains a challenge. In vitro methods assessing cup stability keep the hip joint in a fixed position, overlooking the effect of hip motion. The effect of hip motion on cup micromotion using a hip motion simulator replicating hip flexion-extension and a six degrees of freedom measurement system was investigated. The results show an increase in cup micromotion under dynamic hip motion compared to Static Flexion. This highlights the need to incorporate hip motion and measure all degrees of freedom when assessing cup micromotion. In addition, comparison of two press-fit acetabular cups with different surface coatings suggested similar stability between the two cups. This new method provides a basis for a more representative protocol for future pre-clinical evaluation of different cup designs. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

How Reliable is the Acetabular Cup Position Assessment from Routine Radiographs?

PubMed Central

Carvajal Alba, Jaime A.; Vincent, Heather K.; Sodhi, Jagdeep S.; Latta, Loren L.; Parvataneni, Hari K.

2017-01-01

Abstract Background: Cup position is crucial for optimal outcomes in total hip arthroplasty. Radiographic assessment of component position is routinely performed in the early postoperative period. Aims: The aims of this study were to determine in a controlled environment if routine radiographic methods accurately and reliably assess the acetabular cup position and to assess if there is a statistical difference related to the rater’s level of training. Methods: A pelvic model was mounted in a spatial frame. An acetabular cup was fixed in different degrees of version and inclination. Standardized radiographs were obtained. Ten observers including five fellowship-trained orthopaedic surgeons and five orthopaedic residents performed a blind assessment of cup position. Inclination was assessed from anteroposterior radiographs of the pelvis and version from cross-table lateral radiographs of the hip. Results: The radiographic methods used showed to be imprecise specially when the cup was positioned at the extremes of version and inclination. An excellent inter-observer reliability (Intra-class coefficient > 0,9) was evidenced. There were no differences related to the level of training of the raters. Conclusions: These widely used radiographic methods should be interpreted cautiously and computed tomography should be utilized in cases when further intervention is contemplated. PMID:28852355

Acetabular inclination and anteversion in infants using 3D MR imaging.

PubMed

Falliner, A; Muhle, C; Brossmann, J

2002-03-01

To establish if 3D MR imaging could be used for measurements of acetabular inclination and anteversion in infants specimens. 3D MR data of 3 pelvic preparations of 6-week- to 10-month-old infant specimens was gathered. MR imaging in transaxial and frontal planes was carried out to measure the acetabular inclination and anteversion: a method to determine the MR planes for measurements is described. It was oriented on anatomical landmarks of the pelvis and therefore allowed adjustment of the frontal and transaxial planes, independent of the pelvis position. The mean acetabular inclination angle was 48 degrees, and the mean acetabular anteversion was 23 degrees. Because of the low number of cases the results can only be assessed as a tendency, but MR imaging seems to be suitable for measurements of acetabular inclination and anteversion.

Creep and fatigue behavior of a novel 2-component paste-like formulation of acrylic bone cements.

PubMed

Köster, Ulrike; Jaeger, Raimund; Bardts, Mareike; Wahnes, Christian; Büchner, Hubert; Kühn, Klaus-Dieter; Vogt, Sebastian

2013-06-01

The fatigue and creep performance of two novel acrylic bone cement formulations (one bone cement without antibiotics, one with antibiotics) was compared to the performance of clinically used bone cements (Osteopal V, Palacos R, Simplex P, SmartSet GHV, Palacos R+G and CMW1 with Gentamicin). The preparation of the novel bone cement formulations involves the mixing of two paste-like substances in a static mixer integrated into the cartridge which is used to apply the bone cement. The fatigue performance of the two novel bone cement formulations is comparable to the performance of the reference bone cements. The creep compliance of the bone cements is significantly influenced by the effects of physical ageing. The model parameters of Struik's creep law are used to compare the creep behavior of different bone cements. The novel 2-component paste-like bone cement formulations are in the group of bone cements which exhibit a higher creep resistance.

Is the rate of revision of 36 mm metal-on-metal total hip arthroplasties with Pinnacle acetabular components related to the year of the initial operation? an interrupted time-series analysis using data from the National Joint Registry for England and Wales.

PubMed

Matharu, G S; Hunt, L P; Murray, D W; Howard, P; Pandit, H G; Blom, A W; Bolland, B; Judge, A

2018-01-01

The aim of this study was to determine whether the rates of revision for metal-on-metal (MoM) total hip arthroplasties (THAs) with Pinnacle components varied according to the year of the initial operation, and compare these with the rates of revision for other designs of MoM THA. Data from the National Joint Registry for England and Wales included 36 mm MoM THAs with Pinnacle acetabular components which were undertaken between 2003 and 2012 with follow-up for at least five years (n = 10 776) and a control group of other MoM THAs (n = 13 817). The effect of the year of the primary operation on all-cause rates of revision was assessed using Cox regression and interrupted time-series analysis. For MoM THAs involving Pinnacle components, those undertaken between 2007 and 2012 had higher rates of revision compared with those undertaken between 2004 and 2006 (hazard ratio (HR) 2.01; 95% confidence interval (CI) 1.57 to 2.57; p < 0.001). For THAs undertaken during and after 2007, the number of revisions per 1000 implant-years at risk significantly increased by 5.20 (95% CI 0.52 to 9.89; p = 0.033) compared with those undertaken before this time. In the control group, THAs undertaken between 2007 and 2012 also had higher rates of revision (HR 1.77; 95% CI 1.49 to 2.10; p < 0.001), with revisions per 1000 implant-years for those undertaken during and after 2007 significantly increasing by 6.13 (95% CI 1.42 to 10.83; p = 0.016). The five-year revision rates were significantly increased for all primary MoM THAs undertaken from 2007 onwards. Contrary to recent reports, this finding was not specific to those involving Pinnacle acetabular components and may be explained by increased surveillance and recent lowering of the threshold for revision. Cite this article: Bone Joint J 2018;100-B:33-41. ©2018 The British Editorial Society of Bone & Joint Surgery.

Periacetabular Osteotomy Provides Higher Survivorship Than Rim Trimming for Acetabular Retroversion.

PubMed

Zurmühle, Corinne A; Anwander, Helen; Albers, Christoph E; Hanke, Markus S; Steppacher, Simon D; Siebenrock, Klaus A; Tannast, Moritz

2017-04-01

Acetabular retroversion can cause impaction-type femoroacetabular impingement leading to hip pain and osteoarthritis. It can be treated by anteverting periacetabular osteotomy (PAO) or acetabular rim trimming with refixation of the labrum. There is increasing evidence that acetabular retroversion is a rotational abnormality of the entire hemipelvis and not a focal overgrowth of the anterior acetabular wall, which favors an anteverting PAO. However, it is unknown if this larger procedure would be beneficial in terms of survivorship and Merle d'Aubigné scores in a midterm followup compared with rim trimming. We asked if anteverting PAO results in increased survivorship of the hip compared with rim trimming through a surgical hip dislocation in patients with symptomatic acetabular retroversion. We performed a retrospective, comparative study evaluating the midterm survivorship of two matched patient groups with symptomatic acetabular retroversion undergoing either anteverting PAO or acetabular rim trimming through a surgical hip dislocation. Acetabular retroversion was defined by a concomitantly present positive crossover, posterior wall, and ischial spine sign. A total of 279 hips underwent a surgical intervention for acetabular retroversion at our center between 1997 and 2012 (166 periacetabular osteotomies, 113 rim trimmings through surgical hip dislocation). A total of 99 patients (60%) were excluded from the PAO group and 56 patients (50%) from the rim trimming group because they had any of several prespecified conditions (eg, dysplasia or pediatric conditions 61 [37%] for the PAO group and two [2%] for the rim trimming group), matching (10 [6%]/10 [9%] hips), deficient records (10 [6%]/13 [12%] hips), or the patient declined or was lost to followup (18 [11%]/31 [27%] hips). This left 67 hips (57 patients) that underwent anteverting PAO and 57 hips (52 patients) that had acetabular rim trimming. The two groups did not differ in terms of age, sex, body mass index, preoperative ROM, preoperative Merle d'Aubigné-Postel score, radiographic morphology of the acetabulum (except total and anterior acetabular coverage), alpha angle, Tönnis grade of osteoarthritis, and labral and chondral lesions on the preoperative MRI. During the period in question, we generally performed PAO from 1997 to 2003. With the availability of surgical hip dislocation and labral refixation, we generally performed rim trimming from 2004 to 2010. With growing knowledge of the underlying pathomorphology, anteverting PAOs became more common again around 2007 to 2008. A minimum followup of 2 years was required for this study. Failures were included at any time. The median followup for the anteverting PAO group was 9.5 years (range, 2-17.4 years) and 6.8 years (range, 2.2-10.5 years) for the rim trimming group (p < 0.001). Kaplan-Meier survivorship analysis was performed using the following endpoints at 5 and 10 years: THA, radiographic progression of osteoarthritis by one Tönnis grade, and/or Merle d'Aubigné-Postel score < 15 points. Although the 5-year survivorship of the two groups was not different with the numbers available (86% [95% confidence interval {CI}, 76%-94%] for anteverting PAO versus 86% [95% CI, 76%-96%] for acetabular rim trimming), we found increased survivorship at 10 years in hips undergoing anteverting PAO for acetabular retroversion (79% [95% CI, 68%-90%]) compared with acetabular rim trimming (23% [95% CI, 6%-40%]) at 10 years (p < 0.001). The drop in the survivorship curve for the acetabular rim trimming through surgical hip dislocation group started at Year 6. The main reason for failure was a decreased Merle d'Aubigné score. Anteverting PAO may be the more appropriate treatment for hips with substantial acetabular retroversion. This may be the result of reduction of an already smaller lunate surface of hips with acetabular retroversion through rim trimming. However, rim trimming may still benefit hips with acetabular retroversion in which only one or two of the three signs are positive. Future randomized studies should compare these treatments. Level III, therapeutic study.

Influence of bone density on the cement fixation of femoral hip resurfacing components.

PubMed

Bitsch, Rudi G; Jäger, Sebastian; Lürssen, Marcus; Loidolt, Travis; Schmalzried, Thomas P; Clarius, Michael

2010-08-01

In clinical outcome studies, small component sizes, female gender, femoral shape, focal bone defects, bad bone quality, and biomechanics have been associated with failures of resurfacing arthroplasties. We used a well-established experimental setup and human bone specimens to analyze the effects of bone density on cement fixation of femoral hip resurfacing components. Thirty-one fresh frozen femora were prepared for resurfacing using the original instruments. ASR resurfacing prostheses were implanted after dual-energy X-ray densitometer scans. Real-time measurements of pressure and temperature during implantation, analyses of cement penetration, and measurements of micro motions under torque application were performed. The associations of bone density and measurement data were examined calculating regression lines and multiple correlation coefficients; acceptability was tested with ANOVA. We found significant relations between bone density and micro motion, cement penetration, cement mantle thickness, cement pressure, and interface temperature. Mean bone density of the femora was 0.82 +/- 0.13 g/cm(2), t-score was -0.7 +/- 1.0, and mean micro motion between bone and femoral resurfacing component was 17.5 +/- 9.1 microm/Nm. The regression line between bone density and micro motion was equal to -56.7 x bone density + 63.8, R = 0.815 (p < 0.001). Bone density scans are most helpful for patient selection in hip resurfacing, and a better bone quality leads to higher initial component stability. A sophisticated cementing technique is recommended to avoid vigorous impaction and incomplete seating, since increasing bone density also results in higher cement pressures, lower cement penetration, lower interface temperatures, and thicker cement mantles. Copyright 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Posterosuperior Placement of a Standard-Sized Cup at the True Acetabulum in Acetabular Reconstruction of Developmental Dysplasia of the Hip With High Dislocation.

PubMed

Xu, Jiawei; Xu, Chen; Mao, Yuanqing; Zhang, Jincheng; Li, Huiwu; Zhu, Zhenan

2016-06-01

We sought to evaluate posterosuperior placement of the acetabular component at the true acetabulum during acetabular reconstruction in patients with Crowe type-IV developmental dysplasia of the hip. Using pelvic computed tomography and image processing, we developed a two-dimensional mapping technique to demonstrate the distribution of preoperative three-dimensional cup coverage at the true acetabulum, determined the postoperative location of the acetabular cup, and calculated postoperative three-dimensional coverage for 16 Crowe type-IV dysplastic hips in 14 patients with a mean age of 52 years (33-78 years) who underwent total hip arthroplasty. Mean follow-up was 6.3 years (5.5-7.3 years). On preoperative mapping, the maximum three-dimensional coverage using a 44-mm cup was 87.31% (77.36%-98.14%). Mapping enabled the successful replacement of 16 hips using a mean cup size of 44.13 mm (42-46 mm) with posterosuperior placement of the cup. Early weight-bearing and no prosthesis revision or loosening during follow-up were achieved in all patients. The postoperative two-dimensional coverage on anteroposterior radiographs and three-dimensional coverage were 96.15% (89.49%-100%) and 83.42% (71.81%-98.50%), respectively. This technique may improve long-term implant survival in patients with Crowe-IV developmental dysplasia of the hip undergoing total hip arthroplasty by allowing the use of durable bearings, increasing host bone coverage, ensuring initial stability, and restoring the normal hip center. Copyright © 2015 Elsevier Inc. All rights reserved.

Cemented total knee replacement in 24 dogs: surgical technique, clinical results, and complications.

PubMed

Allen, Matthew J; Leone, Kendall A; Lamonte, Kimberly; Townsend, Katy L; Mann, Kenneth A

2009-07-01

To characterize the performance of cemented total knee replacement (TKR) in dogs. Preclinical research study. Skeletally mature, male Hounds (25-30 kg; n=24) with no preexisting joint pathology. Dogs had unilateral cemented TKR and were evaluated at 6, 12, 26, or 52 weeks (6 dogs/time point) by radiography, bone density analysis, visual gait assessment, and direct measurement of thigh circumference and stifle joint range of motion as indicators of functional recovery. At study end, the stability of the cemented tibial component was determined by destructive mechanical testing. Joint stability was excellent in 16 dogs (67%) and good in 8 dogs. None of the tibial components had evidence of migration or periprosthetic osteolysis whereas 1 femoral component was loose at 52 weeks. There was an early and significant decrease in tibial bone density, likely because of disuse of the operated limb. Dogs returned to full activity by 12 weeks. The tibial cement-bone interface maintained its strength over 52 weeks. Cement provides stable fixation of the tibial component in canine TKR. Cemented TKR yields adequate clinical function and stifle joint excursion in the dog. Clinical studies are needed to determine the long-term fate of cemented TKR implants, to assess the influence of implant design on implant fixation and wear, and to obtain objective functional data.

Sacroiliac joint dysfunction as a reason for the development of acetabular retroversion: a new theory.

PubMed

Cibulka, Michael T

2014-05-01

Acetabular retroversion has been recently implicated as an important factor in the development of femoral acetabular impingement and hip osteoarthritis. The proper function of the hip joint requires that the anatomic features of the acetabulum and femoral head complement one another. In acetabular retroversion, the alignment of the acetabulum is altered where it opens in a posterolaterally instead of anterior direction. Changes in acetabular orientation can occur with alterations in pelvic tilt (anterior/posterior), and pelvic rotation (left/right). An overlooked problem that alters pelvic tilt and rotation, often seen by physical therapists, is sacroiliac joint dysfunction. A unique feature that develops in patients with sacroiliac joint dysfunction (SIJD) is asymmetry between the left and right innominate bones that can alter pelvic tilt and rotation. This article puts forth a theory suggesting that acetabular retroversion may be produced by sacroiliac joint dysfunction.

Computer assisted surgery in preoperative planning of acetabular fracture surgery: state of the art.

PubMed

Boudissa, Mehdi; Courvoisier, Aurélien; Chabanas, Matthieu; Tonetti, Jérôme

2018-01-01

The development of imaging modalities and computer technology provides a new approach in acetabular surgery. Areas covered: This review describes the role of computer-assisted surgery (CAS) in understanding of the fracture patterns, in the virtual preoperative planning of the surgery and in the use of custom-made plates in acetabular fractures with or without 3D printing technologies. A Pubmed internet research of the English literature of the last 20 years was carried out about studies concerning computer-assisted surgery in acetabular fractures. The several steps for CAS in acetabular fracture surgery are presented and commented by the main author regarding to his personal experience. Expert commentary: Computer-assisted surgery in acetabular fractures is still initial experiences with promising results. Patient-specific biomechanical models considering soft tissues should be developed to allow a more realistic planning.

Acetabular overcoverage in the horizontal plane: an underdiagnosed trigger of early hip arthritis. A CT scan study in young adults.

PubMed

Valera, Màrius; Ibáñez, Natalia; Sancho, Rogelio; Llauger, Jaume; Gich, Ignasi

2018-01-01

Acetabular overcoverage promotes hip osteoarthritis causing a pincer-type femoroacetabular impingement. Acetabular coverage in the horizontal plane is usually poorly defined in imaging studies and may be misdiagnosed. The goal of this study was to analyze the role of acetabular overcoverage measured in the frontal plane and in the horizontal plane by CT scan and to determine its relationship with other anatomic features in the onset of hip arthritis in young adults. We compared prospectively CT scans from two groups of adults of 55 years or younger: the patient group (n = 30) consisted of subjects with diagnosis of early hip arthritis (Tönnis Grade I or II) and the control group (n = 31) consisted of subjects with healthy hips. Two independent observers analyzed centre edge angle (CEA), acetabular anteversion angle (AAA), anterior sector acetabular angle (AASA), posterior sector acetabular angle (PASA), horizontal acetabular sector angle (HASA), femoral anteversion angle (FAVA), alpha angle (AA), and Mckibbin Instability Index (MI). Angles measuring the acetabular coverage on the horizontal plane (AASA, PASA and, HASA) were significantly higher in the patient group (p < 0.001, p = 0.03 and p < 0.001, respectively). Pearson's correlation coefficient showed a positive correlation between CEA and HASA in patients (r = 0.628) and in controls (r = 0.660). However, a high CEA (> 35º) was strongly associated with a high HASA (> 160º) in patients (p = 0.024) but not in controls (p = 0.21), suggesting that pincer should be simultaneously present in the horizontal and frontal plane to trigger hip degeneration. No significant association was detected between a high alpha angle (> 60º) and a high CEA (> 35º suggesting that a mixed pincer-cam aetiology was not prevalent in our series. Multivariate regression analysis showed the most significant predictors of degenerative joint disease were HASA (p = 0.008), AA (p = 0.048) and ASAA (p = 0.004). Acetabular overcoverage in the horizontal plane plays an important role in the onset of early hip arthritis. Considering that this condition is usually underdiagnosed, we suggest the anterior sector acetabular angle, the posterior sector acetabular angle, and the horizontal acetabular sector angles be routinely included in decision-making algorithms in hip conservative surgery to better define hips-at-risk of developing early hip osteoarthritis.

[Application of three-dimensional printing personalized acetabular wing-plate in treatment of complex acetabular fractures via lateral-rectus approach].

PubMed

Mai, J G; Gu, C; Lin, X Z; Li, T; Huang, W Q; Wang, H; Tan, X Y; Lin, H; Wang, Y M; Yang, Y Q; Jin, D D; Fan, S C

2017-03-01

Objective: To investigate reduction and fixation of complex acetabular fractures using three-dimensional (3D) printing technique and personalized acetabular wing-plate via lateral-rectus approach. Methods: From March to July 2016, 8 patients with complex acetabular fractures were surgically managed through 3D printing personalized acetabular wing-plate via lateral-rectus approach at Department of Orthopedics, the Third Affiliated Hospital of Southern Medical University. There were 4 male patients and 4 female patients, with an average age of 57 years (ranging from 31 to 76 years). According to Letournel-Judet classification, there were 2 anterior+ posterior hemitransverse fractures and 6 both-column fractures, without posterior wall fracture or contralateral pelvic fracture. The CT data files of acetabular fracture were imported into the computer and 3D printing technique was used to print the fractures models after reduction by digital orthopedic technique. The acetabular wing-plate was designed and printed with titanium. All fractures were treated via the lateral-rectus approach in a horizontal position after general anesthesia. The anterior column and the quadrilateral surface fractures were fixed by 3D printing personalized acetabular wing-plate, and the posterior column fractures were reduction and fixed by antegrade lag screws under direct vision. Results: All the 8 cases underwent the operation successfully. Postoperative X-ray and CT examination showed excellent or good reduction of anterior and posterior column, without any operation complications. Only 1 case with 75 years old was found screw loosening in the pubic bone with osteoporosis after 1 month's follow-up, who didn't accept any treatment because the patient didn't feel discomfort. According to the Matta radiological evaluation, the reduction of the acetabular fracture was rated as excellent in 3 cases, good in 4 cases and fair in 1 case. All patients were followed up for 3 to 6 months and all patients had achieved bone union. According to the modified Merle D'Aubigné and Postel scoring system, 5 cases were excellent, 2 cases were good, 1 case was fair. Conclusions: Surgical management of complex acetabular fracture via lateral-rectus approach combine with 3D printing personalized acetabular wing-plate can effectively improve reduction quality and fixation effect. It will be truly accurate, personalized and minimally invasive.

Outcomes of Modified Harrington Reconstructions for Nonprimary Periacetabular Tumors: An Effective and Inexpensive Technique.

PubMed

Bernthal, Nicholas M; Price, Shawn L; Monument, Michael J; Wilkinson, Brandon; Jones, Kevin B; Randall, R Lor

2015-11-01

Metastatic disease to the acetabulum presents a difficult technical and philosophical challenge: complicated surgeries in patients with often short life expectancies force us to examine both the outcome and cost of these operations. Therefore, we studied the durability of a cement-screw rebar reconstruction technique and risk factors for failure, and we compare the results to other reconstruction options. This is a retrospective review of 52 acetabular reconstructions in 50 patients for nonprimary disease using a retrograde screw-rebar-cement all-polyethylene technique. Mean age was 57 years (range 25-81 years). Twenty-four lesions were classified as Harrington class II; 28 were Harrington class III. Mean follow-up was 17.7 months (range 1-92 months). Outcomes included patient survival, prosthesis survival, and complications. Forty-eight of 50 (96 %) patients ambulated after surgery. Five of 52 (9.6 %) of prostheses failed, three from loosening due to tumor progression, one from aseptic loosening, and one from soft tissue instability (dislocation). The three cases of tumor progression failure occurred in patients with massive preoperative ischial tumor burden. Mean surgical time was 198 min, and hospital stay was 5.2 days. The screw-cement-rebar all-polyethylene cup reconstruction technique is a comparatively successful and inexpensive reconstruction option for treating nonprimary oncologic disease in the acetabulum. All cases of loosening occurred beyond the median patient survival. Surgeons should be wary of massive ischial tumor burden in patients with projected longevity, as it may be associated with implant failure. Surgical time and hospital stay are consistent with historical data for alternative implants, and implant cost is lower.

Hip morphologic measurements in an Egyptian population.

PubMed

Aly, Tarek A

2011-04-11

The study of acetabular morphology has shown that there are geographic differences in the morphology and prevalence of acetabular dysplasia among different ethnic groups. However, few data exist on the shape of the acetabulum in various populations around the world. In this study, we examined samples of pelvic radiographs from Egyptian adults. Acetabular dysplasia in adults is characterized by a shallow and relatively vertical acetabulum.The aim of this study was to examine acetabular morphology to determine the prevalence of hip dysplasia in adult Egyptians. This included 244 adults, 134 men and 110 women between 18 and 60 years, who were used to measure center edge angle, acetabular Sharp angle, acetabular head index on anteroposterior radiographic views of the hip joints, and vertical center anterior margin angle on false profile views. The radiographs were taken of patients with no hip complaints at Tanta University Hospital.The results were statistically studied according to the age, height, and weight of patients. The prevalence of acetabular dysplasia was 2.25% for Egyptian men and 3.6% for women with respect to center edge angles, vertical center anterior margin angle, and acetabular head index.We concluded that gender variations in the morphology of the acetabulum and sex influences geometrical measurements of the acetabulum. Egyptian women were more dysplastic than men using the 4 parameters of hip measurements. There are also racial variations in hip morphology. Copyright 2011, SLACK Incorporated.

Decreased Lumbar Lordosis and Deficient Acetabular Coverage Are Risk Factors for Subchondral Insufficiency Fracture.

PubMed

Jo, Woo Lam; Lee, Woo Suk; Chae, Dong Sik; Yang, Ick Hwan; Lee, Kyoung Min; Koo, Kyung Hoi

2016-10-01

Subchondral insufficiency fracture (SIF) of the femoral head occurs in the elderly and recipients of organ transplantation. Osteoporosis and deficient lateral coverage of the acetabulum are known risk factors for SIF. There has been no study about relation between spinopelvic alignment and anterior acetabular coverage with SIF. We therefore asked whether a decrease of lumbar lordosis and a deficiency in the anterior acetabular coverage are risk factors. We investigated 37 patients with SIF. There were 33 women and 4 men, and their mean age was 71.5 years (59-85 years). These 37 patients were matched with 37 controls for gender, age, height, weight, body mass index and bone mineral density. We compared the lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope, acetabular index, acetabular roof angle, acetabular head index, anterior center-edge angle and lateral center-edge angle. Lumbar lordosis, pelvic tilt, sacral slope, lateral center edge angle, anterior center edge angle, acetabular index and acetabular head index were significantly different between SIF group and control group. Lumbar lordosis (OR = 1.11), lateral center edge angle (OR = 1.30) and anterior center edge angle (OR = 1.27) had significant associations in multivariate analysis. Decreased lumbar lordosis and deficient anterior coverage of the acetabulum are risk factors for SIF as well as decreased lateral coverage of the acetabulum.

[Technology of cementless hip endoprosthetics].

PubMed

Ungethüm, M; Blömer, W

1987-06-01

The success achieved with non-cemented hip arthroplasty depends mainly on the stability of the fixation, the quality of the stabilizing bone being just as important as favourable biomechanical conditions. The results of the intensive research and development with respect to the particular features of a non-cemented hip endoprosthesis can be divided into the following basic categories: Biomechanical aspects with special reference to bone related to the design of the prosthesis; material characteristics, such as fatigue strength, tribology, corrosion resistance, and biocompatibility; and development of new materials and coatings to permit direct bonding of implant and bone. With regard to the stem of hip prostheses, the different design parameters of various types are examined to determine their typical design characteristics, such as bearing surface of the collar, geometry of cross section, anatomically adapted shaping, and surface of the implant forming the contact with the bone. The latter can be divided into macroprofiles and macro- and micro-porous coated surfaces. On the other hand, the methods of cementless fixation of acetabular cups can be primarily divided into conical and spherical screw fixation and pegged fixation with additional macroprofiles of porous surfaces. In a separate study of the biomechanical aspects of screwed sockets, the special importance of socket shape and thread geometry are presented with reference to primary stability and long-term fixation of prostheses.

Effect of Body Mass Index on Digital Templating for Total Hip Arthroplasty.

PubMed

Sershon, Robert A; Diaz, Alejandro; Bohl, Daniel D; Levine, Brett R

2017-03-01

Digital templating is becoming more prevalent in orthopedics. Recent investigations report high accuracy using digital templating in total hip arthroplasty (THA); however, the effect of body mass index (BMI) on templating accuracy is not well described. Digital radiographs of 603 consecutive patients (645 hips) undergoing primary THA by a single surgeon were digitally templated using OrthoView (Jacksonville, FL). A 25-mm metallic sphere was used as a calibration marker. Preoperative digital hip templates were compared with the final implant size. Hips were stratified into groups based on BMI: BMI <30 (315), BMI 30-35 (132), BMI 35-40 (97), and BMI >40 (101). Accuracy between templating and final size did not vary by BMI for acetabular or femoral components. Digital templating was within 2 sizes of the final acetabular and femoral implants in 99.1% and 97.1% of cases, respectively. Digital templating is an effective means of predicting the final size of THA components. BMI does not appear to play a major role in altering THA digital templating accuracy. Copyright © 2016 Elsevier Inc. All rights reserved.

RSA prediction of high failure rate for the uncoated Interax TKA confirmed by meta-analysis.

PubMed

Pijls, Bart G; Nieuwenhuijse, Marc J; Schoones, Jan W; Middeldorp, Saskia; Valstar, Edward R; Nelissen, Rob G H H

2012-04-01

In a previous radiostereometric (RSA) trial the uncoated, uncemented, Interax tibial components showed excessive migration within 2 years compared to HA-coated and cemented tibial components. It was predicted that this type of fixation would have a high failure rate. The purpose of this systematic review and meta-analysis was to investigate whether this RSA prediction was correct. We performed a systematic review and meta-analysis to determine the revision rate for aseptic loosening of the uncoated and cemented Interax tibial components. 3 studies were included, involving 349 Interax total knee arthroplasties (TKAs) for the comparison of uncoated and cemented fixation. There were 30 revisions: 27 uncoated and 3 cemented components. There was a 3-times higher revision rate for the uncoated Interax components than that for cemented Interax components (OR = 3; 95% CI: 1.4-7.2). This meta-analysis confirms the prediction of a previous RSA trial. The uncoated Interax components showed the highest migration and turned out to have the highest revision rate for aseptic loosening. RSA appears to enable efficient detection of an inferior design as early as 2 years postoperatively in a small group of patients.

The boiled-egg technique: a new method for obtaining femoral head autograft used in acetabular defect reconstruction.

PubMed

Bucknall, Vittoria; Mehdi, Ali

2013-09-01

Primary total hip arthroplasty can be complicated by acetabular bony defects, threatening the biomechanical integrity of the prosthesis. Traditionally, when autologous bone is used to pack these defects, it is obtained from thin slices of femoral head in addition to acetabular reamings. We report a novel technique for the acquisition of autologous femoral head bone graft used in the reconstruction of acetabular defects during primary total hip arthroplasty. Copyright © 2013 Elsevier Inc. All rights reserved.

Intraoperative fluoroscopic evaluation of screw placement during pelvic and acetabular surgery.

PubMed

Yi, Chengla; Burns, Sean; Hak, David J

2014-01-01

The surgical treatment of pelvic and acetabular fractures can be technically challenging. Various techniques are available for the reconstruction of pelvic and acetabular fractures. Less invasive percutaneous fracture stabilization techniques, with closed reduction or limited open reduction, have been developed and are gaining popularity in the management of pelvic and acetabular fractures. These techniques require knowledge and interpretation of various fluoroscopic images to ensure appropriate and safe screw placement. Given the anatomic complexity of the intrapelvic structures and the 2-dimensional nature of standard fluoroscopy, multiple images oriented in different planes are needed to assess the accuracy of guide wire and screw placement. This article reviews the fluoroscopic imaging of common screw orientations during pelvic and acetabular surgery.

Influence of Cements Containing Calcareous Fly Ash as a Main Component Properties of Fresh Cement Mixtures

NASA Astrophysics Data System (ADS)

Gołaszewski, Jacek; Kostrzanowska-Siedlarz, Aleksandra; Ponikiewski, Tomasz; Miera, Patrycja

2017-10-01

The main goal of presented research was to examine usability of cements containing calcareous fly ash (W) from technological point of view. In the paper the results of tests concerning the influence of CEM II and CEM IV cements containing fly ash (W) on rheological properties, air content, setting times and plastic shrinkage of mortars are presented and discussed. Moreover, compatibility of plasticizers with cements containing fly ash (W) was also studied. Additionally, setting time and hydration heat of cements containing calcareous fly ash (W) were determined. In a broader aspect, the research contributes to promulgation of the possibility of using calcareous fly ash (W) in cement and concrete technology, what greatly benefits the environment protection (utilization of waste fly ash). Calcareous fly ash can be used successfully as the main component of cement. Cements produced by blending with processed fly ash or cements produced by interginding are characterized by acceptable technological properties. In respect to CEM I cements, cements containing calcareous fly ash worsen workability, decrease air content, delay setting time of mixtures. Cements with calcareous fly ash show good compatibility with plasticizers.

Deformation of the Durom Acetabular Component and Its Impact on Tribology in a Cadaveric Model—A Simulator Study

PubMed Central

Gu, Yanqing; Wang, Qing; Cui, Weiding; Fan, Weimin

2012-01-01

Background Recent studies have shown that the acetabular component frequently becomes deformed during press-fit insertion. The aim of this study was to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the Durom large head metal-on-metal (MOM) total hips in simulators. Methods Six Durom cups impacted into reamed acetabula of fresh cadavers were used as the experimental group and another 6 size-paired intact Durom cups constituted the control group. All 12 Durom MOM total hips were put through a 3 million cycle (MC) wear test in simulators. Results The 6 cups in the experimental group were all deformed, with a mean deformation of 41.78±8.86 µm. The average volumetric wear rate in the experimental group and in the control group in the first million cycle was 6.65±0.29 mm3/MC and 0.89±0.04 mm3/MC (t = 48.43, p = 0.000). The ion levels of Cr and Co in the experimental group were also higher than those in the control group before 2.0 MC. However there was no difference in the ion levels between 2.0 and 3.0 MC. Conclusions This finding implies that the non-modular acetabular component of Durom total hip prosthesis is likely to become deformed during press-fit insertion, and that the deformation will result in increased volumetric wear and increased ion release. Clinical Relevance This study was determined to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the prosthesis. Deformation of the cup after implantation increases the wear of MOM bearings and the resulting ion levels. The clinical use of the Durom large head prosthesis should be with great care. PMID:23144694

[Perioperative complications after total hip revision surgery and their predictive factors. A series of 181 consecutive procedures].

PubMed

de Thomasson, E; Guingand, O; Terracher, R; Mazel, C

2001-09-01

We conducted a retrospective study to assess morbidity and mortality in patients undergoing revision total hip arthroplasty (THA) procedures. Perioperative complications were recorded in 181 revision procedures (162 patients) performed between January 1995 and March 1999 (117 bipolar revisions and 64 acetabular isolated revisions). There were 86 complications (68 patients) leading to 21 new revisions. About half (50/86) were related to the surgical procedure (dislocation, femoral fracture, infection.). Life-threatening complications (3.6%) ended in patient death in 1.6% of the cases. Complications were more frequent in patients with an ASA score=3 (p<0.01) or aged over 75 years (p<0.05). Age was also predictive of femoral misalignment and fracture (p<0.05). Dislocations (8.8%) were observed more frequently in patients who had undergone more than 2 procedures prior to the revision (p<0.05) (4.8% of the dislocations in patients undergoing a first revision procedure and 14.3% in the others). In addition, peroperative blood loss and duration of the procedure were significantly greater in case of bipolar replacement than for isolated acetabular replacement (sigma > 1.96). Our experience and data in the literature point to the important age factor in the development of complications. Preservation of a well-fixed femoral component does not appear to worsen prognosis and leads to fewer complications than bipolar changes. The decision to revise a THA must take into consideration the functional impairment but also the risks inherent in revision procedures, particularly in old patients who have undergone several procedures. Revising the acetabular component alone can be an interesting option if the femoral component remains well-fixed although our follow-up is insufficient to determine whether this attitude provides better long-term outcome than complete biopolar revision. Better patient selection and improved operative technique, in particular in femur preparation, should help reduce morbidity and mortality in this type of procedure.

Deformation of the Durom acetabular component and its impact on tribology in a cadaveric model--a simulator study.

PubMed

Liu, Feng; Chen, Zhefeng; Gu, Yanqing; Wang, Qing; Cui, Weiding; Fan, Weimin

2012-01-01

Recent studies have shown that the acetabular component frequently becomes deformed during press-fit insertion. The aim of this study was to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the Durom large head metal-on-metal (MOM) total hips in simulators. Six Durom cups impacted into reamed acetabula of fresh cadavers were used as the experimental group and another 6 size-paired intact Durom cups constituted the control group. All 12 Durom MOM total hips were put through a 3 million cycle (MC) wear test in simulators. The 6 cups in the experimental group were all deformed, with a mean deformation of 41.78 ± 8.86 µm. The average volumetric wear rate in the experimental group and in the control group in the first million cycle was 6.65 ± 0.29 mm(3)/MC and 0.89 ± 0.04 mm(3)/MC (t = 48.43, p = 0.000). The ion levels of Cr and Co in the experimental group were also higher than those in the control group before 2.0 MC. However there was no difference in the ion levels between 2.0 and 3.0 MC. This finding implies that the non-modular acetabular component of Durom total hip prosthesis is likely to become deformed during press-fit insertion, and that the deformation will result in increased volumetric wear and increased ion release. This study was determined to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the prosthesis. Deformation of the cup after implantation increases the wear of MOM bearings and the resulting ion levels. The clinical use of the Durom large head prosthesis should be with great care.

Development of calcium phosphate cement using chitosan and citric acid for bone substitute materials.

PubMed

Yokoyama, Atsuro; Yamamoto, Satoru; Kawasaki, Takao; Kohgo, Takao; Nakasu, Masanori

2002-02-01

We developed a calcium phosphate cement that could be molded into any desired shape due to its chewing-gum-like consistency after mixing. The powder component of the cement consists of alpha-tricalcium phosphate and tetracalcium phosphate, which were made by decomposition of hydroxyapatite ceramic blocks. The liquid component consists of citric acid, chitosan and glucose solution. In this study, we used 20% citric acid (group 20) and 45% citric acid (group 45). The mechanical properties and biocompatibility of this new cement were investigated. The setting times of cements were 5.5 min, in group 20 and 6.4 min, in group 45. When incubated in physiological saline, the cements were transformed to hydroxyapatite at 3, and 6 weeks, the compressive strengths were 15.6 and 20.7 MPa, in group 45 and group 20, respectively. The inflammatory response around the cement implanted on the bone and in the subcutaneous tissue in rats was more prominent in group 45 than in group 20 at 1 week after surgery. After 4 weeks, the inflammation disappeared and the cement had bound to bone in both groups. These results indicate that this new calcium phosphate cement is a suitable bone substitute material and that the concentration of citric acid in the liquid component affects its mechanical properties and biocompatibility.

Effect of phase composition of calcium silicate phosphate component on properties of brushite based composite cements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sopcak, T., E-mail: tsopcak@imr.saske.sk; Medvecky, L.; Giretova, M.

The composite cement mixtures were prepared by mixing brushite (B) with, the amorphous hydrated calcium silicate phosphate (CSPH) or annealed calcium silicate phosphate (CSP composed of Si-saturated hydroxyapatite, wollastonite and silica) phases and water as liquid component. The contents of the silicate-phosphate phase in composites were 10.30 and 50 wt%. The significant effect of both the Ca/P ratio and different solubility of calcium silicate phosphate component in starting cement systems on setting time and phase composition of the final composite cements was demonstrated. The compressive strength of the set cements increased with the filler addition and the highest value (~more » 48 MPa) exhibited the 50CSP/B cement composite. The final setting times of the composite cements decreased with the CSPH addition from about 25 to 17 min in 50CSHP/B and setting time of CSP/B composites was around 30 min. The higher content of silica in cements caused the precipitation of fine hydroxyapatite particles in the form of nanoneedles or thin plates perpendicularly oriented to sample surface. The analysis of in vitro cement cytotoxicity demonstrated the strong reduction in cytotoxicity of 10CSPH/B composite with time of cultivation (a low cytotoxicity after 9 days of culture) contrary to cements with higher calcium silicate-phosphate content. These results were attributed to the different surface topography of composite substrates and possible stimulation of cell proliferation by the slow continuously release of ions from 10CSPH/B cement. - Highlights: • Ca/P ratio and solubility of calcium silicate-phosphate components affect the self-setting properties of cements. • Strong relationship between the composite in vitro cytotoxicity and surface microtopography was demonstrated. • Plate-like morphology of coarser particles allowed cells to better adhere and proliferate as compared with nanoneedles.« less

EFFECTS OF EPISODIC SUBLUXATION EVENTS ON THIRD BODY INGRESS AND EMBEDMENT IN THE THA BEARING SURFACE

PubMed Central

Heiner, Anneliese D.; Lundberg, Hannah J.; Baer, Thomas E.; Pedersen, Douglas R.; Callaghan, John J.; Brown, Thomas D.

2008-01-01

In total joint arthroplasty, third body particle access to the articulating surfaces results in accelerated wear. Hip joint subluxation is an under-recognized means by which third body particles could potentially enter the otherwise closely conforming articular bearing space. The present study was designed to test the hypothesis that, other factors being equal, even occasional events of femoral head subluxation greatly increase the number of third body particles that enter the bearing space and become embedded in the acetabular liner, as compared to level walking cycles alone. Ten metal-on-polyethylene hip joint head-liner pairs were tested in a multi-axis joint motion simulator, with CoCrMo third body particles added to the synovial fluid analog. All component pairs were tested for two hours of level walking; half also were subjected to twenty intermittent subluxation events. The number and location of embedded particles on the acetabular liners were then determined. Subluxation dramatically increased the number of third body particles embedded in the acetabular liners, and it considerably increased the amount of scratch damage on the femoral heads. Since both third body particles and subluxation frequently occur in contemporary total hip arthroplasty, their potent synergy needs to be factored prominently into strategies to minimize wear. PMID:18561936

Bipolar hip arthroplasty for avascular necrosis of femoral head in young adults

PubMed Central

Dudani, Baldev; Shyam, Ashok K; Arora, Pankush; Veigus, Arjun

2015-01-01

Background: Bipolar hip arthroplasty (BHA) is one of the options for treatment of avascular necrosis (AVN) of the femoral head. Acetabular erosion and groin pain are the most allowing for gross motion between the common complications. We propose that these complications are secondary to improper acetabular preparation allowing for motion between the BHA head and the acetabulum. Materials and Methods: The current study retrospectively evaluated patients’records from case files and also called them for clinical and radiological followup. 96 hips with AVN of the femoral head treated with BHA were included in the study. All patients were males with a mean age of 42 years (range 30-59 years). In all cases, the acetabulum was gently reamed till it became uniformly concentric to achieve tight fitting trial cup. Clinical followup using Harris hip score (HHS) and radiological study for cup migration were done at followup. Results: The mean followup was 7.52 years (range 4-16 years). The HHS significantly improved from a preoperative value of 39.3 (range, 54-30) to a postoperative value of 89.12 (range 74-96). According to HHS grades, the final outcome was excellent in 52 hips, good in 28 and fair in 16 hips. Hip and groin pain was reported in four hips (5%), but did not limit activity. Subsidence (less than 5 mm) of the femoral component was seen in 8 cases. Subgroup analysis showed patients with Ficat Stage 3 having better range of motion, but similar HHS as compared to Ficat Stage 4 patients. Conclusion: Bipolar hip arthroplasty (BHA) using tight fitting cup and acetabular reaming in AVN hip has a low incidence of groin pain, acetabular erosion and revision in midterm followup. Good outcome and mid term survival can be achieved irrespective of the Ficat Stage. PMID:26015634

The results of a proximally-coated cementless femoral component in total hip replacement: a five- to 12-year follow-up.

PubMed

Kim, Y-H

2008-03-01

This study reviewed the results of a cementless anatomical femoral component to give immediate post-operative stability, and with a narrow distal section in order not to contact the femoral cortex in the diaphysis, ensuring exclusively metaphyseal loading. A total of 471 patients (601 hips) who had a total hip replacement between March 1995 and February 2002 were included in the study. There were 297 men and 174 women. The mean age at the time of operation was 52.7 years (28 to 63). Clinical and radiological evaluation were performed at each follow-up. Bone densitometry was carried out on all patients two weeks after operation and at the final follow-up examination. The mean follow-up was 8.8 years (5 to 12). The mean pre-operative Harris hip score was 41 points (16 to 54), which improved to a mean of 96 (68 to 100) at the final follow-up. No patient complained of thigh pain at any stage. No acetabular or femoral osteolysis was observed and no hip required revision for aseptic loosening of either component. Deep infection occurred in two hips (0.3%) which required revision. One hip (0.2%) required revision of the acetabular component for recurrent dislocation. Bone mineral densitometry revealed a minimal bone loss in the proximal femur. This cementless anatomical femoral component with metaphyseal loading but without distal fixation produced satisfactory fixation and encourages proximal femoral loading.

Operative tactics and results of treatment of patients with coxarthrosis secondary to congenital high luxation of hip joints.

PubMed

Król, Roman; Rojewski, Marek; Kamiński, Adam; Popławski, Tomasz

2007-01-01

Treatment of the sequelae of congenital high luxation of the hip joint is a major challenge in prosthetic surgery, demanding from the operator thorough familiarity with the problem and experience in hop reconstructive surgery. The results of 4 years observation, of the treatment of 14 woman in the average age of 38 years old with 18 hip joints with congenital high luxation are presented. In all cases cementless total hip arthroplasty was made. Acetabular component of the prosthesis was implanted correctly and stable in its physiological placement. Femur was shortened average 4 cm and stabilized by cementless press-fit stem of prosthesis. The place of femur osteotomy was covered with autogenic spongy bone from resected caput of femur. The union was achieved after average 10 weeks. In clinical assessment there were obtained 10 very good, 5 good and 3 satisfactory clinical results. There were no superficial or deep infections, no neurological disorders and no loosening of components of implanted prostheses observed. 1. Careful planning and carrying out the operative procedures allow to insert the acetabular component of the prosthesis in its physiological place and achieve good results. 2. Shortening of femur and repositioning of components of prosthesis in 90 degrees knee flexion and also position on broken bed after operative procedure allowed to avoid neurological disorders. 3. Cementless and hydroxyapatite-covered femoral component of the prosthesis correctly stabilize place of femur osteotomy.

Migration and head penetration of Vitamin-E diffused cemented polyethylene cup compared to standard cemented cup in total hip arthroplasty: study protocol for a randomised, double-blind, controlled trial (E1 HIP).

PubMed

Sköldenberg, Olof; Rysinska, Agata; Chammout, Ghazi; Salemyr, Mats; Muren, Olle; Bodén, Henrik; Eisler, Thomas

2016-07-07

In vitro, Vitamin-E-diffused, highly cross-linked polyethylene (PE) has been shown to have superior wear resistance and improved mechanical properties when compared to those of standard highly cross-linked PE liners used in total hip arthroplasty (THA). The aim of the study is to evaluate the safety of a new cemented acetabular cup with Vitamin-E-doped PE regarding migration, head penetration and clinical results. In this single-centre, double-blinded, randomised controlled trial, we will include 50 patients with primary hip osteoarthritis scheduled for THA and randomise them in a 1:1 ratio to a cemented cup with either argon gas-sterilised PE (control group) or Vitamin-E-diffused PE (vitamin-e group). All patients and the assessor of the primary outcome will be blinded and the same uncemented stem will be used for all participants. The primary end point will be proximal migration of the cup at 2 years after surgery measured with radiostereometry. Secondary end points include proximal migration at other follow-ups, total migration, femoral head penetration, clinical outcome scores and hip-related complications. Patients will be followed up at 3 months and at 1, 2, 5 and 10 years postoperatively. Results will be analysed using 95% CIs for the effect size. A regression model will also be used to adjust for stratification factors. The ethical committee at Karolinska Institutet has approved the study. The first results from the study will be disseminated to the medical community via presentations and publications in relevant medical journals when the last patient included has been followed up for 2 years. NCT02254980. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Migration and head penetration of Vitamin-E diffused cemented polyethylene cup compared to standard cemented cup in total hip arthroplasty: study protocol for a randomised, double-blind, controlled trial (E1 HIP)

PubMed Central

Sköldenberg, Olof; Rysinska, Agata; Chammout, Ghazi; Salemyr, Mats; Muren, Olle; Bodén, Henrik; Eisler, Thomas

2016-01-01

Introduction In vitro, Vitamin-E-diffused, highly cross-linked polyethylene (PE) has been shown to have superior wear resistance and improved mechanical properties when compared to those of standard highly cross-linked PE liners used in total hip arthroplasty (THA). The aim of the study is to evaluate the safety of a new cemented acetabular cup with Vitamin-E-doped PE regarding migration, head penetration and clinical results. Methods and analysis In this single-centre, double-blinded, randomised controlled trial, we will include 50 patients with primary hip osteoarthritis scheduled for THA and randomise them in a 1:1 ratio to a cemented cup with either argon gas-sterilised PE (control group) or Vitamin-E-diffused PE (vitamin-e group). All patients and the assessor of the primary outcome will be blinded and the same uncemented stem will be used for all participants. The primary end point will be proximal migration of the cup at 2 years after surgery measured with radiostereometry. Secondary end points include proximal migration at other follow-ups, total migration, femoral head penetration, clinical outcome scores and hip-related complications. Patients will be followed up at 3 months and at 1, 2, 5 and 10 years postoperatively. Results Results will be analysed using 95% CIs for the effect size. A regression model will also be used to adjust for stratification factors. Ethics and dissemination The ethical committee at Karolinska Institutet has approved the study. The first results from the study will be disseminated to the medical community via presentations and publications in relevant medical journals when the last patient included has been followed up for 2 years. Trial registration number NCT02254980. PMID:27388352

Monitoring the quality of total hip replacement in a tertiary care department using a cumulative summation statistical method (CUSUM).

PubMed

Biau, D J; Meziane, M; Bhumbra, R S; Dumaine, V; Babinet, A; Anract, P

2011-09-01

The purpose of this study was to define immediate post-operative 'quality' in total hip replacements and to study prospectively the occurrence of failure based on these definitions of quality. The evaluation and assessment of failure were based on ten radiological and clinical criteria. The cumulative summation (CUSUM) test was used to study 200 procedures over a one-year period. Technical criteria defined failure in 17 cases (8.5%), those related to the femoral component in nine (4.5%), the acetabular component in 32 (16%) and those relating to discharge from hospital in five (2.5%). Overall, the procedure was considered to have failed in 57 of the 200 total hip replacements (28.5%). The use of a new design of acetabular component was associated with more failures. For the CUSUM test, the level of adequate performance was set at a rate of failure of 20% and the level of inadequate performance set at a failure rate of 40%; no alarm was raised by the test, indicating that there was no evidence of inadequate performance. The use of a continuous monitoring statistical method is useful to ensure that the quality of total hip replacement is maintained, especially as newer implants are introduced.

Is anatomic acetabular orientation related to pelvic morphology? CT analysis of 150 healthy pelvises.

PubMed

Sautet, P; Giorgi, H; Chabrand, P; Tropiano, P; Argenson, J-N; Parratte, S; Blondel, B

2018-05-01

Links between sagittal spinal alignment and acetabular orientation attract considerable research attention with the goal of optimising prosthetic cup position. However, whether pelvic incidence (PI) is related to anatomic acetabular orientation remains unknown. We therefore conducted a radiological study with the following objectives: to look for correlations between PI and anatomic acetabular parameters; to describe the sacro-pubic angle (SPA), defined by fixed bony pelvic landmarks, and its relations with acetabular anteversion; and to determine whether anatomical parameters (PI and SPA) correlate with demographic characteristics. PI correlates with anatomical acetabular parameters. We conducted a computed tomography (CT) study of the pelvises of 150 patients free of degenerative disease. Three parameters were measured: anatomic acetabular orientation in the Lewinnek reference plane, PI, and the SPA subtended by the line connecting the midpoint of the sacral endplate to the pubic symphysis and the anterior pelvic plane. Statistical tests were performed to look for correlations among these parameters. Intra-observer and inter-observer reproducibility was considered highly satisfactory (inter-class correlation coefficient, >86% and >82%, respectively). Mean PI was 58.6°±10.2° (range, 32.8°-97.6°), with no significant differences between genders or across age groups. Mean SPA was 34.7°±5.5° (range, 18.3°-49.8°). Mean anatomic acetabular anteversion (AAA) was greater in females (23.4°; range, 11.5°-34.5°) than in males (20°; range, 7.5°-34.5°) (P<0.001). PI did not correlate with any of the acetabular parameters (PI/AAA, r=0.8 and P=0.33; PI/acetabular inclination on the horizontal, r=-0.96 and P=0.24). SPA correlated significantly with both PI (r=0.33 and P<0.001) and AAA (r=0.33 and P<0.001). This CT study of normal pelvises showed that AAA was significantly greater in females and that SPA correlated significantly with both PI and acetabular anteversion. SPA could serve to define the "theoretical" AAA of each individual patient and could thus be incorporated into surgical planning protocols or intra-operative guidance methods for hip replacement surgery. IV, retrospective study with no control group. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Combat-related acetabular fractures: Outcomes of open versus closed injuries.

PubMed

Purcell, Richard L; Donohue, Michael A; Saxena, Sameer K; Gordon, Wade T; Lewandowski, Louis L

2018-02-01

Since the onset of the Global War on Terror close to 50,000 United States service members have been injured in combat, many of these injuries would have previously been fatal. Among these injuries, open acetabular fractures are at an increased number due to the high percentage of penetrating injuries such as high velocity gunshot wounds and blast injuries. These injuries lead to a greater degree of contamination, and more severe associated injuries. There is a significantly smaller proportion of the classic blunt trauma mechanism typically seen in civilian trauma. We performed a retrospective review of the Department of Defense Trauma Registry into which all US combat-injured patients are enrolled, as well as reviewed local patient medical records, and radiologic studies from March 2003 to April 2012. Eighty seven (87) acetabular fractures were identified with 32 classified as open fractures. Information regarding mechanism of injury, fracture pattern, transfusion requirements, Injury Severity Score (ISS), and presence of lower extremity amputations was analyzed. The mechanism of injury was an explosive device in 59% (n=19) of patients with an open acetabular fracture; the remaining 40% (n=13) were secondary to ballistic injury. In contrast, in the closed acetabular fracture cohort 38% (21/55) of fractures were due to explosive devices, and all remaining (n=34) were secondary to blunt trauma such as falls, motor vehicle collisions, or aircraft crashes. Patients with open acetabular fractures required a median of 17units of PRBC within the first 24h after injury. The mean ISS was 32 in the open group compared with 22 in the closed group (p=0.003). In the open fracture group nine patients (28%) sustained bilateral lower extremity amputations, and 10 patients (31%) ultimately underwent a hip disarticulation or hemi-pelvectomy as their final amputation level. Open acetabular fractures represent a significant challenge in the management of combat-related injuries. High ISS and massive transfusion requirements are common in these injuries. This is one of the largest series reported of open acetabular fractures. Open acetabular fractures require immediate damage control surgery and resuscitation as well as prolonged rehabilitation due to their severity. The dramatic number of open acetabular fractures (37%) in this review highlights the challenge in treatment of combat related acetabular fractures. Published by Elsevier Ltd.

[IMAGING ANALYSIS OF ACETABULAR CUP POSITIONS IN TOTAL HIP ARTHROPLASTY FOR ADULTS WITH ACETABULAR DYSPLASIA].

PubMed

Sun, Hong; Fang, Shuying; Yang, Zibo; Zhang, Zhiqi; Kang, Yan; Zhang, Ziji; Liao, Weiming; Fu, Ming; Wu, Peihui

2016-11-08

To investigate the influence of the degree of acetabular deformity and the learning-curve on the acetabular cup positions in total hip arthroplasty (THA) for adults with developmental dysplasia of hip (DDH). Between January 2008 and December 2015, 130 patients (144 hips) with DDH underwent primary THA, and the clinical data were analyzed retrospectively. Fifty-three patients (59 hips) were admitted before 2012, and 77 patients (85 hips) were treated after 2012. There were 32 males and 98 females, aged from 31 to 83 years (mean, 61). Unilateral replacement was performed in 116 cases and bilateral replacement in 14 cases. Of 144 hips, 48 hips were rated as Crowe type I, 57 hips as type II, and 39 hips as type of III/IV. The standard pelvic radiograph was taken within 1 week after operation. The mediCAD software was adopted to measure the angle of anteversion and abduction, bony coverage, and the distance between true rotating center and optimal rotating center to the connection of teardrops and the horizontal distance between two centers to evaluate the qualified rate of acetabular cup positions. Compared with the patients with the same type in 2013-2015 group, the anteversion angle and qualified rate of acetabular cup position significantly decreased in patients with Crowe I ( P <0.05); the horizontal distance significantly increased and qualified rate of acetabular cup position significantly decreased in patients with Crowe II ( P <0.05); and the anteversion angle significantly decreased and the horizontal distance significantly increased in patients with Crowe III/IV ( P <0.05) in 2008-2012 group. But no significant difference was shown in the other indexes ( P >0.05). In all Crowe types, the vertical distance between the true rotating center and the optimal rotating center increased with the degree of acetabular deformity in both 2008-2012 group and 2013-2015 group, showing significant difference ( P <0.05), but no significant difference was found in the other indexes ( P >0.05). For adults with acetabular dysplasia, there are high potential risks for unsatisfactory acetabular cup positions during primary THA. So it is necessary to evaluate acetabular deformities and to sum up operative experience so as to improve the accuracy of cups installation.

Scanning Electron Microscopy and Energy-Dispersive X-Ray Spectroscopy as a Valuable Tool to Investigate the Ultra-High-Molecular-Weight Polyethylene Wear Mechanisms and Debris in Hip Implants.

PubMed

Schappo, Henrique; Gindri, Izabelle M; Cubillos, Patrícia O; Maru, Marcia M; Salmoria, Gean V; Roesler, Carlos R M

2018-01-01

The use of scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS) was investigated to understand the wear mechanisms from a metal-on-polyethylene bearing couple. Morphological features of femoral head acetabular liner, and isolated particles resulting from hip wear testing were evaluated. EDS was proposed to investigate the polymeric nature of the particles isolated from the wear testing. In this work, 28-mm conventional ultra-high-molecular-weight polyethylene acetabular liners paired with metallic heads were tested in a hip wear simulator over 2 million cycles. SEM-EDS was employed to investigate wear mechanisms on hip implant components and associated wear debris. SEM showed worn surfaces for both hip components, and a significant volume of ultra-high-molecular-weight polyethylene wear particles resulting from hip wear testing. Particles were classified into 3 groups, which were then correlated to wear mechanisms. Group I had particles with smooth surfaces, group II consisted of particles with rough surfaces, and group III comprised aggregate-like particles. Group I EDS revealed that particles from groups I and II had a high C/O ratio raising a concern about the particle source. On the other hand, particles from group III had a low C/O ratio, supporting the hypothesis that they resulted from the wear of acetabular liner. Most of particles identified in group III were in the biologically active size range (0.3 to 20 μm). The use of optical and electron microscopy enabled the morphological characterization of worn surfaces and wear debris, while EDS was essential to elucidate the chemical composition of isolated debris. Copyright © 2017 Elsevier Inc. All rights reserved.

Screws are not needed when secure interference fit of uncemented acetabular components is adequate: a 5- to 15-year follow-up with clinical and radiological analysis.

PubMed

García-Rey, Eduardo

2017-05-12

Even with good surgical preparation, adequate primary stability of the acetabular component is not always achieved after primary total hip replacement (THR). We hypothesise that adequate bone preparation for appropriate cortical loading would allow us to avoid screw use. A total of 791 uncemented cups were analysed to compare the need for screws to obtain primary fixation in 5 different designs. Arthritic hips with inflammatory arthritis or severe congenital hip disease were excluded. A press-fit technique was first tried in all hips and screws were only used when strictly needed. Radiological acetabular shape and postoperative cup position were assessed in all hips. The mean follow-up was 9.6 (5-15) years. Screws were required in 155 hips (19.6%). We could not detect any difference in the percentage of screw use between designs. We found that female patients (odds ratio [OR] 2.06; 95% confidence interval [CI], 1.41-3.02) and cups with a greater distance to the hip rotation centre on the postoperative radiograph (OR 1.69; 95% CI, 1.17-2.45) had a higher risk for screw use. A greater anteversion of the cup had a lower risk for screw use (OR 0.96; 95% CI, 0.94-0.99). At latest follow-up no hips had needed revision for aseptic loosening. Good intraoperative technique is not enough to avoid screw use since more accurate cup position and reconstruction of the hip rotation centre are required for an adequate interference fit. A press-fit technique can provide similar mid-term results to screw use in hips without severe deformities.

Predictive Mechanical Characterization of Macro-Molecular Material Chemistry Structures of Cement Paste at Nano Scale - Two-phase Macro-Molecular Structures of Calcium Silicate Hydrate, Tri-Calcium Silicate, Di-Calcium Silicate and Calcium Hydroxide

NASA Astrophysics Data System (ADS)

Padilla Espinosa, Ingrid Marcela

Concrete is a hierarchical composite material with a random structure over a wide range of length scales. At submicron length scale the main component of concrete is cement paste, formed by the reaction of Portland cement clinkers and water. Cement paste acts as a binding matrix for the other components and is responsible for the strength of concrete. Cement paste microstructure contains voids, hydrated and unhydrated cement phases. The main crystalline phases of unhydrated cement are tri-calcium silicate (C3S) and di-calcium silicate (C2S), and of hydrated cement are calcium silicate hydrate (CSH) and calcium hydroxide (CH). Although efforts have been made to comprehend the chemical and physical nature of cement paste, studies at molecular level have primarily been focused on individual components. Present research focuses on the development of a method to model, at molecular level, and analysis of the two-phase combination of hydrated and unhydrated phases of cement paste as macromolecular systems. Computational molecular modeling could help in understanding the influence of the phase interactions on the material properties, and mechanical performance of cement paste. Present work also strives to create a framework for molecular level models suitable for potential better comparisons with low length scale experimental methods, in which the sizes of the samples involve the mixture of different hydrated and unhydrated crystalline phases of cement paste. Two approaches based on two-phase cement paste macromolecular structures, one involving admixed molecular phases, and the second involving cluster of two molecular phases are investigated. The mechanical properties of two-phase macromolecular systems of cement paste consisting of key hydrated phase CSH and unhydrated phases C3S or C2S, as well as CSH with the second hydrated phase CH were calculated. It was found that these cement paste two-phase macromolecular systems predicted an isotropic material behavior. Also, these systems exhibited a high bulk modulus, compared to the elastic modulus. These results are an indication and concur with the high compression strength of cement paste seen at engineering length scale. In addition, the bulk modulus of two-phase systems consisting of hydrated CSH and unhydrated C3S or C2S was found to increase with higher levels of unhydrated components. The interaction energies of two-phase cement paste molecular structures studied in the present work were calculated, showing that a higher interaction is attained when the two phases are admixed as small components instead of cluster of phases. Finally, the mechanical behavior under shear deformation was predicted by using a quasi-static deformation method and analyzed for a representative two-phase (CSH and C2S) macromolecular structure of cement paste.

Accuracy and Precision of Three-Dimensional Low Dose CT Compared to Standard RSA in Acetabular Cups: An Experimental Study.

PubMed

Brodén, Cyrus; Olivecrona, Henrik; Maguire, Gerald Q; Noz, Marilyn E; Zeleznik, Michael P; Sköldenberg, Olof

2016-01-01

Background and Purpose. The gold standard for detection of implant wear and migration is currently radiostereometry (RSA). The purpose of this study is to compare a three-dimensional computed tomography technique (3D CT) to standard RSA as an alternative technique for measuring migration of acetabular cups in total hip arthroplasty. Materials and Methods. With tantalum beads, we marked one cemented and one uncemented cup and mounted these on a similarly marked pelvic model. A comparison was made between 3D CT and standard RSA for measuring migration. Twelve repeated stereoradiographs and CT scans with double examinations in each position and gradual migration of the implants were made. Precision and accuracy of the 3D CT were calculated. Results. The accuracy of the 3D CT ranged between 0.07 and 0.32 mm for translations and 0.21 and 0.82° for rotation. The precision ranged between 0.01 and 0.09 mm for translations and 0.06 and 0.29° for rotations, respectively. For standard RSA, the precision ranged between 0.04 and 0.09 mm for translations and 0.08 and 0.32° for rotations, respectively. There was no significant difference in precision between 3D CT and standard RSA. The effective radiation dose of the 3D CT method, comparable to RSA, was estimated to be 0.33 mSv. Interpretation. Low dose 3D CT is a comparable method to standard RSA in an experimental setting.

The efficacy of a “double-D-shaped” wire marker for radiographic measurement of acetabular cup orientation and wear

PubMed Central

Derbyshire, Brian; Raut, Videshnandan V.

2013-01-01

Historically, wire markers were attached to cemented all-plastic acetabular cups to demarcate the periphery and to measure socket wear. The wire shape was either a semi-circle passing over the pole of the cup, or a circle around the cup equator. More recently, “double-D” shaped markers were introduced with a part-circular aspect passing over the pole and a semi-circular aspect parallel to the equatorial plane. This configuration enabled cup retroversion to be distinguished from anteversion. In this study, the accuracy of radiographic measurement of cup orientation and wear was assessed for cups with “double-D” and circular markers. Each cup was attached to a measurement jig which could vary the anteversion/retroversion and internal/external rotation of the cup. A metal femoral head was fixed within the socket and radiographic images were created for all combinations of cup orientation settings. The images were measured using software with automatic edge detection, and cup orientation and zero-wear accuracies were determined for each setting. The median error for cup version measurements was similar for both types of wire marker (0.2° double-D marker, −0.24° circular marker), but measurements of the circular marker were more repeatable. The median inclination errors were 2.05° (double-D marker) and 0.23° (circular marker). The median overall “zero wear” errors were 0.19 mm (double-D marker) and 0.03 mm (circular marker). Measurements of the circular wire marker were much more repeatable. PMID:23813165

Low Frequency of Early Complications With Dual-mobility Acetabular Cups in Cementless Primary THA.

PubMed

Chughtai, Morad; Mistry, Jaydev B; Diedrich, Aloise M; Jauregui, Julio J; Elmallah, Randa K; Bonutti, Peter M; Harwin, Steven F; Malkani, Arthur L; Kolisek, Frank R; Mont, Michael A

2016-10-01

Dislocation complicates 1% to 5% of primary total hip arthroplasties (THAs). As a result, some surgeons consider dual-mobility articulations, which are usually used in the revision setting to decrease the likelihood of dislocation, as an option for primary THA. However, few studies have evaluated their use in this setting. (1) What is the cup survivorship when the dual-mobility articulation is used in the setting of primary THA? (2) What are the clinical outcomes with this approach? (3) What are the radiographic outcomes? (4) What are the complications of dual-mobility articulations in primary THA? Between 2011 and 2013, the five participating surgeons performed 495 cementless primary THAs. During that time, one of the five surgeons used dual-mobility articulations for all THAs, and the other four used it whenever the acetabular cup size was 52 mm or greater to enable a 28-mm head. Of the 495 patients, 453 (92%) were performed using this device. Smaller patients were treated with a standard THA. Of the 453 patients, a total of 43 patients (10%) were lost to followup before the 2-year minimum. The resulting 410 patients who were included in the analysis (164 men, 246 women) had a mean age of 64 years (SD, 12 years). The mean followup was 3 years (SD, 0.7 years). We performed Kaplan-Meier analyses to assess survivorship to aseptic failure and all-cause acetabular component survivorship. Clinical outcomes were evaluated using the Harris hip score (HHS); radiographs were assessed for cup migration, progressive radiolucencies, and positional changes of the components; and any surgery-related complications were recorded. The survivorship to aseptic failure and all-cause acetabular component survivorship was 99.8% (failures, n = 1) (95% confidence interval [CI], 4.517-4.547) and 99.3% (failures, aseptic, n = 1; septic, n = 2) (95% CI, 4.494-4.543); one hip had trunnion notching caused by impingement of a malpositioned cup, which was treated with revision of the cup and stem; and two patients had periprosthetic infections that were treated with two-stage revisions. There were no dislocations. Patients had a mean HHS of 94 (SD, 6) at final followup. On radiographic evaluation, no progressive radiolucencies or positional changes of the components were identified. Surgical complications included one traumatic avulsion of the abductors, one traumatic avulsion of the greater trochanter, which was repaired without revision of any of the components, and one loose femoral stem, which required revision of the femoral component only. Dual-mobility cups in primary THA yield seemingly comparable survivorship and complications to conventional THA bearings at short-term followup. Because serious complications have occasionally been reported with the use of these bearings, larger, longer term, comparative-and ideally, randomized-trials will be needed to establish the superiority of one approach over the other. Until or unless such studies show the superiority of dual-mobility designs for primary THA, we recommend that in the setting of uncomplicated primary THA, dual-mobility articulations be used only in centers that track their results carefully or in research protocols. Level IV, therapeutic study.

In vivo performance of a reduced-modulus bone cement

NASA Astrophysics Data System (ADS)

Forehand, Brett Ramsey

Total joint replacement has become one of the most common procedures in the area of orthopedics and is often the solution in patients with diseased or injured hip joints. Component loosening is a significant problem and is primarily caused by bone resorption at the bone-cement interface in cemented implants. It is our hypothesis that localized shear stresses are responsible for the resorption. It was previously shown analytically that local stresses at the interface could be reduced by using a cement of lower modulus. A new reduced modulus cement, polybutyl methylmethacrylate (PBMMA), was developed to test the hypothesis. PBMMA was formulated to exist as polybutyl methacrylate filler in a polymethyl methacrylate matrix. The success of PBMMA cement is based largely on the fact that the polybutyl component of the cement will be in the rubbery state at body temperature. In vitro characterization of the cement was undertaken previously and demonstrated a modulus of approximately one-eighth that of conventional bone cement, polymethyl methacrylate (PMMA) and increased fracture toughness. The purpose of this experiment was to perform an in vivo comparison of the two cements. A sheep model was selected. Total hip arthroplasty was performed on 50 ewes using either PBMMA or PMMA. Radiographs were taken at 6 month intervals. At one year, the contralateral femur of each sheep was implanted so that each animal served as its own control, and the animals were sacrificed. The stiffness of the bone-cement interface of the femoral component within the femur was assessed by applying a torque to the femoral component and demonstrated a significant difference in loosening between the cements when the specimens were tested in external rotation (p < 0.007). Evaluation of the mechanical data also suggests that the PBMMA sheep had a greater amount of loosening for each subject, 59% versus 4% for standard PMMA. A radiographic analysis demonstrated more signs of loosening in the PMMA series of subjects. A brief histological examination showed similar bony reaction to both cements, however, study of the interface membrane was not able to be accomplished. Reasons for the rejection of the hypothesis are discussed.

Acetabular fractures: anatomic and clinical considerations.

PubMed

Lawrence, David A; Menn, Kirsten; Baumgaertner, Michael; Haims, Andrew H

2013-09-01

Classifying acetabular fractures can be an intimidating topic. However, it is helpful to remember that there are only three basic types of acetabular fractures: column fractures, transverse fractures, and wall fractures. Within this framework, acetabular fractures are classified into two broad categories: elementary or associated fractures. We will review the osseous anatomy of the pelvis and provide systematic approaches for reviewing both radiographs and CT scans to effectively evaluate the acetabulum. Although acetabular fracture classification may seem intimidating, the descriptions and distinctions discussed and shown in this article hopefully make the topic simpler to understand. Approach the task by recalling that there are only three basic types of acetabular fractures: column fractures (coronally oriented on CT images), transverse fractures (sagittally oriented on CT images), and wall fractures (obliquely oriented on CT images). We have provided systematic approaches for reviewing both conventional radiographs and CT scans to effectively assess the acetabulum. The clinical implications of the different fracture patterns have also been reviewed because it is critically important to include pertinent information for our clinical colleagues to provide the most efficient and timely clinical care.

Fretting and Corrosion Between a Metal Shell and Metal Liner May Explain the High Rate of Failure of R3 Modular Metal-on-Metal Hips.

PubMed

Ilo, Kevin C; Derby, Emma J; Whittaker, Robert K; Blunn, Gordon W; Skinner, John A; Hart, Alister J

2017-05-01

The R3 acetabular system used with its metal liner has higher revision rates when compared to its ceramic and polyethylene liner. In June 2012, the medical and healthcare products regulatory agency issued an alert regarding the metal liner of the R3 acetabular system. Six retrieved R3 acetabular systems with metal liners underwent detailed visual analysis using macroscopic and microscopic techniques. Visual analysis discovered corrosion on the backside of the metal liners. There was a distinct border to the areas of corrosion that conformed to antirotation tab insertions on the inner surface of the acetabular shell, which are for the polyethylene liner. Scanning electron microscopy indicated evidence of crevice corrosion, and energy-dispersive X-ray analysis confirmed corrosion debris rich in titanium. The high failure rate of the metal liner option of the R3 acetabular system may be attributed to corrosion on the backside of the liner which appear to result from geometry and design characteristics of the acetabular shell. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of acetabular reinforcement ring with hook for acetabular dysplasia clarified by three-dimensional finite element analysis.

PubMed

Zhao, Xin; Chosa, Etsuo; Yamako, Go; Watanabe, Shinji; Deng, Gang; Totoribe, Koji

2013-12-01

The objective of this study was to biomechanically determine the effect of the severity of acetabular dysplasia, number and positions of screws and type of bone graft material used on the initial fixation strength of the acetabular reinforcement ring with hook (Ganz ring) using the finite element method. Relative micromotion increased as the severity of acetabular dysplasia increased and tended to decrease as the number of screws increased, but varied according to screw placement position. Increased strength of the bone graft material led to decreased relative micromotion. Biomechanically, the Ganz ring can be placed securely using 3 screws in patients with Crowe 1 dysplasia. However, in patients with Crowe 2 or higher dysplasia, it is necessary to spread at least 4 screws across an area of good host bone. © 2013.

Spine–hip relations in patients with hip osteoarthritis

PubMed Central

Rivière, Charles; Lazic, Stefan; Dagneaux, Louis; Van Der Straeten, Catherine; Cobb, Justin; Muirhead-Allwood, Sarah

2018-01-01

Patients with hip osteoarthritis often have an abnormal spine-hip relation (SHR), meaning the presence of a clinically deleterious spine-hip and/or hip-spine syndrome. Definition of the individual SHR is ideally done using the EOS® imaging system or, if not available, with conventional lumbopelvic lateral radiographs. By pre-operatively screening patients with abnormal SHR, it is possible to refine total hip replacement (THR) surgical planning, which may improve outcomes. An important component of the concept of kinematically aligned total hip arthroplasty (KA THA) consists of defining the optimal acetabular cup design and orientation based on the assessment of an individual’s SHR, and use of the transverse acetabular ligament to adjust the cup positioning. The Bordeaux classification might advance the understanding of SHR and hopefully help improve THR outcomes. Cite this article: EFORT Open Rev 2018;3:39-44. DOI: 10.1302/2058-5241.3.170020 PMID:29657844

Radiographic parameters associated with pain following total hip and surface arthroplasty.

PubMed

Nam, Denis; Sauber, Timothy J; Barrack, Toby; Johnson, Staci R; Brooks, Peter J; Nunley, Ryan M

2015-03-01

Pain following total hip arthroplasty (THA) and surface arthroplasty (SRA) remains a significant source of patient dissatisfaction. Two hundred twenty-four SRA and 196 THA patients completed a pain drawing questionnaire and postoperative radiographic measurements of component positioning were performed. In the SRA cohort, 11 of 21 patients (52%) with acetabular uncoverage of ≥5 mm versus 43 of 147 (29%) with acetabular uncoverage of ≤4.9 mm reported groin pain (P=.03). In the THA cohort, an increased distal-third canal fill ratio and a lower canal calcar ratio trended towards a higher incidence of thigh pain (P=.10 and .06), while a decreased mid-third canal fill ratio was associated with increased severity of thigh pain (P=.04). This study identifies associations between radiographic findings and pain following THA and SRA. Copyright © 2014 Elsevier Inc. All rights reserved.

[Pelvic reconstructions after bone tumor resection].

PubMed

Anract, Philippe; Biau, David; Babinet, Antoine; Tomeno, Bernard

2014-02-01

The three more frequent primitive malignant bone tumour which concerned the iliac bone are chondrosarcoma, following Ewing sarcoma and osteosarcoma. Wide resection remains the most important part of the treatment associated with chemotherapy for osteosarcoma and the Ewing sarcoma. Iliac wing resections and obdurate ring don't required reconstruction. However, acetabular resections and iliac wing resection with disruption of the pelvic ring required reconstruction to provide acceptable functional result. Acetabular reconstruction remains high technical demanding challenge. After isolated acetabular resection or associated to obdurate ring, our usual method of reconstruction is homolateral proximal femoral autograft and total hip prosthesis but it is possible to also used : saddle prosthesis, Mac Minn prosthesis with auto or allograft, modular prosthesis or custom made prosthesis, massive allograft with or without prosthesis and femoro-ilac arthrodesis. After resection of the iliac wing plus acetabulum, reconstruction can be performed by femoro-obturatrice and femora-sacral arthrodesis, homolateral proximal femoral autograft and prosthesis, femoral medialisation, massive allograft and massive allograft. Carcinological results are lesser than resection for distal limb tumor, local recurrence rate range 17 to 45%. Functional results after Iliac wing and obdurate ring are good. However, acetabular reconstruction provide uncertain functional results. The lesser results arrive after hemipelvic or acetabular and iliac wing resection-reconstruction, especially when gluteus muscles were also resected. The most favourable results arrive after isolated acetabular or acetabular plus obturateur ring resection-reconstruction.

A novel electromagnetic navigation tool for acetabular surgery.

PubMed

Lehmann, Wolfgang; Rueger, Johannes M; Nuechtern, Jakob; Grossterlinden, Lars; Kammal, Michael; Hoffmann, Michael

2015-10-01

Acetabular fracture surgery is demanding and screw placement along narrow bony corridors remains challenging. It necessitates x-ray radiation for fluoroscopically assisted screw insertion. The purpose of this cadaver study was to evaluate the feasibility, accuracy and operation time of a novel electromagnetic navigation system for screw insertion along predefined acetabular corridors. A controlled laboratory study with a total of 24 electromagnetically navigated screw insertions was performed on 8 cadaveric acetabula. 3 peri-acetabular bony corridors (QSS, Quadrilateral Surface Screw; IAS, Infra-Acetabular Screw; PCS, Posterior Column Screw) were defined and screws were placed in a defined order without fluoroscopy. Operation time was documented. Postoperative CT scans were performed to analyse accuracy of screw placement. Mean cadaver age was 70.4 ± 11.7. Successful screw placement was accomplished in 22 out of 24 (91.7%) cases. The overall mean time for all 3 acetabular screws was 576.6 ± 75.9s. All 3 complications occurred during the placement of the IAS due to an impassable narrow bony corridor. QSS mean length was 50 ± 5mm, IAS mean length was 85 ± 10mm and PCS mean length was 120 ± 5mm. In this cadaver study the novel electromagnetic navigation system was feasible to allow accurate screw placement without fluoroscopy in defined narrow peri-acetabular bony corridors. Copyright © 2015 Elsevier Ltd. All rights reserved.

What Is the Rerevision Rate After Revising a Hip Resurfacing Arthroplasty? Analysis From the AOANJRR.

PubMed

Wong, James Min-Leong; Liu, Yen-Liang; Graves, Stephen; de Steiger, Richard

2015-11-01

More than 15,000 primary hip resurfacing arthroplasties have been recorded by the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) with 884 primary procedures requiring revision for reasons other than infection, a cumulative percent revision rate at 12 years of 11%. However, few studies have reported the survivorship of these revision procedures. (1) What is the cumulative percent rerevision rate for revision procedures for failed hip resurfacings? (2) Is there a difference in rerevision rate among different types of revision or bearing surfaces? The AOANJRR collects data on all primary and revision hip joint arthroplasties performed in Australia and after verification against health department data, checking of unmatched procedures, and subsequent retrieval of unreported procedures is able to obtain an almost complete data set relating to hip arthroplasty in Australia. Revision procedures are linked to the known primary hip arthroplasty. There were 15,360 primary resurfacing hip arthroplasties recorded of which 884 had undergone revision and this was the cohort available to study. The types of revisions were acetabular only, femoral only, or revision of both acetabular and femoral components. With the exception of the acetabular-only revisions, all revisions converted hip resurfacing arthroplasties to conventional (stemmed) total hip arthroplasties (THAs). All initial revisions for infection were excluded. The survivorship of the different types of revisions and that of the different bearing surfaces used were estimated using the Kaplan-Meier method and compared using Cox proportional hazard models. Cumulative percent revision was calculated by determining the complement of the Kaplan-Meier survivorship function at that time multiplied by 100. Of the 884 revisions recorded, 102 underwent further revision, a cumulative percent rerevision at 10 years of 26% (95% confidence interval, 19.6-33.5). There was no difference in the rate of rerevision between acetabular revision and combined femoral and acetabular revision (hazard ratio [HR], 1.06 [0.47-2], p = 0.888), femoral revision and combined femoral and acetabular revision (HR, 1.00 [0.65-2], p = 0.987), and acetabular revision and femoral revision (HR, 1.06 [0.47-2], p = 0.893). There was no difference in the rate of rerevision when comparing different bearing surfaces (metal-on-metal versus ceramic-on-ceramic HR, 0.46 [0.16-1.29], p = 0.141; metal-on-metal versus ceramic-on-crosslinked polyethylene HR, 0.51 [0.15-1.76], p = 0.285; metal-on-metal versus metal-on-crosslinked polyethylene HR, 0.62 [0.20-1.89], p = 0.399; and metal-on-metal versus oxinium-on-crosslinked polyethylene HR, 0.53 [0.14-2.05], p = 0.356). Revision of a primary hip resurfacing arthroplasty is associated with a high risk of rerevision. This study may help surgeons guide their patients about the outcomes in the longer term after the first revision of hip resurfacing arthroplasty. Level III, therapeutic study.

[Contact characteristics research of acetabular weight-bearing area with different internal fixation methods after compression fracture of acetabular dome].

PubMed

Xu, Bowen; Zhang, Qingsong; An, Siqi; Pei, Baorui; Wu, Xiaobo

2017-08-01

To establish the model of compression fracture of acetabular dome, and to measure the contact characteristics of acetabular weight-bearing area of acetabulum after 3 kinds of internal fixation. Sixteen fresh adult half pelvis specimens were randomly divided into 4 groups, 4 specimens each group. Group D was the complete acetabulum (control group), and the remaining 3 groups were prepared acetabular dome compression fracture model. The fractures were fixed with reconstruction plate in group A, antegrade raft screws in group B, and retrograde raft screws in group C. The pressure sensitive films were attached to the femoral head, and the axial compression test was carried out on the inverted single leg standing position. The weight-bearing area, average stress, and peak stress were measured in each group. Under the loading of 500 N, the acetabular weight-bearing area was significantly higher in group D than in other 3 groups ( P <0.05), and the average stress and peak stress were significantly lower than in other 3 groups ( P <0.05). The acetabular weight-bearing area were significantly higher in group B and group C than in group A, and the average stress and peak stress were significantly lower than in group A ( P <0.05). There was no significant difference in the above indexes between group B and group C ( P >0.05). For the compression fracture of the acetabular dome, the contact characteristics of the weight-bearing area can not restore to the normal level, even if the anatomical reduction and rigid internal fixation were performed; compared with the reconstruction plate fixation, antegrade and retrograde raft screws fixations can increase the weight-bearing area, reduce the average stress and peak stress, and reduce the incidence of traumatic arthritis.

/sup 99m/Tc-methylene diphosphonate bone imaging in the evaluation of total hip prostheses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiss, P.E.; Mall, J.C.; Hoffer, P.B.

1979-12-01

A retrospective study was performed to determine the accuracy of /sup 99m/Tc-methylene diphosphonate bone imaging in the evaluation of total hip arthroplasty for loosening and/or infection. Using focally increased activity at the tip of the femoral component or in the region of the acetabular component as a criterion, the examination was 77% specific and 100% sensitive for loosening and/or infection. A possible explanation for the increased uptake at the tip of the femoral component and the role of this examination in the management of a painful total hip prosthesis are discussed.

Dissociation of modular total hip arthroplasty at the neck-stem interface without dislocation.

PubMed

Kouzelis, A; Georgiou, C S; Megas, P

2012-12-01

Modular femoral and acetabular components are now widely used, but only a few complications related to the modularity itself have been reported. We describe a case of dissociation of the modular total hip arthroplasty (THA) at the femoral neck-stem interface during walking. The possible causes of this dissociation are discussed. Successful treatment was provided with surgical revision and replacement of the modular neck components. Surgeons who use modular components in hip arthroplasties should be aware of possible early complications in which the modularity of the prostheses is the major factor of failure.

Cup-cage construct for acute fractures of the acetabulum, re-defining indications.

PubMed

Chana-Rodríguez, Francisco; Villanueva-Martínez, Manuel; Rojo-Manaute, Jose; Sanz-Ruíz, Pablo; Vaquero-Martín, Javier

2012-12-01

Acetabular fractures in the elderly are challenging injuries. The use of a trabecular metal acetabular cage was investigated as the treatment option in a series of elderly patients with acetabular fractures. At a 2-year follow up, 6 elderly patients were found to have mimimum pain, increased function, and increased scores using the Merle d'Aubigné and Postel system modified by Charnley. Radiographically, the areas of morsellised autograft that surrounded the cups were seen to have incorporated uniformly well, and the acetabular fractures were healed within six months after surgery. No mechanical failure, screw breakage, loosening, or migration was noticed. This novel indication of the cup-cage construction that uses revision techniques, for selected patients and fractures, to achieve an acute stable reconstruction, should be considered as an alternative reconstruction option in elderly patients presenting with acetabular fractures. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Bimetric cementless total hip replacement: 7-18 year follow-up assessing the influence of acetabular design on survivorship.

PubMed

Russell, R C; Ghassemi, A; Dorrell, J H; Powles, D P

2009-08-01

The purpose of this study was to evaluate the mid- to long-term survivorship of Bimetric cementless total hip replacement and assess how it is affected by the acetabular design. This was a retrospective analysis of 127 Bimetric cementless total hip replacements in 110 patients with a follow-up of 7-18 years. A single design stem and three different cementless metal-backed acetabular designs were used. Patients were assessed clinically using the Harris hip score and radiologically by independent review of current hip radiographs. There was only one case of aseptic loosening of the femoral stem. The earliest acetabular design showed a high failure rate whilst the latter two designs showed a 96% survivorship at a mean of 9.5 years. We conclude that a combination of the bimetric stem with either of the latter acetabular cup designs has a good mid- to long-term performance.

Total hip arthroplasty of dysplastic hip after previous Chiari pelvic osteotomy.

PubMed

Minoda, Yukihide; Kadowaki, Toru; Kim, Mitsunari

2006-08-01

Many reports have suggested that Chiari pelvic osteotomy would improve the results of acetabular component placement and fixation in subsequent total hip arthroplasty. However, little is known concerning the biomechanical, radiological, and clinical effects of Chiari pelvic osteotomy on subsequent total hip arthroplasty. Ten total hip arthroplasties for developmental dysplasia of the hip after previous Chiari pelvic osteotomy (Chiari group) were compared with 20 total hip arthroplasties for developmental dysplasia of the hip without previous surgery (control group). Preoperative patient demographic data and operative technique were well matched between the groups. The mean duration of follow-up was 3.0 years. Biomechanical, radiological, and clinical evaluations were performed. No acetabular or femoral components exhibited loosening. All patients had good or excellent clinical score according to the Merle d'Aubigne-Postel rating system at the most recent follow-up. Abductor force and joint force were smaller in the Chiari group, although long operative time, more blood loss, and verticalization of joint force were noted in this group. This limited study suggested that Chiari pelvic osteotomy changed the biomechanical features of the hip joint, and that this alteration might have compromised subsequent total hip arthroplasty.

A patterned microtexture to reduce friction and increase longevity of prosthetic hip joints

PubMed Central

Chyr, Anthony; Qiu, Mingfeng; Speltz, Jared; Jacobsen, Ronald L.; Sanders, Anthony P.; Raeymaekers, Bart

2014-01-01

More than 285,000 total hip replacement surgeries are performed in the US each year. Most prosthetic hip joints consist of a cobalt-chromium (CoCr) femoral head that articulates with a polyethylene acetabular component, lubricated with synovial fluid. The statistical survivorship of these metal-on-polyethylene prosthetic hip joints declines significantly after 10 to 15 years of use, primarily as a result of polyethylene wear and wear debris incited disease. The current engineering paradigm to increase the longevity of prosthetic hip joints is to improve the mechanical properties of the polyethylene component, and to manufacture ultra-smooth articulating surfaces. In contrast, we show that adding a patterned microtexture to the ultra-smooth CoCr femoral head reduces friction when articulating with the polyethylene acetabular liner. The microtexture increases the load-carrying capacity and the thickness of the joint lubricant film, which reduces contact between the articulating surfaces. As a result, friction and wear is reduced. We have used a lubrication model to design the geometry of the patterned microtexture, and experimentally demonstrate reduced friction for the microtextured compared to conventional smooth surrogate prosthetic hip joints. PMID:25013240

Comparison of cemented and uncemented fixation in total knee arthroplasty.

PubMed

Brown, Thomas E; Harper, Benjamin L; Bjorgul, Kristian

2013-05-01

As a result of reading this article, physicians should be able to :1. Understand the rationale behind using uncemented fixation in total knee arthroplasty.2.Discuss the current literature comparing cemented and uncemented total knee arthroplasty3. Describe the value of radiostereographic analysis in assessing implant stability.4. Appreciate the limitations in the available literature advocating 1 mode of fixation in total knee arthroplasty. Total knee arthroplasty performed worldwide uses either cemented, cementless, or hybrid (cementless femur with a cemented tibia) fixation of the components. No recent literature review concerning the outcomes of cemented vs noncemented components has been performed. Noncemented components offer the potential advantage of a biologic interface between the bone and implants, which could demonstrate the greatest advantage in long-term durable fixation in the follow-up of young patients undergoing arthroplasty. Several advances have been made in the backing of the tibial components that have not been available long enough to yield long-term comparative follow-up studies. Short-term radiostereographic analysis studies have yielded differing results. Although long-term, high-quality studies are still needed, material advances in biologic fixation surfaces, such as trabecular metal and hydroxyapatite, may offer promising results for young and active patients undergoing total knee arthroplasty when compared with traditional cemented options. Copyright 2013, SLACK Incorporated.

Pelvic incidence: a predictive factor for three-dimensional acetabular orientation-a preliminary study.

PubMed

Boulay, Christophe; Bollini, Gérard; Legaye, Jean; Tardieu, Christine; Prat-Pradal, Dominique; Chabrol, Brigitte; Jouve, Jean-Luc; Duval-Beaupère, Ginette; Pélissier, Jacques

2014-01-01

Acetabular cup orientation (inclination and anteversion) is a fundamental topic in orthopaedics and depends on pelvis tilt (positional parameter) emphasising the notion of a safe range of pelvis tilt. The hypothesis was that pelvic incidence (morphologic parameter) could yield a more accurate and reliable assessment than pelvis tilt. The aim was to find out a predictive equation of acetabular 3D orientation parameters which were determined by pelvic incidence to include in the model. The second aim was to consider the asymmetry between the right and left acetabulae. Twelve pelvic anatomic specimens were measured with an electromagnetic Fastrak system (Polhemus Society) providing 3D position of anatomical landmarks to allow measurement of acetabular and pelvic parameters. Acetabulum and pelvis data were correlated by a Spearman matrix. A robust linear regression analysis provided prediction of acetabulum axes. The orientation of each acetabulum could be predicted by the incidence. The incidence is correlated with the morphology of acetabula. The asymmetry of the acetabular roof was correlated with pelvic incidence. This study allowed analysis of relationships of acetabular orientation and pelvic incidence. Pelvic incidence (morphologic parameter) could determine the safe range of pelvis tilt (positional parameter) for an individual and not a group.

Pelvic Incidence: A Predictive Factor for Three-Dimensional Acetabular Orientation—A Preliminary Study

PubMed Central

Bollini, Gérard; Legaye, Jean; Tardieu, Christine; Prat-Pradal, Dominique; Chabrol, Brigitte; Jouve, Jean-Luc; Duval-Beaupère, Ginette; Pélissier, Jacques

2014-01-01

Acetabular cup orientation (inclination and anteversion) is a fundamental topic in orthopaedics and depends on pelvis tilt (positional parameter) emphasising the notion of a safe range of pelvis tilt. The hypothesis was that pelvic incidence (morphologic parameter) could yield a more accurate and reliable assessment than pelvis tilt. The aim was to find out a predictive equation of acetabular 3D orientation parameters which were determined by pelvic incidence to include in the model. The second aim was to consider the asymmetry between the right and left acetabulae. Twelve pelvic anatomic specimens were measured with an electromagnetic Fastrak system (Polhemus Society) providing 3D position of anatomical landmarks to allow measurement of acetabular and pelvic parameters. Acetabulum and pelvis data were correlated by a Spearman matrix. A robust linear regression analysis provided prediction of acetabulum axes. The orientation of each acetabulum could be predicted by the incidence. The incidence is correlated with the morphology of acetabula. The asymmetry of the acetabular roof was correlated with pelvic incidence. This study allowed analysis of relationships of acetabular orientation and pelvic incidence. Pelvic incidence (morphologic parameter) could determine the safe range of pelvis tilt (positional parameter) for an individual and not a group. PMID:25006461

Effect of bioglass 45S5 addition on properties, microstructure and cellular response of tetracalcium phosphate/monetite cements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stulajterova, R., E-mail: rstulajterova@saske.sk

Tetracalcium phosphate/nanomonetite (TTCPMH) cement composites with 7.5 and 15 wt% addition of melt-derived 45S5 bioactive glass were prepared by mechanical homogenization of powder components and 2% NaH{sub 2}PO{sub 4} solution was used as a hardening liquid. The properties of composites with the acidic (Ca/P ratio equal 1.5) or basic (Ca/P ratio equal 1.67) TTCPMH component were compared. Addition of glass component caused rapid rise in pH of composites up to 10. In microstructure of basic cement composite, the large bioglass particles weakly bounded to surrounding cement matrix were found contrary to a more compact microstructure of acidic cement composites withmore » the high number of spherical silica particles. Both the significant refinement of hydroxyapatite particles and the change to needle-like morphology with rise in the content of bioglass were identified in hydroxyapatite coatings created during soaking of composites in phosphate buffered saline. In acidic cement mixtures, the increase of compressive strength with an amount of bioglass was found whereas the opposite tendency was revealed in the case of basic cement mixtures. The higher concentrations of ions were verified in solutions after immersion of acidic cement composites. The severe cytotoxicity of extracts and composite cement substrates containing 15 wt% of bioglass demonstrated adverse effects of both the ionic concentrations and unappropriate surface texture on proliferation of mesenchymal stem cells. The enhanced ALP activities of cells cultured on composite cements confirmed the positive effect of bioactive glass addition on differentiation of mesenchymal stem cells. - Highlights: • Novel B45S5 bioglass/tetracalcium phosphate/nanomonetite cement composites • Cement basicity negatively affected their microstructure. • Acid composite cements had higher compressive strengths than basic composites. • Fast differentiation of MSC to osteoblast line on composite with 7.5 wt% of bioglass • Severe cytotoxicity of 24 h extracts from composites with 15 wt% of bioglass.« less

Press-fit acetabular cup fixation: principles and testing.

PubMed

Macdonald, W; Carlsson, L V; Charnley, G J; Jacobsson, C M

1999-01-01

Pre-clinical testing of the fixation of press-fit acetabular components of total hip prostheses relies on cadaver or synthetic bone, but the properties and geometry of bone models differ from those of physiological bone. Cup designs use varied mechanisms for initial stability in bone; therefore, using different analogues and tests is appropriate. Press-fit cup stability was tested in the following: firstly, polyurethane (PU) foam modelling cancellous support; secondly, glass-fibre reinforced epoxide (GFRE) tubes modelling acetabular cortical support; thirdly, cadaveric acetabula. Three commercial cups [Harris-Galante II (H-G-II), Zimmer; Optifix, Smith & Nephew, Richards; porous coated anatomic (PCA), Howmedica] and an experimental cup with enhanced rim fixation were tested in three modes: direct pull-out, lever-out and axial torque. The fixation stabilities measured in the PU and the GFRE models showed trends consistent with those in cadaver bone, differing in the oversizing and cup geometry. The experimental cup was significantly more secure in most modes than other cups; the H-G II and Optifix cups showed similar stabilities, lower than that of the experimental cup but greater than that of the PCA cup (analysis of variance and Tukey's highly significant test; p < 0.001). The stabilities measured in cadaver bone more closely approximated those in GFRE. The use of several bone analogues enables separation of fixation mechanisms, allowing more accurate prediction of in vivo performance.

Accelerated aging, natural aging, and small punch testing of gamma-air sterilized polycarbonate urethane acetabular components.

PubMed

Kurtz, S M; Siskey, R; Reitman, M

2010-05-01

The objectives of this study were three-fold: (1) to determine the applicability of the small punch test to characterize Bionate 80A polycarbonate urethane (PCU) acetabular implants; (2) to evaluate the susceptibility of PCU acetabular implants to exhibit degradation of mechanical behavior following gamma irradiation in air and accelerated aging; and (3) to compare the oxidation of gamma-air sterilized PCU following accelerated aging and 5 years of natural shelf aging. In addition to attenuated total reflectance-Fourier transform infrared spectroscopy, we also adapted a miniature specimen mechanical test, the small punch test, for the deformable PCU cups. Accelerated aging was performed using ASTM F2003, a standard test that represents a severe oxidative challenge. The results of this study suggest that the small punch test is sufficiently sensitive and reproducible to discriminate slight differences in the large-deformation mechanical behavior of Bionate 80A following accelerated aging. The gamma-air sterilized PCU had a reduction of 9% in ultimate load after aging. Five years of shelf aging had little effect on the mechanical properties of the PCU. Overall, our findings suggest that the Bionate 80A material has greater oxidative stability than ultra-high molecular weight polyethylene following gamma irradiation in air and exposure to a severe oxidative challenge. (c) 2010 Wiley Periodicals, Inc.

Acetabular cartilage defects cause altered hip and knee joint coordination variability during gait.

PubMed

Samaan, Michael A; Teng, Hsiang-Ling; Kumar, Deepak; Lee, Sonia; Link, Thomas M; Majumdar, Sharmila; Souza, Richard B

2015-12-01

Patients with acetabular cartilage defects reported increased pain and disability compared to those without acetabular cartilage defects. The specific effects of acetabular cartilage defects on lower extremity coordination patterns are unclear. The purpose of this study was to determine hip and knee joint coordination variability during gait in those with and without acetabular cartilage defects. A combined approach, consisting of a semi-quantitative MRI-based quantification method and vector coding, was used to assess hip and knee joint coordination variability during gait in those with and without acetabular cartilage lesions. The coordination variability of the hip flexion-extension/knee rotation, hip abduction-adduction/knee rotation, and hip rotation/knee rotation joint couplings were reduced in the acetabular lesion group compared to the control group during loading response of the gait cycle. The lesion group demonstrated increased variability in the hip flexion-extension/knee rotation and hip abduction-adduction/knee rotation joint couplings, compared to the control group, during the terminal stance/pre-swing phase of gait. Reduced variability during loading response in the lesion group may suggest reduced movement strategies and a possible compensation mechanism for lower extremity instability during this phase of the gait cycle. During terminal stance/pre-swing, a larger variability in the lesion group may suggest increased movement strategies and represent a compensation or pain avoidance mechanism caused by the load applied to the hip joint. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of temporary cement contamination on the surface free energy and dentine bond strength of self-adhesive cements.

PubMed

Takimoto, Masayuki; Ishii, Ryo; Iino, Masayoshi; Shimizu, Yusuke; Tsujimoto, Akimasa; Takamizawa, Toshiki; Ando, Susumu; Miyazaki, Masashi

2012-02-01

The surface free energy and dentine bond strength of self-adhesive cements were examined after the removal of temporary cements. The labial dentine surfaces of bovine mandibular incisors were wet ground with #600-grit SiC paper. Acrylic resin blocks were luted to the prepared dentine surfaces using HY Bond Temporary Cement Hard (HY), IP Temp Cement (IP), Fuji TEMP (FT) or Freegenol Temporary Cement (TC), and stored for 1 week. After removal of the temporary cements with an ultrasonic tip, the contact angle values of five specimens per test group were determined for the three test liquids, and the surface-energy parameters of the dentine surfaces were calculated. The dentine bond strengths of the self-adhesive cements were measured after removal of the temporary cements in a shear mode at a crosshead speed of 1.0mm/min. The data were subjected to one-way analysis of variance (ANOVA) followed by Tukey's HSD test. For all surfaces, the value of the estimated surface tension component γ(S)(d) (dispersion) was relatively constant at 41.7-43.3 mJm(-2). After removal of the temporary cements, the value of the γ(S)(h) (hydrogen-bonding) component decreased, particularly with FT and TC. The dentine bond strength of the self-adhesive cements was significantly higher for those without temporary cement contamination (8.2-10.6 MPa) than for those with temporary cement contamination (4.3-7.1 MPa). The γ(S) values decreased due to the decrease of γ(S)(h) values for the temporary cement-contaminated dentine. Contamination with temporary cements led to lower dentine bond strength. The presence of temporary cement interferes with the bonding performance of self-adhesive cements to dentine. Care should be taken in the methods of removal of temporary cement when using self-adhesive cements. Copyright © 2011 Elsevier Ltd. All rights reserved.

The Bimetric cementless total hip replacement: 7–18 year follow-up assessing the influence of acetabular design on survivorship

PubMed Central

Ghassemi, A.; Dorrell, J. H.; Powles, D. P.

2008-01-01

The purpose of this study was to evaluate the mid- to long-term survivorship of Bimetric cementless total hip replacement and assess how it is affected by the acetabular design. This was a retrospective analysis of 127 Bimetric cementless total hip replacements in 110 patients with a follow-up of 7–18 years. A single design stem and three different cementless metal-backed acetabular designs were used. Patients were assessed clinically using the Harris hip score and radiologically by independent review of current hip radiographs. There was only one case of aseptic loosening of the femoral stem. The earliest acetabular design showed a high failure rate whilst the latter two designs showed a 96% survivorship at a mean of 9.5 years. We conclude that a combination of the bimetric stem with either of the latter acetabular cup designs has a good mid- to long-term performance. PMID:18551293

Nonsurgical Treatment of Acetabular Labral Tears.

PubMed

Theige, Melissa; David, Shannon

2018-05-04

Clinical Scenario: Surgical treatment of acetabular labral tears has been explored in multiple studies, while there is a lack of research on the effectiveness of conservative methods. Focused Clinical Question: To what extent can nonsurgical treatment produce symptomatic or functional improvements in athletes with an acetabular labral tear? Summary of Search, Best Evidence Appraised, and Key Findings: The literature was searched for studies of patients with confirmed acetabular labral tears who participated in any level of sport. Four studies were located, all of which were included. Clinical Bottom Line: The research discussed in this review agreed that conservative management of acetabular labral tears produced measurable improvements in pain and function among the athletes studied, including their ability to participate in sport activities. Based on these findings, it appears that conservative management is effective at rehabilitating athletes with acetabular labral tears. However, this method should not be applied to every athlete based on the low strength of current research. Treatment plans should be decided upon on a case-by-case basis. Strength of Recommendation: The studies located were of low quality. The highest Oxford Center for Evidence-Based Medicine Level of Evidence achieved was 4. Higher level studies must be conducted before the conclusions of this research can be applied clinically with assertion. Strength of recommendation is level 3.

Intraoperative CT in the assessment of posterior wall acetabular fracture stability.

PubMed

Cunningham, Brian; Jackson, Kelly; Ortega, Gil

2014-04-01

Posterior wall acetabular fractures that involve 10% to 40% of the posterior wall may or may not require an open reduction and internal fixation. Dynamic stress examination of the acetabular fracture under fluoroscopy has been used as an intraoperative method to assess joint stability. The aim of this study was to demonstrate the value of intraoperative ISO computed tomography (CT) examination using the Siemens ISO-C imaging system (Siemens Corp, Malvern, Pennsylvania) in the assessment of posterior wall acetabular fracture stability during stress examination under anesthesia. In 5 posterior wall acetabular fractures, standard fluoroscopic images (including anteroposterior pelvis and Judet radiographs) with dynamic stress examinations were compared with the ISO-C CT imaging system to assess posterior wall fracture stability during stress examination. After review of standard intraoperative fluoroscopic images under dynamic stress examination, all 5 cases appeared to demonstrate posterior wall stability; however, when the intraoperative images from the ISO-C CT imaging system demonstrated that 1 case showed fracture instability of the posterior wall segment during stress examination, open reduction and internal fixation was performed. The use of intraoperative ISO CT imaging has shown an initial improvement in the surgeon's ability to assess the intraoperative stability of posterior wall acetabular fractures during stress examination when compared with standard fluoroscopic images. Copyright 2014, SLACK Incorporated.

A Pilot Study of Augmented Reality Technology Applied to the Acetabular Cup Placement During Total Hip Arthroplasty.

PubMed

Ogawa, Hiroyuki; Hasegawa, Seiichirou; Tsukada, Sachiyuki; Matsubara, Masaaki

2018-06-01

We developed an acetabular cup placement device, the AR-HIP system, using augmented reality (AR). The AR-HIP system allows the surgeon to view an acetabular cup image superimposed in the surgical field through a smartphone. The smartphone also shows the placement angle of the acetabular cup. This preliminary study was performed to assess the accuracy of the AR-HIP system for acetabular cup placement during total hip arthroplasty (THA). We prospectively measured the placement angles using both a goniometer and AR-HIP system in 56 hips of 54 patients undergoing primary THA. We randomly determined the order of intraoperative measurement using the 2 devices. At 3 months after THA, the placement angle of the acetabular cup was measured on computed tomography images. The primary outcome was the absolute value of the difference between intraoperative and postoperative computed tomography measurements. The measurement angle using AR-HIP was significantly more accurate in terms of radiographic anteversion than that using a goniometer (2.7° vs 6.8°, respectively; mean difference 4.1°; 95% confidence interval, 3.0-5.2; P < .0001). There was no statistically significant difference in terms of radiographic inclination (2.1° vs 2.6°; mean difference 0.5°; 95% confidence interval, -1.1 to 0.1; P = .13). In this pilot study, the AR-HIP system provided more accurate information regarding acetabular cup placement angle than the conventional method. Further studies are required to confirm the utility of the AR-HIP system as a navigation tool. Copyright © 2018 Elsevier Inc. All rights reserved.

Does the optimal position of the acetabular fragment should be within the radiological normal range for all developmental dysplasia of the hip? A patient-specific finite element analysis.

PubMed

Wang, Xuyi; Peng, Jianping; Li, De; Zhang, Linlin; Wang, Hui; Jiang, Leisheng; Chen, Xiaodong

2016-10-04

The success of Bernese periacetabular osteotomy depends significantly on how extent the acetabular fragment can be corrected to its optimal position. This study was undertaken to investigate whether correcting the acetabular fragment into the so-called radiological "normal" range is the best choice for all developmental dysplasia of the hip with different severities of dysplasia from the biomechanical view? If not, is there any correlation between the biomechanically optimal position of the acetabular fragment and the severity of dysplasia? Four finite element models with different severities of dysplasia were developed. The virtual periacetabular osteotomy was performed with the acetabular fragment rotated anterolaterally to incremental center-edge angles; then, the contact area and pressure and von Mises stress in the cartilage were calculated at different correction angles. The optimal position of the acetabular fragment for patients 1, 2, and 3 was when the acetabular fragment rotated 17° laterally (with the lateral center-edge angle of 36° and anterior center-edge angle of 58°; both were slightly larger than the "normal" range), 25° laterally following further 5° anterior rotation (with the lateral center-edge angle of 31° and anterior center-edge angle of 51°; both were within the "normal" range), and 30° laterally following further 10° anterior rotation (with the lateral center-edge angle of 25° and anterior center-edge angle of 40°; both were less than the "normal" range), respectively. The optimal corrective position of the acetabular fragment is severity dependent rather than within the radiological "normal" range for developmental dysplasia of the hip. We prudently proposed that the optimal correction center-edge angle of mild, moderate, and severe developmental dysplasia of the hip is slightly larger than the "normal" range, within the "normal" range, and less than the lower limit of the "normal" range, respectively.

Evora® chromium-cobalt dual mobility socket: results at a minimum 10 years' follow-up.

PubMed

Leclercq, S; Benoit, J Y; de Rosa, J P; Tallier, E; Leteurtre, C; Girardin, P H

2013-12-01

The Evora chromium-cobalt alloy dual mobility socket claims to display a large articulation tribology different from that of stainless steel models, limiting the risk of intraprosthetic dislocation and wear. The present study reports a minimum of 10years' follow-up in a multicenter prospective series of 200 sockets previously reported on at 5years. The use of chromium-cobalt in dual mobility sockets provides a low rate of failure at 10years, especially as regards to osteolysis and intraprosthetic dislocation. Two hundred hydroxyapatite-coated molded chromium-cobalt sockets without titanium interface were implanted without cement in 194 patients with a mean age of 70 years (range, 32-91 years). Clinical results were assessed on Postel Merle d'Aubigné and Harris scores, plain radiographs and survival analysis. At a mean 11 years' follow-up (10-13 years), 56 patients had died and 31 were lost to follow-up. Four underwent surgical revision (3 femoral components, and 1 socket for migration at 9 years with complete disappearance of the hydroxyapatite). A total of 109 implants were analyzable in 107 patients with a mean age of 81 years (55-93 years). At follow-up, the mean Harris score was 90 (75-96) and the PMA score 16.3 (14-18). There were no cases of loosening (except for the case reoperated on at 9 years) and no acetabular radiolucency or cysts. There were 2 cases of non-evolutive femoral radiolucency and 10 of femoral granuloma, involving head size > 22 mm (P<0.0001) and a cemented titanium stem (P=0.004) as risk factors. There were no dislocations in the large or small articulation. Ten-year survival was 99% (95% CI: 97.3%-100%) with socket revision as censorship criterion. The absence of dislocation in both small and large articulations confirmed the efficacy of the dual mobility concept and suggested an advantage for chromium-cobalt sockets in reducing the rate of intraprosthetic dislocation and preventing blockage of the large articulation by a better performance in the friction couple. Granulomas were associated with wear in cemented titanium stems and with heads greater than 22 mm in diameter. Ten-year survival was 99% (censorship criterion: revision for socket failure); there was, however, one case of socket loosening with disappearance of the hydroxyapatite, indicating that surveillance should be continued in this cohort. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Safe surgical technique for associated acetabular fractures

PubMed Central

2013-01-01

Associated acetabular fractures are challenging injuries to manage. The complex surgical approaches and the technical difficulty in achieving anatomical reduction imply that the learning curve to achieve high-quality care of patients with such challenging injuries is extremely steep. This first article in the Journal’s “Safe Surgical Technique” section presents the standard surgical care, in conjunction with intraoperative tips and tricks, for the safe management of all subgroups of associated acetabular fractures. PMID:23414782

Cemented tibial component fixation performs better than cementless fixation: a randomized radiostereometric study comparing porous-coated, hydroxyapatite-coated and cemented tibial components over 5 years.

PubMed

Carlsson, Ake; Björkman, Anders; Besjakov, Jack; Onsten, Ingemar

2005-06-01

The question whether the tibial component of a total knee arthroplasty should be fixed to bone with or without bone cement has not yet been definitely answered. We studied movements between the tibial component and bone by radiostereometry (RSA) in total knee replacement (TKR) for 3 different types of fixation: cemented fixation (C-F), uncemented porous fixation (UC-F) and uncemented porous hydroxyapatite fixation (UCHA-F). 116 patients with osteoarthrosis, who had 146 TKRs, were included in 2 randomized series. The first series included 86 unilateral TKRs stratified into 1 of the 3 types of fixation. The second series included 30 patients who had simultaneous bilateral TKR surgery, and who were stratified into 3 subgroups of pairwise comparisons of the 3 types of fixation. After 5 years 2 knees had been revised, neither of which were due to loosening. 1 UCHA-F knee in the unilateral series showed a large and continuous migration and a poor clinical result, and is a pending failure. The C-F knees rotated and migrated less than UC-F and UCHA-F knees over 5 years. UCHA-F migrated less than UC-F after 1 year. Cementing of the tibial component offers more stable bone-implant contact for 5 years compared to uncemented fixation. When using uncemented components, however, there is evidence that augmenting a porous surface with hydroxyapatite may mean less motion between implant and bone after the initial postoperative year.

Leaching of heavy metals from cementitious composites made of new ternary cements

NASA Astrophysics Data System (ADS)

Kuterasińska-Warwas, Justyna; Król, Anna

2017-10-01

The paper presents a comparison of research methods concerning the leaching of harmful substances (selected heavy metal cations ie. Pb, Cu, Zn and Cr) and their degree of immobilization in cement matrices. The new types of ternary cements were used in the study, where a large proportion of cement clinker was replaced by other non-clinker components - industrial wastes, ie. siliceous fly ash from power industry and granulated blast furnace slag from the iron and steel industry. In studied cementitious binders also ground limestone was used, which is a widely available raw material. The aim of research is determining the suitability of new cements for neutralizing harmful substances in the obtained matrices. The application of two research methods in accordance with EN 12457-4 and NEN 7275 intends to reflection of changing environmental conditions whom composite materials may actually undergo during their exploitation or storing on landfills. The results show that cements with high addition of non-clinker components are suitable for stabilization of toxic substances and the obtained cement matrices retain a high degree of immobilization of heavy metals at the level of 99%.

[APPLICATION AND EFFECTIVENESS OF BIOLOGICAL TYPE ACETABULAR CUP IN ADULT Crowe TYPE IV DEVELOPMENTAL DYSPLASIA OF THE HIP].

PubMed

Xu, Ning; Sun, Junying; Zhao, Xijiang; Wang, Tao

2016-01-01

To investigate the application and effectiveness of the biological type acetabular cup(diameter < 44 mm) in adult Crowe type IV developmental dysplasia of the hip (DDH). Between April 2001 andAugust 2013, biological type acetabular cup was used in total hip arthroplasty for the treatment of Crowe type IV DDH in16 cases (20 hips). There were 3 males and 13 females, aged 31-69 years (mean, 49 years). Unilateral hip was involved in 12cases, and bilateral hips in 4 cases. The patients showed pain of the hip joint and inequality of lower limb (shortening ofaffected limb 1.8-6.0 cm in length, 3.5 cm on average). Acetabular deformity, the relationship and the severity of femoralhead dislocation were comfirmed on the X-ray films. The preoperative Harris score was 34.0 ± 6.9. All patientsachieved healing of incision by first intention, with no complication of infection or neurovascular injury. Sixteen caseswere followed up 4-12 years (mean, 7.5 years). At 2 weeks after operation, dislocation occurred in 2 cases, and were fixedwith plaster for 3 weeks after reduction of the hip. Postoperative X-ray films showed complete reduction of femoral head;the average acetabular coverage of the cup of the weight-bearing area was 98.5% (range, 98.2%-99.1%). The cup from theRanawat triangle was 4.6-7.0 mm (mean, 5.8 mm) in medial shifting, and was 4.5-7.9 mm (mean, 6.2 mm) in elevation,it located at cup lateral surface area inside the iliopectineal line and the Kohler line (< 40%); the cup abduction angle was(45 ± 5)degrees, and the anteversion angle was (10 ± 5)degrees. The other patients had no prosthesis loosening except 1 patient havingextensive acetabular prosthesis loosening because of acetabular osteolysis at 12 years after operation. The hip Harris scorewas significantly improved to 85.0 ± 7.5 at 1 year after operation (t = 14.34, P = 0.01). The acetabular grindingprocess to retain enough bone combined with a small cup of-biological prosthesis treating adult Crowe type IV DDH has theadvantages of satisfactory coverage and initial acetabular fixation, so good early and mid-term effectiveness can be obtained.

Clinical Biomechanics of Wear in Total Hip Arthroplasty

PubMed Central

Callaghan, John J; Pedersen, Douglas R; Johnston, Richard C; Brown, Thomas D

2003-01-01

Complementary clinical and laboratory studies were performed to identify variables associated with polyethylene wear following total hip replacement, and to elucidate the mechanisms responsible for accelerated wear in the total hip arthroplasty construct. Observational cohort studies were performed using a prospective clinical database of more than 4000 consecutive primary total hip arthroplasties performed by a single surgeon, to identify wear-related variables. These variables included head size, acetabular/femoral component impingement, and third body debris. Novel digital edge detection techniques were developed and employed to accurately measure wear, and to determine the relationships of head size and third body debris to acceleration of wear. A novel slidingdistance-coupled finite element model was formulated and employed to examine the mechanisms responsible for wear. The long-term cohort studies demonstrated smaller head sizes to be associated with less wear. Third body debris generated from cable fretting was associated with an increase in wear, osteolysis, and acetabular loosening, especially with larger head sizes. The sliding-distance-coupled finite element model replicated the wear rates occurring in vitro and in vivo, demonstrating the importance of sliding distance on polyethylene wear following total hip arthroplasty. It also demonstrated substantial increases in wear associated with femoral head scratching from third body debris. Further extension of the finite element formulation demonstrated the potential for acetabular component rim damage from impingement wear, and the enhanced potential for third body ingress to the bearing surface with larger head sizes. Edge detection wear measurement techniques demonstrated that early wear rates were predictive of long-term wear rates. These complementary clinical and laboratory investigations have provided insight into 1) the significance of sliding distance and physiologic loci of motion as contributing factors in minimizing wear, 2) the deleterious effects of third body particulates in accelerating wear, 3) the potential for, and factors related to, impingement wear, and 4) the potential advantages and compromises related to the use of larger head sizes in the bearing surface construct. PMID:14575243

Radiographic Underestimation of In Vivo Cup Coverage Provided by Total Hip Arthroplasty for Dysplasia.

PubMed

Nie, Yong; Wang, HaoYang; Huang, ZeYu; Shen, Bin; Kraus, Virginia Byers; Zhou, Zongke

2018-01-01

The accuracy of using 2-dimensional anteroposterior pelvic radiography to assess acetabular cup coverage among patients with developmental dysplasia of the hip after total hip arthroplasty (THA) remains unclear in retrospective clinical studies. A group of 20 patients with developmental dysplasia of the hip (20 hips) underwent cementless THA. During surgery but after acetabular reconstruction, bone wax was pressed onto the uncovered surface of the acetabular cup. A surface model of the bone wax was generated with 3-dimensional scanning. The percentage of the acetabular cup that was covered by intact host acetabular bone in vivo was calculated with modeling software. Acetabular cup coverage also was determined from a postoperative supine anteroposterior pelvic radiograph. The height of the hip center (distance from the center of the femoral head perpendicular to the inter-teardrop line) also was determined from radiographs. Radiographic cup coverage was a mean of 6.93% (SD, 2.47%) lower than in vivo cup coverage for these 20 patients with developmental dysplasia of the hip (P<.001). However, both methods yielded highly correlated measurements for cup coverage (Pearson r=0.761, P<.001). The size of the acetabular cup (P=.001) but not the position of the hip center (high vs normal) was significantly associated with the difference between radiographic and in vivo cup coverage. Two-dimensional radiographically determined cup coverage conservatively reflects in vivo cup coverage and remains an important index (taking 7% underestimation errors and the effect of greater underestimation of larger cup size into account) for assessing the stability of the cup and monitoring for adequate ingrowth of bone. [Orthopedics. 2018; 41(1):e46-e51.]. Copyright 2017, SLACK Incorporated.

The influence of acetabular bone cracks in the press-fit hip replacement: Numerical and experimental analysis.

PubMed

Ramos, A; Duarte, R J; Relvas, C; Completo, A; Simões, J A

2013-07-01

The press-fit hip acetabular prosthesis implantation can cause crack formation in the thin regions surrounding the acetabular. As a consequence the presence of cracks in this region can lead to poor fixation and fibrous tissue formation. Numerical and experimental models of commercial press-fit hip replacements were developed to compare the behavior between the intact and implanted joints. Numerical models with an artificial crack and without crack were considered. The iliac and the femur were created through 3D geometry acquisition based on composite human replicas and 3D-Finite Element models were generated. The mechanical behavior was assessed numerically and experimentally considering the principal strains. The comparison between Finite Element model predictions and experimental measurements revealed a maximum difference of 9%. Similar distribution of the principal strains around the acetabular cavity was obtained for the intact and implanted models. When comparing the Von Mises stresses, it is possible to observe that the intact model is the one that presents the highest stress values in the entire acetabular cavity surface. The crack in the posterior side changes significantly the principal strain distribution, suggesting bone loss after hip replacement. Relatively to micromotions, these were higher on the superior side of the acetabular cavity and can change the implant stability and bone ingrowth. Copyright © 2013 Elsevier Ltd. All rights reserved.

Accuracy of templating the acetabular cup size in Total Hip Replacement using conventional acetate templates on digital radiographs.

PubMed

Krishnamoorthy, Vignesh P; Perumal, Rajamani; Daniel, Alfred J; Poonnoose, Pradeep M

2015-12-01

Templating of the acetabular cup size in Total Hip Replacement (THR) is normally done using conventional radiographs. As these are being replaced by digital radiographs, it has become essential to create a technique of templating using digital films. We describe a technique that involves templating the digital films using the universally available acetate templates for THR without the use of special software. Preoperative digital radiographs of the pelvis were taken with a 30 mm diameter spherical metal ball strapped over the greater trochanter. Using standard acetate templates provided by the implant company on magnified digital radiographs, the size of the metal ball (X mm) and acetabular cup (Y mm) were determined. The size of the acetabular cup to be implanted was estimated using the formula 30*Y/X. The estimated size was compared with the actual size of the cup used at surgery. Using this technique, it was possible to accurately predict the acetabular cup size in 28/40 (70%) of the hips. When the accuracy to within one size was considered, templating was correct in 90% (36/40). When assessed by two independent observers, there was good intra-observer and inter-observer reliability with intra-class correlation coefficient values greater than 0.8. It was possible to accurately and reliably predict the size of the acetabular cup, using acetate templates on digital films, without any digital templates.

A Novel Approach for Treatment of Acetabular Fractures

PubMed Central

Xue, Zichao; Qin, Hui; Ding, Haoliang; An, Zhiquan

2016-01-01

Background There is no single approach that provides adequate exposure for treatment of all types of acetabular fractures. We describe our experience with an easier, relatively less invasive pubic symphysis approach (PSA) for the treatment of acetabular fractures. Material/Methods Between March 2011 and March 2012, fifteen patients with acetabular fracture underwent surgery using the PSA technique. Fracture reduction and treatment outcomes were assessed by clinical and radiological examination. Operation time, intraoperative blood loss and postoperative complications were documented. Results Mean operative time was 222±78 minutes. Average blood loss was 993±361 mL. Anatomical reduction was achieved in all patients. Minimum follow-up period was 31 months. Postoperative hypoesthesia in the area of innervation of the lateral femoral cutaneous nerve was reported in one patient, with spontaneous recovery at one month after surgery. No complications were reported during the follow-up period. At the most recent follow up, clinical outcomes were graded as “excellent” in six patients, “good” in eight patients and “fair” in one patient based on the modified Merle d’Aubigné-Postel score. Conclusions PSA appears to be a timesaving and safe approach for treatment of acetabular fractures that affords good visual access and allows for excellent fracture reduction. Our preliminary results revealed a much lower incidence of complications than traditional approaches, suggesting PSA is an alternative for treatment of acetabular fractures. PMID:27734825

21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... substrates, beads of the same alloy, and in the case of Ti-6Al-4V substrates, fibers of commercially pure titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an average... titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high...

21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... substrates, beads of the same alloy, and in the case of Ti-6Al-4V substrates, fibers of commercially pure titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an average... titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high...

21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... substrates, beads of the same alloy, and in the case of Ti-6Al-4V substrates, fibers of commercially pure titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an average... titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high...

21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... substrates, beads of the same alloy, and in the case of Ti-6Al-4V substrates, fibers of commercially pure titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an average... titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high...

Biomechanical modeling of acetabular component polyethylene stresses, fracture risk, and wear rate following press-fit implantation.

PubMed

Ong, Kevin L; Rundell, Steve; Liepins, Imants; Laurent, Ryan; Markel, David; Kurtz, Steven M

2009-11-01

Press-fit implantation may result in acetabular component deformation between the ischial-ilial columns ("pinching"). The biomechanical and clinical consequences of liner pinching due to press-fit implantation have not been well studied. We compared the effects of pinching on the polyethylene fracture risk, potential wear rate, and stresses for two different thickness liners using computational methods. Line-to-line ("no pinch") reaming and 2 mm underreaming press fit ("pinch") conditions were examined for Trident cups with X3 polyethylene liner wall thicknesses of 5.9 mm (36E) and 3.8 mm (40E). Press-fit cup deformations were measured from a foam block configuration. A hybrid material model, calibrated to experimentally determined stress-strain behavior of sequentially annealed polyethylene, was applied to the computational model. Molecular chain stretch did not exceed the fracture threshold in any cases. Nominal shell pinch of 0.28 mm was estimated to increase the volumetric wear rate by 70% for both cups and peak contact stresses by 140 and 170% for the 5.9 and 3.8 mm-thick liners, respectively. Although pinching increases liner stresses, polyethylene fracture is highly unlikely, and the volumetric wear rates are likely to be low compared to conventional polyethylene. (c) 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Computer-assisted virtual preoperative planning in orthopedic surgery for acetabular fractures based on actual computed tomography data.

PubMed

Wang, Guang-Ye; Huang, Wen-Jun; Song, Qi; Qin, Yun-Tian; Liang, Jin-Feng

2016-12-01

Acetabular fractures have always been very challenging for orthopedic surgeons; therefore, appropriate preoperative evaluation and planning are particularly important. This study aimed to explore the application methods and clinical value of preoperative computer simulation (PCS) in treating pelvic and acetabular fractures. Spiral computed tomography (CT) was performed on 13 patients with pelvic and acetabular fractures, and Digital Imaging and Communications in Medicine (DICOM) data were then input into Mimics software to reconstruct three-dimensional (3D) models of actual pelvic and acetabular fractures for preoperative simulative reduction and fixation, and to simulate each surgical procedure. The times needed for virtual surgical modeling and reduction and fixation were also recorded. The average fracture-modeling time was 45 min (30-70 min), and the average time for bone reduction and fixation was 28 min (16-45 min). Among the surgical approaches planned for these 13 patients, 12 were finally adopted; 12 cases used the simulated surgical fixation, and only 1 case used a partial planned fixation method. PCS can provide accurate surgical plans and data support for actual surgeries.

Comprehension and reproducibility of the Judet and Letournel classification

PubMed Central

Polesello, Giancarlo Cavalli; Nunes, Marcus Aurelius Araujo; Azuaga, Thiago Leonardi; de Queiroz, Marcelo Cavalheiro; Honda, Emerson Kyoshi; Ono, Nelson Keiske

2012-01-01

Objective To evaluate the effectiveness of the method of radiographic interpretation of acetabular fractures, according to the classification of Judet and Letournel, used by a group of residents of Orthopedics at a university hospital. Methods We selected ten orthopedic residents, who were divided into two groups; one group received training in a methodology for the classification of acetabular fractures, which involves transposing the radiographic images to a graphic two-dimensional representation. We classified fifty cases of acetabular fracture on two separate occasions, and determined the intraobserver and interobserver agreement. Result The success rate was 16.2% (10-26%) for the trained group and 22.8% (10-36%) for the untrained group. The mean kappa coefficients for interobserver and intraobserver agreement in the trained group were 0.08 and 0.12, respectively, and for the untrained group, 0.14 and 0.29. Conclusion Training in the method of radiographic interpretation of acetabular fractures was not effective for assisting in the classification of acetabular fractures. Level of evidence I, Testing of previously developed diagnostic criteria on consecutive patients (with universally applied reference "gold" standard). PMID:24453583

Impact of implant size on cement filling in hip resurfacing arthroplasty.

PubMed

de Haan, Roel; Buls, Nico; Scheerlinck, Thierry

2014-01-01

Larger proportions of cement within femoral resurfacing implants might result in thermal bone necrosis. We postulate that smaller components are filled with proportionally more cement, causing an elevated failure rate. A total of 19 femoral heads were fitted with polymeric replicas of ReCap (Biomet) resurfacing components fixed with low-viscosity cement. Two specimens were used for each even size between 40 and 56 mm and one for size 58 mm. All specimens were imaged with computed tomography, and the cement thickness and bone density were analyzed. The average cement mantle thickness was 2.63 mm and was not correlated with the implant size. However, specimen with low bone density had thicker cement mantles regardless of size. The average filling index was 36.65% and was correlated to both implant size and bone density. Smaller implants and specimens with lower bone density contained proportionally more cement than larger implants. According to a linear regression model, bone density but not implant size influenced cement thickness. However, both implant size and bone density had a significant impact on the filling index. Large proportions of cement within the resurfacing head have the potential to generate thermal bone necrosis and implant failure. When considering hip resurfacing in patients with a small femoral head and/or osteoporotic bone, extra care should be taken to avoid thermal bone necrosis, and alternative cementing techniques or even cementless implants should be considered. This study should help delimiting the indications for hip resurfacing and to choose an optimal cementing technique taking implant size into account.

Cemented Volcanic Soils, Martian Spectra and Implications for the Martian Climate

NASA Technical Reports Server (NTRS)

Bishop, J. L.; Schiffman, P.; Drief, A.; Southard, R. J.

2004-01-01

Cemented soils formed via reactions with salts are studied here and provide information about the climate when they formed. Spectroscopic and microprobe studies have been performed on cemented volcanic crusts in order to learn about the composition of these materials, how they formed, and what they can tell us about climatic interactions with surface material on Mars to form cemented soils. These crusts include carbonate, sulfate and opaline components that may all be present in cemented soil units on Mars.

Validation of a measuring technique with computed tomography for cement penetration into trabecular bone underneath the tibial tray in total knee arthroplasty on a cadaver model

PubMed Central

2014-01-01

Background In total knee arthroplasty (TKA), cement penetration between 3 and 5 mm beneath the tibial tray is required to prevent loosening of the tibia component. The objective of this study was to develop and validate a reliable in vivo measuring technique using CT imaging to assess cement distribution and penetration depth in the total area underneath a tibia prosthesis. Methods We defined the radiodensity ranges for trabecular tibia bone, polymethylmethacrylate (PMMA) cement and cement-penetrated trabecular bone and measured the percentages of cement penetration at various depths after cementing two tibia prostheses onto redundant femoral heads. One prosthesis was subsequently removed to examine the influence of the metal tibia prostheses on the quality of the CT images. The percentages of cement penetration in the CT slices were compared with percentages measured with photographs of the corresponding transversal slices. Results Trabecular bone and cement-penetrated trabecular bone had no overlap in quantitative scale of radio-density. There was no significant difference in mean HU values when measuring with or without the tibia prosthesis. The percentages of measured cement-penetrated trabecular bone in the CT slices of the specimen were within the range of percentages that could be expected based on the measurements with the photographs (p = 0.04). Conclusions CT scan images provide valid results in measuring the penetration and distribution of cement into trabecular bone underneath the tibia component of a TKA. Since the proposed method does not turn metal elements into artefacts, it enables clinicians to assess the width and density of the cement mantle in vivo and to compare the results of different cementing methods in TKA. PMID:25158996

[Aseptic, simultaneous and bilateral mobilisation due to an acetabular shell fracture in a 43 year-old patient].

PubMed

Ceretti, M; Fanelli, M; Pappalardo, S

2014-01-01

The acetabular shell mobilization is the main long-term complication in total hip replacement. Metal-back fracture has also to be considered among the possible causes of shell mobilization. A case is presented of bilateral acetabular shell mobilization due to the trabecular covering de-soldering from the metal-back in a 43 year-old patient, 13-14 years after the first surgery. Copyright © 2013 SECOT. Published by Elsevier Espana. All rights reserved.

Can acetabular orientation be restored by lumbar pedicle subtraction osteotomy in ankylosing spondylitis patients with thoracolumbar kyphosis?

PubMed

Hu, Jun; Qian, Bang-Ping; Qiu, Yong; Wang, Bin; Yu, Yang; Zhu, Ze-Zhang; Jiang, Jun; Mao, Sai-Hu; Qu, Zhe; Zhang, Yun-Peng

2017-07-01

To evaluate whether acetabular orientation (abduction and anteversion) can be restored by lumbar pedicle subtraction osteotomy (PSO) in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis. A total of 33 consecutive AS patients with thoracolumbar kyphosis undergoing one-level lumbar PSO were retrospectively reviewed. Radiographical measurements included sagittal vertical axis, global kyphosis, thoracic kyphosis, local kyphosis, lumbar lordosis, pelvic incidence, sacral slope, and pelvic tilt. Acetabular abduction and anteversion were measured on CT scans of the pelvis before and after lumbar PSO. The preoperative and postoperative parameters were compared by the paired samples t test. Pearson's correlation analysis was conducted to determine the correlations between the changes in acetabular abduction and anteversion and the changes in sagittal spinopelvic parameters. After lumbar PSO, sagittal vertical axis, global kyphosis, and pelvic tilt were corrected from 15.7 ± 6.7 cm, 66.8° ± 17.5°, and 38.6° ± 9.0° to 2.9 ± 4.9 cm, 21.3° ± 8.2°, and 23.2° ± 8.2°, respectively (p < 0.001). Of note, acetabular abduction and anteversion decreased from 59.6° ± 4.6° to 31.4° ± 6.5° before surgery to 51.4° ± 6.5° and 20.2° ± 4.4° after surgery, respectively (p < 0.001). Moreover, the changes in acetabular abduction and anteversion were observed significantly correlated with the change in pelvic tilt (r = 0.527, p = 0.002; r = 0.586, p < 0.001). Abnormal acetabular abduction and anteversion could be corrected by lumbar PSO in AS patients with thoracolumbar kyphosis. Consequently, a relatively normal acetabular orientation could be achieved after lumbar PSO, which might decrease the potential risk of dislocation in AS patients with spine and hip deformities requiring subsequent THR surgery.

Six years of continuous intrathecal infusion of opioid and bupivacaine in the treatment of refractory pain due to intrapelvic extrusion of bone cement after total hip arthroplasty.

PubMed

Dahm, P O; Nitescu, P V; Appelgren, L K; Curelaru, I D

1998-01-01

There is at present no reliable method for long-term treatment of severe pain following complications of total hip arthroplasty. We explored the long-term use of continuous intrathecal opioid/bupivacaine analgesia in a case not amendable to corrective surgery. A 77-year-old woman, having a total hip arthroplasty, developed refractory nociceptive-neuropathic pain located at the ventral and dorsal aspects of the left hip. Radiographs showed a mandarine-sized intrapelvic mass of bone cement adhering to the roof of the acetabular cup. Further surgery had been declined by the surgeon and by the patient. An 18-gauge Portex intrathecal catheter was inserted, and an intrathecal infusion of 4.75 mg/mL bupivacaine and 0.015 mg/mL buprenorphine was started from a portable Pharmacia-Deltec (St. Paul, Minnesota) pump. The mean daily doses during the treatment period (more than 6 years up to now) were 37 mg for bupivacaine and 0.114 mg for buprenorphine. The intrathecal treatment gave the patient 85-100% pain relief. The patient could transport herself in a wheelchair, was able to perform her own hygiene, receive visits, read, watch television, and also shop and visit restaurants. There has been no need to replace the intrathecal catheter. Intrathecal infusion of opioid/bupivacaine can provide satisfactory long-term analgesia in patients with refractory pain from the hip joint.

[Significance of bone mineral density and modern cementing technique for in vitro cement penetration in total shoulder arthroplasty].

PubMed

Pape, G; Raiss, P; Kleinschmidt, K; Schuld, C; Mohr, G; Loew, M; Rickert, M

2010-12-01

Loosening of the glenoid component is one of the major causes of failure in total shoulder arthroplasty. Possible risk factors for loosening of cemented components include an eccentric loading, poor bone quality, inadequate cementing technique and insufficient cement penetration. The application of a modern cementing technique has become an established procedure in total hip arthroplasty. The goal of modern cementing techniques in general is to improve the cement-penetration into the cancellous bone. Modern cementing techniques include the cement vacuum-mixing technique, retrograde filling of the cement under pressurisation and the use of a pulsatile lavage system. The main purpose of this study was to analyse cement penetration into the glenoid bone by using modern cement techniques and to investigate the relationship between the bone mineral density (BMD) and the cement penetration. Furthermore we measured the temperature at the glenoid surface before and after jet-lavage of different patients during total shoulder arthroplasty. It is known that the surrounding temperature of the bone has an effect on the polymerisation of the cement. Data from this experiment provide the temperature setting for the in-vitro study. The glenoid surface temperature was measured in 10 patients with a hand-held non-contact temperature measurement device. The bone mineral density was measured by DEXA. Eight paired cadaver scapulae were allocated (n = 16). Each pair comprised two scapulae from one donor (matched-pair design). Two different glenoid components were used, one with pegs and the other with a keel. The glenoids for the in-vitro study were prepared with the bone compaction technique by the same surgeon in all cases. Pulsatile lavage was used to clean the glenoid of blood and bone fragments. Low viscosity bone cement was applied retrogradely into the glenoid by using a syringe. A constant pressure was applied with a modified force sensor impactor. Micro-computed tomography scans were applied to analyse the cement penetration into the cancellous bone. The mean temperature during the in-vivo arthroplasty of the glenoid was 29.4 °C (27.2-31 °C) before and 26.2 °C (25-27.5 °C) after jet-lavage. The overall peak BMD was 0.59 (range 0.33-0.99) g/cm (2). Mean cement penetration was 107.9 (range 67.6-142.3) mm (2) in the peg group and 128.3 (range 102.6-170.8) mm (2) in the keel group. The thickness of the cement layer varied from 0 to 2.1 mm in the pegged group and from 0 to 2.4 mm in the keeled group. A strong negative correlation between BMD and mean cement penetration was found for the peg group (r (2) = -0.834; p < 0.01) and for the keel group (r (2) = -0.727; p < 0.041). Micro-CT shows an inhomogenous dispersion of the cement into the cancellous bone. Data from the in-vivo temperature measurement indicate that the temperature at the glenohumeral surface under operation differs from the body core temperature and should be considered in further in-vitro studies with human specimens. Bone mineral density is negatively correlated to cement penetration in the glenoid. The application of a modern cementing technique in the glenoid provides sufficient cementing penetration although there is an inhomogenous dispersion of the cement. The findings of this study should be considered in further discussions about cementing technique and cement penetration into the cancellous bone of the glenoid. © Georg Thieme Verlag KG Stuttgart · New York.

Surface evaluation of orthopedic hip implants marketed in Brazil

NASA Astrophysics Data System (ADS)

Souza, M. M.; Trommer, R. M.; Maru, M. M.; Roesler, C. R. M.; Barros, W. S.; Dutra, M. S.

2016-07-01

One of the factors that contribute to the quality of total hip prostheses is the degree of accuracy in the manufacturing of the joint surfaces. The dimensional control of joint components is important because of its direct influence on the durability and, consequently, in the patients’ life quality. This work presents studies on the form and roughness of orthopedic hip prostheses marketed in Brazil. The results provide data for quality control of the surfaces of the femoral heads and acetabular components of hip prostheses and indicate the need of improvement in the procedures used to this control.

21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Shoulder joint glenoid (hemi-shoulder) metallic... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket) component...

21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Shoulder joint glenoid (hemi-shoulder) metallic... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket) component...

21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Shoulder joint glenoid (hemi-shoulder) metallic... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket) component...

21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint glenoid (hemi-shoulder) metallic... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket) component...

21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Shoulder joint glenoid (hemi-shoulder) metallic... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket) component...

Mineral of the month: cement

USGS Publications Warehouse

van Oss, Hendrik G.

2006-01-01

Hydraulic cement is a virtually ubiquitous construction material that, when mixed with water, serves as the binder in concrete and most mortars. Only about 13 percent of concrete by weight is cement (the rest being water and aggregates), but the cement contributes all of the concrete’s compressional strength. The term “hydraulic” refers to the cement’s ability to set and harden underwater through the hydration of the cement’s components.

Inversion of the acetabular labrum triggers rapidly destructive osteoarthritis of the hip: representative case report and proposed etiology.

PubMed

Fukui, Kiyokazu; Kaneuji, Ayumi; Fukushima, Mana; Matsumoto, Tadami

2014-12-01

The pathophysiology of rapidly destructive osteoarthritis (OA) of the hip is unknown. This study documented cases of inversion of the acetabular labrum, which has clinicoradiologic features similar to those of initial-stage rapidly destructive hip OA. Our study was based on a prospective review of data for 9 patients with rapidly destructive hip OA. Intraoperative findings showed that the anterosuperior portion of the acetabular labrum had inverted into the articular space, along with many fragments of articular cartilage, in all patients. Subchondral insufficiency fractures of the femoral heads were seen just under the inverted labra in 8 of the 9 patients. Inversion of the acetabular labrum may be involved in rapid joint-space narrowing and subchondral insufficiency fracture in rapidly destructive hip OA. Copyright © 2014 Elsevier Inc. All rights reserved.

Acetabular rim and surface segmentation for hip surgery planning and dysplasia evaluation

NASA Astrophysics Data System (ADS)

Tan, Sovira; Yao, Jianhua; Yao, Lawrence; Summers, Ronald M.; Ward, Michael M.

2008-03-01

Knowledge of the acetabular rim and surface can be invaluable for hip surgery planning and dysplasia evaluation. The acetabular rim can also be used as a landmark for registration purposes. At the present time acetabular features are mostly extracted manually at great cost of time and human labor. Using a recent level set algorithm that can evolve on the surface of a 3D object represented by a triangular mesh we automatically extracted rims and surfaces of acetabulae. The level set is guided by curvature features on the mesh. It can segment portions of a surface that are bounded by a line of extremal curvature (ridgeline or crestline). The rim of the acetabulum is such an extremal curvature line. Our material consists of eight hemi-pelvis surfaces. The algorithm is initiated by putting a small circle (level set seed) at the center of the acetabular surface. Because this surface distinctively has the form of a cup we were able to use the Shape Index feature to automatically extract an approximate center. The circle then expands and deforms so as to take the shape of the acetabular rim. The results were visually inspected. Only minor errors were detected. The algorithm also proved to be robust. Seed placement was satisfactory for the eight hemi-pelvis surfaces without changing any parameters. For the level set evolution we were able to use a single set of parameters for seven out of eight surfaces.

[Quantification of acetabular coverage in normal adult].

PubMed

Lin, R M; Yang, C Y; Yu, C Y; Yang, C R; Chang, G L; Chou, Y L

1991-03-01

Quantification of acetabular coverage is important and can be expressed by superimposition of cartilage tracings on the maximum cross-sectional area of the femoral head. A practical Autolisp program on PC AutoCAD has been developed by us to quantify the acetabular coverage through numerical expression of the images of computed tomography. Thirty adults (60 hips) with normal center-edge angle and acetabular index in plain X ray were randomly selected for serial drops. These slices were prepared with a fixed coordination and in continuous sections of 5 mm in thickness. The contours of the cartilage of each section were digitized into a PC computer and processed by AutoCAD programs to quantify and characterize the acetabular coverage of normal and dysplastic adult hips. We found that a total coverage ratio of greater than 80%, an anterior coverage ratio of greater than 75% and a posterior coverage ratio of greater than 80% can be categorized in a normal group. Polar edge distance is a good indicator for the evaluation of preoperative and postoperative coverage conditions. For standardization and evaluation of acetabular coverage, the most suitable parameters are the total coverage ratio, anterior coverage ratio, posterior coverage ratio and polar edge distance. However, medial coverage and lateral coverage ratios are indispensable in cases of dysplastic hip because variations between them are so great that acetabuloplasty may be impossible. This program can also be used to classify precisely the type of dysplastic hip.

Magnetic resonance imaging with gadolinium arthrography to assess acetabular cartilage delamination.

PubMed

Zaragoza, Edward; Lattanzio, Pierre-Jean; Beaule, Paul E

2009-01-01

Recent reports have demonstrated magnetic resonance imaging (MRI) as a promising technique in detecting articular cartilage lesions of the hip joint. The purpose of our study was to evaluate the diagnostic performance of MRI with gadolinium arthrography in detecting acetabular cartilage delamination in patients with pre-arthritic hip pain. 46 patients (48 hips) underwent surgical dislocation of the hip. Mean age was 38.8 (range 17-56). There were 26 males and 20 females. All patients had Magnetic Resonance Imaging with gadolinium arthrography (MRA) before undergoing open hip surgery where the acetabular cartilage was inspected. Acetabular cartilage delamination on MRA was seen on sagittal images as a linear intra-articular filling defect of low signal intensity >1mm in thickness on T1 weighted images and surrounded by contrast. On MRA all hips had a labral tear confirmed at surgery. At surgery 30 hips had evidence of acetabular cartilage delamination, 4 hips had ulceration and 14 had no articular cartilage damage. The majority of labral tears and cartilage damage were located in the antero-superior quadrant. The sensitivity and specificity of MRA detection of cartilage delamination confirmed at surgery were 97% and 84%, respectively. The positive and negative predictive values of the MRA finding were 90% and 94%, respectively. The presence of the acetabular cartilage delamination represents an early stage of articular cartilage degeneration. When evaluating a young adult with hip pain, labral tears in association with cartilage delamination should be considered. MRA represents an effective diagnostic tool.

High temperature polymer concrete compositions

DOEpatents

Fontana, Jack J.; Reams, Walter

1985-01-01

This invention is concerned with a polymer concrete composition, which is a two-component composition useful with many bases including metal. Component A, the aggregate composition, is broadly composed of silica, silica flour, portland cement, and acrylamide, whereas Component B, which is primarily vinyl and acrylyl reactive monomers, is a liquid system. A preferred formulation emphasizing the major necessary components is as follows: ______________________________________ Component A: Silica sand 60-77 wt. % Silica flour 5-10 wt. % Portland cement 15-25 wt. % Acrylamide 1-5 wt. % Component B: Styrene 50-60 wt. % Trimethylolpropane 35-40 wt. % trimethacrylate ______________________________________ and necessary initiators, accelerators, and surfactants.

Acetabular labral tears in patients with sports injury.

PubMed

Kang, Chan; Hwang, Deuk-Soo; Cha, Soo-Min

2009-12-01

We wanted to investigate acetabular labral tears and their correlation with femoroacetabular impingement in patients with sports injury. Among 111 patients who were diagnosed with the acetabular labral tears after arthroscopic treatment from January 2004 to December 2007, we selected 41 patients with sports injury. There were 12 cases of Taekwondo injury, 5 of golf injury, 4 of soccer injury, 3 of gymnastics injury, 2 of Hapkido injury, 2 of aerobics injury, 2 of rock-climbing injury, 2 of fitness training injury and 9 of other sports injuries. We checked the subtypes of acetabular labral tears and the accompanying femoroacetabular impingement. For the cases with accompanying femoroacetabular impingement, we investigated the subtypes according to the types of sports, gender and age. At last follow-up, we checked the Harris Hip Score (HHS), the Hip Outcome Score (HOS) sports scale and the percentage of patients who returned to their sports activity. The average age of symptomatic onset was 26 years (range, 12 to 65 years). The ratio of males to females was 29 : 12. An average duration of the hip pain was 17 months (range, 1 to 60 months). The degenerative type of acetabular labral tears was the most prevalent with 32 cases (78%), and there were 9 cases (22%) of the partial tear type. Thirty cases (73%) were accompanied by femoroacetabular impingement. The average age of the 23 cases (56%) of the cam-type was 23 years (range, 12 to 48 years), and it was more likely to occur in men (87%) and for people practicing martial arts such as Taekwondo or Hapkido. An average age of the 5 cases (12%) of the pincer-type was 26 (range, 16 to 43 years), it usually occurred in women (60%) and for non-martial arts such as golf and gymnastics. There were 2 cases of the mixed type (cam + pincer-type). At 27 months follow-up, the HHS was 61 to 92 points, the HOS sports scale increased 43 to 75%, and the rate of returning to sports was 71%. In spite of the early expression of symptoms and the short duration of the acetabular labral tears, the high rate of degenerative acetabular labral tears in sports patients is likely associated with repetitive injury after the expression of symptoms. Femoroacetabular impingement in sports patients is seemed to be a cause of the early occurrence of acetabular labral tears. Because the possibility of acetabular labral tears is high in femoroacetabular impingement, sports patients may need to undergo early screening for the diagnosis and care of femoroacetabular impingement.

Failure at the Tibial Cement-Implant Interface With the Use of High-Viscosity Cement in Total Knee Arthroplasty.

PubMed

Kopinski, Judith E; Aggarwal, Ajay; Nunley, Ryan M; Barrack, Robert L; Nam, Denis

2016-11-01

Recent literature has shown debonding of the tibial implant-cement interface as a potential cause for implant loosening. The purpose of this case series is to report this phenomenon in a historically well-performing implant when used with high-viscosity cement (HVC). Thirteen primary cemented Biomet Vanguard total knee arthroplasties were referred to 1 of 2 institutions with complaints of persistent pain after their index procedure. A radiographic and infectious work-up was completed for each patient. All 13 patients underwent a revision of the index surgery with intraoperative diagnosis of tibial component debonding at the implant-cement interface. HVC (Cobalt, DJO Surgical, Vista, CA and Depuy HVC; Depuy Inc, Warsaw, IN) was used in all index cases. The average time to revision surgery for the 13 patients was 2.7 ± 1.9 years from the index surgery. Laboratory infectious markers were within normal in most cases, and all intra-articular aspirations showed no bacterial, fungal, or anaerobic growth. Eleven of 13 patients showed no radiographic evidence of loosening; however, all cases demonstrated tibial component debonding intraoperatively. Given our institution's experience and previously reported data demonstrating excellent survivorship with this total knee arthroplasty prosthesis, we propose that the early failures seen in this case series may be associated with the use of HVC cement. In the setting of a negative infectious work-up and no radiographic evidence to suggest loosening, the surgeon should consider debonding of the tibial component as a potential cause for persistent pain if HVC cement was used with this prosthetic design. Copyright © 2016 Elsevier Inc. All rights reserved.

A new method for the measurement of anteversion of the acetabular cup after total hip arthroplasty.

PubMed

Aydogan, Mehmet; Burç, Halil; Saka, Gursel

2014-08-01

Many methods of determining the anteversion of the acetabular cup have been described in the literature. The advantages and disadvantages of each of these methods are discussed in this paper. We present a new method of measuring the acetabular anteversion at the anteroposterior hip. The formula designed by the authors was anteversion angle (α) = arc sin |PK|/√ |AK| × |BK|. The formula was tested using the AutoCAD software, and an experimental study was conducted to evaluate the accuracy. Three groups were created, and 16 X-ray images were taken and coded. Ten orthopaedic surgeons measured the acetabular anteversion from these X-rays using our formula. The results in Group 1 were closer to the actual value; in contrast, the results in Group 2 differed from the actual values. The results in Group 3 were as close to the actual anteversion values as were those in Group 1. Developments in technology often bring an increase in complications. Despite newly developed surgical methods and technology, the position of the acetabular cup is still used to determine the results of a total hip arthroplasty. Our method is simple, cost-effective and achieves almost 100 % accuracy.

Analysis of the cement clinker produced with incorporation of petroleum sludge

NASA Astrophysics Data System (ADS)

Benlamoudi, A.; Kadir, A. Abdul; Khodja, M.; Nuruddin, M. F.

2018-04-01

Very limited researches have been conducted on the incorporation of petroleum sludge waste into cement clinker production even though this waste may contain similar components to those of clinker raw materials. In this research, petroleum sludge was integrated into cement plant as raw material to produce the cement clinker. As results, incorporation of 5% of this waste was able to produce an acceptable quality of cement. Despite the use of petroleum sludge has decreased the properties of the produced clinker, but it still fit the requirements.

Tribological characteristics of a composite total-surface hip replacement

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.; Roberts, J. C.; Ling, F. F.

1982-01-01

Continuous fiber, woven E glass composite femoral shells having the same elastic properties as bone were fabricated. The shells were then encrusted with filled epoxy wear resistant coatings and run dry against ultrahigh molecular weight polyethylene acetabular cups in 42,000 and 250,000 cycle wear tests on a total hip simulator. The tribological characteristics of these continuous fiber particulate composite femoral shells articulating with ultrahigh molecular weight polyethylene acetabular cups were comparable to those of a vitallium ball articulating with an ultrahigh molecular weight polyethylene acetabular cup.

Stabilization of an acetabular fracture with cables for acute total hip arthroplasty.

PubMed

Mears, D C; Shirahama, M

1998-01-01

A critical stage of total hip arthroplasty for an acute acetabular fracture where extensive comminution, impaction, and osteopenia thwart the application of conventional open or closed methods, especially in the elderly, is stable fixation of the acetabulum. The use of 2-mm braided cables permits effective immobilization of the fracture for use in conjunction with a hybrid arthroplasty. The method is consistent with the use of a conventional arthroplastic incision and is suitable for other applications including the fixation of periprosthetic fractures, bulk allografts, and conventional acetabular fractures.

Direct hip joint distraction during acetabular fracture surgery using the AO universal manipulator.

PubMed

Calafi, L Afshin; Routt, M L Chip

2010-02-01

Certain acetabular fractures may necessitate distraction of the hip joint for removal of intra-articular debris and assessment of reduction. Distraction can be accomplished by manual traction, using a traction table or an AO universal manipulator (UM). The UM is a relatively simple and an inexpensive device that can provide focal distraction in a controlled manner without the risks associated with the use of a traction table. We describe a technique using the UM for hip joint distraction during acetabular fracture surgery through a Kocher-Langenbeck surgical exposure.

One-stage revision of infected hip arthroplasty: outcome of 39 consecutive hips.

PubMed

Ilchmann, Thomas; Zimmerli, Werner; Ochsner, Peter Emil; Kessler, Bernhard; Zwicky, Lukas; Graber, Peter; Clauss, Martin

2016-05-01

There are various options for treating periprosthetic joint infection (PJI). Two-stage exchange has traditionally been the gold standard. However, if the appropriate surgical intervention is chosen according to a rational algorithm, the outcome is similar when using all types of interventions. In an observational cohort study, the outcome of patients with PJI after hip replacement treated with one-stage revision was analysed. All patients fulfilling all criteria for one-stage exchange according to the Infectious Diseases Society of America (IDSA) guidelines and six without preoperative identification of a microorganism were included. Implant removal, debridement and cemented or uncemented reimplantations were performed in a single intervention. If a cemented device was implanted, commercially available gentamicin cement was used in all cases. Antibiotic treatment was administered intravenously for at least 2 weeks, followed by oral therapy for a total duration of 3 months. Patients had standardised clinical and radiological follow-up visits. Between 1996 and 2011, 38 patients (39 hips) were treated with a one-stage procedure and followed for at least 2 years. Coagulase-negative staphylococci were the most frequent pathogens, and polymicrobial infection was observed in five cases. In 25 hips, an uncemented revision stem was implanted, and 37 hips received an acetabular reinforcement ring. The mean follow-up was 6.6 (2.0-15.1) years. No patient had persistent, recurrent or new infection. There were four stem revisions for aseptic loosening. The mean Harris Hip Score was 81 points (26-99) at the final follow-up. Excellent cure rate and function seen in our study suggest that one-stage exchange is a safe procedure, even without local antibiotic treatment, provided that the patient has no sinus tract or severe soft tissue damage, no major bone grafting is required and the microorganism is susceptible to orally administered agents with high bioavailability.

The prevalence of acetabular anomalies associated with pistol-grip-deformity in osteoarthritic hips.

PubMed

Ipach, I; Mittag, F; Walter, C; Syha, R; Wolf, P; Kluba, T

2013-02-01

Acetabular retroversion, excessive acetabular coverage and abnormal head-neck-junction with a so-called "pistol-grip-deformity" were added to the classical description of hip dysplasia to describe pathological hip morphology. The aim of the current study was the detection of pathological acetabular geometry in patients with an abnormal head-neck-junction. Femoroacetabular impingement and hip dysplasia features are frequent in patients with end-stage osteoarthritis before 60 years of age. We analysed our data bank retrospectively for all patients who received a Total Hip Arthroplasty (THA) due to end-stage osteoarthritis before the age of 60 years. The pelvic-views and the Dunn-view of these patients were screened for an abnormal head-neck-junction by measuring the head-ratio and the alpha-angle. An orthopaedic surgeon and a radiologist did this independently. These radiographies were measured for signs of acetabular dysplasia, excessive acetabular coverage and crossing sign. A consecutive series of 135 total hip arthroplasties were performed in patients aged less or equal to 60 years because of end-stage osteoarthritis. From these, 81 patients were classified as having an abnormal head-neck-junction. The mean head-ratio in these 81 patients was 1.52±0.35, the mean alpha-angle was 62.5°±9.3°. The mean CE-angle of these 81 patients was 35.8°±10.4°, the mean CA-angle was 36.7°±5.7°, the mean depth-width ratio was 49.1±10, the mean extrusion index was 19.1±9.2 and the mean CCD-angle was 131.7°±7.3°. Of these 81hips, 14 had isolated pistol-grip-deformity, while 11 hips had associated dysplasia, 38 had excessive acetabular coverage, and 14 had crossing sign. In addition, a crossing sign was identified in four of the 11 dysplastic hips and 19 of the 38 of the hips having excessive acetabular coverage. There was no statistically significant difference in regard to the age between the four groups (P=0.087). In contrast, the hips that had excessive acetabular coverage had increased CE-angle (44.6°±7.2°) and decreased extrusion index (12.6±6.5) (P<0.001), while dysplastic hips had increased roof obliquity (17.5°±4.5°) and increased extrusion index (29.6±9.1), as well as decreased CE-angle (20.7°±3.0°) (P<0.001). There is a high coincidence of radiographic findings associated with an abnormal head-neck-junction consisting in excessive acetabular coverage and retroversion as well as hip dysplasia. These results advocate for restoring of the normal anatomy at the early stage to prevent end-stage osteoarthritis. Level IV retrospective historical study. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

[Effects of Surgically Treated Pelvic Ring and Acetabular Fractures on Postural Control].

PubMed

Lang, P; Schnegelberger, A; Riesner, H-J; Stuby, F; Friemert, B; Palm, H-G

2016-04-01

The aim of surgical treatment of pelvic ring and acetabular fractures is to allow rapid mobilisation of patients in order to restore stance and gait stability (postural control), as this significantly correlates with a positive outcome. The regulation of postural stability is mainly controlled by transmission of proprioceptive stimuli. In addition, the pelvis serves as a connection between the legs and the spine and thus is also of great importance for mechanical stabilisation. It remains unclear whether surgical treatment of pelvic ring and acetabular fractures affects the regulation of postural control. Therefore, the aim of this study was to examine the impact of surgically treated pelvic ring and acetabular fractures on postural stability by means of computerised dynamic posturography (CDP) after a mean of 35 months and to compare the results with a healthy control group. A retrospective case control study of 38 patients with surgically treated pelvic ring and acetabular fractures and 38 healthy volunteers was carried out using CDP. The average time of follow-up was 35 (12-78) months. The most important outcome parameter in this investigation was the overall stability index (OSI). Hip joint mobility, the health-related quality of life (SF-12) and pain were supplementary outcome parameters. It was found that surgically treated pelvic ring and acetabular fractures had no influence on postural stability. The OSI was 2.1 ° in the patient group and 1.9 ° in the control group. There was no significant difference between the groups in hip joint mobility. A total of 52 % of patients showed no or only mild pain. Mean health-related quality of life was the same as in the total population. Surgically treated pelvic ring and acetabular fractures do not lead to deterioration in postural control in the mid term. This is of high prognostic importance for rapid mobilisation of the patients. Therefore no increase in the risk of falling is expected after successfully treatment of fractures. Georg Thieme Verlag KG Stuttgart · New York.

A combination of three-dimensional printing and computer-assisted virtual surgical procedure for preoperative planning of acetabular fracture reduction.

PubMed

Zeng, Canjun; Xing, Weirong; Wu, Zhanglin; Huang, Huajun; Huang, Wenhua

2016-10-01

Treatment of acetabular fractures remains one of the most challenging tasks that orthopaedic surgeons face. An accurate assessment of the injuries and preoperative planning are essential for an excellent reduction. The purpose of this study was to evaluate the feasibility, accuracy and effectiveness of performing 3D printing technology and computer-assisted virtual surgical procedures for preoperative planning in acetabular fractures. We hypothesised that more accurate preoperative planning using 3D printing models will reduce the operation time and significantly improve the outcome of acetabular fracture repair. Ten patients with acetabular fractures were recruited prospectively and examined by CT scanning. A 3-D model of each acetabular fracture was reconstructed with MIMICS14.0 software from the DICOM file of the CT data. Bone fragments were moved and rotated to simulate fracture reduction and restore the pelvic integrity with virtual fixation. The computer-assisted 3D image of the reduced acetabula was printed for surgery simulation and plate pre-bending. The postoperative CT scan was performed to compare the consistency of the preoperative planning with the surgical implants by 3D-superimposition in MIMICS14.0, and evaluated by Matta's method. Computer-based pre-operations were precisely mimicked and consistent with the actual operations in all cases. The pre-bent fixation plates had an anatomical shape specifically fit to the individual pelvis without further bending or adjustment at the time of surgery and fracture reductions were significantly improved. Seven out of 10 patients had a displacement of fracture reduction of less than 1mm; 3 cases had a displacement of fracture reduction between 1 and 2mm. The 3D printing technology combined with virtual surgery for acetabular fractures is feasible, accurate, and effective leading to improved patient-specific preoperative planning and outcome of real surgery. The results provide useful technical tips in planning pelvic surgeries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Does hemipelvis structure and position influence acetabulum orientation?

PubMed

Musielak, Bartosz; Jóźwiak, Marek; Rychlik, Michał; Chen, Brian Po-Jung; Idzior, Maciej; Grzegorzewski, Andrzej

2016-03-16

Although acetabulum orientation is well established anatomically and radiographically, its relation to the innominate bone has rarely been addressed. If explored, it could open the discussion on patomechanisms of such complex disorders as femoroacetabular impingement (FAI). We therefore evaluated the influence of pelvic bone position and structure on acetabular spatial orientation. We describe this relation and its clinical implications. This retrospective study was based on computed tomography scanning of three-dimensional models of 31 consecutive male pelvises (62 acetabulums). All measurements were based on CT spatial reconstruction with the use of highly specialized software (Rhinoceros). Relations between acetabular orientation (inclination, tilt, anteversion angles) and pelvic structure were evaluated. The following parameters were evaluated to assess the pelvic structure: iliac opening angle, iliac tilt angle, interspinous distance (ISD), intertuberous distance (ITD), height of the pelvis (HP), and the ISD/ITD/HP ratio. The linear and nonlinear dependence of the acetabular angles and hemipelvic measurements were examined with Pearson's product - moment correlation and Spearman's rank correlation coefficient. Correlations different from 0 with p < 0.05 were considered statistically significant. Comparison of the axis position with pelvis structure with orientation in the horizontal plane revealed a significant positive correlation between the acetabular anteversion angle and the iliac opening angle (p = 0.041 and 0.008, respectively). In the frontal plane, there was a positive correlation between the acetabular inclination angle and the iliac tilt angle (p = 0.025 and 0.014, respectively) and the acetabular inclination angle and the ISD/ITD/HP ratio (both p = 0.048). There is a significant correlation of the hemipelvic structure and acetabular orientation under anatomic conditions, especially in the frontal and horizontal planes. In the anteroposterior view, the more tilted-down innominate bone causes a more caudally oriented acetabulum axis, whereas in the horizontal view this relation is reversed. This study may serve as a basis for the discussion on the role of the pelvis in common disorders of the hip.

Analysis of acetabular orientation and femoral anteversion using images of three-dimensional reconstructed bone models.

PubMed

Park, Jaeyeong; Kim, Jun-Young; Kim, Hyun Deok; Kim, Young Cheol; Seo, Anna; Je, Minkyu; Mun, Jong Uk; Kim, Bia; Park, Il Hyung; Kim, Shin-Yoon

2017-05-01

Radiographic measurements using two-dimensional (2D) plain radiographs or planes from computed tomography (CT) scans have several drawbacks, while measurements using images of three-dimensional (3D) reconstructed bone models can provide more consistent anthropometric information. We compared the consistency of results using measurements based on images of 3D reconstructed bone models (3D measurements) with those using planes from CT scans (measurements using 2D slice images). Ninety-six of 561 patients who had undergone deep vein thrombosis-CT between January 2013 and November 2014 were randomly selected. We evaluated measurements using 2D slice images and 3D measurements. The images used for 3D reconstruction of bone models were obtained and measured using [Formula: see text] and [Formula: see text] (Materialize, Leuven, Belgium). The mean acetabular inclination, acetabular anteversion and femoral anteversion values on 2D slice images were 42.01[Formula: see text], 18.64[Formula: see text] and 14.44[Formula: see text], respectively, while those using images of 3D reconstructed bone models were 52.80[Formula: see text], 14.98[Formula: see text] and 17.26[Formula: see text]. Intra-rater reliabilities for acetabular inclination, acetabular anteversion, and femoral anteversion on 2D slice images were 0.55, 0.81, and 0.85, respectively, while those for 3D measurements were 0.98, 0.99, and 0.98. Inter-rater reliabilities for acetabular inclination, acetabular anteversion and femoral anteversion on 2D slice images were 0.48, 0.86, and 0.84, respectively, while those for 3D measurements were 0.97, 0.99, and 0.97. The differences between the two measurements are explained by the use of different tools. However, more consistent measurements were possible using the images of 3D reconstructed bone models. Therefore, 3D measurement can be a good alternative to measurement using 2D slice images.

Periacetabular osteotomy: a review of swiss experience.

PubMed

Büchler, Lorenz; Beck, Martin

2014-12-01

Symptomatic dysplasia of the hip and acetabular retroversion are possible causes of osteoarthritis in the young adult. Surgical management with reorientation of the acetabulum allows causal therapy of the deformity and preservation of the native hip joint. The Ganz' periacetabular osteotomy permits a free 3-dimensional reorientation of the acetabulum and respects the blood supply of the acetabular fragment. The posterior column remains intact with a stable fixation of the acetabular fragment and a preserved shape of the true pelvis. There is a significant learning curve with severe complications in up to 30 % of cases. Good results can be expected in the long-term follow-up if performed with correct indication at young age in hips with preserved joint cartilage and proper reorientation of the acetabular fragment. Overall survivorship is superior to the natural course of hip dysplasia with a preserved hip joint in 61 % after 20 years.

Adoption of Robotic vs Fluoroscopic Guidance in Total Hip Arthroplasty: Is Acetabular Positioning Improved in the Learning Curve?

PubMed

Kamara, Eli; Robinson, Jonathon; Bas, Marcel A; Rodriguez, Jose A; Hepinstall, Matthew S

2017-01-01

Acetabulum positioning affects dislocation rates, component impingement, bearing surface wear rates, and need for revision surgery. Novel techniques purport to improve the accuracy and precision of acetabular component position, but may have a significant learning curve. Our aim was to assess whether adopting robotic or fluoroscopic techniques improve acetabulum positioning compared to manual total hip arthroplasty (THA) during the learning curve. Three types of THAs were compared in this retrospective cohort: (1) the first 100 fluoroscopically guided direct anterior THAs (fluoroscopic anterior [FA]) done by a surgeon learning the anterior approach, (2) the first 100 robotic-assisted posterior THAs done by a surgeon learning robotic-assisted surgery (robotic posterior [RP]), and (3) the last 100 manual posterior (MP) THAs done by each surgeon (200 THAs) before adoption of novel techniques. Component position was measured on plain radiographs. Radiographic measurements were taken by 2 blinded observers. The percentage of hips within the surgeons' "target zone" (inclination, 30°-50°; anteversion, 10°-30°) was calculated, along with the percentage within the "safe zone" of Lewinnek (inclination, 30°-50°; anteversion, 5°-25°) and Callanan (inclination, 30°-45°; anteversion, 5°-25°). Relative risk (RR) and absolute risk reduction (ARR) were calculated. Variances (square of the standard deviations) were used to describe the variability of cup position. Seventy-six percentage of MP THAs were within the surgeons' target zone compared with 84% of FA THAs and 97% of RP THAs. This difference was statistically significant, associated with a RR reduction of 87% (RR, 0.13 [0.04-0.40]; P < .01; ARR, 21%; number needed to treat, 5) for RP compared to MP THAs. Compared to FA THAs, RP THAs were associated with a RR reduction of 81% (RR, 0.19 [0.06-0.62]; P < .01; ARR, 13%; number needed to treat, 8). Variances were lower for acetabulum inclination and anteversion in RP THAs (14.0 and 19.5) as compared to the MP (37.5 and 56.3) and FA (24.5 and 54.6) groups. These differences were statistically significant (P < .01). Adoption of robotic techniques delivers significant and immediate improvement in the precision of acetabular component positioning during the learning curve. While fluoroscopy has been shown to be beneficial with experience, a learning curve exists before precision improves significantly. Copyright © 2016 Elsevier Inc. All rights reserved.

Evaluation of the suitability of tin slag in cementitious materials: Mechanical properties and Leaching behaviour

NASA Astrophysics Data System (ADS)

Rustandi, Andi; Wafa' Nawawi, Fuad; Pratesa, Yudha; Cahyadi, Agung

2018-01-01

Tin slag, a by-product of tin production has been used in cementitious application. The present investigation focuses on the suitability of tin slag as primary component in cement and as component that substitute some amount of Portland Cement. The tin slags studied were taken from Bangka, Indonesia. The main contents of the tin slag are SiO2, Al2O3, and Fe2O3 according to the XRF investigation. The aim of this article was to study the mechanical behaviour (compressive strength), microstructure and leaching behaviour of tin slag blended cement. This study used air-cooled tin slag that had been passed through 400# sieve to replace Portland Cement with ratio 0, 10, 20, 30, 40 by weight. Cement pastes and tin slag blended cement pastes were prepared by using water/cement ratio (W/C) of 0.40 by weight and hydrated for various curing ages of 3, 7, 14 days The microstructure of the raw tin slag was investigated using Scanning Electron Microscope (SEM). The phase composition of each cement paste was investigated using X-ray Diffraction (XRD). The aim of the leachability test was to investigate the environmental impacts of tin slag blended cement product in the range 4-8 pH by using static pH-dependent leaching test. The result show that the increase of the tin slag content decreasing the mortar compressive strength at early ages. The use of tin slag in cement provide economic benefits for all related industries.

Cup inclination angle of greater than 50 degrees increases whole blood concentrations of cobalt and chromium ions after metal-on-metal hip resurfacing.

PubMed

Hart, A J; Buddhdev, P; Winship, P; Faria, N; Powell, J J; Skinner, J A

2008-01-01

A cup inclination angle greater than 45 degrees is associated with increased wear rates of metal on polyethylene (MOP) hip replacements. The same maybe true for metal on metal (MOM) hips yet this has not been clearly shown. We measured the acetabular inclination angle from plain radiographs, and whole blood metal ion levels using Inductively Coupled Plasma Mass Spectrometry of 26 patients (mean Harris Hip Score 94 and mean time post op of 22 months) with Birmingham Hip Resurfacings. We identified a threshold level of 50 degrees cup inclination. Below this threshold, the mean whole blood cobalt and chromium were 1.6 ppb and 1.88 ppb respectively; above this threshold, the mean blood cobalt and chromium were 4.45 ppb and 4.3 ppb respectively. These differences were significant cobalt (p<0.01) and chromium (p=0.01). All patients above the threshold had metal levels greater than any of the patients below the threshold. For 14 patients, who returned one year later for a repeat blood metal level measurement, cobalt and chromium levels were very similar. The effect of an acetabular inclination angle of greater than 50 degrees on wear rates of MOM hips, as measured through blood metal ion levels, appears to be similar to that seen with MOP hips. Additionally, our new analytical methods may allow blood metal levels to be used as a realistic biomarker of in vivo wear rate of MOM hips. The implication is that metal levels can be minimised with optimal orientation of the acetabular component.

Mechanical Expansion of Steel Tubing as a Solution to Leaky Wellbores

PubMed Central

Radonjic, Mileva; Kupresan, Darko

2014-01-01

Wellbore cement, a procedural component of wellbore completion operations, primarily provides zonal isolation and mechanical support of the metal pipe (casing), and protects metal components from corrosive fluids. These are essential for uncompromised wellbore integrity. Cements can undergo multiple forms of failure, such as debonding at the cement/rock and cement/metal interfaces, fracturing, and defects within the cement matrix. Failures and defects within the cement will ultimately lead to fluid migration, resulting in inter-zonal fluid migration and premature well abandonment. Currently, there are over 1.8 million operating wells worldwide and over one third of these wells have leak related problems defined as Sustained Casing Pressure (SCP)1. The focus of this research was to develop an experimental setup at bench-scale to explore the effect of mechanical manipulation of wellbore casing-cement composite samples as a potential technology for the remediation of gas leaks. The experimental methodology utilized in this study enabled formation of an impermeable seal at the pipe/cement interface in a simulated wellbore system. Successful nitrogen gas flow-through measurements demonstrated that an existing microannulus was sealed at laboratory experimental conditions and fluid flow prevented by mechanical manipulation of the metal/cement composite sample. Furthermore, this methodology can be applied not only for the remediation of leaky wellbores, but also in plugging and abandonment procedures as well as wellbore completions technology, and potentially preventing negative impacts of wellbores on subsurface and surface environments. PMID:25490436

Mechanical expansion of steel tubing as a solution to leaky wellbores.

PubMed

Radonjic, Mileva; Kupresan, Darko

2014-11-20

Wellbore cement, a procedural component of wellbore completion operations, primarily provides zonal isolation and mechanical support of the metal pipe (casing), and protects metal components from corrosive fluids. These are essential for uncompromised wellbore integrity. Cements can undergo multiple forms of failure, such as debonding at the cement/rock and cement/metal interfaces, fracturing, and defects within the cement matrix. Failures and defects within the cement will ultimately lead to fluid migration, resulting in inter-zonal fluid migration and premature well abandonment. Currently, there are over 1.8 million operating wells worldwide and over one third of these wells have leak related problems defined as Sustained Casing Pressure (SCP). The focus of this research was to develop an experimental setup at bench-scale to explore the effect of mechanical manipulation of wellbore casing-cement composite samples as a potential technology for the remediation of gas leaks. The experimental methodology utilized in this study enabled formation of an impermeable seal at the pipe/cement interface in a simulated wellbore system. Successful nitrogen gas flow-through measurements demonstrated that an existing microannulus was sealed at laboratory experimental conditions and fluid flow prevented by mechanical manipulation of the metal/cement composite sample. Furthermore, this methodology can be applied not only for the remediation of leaky wellbores, but also in plugging and abandonment procedures as well as wellbore completions technology, and potentially preventing negative impacts of wellbores on subsurface and surface environments.

A simple method of measuring the wear of explanted acetabular component inserts

PubMed Central

Krakow, L.; Klockow, A.; Roehner, E.; Brodt, S.; Eijer, H.; Bossert, J.

2017-01-01

Objectives The determination of the volumetric polyethylene wear on explanted material requires complicated equipment, which is not available in many research institutions. Our aim in this study was to present and validate a method that only requires a set of polyetheretherketone balls and a laboratory balance to determine wear. Methods The insert to be measured was placed on a balance, and a ball of the appropriate diameter was inserted. The cavity remaining between the ball and insert caused by wear was filled with contrast medium and the weight of the contrast medium was recorded. The volume was calculated from the known density of the liquid. The precision, inter- and intraobserver reliability, were determined by four investigators on four days using nine inserts with specified wear (0.094 ml to 1.626 ml), and the intra-class correlation coefficient was calculated. The feasibility of using this method in routine clinical practice and the time required for measurement were tested on 84 explanted inserts by one investigator. Results In order to get the mean for all investigators and determinations, the deviation between the measured and specified wear was -0.08 ml (sd 0.12; -0.21 to 0.11). The interobserver reliability was 0.989 ml (95% confidence interval (CI) 0.964 to 0.997) and the intraobserver reliability was 0.941 for observer 1 (95% CI 0.846 to 0.985), 0.983 for observer 2 (95% CI 0.956 to 0.995), 0.939 for observer 3 (95% CI 0.855 to 0.984), and 0.934 for observer 4 (95% CI 0.790 to 0.984). The mean time required to examine the samples was two minutes (sd 2; 1 to 5). Conclusion The method presented here was shown to be sufficiently precise for many settings and is a cost-effective and quick method of determining the volumetric wear of explanted acetabular components. However, the measurement of wear for scientific purposes will probably continue to involve more accurate and dedicated laboratory equipment. Cite this article: L. Krakow, A. Klockow, E. Roehner, S. Brodt, H. Eijer, J. Bossert, G. Matziolis. A simple method of measuring the wear of explanted acetabular component inserts. Bone Joint Res 2017;6:530–534. DOI: 10.1302/2046-3758.69.BJR-2016-0249.R1 PMID:28899855

Arthroscopic treatment of femoral nerve paresthesia caused by an acetabular paralabral cyst.

PubMed

Kanauchi, Taira; Suganuma, Jun; Mochizuki, Ryuta; Uchikawa, Shinichi

2014-05-01

This report describes a rare case of femoral nerve paresthesia caused by an acetabular paralabral cyst of the hip joint. A 68-year-old woman presented with a 6-month history of right hip pain and paresthesia along the anterior thigh and radiating down to the anterior aspect of the knee. Radiography showed osteoarthritis with a narrowed joint space in the right hip joint. Magnetic resonance imaging showed a cyst with low T1- and high T2-weighted signal intensity arising from a labral tear at the anterior aspect of the acetabulum. The cyst was connected to the joint space and displaced the femoral nerve to the anteromedial side. The lesion was diagnosed as an acetabular paralabral cyst causing femoral neuropathy. Because the main symptom was femoral nerve paresthesia and the patient desired a less invasive procedure, arthroscopic labral repair was performed to stop synovial fluid flow to the paralabral cyst that was causing the femoral nerve paresthesia. After surgery, the cyst and femoral nerve paresthesia disappeared. At the 18-month follow-up, the patient had no recurrence. There have been several reports of neurovascular compression caused by the cyst around the hip joint. To the authors' knowledge, only 3 cases of acetabular paralabral cysts causing sciatica have been reported. The current patient appears to represent a rare case of an acetabular paralabral cyst causing femoral nerve paresthesia. The authors suggest that arthroscopic labral repair for an acetabular paralabral cyst causing neuropathy can be an option for patients who desire a less invasive procedure. Copyright 2014, SLACK Incorporated.

Molecular Analysis of Tube Cement of the Biofouling Tubeworm Hydroides elegans

DTIC Science & Technology

2016-03-08

fouler that secretes a tube and strong cement. Little is known about the composition of either of these structures or the genes encoding them. We...the tubeworms cannot attach or can attach only weakly. Cements of H. elegans are secreted during two separate stages of metamorphosis and growth. The...first cements are secreted from the post-trochal region of settling larvae and is a component of a proteinaceous primary tube. This sticky tube is

How often does open reduction and internal fixation of geriatric acetabular fractures lead to hip arthroplasty?

PubMed

O'Toole, Robert V; Hui, Emily; Chandra, Amit; Nascone, Jason W

2014-03-01

We hypothesized that open reduction and internal fixation (ORIF) of displaced acetabular fractures in geriatric patients result in a low rate of conversion to hip arthroplasty and satisfactory hip-specific validated outcome scores at medium-term follow-up. Retrospective review. Level I trauma center. One hundred forty-seven consecutive patients who were 60 years or older who had acetabular fractures were treated at our center from 2001 through 2006. During this time period, fractures meeting operative criteria were treated with ORIF unless medical conditions warranted nonoperative treatment. Twenty-nine patients were lost to follow-up, 46 were deceased, and 11 declined to participate, leaving 61 potential patients for inclusion, 46 of whom were treated with ORIF (average follow-up, 4.4 years; range, 1.1-8.0 years). Standardized telephone interviews included hip-specific questions and validated outcome measures. Rates of conversion to hip arthroplasty and hip-specific validated outcome scores. Among 46 patients treated with ORIF (15 others were treated nonoperatively or with percutaneous screw fixation), 28% underwent hip arthroplasty an average 2.5 years after injury (range, 0.4-5.5 years) and had an average Western Ontario and McMaster Universities Index of Osteoarthritis score of 17 (range, 0-56; n = 38). This score is similar to or better than the typical scores after elective arthroplasty for arthritis and much better than the scores for patients with established arthritis (P < 0.05). The average SF-8 Health Survey physical component score was 46.1 (range, 31-62), similar to US population norms for the geriatric age group (P > 0.20). Few data exist regarding the treatment outcomes for geriatric acetabular fractures. It is difficult for clinicians to decide among ORIF, percutaneous fixation, acute arthroplasty, and nonoperative treatment. Our protocol of mostly ORIF showed a high 1-year mortality rate of 25% and a rate of conversion to arthroplasty after ORIF of 28%. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Absence of a Tourniquet Does Not Affect Fixation of Cemented TKA: A Randomized RSA Study of 70 Patients.

PubMed

Ejaz, Ashir; Laursen, Anders C; Jakobsen, Thomas; Rasmussen, Sten; Nielsen, Poul Torben; Laursen, Mogens B

2015-12-01

We aimed to determine whether not using a tourniquet in cemented TKA would affect migration of the tibial component measured by radiosterometric analysis (RSA). Seventy patients were randomized into a tourniquet group and a non-tourniquet group and using model-based RSA, the migration of the tibial component was analyzed. Primary and secondary outcome measures were maximum total point motion (MTPM) and translations and rotations. Follow-up period was 2 years. The tibial component was well fixated in both groups and no significant difference in migration between the two groups was detected (P=0.632). Mean MTPM (SD) was 0.47 mm (0.16) in the tourniquet group and 0.45 mm (0.21) in the non-tourniquet group. Absence of tourniquet indicates that stable fixation of the tibial component can be achieved in cemented TKA. Copyright © 2015 Elsevier Inc. All rights reserved.

Investigation into three dimensional hip anatomy in anterior dislocation after THA. Influence of the position of the hip rotation centre.

PubMed

Sariali, Elhadi; Klouche, Shahnez; Mamoudy, Patrick

2012-07-01

The components position is a major factor under the surgeon's control in determining the risk of dislocation post total hip arthroplasty. The aim of this study was to investigate the proper three-dimensional components position including the centre of rotation in the case of anterior dislocation. Among 1764 consecutive patients who underwent total hip arthroplasty using a direct anterior approach, 27 experienced anterior dislocation. The three-dimensional hip anatomy was investigated in 12 patients who were paired with 12 patients from the same initial cohort who did not experience dislocation and also with 36 control patients with osteoarthritis. A pelvic Cartesian referential was defined to perform the acetabular analysis. The coordinates were expressed as percentages of the pelvic width, height and depth. The anteversion angles were measured. The hip centre of rotation was significantly shifted medially and posteriorly in the dislocation group when compared to the non-dislocation group and also to the control group. There was no significant difference in component angular position between the dislocation-group and the non-dislocation group. However, the stem anteversion in the dislocation group was increased in comparison to the mean natural femoral anteversion of the control group. A medial and posterior displacement of the hip rotation centre was found to correlate to anterior dislocation post total hip arthoplasty. These results suggest the importance of an accurate restoration of the centre of rotation, whilst avoiding an excessive acetabular reaming which may induce a medial and a posterior displacement. III comparative non randomised. Copyright © 2011 Elsevier Ltd. All rights reserved.

[Modified Exeter technique in revision hip surgery].

PubMed

de Thomasson, E; Guingand, O; Terracher, R; Mazel, C

2008-06-01

The Exeter technique opened new perspectives for the treatment of femoral bone stock loss in revision hip arthroplasty. Implant migration in the cement sheath is, however, a frequent finding. According to the promoters of the technique, this would favor transformation of the allograft into living bone. For others it is a worrisome problem since it alters the heterogeneous cement sheath, leading to loosening and final surgical revision, with an incidence up to 20%. We propose an analysis of the mid-term results of the modified Exeter technique with the objective of cementing the distal part of the implant directly into the recipient bone in order to achieve satisfactory primary stability. The purpose of this work was to analyze the consequences of this method on the long-term evolution of the allograft. After preparing the femur, a specific gun is filled with allograph dough obtained from frozen femoral heads fragmented with an acetabular reamer. The Mersilene mesh enables the deposit of a tube of graft material at the desired level. The implant is sealed after impaction of the graft to enable direct distal cementing in contact with the recipient bone. Partial weight bearing is allowed as early as the fifth day and increased progressively to complete weight bearing at three months. Forty-five patients (46 hips) were treated between June 1996 and January 2002. Six patients were not retained for analysis due to insufficient follow-up. For three patients, graft outcome could not be properly assessed due to a major complication. In addition, two patients died and one was lost to follow-up. In all 39 patients (40 hips) were analyzed at mean follow-up of 84 months (range 48-110). There were no cases of revision for femoral loosening. Femoral bone loss was mainly moderate to severe type II and III hips (Sofcot classification) but limited in height (no grade IV in the Endo-Klinik classification). Clinical outcome was excellent in 13 hips, good in 16, fair in nine and poor in two (Postel-Merle-d'Aubigné score). Defective distal cementing with implant migration (less than 5 mm) was noted in four cases followed by secondary stabilization. Transformation of the allograft occurred in 36 cases, associated with corticalization of the recipient bone in 14. This technique is reproducible since primary stability was obtained in 90% of hips, without hindering transformation of the allograft. The results, which are sustained over time, are the same as with the princeps technique and no radiographic evidence of stress shielding could be found.

Validity and reliability of the Paprosky acetabular defect classification.

PubMed

Yu, Raymond; Hofstaetter, Jochen G; Sullivan, Thomas; Costi, Kerry; Howie, Donald W; Solomon, Lucian B

2013-07-01

The Paprosky acetabular defect classification is widely used but has not been appropriately validated. Reliability of the Paprosky system has not been evaluated in combination with standardized techniques of measurement and scoring. This study evaluated the reliability, teachability, and validity of the Paprosky acetabular defect classification. Preoperative radiographs from a random sample of 83 patients undergoing 85 acetabular revisions were classified by four observers, and their classifications were compared with quantitative intraoperative measurements. Teachability of the classification scheme was tested by dividing the four observers into two groups. The observers in Group 1 underwent three teaching sessions; those in Group 2 underwent one session and the influence of teaching on the accuracy of their classifications was ascertained. Radiographic evaluation showed statistically significant relationships with intraoperative measurements of anterior, medial, and superior acetabular defect sizes. Interobserver reliability improved substantially after teaching and did not improve without it. The weighted kappa coefficient went from 0.56 at Occasion 1 to 0.79 after three teaching sessions in Group 1 observers, and from 0.49 to 0.65 after one teaching session in Group 2 observers. The Paprosky system is valid and shows good reliability when combined with standardized definitions of radiographic landmarks and a structured analysis. Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

The effects of boric acid and phosphoric acid on the compressive strength of glass-ionomer cements.

PubMed

Prentice, Leon H; Tyas, Martin J; Burrow, Michael F

2006-01-01

Both boric acid (H3BO3) and phosphoric acid (H3PO4) are components of dental cements, commonly incorporated into glass (as ingredients in the melt) and occasionally added to the powder or liquid components. This study investigated the effect of boric acid addition to an experimental glass-ionomer powder and the effect of phosphoric acid addition to a glass-ionomer liquid on the 24-h compressive strength. Boric acid powder was added in various concentrations to an experimental glass-ionomer powder and, separately, phosphoric acid was added to an experimental glass-ionomer liquid. Powders and liquids were dosed into capsules at various powder:liquid ratios and cements thus formed were assessed for 24-h compressive strength. Incorporation of boric acid in glass-ionomer powder resulted in a pronounced decrease (p < 0.05 at 1% boric acid) in compressive strength. Addition of phosphoric acid produced initially stronger cements (up to 13% increase at 1% phosphoric acid) before also declining. The incorporation of less than 2% w/w phosphoric acid in glass-ionomer liquids may improve cement strengths without compromising clinical usefulness. The incorporation of boric acid in glass-ionomer cements is contraindicated.

Change in Acetabular Cup Orientation From Supine to Standing Position and Its Effect on Wear of Highly Crosslinked Polyethylene.

PubMed

Teeter, Matthew G; Goyal, Prateek; Yuan, Xunhua; Howard, James L; Lanting, Brent A

2018-01-01

The purpose of this study is to measure acetabular cup position and wear of the highly crosslinked polyethylene liner in the supine and standing position for patients at a minimum of 10 years after the operation. A total of 38 patients were recruited at a mean of 12.5 years after the operation. All patients received a single acetabular cup design with a highly crosslinked liner and a 28-mm cobalt-chromium femoral head. Patients underwent supine and standing radiostereometric examinations in which the X-ray sources and detectors were positioned to obtain an anterior-posterior and cross-table lateral radiograph. Acetabular cup position and the three-dimensional wear rate were measured from the radiographs, and outcome scores were recorded for each patient. Anteversion significantly increased (P < .0001) a mean of 12° from supine (15.1° ± 10.4°) to standing (27.2° ± 10.5°) position. Inclination also significantly increased (P = .001) a mean of 2° from supine (44.4° ± 6.8°) to standing (46.3° ± 7.7°) position. There was no difference (P = .093) in wear rate between supine (0.067 ± 0.070 mm/y) and standing (0.073 ± 0.074 mm/y) positions. There were no correlations between cup orientation and wear rate in either position. Highly crosslinked polyethylene is a forgiving bearing material. Although adherence to the traditional acetabular position target zone is recommended, ensuring hip stability and consideration of the patient's functional position are also important objectives to consider for the acetabular position. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of Cementing on Ligament Balance During Total Knee Arthroplasty.

PubMed

Chow, Jimmy; Wang, Kevin; Elson, Leah; Anderson, Christopher; Roche, Martin

2017-05-01

Complications related to joint imbalance may contribute to some of the most predominant modes of failure in total knee arthroplasty (TKA). These complications include instability, aseptic loosening, asymmetric component wear, and idiopathic pain. Fixation may represent a step that introduces unchecked variability into the procedure and may contribute to the incidence of joint imbalance-related complications. The ability to quantify in vivo loading in the medial and lateral compartments would allow for the ability to confirm balance after fixation and prior to wound closure. This retrospective study sought to capture any variability and imbalance associated with cementing technique. A total of 93 patients underwent sensor-assisted TKA. All patients were confirmed to have quantifiably balanced joints prior to cementation. After cementing and final component placement, the sensor was reinserted into the joint to capture any cementation-induced changes in loading. Imbalance was observed in 44% of patients after cementation. There was no difference in the proportion of imbalance due to surgeon experience (P=.456), cement type (P=.429), or knee system (P=.792). A majority of knees exhibited loading increase in the medial compartment. It was concluded that cementation technique contributes to a significant amount of balance-related variability at the fixation stage of the procedure. The use of the sensor in this study allowed for the correction of all instances of imbalance prior to closure. More objective methods of balance verification may be important for ensuring optimal surgical outcomes. [Orthopedics. 2017; 40(3):e455-e459.]. Copyright 2017, SLACK Incorporated.

Should money follow the patient: Financial implication for being the National Centre for the Treatment and Management of Pelvic and Acetabular Fractures in Ireland.

PubMed

Kelly, M E; Leonard, M; Green, C; Beggs, R; Cheung, C; McElwain, J; Morris, S

2013-12-01

Pelvic and acetabular fractures are complex injuries requiring specialist treatment. Our institution is the National Centre for Treatment and Management of these injuries. To audit all referrals to our institution over a 6-month period and calculate the cost incurred by being the national referral centre. Retrospective review of database, and subsequent allocation of Casemix points to assess total cost of treatment for each patient referred to our institution. 103 patients referred with pelvic or acetabular fracture for operative management. The furthest referral distance was 181miles. Over-all, the length of stay was 15.4 days. The average inclusive cost for a referral to our unit for operative management was €16,302. Pelvic and acetabular fractures are complex injuries that require specialist referral unit management. However for these units to remain sustainable money needs to "follow the patient". Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Sonographic investigation of anatomical specimens of infant hip joints.

PubMed

Falliner, Axel; Hahne, Hans-Jürgen; Hassenpflug, Joachim

2002-07-01

The anatomical foundations of infant hip sonography techniques are ill-defined. We investigated anatomical specimens of infant hip joints in a water bath, with Graf's and Terjesen's methods. Acetabular position was varied in defined increments, with respect to the ultrasound beam. The alpha angles and the femoral head coverage were measured. Plastic acetabular casts were sawn along the sonographic section planes, and the cut sections compared with the sonographic sections. For images to be obtained, which were analysable by the two methods, the ultrasound beam had to intersect with the acetabular inlet plane at defined angles. The acetabular notch had to be anteriorly rotated from the ultrasound beam plane by at least 20 degrees. Beam entry within a 50 degrees sector posterior to the perpendicular on the inlet plane gave analysable images. The alpha angles and femoral head coverage were much affected by coronal-plane transducer tilt. Caudad tilts were associated with lesser values, a fact that should be borne in mind in clinical ultrasound investigations.

[Stress analysis on the acetabular side of bipolar hemiarthroplasty by the two-dimensional finite element method incorporating the boundary friction layer].

PubMed

Ichihashi, K; Imura, S; Oomori, H; Gesso, H

1994-11-01

We compared the biomechanical characteristics of bipolar and unipolar hemiarthroplasty on the proximal migration of the outer head by determining the von Mises stress distribution and acetabular (outer head) displacement with clinical assessment of hemiarthroplasty in 75 patients. This analysis used the two-dimensional finite element method, which incorporated boundary friction layers on both the inner and outer bearings of the prosthesis. Acetabular reaming increased stress within the pelvic bone and migration of the outer head. A combination of the acetabular reaming and bone transplantation increased the stress within the pelvic bone and grafted bone, and caused outer head migration. These findings were supported by clinical results. Although the bipolar endoprosthesis was biomechanically superior to the unipolar endoprosthesis, migration of the outer head still occurred. The bipolar endoprosthesis appeared to be indicated in cases of a femoral neck fracture or of avascular necrosis in the femoral head, but its use in cases of osteoarthritis in the hip required caution.

Perioperative and acute care outcomes in morbidly obese patients with acetabular fractures at a Level 1 trauma center

PubMed Central

Vincent, Heather K.; Haupt, Edward; Tang, Sonya; Egwuatu, Adaeze; Vlasak, Richard; Horodyski, MaryBeth; Carden, Donna; Sadisivan, Kalia K.

2014-01-01

Background Controversy exists regarding obesity-related injury severity and clinical outcomes after orthopedic trauma. Purpose The purposes of this study were to expand our understanding of the effect of morbid obesity on perioperative and acute care outcomes after acetabular fracture. Methods This was a retrospective review of patients with acetabular fracture after trauma. Non-morbidly obese (BMI < 35 kg/m2) and morbidly obese (BMI ≥ 35 kg/m2; N = 81). Injury severity scores and Glasgow Coma Scale scores (GCS) were collected. Perioperative and acute care outcomes were positioning and operative time, extra fractures, estimated blood loss, complications, hospital charges, ventilator days, transfusions, length of stay (LOS) and discharge destination. Positioning and operative times were longer in morbidly obese patients (p < 0.05). No other differences existed between groups. Conclusions Orthopedic trauma surgeons and care teams can expect similar acute care outcomes in morbidly obese and non-morbidly obese patients with acetabular fracture. PMID:25104886

Fixation strength of a polyetheretherketone femoral component in total knee arthroplasty.

PubMed

de Ruiter, Lennert; Janssen, Dennis; Briscoe, Adam; Verdonschot, Nico

2017-11-01

Introducing polyetheretherketone (PEEK) polymer as a material for femoral components in total knee arthroplasty (TKA) could potentially lead to a reduction of the cemented fixation strength. A PEEK implant is more likely to deform under high loads, rendering geometrical locking features less effective. Fixation strength may be enhanced by adding more undercuts or specific surface treatments. The aim of this study is to measure the initial fixation strength and investigate the associated failure patterns of three different iterations of PEEK-OPTIMA ® implants compared with a Cobalt-Chromium (CoCr) component. Femoral components were cemented onto trabecular bone analogue foam blocks and preconditioned with 86,400 cycles of compressive loading (2600 N-260 N at 1 Hz). They were then extracted while the force was measured and the initial failure mechanism was recorded. Four groups were compared: CoCr, regular PEEK, PEEK with an enhanced cement-bonding surface and the latter with additional surface primer. The mean pull-off forces for the four groups were 3814 N, 688 N, 2525 N and 2552 N, respectively. The initial failure patterns for groups 1, 3 and 4 were the same; posterior condylar foam fracture and cement-bone debonding. Implants from group 2 failed at the cement-implant interface. This study has shown that a PEEK-OPTIMA ® femoral TKA component with enhanced macro- and microtexture is able to replicate the main failure mechanism of a conventional CoCr femoral implant. The fixation strength is lower than for a CoCr implant, but substantially higher than loads occurring under in-vivo conditions. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

A novel approach for determining three-dimensional acetabular orientation: results from two hundred subjects.

PubMed

Higgins, Sean W; Spratley, E Meade; Boe, Richard A; Hayes, Curtis W; Jiranek, William A; Wayne, Jennifer S

2014-11-05

The inherently complex three-dimensional morphology of both the pelvis and acetabulum create difficulties in accurately determining acetabular orientation. Our objectives were to develop a reliable and accurate methodology for determining three-dimensional acetabular orientation and to utilize it to describe relevant characteristics of a large population of subjects without apparent hip pathology. High-resolution computed tomography studies of 200 patients previously receiving pelvic scans for indications not related to orthopaedic conditions were selected from our institution's database. Three-dimensional models of each osseous pelvis were generated to extract specific anatomical data sets. A novel computational method was developed to determine standard measures of three-dimensional acetabular orientation within an automatically identified anterior pelvic plane reference frame. Automatically selected points on the osseous ridge of the acetabulum were used to generate a best-fit plane for describing acetabular orientation. Our method showed excellent interobserver and intraobserver agreement (an intraclass correlation coefficient [ICC] of >0.999) and achieved high levels of accuracy. A significant difference between males and females in both anteversion (average, 3.5°; 95% confidence interval [CI], 1.9° to 5.1° across all angular definitions; p < 0.0001) and inclination (1.4°; 95% CI, 0.6° to 2.3° for anatomic angular definition; p < 0.002) was observed. Intrapatient asymmetry in anatomic measures showed bilateral differences in anteversion (maximum, 12.1°) and in inclination (maximum, 10.9°). Significant differences in acetabular orientation between the sexes can be detected only with accurate measurements that account for the entire acetabulum. While a wide range of interpatient acetabular orientations was observed, the majority of subjects had acetabula that were relatively symmetrical in both inclination and anteversion. A highly accurate and reproducible method for determining the orientation of the acetabulum's aperture will benefit both surgeons and patients, by further refining the distinctions between normal and abnormal hip characteristics. Enhanced understanding of the acetabulum could be useful in the diagnostic, planning, and execution stages for surgical procedures of the hip or in advancing the design of new implant systems. Copyright © 2014 by The Journal of Bone and Joint Surgery, Incorporated.

Method for directional hydraulic fracturing

DOEpatents

Swanson, David E.; Daly, Daniel W.

1994-01-01

A method for directional hydraulic fracturing using borehole seals to confine pressurized fluid in planar permeable regions, comprising: placing a sealant in the hole of a structure selected from geologic or cemented formations to fill the space between a permeable planar component and the geologic or cemented formation in the vicinity of the permeable planar component; making a hydraulic connection between the permeable planar component and a pump; permitting the sealant to cure and thereby provide both mechanical and hydraulic confinement to the permeable planar component; and pumping a fluid from the pump into the permeable planar component to internally pressurize the permeable planar component to initiate a fracture in the formation, the fracture being disposed in the same orientation as the permeable planar component.

[Charnley-type total hip prosthesis. Radiological technic of angular measurements of the acetabular piece (anteversion)].

PubMed

Chevrot, A; Najman, G

1983-01-01

A radiological technique is described based on the study of antero-posterior and lateral views of the hip. Mathematical calculations by trigonometry make it possible to deduce the degree of anteversion of the acetabular cup. The necessary tables are given.

Non-autoclaved aerated concrete with mineral additives

NASA Astrophysics Data System (ADS)

Il'ina, L. V.; Rakov, M. A.

2016-01-01

We investigated the effect of joint grinding of Portland cement clinker, silica and carbonate components and mineral additives to specific surface of 280 - 300 m2/kg on the properties (strength, average density and thermal conductivity) of non-autoclaved aerated concrete, and the porosity of the hardened cement paste produced from Portland cement clinker with mineral additives. The joint grinding of the Portland cement clinker with silica and carbonate components and mineral additives reduces the energy consumption of non-autoclaved aerated concrete production. The efficiency of mineral additives (diopside, wollastonite) is due to the closeness the composition, the type of chemical bonds, physical and chemical characteristics (specific enthalpy of formation, specific entropy) to anhydrous clinker minerals and their hydration products. Considering the influence of these additions on hydration of clinker minerals and formation of hardened cement paste structure, dispersed wollastonite and diopside should be used as mineral additives. The hardness and, consequently, the elastic modulus of diopside are higher than that of hardened cement paste. As a result, there is a redistribution of stresses in the hardened cement paste interporous partitions and hardening, both the partitions and aerated concrete on the whole. The mineral additives introduction allowed to obtain the non-autoclaved aerated concrete with average density 580 kg/m3, compressive strength of 3.3 MPa and thermal conductivity of 0.131 W/(m.°C).

Migration of cemented femoral components after THR. Roentgen stereophotogrammetric analysis.

PubMed

Kiss, J; Murray, D W; Turner-Smith, A R; Bithell, J; Bulstrode, C J

1996-09-01

We studied the migration of 58 cemented Hinek femoral components for total hip replacement, using roentgen stereophotogrammetric analysis over four years. The implants migrated faster during the first year than subsequently, and the pattern of migration in the second period was very different. During the first year they subsided, tilted into varus and internally rotated. After this there was slow distal migration with no change in orientation. None of the prostheses has yet failed. The early migration is probably caused by resorption of bone damaged by surgical trauma or the heat generated by the polymerisation of bone cement. Later migration may be due to creep in the bone cement or the surrounding fibrous membrane. The prosthesis which we studied allows the preservation of some of the femoral neck, and comparison with published migration studies of the Charnley stem suggests that this decreases rotation and may help to prevent loosening.

Swellable elastomers under constraint

NASA Astrophysics Data System (ADS)

Lou, Yucun; Robisson, Agathe; Cai, Shengqiang; Suo, Zhigang

2012-08-01

Swellable elastomers are widely used in the oilfield to seal the flow of downhole fluids. For example, when a crack appears in self-healing cement, the liquid in the surroundings flows into the crack and permeates into the cement, causing small particles of elastomers in the cement to swell, resulting in the blocking of the flow. Elastomers are also used as large components in swellable packers, which can swell and seal zones in the borehole. In these applications, the elastomers swell against the constraint of stiff materials, such as cement, metal, and rock. The pressure generated by the elastomer against the confinement is a key factor that affects the quality of the sealing. This work develops a systematic approach to predict the magnitude of the pressure in such components. Experiments are carried out to determine the stress-stretch curve, free swelling ratio, and confining pressure. The data are interpreted in terms of a modified Flory-Rehner model.

Bone Remodeling in Acetabular Reconstruction Using a Kerboull-Type Reinforcement Device and Structural Bone-Grafting in Total Hip Arthroplasty.

PubMed

Oe, Kenichi; Iida, Hirokazu; Tsuda, Kohei; Nakamura, Tomohisa; Okamoto, Naofumi; Ueda, Yusuke

2017-03-01

The purpose of this study was to identify the long-term durability of the Kerboull-type reinforcement device (KT plate) in acetabular reconstruction for massive bone defects, assessing the remodeling of structural bone grafts. This study retrospectively evaluated 106 hips that underwent acetabular reconstruction using a KT plate between November 2000 and December 2010. Thirty-eight primary total hip arthoplasties (THAs) and 68 revised THAs were performed, and the mean duration of clinical follow-up was 8 years (5-14 years). Regarding reconstructing the acetabular bone defects, autografts were used in 37 hips, allografts in 68 hips, and A-W glass ceramics in 2 hips. One hip exhibited radiological migration and no revision for aseptic loosening. The mean Merle d'Aubigné Clinical Score improved from 7.5 points (4-12 points) preoperatively to 10.9 points (9-18 points) at the last follow-up. The Kaplan-Meier survival rate for radiological migration of primary and revised THAs at 10 years was 100% and 97% (95% confidence interval: 96%-100%), respectively. Bone remodeling was evaluated using the radiological demarcation at the bone-to-bone interface, and an improvement of 100% in primary THAs and 94% in revised THAs was observed. For massive bone defects, acetabular reconstruction using the KT plate with a structural bone grafting can yield successful results. Copyright © 2016 Elsevier Inc. All rights reserved.

A new approach for assessment of wear in metal-backed acetabular cups using computed tomography: a phantom study with retrievals.

PubMed

Jedenmalm, Anneli; Noz, Marilyn E; Olivecrona, Henrik; Olivecrona, Lotta; Stark, Andre

2008-04-01

Polyethylene wear is an important cause of aseptic loosening in hip arthroplasty. Detection of significant wear usually happens late on, since available diagnostic techniques are either not sensitive enough or too complicated and expensive for routine use. This study evaluates a new approach for measurement of linear wear of metal-backed acetabular cups using CT as the intended clinically feasible method. 8 retrieved uncemented metal-backed acetabular cups were scanned twice ex vivo using CT. The linear penetration depth of the femoral head into the cup was measured in the CT volumes using dedicated software. Landmark points were placed on the CT images of cup and head, and also on a reference plane in order to calculate the wear vector magnitude and angle to one of the axes. A coordinate-measuring machine was used to test the accuracy of the proposed CT method. For this purpose, the head diameters were also measured by both methods. Accuracy of the CT method for linear wear measurements was 0.6 mm and wear vector angle was 27 degrees . No systematic difference was found between CT scans. This study on explanted acetabular cups shows that CT is capable of reliable measurement of linear wear in acetabular cups at a clinically relevant level of accuracy. It was also possible to use the method for assessment of direction of wear.

Validation of a 3D CT method for measurement of linear wear of acetabular cups.

PubMed

Jedenmalm, Anneli; Nilsson, Fritjof; Noz, Marilyn E; Green, Douglas D; Gedde, Ulf W; Clarke, Ian C; Stark, Andreas; Maguire, Gerald Q; Zeleznik, Michael P; Olivecrona, Henrik

2011-02-01

We evaluated the accuracy and repeatability of a 3D method for polyethylene acetabular cup wear measurements using computed tomography (CT). We propose that the method be used for clinical in vivo assessment of wear in acetabular cups. Ultra-high molecular weight polyethylene cups with a titanium mesh molded on the outside were subjected to wear using a hip simulator. Before and after wear, they were (1) imaged with a CT scanner using a phantom model device, (2) measured using a coordinate measurement machine (CMM), and (3) weighed. CMM was used as the reference method for measurement of femoral head penetration into the cup and for comparison with CT, and gravimetric measurements were used as a reference for both CT and CMM. Femoral head penetration and wear vector angle were studied. The head diameters were also measured with both CMM and CT. The repeatability of the method proposed was evaluated with two repeated measurements using different positions of the phantom in the CT scanner. The accuracy of the 3D CT method for evaluation of linear wear was 0.51 mm and the repeatability was 0.39 mm. Repeatability for wear vector angle was 17°. This study of metal-meshed hip-simulated acetabular cups shows that CT has the capacity for reliable measurement of linear wear of acetabular cups at a clinically relevant level of accuracy.

Multi-pelvis characterisation of articular cartilage geometry.

PubMed

Gillard, Faye C; Dickinson, Alexander S; Schneider, Urs; Taylor, Andrew C; Browne, Martin

2013-12-01

The shape of the acetabular cartilage follows the contact stress distribution across the joint. Accurate characterisation of this geometry may be useful for the development of acetabular cup devices that are more biomechanically compliant. In this study, the geometry of the acetabular cartilage was characterised by taking plaster moulds of the acetabulum from 24 dry bone human pelvises and digitising the mould shapes using a three-dimensional laser scanner. The articular bone surface geometry was analysed, and the shape of the acetabulum was approximated by fitting a best-fit sphere. To test the hypothesis that the acetabulum is non-spherical, a best-fit ellipsoid was also fitted to the geometry. In each case, points around the acetabular notch edge that disclosed the articular surface geometry were identified, and vectors were drawn between these and the best-fit sphere or ellipsoid centre. The significantly larger z radii (into the pole) of the ellipsoids indicated that the acetabulum was non-spherical and could imply that the kinematics of the hip joint is more complex than purely rotational motion, and the traditional ball-and-socket replacement may need to be updated to reflect this motion. The acetabular notch edges were observed to be curved, with males exhibiting deeper, wider and shorter notches than females, although the difference was not statistically significant (mean: p = 0.30) and supports the use of non-gender-specific models in anatomical studies.

Incidence of Ceramic Liner Malseating After Ceramic-on-Ceramic Total Hip Arthroplasty Associated With Osteolysis: A 5- to 15-Year Follow-Up Study.

PubMed

Higuchi, Yoshitoshi; Hasegawa, Yukiharu; Komatsu, Daigo; Seki, Taisuke; Ishiguro, Naoki

2017-05-01

The aim of our study was to evaluate the clinical and radiographic outcomes of malseating of the acetabular liner in ceramic-on-ceramic total hip arthroplasty (THA). Outcomes for 160 ceramic-on-ceramic THAs, contributed by 116 women and 39 men, were evaluated. Clinical and radiographic measurements were obtained over a 5- to 15-year follow-up for analysis. Liner malseating was identified in 20% of cases. Outcomes for 32 cases with liner malseating (group A) were compared to outcomes for 128 joints with correct liner seating (group B). The Harris hip score at the last follow-up was 90.1 for group A and 89.6 for group B. Osteolysis was identified in 5 cases in group A (15.6%), compared to 3 cases in group B (P < .001). No significant between-group differences were identified with regard to ceramic fracture, audible squeaking, loosening of components, and revision THA. The mean annual liner wear rate was comparable between groups, 0.0045 mm/y for group A and 0.0039 mm/y for group B. The 10-year Kaplan-Meier survivorship, based on an end point of revision THA, was 100% for group A and 99.0% for group B. Over a moderate-length follow-up of 5-15 years, malseating of the acetabular liner was not associated with negative clinical outcomes or THA survivorship. Malseating did increase the incidence of osteolysis, a risk factor for adverse effects. Long-term follow-up studies are needed to fully quantify the effects of malseating of the acetabular liner. Copyright © 2016 Elsevier Inc. All rights reserved.

Acetabular Global Insufficiency in Patients with Down Syndrome and Hip-Related Symptoms: A Matched-Cohort Study.

PubMed

Bulat, Evgeny; Maranho, Daniel A; Kalish, Leslie A; Millis, Michael B; Kim, Young-Jo; Novais, Eduardo N

2017-10-18

The etiology of hip instability in Down syndrome is not completely understood. We investigated the morphology of the acetabulum and femur in patients with Down syndrome and compared measurements of the hips with those of matched controls. Computed tomography (CT) images of the pelvis of 42 patients with Down syndrome and hip symptoms were compared with those of 42 age and sex-matched subjects without Down syndrome or history of hip disease who had undergone CT for abdominal pain. Each of the cohorts had 23 male and 19 female subjects. The mean age (and standard deviation) in each cohort was 11.3 ± 5.3 years. The lateral center-edge angle (LCEA), acetabular inclination angle (IA), acetabular depth-width ratio (ADR), acetabular version, and anterior and posterior acetabular sector angles (AASA and PASA) were compared. The neck-shaft angle and femoral version were measured in the patients with Down syndrome only. The hips of the patients with Down syndrome were further categorized as stable (n = 21) or unstable (n = 63) for secondary analysis. The hips in the Down syndrome group had a smaller LCEA (mean, 10.8° ± 12.6° compared with 25.6° ± 4.6°; p < 0.0001), a larger IA (mean, 17.4° ± 10.3° compared with 10.9° ± 4.8°; p < 0.0001), a lower ADR (mean, 231.9 ± 56.2 compared with 306.8 ± 31.0; p < 0.0001), a more retroverted acetabulum (mean acetabular version as measured at the level of the centers of the femoral heads [AVC], 7.8° ± 5.1° compared with 14.0° ± 4.5°; p < 0.0001), a smaller AASA (mean, 55.0° ± 9.9° compared with 59.7° ± 7.8°; p = 0.005), and a smaller PASA (mean, 67.1° ± 10.4° compared with 85.2° ± 6.8°; p < 0.0001). Within the Down syndrome cohort, the unstable hips showed greater femoral anteversion (mean, 32.7° ± 14.6° compared with 23.6° ± 10.6°; p = 0.002) and worse global acetabular insufficiency compared with the stable hips. No differences between the unstable and stable hips were found with respect to acetabular version (mean AVC, 7.8° ± 5.5° compared with 7.6° ± 3.8°; p = 0.93) and the neck-shaft angle (mean, 133.7° ± 6.7° compared with 133.2° ± 6.4°; p = 0.81). Patients with Down syndrome and hip-related symptoms had more retroverted and shallower acetabula with globally reduced coverage of the femoral head compared with age and sex-matched subjects. Hip instability among those with Down syndrome was associated with worse global acetabular insufficiency and increased femoral anteversion, but not with more severe acetabular retroversion. No difference in the mean femoral neck-shaft angle was observed between the stable and unstable hips in the Down syndrome cohort. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Microstructural characterization of dental zinc phosphate cements using combined small angle neutron scattering and microfocus X-ray computed tomography.

PubMed

Viani, Alberto; Sotiriadis, Konstantinos; Kumpová, Ivana; Mancini, Lucia; Appavou, Marie-Sousai

2017-04-01

To characterize the microstructure of two zinc phosphate cement formulations in order to investigate the role of liquid/solid ratio and composition of powder component, on the developed porosity and, consequently, on compressive strength. X-ray powder diffraction with the Rietveld method was used to study the phase composition of zinc oxide powder and cements. Powder component and cement microstructure were investigated with scanning electron microscopy. Small angle neutron scattering (SANS) and microfocus X-ray computed tomography (XmCT) were together employed to characterize porosity and microstructure of dental cements. Compressive strength tests were performed to evaluate their mechanical performance. The beneficial effects obtained by the addition of Al, Mg and B to modulate powder reactivity were mitigated by the crystallization of a Zn aluminate phase not involved in the cement setting reaction. Both cements showed spherical pores with a bimodal distribution at the micro/nano-scale. Pores, containing a low density gel-like phase, developed through segregation of liquid during setting. Increasing liquid/solid ratio from 0.378 to 0.571, increased both SANS and XmCT-derived specific surface area (by 56% and 22%, respectively), porosity (XmCT-derived porosity increased from 3.8% to 5.2%), the relative fraction of large pores ≥50μm, decreased compressive strength from 50±3MPa to 39±3MPa, and favored microstructural and compositional inhomogeneities. Explain aspects of powder design affecting the setting reaction and, in turn, cement performance, to help in optimizing cement formulation. The mechanism behind development of porosity and specific surface area explains mechanical performance, and processes such as erosion and fluoride release/uptake. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Instability after total hip arthroplasty

PubMed Central

Werner, Brian C; Brown, Thomas E

2012-01-01

Instability following total hip arthroplasty (THA) is an unfortunately frequent and serious problem that requires thorough evaluation and preoperative planning before surgical intervention. Prevention through optimal index surgery is of great importance, as the management of an unstable THA is challenging even for an experienced joints surgeon. However, even after well-planned surgery, a significant incidence of recurrent instability still exists. Non-operative management is often successful if the components are well-fixed and correctly positioned in the absence of neurocognitive disorders. If conservative management fails, surgical options include revision of malpositioned components; exchange of modular components such as the femoral head and acetabular liner; bipolar arthroplasty; tripolar arthroplasty; use of a larger femoral head; use of a constrained liner; soft tissue reinforcement and advancement of the greater trochanter. PMID:22919568

Petroleum Sludge as gypsum replacement in cement plants: Its Impact on Cement Strength

NASA Astrophysics Data System (ADS)

Benlamoudi, Ali; Kadir, Aeslina Abdul; Khodja, Mohamed

2017-08-01

Due to high cost of cement manufacturing and the huge amount of resources exhaustion, companies are trying to incorporate alternative raw materials or by-products into cement production so as to produce alternative sustainable cement. Petroleum sludge is a dangerous waste that poses serious imparts on soil and groundwater. Given that this sludge contains a high percentage of anhydrite (CaSO4), which is the main component of gypsum (CaSO4.2H2O), it may play the same gypsum role in strength development. In this research, a total replacement of gypsum (100%) has been substituted by petroleum sludge in cement production and has led to an increase of 28.8% in UCS values after 28 curing days. Nevertheless, the burning of this waste has emitted a considerable amount of carbon monoxide (CO) gas that needs to be carefully considered prior to use petroleum sludge within cement plants.

Biomechanical study of pelvic discontinuity in failed total hip arthroplasty. Lessons learnt from the treatment of pelvic fractures.

PubMed

Ribes-Iborra, Julio; Atienza, Carlos; Sevil-De la Torre, Jorge; Gómez Pérez, Amelia

2017-11-01

Pelvic discontinuity is a rare but serious problem in orthopedic surgery. Acetabular reconstruction in case of severe bone loss after failed total hip arthroplasty is technically difficult, especially in segmental loss type III (anterior or posterior) or pelvic discontinuity (type IV). Acetabular reinforcement devices are frequently used as load-sharing devices to allow allograft incorporation and in order to serve as support of acetabular implants. This study tries to show, by means of biomechanic work, the efficiency of reinforced plate in anterior column in a segmental pelvic loss, illustrated with a clinical case, which shows the socket stability of hip prosthesis. © 2017 Elsevier Ltd. All rights reserved.

Examination and treatment of a professional ballet dancer with a suspected acetabular labral tear: A case report.

PubMed

Khoo-Summers, Lynnette; Bloom, Nancy J

2015-08-01

Dancers are at risk for developing groin pain that is due to acetabular labral tears. Although surgical management of labral tears has been reported extensively, conservative management has been poorly described. This case report describes the examination, diagnosis, and treatment of groin pain in a professional ballet dancer with a suspected acetabular labral tear. Treatment focused on decreasing anterior hip joint stresses and improving the precision of hip motion through correction of alignment and movement impairments noted during functional activities and dance. Successful outcomes included a reduction in pain and return to professional ballet dancing. Copyright © 2015 Elsevier Ltd. All rights reserved.

Revision total hip arthroplasty: the femoral side using cemented implants.

PubMed

Holt, Graeme; Hook, Samantha; Hubble, Matthew

2011-02-01

Advances in surgical technique and implant technology have improved the ten-year survival after primary total hip arthroplasty (THA). Despite this, the number of revision procedures has been increasing in recent years, a trend which is predicted to continue into the future. Revision THA is a technically demanding procedure often complicated by a loss of host bone stock which may be compounded by the need to remove primary implants. Both cemented and uncemented implant designs are commonly used in the United Kingdom for primary and revision THA and much controversy still exists as to the ideal method of stem fixation. In this article we discuss revision of the femur using cemented components during revision THA. We focus on three clinical scenarios including femoral cement-in-cement revision where the primary femoral cement-bone interface remains well fixed, femoral cement-in-cement revision for peri-prosthetic femoral fractures, and femoral impaction grafting. We discuss the clinical indications, surgical techniques and clinical outcomes for each of these procedures.

Constraining the Texture and Composition of Pore-Filling Cements at Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Siebach, K. L.; Grotzinger, J. P.; McLennan, S. M.; Hurowitz, J. A.; Ming, D. W.; Vaniman, D. T.; Rampe, E. B.; Blaney, D. L.; Kah, L. C.

2015-01-01

The Mars Science Laboratory (MSL) rover Curiosity has encountered a wide variety of sedimentary rocks deposited in fluvio-lacuestrine sequences at the base of Gale Crater. The presence of sedimentary rocks requires that initial sediments underwent diagenesis and were lithified. Lithification involves sediment compaction, cementation, and re-crystallization (or authigenic) processes. Analysis of the texture and composition of the cement can reveal the environmental conditions when the cements were deposited, enabling better understanding of early environments present within Gale Crater. The first step in lithification is sediment compaction. The Gale crater sediments do not show evidence for extensive compaction prior to cementation; the Sheepbed mudstone in Yellowknife Bay (YKB) has preserved void spaces ("hollow nodules"), indicating that sediments were cemented around the hollow prior to compaction, and conglomerates show imbrication, indicating minimal grain reorganization prior to lithification. Furthermore, assuming the maximum burial depth of these sediments is equivalent to the depth of Gale Crater, the sediments were never under more than 1 kb of pressure, and assuming a 15 C/km thermal gradient in the late Noachian, the maximum temperature of diagenesis would have been approximately 75 C. This is comparable to shallow burial diagenetic conditions on Earth. The cementation and recrystallization components of lithification are closely intertwined. Cementation describes the precipitation of minerals between grains from pore fluids, and recrystallization (or authigenesis) is when the original sedimentary mineral grains are altered into secondary minerals. The presence of authigenic smectites and magnetite in the YKB formation suggests that some recrystallization has taken place. The relatively high percentage of XRD-amorphous material (25-40%) detected by CheMin suggests that this recrystallization may be limited in scope, and therefore may not contribute significantly to the cementing material. However, relatively persistent amorphous components could exist in the Martian environment (e.g. amorphous MgSO4), so recrystallization, including loss of crystallinity, cannot yet be excluded as a method of cementation. In order to describe the rock cementation, both the rock textures and their composition must be considered. Here, we attempt to summarize the current understanding of the textural and compositional aspects of the cement across the rocks analyzed by Curiosity to this point.

Morphological experimental study of bone stress at the interface acetabular bone/prosthetic cup in the bipolar hip prosthesis.

PubMed

Anuşca, D; Pleşea, I E; Iliescu, N; Tomescu, P; Poenaru, F; Dascălu, V; Pop, O T

2006-01-01

By calculating the tension and distortion of the elements composing the bipolar prosthesis under extreme conditions encountered in real life using a special post-processing program, we established the variation curves of the contact pressure at the hip bone-cup, armor-cup and cup-femoral head interface. By comparing the data obtained from all the examined cases, important conclusions were drawn regarding the influence of tension and pressure distribution on the structural integrity and biomechanics of the prosthesis, as well as the acetabular wear and tear, in order to assess its reliability. The experimentally determined tension and distortion status at the acetabular bone-metal armour interface, lead to the wear and tear phenomenon, which can be explained by three mechanisms and theories incompletely reflecting the overall process. The histopathologic study of the acetabular bone tissue using FEM (finite elements method) on surgically removed specimens will probably lead to the identification of a series of factors that could reduce the rate of the wear and tear process.

Validation of a 3D CT method for measurement of linear wear of acetabular cups

PubMed Central

2011-01-01

Background We evaluated the accuracy and repeatability of a 3D method for polyethylene acetabular cup wear measurements using computed tomography (CT). We propose that the method be used for clinical in vivo assessment of wear in acetabular cups. Material and methods Ultra-high molecular weight polyethylene cups with a titanium mesh molded on the outside were subjected to wear using a hip simulator. Before and after wear, they were (1) imaged with a CT scanner using a phantom model device, (2) measured using a coordinate measurement machine (CMM), and (3) weighed. CMM was used as the reference method for measurement of femoral head penetration into the cup and for comparison with CT, and gravimetric measurements were used as a reference for both CT and CMM. Femoral head penetration and wear vector angle were studied. The head diameters were also measured with both CMM and CT. The repeatability of the method proposed was evaluated with two repeated measurements using different positions of the phantom in the CT scanner. Results The accuracy of the 3D CT method for evaluation of linear wear was 0.51 mm and the repeatability was 0.39 mm. Repeatability for wear vector angle was 17°. Interpretation This study of metal-meshed hip-simulated acetabular cups shows that CT has the capacity for reliable measurement of linear wear of acetabular cups at a clinically relevant level of accuracy. PMID:21281259

Modified pavement cement concrete

NASA Astrophysics Data System (ADS)

Botsman, L. N.; Ageeva, M. S.; Botsman, A. N.; Shapovalov, S. M.

2018-03-01

The paper suggests design principles of pavement cement concrete, which covers optimization of compositions and structures at the stage of mixture components selection due to the use of plasticizing agents and air-retaining substances that increase the viability of a concrete mixture. It also demonstrates advisability of using plasticizing agents together with air-retaining substances when developing pavement concrete compositions, which provides for the improvement of physical and mechanical properties of concrete and the reduction of cement binding agent consumption thus preserving strength indicators. The paper shows dependences of the main physical-mechanical parameters of concrete on cement consumption, a type and amount of additives.

Evaluation of late redislocation in patients who underwent open reduction and pelvic osteotomy as treament for developmental dysplasia of the hip.

PubMed

Tuhanioğlu, Ümit; Cicek, Hakan; Ogur, Hasan U; Seyfettinoglu, Firat; Kapukaya, Ahmet

2017-10-16

The goal in the treatment of developmental dysplasia of the hip (DDH) is to achieve a stable and concentric reduction and to create a congruent relationship between the femoral head and the acetabulum. This study discusses the causes of loss of reduction in DDH patients who had a concentrically reduced hip at the time of removal of the hip spica cast and cessation of brace use and who later appeared with hip redislocation after mobilisation and ambulation. In addition, the possible interventions in such cases are also discussed. A retrospective evaluation was made of 13 patients diagnosed with DDH who developed redislocation following primary surgery. 6 of them had undergone the 1st surgery in our department between 2008 and 2016 and 7 had udergone surgery in another centre. For comparison reasons a 2nd group was formed of 13 demographically and clinically matched patients who had no loss of reduction. The groups were compared in terms of acetabular index, pelvic length, pelvic width, abduction degree of plaster, ossifying nucleus diameter, acetabular depth, and acetabular volume parameters. The average age of the patients was 23 months at initial surgery and 29 months at the time of revision surgery. No significant difference was found between the groups in terms of acetabular inclination angle, ossifying nucleus diameter, pelvic size, pelvic width, centre edge angle, acetabular volume, and depth. Contracted inferomedial capsule was found in 1 patient who underwent revision surgery and intact transverse acetabular ligament was seen in 1 patient. The loss of reduction in the remaining 11 patients was associated with high total anteversion of the femoral head and acetabulum. Correction of increased combined anteversion by femoral osteotomy can create a safe zone in terms of redislocation and can significantly contribute to the stability provided by capsulorrhaphy and pelvic osteotomy.

Biochemical and Cellular Assessment of Acetabular Chondral Flaps Identified During Hip Arthroscopy.

PubMed

Hariri, Sanaz; Truntzer, Jeremy; Smith, Robert Lane; Safran, Marc R

2015-06-01

To analyze chondral flaps debrided during hip arthroscopy to determine their biochemical and cellular composition. Thirty-one full-thickness acetabular chondral flaps were collected during hip arthroscopy. Biochemical analysis was undertaken in 21 flaps from 20 patients, and cellular viability was determined in 10 flaps from 10 patients. Biochemical analysis included concentrations of (1) DNA (an indicator of chondrocyte content), (2) hydroxyproline (an indicator of collagen content), and (3) glycosaminoglycan (an indicator of chondrocyte biosynthesis). Higher values for these parameters indicated more healthy tissue. The flaps were examined to determine the percentage of viable chondrocytes. The percentage of acetabular chondral flap specimens that had concentrations within 1 SD of the mean values reported in previous normal cartilage studies was 38% for DNA, 0% for glycosaminoglycan, and 43% for hydroxyproline. The average cellular viability of our acetabular chondral flap specimens was 39% (SD, 14%). Only 2 of the 10 specimens had more than half the cells still viable. There was no correlation between (1) the gross examination of the joint or knowledge of the patient's demographic characteristics and symptoms and (2) biochemical properties and cell viability of the flap, with one exception: a degenerative appearance of the surrounding cartilage correlated with a higher hydroxyproline concentration. Although full-thickness acetabular chondral flaps can appear normal grossly, the biochemical properties and percentage of live chondrocytes in full-thickness chondral flaps encountered in hip arthroscopy show that this tissue is not normal. There has been recent interest in repairing chondral flaps encountered during hip arthroscopy. These data suggest that acetabular chondral flaps are not biochemically and cellularly normal. Although these flaps may still be valuable mechanically and/or as a scaffold in some conductive or inductive capacity, further study is required to assess the clinical benefit of repair. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

The use of an Ossis custom 3D-printed tri-flanged acetabular implant for major bone loss: minimum 2-year follow-up: Short title: Ossis custom 3D-Printed tri-flanged acetabular implant.

PubMed

Kieser, David C; Ailabouni, Ramez; Kieser, Sandra C J; Wyatt, Michael C; Armour, Paul C; Coates, Mark H; Hooper, Gary J

2018-05-01

Custom 3D-printed acetabular implants are a new technology used in hip surgery with ever-increasing frequency. They offer patient-specific implants to optimise filling of bone defects and implant-bone contact, without the need for excessive bone resection. This is a retrospective cohort study of 46 consecutive patients who underwent an Ossis unilateral custom 3D-printed acetabular implant. Clinical (Oxford Hip Score OHS-60), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS) and radiological (restoration of biomechanical hip centre, osteointegration, wear, heterotrophic ossification) results were assessed. Patient mean age was 68 years and follow-up was 38 months (minimum 24 months). 10 patients were excluded from the outcome analysis; 2 patients died, 1 required revision for deep infection and 7 were lost to follow-up. Of the 36 patients included, 21 had severe osteolysis. 7 were revised for infection, 3 for tumoural defects, 3 for metallosis, 1 for dysplasia and 1 for trauma (Paprosky 2a [n=6], 2b [n=2], 2c [n=5], 3a [n=6], 3b [n=11], pelvic dissociation [n=6]). OHS significantly improved postoperatively (16-8-48.4 p=0.027). Postoperative functional scores were good (WOMAC 98; HHS 79). The biomechanical hip centre was restored in all patients. 1 patient had early implant migration with subsequent stabilisation. 2 patients had radiographs concerning for failure of osteointegration. 1 patient had recurrent dislocations. The mid-term results of the Ossis custom 3D-printed tri-flanged acetabular implant for the management of severe acetabular defects are encouraging. The improvement in functional scores and radiographic outcomes are comparable to similar designs. In addition, no cases have required revision for aseptic loosening.

[One-stage operation for pelvis and acetabular fractures combined with Morel-Lavallée injury by internal fixation associated with vacuum sealing drainage].

PubMed

Wei, Dan; Wang, Yue; Yuan, Jiabin; Tang, Xiaoming; Zhang, Bin; Lu, Bing; Tan, Bo

2014-01-01

To investigate the methods and effectiveness of one-stage operation for pelvis and acetabular fractures combined with Morel-Lavallée injury by internal fixation associated with vacuum sealing drainage (VSD). Between June 2008 and October 2012, 15 cases of pelvis and acetabular fractures combined with Morel-Lavallée injury were treated. There were 5 males and 10 females, aged from 18 to 67 years (mean, 36.8 years). Fractures were caused by traffic accident in 11 cases and crashing injury of heavy object in 4 cases. The time from injury to hospitalization was 3 hours to 9 days (mean, 5.4 days). Morel-Lavallée injury located in the above posterior superior iliac spine in 4 cases, greater trochanter in 7 cases, and anterior proximal thigh in 4 cases. In 10 cases complicated by pelvic fracture, there were 1 case of anteroposterior compression type, 3 cases of lateral compression type, 5 cases of vertical shear type, and 1 case of compound injury type; in 5 cases complicated by acetabular fracture, there were 1 case of transverse fracture, 1 case of posterior wall and posterior column fracture, 1 case of transverse acetabulum plus posterior wall fracture, and 2 cases of both columns fracture. Open reduction and internal fixation were used to treat pelvic and acetabular fractures, and VSD to treat Morel-Lavallée injury. When the drainage volume was less than 20 mL/d, interrupted wound suture or free skin grafting was performed. The hospitalization time was 16-31 days (mean, 20.8 days). Thirteen cases were followed up 4-16 months (mean, 7.8 months). The healing time of Morel-Lavallée injury was 16-36 days after operation (mean, 21.3 days). All the wounds had primary healing, and no infection occurred. The X-ray films showed that all fractures healed, with a mean healing time of 13.6 weeks (range, 11-18 weeks). At 6.5 months after operation, according to Majeed function scoring system in 8 cases of pelvic fracture, the results were excellent in 5 cases, good in 2 cases, and fair in 1 case; according to Harris hip scoring in 4 cases of acetabular fracture, the results were excellent in 2 cases, good in 1 case, and fair in 1 case. To pelvis-acetabular fractures combined with Morel-Lavallée injury, internal fixation treatment for fracture and VSD for Morel-Lavallée injury not only can cure merge Morel-Lavallée injury effectively, but also can guarantee the operation timing and incision safty of the pelvis-acetabular fractures.

Space orientation of total hip prosthesis. A method for three-dimensional determination.

PubMed

Herrlin, K; Selvik, G; Pettersson, H

1986-01-01

A method for in vivo determination of orientation and relation in space of components of total hip prosthesis is described. The method allows for determination of the orientation of the prosthetic components in well defined anatomic planes of the body. Furthermore the range of free motion from neutral position to the point of contact between the edge of the acetabular opening and the neck of the femoral component can be determined in various directions. To assess the accuracy of the calculations a phantom prosthesis was studied in nine different positions and the measurements of the space oriented parameters according to the present method correlated to measurements of the same parameters according to Selvik's stereophotogrammetric method. Good correlation was found. The role of prosthetic malpositioning and component interaction evaluated with the present method in the development of prosthetic loosening and displacement is discussed.

Estimation of appropriate lubricating film thickness in ceramic-on-ceramic hip prostheses

NASA Astrophysics Data System (ADS)

Tauviqirrahman, M.; Muchammad, Bayuseno, A. P.; Ismail, R.; Saputra, E.; Jamari, J.

2016-04-01

Artificial hip prostheses, consisting of femoral head and acetabular cup are widely used and have affected the lives of many people.However, the primary issue associated with the long term performance of hip prostheses is loosening induced by excessive wear during daily activity. Therefore, an effective lubrication is necessary to significantly decrease the wear. To help understand the lubricating performance of such typical hip joint prostheses, in the present paper a hydrodynamic lubrication model based on Reynolds equationwas introduced. The material pairs of ceramic acetabular cup against ceramic femoral head was investegated.The main aim of this study is to investigate of the effect of loading on the formation of lubricating film thickness.The model of a ball-in-socket configuration was considered assuming that the cup was stationary while the ball was to rotate at a steady angular velocityvarying loads.Based on simulation result, it was found that to promote fluid film lubrication and prevent the contacting components leading to wear, the film thickness of lubricant should be determined carefully based on the load applied. This finding may have useful implication in predicting the failure of lubricating synovial fluid film and wear generation in hip prostheses.

Kinematic alignment technique for total hip and knee arthroplasty

PubMed Central

Rivière, Charles; Lazic, Stefan; Villet, Loïc; Wiart, Yann; Allwood, Sarah Muirhead; Cobb, Justin

2018-01-01

Conventional techniques for hip and knee arthroplasty have led to good long-term clinical outcomes, but complications remain despite better surgical precision and improvements in implant design and quality. Technological improvements and a better understanding of joint kinematics have facilitated the progression to ‘personalized’ implant positioning (kinematic alignment) for total hip (THA) and knee (TKA) arthroplasty, the true value of which remains to be determined. By achieving a true knee resurfacing, the kinematic alignment (KA) technique for TKA aims at aligning the components with the physiological kinematic axes of the knee and restoring the constitutional tibio-femoral joint line frontal and axial orientation and soft-tissue laxity. The KA technique for THA aims at restoring the native ‘combined femoro-acetabular anteversion’ and the hip’s centre of rotation, and occasionally adjusting the cup position and design based on the assessment of the individual spine-hip relation. The key element for optimal prosthetic joint kinematics (hip or knee) is to reproduce the femoral anatomy. The transverse acetabular ligament (TAL) is the reference landmark to adjust the cup position. Cite this article: EFORT Open Rev 2018;3:98-105. DOI: 10.1302/2058-5241.3.170022 PMID:29657851

A Peridynamic Approach for Nanoscratch Simulation of the Cement Mortar

NASA Astrophysics Data System (ADS)

Zhao, Jingjing; Zhang, Qing; Lu, Guangda; Chen, Depeng

2018-03-01

The present study develops a peridynamic approach for simulating the nanoscratch procedure on the cement mortar interface. In this approach, the cement and sand are considered as discrete particles with certain mechanical properties on the nanoscale. Besides, the interaction force functions for different components in the interface are represented by combining the van der Waals force and the peridynamic force. The nanoscratch procedures with the indenter moving along certain direction either parallel or perpendicular to the interface are simulated in this paper. The simulation results show the damage evolution processes and the final damage distributions of the cement mortar under different scratching speed and depth of the indenter, indicating that the interface between cement and sand is a weak area.

Morphometric assessment of hip dysplasia in a cat treated by juvenile pubic symphysiodesis.

PubMed

Lai, Alen; Culvenor, John; Bailey, Craig

2016-09-20

To quantitatively evaluate the change of the coxofemoral joints using computed tomography and distraction index in a cat with hip dysplasia treated by juvenile pubic symphysiodesis. Case report. Eighteen-week-old female entire Maine Coon cat. Juvenile pubic symphysiodesis resulted in changes in the distraction index, acetabular angle, dorsal acetabular rim angle, dorsal acetabular sector angle, and clinical improvement at the six month follow-up. No intra-operative or postoperative complications were recorded. Juvenile pubic symphysiodesis performed at 18 weeks of age resulted in improvement in hip joint conformation and hip laxity in a dysplastic cat. Juvenile pubic symphysiodesis may be a promising treatment for feline hip dysplasia and is a safe and technically simple procedure to perform. Further investigations are warranted.

Sex assessment from the acetabular rim by means of image analysis.

PubMed

Benazzi, S; Maestri, C; Parisini, S; Vecchi, F; Gruppioni, G

2008-08-25

Determining sex from skeletal remains is one of the most important steps in archaeological and forensic anthropology. The present study considers the diagnostic value of the acetabulum based on its planar image and related metric data. For this purpose, 83 adult os coxae of known age were examined. Digital photos of the acetabular area were taken, with each bone in a standardized orientation. Technical drawing software was used to trace the acetabular rim and to measure the related dimensions (area, perimeter, longitudinal and transverse maximum width). The measurements were subjected to SPSS discriminant and classification function analysis. There were significant differences (p

Initial mechanical stability of cementless highly-porous titanium tibial components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, Timothy Brandon; Amer, Luke D; Warren, Christopher P

Cementless fixation in total knee replacement has seen limited use since reports of early failure surfaced in the late 80s and early 90s. However the emergence of improved biomaterials, particularly porous titanium and tantalum, has led to a renewed interest in developing a cementless tibial component to enhance long-term survivorship of the implants. Cement is commonly employed to minimize micromotion in new implants but represents a weak interface between the implant and bone. The elimination of cement and application of these new biomaterials, which theoretically provide improved stability and ultimate osseointegration, would likely result in greater knee replacement success. Additionally,more » the removal of cement from the procedure would help minimize surgical durations and get rid of the time needed for curing, thereby the chance of infection. The purpose of this biomechanical study was twofold. The first goal was to assess whether vibration analysis techniques can be used to evaluate and characterize initial mechanical stability of cementless implants more accurately than the traditional method of micromotion determination, which employs linear variable differential transducers (LVDTs). Second, an evaluative study was performed to determine the comparative mechanical stability of five designs of cementless tibial components under mechanical loading designed to simulate in vivo forces. The test groups will include a cemented Triathlon Keeled baseplate control group, three different 2-peg cementless baseplates with smooth, mid, and high roughnesses and a 4-peg cement/ess baseplate with mid-roughness.« less

Effect of lavage and brush preparation on cement penetration and primary stability in tibial unicompartmental total knee arthroplasty: An experimental cadaver study.

PubMed

Scheele, Christian; Pietschmann, Matthias F; Schröder, Christian; Grupp, Thomas; Holderied, Melanie; Jansson, Volmar; Müller, Peter E

2017-03-01

Unicompartmental total knee arthroplasty (UKA) is a well-established treatment option for unicondylar osteoarthritis, and generally leads to better functional results than tricompartimental total knee arthroplasty (TKA). However, revision rates of UKAs are reported as being higher; a major reason for this is aseptic loosening of the tibial component due to implant-cement-bone interface fatigue. The objective of this study was to determine the effects of trabecular bone preparation, prior to implantation of tibial UKAs, on morphological and biomechanical outcomes in a cadaver study. Cemented UKAs were performed in 18 human cadaver knees after the bone bed was cleaned using pulsed lavage (Group A), conventional brush (Group B) or no cleaning at all (Group C, control). Morphologic cement penetration and primary stability were measured. The area proportion under the tibial component without visible cement penetration was significantly higher in Group C (21.9%, SD 11.9) than in both Group A (7.1%, SD 5.8), and Group B (6.5%, SD 4.2) (P=0.007). The overall cement penetration depth did not differ between groups. However, in the posterior part, cement penetration depth was significantly higher in Group B (1.9mm, SD 0.3) than in both Group A (1.3mm, SD 0.3) and Group C (1.4mm, SD 0.3) (P=0.015). The mode of preparation did not show a substantial effect on primary stability tested under dynamic compression-shear test conditions (P=0.910). Bone preparation significantly enhances cement interdigitation. The application of a brush shows similar results compared with the application of pulsed lavage. Copyright © 2016 Elsevier B.V. All rights reserved.

Hip and knee replacement in osteogenesis imperfecta.

PubMed

Papagelopoulos, P J; Morrey, B F

1993-04-01

Five total hip and three total knee arthroplasties were performed, from 1969 to 1990, in six patients who had osteogenesis imperfecta. The patients who had a hip arthroplasty were followed for a mean of seven years, and those who had a knee arthroplasty, for a mean of ten years. Postoperatively, all had relief of pain and were able to walk; one patient used a walker and two used a cane. The only postoperative complication was an intrapelvic protrusion of the acetabular component six years after a bipolar hip replacement.

Diagnosis and management of the infected total joint arthroplasty

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cuckler, J.M.; Star, A.M.; Alavi, A.

The preoperative diagnosis of the infected orthopedic implant is complicated by lack of a single precise test to forewarn patient and surgeon of the presence of microorganisms. Given the overall limitation of accuracy of preoperative diagnosis to approximately 80% when 111In scanning, preoperative aspiration, and ESR are considered, it would seem prudent to approach each revision surgery with the possibility in mind of subclinical sepsis as the cause for failure of the implant. The essentials of surgical technique including thorough debridement of the wound and removal of all existing foreign bodies, especially including PMMA bone cement, are critical to minimizingmore » the risk for occurrence or persistence of sepsis. Although the use of antibiotic impregnated bone cement may enhance the treatment of orthopedic sepsis, the data available to date lead to the conclusion that two-stage revision surgery in the face of known sepsis remains the cornerstone of surgical therapy for the infected implant, along with aggressive and rational antibiotic treatment. The surgeon is offered the following guidelines in the management of the septic total hip arthroplasty. 1. Preoperative evaluation including ESR, 111In WBC scan, and aspiration for culture and sensitivity (fluoroscopically guided for the hip) will produce on average approximately 80% accuracy. 2. Intraoperative cultures at the time of revision surgery should be obtained prior to administration of systemic antibiotics; three tissue specimens (hip capsule, femoral membrane, acetabular membrane) should be submitted for culture and sensitivity determination. 3. Careful debridement of the surgical site of granulation tissue and all foreign bodies (e.g., PMMA) should be performed within the limits of patient safety to maximize the likelihood of success. 37 refs.« less

The Influence of Cement Morphology Parameters on the Strength of the Cement-Bone Interface in Tibial Tray Fixation.

PubMed

Nagel, Katrin; Bishop, Nicholas E; Schlegel, Ulf J; Püschel, Klaus; Morlock, Michael M

2017-02-01

The strength of the cement-bone interface in tibial component fixation depends on the morphology of the cement mantle. The purpose of this study was to identify thresholds of cement morphology parameters to maximize fixation strength using a minimum amount of cement. Twenty-three cadaveric tibiae were analyzed that had been implanted with tibial trays in previous studies and for which the pull-out strength of the tray had been measured. Specimens were separated into a group failing at the cement-bone interface (INTERFACE) and one failing in the bulk bone (BULK). Maximum pull-out strength corresponds to the ultimate strength of the bulk bone if the cement-bone interface is sufficiently strong. 3D models of the cement mantle in situ were reconstructed from computed tomography scans. The influences of bone mineral density and 6 cement morphology parameters (reflecting cement penetration, bone-cement interface, cement volume) on pull-out strength of the BULK group were determined using multiple regression analysis. The threshold of each parameter for classification of the specimens into either group was determined using receiver operating characteristic analysis. Cement penetration exceeding a mean of 1.1 mm or with a maximum of 5.6 mm exclusively categorized all BULK bone failure specimens. Failure strength of BULK failure specimens increased with bone mineral density (R 2  = 0.67, P < .001) but was independent of the cement morphology parameters. To maximize fixation strength, a mean cement penetration depth of at least 1.1 mm should be achieved during tibial tray cementing. Copyright © 2016 Elsevier Inc. All rights reserved.

Optimization and characterization of a cemented ultimate-storage product

NASA Astrophysics Data System (ADS)

Brunner, H.

1981-12-01

The U- and Pu-containing packaging wastes can be homogeneously cemented after a washing and fragmentation process. Both finely crushed and coarsely fragmented raw wastes yield products with sufficient mechanical stability. The processability limit of the coarsely fragmented raw waste using cement paste or mortar is largely determined by the cellulose content, which is not to exceed 1.3% by weight in the end waste. Of 9 binders studied, the most corrosion-resistant products were obtained with blast-furnace slag cement, whereas poured concrete and Maxit are much less resistant in five-component brine. In the cemented product, hydrolysis of plasticizers (DOP) from plastics (PVC) occurs, leading to release of 2-ethyl-hexanol. This reaction occurs to a much lower degree with blast-furnace slag cement than with all other binders studied. The binder chosen for further tests consists of blast-furnace slag cement, concrete fluidizer and a stabilizer, and is processed at a W/C ratio of 0.43.

Hip morphology predicts posterior hip impingement in a cadaveric model.

PubMed

Morris, William Z; Fowers, Cody A; Weinberg, Douglas S; Millis, Michael B; Tu, Leigh-Anne; Liu, Raymond W

2018-05-01

Posterior hip impingement is a recently-identified cause of hip pain. The purpose of this study is to characterise posterior femoroacetabular and ischiofemoral impingement and identify its predisposing morphologic traits. Two hundred and six cadaveric hips were randomly selected and taken through controlled motion in two pure axes associated with posterior hip impingement: external rotation (through the mechanical axis) and adduction (coronal plane). The range of motion and location of impingement was noted for each specimen. Morphologic traits including femoral/acetabular version, and true neck-shaft angle (TNSA) were also measured. External rotation impingement occurred between the femoral neck and acetabulum in 83.0% of hips, and between the lesser trochanter and ischial tuberosity in 17.0%. Adduction impingement occurred between the lesser trochanter and ischial tuberosity in 78.6% of hips, and between the femoral neck and acetabulum in 21.4%. Multiple regression revealed that increased femoral/acetabular version predicted earlier external rotation and adduction impingement. Unstandardised betas ranging from -0.39 to -0.64 reflect that each degree of increased femoral/acetabular version individually accounts for a loss of external rotation or adduction of approximately half a degree before impingement ( p < 0.001 for each). Increased TNSA was associated with earlier adduction impingement only (unstandardised beta -0.35, p = 0.005). Relative femoral/acetabular anteversion was associated with earlier posterior hip impingement. Coxa valga was associated with earlier adduction impingement, but protective against external rotation impingement. These findings highlight the importance of monitoring correction during femoral/acetabular osteotomies, as overcorrection of retroversion may predispose to earlier posterior impingement.

Relationships among measurements obtained by use of computed tomography and radiography and scores of cartilage microdamage in hip joints with moderate to severe joint laxity of adult dogs.

PubMed

Lopez, Mandi J; Lewis, Brooke P; Swaab, Megan E; Markel, Mark D

2008-03-01

To evaluate correlations among measurements on radiographic and computed tomography (CT) images with articular cartilage microdamage in lax hip joints of dogs. 12 adult mixed-breed hounds. Pelvic CT and radiography were performed. Hip joints were harvested following euthanasia. Orthopedic Foundation for Animals (OFA) and PennHIP radiograph reports were obtained. Norberg angle (NA) and radiographic percentage femoral head coverage (RPC) were determined. Center-edge angle (CEA), horizontal toit externe angle (HTEA), ventral acetabular sector angle (VASA), dorsal acetabular sector angle (DASA), horizontal acetabular sector angle (HASA), acetabular index (AI), and CT percentage femoral head coverage (CPC) were measured on 2-dimensional CT images. Femoral head-acetabular shelf percentage was measured on sagittal 3-dimensional CT (SCT) and transverse 3-dimensional CT (TCT) images. Light microscopy was used to score joint cartilage. Relationships of OFA confirmation and PennHIP osteoarthritis scores with radiography, CT, and cartilage variables and relationships of cartilage scores with radiography and CT measurements were evaluated with Spearman rank correlations. Pearson correlation was used for relationships of distraction index (DI) with radiography, CT, and cartilage variables. Significant relationships included PennHIP osteoarthritis score with cartilage score, CEA, HTEA, DASA, AI, CPC, and TCT; OFA confirmation score with cartilage score, NA, RPC, CEA, HTEA, DASA, AI, CPC, and TCT; cartilage score with NA, RPC, CEA, HTEA, DASA, HASA, AI, and TCT; and DI with cartilage score, CEA, HTEA, DASA, HASA, AI, and CPC. CT appeared to be a valuable imaging modality for predicting cartilage microdamage in canine hip joints.

Early Versus Late Weight-Bearing Protocols for Surgically Managed Posterior Wall Acetabular Fractures.

PubMed

Heare, Austin; Kramer, Nicholas; Salib, Christopher; Mauffrey, Cyril

2017-07-01

Despite overall improved outcomes with open reduction and internal fixation of acetabular fractures, posterior wall fractures show disproportionately poor results. The effect of weight bearing on outcomes of fracture management has been investigated in many lower extremity fractures, but evidence-based recommendations in posterior wall acetabular fractures are lacking. The authors systematically reviewed the current literature to determine if a difference in outcome exists between early and late postoperative weight-bearing protocols for surgically managed posterior wall acetabular fractures. PubMed and MEDLINE were searched for posterior wall acetabular fracture studies that included weight-bearing protocols and Merle d'Aubigné functional scores. Twelve studies were identified. Each study was classified as either early or late weight bearing. Early weight bearing was defined as full, unrestricted weight bearing at or before 12 weeks postoperatively. Late weight bearing was defined as restricted weight bearing for greater than 12 weeks postoperatively. The 2 categories were then compared by functional score using a 2-tailed t test and by complication rate using chi-square analysis. Six studies (152 fractures) were placed in the early weight-bearing category. Six studies (302 fractures) were placed in the late weight-bearing category. No significant difference in Merle d'Aubigné functional scores was found between the 2 groups. No difference was found regarding heterotopic ossification, avascular necrosis, superficial infections, total infections, or osteoarthritis. This systematic review found no difference in functional outcome scores or complication rates between early and late weight-bearing protocols for surgically treated posterior wall fractures. [Orthopedics. 2017: 40(4):e652-e657.]. Copyright 2017, SLACK Incorporated.

Primary stability of a cementless acetabular cup in a cohort of patient-specific finite element models.

PubMed

O'Rourke, Dermot; Al-Dirini, Rami Ma; Taylor, Mark

2018-03-01

The primary stability achieved during total hip arthroplasty determines the long-term success of cementless acetabular cups. Pre-clinical finite element testing of cups typically use a model of a single patient and assume the results can be extrapolated to the general population. This study explored the variability in predicted primary stability of a Pinnacle ® cementless acetabular cup in 103 patient-specific finite element models of the hemipelvis and examined the association between patient-related factors and the observed variability. Cups were inserted by displacement-control into the FE models and then a loading configuration simulating a complete level gait cycle was applied. The cohort showed a range of polar gap of 284-1112 μm and 95th percentile composite peak micromotion (CPM) of 18-624 μm. Regression analysis was not conclusive on the relationship between patient-related factors and primary stability. No relationship was found between polar gap and micromotion. However, when the patient-related factors were categorised into quartile groups, trends suggested higher polar gaps occurred in subjects with small and shallow acetabular geometries and cup motion during gait was affected most by low elastic modulus and high bodyweight. The variation in primary stability in the cohort for an acetabular cup with a proven clinical track record may provide benchmark data when evaluating new cup designs. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1012-1023, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Study of the three-dimensional orientation of the labrum: its relations with the osseous acetabular rim

PubMed Central

Bonneau, Noémie; Bouhallier, July; Baylac, Michel; Tardieu, Christine; Gagey, Olivier

2012-01-01

Understanding the three-dimensional orientation of the coxo-femoral joint remains a challenge as an accurate three-dimensional orientation ensure an efficient bipedal gait and posture. The quantification of the orientation of the acetabulum can be performed using the three-dimensional axis perpendicular to the plane that passes along the edge of the acetabular rim. However, the acetabular rim is not regular as an important indentation in the anterior rim was observed. An innovative cadaver study of the labrum was developed to shed light on the proper quantification of the three-dimensional orientation of the acetabulum. Dissections on 17 non-embalmed corpses were performed. Our results suggest that the acetabular rim is better represented by an anterior plane and a posterior plane rather than a single plane along the entire rim as it is currently assumed. The development of the socket from the Y-shaped cartilage was suggested to explain the different orientations in these anterior and posterior planes. The labrum forms a plane that takes an orientation in between the anterior and posterior parts of the acetabular rim, filling up inequalities of the bony rim. The vectors VL, VA2 and VP, representing the three-dimensional orientation of the labrum, the anterior rim and the posterior rim, are situated in a unique plane that appears biomechanically dependent. The three-dimensional orientation of the acetabulum is a fundamental parameter to understand the hip joint mechanism. Important applications for hip surgery and rehabilitation, as well as for physical anthropology, were discussed. PMID:22360458

Influence of dunite mineral additive on strength of cement

NASA Astrophysics Data System (ADS)

Vasilyeva, A. A.; Moskvitina, L. V.; Moskvitin, S. G.; Lebedev, M. P.; Fedorova, G. D.

2017-12-01

The work studies the applicability of dunite rocks from Inagli massif (South Yakutia) for the production of mixed (composite) cement. The paper reviews the implementation of dunite for manufacturing materials and products. The chemical and mineral compositions of Inagli massif dunite rocks are presented, which relegate the rocks to magnesia-silicate rocks of low-quality in terms of its application as refractory feedstock due to appreciable serpentinization of dunite. The work presents the results of dunite study in terms of its applicability as an additive to Portland cement. The authors have established that dunite does not feature hydraulicity and can be used as a filling additive to Portland cement in the amount of up to 40%. It was unveiled that the mixed grinding of Portland cement and dunite sand with specific surface area of 5500 cm2/g yields the cement that complies with GOST 31108-2016 for CEM II and CEM V normal-cured cements with strength grades of 32.5 and 42.5. The work demonstrates the benefits of the studies of dunite as a filling additive for producing both Portland cement with mineral component and composite (mixed) cement.

A comparative study of indium-111 DTPA radionuclide and iothalamate meglumine roentgenographic arthrography in the evaluation of painful total hip arthroplasty

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maxon, H.R.; Schneider, H.J.; Hopson, C.N.

1989-08-01

Fifteen patients with painful total hip prostheses were referred for nuclear medicine and roentgenographic arthrography studies to exclude loosening of the acetabular and/or the femoral component. A new radioisotopic technique suitable for the evaluation of both components was developed using dual-isotope single-photon tomography with {sup 99m}technetium methylene diphosphonate bone imaging and indium-111 diethylenetriaminepentacetic acid arthrography. Thirteen of the 15 subjects were subsequently treated with additional surgery. The surgical findings were compared with the nuclear medicine and roentgenographic results. The overall diagnostic accuracy of both arthrographic procedures was approximately 80%, but the roentgenographic arthrogram was more sensitive and the radionuclide arthrogrammore » was more specific.« less

Basic considerations for determining the amount of press fit in acetabular cup endoprostheses as a function of the elastic bone behavior.

PubMed

Winter, Werner; Karl, Matthias

2014-10-01

Acetabular cup endoprostheses are frequently placed in pelvic bone, employing the mechanical principle of press fit. While a sufficiently stable bone-implant connection is desirable, deformation of the cup and fracture of the pelvis should be avoided. The goal of this work is to demonstrate the importance of the elastic properties of bone on the amount of press fit achievable in a specific situation. On the basis of previous work describing the relation between relative bone mineral density and relative elastic modulus for cortical and trabecular bone, mechanical equations were used for analyzing the press-fit loading situation of an acetabular cup. Additionally, a two-dimensional finite element model was used for visualizing the stress and strain situation in the host bone occurring as a consequence of implant insertion, as well as the effect of moment loads acting on the acetabular cup. Given the fact that oversizing the implant for a specific recipient site is the only clinical means of optimizing press fit, knowledge of the elastic properties of the host bone before implant selection would be beneficial. Such information could, for instance, be derived from intraoperative compressive testing of the host bone.

Comparable ultrasound measurements of ten anatomical specimens of infant hip joints by the methods of Graf and Terjesen.

PubMed

Falliner, A; Hahne, H J; Hedderich, J; Brossmann, J; Hassenpflug, J

2004-04-01

To define which sonographic section planes relative to the acetabular inlet plane will produce analyzable images with the methods of Graf and Terjesen. Anatomical specimens of infant hip joints were investigated in a water bath using the methods of Graf and Terjesen. Acetabular position was varied in defined increments with respect to the ultrasound beam. The alpha angles and the femoral head coverage (FHC) were measured. To obtain images analyzable by the two methods, the ultrasound beam had to intersect with the acetabular inlet plane at defined angles. The acetabular notch had to be anteriorly rotated from the ultrasound beam plane by at least 20 degrees. Beam entry within a 50 degrees sector posterior to the perpendicular on the inlet plane resulted in analyzable images. The stepwise multiple linear regression analysis showed that alpha angles and FHC were much affected by the coronal-plane transducer tilt. The fact that caudal tilts of the transducer are associated with reduced alpha angles and FHC values should be kept in mind in clinical ultrasound investigations. It is recommended that the transducer should be put on the greater trochanter perpendicular to the transverse axis of the body.

Assessment of acetabular retroversion following long term review of Salter's osteotomy.

PubMed

Robb, Curtis A; Datta, Amit; Nayeemuddin, Mohammed; Bache, Christopher E

2009-01-01

Salter's innominate osteotomy may predispose to anterior over-coverage of the acetabulum. Over cover or retroversion has been demonstrated to be a cause of hip pain, impingement and subsequent osteoarthritis. We reviewed the long-term follow up of seventeen skeletally mature hips in sixteen patients who had previously undergone a Salter's osteotomy in childhood. The Salter pelvic osteotomy was performed at a mean average age of 5 years and follow up at a mean average age of 20 years. Patients were assessed by clinical examination for signs of impingement, Harris Hip Score and pelvic radiograph. Acetabular version was evaluated by the relationship between anterior and posterior walls of the acetabulum using templates applied to the pelvic radiograph as described by Hefti. The median acetabular cover averaged 17 degrees of anteversion with 2 patients (12%) demonstrating retroversion, neither of whom, had signs of impingement on examination. The mean average Harris Hip Score was 85 indicating a good outcome at long-term follow-up. We believe acetabular remodelling may occur with age after Salter's innominate osteotomy and have found good results in patients after skeletal maturation. Fears of long-term anterior over-coverage and retroversion with this operation may be unfounded.

Postural correction reduces hip pain in adult with acetabular dysplasia: A case report.

PubMed

Lewis, Cara L; Khuu, Anne; Marinko, Lee N

2015-06-01

Developmental dysplasia of the hip is often diagnosed in infancy, but less severe cases of acetabular dysplasia are being detected in young active adults. The purpose of this case report is to present a non-surgical intervention for a 31-year-old female with mild acetabular dysplasia and an anterior acetabular labral tear. The patient presented with right anterior hip and groin pain, and she stood with the trunk swayed posterior to the pelvis (swayback posture). The hip pain was reproduced with the anterior impingement test. During gait, the patient maintained the swayback posture and reported 6/10 hip pain. Following correction of the patient's posture, the patient's pain rating was reduced to a 2/10 while walking. The patient was instructed to maintain the improved posture. At the 1 year follow-up, she demonstrated significantly improved posture in standing and walking. She had returned to recreational running and was generally pain-free. The patient demonstrated improvement on self-reported questionnaires for pain, function, and activity. These findings suggest that alteration of posture can have an immediate and lasting effect on hip pain in persons with structural abnormality and labral pathology. Copyright © 2015 Elsevier Ltd. All rights reserved.

Postural correction reduces hip pain in adult with acetabular dysplasia: a case report

PubMed Central

Lewis, Cara L.; Khuu, Anne; Marinko, Lee

2015-01-01

Developmental dysplasia of the hip is often diagnosed in infancy, but less severe cases of acetabular dysplasia are being detected in young active adults. The purpose of this case report is to present a non-surgical intervention for a 31-year-old female with mild acetabular dysplasia and an anterior acetabular labral tear. The patient presented with right anterior hip and groin pain, and she stood with the trunk swayed posterior to the pelvis (swayback posture). The hip pain was reproduced with the anterior impingement test. During gait, the patient maintained the swayback posture and reported 6/10 hip pain. Following correction of the patient’s posture, the patient’s pain rating was reduced to a 2/10 while walking. The patient was instructed to maintain the improved posture. At the 1 year follow-up, she demonstrated significantly improved posture in standing and walking. She had returned to recreational running and was generally pain-free. The patient demonstrated improvement on self-reported questionnaires for pain, function and activity. These findings suggest that alteration of posture can have an immediate and lasting effect on hip pain in persons with structural abnormality and labral pathology. PMID:25731688

Cemented all-polyethylene and metal-backed polyethylene tibial components used for primary total knee arthroplasty: a systematic review of the literature and meta-analysis of randomized controlled trials involving 1798 primary total knee implants.

PubMed

Voigt, Jeffrey; Mosier, Michael

2011-10-05

The cost of the implant as part of a total knee arthroplasty accounts for a substantial portion of the costs for the overall procedure: all-polyethylene tibial components cost considerably less than cemented metal-backed tibial components. We performed a systematic review of the literature to determine whether the clinical results of lower-cost all-polyethylene tibial components were comparable with the results of a more expensive metal-backed tibial component. We searched The Cochrane Library, MEDLINE, EMBASE, EBSCO CINAHL, the bibliographies of identified articles, orthopaedic meeting abstracts, health technology assessment web sites, and important orthopaedic journals. This search was performed for the years 1990 to the present. No language restriction was applied. We restricted our search to Level-I studies involving participants who received either an all-polyethylene or a metal-backed tibial implant. The primary outcome measures were durability, function, and adverse events. Two reviewers independently screened the papers for inclusion, assessed trial quality, and extracted data. Effects estimates were pooled with use of fixed and random-effects models of risk ratios, calculated with 95% confidence intervals. Heterogeneity was assessed with the I2 statistic. Forest plots were also generated. Data on 1798 primary total knee implants from twelve studies were analyzed. In all studies, the median or mean age of the participants was greater than sixty-seven years, with a majority of the patients being female. There was no difference between patients managed with an all-polyethylene tibial component and those managed with a metal-backed tibial component in terms of adverse events. There was no significant difference between the two groups in terms of the durability of the implants at two, ten, and fifteen years postoperatively, regardless of the year or how durability was defined (revision or radiographic failure). Finally, with use of a variety of validated measures, there was no difference between the two groups in terms of functional status at two, eight, and ten years, regardless of the measure used. A less expensive all-polyethylene component as part of a total knee arthroplasty has results equivalent to those obtained with a cemented metal-backed tibial component. Using a total knee implant with a cemented all-polyethylene tibial component could save the healthcare system substantial money while obtaining equivalent results to more expensive cemented designs and materials.

Relationship between operational variables, fundamental physics and foamed cement properties in lab and field generated foamed cement slurries

DOE PAGES

Glosser, D.; Kutchko, B.; Benge, G.; ...

2016-03-21

Foamed cement is a critical component for wellbore stability. The mechanical performance of a foamed cement depends on its microstructure, which in turn depends on the preparation method and attendant operational variables. Determination of cement stability for field use is based on laboratory testing protocols governed by API Recommended Practice 10B-4 (API RP 10B-4, 2015). However, laboratory and field operational variables contrast considerably in terms of scale, as well as slurry mixing and foaming processes. Here in this paper, laboratory and field operational processes are characterized within a physics-based framework. It is shown that the “atomization energy” imparted by themore » high pressure injection of nitrogen gas into the field mixed foamed cement slurry is – by a significant margin – the highest energy process, and has a major impact on the void system in the cement slurry. There is no analog for this high energy exchange in current laboratory cement preparation and testing protocols. Quantifying the energy exchanges across the laboratory and field processes provides a basis for understanding relative impacts of these variables on cement structure, and can ultimately lead to the development of practices to improve cement testing and performance.« less

21 CFR 888.3480 - Knee joint femorotibial metallic constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metallic constrained... Knee joint femorotibial metallic constrained cemented prosthesis. (a) Identification. A knee joint... knee joint. The device prevents dislocation in more than one anatomic plane and has components that are...

The influence of stem length and fixation on initial femoral component stability in revision total knee replacement

PubMed Central

Conlisk, N.; Gray, H.; Pankaj, P.; Howie, C. R.

2012-01-01

Objectives Orthopaedic surgeons use stems in revision knee surgery to obtain stability when metaphyseal bone is missing. No consensus exists regarding stem size or method of fixation. This in vitro study investigated the influence of stem length and method of fixation on the pattern and level of relative motion at the bone–implant interface at a range of functional flexion angles. Methods A custom test rig using differential variable reluctance transducers (DVRTs) was developed to record all translational and rotational motions at the bone–implant interface. Composite femurs were used. These were secured to permit variation in flexion angle from 0° to 90°. Cyclic loads were applied through a tibial component based on three peaks corresponding to 0°, 10° and 20° flexion from a normal walking cycle. Three different femoral components were investigated in this study for cementless and cemented interface conditions. Results Relative motions were found to increase with flexion angle. Stemmed implants reduced relative motions in comparison to stemless implants for uncemented constructs. Relative motions for cemented implants were reduced to one-third of their equivalent uncemented constructs. Conclusions Stems are not necessary for cemented implants when the metaphyseal bone is intact. Short cemented femoral stems confer as much stability as long uncemented stems. PMID:23610659

Research of cost aspects of cement pavements construction

NASA Astrophysics Data System (ADS)

Bezuglyi, Artem; Illiash, Sergii; Tymoshchuk, Oleksandr

2017-09-01

The tendency to increasing traffic volume on public roads and to increased axle loads of vehicles makes the road scientists to develop scientifically justified methods for preserving the existing and developing the new transport network of Ukraine. One of the options for solving such issues is the construction of roads with rigid (cement concrete) pavement. However, any solution must be justified considering technical and economic components. This paper presents the results of the research of cost aspects of cement pavements construction.

Minimally invasive and computer-navigated total hip arthroplasty: a qualitative and systematic review of the literature

PubMed Central

2010-01-01

Background Both minimally invasive surgery (MIS) and computer-assisted surgery (CAS) for total hip arthroplasty (THA) have gained popularity in recent years. We conducted a qualitative and systematic review to assess the effectiveness of MIS, CAS and computer-assisted MIS for THA. Methods An extensive computerised literature search of PubMed, Medline, Embase and OVIDSP was conducted. Both randomised clinical trials and controlled clinical trials on the effectiveness of MIS, CAS and computer-assisted MIS for THA were included. Methodological quality was independently assessed by two reviewers. Effect estimates were calculated and a best-evidence synthesis was performed. Results Four high-quality and 14 medium-quality studies with MIS THA as study contrast, and three high-quality and four medium-quality studies with CAS THA as study contrast were included. No studies with computer-assisted MIS for THA as study contrast were identified. Strong evidence was found for a decrease in operative time and intraoperative blood loss for MIS THA, with no difference in complication rates and risk for acetabular outliers. Strong evidence exists that there is no difference in physical functioning, measured either by questionnaires or by gait analysis. Moderate evidence was found for a shorter length of hospital stay after MIS THA. Conflicting evidence was found for a positive effect of MIS THA on pain in the early postoperative period, but that effect diminished after three months postoperatively. Strong evidence was found for an increase in operative time for CAS THA, and limited evidence was found for a decrease in intraoperative blood loss. Furthermore, strong evidence was found for no difference in complication rates, as well as for a significantly lower risk for acetabular outliers. Conclusions The results indicate that MIS THA is a safe surgical procedure, without increases in operative time, blood loss, operative complication rates and component malposition rates. However, the beneficial effect of MIS THA on functional recovery has to be proven. The results also indicate that CAS THA, though resulting in an increase in operative time, may have a positive effect on operative blood loss and operative complication rates. More importantly, the use of CAS results in better positioning of acetabular component of the prosthesis. PMID:20470443

Bilateral non-traumatic acetabular and femoral neck fractures due to pregnancy-associated osteoporosis.

PubMed

Aynaci, Osman; Kerimoglu, Servet; Ozturk, Cagatay; Saracoglu, Metehan

2008-03-01

Pregnancy-associated osteoporosis is a rare disorder and its pathophysiology remains unknown. We report a case of pregnancy-associated osteoporosis in a 27-year-old primiparous patient who revealed bilateral hip pain during early postnatal period. The plain radiographs and computerized tomography showed bilateral femoral neck and acetabular fractures. The diagnosis of osteoporosis was established by bone mineral density. Diagnostic work-up excluded a secondary osteoporosis. The case was treated successfully by bilateral cementless total hip arthroplasty. Bone mineral density increased after 2 years of treatment with calcium-vitamin D, calcitriol and alendronate. Diagnosis of pregnancy-associated osteoporosis should be suspected when hip pain occurs during pregnancy or in the post-partum period as it can lead to acetabular and femoral neck fractures.

Optimisation of a two-liquid component pre-filled acrylic bone cement system: a design of experiments approach to optimise cement final properties.

PubMed

Clements, James; Walker, Gavin; Pentlavalli, Sreekanth; Dunne, Nicholas

2014-10-01

The initial composition of acrylic bone cement along with the mixing and delivery technique used can influence its final properties and therefore its clinical success in vivo. The polymerisation of acrylic bone cement is complex with a number of processes happening simultaneously. Acrylic bone cement mixing and delivery systems have undergone several design changes in their advancement, although the cement constituents themselves have remained unchanged since they were first used. This study was conducted to determine the factors that had the greatest effect on the final properties of acrylic bone cement using a pre-filled bone cement mixing and delivery system. A design of experiments (DoE) approach was used to determine the impact of the factors associated with this mixing and delivery method on the final properties of the cement produced. The DoE illustrated that all factors present within this study had a significant impact on the final properties of the cement. An optimum cement composition was hypothesised and tested. This optimum recipe produced cement with final mechanical and thermal properties within the clinical guidelines and stated by ISO 5833 (International Standard Organisation (ISO), International standard 5833: implants for surgery-acrylic resin cements, 2002), however the low setting times observed would not be clinically viable and could result in complications during the surgical technique. As a result further development would be required to improve the setting time of the cement in order for it to be deemed suitable for use in total joint replacement surgery.

Is there a rationale to use a dual mobility poly insert for failed Birmingham metal-on-metal hip replacements? A retrieval analysis.

PubMed

Renner, Lisa; Faschingbauer, Martin; Boettner, Friedrich

2015-08-01

Previous studies showed poor outcomes for patients undergoing revision of failed metal-on-metal total hip arthroplasty (MoM-THA) and resurfacing (RS) with an increased risk of dislocation. Dual mobility inserts are an option to retain the acetabular component and change the metal-on-metal bearing to plastic-on-metal. The current study analyzes the rationale for the off-label use of a dual mobility poly insert (MDM X3, Stryker, Mahwah, NJ) in a Birmingham metal shell (Smith & Nephew, Memphis, TN). Based on retrievals from the implant database the study compared the clearance between 20 BHR shells, 31 MDM poly inserts and 24 ADM acetabular components of different sizes. The radial clearance was calculated for each possible combination of implants [n = 81 (MDM/BHR) and n = 119 (MDM/ADM)]. An MDM mobile bearing poly insert in an ADM shell has an average clearance of 0.314 mm (SD 0.031) compared to 0.234 mm (SD 0.030) in a BHR shell (p < 0.01). The minimal clearance is 0.246 and 0.163 mm, respectively. 30.9 % of the MDM/BHR clearances were within the range of the MDM/ADM bearing and 88.9 % had a clearance of more than 0.2 mm. Clearances of the MDM poly insert in a BHR shell are reduced, and although the majority of combinations appear safe, the indication needs to be made on an individual base carefully considering alternative treatment options.

Mechanisms of plastic deformation in highly cross-linked UHMWPE for total hip components--the molecular physics viewpoint.

PubMed

Takahashi, Yasuhito; Shishido, Takaaki; Yamamoto, Kengo; Masaoka, Toshinori; Kubo, Kosuke; Tateiwa, Toshiyuki; Pezzotti, Giuseppe

2015-02-01

Plastic deformation is an unavoidable event in biomedical polymeric implants for load-bearing application during long-term in-vivo service life, which involves a mass transfer process, irreversible chain motion, and molecular reorganization. Deformation-induced microstructural alterations greatly affect mechanical properties and durability of implant devices. The present research focused on evaluating, from a molecular physics viewpoint, the impact of externally applied strain (or stress) in ultra-high molecular weight polyethylene (UHMWPE) prostheses, subjected to radiation cross-linking and subsequent remelting for application in total hip arthroplasty (THA). Two different types of commercial acetabular liners, which belong to the first-generation highly cross-linked UHMWPE (HXLPE), were investigated by means of confocal/polarized Raman microprobe spectroscopy. The amount of crystalline region and the spatial distribution of molecular chain orientation were quantitatively analyzed according to a combined theory including Raman selection rules for the polyethylene orthorhombic structure and the orientation distribution function (ODF) statistical approach. The structurally important finding was that pronounced recrystallization and molecular reorientation increasingly appeared in the near-surface regions of HXLPE liners with increasing the amount of plastic (compressive) deformation stored in the microstructure. Such molecular rearrangements, occurred in response to external strains, locally increase surface cross-shear (CS) stresses, which in turn trigger microscopic wear processes in HXLPE acetabular liners. Thus, on the basis of the results obtained at the molecular scale, we emphasize here the importance of minimizing the development of irrecoverable deformation strain in order to retain the pristine and intrinsically high wear performance of HXLPE components. Copyright © 2014 Elsevier Ltd. All rights reserved.

Retention System and Splinting on Morse Taper Implants in the Posterior Maxilla by 3D Finite Element Analysis.

PubMed

Lemos, Cleidiel Aparecido Araujo; Verri, Fellippo Ramos; Santiago, Joel Ferreira; Almeida, Daniel Augusto de Faria; Batista, Victor Eduardo de Souza; Noritomi, Pedro Yoshito; Pellizzer, Duardo Piza

2018-01-01

The purpose of this study was to evaluate different retention systems (cement- or screw-retained) and crown designs (non-splinted or splinted) of fixed implant-supported restorations, in terms of stress distributions in implants/components and bone tissue, by 3-dimensional (3D) finite element analysis. Four 3D models were simulated with the InVesalius, Rhinoceros 3D, and SolidWorks programs. Models were made of type III bone from the posterior maxillary area. Models included three 4.0-mm-diameter Morse taper (MT) implants with different lengths, which supported metal-ceramic crowns. Models were processed by the Femap and NeiNastran programs, using an axial force of 400 N and oblique force of 200 N. Results were visualized as the von Mises stress and maximum principal stress (σmax). Under axial loading, there was no difference in the distribution of stress in implants/components between retention systems and splinted crowns; however, in oblique loading, cemented prostheses showed better stress distribution than screwed prostheses, whereas splinted crowns tended to reduce stress in the implant of the first molar. In the bone tissue cemented prostheses showed better stress distribution in bone tissue than screwed prostheses under axial and oblique loading. The splinted design only had an effect in the screwed prosthesis, with no influence in the cemented prosthesis. Cemented prostheses on MT implants showed more favorable stress distributions in implants/components and bone tissue. Splinting was favorable for stress distribution only for screwed prostheses under oblique loading.

The Safe Zone Range for Cup Anteversion Is Narrower Than for Inclination in THA.

PubMed

Murphy, William S; Yun, Ho Hyun; Hayden, Brett; Kowal, Jens H; Murphy, Stephen B

2018-02-01

Cup malposition is a common cause of impingement, limitation of ROM, acceleration of bearing wear, liner fracture, and instability in THA. Previous studies of the safe zone based on plain radiographs have limitations inherent to measuring angles from two-dimensional projections. The current study uses CT to measure component position in stable and unstable hips to assess the presence of a safe zone for cup position in THA. (1) Does acetabular component orientation, when measured on CT, differ in stable components and those revised for recurrent instability? (2) Do CT data support historic safe zone definitions for component orientation in THA? We identified 34 hips that had undergone revision of the acetabulum for recurrent instability that also had a CT scan of the pelvis between August 2003 and February 2017. We also identified 175 patients with stable hip replacements who also had a CT study for preoperative planning and intraoperative navigation of the contralateral side. For each CT study, one observer analyzed major factors including acetabular orientation, femoral anteversion, combined anteversion (the sum of femoral and anatomic anteversion), pelvic tilt, total offset difference, head diameter, age, sex, and body mass index. These measures were then compared among stable hips, hips with cup revision for anterior instability, and hips with cup revision for posterior instability. We used a clinically relevant measurement of operative anteversion and inclination as opposed to the historic use of radiographic anteversion and inclination. The percentage of unstable hips in the historic Lewinnek safe zone was calculated, and a new safe zone was proposed based on an area with no unstable hips. Anteriorly unstable hips compared with stable hips had higher operative anteversion of the cup (44° ± 12° versus 31° ± 11°, respectively; mean difference, 13°; 95% confidence interval [CI], 5°-21°; p = 0.003), tilt-adjusted operative anteversion of the cup (40° ± 6° versus 26° ± 10°, respectively; mean difference, 14°; 95% CI, 10°-18°; p < 0.001), and combined tilt-adjusted anteversion of the cup (64° ± 10° versus 54° ± 19°, respectively; mean difference, 10°; 95% CI, 1°-19°; p = 0.028). Posteriorly unstable hips compared with stable hips had lower operative anteversion of the cup (19° ± 15° versus 31° ± 11°, respectively; mean difference, -12°; 95% CI, -5° to -18°; p = 0.001), tilt-adjusted operative anteversion of the cup (19° ± 13° versus 26° ± 10°, respectively; mean difference, -8°; 95% CI, -14° to -2°; p = 0.014), pelvic tilt (0° ± 6° versus 4° ± 6°, respectively; mean difference, -4°; 95% CI, -7° to -1°; p = 0.007), and anatomic cup anteversion (25° ± 18° versus 34° ± 12°, respectively; mean difference, -9°; 95% CI, -1° to -17°; p = 0.033). Thirty-two percent of the unstable hips were located in the Lewinnek safe zone (11 of 34; 10 posterior dislocations, one anterior dislocation). In addition, a safe zone with no unstable hips was identified within 43° ± 12° of operative inclination and 31° ± 8° of tilt-adjusted operative anteversion. The current study supports the notion of a safe zone for acetabular component orientation based on CT. However, the results demonstrate that the historic Lewinnek safe zone is not a reliable predictor of future stability. Analysis of tilt-adjusted operative anteversion and operative inclination demonstrates a new safe zone where no hips were revised for recurrent instability that is narrower for tilt-adjusted operative anteversion than for operative inclination. Tilt-adjusted operative anteversion is significantly different between stable and unstable hips, and surgeons should therefore prioritize assessment of preoperative pelvic tilt and accurate placement in operative anteversion. With improvements in patient-specific cup orientation goals and acetabular component placement, further refinement of a safe zone with CT data may reduce the incidence of cup malposition and its associated complications. Level III, diagnostic study.

3D surgical printing and pre contoured plates for acetabular fractures.

PubMed

Chana-Rodríguez, Francisco; Mañanes, Rubén Pérez; Rojo-Manaute, José; Gil, Pablo; Martínez-Gómiz, José María; Vaquero-Martín, Javier

2016-11-01

We describe the methodical and possibilities of 3D surgical printing in preoperative planning of acetabular fractures showing a case of a 45-year-old with an associated transverse fracture of the left acetabulum with posterior wall fracture, with multiple fragments, and posterior ipsilateral hip dislocation, defending the do it your-self mode. Copyright © 2016 Elsevier Ltd. All rights reserved.

Augmented wedge-shaped glenoid component for the correction of glenoid retroversion: a finite element analysis.

PubMed

Hermida, Juan C; Flores-Hernandez, Cesar; Hoenecke, Heinz R; D'Lima, Darryl D

2014-03-01

This study undertook a computational analysis of a wedged glenoid component for correction of retroverted glenoid arthritic deformity to determine whether a wedge-shaped glenoid component design with a built-in correction for version reduces excessive stresses in the implant, cement, and glenoid bone. Recommendations for correcting retroversion deformity are asymmetric reaming of the anterior glenoid, bone grafting of the posterior glenoid, or a glenoid component with posterior augmentation. Eccentric reaming has the disadvantages of removing normal bone, reducing structural support for the glenoid component, and increasing the risk of bone perforation by the fixation pegs. Bone grafting to correct retroverted deformity does not consistently generate successful results. Finite element models of 2 scapulae models representing a normal and an arthritic retroverted glenoid were implanted with a standard glenoid component (in retroversion or neutral alignment) or a wedged component. Glenohumeral forces representing in vivo loading were applied and stresses and strains computed in the bone, cement, and glenoid component. The retroverted glenoid components generated the highest compressive stresses and decreased cyclic fatigue life predictions for trabecular bone. Correction of retroversion by the wedged glenoid component significantly decreased stresses and predicted greater bone fatigue life. The cement volume estimated to survive 10 million cycles was the lowest for the retroverted components and the highest for neutrally implanted glenoid components and for wedged components. A wedged glenoid implant is a viable option to correct severe arthritic retroversion, reducing the need for eccentric reaming and the risk for implant failure. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Long-term retrospective study on the placement of the cementless acetabular cup and clinical outcomes in patients undergoing femoral head autografting for hip dysplasia and total hip arthroplasty.

PubMed

Ozden, Vahit Emre; Dikmen, Goksel; Beksac, Burak; Tozun, Ismail Remzi

2018-05-01

Placement of acetabular cup in the dysplastic hip is a challenging procedure. Using bulk femoral head autograft to increase the bony coverage of the cup is one of the techniques, which have been described. The impact of cup position on cup and autograft survival is a controversial issue. We aimed to determine whether the position of cementless acetabular cup used in conjunction with femoral head autograft in dysplastic hips affected the autograft-host incorporation with its final radiographic appearance and the cup survivorship into the second decade. Thirty-eight dysplastic hips with varying Crowe types in 31 patients (30 women and one man) were included. The mean age was 47 years (range, 29-64 years) and the mean follow-up was 20.3 years (range, 14.8-25.9 years). The initial postoperative and final radiographs were evaluated. The survival rate of the cups was analysed using Kaplan-Meier statistics and the log-rank test. Multivariate analysis was used to evaluate the effect of variables (Crowe type, radiographic initial host bone coverage over the cup and position of the cup) on survivorship. The acetabular cups were positioned anatomical in 27/38 hips according to Ranawat measurement technique. Trabecular bridging at graft-host interface was seen in all cases at an average 22.1 months. Neither acetabular cup position nor initial host bone coverage over acetabular cup less than 50% had any significant effect on either cup survival or final radiographic appearance of the graft. The 20-year cup survival rate without aseptic revision was 66% (95 CI, 52%-84%). No revision was performed due to graft resorption. Twenty-year survival rate of the cementless cup combination with femoral head autograft showed no significant differences whether it was placed at high or anatomic hip centre. The final radiographic appearance of the autograft was not affected from either the cup location or the initial radiographic horizontal host bone coverage. Copyright © 2018 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Bony morphology of the hip in professional ballet dancers compared to athletes.

PubMed

Mayes, Susan; Ferris, April-Rose; Smith, Peter; Garnham, Andrew; Cook, Jill

2017-07-01

To compare hip bony morphology between ballet dancers and a sporting control group and to determine the relationship with hip pain. Thirty-three professional ballet dancers and 33 age- and sex-matched athletes completed questionnaires, including the Copenhagen Hip and Groin Outcome Score (HAGOS), and underwent clinical testing and 3.0-T magnetic resonance imaging to measure acetabular coverage with lateral centre edge angles, femoral head-neck junction concavity with alpha angles at anterior and superior positions, femoral neck-shaft angles, and acetabular version angles. Bony morphological measures fell within normal ranges. Dancers had higher neck-shaft angles (dancers 134.6 ± 4.6°/athletes130.8 ± 4.7°, p = 0.002), lower acetabular version angles (13.5 ± 4.7°/17.1 ± 4.7°, p = 0.003), lower superior alpha angles (38.9 ± 6.9°/46.7 ± 10.6°, p < 0.001), similar anterior alpha angles (43.6 ± 8.1/46 ± 7°, p = 0.2), and similar lateral centre edge angles (28.8 ± 4.6°/30.8 ± 4.5°, p = 0.07) compared to athletes. Abnormal morphology was detected in dancers: 3% acetabular dysplasia (athletes 0), 15% borderline dysplasia (6%), 24% cam morphology (33%), 24% coxa valga (6%), and 21% acetabular retroversion (18%). The HAGOS pain scores correlated moderately with acetabular version (r = -0.43, p = 0.02) in dancers, with no other correlation between pain and morphological parameters in either group. Professional ballet dancers have hip bony morphology that differentiates them from athletes. Hip pain correlated poorly with bony morphology. • Ballet dancers have hip bony morphology that may allow extreme hip motion. • Morphological parameter means fell within normal reference intervals in dancers. • Bony morphology correlates poorly with hip pain. • The risk of hip injury due to abnormal morphology requires prospective studies.

Process for disposal of aqueous solutions containing radioactive isotopes

DOEpatents

Colombo, Peter; Neilson, Jr., Robert M.; Becker, Walter W.

1979-01-01

A process for disposing of radioactive aqueous waste solutions whereby the waste solution is utilized as the water of hydration to hydrate densified powdered portland cement in a leakproof container; said waste solution being dispersed without mechanical inter-mixing in situ in said bulk cement, thereafter the hydrated cement body is impregnated with a mixture of a monomer and polymerization catalyst to form polymer throughout the cement body. The entire process being carried out while maintaining the temperature of the components during the process at a temperature below 99.degree. C. The container containing the solid polymer-impregnated body is thereafter stored at a radioactive waste storage dump such as an underground storage dump.

Cement Finishing. Pre-Apprenticeship Phase 2 Training. Instructor's Guide.

ERIC Educational Resources Information Center

Nama, Joe

This instructor's guide accompanies the self-paced student training modules on cement finishing, available separately as CE 031 576. Introductory materials include a description of the components of the pre-apprenticeship project, discussion of teacher's role in students' completion of the modules, and scope and contents of Phase 2 training. Each…

T2* Mapping Provides Information That Is Statistically Comparable to an Arthroscopic Evaluation of Acetabular Cartilage.

PubMed

Morgan, Patrick; Nissi, Mikko J; Hughes, John; Mortazavi, Shabnam; Ellerman, Jutta

2017-07-01

Objectives The purpose of this study was to validate T2* mapping as an objective, noninvasive method for the prediction of acetabular cartilage damage. Methods This is the second step in the validation of T2*. In a previous study, we established a quantitative predictive model for identifying and grading acetabular cartilage damage. In this study, the model was applied to a second cohort of 27 consecutive hips to validate the model. A clinical 3.0-T imaging protocol with T2* mapping was used. Acetabular regions of interest (ROI) were identified on magnetic resonance and graded using the previously established model. Each ROI was then graded in a blinded fashion by arthroscopy. Accurate surgical location of ROIs was facilitated with a 2-dimensional map projection of the acetabulum. A total of 459 ROIs were studied. Results When T2* mapping and arthroscopic assessment were compared, 82% of ROIs were within 1 Beck group (of a total 6 possible) and 32% of ROIs were classified identically. Disease prediction based on receiver operating characteristic curve analysis demonstrated a sensitivity of 0.713 and a specificity of 0.804. Model stability evaluation required no significant changes to the predictive model produced in the initial study. Conclusions These results validate that T2* mapping provides statistically comparable information regarding acetabular cartilage when compared to arthroscopy. In contrast to arthroscopy, T2* mapping is quantitative, noninvasive, and can be used in follow-up. Unlike research quantitative magnetic resonance protocols, T2* takes little time and does not require a contrast agent. This may facilitate its use in the clinical sphere.

Direct and indirect costs of surgically treated pelvic fractures.

PubMed

Aprato, Alessandro; Joeris, Alexander; Tosto, Ferdinando; Kalampoki, Vasiliki; Stucchi, Alessandro; Massè, Alessandro

2016-03-01

Pelvic fractures requiring surgical fixation are rare injuries but present a great societal impact in terms of disability, as well as economic resources. In the literature, there is no description of these costs. Main aim of this study is to describe the direct and indirect costs of these fractures. Secondary aims were to test if the type of fracture (pelvic ring injury or acetabular fracture) influences these costs (hospitalization, consultation, medication, physiotherapy sessions, job absenteeism). We performed a retrospective study on patients with surgically treated acetabular fractures or pelvic ring injuries. Medical records were reviewed in terms of demographic data, follow-up, diagnosis (according to Letournel and Tile classifications for acetabular and pelvic fractures, respectively) and type of surgical treatment. Patients were interviewed about hospitalization length, consultations after discharge, medications, physiotherapy sessions and absenteeism. The study comprised 203 patients, with a mean age of 49.1 ± 15.6 years, who had undergone surgery for an acetabular fracture or pelvic ring injury. The median treatment costs were 29.425 Euros per patient. Sixty percent of the total costs were attributed to health-related work absence. Median costs (in Euros) were 2.767 for hospitalization from trauma to definitive surgery, 4.530 for surgery, 3.018 for hospitalization in the surgical unit, 1.693 for hospitalization in the rehabilitation unit, 1.920 for physiotherapy after discharge and 402 for consultations after discharge. Total costs for treating pelvic ring injuries were higher than for acetabular fractures, mainly due to the significant higher costs of pelvic injuries regarding hospitalization from trauma to definitive surgery (p < 0.001) and hospitalization in the surgical unit (p = 0.008). Pelvic fractures are associated with both high direct costs and substantial productivity loss.

Application of an innovative computerized virtual planning system in acetabular fracture surgery: A feasibility study.

PubMed

Wang, Huixiang; Wang, Fang; Newman, Simon; Lin, Yanping; Chen, Xiaojun; Xu, Lu; Wang, Qiugen

2016-08-01

Acetabular fracture surgery is amongst the most challenging tasks in the field of trauma surgery and careful preoperative planning is crucial for success. The aim of this paper is to describe the preliminary outcome of the utilization of an innovative computerized virtual planning system for acetabular fractures. 3D models of acetabular fractures and surrounding soft tissues from six patients were constructed from preoperative CT scans. A novel highly-automatic segmentation technique was performed on the 3D model to separate each fracture fragment, then 3D virtual reduction was performed. Additionally, the models were used to assess potential surgical approaches with reference to both the fracture and the surrounding soft tissues. The time required for virtual planning was recorded. After surgery, the virtual plan was compared to the real surgery with respect to surgical approach and reduction sequence. A Likert scale questionnaire was completed by the surgeons to evaluate their satisfaction with the system. Virtual planning was successfully completed in all cases. The planned surgical approach was followed in all cases with the planned reduction sequence followed completely in five cases and partially in one. The mean time required for virtual planning was 38.7min (range 21-57, SD=15.5). The mean time required for planning of B-type fractures was 25.0min (range 21-30, SD=4.6), of C-type fracture 52.3min (range 49-57, SD=4.2). The results of the questionnaire demonstrated a high level of satisfaction with the planning system. This study demonstrates that the virtual planning system is feasible in clinical settings with high satisfaction and acceptability from the surgeons. It provides a viable option for the planning of acetabular fracture surgery. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparative study of comminuted posterior acetabular wall fracture treated with the Acetabular Tridimensional Memory Fixation System.

PubMed

Zhang, Yuntong; Zhao, Xue; Tang, Yang; Zhang, Chuncai; Xu, Shuogui; Xie, Yang

2014-04-01

Posterior wall fractures are one of the most common acetabular fractures. However, only 30% of these fractures involve a single large fragment, and comminuted acetabular posterior wall fractures pose a particular surgical challenge. The purpose of this study was to compare outcomes between patients who received fixation for comminuted posterior wall fracture using the Acetabular Tridimensional Memory Fixation System (ATMFS) and patients who underwent fixation with conventional screws and buttress plates (Plates group). Between April 2003 and May 2007, 196 consecutive patients who sustained a comminuted posterior wall fracture of acetabulum were treated with ATMFS or conventional screws and buttress plates. Operative time, fluoroscopy time, blood loss, and any intra-operative complications were recorded. Plain AP and lateral radiographs were obtained at all visits (Matta's criteria). Modified Merle d' Aubigne-Postel score, and Mos SF-36 score were compared between groups. Fifty patients were included in the analysis with 26 in the ATMFS group and 24 in the Plates group. The mean follow-up time was 57.5 months, ranging from 31 to 69 months. All patients had fully healed fractures at the final follow-up. There was no difference in clinical outcomes or radiological evaluations between groups. Patients with comminuted posterior wall fractures of the acetabulum treated with the ATMFS or conventional screws and buttress plate techniques achieve a good surgical result. Both techniques are safe, reliable, and practical. Use of the ATMFS technique may reduce blood loss and improve rigid support to marginal bone impaction. The use ATMFS may need additional support when fractures involve the superior roof. Copyright © 2013 Elsevier Ltd. All rights reserved.

Morphometric analysis of acetabular dysplasia in cerebral palsy: three-dimensional CT study.

PubMed

Gose, Shinichi; Sakai, Takashi; Shibata, Toru; Murase, Tsuyoshi; Yoshikawa, Hideki; Sugamoto, Kazuomi

2009-12-01

Three-dimensional computed tomography (3D-CT) eliminates the positioning errors and allows the clinician to more accurately assess the radiographic parameters present. To elucidate the 3D geometry of the acetabulum and the extent of hip subluxation/dislocation in patients with cerebral palsy (CP), quantitative morphometric analysis was performed using 3D-CT data. We evaluated 150 hips in 75 patients with bilateral spastic CP. The mean age of the patients was 5.4 years (range: 2.7 to 6.9 y). The fitting plane of the ilium was projected onto the coronal plane and then onto the sagittal plane, and then the angle formed with a horizontal line was defined as CTalpha (the lateral opening angle) and CTbeta (the sagittal inclination angle), respectively. The center of the acetabulum and the femoral head were defined, and the distance between these centers was divided by the femoral head diameter, defined as CT migration percentage (CTMP, %). In 123 (82%) of the 150 hips, the femoral head center was located posteriorly, superiorly, and laterally relative to the acetabular center. Large CTalpha cases tended to show large CTMP. CTalpha and CTMP were significantly larger in the cases with Gross Motor Functional Classification System (GMFCS) level IV/V and spastic quadriplegia, than in the cases with GMFCS level II/III and spastic diplegia. CTbeta showed significant correlation with the acetabular defect on the lateral 3D reconstructed images. Three-dimensional acetabular geometry and migration percentage in CP patients can be analyzed quantitatively using 3D-CT regardless of the abnormal spastic posture. The extent of acetabular dysplasia and subluxation is more severe in patients with GMFCS level IV/V and spastic quadriplesia. Level 4.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glosser, D.; Kutchko, B.; Benge, G.

Foamed cement is a critical component for wellbore stability. The mechanical performance of a foamed cement depends on its microstructure, which in turn depends on the preparation method and attendant operational variables. Determination of cement stability for field use is based on laboratory testing protocols governed by API Recommended Practice 10B-4 (API RP 10B-4, 2015). However, laboratory and field operational variables contrast considerably in terms of scale, as well as slurry mixing and foaming processes. Here in this paper, laboratory and field operational processes are characterized within a physics-based framework. It is shown that the “atomization energy” imparted by themore » high pressure injection of nitrogen gas into the field mixed foamed cement slurry is – by a significant margin – the highest energy process, and has a major impact on the void system in the cement slurry. There is no analog for this high energy exchange in current laboratory cement preparation and testing protocols. Quantifying the energy exchanges across the laboratory and field processes provides a basis for understanding relative impacts of these variables on cement structure, and can ultimately lead to the development of practices to improve cement testing and performance.« less

Influence of Cellulosic Fibres on the Physical Properties of Fibre Cement Composites

NASA Astrophysics Data System (ADS)

Hospodarova, V.; Stevulova, N.; Vaclavik, V.; Dvorsky, T.

2017-10-01

Nowadays, there are new approaches directing to processing of non-conventional fibre-cement composites for application in the housing construction. Vegetable cellulosic fibres coming from natural resources used as reinforcement in cost-effective and environmental friendly building products are in the spotlight. The applying of natural fibres in cement based composites is narrowly linked to the ecological building sector, where a choice of materials is based on components including recyclable, renewable raw materials and low-resource manufacture techniques. In this paper, two types of cellulosic fibres coming from wood pulp and recycled waste paper with 0.2%; 0.3% and 0.5% of fibre addition into cement mixtures were used. Differences in the physical characteristics (flowability, density, coefficient of thermal conductivity and water absorbability) of 28 days hardened fibre-cement composites are investigated. Addition of cellulosic fibres to cement mixture caused worsening the workability of fresh mixture as well as absorbability of hardened composites due to hydrophilic nature of biomaterial, whereas density and thermal conductivity of manufactured cement based fibre plaster are enhanced. The physical properties of cement plasters based on cellulosic fibres depend on structural, physical characteristics of cellulosic fibres, their nature and processing.

The mechanical response of a polyetheretherketone femoral knee implant under a deep squatting loading condition.

PubMed

de Ruiter, Lennert; Janssen, Dennis; Briscoe, Adam; Verdonschot, Nico

2017-12-01

The current study was designed to investigate the mechanical response of a polyetheretherketone-on-polyethylene total knee replacement device during a deep squat. Application of this high-demand loading condition can identify weaknesses of the polyetheretherketone relative to cobalt-chromium. This study investigated whether the implant is strong enough for this type of loading, whether cement stresses are considerably changed and whether a polyetheretherketone femoral component is likely to lead to reduced periprosthetic bone loss as compared to a cobalt-chromium component. A finite element model of a total knee arthroplasty subjected to a deep squat loading condition, which was previously published, was adapted with an alternative total knee arthroplasty design made of either polyetheretherketone or cobalt-chromium. The maximum tensile and compressive stresses within the implant and cement mantle were analysed against their yield and fatigue stress levels. The amount of stress shielding within the bone was compared between the polyetheretherketone and cobalt-chromium cases. Relative to its material strength, tensile peak stresses were higher in the cobalt-chromium implant; compressive peak stresses were higher in the polyetheretherketone implant. The stress patterns differed substantially between polyetheretherketone and cobalt-chromium. The tensile stresses in the cement mantle supporting the polyetheretherketone implant were up to 33% lower than with the cobalt-chromium component, but twice as high for compression. Stress shielding was reduced to a median of 1% for the polyetheretherketone implant versus 56% for the cobalt-chromium implant. Both the polyetheretherketone implant and the underlying cement mantle should be able to cope with the stress levels present during a deep squat. Relative to the cobalt-chromium component, stress shielding of the periprosthetic femur was substantially less with a polyetheretherketone femoral component.

Corrosion on the acetabular liner taper from retrieved modular metal-on-metal total hip replacements.

PubMed

Gascoyne, Trevor C; Dyrkacz, Richard M; Turgeon, Thomas R; Burnell, Colin D; Wyss, Urs P; Brandt, Jan-M

2014-10-01

Eight retrieved metal-on-metal total hip replacements displayed corrosion damage along the cobalt-chromium alloy liner taper junction with the Ti alloy acetabular shell. Scanning electron microscopy indicated the primary mechanism of corrosion to be grain boundary and associated crevice corrosion, which was likely accelerated through mechanical micromotion and galvanic corrosion resulting from dissimilar alloys. Coordinate measurements revealed up to 4.3mm(3) of the cobalt-chromium alloy taper surface was removed due to corrosion, which is comparable to previous reports of corrosion damage on head-neck tapers. The acetabular liner-shell taper appears to be an additional source of metal corrosion products in modular total hip replacements. Patients with these prostheses should be closely monitored for signs of adverse reaction towards corrosion by-products. Copyright © 2014 Elsevier Inc. All rights reserved.

An in vitro simulation model to assess the severity of edge loading and wear, due to variations in component positioning in hip joint replacements.

PubMed

O'Dwyer Lancaster-Jones, O; Williams, S; Jennings, L M; Thompson, J; Isaac, G H; Fisher, J; Al-Hajjar, M

2017-09-23

The aim of this study was to develop a preclinical in vitro method to predict the occurrence and severity of edge loading condition associated with the dynamic separation of the centres of the head and cup (in the absence of impingement) for variations in surgical positioning of the cup. Specifically, this study investigated the effect of both the variations in the medial-lateral translational mismatch between the centres of the femoral head and acetabular cup and the variations in the cup inclination angles on the occurrence and magnitude of the dynamic separation, the severity of edge loading, and the wear rate of ceramic-on-ceramic hip replacement bearings in a multi-station hip joint simulator during a walking gait cycle. An increased mismatch between the centres of rotation of the femoral head and acetabular cup resulted in an increased level of dynamic separation and an increase in the severity of edge loading condition which led to increased wear rate in ceramic-on-ceramic bearings. Additionally for a given translational mismatch, an increase in the cup inclination angle gave rise to increased dynamic separation, worst edge loading conditions, and increased wear. To reduce the occurrence and severity of edge loading, the relative positions (the mismatch) of the centres of rotation of the head and the cup should be considered alongside the rotational position of the acetabular cup. This study has considered the combination of mechanical and tribological factors for the first time in the medial-lateral axis only, involving one rotational angle (inclination) and one translational mismatch. © 2017 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc.

Investigation on the potential of waste cooking oil as a grinding aid in Portland cement.

PubMed

Li, Haoxin; Zhao, Jianfeng; Huang, Yuyan; Jiang, Zhengwu; Yang, Xiaojie; Yang, Zhenghong; Chen, Qing

2016-12-15

Although there are several methods for managing waste cooking oil (WCO), a significant result has not been achieved in China. A new method is required for safe WCO management that minimizes the environmental threat. In this context, this work was developed in which cement clinker and gypsum were interground with various WCOs, and their properties, such as grindability, water-cement ratio required to achieve a normal consistency, setting times, compressive strength, contents of calcium hydroxide and ettringite in the hardened paste, microstructure and economic and environmental considerations, were addressed in detail. The results show that, overall, WCO favorably improves cement grinding. WCO prolonged the cement setting times and resulted in longer setting times. Additionally, more remarkable effects were found in cements in which WCO contained more unsaturated fatty acid. WCOs increased the cement strength. However, this enhancement was rated with respect to the WCO contents and components. WCOs decreased the CH and AFt contents in the cement hardened paste. Even the AFt content at later ages was reduced when WCO was used. WCO also densify microstructure of the hardened cement paste. It is economically and environmentally feasible to use WCOs as grinding aids in the cement grinding process. These results contribute to the application of WCOs as grinding aids and to the safe management of WCO. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mechanobiological simulations of peri-acetabular bone ingrowth: a comparative analysis of cell-phenotype specific and phenomenological algorithms.

PubMed

Mukherjee, Kaushik; Gupta, Sanjay

2017-03-01

Several mechanobiology algorithms have been employed to simulate bone ingrowth around porous coated implants. However, there is a scarcity of quantitative comparison between the efficacies of commonly used mechanoregulatory algorithms. The objectives of this study are: (1) to predict peri-acetabular bone ingrowth using cell-phenotype specific algorithm and to compare these predictions with those obtained using phenomenological algorithm and (2) to investigate the influences of cellular parameters on bone ingrowth. The variation in host bone material property and interfacial micromotion of the implanted pelvis were mapped onto the microscale model of implant-bone interface. An overall variation of 17-88 % in peri-acetabular bone ingrowth was observed. Despite differences in predicted tissue differentiation patterns during the initial period, both the algorithms predicted similar spatial distribution of neo-tissue layer, after attainment of equilibrium. Results indicated that phenomenological algorithm, being computationally faster than the cell-phenotype specific algorithm, might be used to predict peri-prosthetic bone ingrowth. The cell-phenotype specific algorithm, however, was found to be useful in numerically investigating the influence of alterations in cellular activities on bone ingrowth, owing to biologically related factors. Amongst the host of cellular activities, matrix production rate of bone tissue was found to have predominant influence on peri-acetabular bone ingrowth.

The developing juvenile ischium: macro-radiographic insights.

PubMed

Maclean, Stephen J; Black, Sue M; Cunningham, Craig A

2014-09-01

Despite the importance of the human pelvis as a weight-bearing structure, there is a paucity of literature that discusses the development of the juvenile innominate from a biomechanical perspective. This study aims to add to the limited body of literature pertaining to this topic through the qualitative analysis of the gross architecture of the human ischium during the juvenile period. Macro-radiographs of 55 human ischia ranging from 28 intra-uterine weeks to 14 years of age were examined using intensity-gradient color mapping to highlight changes in gross structural morphology with increasing age. A clear pattern of maturation was observed in the juvenile ischium with increasing age. The acetabular component and ramus of the ischium consistently displayed low bone intensity in the postnatal skeletal material. Conversely the posterior body of the ischium, and in particular the ischial spine and lesser sciatic notch, exhibited increasing bone intensity which first arose at 1-2 years of age and became more expansive in older cohorts. The intensity patterns observed within the developing juvenile ischium are indicative of the potential factors influencing the maturation of this skeletal element. While the low intensity acetabular fossa indicates a lack of significant biomechanical interactions, the posterior increase in bone intensity may be related to the load-bearing nature of the posterior ischium. © 2014 Wiley Periodicals, Inc.

Design of Bioactive Organic-inorganic Hybrid Materials with Self-setting Ability

NASA Astrophysics Data System (ADS)

Miyazaki, T.; Machida, S.; Morita, Y.; Ishida, E.

2011-10-01

Paste-like materials with ability of self-setting are attractive for bone substitutes, since they can be injected from the small hole with minimized invasion to the patient. Although bone cements which set as apatite are clinically used, there is limitation on clinical applications due to their mechanical properties such as high brittleness and low fracture toughness. To overcome this problem, organic-inorganic hybrids based on a flexible polymer are attractive. We have obtained an idea for design of self-setting hybrids using polyion complex fabricated by ionic interaction of anionic and cationic polymers. We aimed at preparation of organic-inorganic hybrids exhibiting self-setting ability and bioactivity. The liquid component was prepared from cationic chitosan aqueous solution. The powder component was prepared by mixing various carrageenans with α-tricalcium phosphate (α-TCP). The obtained cements set within 1 day. Compressive strength showed tendency to increase with increase in α-TCP content in the powder component. The prepared cements formed the apatite in simulated body fluid within 3 days. Novel self-setting materials based on organic-inorganic hybrid can be designed utilizing ionic interaction of polysaccharide.

Development of road soil cement compositions modified with complex additive based on polycarboxylic ether

NASA Astrophysics Data System (ADS)

Bulanov, P. E.; Vdovin, E. A.; Mavliev, L. F.; Kuznetsov, D. A.

2018-03-01

The paper is focused on the research results of the main physical and technical properties of the cement-stabilized polymineral clay modified with a complex hydrophobic plasticizer based on polycarboxylate and octyltriethoxysilane ethers. A graphical result interpretation of the mathematic model which shows the influence of the complex hydrophobic plasticizer components on the cement-stabilized polymineral clay, containing more than 85% of relict minerals, has been designed. The research significance for the building sector lies in the fact that applying a complex hydrophobic plasticizer provides increasing the compressive strength of the cement-stabilized polymineral clay up to 102%, the tensile bending strength – up to 88%, the freeze-thaw resistance – up to 114%.

Polymer-Cement Composites Containing Waste Perlite Powder

PubMed Central

Łukowski, Paweł

2016-01-01

Polymer-cement composites (PCCs) are materials in which the polymer and mineral binder create an interpenetrating network and co-operate, significantly improving the performance of the material. On the other hand, the need for the utilization of waste materials is a demand of sustainable construction. Various mineral powders, such as fly ash or blast-furnace slag, are successfully used for the production of cement and concrete. This paper deals with the use of perlite powder, which is a burdensome waste from the process of thermal expansion of the raw perlite, as a component of PCCs. The results of the testing of the mechanical properties of the composite and some microscopic observations are presented, indicating that there is a possibility to rationally and efficiently utilize waste perlite powder as a component of the PCC. This would lead to creating a new type of building material that successfully meets the requirements of sustainable construction. PMID:28773961

Experimental Study of Cement - Sandstone/Shale - Brine - CO2 Interactions

PubMed Central

2011-01-01

Background Reactive-transport simulation is a tool that is being used to estimate long-term trapping of CO2, and wellbore and cap rock integrity for geologic CO2 storage. We reacted end member components of a heterolithic sandstone and shale unit that forms the upper section of the In Salah Gas Project carbon storage reservoir in Krechba, Algeria with supercritical CO2, brine, and with/without cement at reservoir conditions to develop experimentally constrained geochemical models for use in reactive transport simulations. Results We observe marked changes in solution composition when CO2 reacted with cement, sandstone, and shale components at reservoir conditions. The geochemical model for the reaction of sandstone and shale with CO2 and brine is a simple one in which albite, chlorite, illite and carbonate minerals partially dissolve and boehmite, smectite, and amorphous silica precipitate. The geochemical model for the wellbore environment is also fairly simple, in which alkaline cements and rock react with CO2-rich brines to form an Fe containing calcite, amorphous silica, smectite and boehmite or amorphous Al(OH)3. Conclusions Our research shows that relatively simple geochemical models can describe the dominant reactions that are likely to occur when CO2 is stored in deep saline aquifers sealed with overlying shale cap rocks, as well as the dominant reactions for cement carbonation at the wellbore interface. PMID:22078161

Utilization of municipal sewage sludge as additives for the production of eco-cement.

PubMed

Lin, Yiming; Zhou, Shaoqi; Li, Fuzhen; Lin, Yixiao

2012-04-30

The effects of using dried sewage sludge as additive on cement property in the process of clinker burning were investigated in this paper. The eco-cement samples were prepared by adding 0.50-15.0% of dried sewage sludge to unit raw meal, and then the mixtures were burned at 1450 °C for 2 h. The results indicated that the major components in the eco-cement clinkers were similar to those in ordinary Portland cement. Although the C(2)S phase formation increased with the increase of sewage sludge content, it was also found that the microstructure of the mixture containing 15.0% sewage sludge in raw meal was significantly different and that a larger amount of pores were distributed in the clinker. Moreover, all the eco-cement pastes had a longer initial setting time and final setting time than those of plain cement paste, which increased as the sewage sludge content in the raw meal increased. All the eco-cement pastes had lower early flexural strengths, which increased as the sewage sludge content increased, while the compressive strengths decreased slightly. However, this had no significant effect on all the strengths at later stages. Furthermore, the leaching concentrations of all the types of eco-cement clinkers met the standard of Chinese current regulatory thresholds. Copyright © 2012 Elsevier B.V. All rights reserved.

Molecular architecture requirements for polymer-grafted lignin superplasticizers.

PubMed

Gupta, Chetali; Sverdlove, Madeline J; Washburn, Newell R

2015-04-07

Superplasticizers are a class of anionic polymer dispersants used to inhibit aggregation in hydraulic cement, lowering the yield stress of cement pastes to improve workability and reduce water requirements. The plant-derived biopolymer lignin is commonly used as a low-cost/low-performance plasticizer, but attempts to improve its effects on cement rheology through copolymerization with synthetic monomers have not led to significant improvements. Here we demonstrate that kraft lignin can form the basis for high-performance superplasticizers in hydraulic cement, but the molecular architecture must be based on a lignin core with a synthetic-polymer corona that can be produced via controlled radical polymerization. Using slump tests of ordinary Portland cement pastes, we show that polyacrylamide-grafted lignin prepared via reversible addition-fragmentation chain transfer polymerization can reduce the yield stress of cement paste to similar levels as a leading commercial polycarboxylate ether superplasticizer at concentrations ten-fold lower, although the lignin material produced via controlled radical polymerization does not appear to reduce the dynamic viscosity of cement paste as effectively as the polycarboxylate superplasticizer, despite having a similar affinity for the individual mineral components of ordinary Portland cement. In contrast, polyacrylamide copolymerized with a methacrylated kraft lignin via conventional free radical polymerization having a similar overall composition did not reduce the yield stress or the viscosity of cement pastes. While further work is required to elucidate the mechanism of this effect, these results indicate that controlling the architecture of polymer-grafted lignin can significantly enhance its performance as a superplasticizer for cement.

The effects of modern cementing techniques on the longevity of total hip arthroplasty.

PubMed

Poss, R; Brick, G W; Wright, R J; Roberts, D W; Sledge, C B

1988-07-01

Modern prosthetic design and cementing techniques have dramatically improved femoral component fixation. Compared to studies reported in the 1970s, the incidence of radiographic loosening for periods up to 5 years postoperatively has been reduced by at least a factor of 10. These results are the benchmark by which alternative forms of femoral component fixation must be measured. With the likelihood of increased longevity of total hip arthroplasty resulting from improved fixation, the problems of wear debris from the bearing surfaces and loss of bone stock with time will become preeminent.

Effect of Strength Enhancement of Soil Treated with Environment-Friendly Calcium Carbonate Powder

PubMed Central

Park, Kyungho; Jun, Sangju; Kim, Daehyeon

2014-01-01

This study aims to investigate the effects of the strength improvement of soft ground (sand) by producing calcium carbonate powder through microbial reactions. To analyze the cementation effect of calcium carbonate produced through microbial reaction for different weight ratios, four different types of specimens (untreated, calcium carbonate, cement, and calcium carbonate + cement) with different weight ratios (2%, 4%, 6%, and 8%) were produced and cured for a period of 3 days, 7 days, 14 days, 21 days, and 28 days to test them. The uniaxial compression strength of specimens was measured, and the components in the specimen depending on the curing period were analyzed by means of XRD analysis. The result revealed that higher weight ratios and longer curing period contributed to increased strength of calcium carbonate, cement, and calcium carbonate + cement specimens. The calcium carbonate and the calcium carbonate + cement specimens in the same condition showed the tendency of decreased strength approximately 3 times and two times in comparison with the 8% cement specimens cured for 28 days, but the tendency of increased strength was approximately 4 times and 6 times in comparison with the untreated specimen. PMID:24688401

Effect of strength enhancement of soil treated with environment-friendly calcium carbonate powder.

PubMed

Park, Kyungho; Jun, Sangju; Kim, Daehyeon

2014-01-01

This study aims to investigate the effects of the strength improvement of soft ground (sand) by producing calcium carbonate powder through microbial reactions. To analyze the cementation effect of calcium carbonate produced through microbial reaction for different weight ratios, four different types of specimens (untreated, calcium carbonate, cement, and calcium carbonate + cement) with different weight ratios (2%, 4%, 6%, and 8%) were produced and cured for a period of 3 days, 7 days, 14 days, 21 days, and 28 days to test them. The uniaxial compression strength of specimens was measured, and the components in the specimen depending on the curing period were analyzed by means of XRD analysis. The result revealed that higher weight ratios and longer curing period contributed to increased strength of calcium carbonate, cement, and calcium carbonate + cement specimens. The calcium carbonate and the calcium carbonate + cement specimens in the same condition showed the tendency of decreased strength approximately 3 times and two times in comparison with the 8% cement specimens cured for 28 days, but the tendency of increased strength was approximately 4 times and 6 times in comparison with the untreated specimen.

Sample environment for in situ synchrotron XRD measurements for CO2 interaction with subsurface materials

NASA Astrophysics Data System (ADS)

Elbakhshwan, M.; Gill, S.; Weidner, R.; Ecker, L.

2017-12-01

Sequestration of CO2 in geological formations requires a deep understanding of its interaction with the cement-casing components in the depleted oil and gas wells. Portland cement is used to seal the wellbores; however it tends to interact with the CO2. Therefore it is critical to investigate the wellbore integrity over long term exposure to CO2. Studies showed that, CO2 leakage is due to the flow through the casing-cement microannulus, cement-cement fractures, or the cement-caprock interface. The objective of this work is to gain a better understanding of the dissolution process of the cement-casing in the CO2 flow channels alongside with the carbonation reactions at the interfaces using XRF, XANES and X-ray tomography techniques. In this study, a synthetic wellbore system, consisting of cement with an embedded rectangular length of steel casing that had grooves to accommodate fluid flow, was used to investigate the casing-cement microannulus through core-flood experiments. The objective of this work is to gain a better understanding of the dissolution process of the cement-casing in the CO2 flow channels alongside with the carbonation reactions at the interfaces using a sample environment designed and built for in situ X-ray diffraction in the National Synchrotron Light Source II (NSLS II). The formation of carbonate phases at cement -fluid and cement-steel/fluid interfaces will be monitored in real time. Samples may be exposed to super critical CO2 at pressures above 1100 psi and temperatures around 50°C. The reaction cell is built from hastealloy to provide corrosion resistance, while the experimental temperature and pressure are controlled with thermocouples and pressure vessel.

Effects of Titanium Mesh Surfaces-Coated with Hydroxyapatite/β-Tricalcium Phosphate Nanotubes on Acetabular Bone Defects in Rabbits

PubMed Central

Nguyen, Thuy-Duong Thi; Bae, Tae-Sung; Yang, Dae-hyeok; Park, Myung-sik; Yoon, Sun-jung

2017-01-01

The management of severe acetabular bone defects in revision reconstructive orthopedic surgery is challenging. In this study, cyclic precalcification (CP) treatment was used on both nanotube-surface Ti-mesh and a bone graft substitute for the acetabular defect model, and its effects were assessed in vitro and in vivo. Nanotube-Ti mesh coated with hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) was manufactured by an anodizing and a sintering method, respectively. An 8 mm diameter defect was created on each acetabulum of eight rabbits, then treated by grafting materials and covered by Ti meshes. At four and eight weeks, postoperatively, biopsies were performed for histomorphometric analyses. The newly-formed bone layers under cyclic precalcified anodized Ti (CP-AT) meshes were superior with regard to the mineralized area at both four and eight weeks, as compared with that under untreated Ti meshes. Active bone regeneration at 2–4 weeks was stronger than at 6–8 weeks, particularly with treated biphasic ceramic (p < 0.05). CP improved the bioactivity of Ti meshes and biphasic grafting materials. Moreover, the precalcified nanotubular Ti meshes could enhance early contact bone formation on the mesh and, therefore, may reduce the collapse of Ti meshes into the defect, increasing the sufficiency of acetabular reconstruction. Finally, cyclic precalcification did not affect bone regeneration by biphasic grafting materials in vivo. PMID:28686210

Atypical anterior wall fracture of the acetabulum: case series of anterior acetabular rim fracture without involvement of the pelvic brim.

PubMed

Lenarz, Christopher J; Moed, Berton R

2007-09-01

The purpose of this study was to describe a form of anterior wall acetabular fracture, which has been inadequately defined in the literature. Retrospective analysis of consecutive patients. Level 1 trauma center. A retrospective analysis of consecutive acetabulum patients treated by a single surgeon between 1999 and 2005 identified 6 patients with a form of anterior wall fracture without involvement of the pelvic brim. All fractures were treated operatively. Open reduction and internal fixation through an anterior surgical approach. Final radiographic appearance and modified Merle d'Aubigne score. All 6 cases demonstrated characteristics of an atypical fracture of the anterior wall, involving the anterior rim of the acetabulum similar in nature to those described for the posterior wall, rather than the standard anterior wall fracture type described by Letournel. Of the 6 cases that were identified, 5 had follow-up 1 year or greater with a mean modified Merle d'Aubigne Score of 17 (range: 17-18). A form of anterior wall acetabular fracture exists, which involves the anterior acetabular rim without involvement of the pelvic brim. It can occur in young patients with high-energy mechanisms of injury, as well as in the elderly with low-energy trauma. With appropriate surgical management, using a modified Smith-Peterson approach, good to excellent clinical outcomes should be expected.

Inter- and intra-observer variability of radiography and computed tomography for evaluation of Zurich cementless acetabular cup placement ex vivo.

PubMed

Leasure, Jessica O; Peck, Jeffrey N; Villamil, Armando; Fiore, Kara L; Tano, Cheryl A

2016-11-23

To evaluate the inter- and intra-observer variability in measurement of the angle of lateral opening (ALO) and version angle measurement using digital radiography and computed tomography (CT). Each hemipelvis was implanted with a cementless acetabular cup. Ventrodorsal and mediolateral radiographs were made of each pelvis, followed by CT imaging. After removal of the first cup, the pelves were implanted with an acetabular cup in the contralateral acetabulum and imaging was repeated. Three surgeons measured the ALO and version angles three times for each cup from the mediolateral radiographic projection. The same measurements were made using three-dimensional multiplanar reconstructions from CT images. Two anatomical axes were used to measure pelvic inclination in the sagittal plane, resulting in six measurements per cup. Two-way repeated measures analysis of variance evaluated inter- and intra-observer repeatability for radiographic and CT-based measurements. Version angle based on radiographic measurement did not differ within surgeons (p = 0.433), but differed between surgeons (p <0.001). Radiographic measurement of ALO differed within surgeons (p = 0.006) but not between surgeons (p = 0.989). The ALO and version angle measured on CT images did not differ with or between surgeons. Assessment of inter- and intra-observer measurement of ALO and version angle was more reproducible using CT images than conventional mediolateral radiography for a Zurich cementless acetabular cup.

A Prolonged Time Interval Between Trauma and Prophylactic Radiation Therapy Significantly Increases the Risk of Heterotopic Ossification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mourad, Waleed F., E-mail: Waleed246@gmail.com; Department of Radiation Oncology, Beth Israel Medical Center, New York, NY; Packianathan, Satyaseelan

2012-03-01

Purpose: To ascertain whether the time from injury to prophylactic radiation therapy (RT) influences the rate of heterotopic ossification (HO) after operative treatment of displaced acetabular fractures. Methods and Materials: This is a single-institution, retrospective analysis of patients referred for RT for the prevention of HO. Between January 2000 and January 2009, 585 patients with displaced acetabular fractures were treated surgically followed by RT for HO prevention. We analyzed the effect of time from injury on prevention of HO by RT. In all patients, 700 cGy was prescribed in a single fraction and delivered within 72 hours postsurgery. The patientsmore » were stratified into five groups according to time interval (in days) from the date of their accident to the date of RT: Groups A {<=}3, B {<=}7, C {<=}14, D {<=}21, and E >21days. Results: Of the 585 patients with displaced acetabular fractures treated with RT, (18%) 106 patients developed HO within the irradiated field. The risk of HO after RT increased from 10% for RT delivered {<=}3 days to 92% for treatment delivered >21 days after the initial injury. Wilcoxon test showed a significant correlation between the risk of HO and the length of time from injury to RT (p < 0.0001). Chi-square test and multiple logistic regression analysis showed no significant association between all other factors and the risk of HO (race, gender, cause and type of fracture, surgical approach, or the use of indomethacin). Conclusions: Our data suggest that there is higher incidence and risk of HO if prophylactic RT is significantly delayed after a displaced acetabular fracture. Thus, RT should be administered as early as clinically possible after the trauma. Patients undergoing RT >3 weeks from their displaced acetabular fracture should be informed of the higher risk (>90%) of developing HO despite prophylaxis.« less

Does semi-automatic bone-fragment segmentation improve the reproducibility of the Letournel acetabular fracture classification?

PubMed

Boudissa, M; Orfeuvre, B; Chabanas, M; Tonetti, J

2017-09-01

The Letournel classification of acetabular fracture shows poor reproducibility in inexperienced observers, despite the introduction of 3D imaging. We therefore developed a method of semi-automatic segmentation based on CT data. The present prospective study aimed to assess: (1) whether semi-automatic bone-fragment segmentation increased the rate of correct classification; (2) if so, in which fracture types; and (3) feasibility using the open-source itksnap 3.0 software package without incurring extra cost for users. Semi-automatic segmentation of acetabular fractures significantly increases the rate of correct classification by orthopedic surgery residents. Twelve orthopedic surgery residents classified 23 acetabular fractures. Six used conventional 3D reconstructions provided by the center's radiology department (conventional group) and 6 others used reconstructions obtained by semi-automatic segmentation using the open-source itksnap 3.0 software package (segmentation group). Bone fragments were identified by specific colors. Correct classification rates were compared between groups on Chi 2 test. Assessment was repeated 2 weeks later, to determine intra-observer reproducibility. Correct classification rates were significantly higher in the "segmentation" group: 114/138 (83%) versus 71/138 (52%); P<0.0001. The difference was greater for simple (36/36 (100%) versus 17/36 (47%); P<0.0001) than complex fractures (79/102 (77%) versus 54/102 (53%); P=0.0004). Mean segmentation time per fracture was 27±3min [range, 21-35min]. The segmentation group showed excellent intra-observer correlation coefficients, overall (ICC=0.88), and for simple (ICC=0.92) and complex fractures (ICC=0.84). Semi-automatic segmentation, identifying the various bone fragments, was effective in increasing the rate of correct acetabular fracture classification on the Letournel system by orthopedic surgery residents. It may be considered for routine use in education and training. III: prospective case-control study of a diagnostic procedure. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Evaluation of patients with painful total hip arthroplasty using combined single photon emission tomography and conventional computerized tomography (SPECT/CT) - a comparison of semi-quantitative versus 3D volumetric quantitative measurements.

PubMed

Barthassat, Emilienne; Afifi, Faik; Konala, Praveen; Rasch, Helmut; Hirschmann, Michael T

2017-05-08

It was the primary purpose of our study to evaluate the inter- and intra-observer reliability of a standardized SPECT/CT algorithm for evaluating patients with painful primary total hip arthroplasty (THA). The secondary purpose was a comparison of semi-quantitative and 3D volumetric quantification method for assessment of bone tracer uptake (BTU) in those patients. A novel SPECT/CT localization scheme consisting of 14 femoral and 4 acetabular regions on standardized axial and coronal slices was introduced and evaluated in terms of inter- and intra-observer reliability in 37 consecutive patients with hip pain after THA. BTU for each anatomical region was assessed semi-quantitatively using a color-coded Likert type scale (0-10) and volumetrically quantified using a validated software. Two observers interpreted the SPECT/CT findings in all patients two times with six weeks interval between interpretations in random order. Semi-quantitative and quantitative measurements were compared in terms of reliability. In addition, the values were correlated using Pearson`s correlation. A factorial cluster analysis of BTU was performed to identify clinically relevant regions, which should be grouped and analysed together. The localization scheme showed high inter- and intra-observer reliabilities for all femoral and acetabular regions independent of the measurement method used (semiquantitative versus 3D volumetric quantitative measurements). A high to moderate correlation between both measurement methods was shown for the distal femur, the proximal femur and the acetabular cup. The factorial cluster analysis showed that the anatomical regions might be summarized into three distinct anatomical regions. These were the proximal femur, the distal femur and the acetabular cup region. The SPECT/CT algorithm for assessment of patients with pain after THA is highly reliable independent from the measurement method used. Three clinically relevant anatomical regions (proximal femoral, distal femoral, acetabular) were identified.

Pelvic Incidence and Acetabular Version in Slipped Capital Femoral Epiphysis.

PubMed

Gebhart, Jeremy J; Bohl, Michael S; Weinberg, Douglas S; Cooperman, Daniel R; Liu, Raymond W

2015-09-01

The etiology of slipped capital femoral epiphysis (SCFE) is multifactorial, but the role of sagittal balance of the pelvis as a contributing factor to its development has not been well studied. Our primary purpose was to determine whether a smaller pelvic incidence (PI), a position-independent anatomic parameter that regulates pelvic orientation, could be a factor that increases shear stress in the epiphyseal growth plate and potentially contributes to the development of SCFE. We also set out to determine whether acetabular retroversion was associated with SCFE. We obtained 14 cadaveric pelvi from the Hamann-Todd Osteological Collection whose femurs showed evidence of post-SCFE deformity. Two hundred age-matched, sex-matched, and race-matched pelvi were used as controls. PI and acetabular version were measured using standardized lateral photographs and goniometers, respectively. T tests were performed to evaluate for differences in measured parameters between groups. The mean PI was 40.6±6.1 degrees for SCFE specimens and 47.4±9.9 degrees for normal specimens (P=0.01). The mean version of SCFE and normal acetabula was 15±7 and 17±6 degrees, respectively (P=0.39). There was also no significant difference in version between SCFE acetabula and the contralateral, uninvolved acetabular of the same specimen (15±7 vs. 17±8 degrees, P=0.33). Specimens with SCFE deformity demonstrated a smaller PI than a large cohort of normal control specimens. We found no significant difference between acetabular version of specimens with and without SCFE deformity. Contralateral or unaffected acetabuli of SCFE specimens were not more retroverted than the affected side of the same specimen. Sagittal balance of the pelvis, and particularly decreased PI, may play an important role in the development of SCFE. The influence of mechanical factors beyond the hip joint in the development of SCFE should be considered by clinicians.

Two-Stage Revision for Infected Total Knee Arthroplasty: Based on Autoclaving the Recycled Femoral Component and Intraoperative Molding Using Antibiotic-Impregnated Cement on the Tibial Side.

PubMed

Lee, Byoung-Joo; Kyung, Hee-Soo; Yoon, Seong-Dae

2015-09-01

The purpose of this study was to determine the degree of infection control and postoperative function for new articulating metal-on-cement spacer. A retrospective study of 19 patients (20 cases), who underwent a two-stage revision arthroplasty using mobile cement prosthesis, were followed for a minimum of 2 years. This series consisted of 16 women and 3 men, having an overall mean age of 71 years. During the first stage of revision, the femoral implant and all the adherent cement was removed, after which it was autoclaved before replacement. The tibial component was removed and a doughy state, antibiotic-impregnated cement was inserted on the tibial side. To achieve joint congruency, intraoperative molding was performed by flexing and extending the knee joint. Each patient was evaluated clinically and radiologically. The clinical assessments included range of motion, and the patients were scored as per the Hospital for Special Surgery (HSS) and Knee Society (KS) criteria. The mean range of knee joint motion was 70° prior to the first stage operation and 72° prior to the second stage revision arthroplasty; following revision arthroplasty, it was 113° at the final follow-up. The mean HSS score and KS knee and function scores were 86, 82, and 54, respectively, at the final follow-up. The success rate in terms of infection eradication was 95% (19/20 knees). No patient experienced soft tissue contracture requiring a quadriceps snip. This novel technique provides excellent radiological and clinical outcomes. It offers a high surface area of antibiotic-impregnated cement, a good range of motion between first and second stage revision surgery for the treatment of chronic infection after total knee arthroplasty, and is of a reasonable cost.

The effectiveness of the stabilization/solidification process on the leachability and toxicity of the tannery sludge chromium.

PubMed

Montañés, M T; Sánchez-Tovar, R; Roux, M S

2014-10-01

A stabilization/solidification (S/S) process by using cement was applied to tannery sludge in order to find a safer way of landfilling this waste. The effects of three parameters on the process effectiveness were analysed in terms of leachate toxicity and chromium retention (%). The parameters studied were the relative amount of added water (30-50 wt.%), cement (10-60 wt.% in the solid components), and the use of three different types of cement (clinker with additions of limestone, with additions of limestone and fly ashes, and with additions of pozzolans). Statistical analysis performed by variance analysis and categorical multifactorial tests reveals that all the studied parameters significantly influence the effectiveness of the process. Results showed that chromium retention decreases as the relative amount of cement and water increases, probably due to additional chromium provided by cement and increased in the porosity of the mixtures. Leachate toxicity showed the same minimum value for mixtures with 30% or 40% cement, depending on the type of cement, showing that clinker is the main material responsible for the process effectiveness, and additives (pozzolans or fly ashes) do not improve it. The volume increase is lower as less sludge is replaced by cement and the relative amount of water decreases, and for the cement without additions of fly ashes or pozzolans. Therefore, the latter seems to be the most appropriate cement in spite of being more expensive. This is due to the fact that the minimum toxicity value is achieved with a lower amount of cement; and moreover, the volume increase in the mixtures is lower, minimizing the disposal cost to a landfill. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fabrication and wear test of a continuous fiber/particulate composite total surface hip replacement

NASA Technical Reports Server (NTRS)

Roberts, J. C.; Ling, F. F.; Jones, W. R., Jr.

1981-01-01

Continuous fiber woven E-glass composite femoral shells having the ame elastic properties as bone were fabricated. The shells were then encrusted with filled epoxy wear resistant coatings and run dry against ultrahigh molecular weight polyethylene acetabular cups in 42,000 and 250,000 cycle were tests on a total hip simulator. The tribological characteristics of these shells atriculating with the acetabular cups are comparable to a vitallium bal articulating with an ultrahigh molecular weight polyethylene cup.

Effects of a discoloration-resistant calcium aluminosilicate cement on the viability and proliferation of undifferentiated human dental pulp stem cells.

PubMed

Niu, Li-na; Watson, Devon; Thames, Kyle; Primus, Carolyn M; Bergeron, Brian E; Jiao, Kai; Bortoluzzi, Eduardo A; Cutler, Christopher W; Chen, Ji-hua; Pashley, David H; Tay, Franklin R

2015-11-30

Discoloration-resistant calcium aluminosilicate cement has been formulated to overcome the timely problem of tooth discoloration reported in the clinical application of bismuth oxide-containing hydraulic cements. The present study examined the effects of this experimental cement (Quick-Set2) on the viability and proliferation of human dental pulp stem cells (hDPSCs) by comparing the cellular responses with commercially available calcium silicate cement (white mineral trioxide aggregate; WMTA) after different aging periods. Cell viability and proliferation were examined using assays that examined plasma membrane integrity, leakage of cytosolic enzyme, caspase-3 activity for early apoptosis, oxidative stress, mitochondrial metabolic activity and intracellular DNA content. Results of the six assays indicated that both Quick-Set2 and WMTA were initially cytotoxic to hDPSCs after setting for 24 h, with Quick-Set2 being comparatively less cytotoxic than WMTA at this stage. After two aging cycles, the cytotoxicity profiles of the two hydraulic cements were not significantly different and were much less cytotoxic than the positive control (zinc oxide-eugenol cement). Based on these results, it is envisaged that any potential beneficial effect of the discoloration-resistant calcium aluminosilicate cement on osteogenesis by differentiated hDPSCs is more likely to be revealed after outward diffusion and removal of its cytotoxic components.

Effects of a discoloration-resistant calcium aluminosilicate cement on the viability and proliferation of undifferentiated human dental pulp stem cells

PubMed Central

Niu, Li-na; Watson, Devon; Thames, Kyle; Primus, Carolyn M.; Bergeron, Brian E.; Jiao, Kai; Bortoluzzi, Eduardo A.; Cutler, Christopher W.; Chen, Ji-hua; Pashley, David H.; Tay, Franklin R.

2015-01-01

Discoloration-resistant calcium aluminosilicate cement has been formulated to overcome the timely problem of tooth discoloration reported in the clinical application of bismuth oxide-containing hydraulic cements. The present study examined the effects of this experimental cement (Quick-Set2) on the viability and proliferation of human dental pulp stem cells (hDPSCs) by comparing the cellular responses with commercially available calcium silicate cement (white mineral trioxide aggregate; WMTA) after different aging periods. Cell viability and proliferation were examined using assays that examined plasma membrane integrity, leakage of cytosolic enzyme, caspase-3 activity for early apoptosis, oxidative stress, mitochondrial metabolic activity and intracellular DNA content. Results of the six assays indicated that both Quick-Set2 and WMTA were initially cytotoxic to hDPSCs after setting for 24 h, with Quick-Set2 being comparatively less cytotoxic than WMTA at this stage. After two aging cycles, the cytotoxicity profiles of the two hydraulic cements were not significantly different and were much less cytotoxic than the positive control (zinc oxide–eugenol cement). Based on these results, it is envisaged that any potential beneficial effect of the discoloration-resistant calcium aluminosilicate cement on osteogenesis by differentiated hDPSCs is more likely to be revealed after outward diffusion and removal of its cytotoxic components. PMID:26617338

Identifying improvement potentials in cement production with life cycle assessment.

PubMed

Boesch, Michael Elias; Hellweg, Stefanie

2010-12-01

Cement production is an environmentally relevant process responsible for 5% of total anthropogenic carbon dioxide emissions and 7% of industrial fuel use. In this study, life cycle assessment is used to evaluate improvement potentials in the cement production process in Europe and the USA. With a current fuel substitution rate of 18% in Europe and 11% in the USA, both regions have a substantial potential to reduce greenhouse gas emissions and save virgin resources by further increasing the coprocessing of waste fuels. Upgrading production technology would be particularly effective in the USA where many kiln systems with very low energy efficiency are still in operation. Using best available technology and a thermal substitution rate of 50% for fuels, greenhouse gas emissions could be reduced by 9% for Europe and 18% for the USA per tonne of cement. Since clinker production is the dominant pollution producing step in cement production, the substitution of clinker with mineral components such as ground granulated blast furnace slag or fly ash is an efficient measure to reduce the environmental impact. Blended cements exhibit substantially lower environmental footprints than Portland cement, even if the substitutes feature lower grindability and require additional drying and large transport distances. The highest savings in CO(2) emissions and resource consumption are achieved with a combination of measures in clinker production and cement blending.

Controversies in Treatment of Acetabular Fracture

PubMed Central

Grubor, Predrag; Krupic, Ferid; Biscevic, Mirza; Grubor, Milan

2015-01-01

Introduction: Acetabular fractures treatment represents a great controversy, challenge and dilemma for an orthopedic surgeon. Aim: The aim of the paper was to present the results of treatment of 96 acetabular fractures in the Clinic of Traumatology Banja Luka, in the period from 2003 to 2013, as well as to raise awareness regarding the controversy in the methods of choice in treating acetabulum fractures. Material and methods: The series consists of 96 patients, 82 males and 14 females, average age 40.5 years. Traffic trauma was the cause of fractures in 79 patients (85%), and in 17 patients (15%) fractures occurred due to falls from height. Polytrauma was present in 31 patients (32%). According to the classification of Judet and Letournel, representation of acetabular fractures was as follows: posterior wall in 32 patients, posterior column in 28, anterior wall in 4, anterior column in 2, transverse fractures in 8, posterior wall and posterior column in 10, anterior and posterior wall in 6, both- column in 4 and transversal fracture and posterior wall in 2 patients. 14 patients were treated with traction, that is, 6 patients with femoral traction and 8 patients with both lateral and femoral traction. 82 patients (86.4%) were surgically treated. Kocher-Langenbeck approach was applied in the treatment of 78 patients. In two patients from the Kocher-Langenbeck’s approach, the Ollier’s approach had to be applied as well. Two acetabular were primarily treated with Ollier’s approach. Extended Smith- Peterson’s approach was applied 4 times, and Emile Letournel’s (ilioinguinal) approach 14 times. Results: Functional outcome (after follow-up of 18 months), according to the Harris hip score of surgical treatment in 82 patients, was as follows: good 46 (56%), satisfactory 32 (39%) and poor 4 (5%). Results of acetabulum fractures treated with traction were: good 8 (57%), satisfactory 4 (28%) and poor 2 (15%). According to the Brook’s classification of heterotopic ossification, periarticular hetero-tropic calcifications after surgical treatment were: 0° in 65 patients (79%), I-II° in 9 patients (11%) and III-IV ° in 8 patients (10%). Calcifications in 14 patients treated with traction of heterotopic ossification by Brook-s classification were as follows: 0° in 10 patients (72%), I-II ° in 3 patients (22%) and III-IV° in 1 patient (6%). Conclusion: At the occurrence of acetabular fracture, it is necessary to start the treatment immediately, with an obligatory application of thromboembolic and antibiotic prophylaxis. Conservative treatment is acceptable if the dislocation of fracture is less than 5 mm. Indications for surgical treatment are incongruent or unstable fractures with verified dislocation greater than 5 mm, as well as when the radiography measured by JM Matta shows incongruence of acetabular roof less than 40° in all planes. Kocher-Langenbeck approach is the choice of surgical approach for the management of posterior column / wall, and Letournel’s (ilioinguinal) approach is the choice for the management of anterior wall/column. PMID:25870470

[Mathematical simulation of stem/cement/bone mechanical interactions for Poldi-Cech, CF-30, MS-30 and PFC femoral components].

PubMed

Kovanda, M; Havlícek, V; Hudec, J

2009-04-01

PURPOSE OF THE STUDY The mid-term longevity of femoral components varies considerably, with some showing failure due to early aseptic loosening. Since the hip joint is subject to heavy mechanical loads, it can be assumed that the mechanical interaction of the implant, bone cement and femur will play a key role in the resultant reliability of an arthroplasty. This study was designed to examine this mechanical interaction in four femoral components different in construction (Poldi-Cech, CF-30, MS-30 and PFC) using mathematical simulation. MATERIAL AND METHODS Four stem/cement/femur 3-D mathematical models, comparable in quality, infolving the Poldi-Cech, CF-30, MS-30 and PFC stems, respectively, were constructed. A 3-D model for each stem was created according to its real, middle-size femoral component. Each 3-D model of the cement mantle corresponded in shape to the mantle of the appropriate real stem, with its thickness based on the recommended values of 4-7 mm in the proximal and 1-3 mm in the distal part, and with the cement mantle reaching as far as 10 mm distal to the femoral stem tip. For simplicitys sake the outer surface of the cement mantle was simulated as smooth. A 3-D model involving the proximal epiphysis and the metaphysis of a femur was reconstructed, based on a series of CT cross-sections obtained periodically at 10.5-mm and 2.5-mm distances. The sten/cement/femur model with the MS-30 stem also included a centraliser. The mechanical interaction of the stem, bone cement and bone tissue was examined by means of mathematical stimulation using ANSYS 5.7 software based on finite element analysis. RESULTS For the sake of simplicity, only two key parameters are presented, namely, contact stress at the stem-cement interface and equivalent deformation in the stem/cement/femur system. The least satisfactory stress loading was in the CF-30 stem whose sharp edges showed the values of contact stress about six-times higher than on the mid-medial portion of the stem, with the sharp edges behaving as stress concentrators. A satisfactory stress loading was found in Poldi-Cech, MS-30 and PFC stems, in which contact stress was evenly distributed along the whole lenght of the stem and the values at the edges and on the midmedial portion did not differ much. DISCUSSION The distribution of contact stress is one of the most important factors for the long-term longevity of implants. It was found least satisfactory in the CF-30 stem whose sharp edges act as stress condenser adversely affecting not only the stemcement interface, but also the resultant stress distribution within the femur. The most satisfactory results of stress distribution were recorded in the Poldi-Cech and MS-30 stems. The PFC stem also responded satisfactorily to the simulated stress loading. However, on loading whose substantial part would be torsion, the stems circular or oval cross-section could interfere with rotation stability of the implant; but this was impossible to detect by the mathematical simulation used in this study. CONCLUSIONS The results presented here show that, in the Poldi-Cech, CF-30, MS-30 and PFC femoral stems, a good agreement was achieved between the results of their clinical application and those of mathematical modelling of their mechanical properties. It can be concluded that mechanical interaction among the femoral stem, cement mantle and bone tissue plays the key role in the long-term longevity of such an implant. Key words: Poldi-Cech, CF-30, MS-30, PFC, mechanical interaction, contact stress.

High temperature polymer concrete

DOEpatents

Fontana, J.J.; Reams, W.

1984-05-29

This invention is concerned with a polymer concrete composition, which is a two-component composition useful with many bases including metal. Component A, the aggregate composition, is broadly composed of silica, silica flour, portland cement, and acrylamide, whereas Component B, which is primarily vinyl and acrylyl reactive monomers, is a liquid system.

In vitro Characteristics of a Glass Ionomer Cement.

PubMed

Driscoll, C L; Green, J D; Beatty, C W; McCaffrey, T V; Marrs, C D

1998-01-01

Glass ionomer cements were first described by Wilson and Kent and have been used in dentistry since 1969. It has been recommended for bridging ossicular chain defects, fixation of ossicular chain prosthesis, anchoring of cochlear implants, mastoid obliteration, and repair of tegmen and posterior canal wall defects. The biocompatability and stability of this material over time is vital to its usefulness in neurotologic surgery. The purpose of this study was to assess the stability of a glass ionomer cement in the presence of bacteria and in different pH environments. We demonstrated that bacteria readily adhere to the surface and their presence is associated with accelerated loss of matrix. We found the cement to be susceptible to low pH and to release a visible cloud of debris upon contact with fluid. Calcium concentration in the solution was elevated at all pH levels. Although we are able to demonstrate these findings in vitro the clinical relevance is unclear. There have been several cases of aseptic meningitis possibly due to intracranial release of components of the cement. Until further studies are done use of the cement in contact with cerebral spinal fluid should be avoided. This cement, or a similar material, would be useful in neurotologic surgery but prior to widespread use further testing should be done to assess safety.

Quality design of belite–melilite clinker

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurokawa, Daisuke, E-mail: daisuke_kurokawa@taiheiyo-cement.co.jp; Department of Materials Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555; Honma, Kenichi

2013-12-15

We have developed a new cement clinker, consisting mainly of belite and melilite, which is capable of increasing the amount of recycled waste as a part of its raw materials. We analyzed clinkers with a wide range of compositions, and clarified the quantitative relationship between the chemical and mineral compositions. Clinkers consisting mostly of belite and melilite were successfully obtained at the CaO/SiO{sub 2} mass ratio of 1.7 to 1.9. Test cements were prepared using these clinkers and mixed with OPC for the evaluation of fluidity and strength. The belite–melilite cement was found to have good fluidity, and the belite–melilitemore » cement mixed with OPC at up to 30% exhibited a satisfactory long term strength equivalent to the OPC, demonstrating the potential as an alternative to OPC. Electron probe microanalysis revealed the relatively high concentration of diphosphorus pentaoxide in belite, suggesting this component might contribute to the strength enhancement of the cement. -- Highlights: •A new cement clinker consisting mainly of belite and melilite was designed. •The clinker enables the use of various recycled wastes as part of its raw materials. •The relationship between the chemical and mineral compositions was clarified. •This cement mixed with OPC at up to 30% exhibited a good quality equivalent to OPC.« less

Early polyethylene wear and osteolysis with ABG acetabular cups (7- to 12-year follow-up).

PubMed

Badhe, Sachin; Livesley, Peter

2006-02-01

We reviewed 81 consecutive ABG I primary total hip replacements implanted in 72 patients between January 1993 and December 1998. The mean follow-up was 8.2 (range 7-12) years. There was significant polyethylene wear and osteolysis associated with the acetabular cup . The cumulative survival of the cup with revision being the end point at 8.2 years was 95.1% (95% CI: 92-97.6%). However, the cumulative survival of the cup with revision and aseptic loosening together was 72% (95% CI: 61-78%) and survival of the acetabular liner for wear was 62% (95% CI: 48-74%). Stem survival with revision being the end point was 100%. In spite of significant radiological failures of the cups, most patients remained asymptomatic. Though results of the ABG stems in this series were good, we advocate a regular follow-up of all these hips in view of the poor outcome of the cups.

Early polyethylene wear and osteolysis with ABG acetabular cups (7- to 12-year follow-up)

PubMed Central

Livesley, Peter

2005-01-01

We reviewed 81 consecutive ABG I primary total hip replacements implanted in 72 patients between January 1993 and December 1998. The mean follow-up was 8.2 (range 7–12) years. There was significant polyethylene wear and osteolysis associated with the acetabular cup .The cumulative survival of the cup with revision being the end point at 8.2 years was 95.1% (95% CI: 92–97.6%). However, the cumulative survival of the cup with revision and aseptic loosening together was 72% (95% CI: 61–78%) and survival of the acetabular liner for wear was 62% (95% CI: 48–74%). Stem survival with revision being the end point was 100%. In spite of significant radiological failures of the cups, most patients remained asymptomatic. Though results of the ABG stems in this series were good, we advocate a regular follow-up of all these hips in view of the poor outcome of the cups. PMID:16283307

Press-fit versus threaded acetabular cups in total hip arthroplasty: Functional and radiological results after five years.

PubMed

Ellenrieder, Martin; Bader, Rainer; Bergschmidt, Philipp; Mittelmeier, Wolfram

2016-03-01

Prospectively the outcome after total hip replacement with a new threaded acetabular cup design was compared to an established press-fit cup. After 1, 2 and 5 years, the 36-item Short Form Health Survey, Western Ontario and McMaster University Osteoarthritis Index and Harris Hip Score revealed no significant differences between the two groups (each group: n=42 patients), except for a higher Harris Hip Score in the threaded cup group after five years (p=0.02). After five years, one threaded cup had a mild radiolucent line without further signs of loosening. All other cups of both groups (98.6%) showed a full osseous integration. The cup inclination angle ranged from 41-58° (threaded cups) to 39-77° (press-fit cups). The new threaded cup provides equivalent clinical outcomes and osseous integration but more precise implant positioning compared to the press-fit design. No complications typically ascribed to threaded cups (acetabular fractures, bone resorption, nerve impairment) occurred.

Hip2Norm: an object-oriented cross-platform program for 3D analysis of hip joint morphology using 2D pelvic radiographs.

PubMed

Zheng, G; Tannast, M; Anderegg, C; Siebenrock, K A; Langlotz, F

2007-07-01

We developed an object-oriented cross-platform program to perform three-dimensional (3D) analysis of hip joint morphology using two-dimensional (2D) anteroposterior (AP) pelvic radiographs. Landmarks extracted from 2D AP pelvic radiographs and optionally an additional lateral pelvic X-ray were combined with a cone beam projection model to reconstruct 3D hip joints. Since individual pelvic orientation can vary considerably, a method for standardizing pelvic orientation was implemented to determine the absolute tilt/rotation. The evaluation of anatomically morphologic differences was achieved by reconstructing the projected acetabular rim and the measured hip parameters as if obtained in a standardized neutral orientation. The program had been successfully used to interactively objectify acetabular version in hips with femoro-acetabular impingement or developmental dysplasia. Hip(2)Norm is written in object-oriented programming language C++ using cross-platform software Qt (TrollTech, Oslo, Norway) for graphical user interface (GUI) and is transportable to any platform.

Open reduction and internal fixation of osteoporotic acetabular fractures through the ilio-inguinal approach: use of buttress plates to control medial displacement of the quadrilateral surface.

PubMed

Peter, Robin E

2015-01-01

The number of acetabular fractures in the geriatric population requiring open reduction and internal fixation is increasing. Fractures with medial or anterior displacement are the most frequent types, and via the ilio-inguinal approach buttress plates have proved helpful to maintain the quadrilateral surface or medial acetabular wall. Seven to ten hole 3.5 mm reconstruction plates may be used as buttress plates, placed underneath the usual pelvic brim plate. This retrospective study presents our results with this technique in 13 patients at a minimum follow-up of 12 months (average, 31 months). 85% of the patients had a good result. The early onset of post-traumatic osteoarthritis necessitated total hip arthroplasty in two patients (15%) at 12 and 18 months follow-up, respectively. This treatment option should be considered in the surgeon's armamentarium when fixing these challenging cases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Computed tomography vs. digital radiography assessment for detection of osteolysis in asymptomatic patients with uncemented cups: a proposal for a new classification system based on computer tomography.

PubMed

Sandgren, Buster; Crafoord, Joakim; Garellick, Göran; Carlsson, Lars; Weidenhielm, Lars; Olivecrona, Henrik

2013-10-01

Digital radiographic images in the anterior-posterior and lateral view have been gold standard for evaluation of peri-acetabular osteolysis for patients with an uncemented hip replacement. We compared digital radiographic images and computer tomography in detection of peri-acetabular osteolysis and devised a classification system based on computer tomography. Digital radiographs were compared with computer tomography on 206 hips, with a mean follow up 10 years after surgery. The patients had no clinical signs of osteolysis and none were planned for revision surgery. On digital radiographs, 192 cases had no osteolysis and only 14 cases had osteolysis. When using computer tomography there were 184 cases showing small or large osteolysis and only 22 patients had no osteolysis. A classification system for peri-acetabular osteolysis is proposed based on computer tomography that is easy to use on standard follow up evaluation. Copyright © 2013 Elsevier Inc. All rights reserved.

Inducible displacement of cemented tibial components ten years after total knee arthroplasty.

PubMed

Lam Tin Cheung, K; Lanting, B A; McCalden, R W; Yuan, X; MacDonald, S J; Naudie, D D; Teeter, M G

2018-02-01

The aim of this study was to evaluate the long-term inducible displacement of cemented tibial components ten years after total knee arthroplasty (TKA). A total of 15 patients from a previously reported prospective trial of fixation using radiostereometric analysis (RSA) were examined at a mean of 11 years (10 to 11) postoperatively. Longitudinal supine RSA examinations were acquired at one week, one year, and two years postoperatively and at final follow-up. Weight-bearing RSA examinations were also undertaken with the operated lower limb in neutral and in maximum internal rotation positions. Maximum total point motion (MTPM) was calculated for the longitudinal and inducible displacement examinations (supine versus standing, standing versus internal rotation, and supine versus standing with internal rotation). All patients showed some inducible displacement. Two patients with radiolucent lines had greater mean standing-supine MTPM displacement (1.35; sd 0.38) compared with the remaining patients (0.68; sd 0.36). These two patients also had a greater mean longitudinal MTPM at ten years (0.64; sd 0.50) compared with the remaining patients (0.39; sd 0.13 mm). Small inducible displacements in well-fixed cemented tibial components were seen ten years postoperatively, of a similar magnitude to that which has been reported for well-fixed components one to two years postoperatively. Greater displacements were found in components with radiolucent lines. Cite this article: Bone Joint J 2018;100-B:170-5. ©2018 The British Editorial Society of Bone & Joint Surgery.

Survivorship of the native hip joint after percutaneous repair of acetabular fractures in the elderly.

PubMed

Gary, Joshua L; Lefaivre, Kelly A; Gerold, Frank; Hay, Michael T; Reinert, Charles M; Starr, Adam J

2011-10-01

Our purpose was to examine survivorship of the native hip joint in patients ages 60 and over who underwent percutaneous reduction and fixation of acetabular fractures. A retrospective review at a University Level I Trauma Center was performed. Our institutional trauma database was reviewed. Patients aged 60 or older treated with percutaneous reduction and fixation of acetabular fractures between 1994 and 2007 were selected. 79 consecutive patients with 80 fractures were identified. Rate of conversion to total hip arthroplasty were used to construct a Kaplan-Meier curve showing survivorship of the native hip joint after treatment. 75 fractures had adequate clinical follow-up with a mean of 3.9 years (range 0.5-11.9 years). Average blood loss was 69 cc and there were no postoperative infections. 19/75 (25%) were converted to total hip arthroplasty at a mean time of 1.4 years after the index procedure. Survivorship analysis demonstrated a cumulative survival of 65% at 11.9 years of follow-up. There were no conversions to arthroplasty beyond 4.7 years postoperatively. There were no statistically significant associations between conversion to arthroplasty and age, sex, closed vs. limited open reduction, and simple vs. complex fracture pattern. Percutaneous fixation is a viable treatment option for patients age 60 or greater with acetabular fractures. Rates of conversion to total hip arthroplasty are comparable to open treatment methods and if conversion is required, soft tissues are preserved for future surgery. Copyright © 2010 Elsevier Ltd. All rights reserved.

[Osteosynthesis and cup revision in periprosthetic acetabulum fractures using a Kocher-Langenbeck approach].

PubMed

Schwabe, P; Märdian, S; Perka, C; Schaser, K-D

2016-04-01

Reconstruction/stable fixation of the acetabular columns to create an adequate periacetabular requirement for the implantation of a revision cup. Displaced/nondisplaced fractures with involvement of the posterior column. Resulting instability of the cup in an adequate bone stock situation. Periprosthetic acetabulum fractures with inadequate bone stock. Extended periacetabular defects with loss of anchorage options. Isolated periprosthetic fractures of the anterior column. Septic loosening. Dorsal approach. Dislocation of hip. Mechanical testing of inlaying acetabular cup. With unstable cup situation explantation of the cup, fracture fixation of acetabulum with dorsal double plate osteosynthesis along the posterior column. Cup revision. Hip joint reposition. Early mobilization; partial weight bearing for 12 weeks. Thrombosis prophylaxis. Clinical and radiological follow-ups. Periprosthetic acetabular fracture in 17 patients with 9 fractures after primary total hip replacement (THR), 8 after revision THR. Fractures: 12 due to trauma, 5 spontaneously; 7 anterior column fractures, 5 transverse fractures, 4 posterior column fractures, 1 two column fracture after hemiendoprosthesis. 5 type 1 fractures and 12 type 2 fractures. Operatively treated cases (10/17) received 3 reinforcement ring, 2 pedestal cup, 1 standard revision cup, cup-1 cage construct, 1 ventral plate osteosynthesis, 1 dorsal plate osteosynthesis, and 1 dorsal plate osteosynthesis plus cup revision (10-month Harris Hip Score 78 points). Radiological follow-up for 10 patients: consolidation of fractures without dislocation and a fixed acetabular cup. No revision surgeries during follow-up; 2 hip dislocations, 1 transient sciatic nerve palsy.

The effect of stem surface treatment and material on pistoning of ulnar components in linked cemented elbow prostheses.

PubMed

Hosein, Yara K; King, Graham J W; Dunning, Cynthia E

2013-09-01

The ulnar component of a total elbow replacement can fail by "pistoning." Stem surface treatments have improved stability at the stem-cement interface but with varied success. This study investigated the role of surface treatment and stem substrate material on implant stability under axial loading. Sixty circular stems (diameter, 8 mm) made of cobalt chrome (n = 30) or titanium (n = 30) had different surfaces: smooth, sintered beads, and plasma spray. The surface treatment length was either 10 mm or 20 mm. Stems were potted in bone cement, allowed to cure for 24 hours, and tested in a materials testing machine under a compressive staircase loading protocol. Failure was defined as 2 mm of push-out or completion of the protocol. Two-way analyses of variance compared the effects of surface treatment and substrate material on interface strength and motion. Significant interactions were found between surface treatment and substrate material for both interface strength and motion (P < .05). For titanium, the 20-mm beaded stems had greater interface strength than all other stems (P < .05) and had less motion than the 10-mm plasma-spray and smooth stems (P < .05). For cobalt chrome, the 20-mm beaded stems showed greater interface strength (P < .05) and similar motion (P > .05) to the 20-mm plasma-spray stems (P < .05), which outperformed all other stems (P < .05). Mechanisms of catastrophic failure varied: smooth stems debonded at the stem-cement interface, beaded stems experienced debonding of the beads from the stem, and plasma-spray stems showed loss of frictional force between the surface treatment and cement. Stem surface treatment can enhance ulnar component stability but is dependent on substrate material. Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Increased Mortality in Elderly Patients with Sarcopenia and Acetabular Fractures.

PubMed

Deren, Matthew E; Babu, Jacob; Cohen, Eric M; Machan, Jason; Born, Christopher T; Hayda, Roman

2017-02-01

Sarcopenia is a condition of clinically relevant loss of muscle mass and function. Acetabular fractures in elderly patients are common and difficult to treat. This study aimed to determine if sarcopenia is common in elderly patients with acetabular fractures and correlates with lower-energy mechanisms of injury, higher rates of complications, and higher mortality than patients with normal muscle mass. The Rhode Island Hospital Trauma Database was queried for patients who were ≥60 years of age from 2005 to 2014 using the International Classification of Diseases, Ninth Revision, code for closed acetabular fracture, 808.0. Charts were retrospectively reviewed for demographic data, operative intervention, mechanism of injury, mortality, comorbidities, and other factors. Computed tomography (CT) was used to determine the muscle cross-sectional area and to calculate the skeletal muscle index. The database revealed 192 patients coded for acetabular fracture; of these, 181 were correctly diagnosed. Ninety-nine patients had recorded body mass index (BMI) and adequate CT scans to measure the skeletal muscle index. Forty-two patients (42.4%) had sarcopenia, and 57 patients (57.6%) did not have sarcopenia. There were no significant differences in demographic characteristics between the groups with the exception of BMI and sex. BMI was higher in patients who did not have sarcopenia (31.7 kg/m) than it was in patients with sarcopenia (23.6 kg/m) (p < 0.001). Male sex was significantly greater (p = 0.0104) in patients with sarcopenia at 76.2% (32 of 42 patients) than in patients without sarcopenia at 50.9% (29 of 57 patients). Fractures in patients without sarcopenia were associated with a higher-energy mechanism of injury in 78.9% of cases compared with 52.4% of cases of patients with sarcopenia (p = 0.005). Sarcopenia was significantly associated (p = 0.0419) with increased 1-year mortality (28.6%) compared with the absence of sarcopenia (12.3%). This association was even stronger if in-hospital mortality was excluded (p = 0.00074). Finally, anterior column fractures were more likely (p = 0.017) to be sustained by patients with sarcopenia at 47.6% (20 patients) than by patients who did not have sarcopenia at 24.6% (14 patients). Sarcopenia is common in elderly patients with acetabular fractures and is associated with lower-energy mechanisms, anterior column fractures, and higher risk of 1-year mortality. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Periprosthetic Occult Fractures of the Acetabulum Occur Frequently During Primary THA.

PubMed

Hasegawa, Kazuhiro; Kabata, Tamon; Kajino, Yoshitomo; Inoue, Daisuke; Tsuchiya, Hiroyuki

2017-02-01

Periprosthetic fractures of the acetabulum occurring during primary THA are rare. Periprosthetic occult fractures are defined as those not identified by the surgeon during the procedure which might be missed on a routine postoperative radiograph. However, it is unclear how frequently these fractures occur and whether their presence affects functional recovery. In this study, using routine CT scans that were obtained as part of another primary hip arthroplasty study protocol, we retrospectively assessed (1) the prevalence of occult fractures of the acetabulum occurring during primary THA, (2) the location of occult fractures of the acetabulum during THA, and (3) risk factors contributing to such occult fractures. Between 2004 and 2013, our institute performed 585 primary THAs (cementless or hybrid) in 494 patients with DICOM pre- and postoperative CT; during the period in question, all patients undergoing THA underwent CT before and after surgery. Preoperative CT images were taken as part of a CT-based three-dimensional templating software and navigation system. Postoperative CT images were taken an average of 1 week after surgery as part of a different protocol to evaluate cup position, restoration of leg length and offset, volume of postoperative hematoma to assess anticoagulation effects after THA, and fractures that were not found on routine postoperative radiographs (which we defined as occult fractures). Patients with a history of prior pelvic osteotomy, trauma, and infection were excluded (88 patients/99 hips); 406 patients (102 males and 304 females; 486 hips) form the basis of this report. The mean age of the patients was 60 ± 11 years, with a mean BMI of 23 ± 4 kg/m 2 . The mean followup of the patients with periprosthetic fracture of the acetabulum was 58 ± 28 months (range, 12-131 months). Potential risk factors for occult acetabular fracture including age, sex, BMI, preoperative diagnosis, additional dome screw fixation, composition and size of each cup, and acetabular design were examined in multivariate analysis. Acetabular component designs were categorized as true hemispheric, peripheral self-locking, and elliptical; during the period in question the indications for each cup design were based on the brand of stem used. Comparison between preoperative and postoperative CT images was done to detect the fractures. Patients with fractures identified during surgery were treated with additional dome screw fixation and a 3-week period of nonweightbearing. Patients with occult fractures in this series did not receive additional treatment as we had confirmed secure fixation of the cup during surgery. Occult fractures occurred in 41 hips (8.4%); periprosthetic fractures of the acetabulum were seen during surgery in an additional two hips (0.4%). The superolateral wall was the most frequent location for occult fractures of the acetabulum. After controlling for relevant confounding variables, only the use of peripheral self-locking cups was associated with an increased risk of occult fracture (odds ratio [OR], 2.6 compared with hemispheric cups; 95% CI, 1.2-5.6; p < 0.05). All patients with occult fractures showed bone ingrowth fixation at the final followup, without any additional surgical intervention. Periprosthetic occult fractures of the acetabulum may occur relatively frequently during press-fit impaction. We observed a higher rate of fractures associated with the use of peripheral self-locking components. Occult acetabular fractures not detected on routine postoperative plain films may be ignored if secure fixation of the cup has been confirmed during the operation. Level III, therapeutic study.

Utilization of Palm Oil Clinker as Cement Replacement Material

PubMed Central

Kanadasan, Jegathish; Abdul Razak, Hashim

2015-01-01

The utilization of waste materials from the palm oil industry provides immense benefit to various sectors of the construction industry. Palm oil clinker is a by-product from the processing stages of palm oil goods. Channelling this waste material into the building industry helps to promote sustainability besides overcoming waste disposal problems. Environmental pollution due to inappropriate waste management system can also be drastically reduced. In this study, cement was substituted with palm oil clinker powder as a binder material in self-compacting mortar. The fresh, hardened and microstructure properties were evaluated throughout this study. In addition, sustainability component analysis was also carried out to assess the environmental impact of introducing palm oil clinker powder as a replacement material for cement. It can be inferred that approximately 3.3% of cement production can be saved by substituting palm oil clinker powder with cement. Reducing the utilization of cement through a high substitution level of this waste material will also help to reduce carbon emissions by 52%. A cleaner environment free from pollutants can be created to ensure healthier living. Certain industries may benefit through the inclusion of this waste material as the cost and energy consumption of the product can be minimized. PMID:28793748

Utilization of Palm Oil Clinker as Cement Replacement Material.

PubMed

Kanadasan, Jegathish; Abdul Razak, Hashim

2015-12-16

The utilization of waste materials from the palm oil industry provides immense benefit to various sectors of the construction industry. Palm oil clinker is a by-product from the processing stages of palm oil goods. Channelling this waste material into the building industry helps to promote sustainability besides overcoming waste disposal problems. Environmental pollution due to inappropriate waste management system can also be drastically reduced. In this study, cement was substituted with palm oil clinker powder as a binder material in self-compacting mortar. The fresh, hardened and microstructure properties were evaluated throughout this study. In addition, sustainability component analysis was also carried out to assess the environmental impact of introducing palm oil clinker powder as a replacement material for cement. It can be inferred that approximately 3.3% of cement production can be saved by substituting palm oil clinker powder with cement. Reducing the utilization of cement through a high substitution level of this waste material will also help to reduce carbon emissions by 52%. A cleaner environment free from pollutants can be created to ensure healthier living. Certain industries may benefit through the inclusion of this waste material as the cost and energy consumption of the product can be minimized.

New Medium for Isolation of Bacteria From Cement Kiln Dust with a Potential to Apply in Bio-Concrete

NASA Astrophysics Data System (ADS)

Alshalif, A. F.; Irwan, J. M.; Othman, N.; Al-Gheethi, A.

2018-04-01

The present study aimed to introduce a new isolation medium named kiln dust medium (KDM) for recovering of bacteria from cement kiln dust with high pH (>pH 11) without the need for nutrients additives. The cement kiln dust samples were collected from five different areas of Cement Industries of Malaysia Berhad (CIMA). The bacterial isolates were recovered on KDM by direct plating technique. The chemical components for all collected samples were identified using X-ray fluorescence (XRF). The primary identification for the bacterial isolates indicated that these bacteria belongs to Bacillus spp. Based on the morphological characteristics. The growth curve of the bacterial strains was monitored using the optical density (OD) with 650 nm wavelength, which in role confirmed that all isolated bacteria had the ability to grow successfully in the proposed medium. The ability of the bacterial strains to grow at high pH reflects their potential in the bio-concrete applications (aerated and non-aerated concrete). These findings indicated that the cement kiln dust samples from Cement Industries represent the most appropriate source for bacteria used in the bioconcrete.

Regional Survey of Structural Properties and Cementation Patterns of Fault Zones in the Northern Part of the Albuquerque Basin, New Mexico - Implications for Ground-Water Flow

USGS Publications Warehouse

Minor, Scott A.; Hudson, Mark R.

2006-01-01

Motivated by the need to document and evaluate the types and variability of fault zone properties that potentially affect aquifer systems in basins of the middle Rio Grande rift, we systematically characterized structural and cementation properties of exposed fault zones at 176 sites in the northern Albuquerque Basin. A statistical analysis of measurements and observations evaluated four aspects of the fault zones: (1) attitude and displacement, (2) cement, (3) lithology of the host rock or sediment, and (4) character and width of distinctive structural architectural components at the outcrop scale. Three structural architectural components of the fault zones were observed: (1) outer damage zones related to fault growth; these zones typically contain deformation bands, shear fractures, and open extensional fractures, which strike subparallel to the fault and may promote ground-water flow along the fault zone; (2) inner mixed zones composed of variably entrained, disrupted, and dismembered blocks of host sediment; and (3) central fault cores that accommodate most shear strain and in which persistent low- permeability clay-rich rocks likely impede the flow of water across the fault. The lithology of the host rock or sediment influences the structure of the fault zone and the width of its components. Different grain-size distributions and degrees of induration of the host materials produce differences in material strength that lead to variations in width, degree, and style of fracturing and other fault-related deformation. In addition, lithology of the host sediment appears to strongly control the distribution of cement in fault zones. Most faults strike north to north-northeast and dip 55? - 77? east or west, toward the basin center. Most faults exhibit normal slip, and many of these faults have been reactivated by normal-oblique and strike slip. Although measured fault displacements have a broad range, from 0.9 to 4,000 m, most are <100 m, and fault zones appear to have formed mainly at depths less than 1,000 m. Fault zone widths do not exceed 40 m (median width = 15.5 m). The mean width of fault cores (0.1 m) is nearly one order of magnitude less than that of mixed zones (0.75 m) and two orders of magnitude less than that of damage zones (9.7 m). Cements, a proxy for localized flow of ancient ground water, are common along fault zones in the basin. Silica cements are limited to faults that are near and strike north to northwest toward the Jemez volcanic field north of the basin, whereas carbonate fault cements are widely distributed. Coarse sediments (gravel and sand) host the greatest concentrations of cement within fault zones. Cements fill some extension fractures and, to a lesser degree, are concentrated along shear fractures and deformation bands within inner damage zones. Cements are commonly concentrated in mixed zones and inner damage zones on one side of a fault and thus are asymmetrically distributed within a fault zone, but cement does not consistently lie on the basinward side of faults. From observed spatial patterns of asymmetrically distributed fault zone cements, we infer that ancient ground-water flow was commonly localized along, and bounded by, faults in the basin. It is apparent from our study that the Albuquerque Basin contains a high concentration of faults. The geometry of, internal structure of, and cement and clay distribution in fault zones have created and will continue to create considerable heterogeneity of permeability within the basin aquifers. The characteristics and statistical range of fault zone features appear to be predictable and consistent throughout the basin; this predictability can be used in ground-water flow simulations that consider the influence of faults.

Cement manufacture and the environment - Part I: Chemistry and technology

USGS Publications Warehouse

Van Oss, H. G.; Padovani, A.C.

2002-01-01

Hydraulic (chiefly portland) cement is the binding agent in concrete and mortar and thus a key component of a country's construction sector. Concrete is arguably the most abundant of all manufactured solid materials. Portland cement is made primarily from finely ground clinker, which itself is composed dominantly of hydraulically active calcium silicate minerals formed through high-temperature burning of limestone and other materials in a kiln. This process requires approximately 1.7 tons of raw materials perton of clinker produced and yields about 1 ton of carbon dioxide (CO2) emissions, of which calcination of limestone and the combustion of fuels each contribute about half. The overall level of CO2 output makes the cement industry one of the top two manufacturing industry sources of greenhouse gases; however, in many countries, the cement industry's contribution is a small fraction of that from fossil fuel combustion by power plants and motor vehicles. The nature of clinker and the enormous heat requirements of its manufacture allow the cement industry to consume a wide variety of waste raw materials and fuels, thus providing the opportunity to apply key concepts of industrial ecology, most notably the closing of loops through the use of by-products of other industries (industrial symbiosis). In this article, the chemistry and technology of cement manufacture are summarized. In a forthcoming companion article (part II), some of the environmental challenges and opportunities facing the cement industry are described. Because of the size and scope of the U.S. cement industry, the analysis relies primarily on data and practices from the United States.

In Vitro Evaluation of Cell Compatibility of Dental Cements Used with Titanium Implant Components.

PubMed

Marvin, Jason C; Gallegos, Silvia I; Parsaei, Shaida; Rodrigues, Danieli C

2018-03-09

To evaluate the biocompatibility of five dental cement compositions after directly exposing human gingival fibroblast (HGF) and MC3T3-E1 preosteoblast cells to cement alone and cement applied on commercially pure titanium (cpTi) specimens. Nanostructurally integrated bioceramic (NIB), resin (R), resin-modified glass ionomer (RMGIC), zinc oxide eugenol (ZOE), and zinc phosphate (ZP) compositions were prepared according to the respective manufacturer's instructions. Samples were prepared in cylindrical Teflon molds or applied over the entire surface of polished cpTi discs. All samples were cured for 0.5, 1, 12, or 24 hours post-mixing. Direct contact testing was conducted according to ISO 10993 by seeding 6-well plates at 350,000 cells/well. Plates were incubated at 37°C in a humidified atmosphere with 5% CO 2 for 24 hours before individually plating samples and cpTi control discs. Plates were then incubated for an additional 24 hours. Microtetrazolium (MTT) cell viability assays were used to measure sample cytotoxicity. For samples that cured for 24 hours prior to direct contact exposure, only NIB and ZP cements when cemented on cpTi demonstrated cell viability percentages above the minimum biocompatibility requirement (≥70%) for both the investigative cell lines. R, RMGIC, and ZOE cements exhibited moderate to severe cytotoxic effects on both cell lines in direct contact and when cemented on cpTi specimens. For HGF cells, ZOE cemented-cpTi specimens exhibited significantly decreased cytotoxicity, whereas RMGIC cemented-cpTi specimens exhibited significantly increased cytotoxicity. Despite previous studies that showed enhanced cpTi corrosion activity for fluoride-containing compositions (NIB and ZP), there was no significant difference in cytotoxicity between cement alone and cemented-cpTi. In general, the MC3T3-E1 preosteoblast cells were more sensitive than HGF cells to cement composition. Ultimately, cement composition played a significant role in maintaining host cell compatibility. Results of this work help illustrate the impact of different cement formulations on host cell health and emphasize the need for understanding material properties when selecting certain formulations of dental cements, which can ultimately influence the survival of dental implant systems. © 2018 by the American College of Prosthodontists.

Protrusio acetabuli in sickle-cell anemia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinez, S.; Apple, J.S.; Baber, C.

1984-04-01

Of 155 adults with sickle-cell anemia (SS, SC), radiographs of the pelvis or hip demonstrated protrusio acetabuli on at least one side in 14 (3 men and 11 women), as indicated by projection of the acetabular line medial to the ilio-ischial line. All 14 patients had bone changes attributable to sickle-cell anemia, including marrow hyperplasia and osteonecrosis; however, the severity of femoral or acetabular osteonecrosis did not appear directly related to the protrusion. The authors conclude that sickle-cell anemia can predispose to development of protrusio acetabuli.

Extended fatigue life of a catalyst-free self-healing acrylic bone cement using microencapsulated 2-octyl cyanoacrylate

PubMed Central

Brochu, Alice B.W.; Matthys, Oriane B.; Craig, Stephen L.; Reichert, William M.

2014-01-01

The tissue adhesive 2-octyl cyanoacrylate (OCA) was encapsulated in polyurethane microshells and incorporated into bone cement to form a catalyst free, self-healing bone cement comprised of all clinically approved components. The bending strength, modulus, and fatigue lifetime were investigated in accordance with ASTM and ISO standards for the testing of PMMA bone cement. The bending strength of bone cement specimens decreased with increasing wt% capsules content for capsules without or with OCA, with specimens of < 5 wt% capsule content showing minimal effect. In contrast, bone cement bending modulus was insensitive to capsule content. Load controlled fatigue testing was performed in air at room temperature on capsule free bone cement (0 wt%), bone cement with 5 wt% OCA-free capsules (5 wt% No OCA), and 5 wt% OCA-containing capsules (5 wt% OCA). Specimens were tested at a frequency of 5 Hz at maximum stresses of 90%, 80%, 70% and 50% of each specimen's bending strength until failure. The 5 wt% OCA exhibited significant self-healing at 70% and 50% of its reference strength (p < 0.05). Fatigue testing of all three specimen types in air at 22 MPa (50% of reference strength of the 5 wt% OCA specimens) showed that the cycles to failure of OCA-containing specimens was increased by two-fold compared to the OCA-free and capsule-free specimens. This study represents the first demonstration of dynamic, catalyst-free self-healing in a biomaterial formulation. PMID:24825796

Effect of storage temperature and equilibration time on polymethyl methacrylate (PMMA) bone cement polymerization in joint replacement surgery.

PubMed

Koh, Bryan T H; Tan, J H; Ramruttun, Amit Kumarsing; Wang, Wilson

2015-11-17

In cemented joint arthroplasty, the handling characteristics (doughing, working, and setting times) of polymethyl methacrylate (PMMA) bone cement is important as it determines the amount of time surgeons have to optimally position an implant. Storage conditions (temperature and humidity) and the time given for PMMA cement to equilibrate to ambient operating theater (OT) temperatures are often unregulated and may lead to inconsistencies in its handling characteristics. This has not been previously studied. Hence, the purpose of this study was to investigate the effect of storage temperatures on the handling characteristics of PMMA cement and the duration of equilibration time needed at each storage temperature to produce consistent and reproducible doughing, setting, and working times. SmartSet® HV cement was stored at three different controlled temperatures: 20 °C (control), 24 °C, and 28 °C for at least 24 h prior to mixing. The cement components were then brought into a room kept at 20 °C and 50 % humidity. Samples were allowed to equilibrate to ambient conditions for 15, 30, 45, and 60 min. The cement components were mixed and the dough time, temperature-versus-time curve (Lutron TM-947SD, Lutron Electronics, Inc., Coopersburg, PA), and setting time were recorded. Analysis was performed using the two-way ANOVA test (IBM SPSS Statistics V.22). At 20 °C (control) storage temperature, the mean setting time was 534 ± 17 s. At 24 °C storage temperature, the mean setting time was 414 ± 6 s (p < 0.001*) with 15 min of equilibration, 446 ± 11 s (p < 0.001*) with 30 min of equilibration, 501 ± 12 s (p < 0.001*) with 45 min of equilibration, and 528 ± 15 (p > 0.05) with 60 min of equilibration. At 28 °C storage temperature, the mean setting time was 381 ± 8 s (p < 0.001*) with 15 min of equilibration, 432 ± 30 s (p < 0.001*) with 30 min of equilibration, 487 ± 9 (p < 0.001*) with 45 min of equilibration, and 520 ± 16 s (p > 0.05) with 60 min of equilibration. This study reflects the extent to which storage temperatures and equilibration times can potentially affect the handling characteristics of PMMA cement. We recommend institutions to have a well-regulated temperature and humidity-controlled facility for storage of bone cements and a protocol to standardize the equilibration time of cements prior to use in the OT to improve consistency and reproducibility of the handling characteristics of PMMA cement.

Finite Element Analysis of Surface Residual Stress in Functionally Gradient Cemented Carbide Tool

NASA Astrophysics Data System (ADS)

Su, Chuangnan; Liu, Deshun; Tang, Siwen; Li, Pengnan; Qiu, Xinyi

2018-03-01

A component distribution model is proposed for three-component functionally gradient cemented carbide (FGCC) based on electron probe microanalysis results obtained for gradient layer thickness, microstructure, and elemental distribution. The residual surface stress of FGCC-T5 tools occurring during the fabrication process is analyzed using an ANSYS-implemented finite element method (FEM) and X-ray diffraction. A comparison of the experimental and calculated values verifies the feasibility of using FEM to analyze the residual surface stress in FGCC-T5 tools. The effects of the distribution index, geometrical shape, substrate thickness, gradient layer thickness, and position of the cobalt-rich layer on residual surface stress are studied in detail.

Analysis of Femoral Components of Cemented Total Hip Arthroplasty

NASA Astrophysics Data System (ADS)

Singh, Shantanu; Harsha, A. P.

2016-10-01

There have been continuous on-going revisions in design of prosthesis in Total Hip Arthroplasty (THA) to improve the endurance of hip replacement. In the present work, Finite Element Analysis was performed on cemented THA with CoCrMo trapezoidal, CoCrMo circular, Ti6Al4V trapezoidal and Ti6Al4V circular stem. It was observed that cross section and material of femoral stem proved to be critical parameters for stress distribution in femoral components, distribution of interfacial stress and micro movements. In the first part of analysis, designs were investigated for micro movements and stress developed, for different stem materials. Later part of the analysis focused on investigations with respect to different stem cross sections. Femoral stem made of Titanium alloy (Ti6Al4V) resulted in larger debonding of stem at cement-stem interface and increased stress within the cement mantle in contrast to chromium alloy (CoCrMo) stem. Thus, CoCrMo proved to be a better choice for cemented THA. Comparison between CoCrMo femoral stem of trapezium and circular cross section showed that trapezoidal stem experiences lesser sliding and debonding at interfaces than circular cross section stem. Also, trapezium cross section generated lower peak stress in femoral stem and cortical femur. In present study, femur head with diameter of 36 mm was considered for the analysis in order to avoid dislocation of the stem. Also, metallic femur head was coupled with cross linked polyethylene liner as it experiences negligible wear compared to conventional polyethylene liner and unlike metallic liner it is non carcinogenic.

Evaluating the accuracy of wear formulae for acetabular cup liners.

PubMed

Wu, James Shih-Shyn; Hsu, Shu-Ling; Chen, Jian-Horng

2010-02-01

This study proposes two methods for exploring the wear volume of a worn liner. The first method is a numerical method, in which SolidWorks software is used to create models of the worn out regions of liners at various wear directions and depths. The second method is an experimental one, in which a machining center is used to mill polyoxymethylene to manufacture worn and unworn liner models, then the volumes of the models are measured. The results show that the SolidWorks software is a good tool for presenting the wear pattern and volume of a worn liner. The formula provided by Ilchmann is the most suitable for computing liner volume loss, but is not accurate enough. This study suggests that a more accurate wear formula is required. This is crucial for accurate evaluation of the performance of hip components implanted in patients, as well as for designing new hip components.

Digital templating for THA: a simple computer-assisted application for complex hip arthritis cases.

PubMed

Hafez, Mahmoud A; Ragheb, Gad; Hamed, Adel; Ali, Amr; Karim, Said

2016-10-01

Total hip arthroplasty (THA) is the standard procedure for end-stage arthritis of the hip. Its technical success relies on preoperative planning of the surgical procedure and virtual setup of the operative performance. Digital hip templating is one methodology of preoperative planning for THA which requires a digital preoperative radiograph and a computer with special software. This is a prospective study involving 23 patients (25 hips) who were candidates for complex THA surgery (unilateral or bilateral). Digital templating is done by radiographic assessment using radiographic magnification correction, leg length discrepancy and correction measurements, acetabular component and femoral component templating as well as neck resection measurement. The overall accuracy for templating the stem implant's exact size is 81%. This percentage increased to 94% when considering sizing within 1 size. Digital templating has proven effective, reliable and essential technique for preoperative planning and accurate prediction of THA sizing and alignment.

Evaluation of Rapid-Setting Concretes for Airfield Spall Repair

DTIC Science & Technology

1991-04-01

repair concretes for Rapid Runway Repair (RRR). The three were a methyl methacrylate binder (Silikal RI7AF), a magnesium phosphate mortar mix (Set-45...reld Methyl methacrylate Rapid-setting 82 Blended cement Pavement materials 16. PRICE CODE Magnesium phosphate cement Rapid runway repair Spall repair 17...conditions, and for use during RRR training. Silikal is a methyl methacrylate , which forms a solid mass within minutes after its two components are mixed. It

In vitro Characteristics of a Glass Ionomer Cement

PubMed Central

Driscoll, Colin L. W.; Green, J. Douglas; Beatty, Charles W.; McCaffrey, Thomas V.; Marrs, Christopher D.

1998-01-01

Glass ionomer cements were first described by Wilson and Kent and have been used in dentistry since 1969. It has been recommended for bridging ossicular chain defects, fixation of ossicular chain prosthesis, anchoring of cochlear implants, mastoid obliteration, and repair of tegmen and posterior canal wall defects. The biocompatability and stability of this material over time is vital to its usefulness in neurotologic surgery. The purpose of this study was to assess the stability of a glass ionomer cement in the presence of bacteria and in different pH environments. We demonstrated that bacteria readily adhere to the surface and their presence is associated with accelerated loss of matrix. We found the cement to be susceptible to low pH and to release a visible cloud of debris upon contact with fluid. Calcium concentration in the solution was elevated at all pH levels. Although we are able to demonstrate these findings in vitro the clinical relevance is unclear. There have been several cases of aseptic meningitis possibly due to intracranial release of components of the cement. Until further studies are done use of the cement in contact with cerebral spinal fluid should be avoided. This cement, or a similar material, would be useful in neurotologic surgery but prior to widespread use further testing should be done to assess safety. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 9Figure 10Figure 11 PMID:17171062

Is labral hypotrophy correlated with increased acetabular depth?

PubMed Central

Toft, Felix; Anliker, Elmar; Beck, Martin

2015-01-01

Labral hypertrophy is a distinct feature in hip dysplasia. Occasionally, very small, hypotrophic labra are observed. However, there is no literature concerning this pathology. We investigated if the size of the labrum correlated with any radiologic parameters reflecting the amount of acetabular coverage. It was hypothezised that there is a negative correlation between labrum size and acetabular coverage. Labra were categorized into three groups depending on the relation between length of the articular sided surface and height of bony attachment. Labra with a height:length ratio of 2 were classified as hypotrophic, with a height:length ratio of 1 as normal and with a ratio of 0.5 as hypertrophic. Labral cross-sectional areas (CSA) were measured on radial magnetic resonance imaging-arthrography slices using the measuring tool of the PACS system of 20 hips with hypotrophic labra (group 1), 20 hips with normal labral appearance (group 2) and 10 hips with hypertrophic labra (group 3). These values were then analyzed against following parameters: neck-shaft-angle (NSA), lateral center-edge angle (LCE), acetabular index (AI), femoral extrusion index (FEI) and acetabular retroversion index (ARI). Analyses of variance were used to determine differences in mean values between the three groups. Mean labral CSA differed significantly between all groups (group 1: 12.1 ± 2.9 mm2; group 2: 25.2 ± 6.2 mm2; group 3: 41.1 ± 12.3 mm2; P < 0.001). NSA, LCE, AI and FEI all showed a significant difference between group 3 and 1 or 2. The ARI showed no difference between groups. Stepwise linear regression analyses showed a significant correlation between LCE angle and labral CSA with a corrected R2-value of 0.301. Labral CSA correlates with the LCE. No statistically significant difference between groups 1 and 2 concerning the LCE, AI or FEI could be identified. Nevertheless, group 1 had the highest mean coverage of all groups, hips with hypertrophic labra the lowest. PMID:27011836

The effect of bearing friction torques on the primary stability of press-fit acetabular cups: A novel in vitro method.

PubMed

Alexander, Jahnke; Stefan, Schroeder; Alfonso, Fonseca Ulloa Carlos; Adam, Ahmed Gafar; Alexander, Ishaque Bernd; Markus, Rickert

2018-05-10

Aseptic loosening is the main reason for revision of total hip arthroplasty, and relative micromotions between cementless acetabular cups and bone play an important role regarding their comparatively high loosening rate. Therefore, the aim of the present study was to analyze the influence of resulting frictional torques on the primary stability of press-fit acetabular cups subjected to two different bearing partners. A cementless press-fit cup was implanted in bone-like foam. Primary stability of the cup was analyzed by determining spatial total, translational and rotational interface micromotions by means of an eddy current sensor measuring system. Torque transmission into the cup was realized by three synchronous servomotors considering resultant friction torques based on constant friction for ceramic-on-ceramic (CoC: µ = 0.044; max. resultant torque: 1.5 Nm) and for ceramic-on-polyethylene (CoP: µ = 0.063; max. resultant torque: 1.9 Nm) bearing partners. Rotational micromotion of CoC was 8.99 ± 0.85µm and of CoP 13.39 ± 1.43µm. Translational micromotion of CoC was 29.93 ± 1.44µm and of CoP 39.91 ± 2.25µm. Maximum total relative micromotions were 37.10 ± 1.07µm for CoC and 51.64 ± 2.18µm for CoP. Micromotions resulting from CoC were statistically lower than those resulting from CoP (p < 0.05). The described 3D-measuring set-up offers a novel in vitro method of measuring primary stability of acetabular cups. We can therefore conclude, that primary stability of acetabular cup systems can be observed using either the lower friction curve (CoC) or the higher friction curve (CoP). In future studies different cup designs or cup fixation mechanisms may be tested and compared in vitro and assessed prior to implantation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Cement-based materials' characterization using ultrasonic attenuation

NASA Astrophysics Data System (ADS)

Punurai, Wonsiri

The quantitative nondestructive evaluation (NDE) of cement-based materials is a critical area of research that is leading to advances in the health monitoring and condition assessment of the civil infrastructure. Ultrasonic NDE has been implemented with varying levels of success to characterize cement-based materials with complex microstructure and damage. A major issue with the application of ultrasonic techniques to characterize cement-based materials is their inherent inhomogeneity at multiple length scales. Ultrasonic waves propagating in these materials exhibit a high degree of attenuation losses, making quantitative interpretations difficult. Physically, these attenuation losses are a combination of internal friction in a viscoelastic material (ultrasonic absorption), and the scattering losses due to the material heterogeneity. The objective of this research is to use ultrasonic attenuation to characterize the microstructure of heterogeneous cement-based materials. The study considers a real, but simplified cement-based material, cement paste---a common bonding matrix of all cement-based composites. Cement paste consists of Portland cement and water but does not include aggregates. First, this research presents the findings of a theoretical study that uses a set of existing acoustics models to quantify the scattered ultrasonic wavefield from a known distribution of entrained air voids. These attenuation results are then coupled with experimental measurements to develop an inversion procedure that directly predicts the size and volume fraction of entrained air voids in a cement paste specimen. Optical studies verify the accuracy of the proposed inversion scheme. These results demonstrate the effectiveness of using attenuation to measure the average size, volume fraction of entrained air voids and the existence of additional larger entrapped air voids in hardened cement paste. Finally, coherent and diffuse ultrasonic waves are used to develop a direct relationship between attenuation and water to cement (w/c) ratio. A phenomenological model based on the existence of fluid-filled capillary voids is used to help explain the experimentally observed behavior. Overall this research shows the potential of using ultrasonic attenuation to quantitatively characterize cement paste. The absorption and scattering losses can be related to the individual microstructural elements of hardened cement paste. By taking a fundamental, mechanics-based approach, it should be possible to add additional components such as scattering by aggregates or even microcracks in a systematic fashion and eventually build a realistic model for ultrasonic wave propagation study for concrete.

Feasibility of disposing waste glyphosate neutralization liquor with cement rotary kiln.

PubMed

Bai, Y; Bao, Y B; Cai, X L; Chen, C H; Ye, X C

2014-08-15

The waste neutralization liquor generated during the glyphosate production using glycine-dimethylphosphit process is a severe pollution problem due to its high salinity and organic components. The cement rotary kiln was proposed as a zero discharge strategy of disposal. In this work, the waste liquor was calcinated and the mineralogical phases of residue were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The mineralogical phases and the strength of cement clinker were characterized to evaluate the influence to the products. The burnability of cement raw meal added with waste liquor and the calorific value of waste liquor were tested to evaluate the influence to the thermal state of the kiln system. The results showed that after the addition of this liquor, the differences of the main phases and the strength of cement clinker were negligible, the burnability of raw meal was improved; and the calorific value of this liquor was 6140 J/g, which made it could be considered as an alternative fuel during the actual production. Copyright © 2014 Elsevier B.V. All rights reserved.

Is transverse acetabular ligament an anatomical landmark to reliably orient the cup in primary total hip arthroplasty?

PubMed

Viste, A; Chouteau, J; Testa, R; Chèze, L; Fessy, M-H; Moyen, B

2011-05-01

Accurate positioning of the acetabular cup in primary total hip arthroplasty is critical to decrease the rate of dislocation. Inaccurate orientation of the cup is the most common error during this procedure. Target acetabular orientation is still controversial. An original study found a dislocation rate of 0.6% when the cup was aligned with the transverse acetabular ligament (TAL). TAL is a patient-specific anatomical landmark and a tool for cup orientation. Eight cadaveric pelves (14 hips included for study) were harvested in toto at our research laboratory. Anatomical versions of the TAL, labrum and horns were measured in relation to the anterior pelvic plane. A navigator sensor and an optoelectronic device (Motion Analysis™) were used. Anatomical versions of the TAL, horns and labrum averaged 1.9° (range, -8° to +13.3°), 3° (range, -12.2° to 14°), and 26.3° (range, 17.4° to 41.8°), respectively. To our knowledge, this is the first study to report the orientation of the periacetabular soft-tissues. TAL anteversion was outside the safe zone described by Lewinnek, while labrum anteversion was within this safe-zone. We discuss the reference used, Lewinnek's safe zone, and functional orientation of the implants. Lewinnek's safe-zone does not seem to be valid. The TAL seems to be a specific reference for each patient but its reliability must still be confirmed as an adequate reference for positioning the cup in total hip arthroplasty. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

A case report of the management and the outcome of a complete epiphyseal separation and dislocation with left anterior column fracture of the acetabulum.

PubMed

Palencia, Jesús; Alfayez, Saud; Serro, Firas; Alqahtani, Jamal; Alharbi, Hani; Alhinai, Hamed

2016-01-01

Femoral head and neck fractures in children are uncommon, accounting for fewer than 1% of all pediatric fractures and fewer than 8% of all hip fractures. Furthermore, traumatic transphyseal hip fracture is rare to present in daily practice especially when associated with an acetabular fracture. A twelve years old boy, not known to have any chronic illnesses, presented to the emergency department as a case of polytrauma after a road traffic accident. Signs of left hip dislocation were discovered upon physical examination. X-rays and CT scans, revealed a complete transphyseal posterior dislocation and a left anterior column fracture of the acetabulum with a minimal displacement. Within five hours, the patient underwent open reduction and internal fixation by two cannulated screws. The acetabular fracture was managed conservatively. After six months, there were clear signs of osteonecrosis of the femoral head. A high-energy trauma in children and adolescents can lead to simultaneous epiphyseal and acetabular fractures which are associated with a poor prognosis. The age seems to play a role as patients older than ten years have a higher risk of developing AVN after sustaining a hip dislocation regardless of the time of intervention. Epiphyseal fracture with dislocation of the femoral head is rare among children and adolescents, especially when associated with an acetabular fracture. AVN in such cases can develop, and it represents a challenge to orthopedic surgeons due to the poor prognosis and the future functional limitations of the joint. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

[Modified PemberSal osteotomy technique with lyophilized human allograft].

PubMed

Druschel, C; Heck, K; Kraft, C; Placzek, R

2016-12-01

PemberSal osteotomy to improve femoral head coverage by rotating the acetabular roof ventrally and laterally. Insufficient coverage of the femoral head, and can be combined with other surgical procedures such as femoral intertrochanteric varus-derotation osteotomy and open reduction for developmental dysplasia and dislocation of the hip or to improve sphericity and containment in Legg-Calvé-Perthes disease. This specific acetabuloplasty can only be performed in patients with an open epiphyseal growth-plate. Increased bleeding tendency (e.g., inherited or iatrogenic); elevated anesthetic risk such as in cerebral palsy, arthrogryposis multiplex congenital, trisomies; syndromes require explicit interdisciplinary clarification to reduce perioperative risks; infections as in other elective surgeries; diseases/deformities making postoperative spica casting impossible or impractical (e.g., deformities of spinal cord or urogenital system, hernias requiring treatment); closed epiphyseal plate requires complex three-dimensional corrections of the acetabular roof (e.g., triple/periacetabular osteotomy). Osteotomy from the iliac bone to the posterior ilioischial arm of the epiphyseal growth-plate cartilage; controlled fracture of the cancellous bone without breaking the medial cortex of the iliac bone for ventrocaudal rotation of the acetabular roof. To refill and stabilize the osteotomy site, an allogenic bone-wedge is interponated and secured by a resorbable screw or kirschner wire. This method also allows more complex reconstructions of the acetabular roof, e.g., by including the pseudo-cup in a modified Rejholec technique. A spica cast is applied to immobilize the hip for 6 weeks. Afterwards physiotherapy can be performed under weight-bearing as tolerated. Radiographic check-ups every 6 months.

Variation in Treatment of Displaced Geriatric Acetabular Fractures Among 15 Level-I Trauma Centers.

PubMed

Manson, Theodore T; Reider, Lisa; OʼToole, Robert V; Scharfstein, Daniel O; Tornetta, Paul; Gary, Joshua L

2016-09-01

To document the initial treatment of displaced acetabular fractures among older adults across multiple trauma centers and to investigate the factors that influence the decision to operate and the choice of operative procedure [open reduction internal fixation (ORIF) vs. total hip arthroplasty (THA)]. Retrospective observational study. Fifteen US level-I trauma centers participating in the Major Extremity Trauma Research Consortium. Overall, 269 patients aged 60 years or older admitted for the treatment of a displaced acetabular fracture. None. Treatment. Sixty percent of fractures (n = 162) were treated operatively. Younger age (<80 years), injury from high-energy mechanism, fractures with femoral head impaction, and fractures without hip congruency were significantly associated with receiving operative treatment (P < 0.05). Significant site variation in operative versus nonoperative treatment occurred even after accounting for these factors (P = 0.0044). Among operatively treated patients, 88% (n = 142) received ORIF and 12% (n = 20) received THA as the initial treatment. Women were more likely to be treated with initial THA compared with men; of the known risk factors for poor outcomes with ORIF (ie, dome or roof impaction, femoral head impaction, or posterior wall involvement), only dome impaction was significantly associated with receiving initial THA (P < 0.05). Currently, no treatment guidelines exist for acetabular fractures in older adults, which likely explains the significant site variation in operative versus nonoperative treatment. This study identifies patient and injury factors that drive treatment decisions, which will be important in planning and designing future trials needed to determine the best treatment for these fractures.

Radiological findings for hip dysplasia at skeletal maturity. Validation of digital and manual measurement techniques.

PubMed

Engesæter, Ingvild Øvstebø; Laborie, Lene Bjerke; Lehmann, Trude Gundersen; Sera, Francesco; Fevang, Jonas; Pedersen, Douglas; Morcuende, José; Lie, Stein Atle; Engesæter, Lars Birger; Rosendahl, Karen

2012-07-01

To report on intra-observer, inter-observer, and inter-method reliability and agreement for radiological measurements used in the diagnosis of hip dysplasia at skeletal maturity, as obtained by a manual and a digital measurement technique. Pelvic radiographs from 95 participants (56 females) in a follow-up hip study of 18- to 19-year-old patients were included. Eleven radiological measurements relevant for hip dysplasia (Sharp's, Wiberg's, and Ogata's angles; acetabular roof angle of Tönnis; articulo-trochanteric distance; acetabular depth-width ratio; femoral head extrusion index; maximum teardrop width; and the joint space width in three different locations) were validated. Three observers measured the radiographs using both a digital measurement program and manually in AgfaWeb1000. Inter-method and inter- and intra-observer agreement were analyzed using the mean differences between the readings/readers, establishing the 95% limits of agreement. We also calculated the minimum detectable change and the intra-class correlation coefficient. Large variations among different radiological measurements were demonstrated. However, the variation was not related to the use of either the manual or digital measurement technique. For measurements with greater absolute values (Sharp's angle, femoral head extrusion index, and acetabular depth-width ratio) the inter- and intra-observer and inter-method agreements were better as compared to measurements with lower absolute values (acetabular roof angle, teardrop and joint space width). The inter- and intra-observer variation differs notably across different radiological measurements relevant for hip dysplasia at skeletal maturity, a fact that should be taken into account in clinical practice. The agreement between the manual and digital methods is good.

Acetabular labral tears with underlying chondromalacia: a possible association with high-level running.

PubMed

Guanche, Carlos A; Sikka, Robby S

2005-05-01

The use of hip arthroscopy has helped delineate intra-articular pathology and has enabled clinicians to further elucidate the factors responsible for injuries, such as running. The subtle development of degenerative changes may be a result of repetitive impact loading associated with this sport. This study presents a population of runners with common pathologic acetabular changes. Case series. Eight high-level runners with an average age of 36 years (range, 19 to 45 years) were seen for complaints of increasing hip pain with running without any history of macrotrauma. All of the patients had either run several marathons (4), were triathletes (1), Olympic middle distance runners (1), or had run more than 10 miles per week for longer than 5 years (2). Plain radiographic analysis revealed no degenerative changes and an average center-edge (CE) angle of 36.7 degrees (range, 28 degrees to 44 degrees). All patients underwent hip arthroscopy with labral debridement. In 6 patients (75%), a chondral injury of the acetabular cartilage underlying the labral tear was noted. In addition, 3 patients had ligamentum teres disruptions. It is possible that the development of these tears is the result of subtle instability, which may be exacerbated by running, eventually leading to labral tearing and possible ligamentum teres disruption. While perhaps concurrently, subtle acetabular dysplasia may play a role. Although this study does not confirm an association between running and the development of labral tears or chondral lesions in the hip, it certainly questions whether there is an injury pattern common to this population, a "runner's hip." Level IV.

Obstacles to reduction in infantile developmental dysplasia of the hip.

PubMed

Studer, K; Williams, N; Studer, P; Baker, M; Glynn, A; Foster, B K; Cundy, P J

2017-10-01

Identification of anatomical structures that block -reduction in developmental dysplasia of the hip (DDH) is -important for the management of this challenging condition. Obstacles to reduction seen on arthrogram are well-known. However, despite the increasing use of MRI in the assessment of adequacy of reduction in DDH, the interpretation of MRI patho-anatomy is ill-defined with a lack of relevant literature to guide clinicians. This is a retrospective analysis of the MRI of patients with DDH treated by closed reduction over a five-year period (between 2009 and 2014). Neuromuscular and genetic disorders were excluded. Each MRI was analysed by two orthopaedic surgeons and a paediatric musculoskeletal radiologist to identify the ligamentum teres, pulvinar, transverse acetabular ligament (TAL), capsule, labrum and acetabular roof cartilage hypertrophy. Inter- and intraobserver reliability was calculated. The minimum follow-up was 12 months. A total of 29 patients (38 hips) underwent closed reduction for treatment of DDH. Eight hips showed persistent subluxation on post-operative MRI. Only three of these eight hips showed an abnormality on arthrogram. The pulvinar was frequently interpreted as 'abnormal' on MRI. The main obstacles identified on MRI were the ligamentum teres (15.8%), labrum (13.1%) and acetabular roof cartilage hypertrophy (13.2%). The inter-rater reliability was good for TAL, capsule and pulvinar; moderate for ligamentum teres and labrum; and poor for hypertrophied cartilage. The labrum, ligamentum teres and acetabular roof cartilage hypertrophy are the most important structures seen on MRI preventing complete reduction of DDH. Focused interpretation of these structures may assist in the management of DDH.

Is the evaluation of the anterior inferior iliac spine (AIIS) in the AP pelvis possible? Analysis of conventional X-rays and 3D-CT reconstructions.

PubMed

Krueger, David R; Windler, Markus; Geßlein, Markus; Schuetz, Michael; Perka, Carsten; Schroeder, Joerg H

2017-07-01

A hypertrophic AIIS has been identified as a cause for extraarticular hip impingement and is classified according to Hetsroni using 3D-CT reconstructions. The role of the conventional AP pelvis X-ray, which is the first standard imaging step for the evaluation of hip pain, has not been investigated yet. AP pelvis X-rays and 3D-CT reconstructions of patients were evaluated regarding their morphology of the AIIS. The conventional X-rays were categorized into three groups according to the projection of the AIIS: above (A) or below (B) the acetabular sourcil or even exceeding the anterior acetabular rim (C). They were compared to the morphologic types in the 3D-CT reconstruction (Hetsroni type I-III). Ninety patients with an equal distribution of type A, B or C projection in the AP pelvis were evaluated and compared to the morphology in the 3D-CT reconstruction. The projection of the AIIS below the acetabular sourcil (B + C) showed only moderate sensitivity (0.76) and specificity (0.64) for a hypertrophic AIIS (Hetsroni type II + III), but if the AIIS exceeds the anterior rim, all cases showed a hypertrophic AIIS in the 3D-CT reconstructions (Hetsroni type II + III). Distinct differentiation of the AIIS morphology in the AP pelvis is not possible, but the projection of the AIIS below the anterior acetabular rim represented a hypertrophic AIIS in all cases and should, therefore, be critically investigated for a relevant AIIS impingement.

[Acetabular anteversion angle of the hip in the Mexican adult population measured with computed tomography].

PubMed

Rubalcava, J; Gómez-García, F; Ríos-Reina, J L

2012-01-01

Knowledge of the radiogrametric characteristics of a specific skeletal segment in a healthy population is of the utmost clinical importance. The main justification for this study is that there is no published description of the radiogrametric parameter of acetabular anteversion in a healthy Mexican adult population. A prospective, descriptive and cross-sectional study was conducted. Individuals of both genders older than 18 years and orthopedically healthy were included. They underwent a two-dimensional axial tomographic study of both hips to measure the acetabular anteversion angles. The statistical analysis consisted of obtaining central trend and scatter measurements. A multivariate analysis of variance (ANOVA) and statistical significance were performed. 118 individuals were studied, 60 males and 58 females, with a mean age of 47.7 +/- 16.7, and a range of 18-85 years. The anteversion of the entire group was 18.6 degrees + 4.1 degrees. Anteversion in males was 17.3 degrees +/- 3.5 degrees (10 degrees - 25 degrees) and in females 19.8 degrees +/- 4.7 degrees (10 degrees - 31 degrees). There were no statistically significant differences (p < or = 0.05) in right and left anteversion in the entire group. However, there were statistically significant differences (p > or = 0.005) both in the right and left sides when males and females were compared. Our study showed that there are great variations in the anteversion ranges of a healthy population. When our results are compared with those published by other authors the mean of most measurements exceeds 15 degrees. This should be useful to make therapeutic decisions that involve acetabular anteversion.

Computer-aided designed, three dimensional-printed hemipelvic prosthesis for peri-acetabular malignant bone tumour.

PubMed

Wang, Baichuan; Hao, Yongqiang; Pu, Feifei; Jiang, Wenbo; Shao, Zengwu

2018-03-01

Prosthetic reconstruction may be a promising treatment for peri-acetabular malignant bone tumour; however, it is associated with a high complication rate. Therefore, prosthetic design and approach of prosthetic reconstruction after tumour resection warrant study. We retrospectively analyzed 11 patients with peri-acetabular malignant bone tumours treated by personalized 3D-printed hemipelvic prostheses after en bloc resection between 2015 and 2016. Pre-operative and post-operative pain at rest was assessed according to a 10-cm VAS score. The results of functional improvement were evaluated using the MSTS-93 score at the final follow-up. We also analyzed tumour recurrence, metastases, and complications associated with the reconstruction procedure. All patients were observed for six to 24 months with an average follow-up of 15.5 months. One patient had occasional pain of the involved hip at the final follow-up (VAS, pre vs. post 8 months: 3 vs. 2). The mean MSTS-93 score was 19.2 (range, 13-25). Hip dislocation was detected in two patients, while delayed wound healing occurred in one patient. One patient with mesenchymal chondrosarcoma had a left iliac bone metastasis. Local tumour recurrence was not observed. Reconstruction of bony defect after tumour resection using personalized 3D-printed hemipelvic prostheses can obtain acceptable functional results without severe complications. Based on previous reports and our results, we believe that reconstruction arthroplasty using 3D-printed hemipelvic prostheses will provide a promising alternative for those patients with peri-acetabular malignant bone tumours. Level IV, therapeutic study.

R3 Cup Does Not Have a High Failure Rate in Conventional Bearings: A Minimum of 5-Year Follow-Up.

PubMed

Teoh, Kar H; Whitham, Robert D J; Golding, David M; Wong, Jenny F; Lee, Paul Y F; Evans, Aled R

2018-02-01

The R3 cementless acetabular system was first marketed in Australia and Europe in 2007. Previous papers have shown high failure rates of the R3 cup with up to 24% with metal-on-metal bearing. There are currently no medium term clinical results on this cup. The aim of the study is to review our results of the R3 acetabular cup with conventional bearings with a minimum of 5-year follow-up. Patients who were implanted with the R3 acetabular cup were identified from our center's arthroplasty database. A total of 293 consecutive total hip arthroplasties were performed in 286 patients. The primary outcome was revision. The secondary outcomes were the Oxford Hip Scores (OHS) and radiographic evaluation. The mean age of the patients was 69.4 years. The mean preoperative OHS was 23 (range 10-34) and the mean OHS was 40 (range 33-48) at the final follow-up. Radiological evaluation showed an excellent ARA score in all patients at 5 years. None of the R3 cups showed osteolysis at the final follow-up. There were 3 revisions in our series, of which 2 R3 cups were revised. The risk of revision was 1.11% at 5 years. Our experience of using the R3 acetabular system with conventional bearings showed high survivorship and is consistent with the allocated Orthopaedic Data Evaluation Panel rating of 5A* as rated in 2015 in the United Kingdom. Copyright © 2017 Elsevier Inc. All rights reserved.

Lateral Compression-I Pelvic Ring Injury: Not Benign to the Developing Fetus.

PubMed

Weinlein, John C; Mashru, Rakesh P; Perez, Edward A; Johnson, Sara E

2018-02-01

To determine whether certain patterns of pelvic ring injury are associated with more frequent intrauterine fetal demise (IUFD). Retrospective review. Level 1 trauma center. Of 44 pregnant patients with pelvic and/or acetabular fractures, 40 had complete records that allowed determination of fetal viability. χ2 tests were used for categorical variables (Fisher exact tests when expected cell counts were fewer than 5), and t tests were used for continuous variables. Fetal or maternal death. Sixteen patients had isolated acetabular fractures, 25 had isolated pelvic ring injuries, and 3 had acetabular fractures with concomitant pelvic ring injuries. Maternal and fetal mortality were 2% and 40%, respectively. No patients with isolated acetabular fractures experienced IUFD, compared with 68% (15/22) of those with isolated pelvic ring injuries (P < 0.0001). Eight (53%) of 15 IUFDs were associated with lateral compression (LC)-I pelvic ring injuries (Orthopaedic Trauma Association/Arbeitsgemeinschaft für Osteosynthesefragen 61-B2). Of the 13 LC-I pelvic ring injuries, 8 (62%) resulted in IUFD. Pelvic ring stability, Young-Burgess classification, and operative treatment were not associated with IUFD. Maternal Glasgow Coma Scale (average 13.2) and Injury Severity Score (average 18.2) at admission were predictive of IUFD. The most frequent pelvic fractures in gravid trauma patients are LC-I. Although the rate of maternal mortality was low, the risk of IUFD was quite high (40%). LC-I pelvic ring injuries often had catastrophic outcomes, with IUFD in 62% of cases. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Experiment and simulation study on the effects of cement minerals on the water-rock-CO2 interaction during CO2 geological storage

NASA Astrophysics Data System (ADS)

Liu, N.; Cheng, J.

2016-12-01

The CO2 geological storage is one of the most promising technology to mitigate CO2 emission. The fate of CO2 underground is dramatically affected by the CO2-water-rock interaction, which are mainly dependent on the initial aquifer mineralogy and brine components. The cement minerals are common materials in sandstone reservoir but few attention has been paid for its effects on CO2-water-rock interaction. Five batch reactions, in which 5% cement minerals were assigned to be quartz, calcite, dolomite, chlorite and Ca-montmorillonite, respectively, were conducted to understanding the cement minerals behaviors and its corresponding effects on the matrix minerals alterations during CO2 geological storage. Pure mineral powders were selected to mix and assemble the 'sandstone rock' with different cement components meanwhile keeping the matrix minerals same for each group as 70% quartz, 20% K-feldspar and 5% albite. These `rock' reacted with 750ml deionized water and CO2 under 180° and 18MPa for 15 days, during which the water chemistry evolution and minerals surface micromorphology changes has been monitored. The minerals saturation indexes calculation and phase diagram as well as the kinetic models were made by PHREEQC to uncover the minerals reaction paths. The experiment results indicated that the quartz got less eroded, on the contrary, K-feldspar and albite continuously dissolved to favor the gibbsite and kaolinite precipitations. The carbonates cement minerals quickly dissolved to reach equilibrium with the pH buffered and in turn suppressed the alkali feldspar dissolutions. No carbonates minerals precipitations occurred until the end of reactions for all groups. The simulation results were basically consistent with the experiment record but failed to simulate the non-stoichiometric reactions and the minerals kinetic rates seemed underestimated at the early stage of reactions. The cement minerals significantly dominated the reaction paths during CO2 geological storage and its effects on the CO2-water-rock interaction should be focused no matter for the benefit of injection sustainability or carbon sequestration capability. And more cement minerals such as ankerite should be included and the reservoir quality changes should also be taken consideration in the further study.

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

...-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a...-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the...

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

...-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a...-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the...

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

...-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a...-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the...

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

...-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a...-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the...

Blooming gelatin: an individual additive for enhancing nanoapatite precipitation, physical properties, and osteoblastic responses of nanostructured macroporous calcium phosphate bone cements

PubMed Central

Orshesh, Ziba; Hesaraki, Saeed; Khanlarkhani, Ali

2017-01-01

In recent years, there has been a great interest in using natural polymers in the composition of calcium phosphate bone cements to enhance their physical, mechanical, and biological performance. Gelatin is a partially hydrolyzed form of collagen, a natural component of bone matrix. In this study, the effect of blooming gelatin on the nanohydroxyapatite precipitation, physical and mechanical properties, and cellular responses of a calcium phosphate bone cement (CPC) was investigated. Various concentrations of blooming gelatin (2, 5, and 8 wt.%) were used as the cement liquid and an equimolar mixture of tetracalcium phosphate and dicalcium phosphate was used as solid phase. The CPC without any gelatin additive was also evaluated as a control group. The results showed that gelatin accelerated hydraulic reactions of the cement paste, in which the reactants were immediately converted into nanostructured apatite precipitates after hardening. Gelatin molecules induced 4%–10% macropores (10–300 μm) into the cement structure, decreased initial setting time by ~190%, and improved mechanical strength of the as-set cement. Variation in the above-mentioned properties was influenced by the gelatin concentration and progressed with increasing the gelatin content. The numbers of the G-292 osteoblastic cells on gelatin-containing CPCs were higher than the control group at entire culture times (1–14 days), meanwhile better alkaline phosphatase (ALP) activity was determined using blooming gelatin additive. The observation of cell morphologies on the cement surfaces revealed an appropriate cell attachment with extended cell membranes on the cements. Overall, adding gelatin to the composition of CPC improved the handling characteristics such as setting time and mechanical properties, enhanced nanoapatite precipitation, and augmented the early cell proliferation rate and ALP activity. PMID:28176961

Peri-Implant Distribution of Polyethylene Debris in Postmortem-Retrieved Knee Arthroplasties: Can Polyethylene Debris Explain Loss of Cement-Bone Interlock in Successful Total Knee Arthroplasties?

PubMed

Cyndari, Karen I; Goodheart, Jacklyn R; Miller, Mark A; Oest, Megan E; Damron, Timothy A; Mann, Kenneth A

2017-07-01

Loss of mechanical interlock between cement and bone with in vivo service has been recently quantified for functioning, nonrevised, cemented total knee arthroplasties (TKAs). The cause of interlocking trabecular resorption is not known. The goal of this study is to quantify the distribution of PE debris at the cement-bone interface and determine if polyethylene (PE) debris is locally associated with loss of interlock. Fresh, nonrevised, postmortem-retrieved TKAs (n = 8) were obtained en bloc. Laboratory-prepared constructs (n = 2) served as negative controls. The intact cement-bone interface of each proximal tibia was embedded in Spurr's resin, sectioned, and imaged under polarized light to identify birefringent PE particles. PE wear particle number density was quantified at the cement-bone interface and distal to the interface, and then compared with local loss of cement-bone interlock. The average PE particle number density for postmortem-retrieved TKAs ranged from 8.6 (1.3) to 24.9 (3.1) particles/mm 2 (standard error) but was weakly correlated with years in service. The average particle number density was twice as high as distal (>5mm) to the interface compared to at the interface. The local loss of interlock at the interface was not related to the presence, absence, or particle density of PE. PE debris can migrate extensively along the cement-bone interface of well-fixed tibial components. However, the amount of local bone loss at the cement-bone interface was not correlated with the amount of PE debris at the interface, suggesting that the observed loss of trabecular interlock in these well-fixed TKAs may be due to alternative factors. Copyright © 2017 Elsevier Inc. All rights reserved.

Blooming gelatin: an individual additive for enhancing nanoapatite precipitation, physical properties, and osteoblastic responses of nanostructured macroporous calcium phosphate bone cements.

PubMed

Orshesh, Ziba; Hesaraki, Saeed; Khanlarkhani, Ali

2017-01-01

In recent years, there has been a great interest in using natural polymers in the composition of calcium phosphate bone cements to enhance their physical, mechanical, and biological performance. Gelatin is a partially hydrolyzed form of collagen, a natural component of bone matrix. In this study, the effect of blooming gelatin on the nanohydroxyapatite precipitation, physical and mechanical properties, and cellular responses of a calcium phosphate bone cement (CPC) was investigated. Various concentrations of blooming gelatin (2, 5, and 8 wt.%) were used as the cement liquid and an equimolar mixture of tetracalcium phosphate and dicalcium phosphate was used as solid phase. The CPC without any gelatin additive was also evaluated as a control group. The results showed that gelatin accelerated hydraulic reactions of the cement paste, in which the reactants were immediately converted into nanostructured apatite precipitates after hardening. Gelatin molecules induced 4%-10% macropores (10-300 μm) into the cement structure, decreased initial setting time by ~190%, and improved mechanical strength of the as-set cement. Variation in the above-mentioned properties was influenced by the gelatin concentration and progressed with increasing the gelatin content. The numbers of the G-292 osteoblastic cells on gelatin-containing CPCs were higher than the control group at entire culture times (1-14 days), meanwhile better alkaline phosphatase (ALP) activity was determined using blooming gelatin additive. The observation of cell morphologies on the cement surfaces revealed an appropriate cell attachment with extended cell membranes on the cements. Overall, adding gelatin to the composition of CPC improved the handling characteristics such as setting time and mechanical properties, enhanced nanoapatite precipitation, and augmented the early cell proliferation rate and ALP activity.

The development and nature of femoral head cam lesions following acetabular fractures.

PubMed

Berber, Onur; Foote, Julian; Sabharwal, Sanjeeve; Datta, Gorav; Bircher, Martin D

2014-01-01

The aim of acetabular fracture fixation is to restore joint congruity with restoration of the articular surface. Poor outcomes are seen where this has not been achieved. Letournel reported a collarette osteophyte seen postoperatively in a proportion of patients, which he suggested was an early precursor to the development of osteoarthritis. This is a retrospective study of patients treated at a tertiary referral unit who developed this lesion. The triangular index was measured in 48 of these patients and then correlated with their clinical findings, Oxford Hip Score and the presence of osteoarthritis. Length of follow-up, fracture classification, and joint congruency were also recorded. Results showed a statistically significant relationship between cam lesion size and the development of osteoarthritis (P = 0.008), cam lesion size and length of follow-up (P = 0.01), and between groin pain and postoperative joint congruency (LR = 0.035). These findings suggest that the appearance of a cam lesion is a poor long-term prognostic marker for the development of osteoarthritis in patients with an acetabular fracture.

The design, production and clinical application of 3D patient-specific implants with drilling guides for acetabular surgery.

PubMed

Merema, B J; Kraeima, J; Ten Duis, K; Wendt, K W; Warta, R; Vos, E; Schepers, R H; Witjes, M J H; IJpma, F F A

2017-11-01

An innovative procedure for the development of 3D patient-specific implants with drilling guides for acetabular fracture surgery is presented. By using CT data and 3D surgical planning software, a virtual model of the fractured pelvis was created. During this process the fracture was virtually reduced. Based on the reduced fracture model, patient-specific titanium plates including polyamide drilling guides were designed, 3D printed and milled for intra-operative use. One of the advantages of this procedure is that the personalised plates could be tailored to both the shape of the pelvis and the type of fracture. The optimal screw directions and sizes were predetermined in the 3D model. The virtual plan was translated towards the surgical procedure by using the surgical guides and patient-specific osteosynthesis. Besides the description of the newly developed multi-disciplinary workflow, a clinical case example is presented to demonstrate that this technique is feasible and promising for the operative treatment of complex acetabular fractures. Copyright © 2017 Elsevier Ltd. All rights reserved.

Examination of acetabular labral tear: a continued diagnostic challenge.

PubMed

Reiman, Michael P; Mather, Richard C; Hash, Thomas W; Cook, Chad E

2014-02-01

Acetabular labrum tears (ALT) are present in 22-55% of individuals with hip or groin pain. Tears can occur as a result of trauma or degeneration and are markedly associated with femoral acetabular morphological variations. An ALT can lead to biomechanical deficiencies and a loss of stability to the coxafemoral joint due to the labrum serving as a stabilising structure of this joint. The diagnosis of ALT is complex and multidimensional. Although tremendous improvements in diagnostic utility for ALT have occurred in the past 25 years, there are few patient history, clinical examination and special test findings that are unique to the condition. Imaging methods such as MRI, CT and ultrasonography have demonstrated reasonable accuracy, but not at a level that allows use as a stand-alone measure. Outcomes measures that focus on functional limitation or that are used to measure recovery should envelop the complexities of the condition and be captured using both self-report and physical performance measures. Only when patient history, objective testing, clinical examination special testing and imaging are combined can a clinician fully elucidate the multidimensional diagnosis of ALT.

Main components and human health risks assessment of PM10, PM2.5, and PM1 in two areas influenced by cement plants

NASA Astrophysics Data System (ADS)

Sánchez-Soberón, Francisco; Rovira, Joaquim; Mari, Montse; Sierra, Jordi; Nadal, Martí; Domingo, José L.; Schuhmacher, Marta

2015-11-01

Particulate matter (PM) is widely recorded as a source of diseases, being more harmful those particles with smaller size. PM is released to the environment as a consequence of different activities, being one of them cement production. The objective of this pilot study was to characterize PM of different sizes around cement facilities to have a preliminary approach of their origin, and evaluate their potential health risks. For that purpose, three fractions of PM (10, 2.5, and 1) were collected in the nearby area of two cement plants with different backgrounds (urban and rural) in different seasons. Subsequently, main components, outdoor and indoor concentrations, exposure, and human health risks were assessed. Greatest levels of PM1, organic matter, and metals were found in urban location, especially in winter. Consequently, environmental exposure and human health risks registered their highest values in the urban plant during wintertime. Exposure was higher for indoor activities, expressing some metals their peak values in the PM1 fraction. Non-carcinogenic risks were below the safety threshold (HQ < 1). Carcinogenic risks for most of the metals were below the limit of 10-5, except for Cr (VI), which exceeded it in both locations, but being in the range considered as assumable (10-6-10-4).

Have cementless and resurfacing components improved the medium-term results of hip replacement for patients under 60 years of age?

PubMed Central

Mason, James; Baker, Paul; Gregg, Paul J; Porter, Martyn; Deehan, David J; Reed, Mike R

2015-01-01

Background and purpose The optimal hip replacement for young patients remains unknown. We compared patient-reported outcome measures (PROMs), revision risk, and implant costs over a range of hip replacements. Methods We included hip replacements for osteoarthritis in patients under 60 years of age performed between 2003 and 2010 using the commonest brand of cemented, cementless, hybrid, or resurfacing prosthesis (11,622 women and 13,087 men). The reference implant comprised a cemented stem with a conventional polyethylene cemented cup and a standard-sized head (28- or 32-mm). Differences in implant survival were assessed using competing-risks models, adjusted for known prognostic influences. Analysis of covariance was used to assess improvement in PROMs (Oxford hip score (OHS) and EQ5D index) in 2014 linked procedures. Results In males, PROMs and implant survival were similar across all types of implants. In females, revision was statistically significantly higher in hard-bearing and/or small-stem cementless implants (hazard ratio (HR) = 4) and resurfacings (small head sizes (< 48 mm): HR = 6; large head sizes (≥ 48 mm): HR = 5) when compared to the reference cemented implant. In component combinations with equivalent survival, women reported significantly greater improvements in OHS with hybrid implants (22, p = 0.006) and cementless implants (21, p = 0.03) (reference, 18), but similar EQ5D index. For men and women, National Health Service (NHS) costs were lowest with the reference implant and highest with a hard-bearing cementless replacement. Interpretation In young women, hybrids offer a balance of good early functional improvement and low revision risk. Fully cementless and resurfacing components are more costly and do not provide any additional benefit for younger patients. PMID:25285617

Castable cements to prevent corrosion of metals in molten salts

DOE PAGES

Gomez-Vidal, Judith C.; Morton, E.

2016-04-22

Castable cements on metals form a protective barrier that is able to prevent permeation of molten salts towards metallic surfaces. Silica-based castable cements are capable of protecting containment metallic alloys from the corrosive attack of molten chlorides at temperatures as high as 650 °C. Boron nitride (BN) blocking the pores in the cured cement prevents permeation of the molten chloride towards the metal surface. The cements tested are not chemically stable in molten carbonates, because the bonding components dissolved into molten carbonates salt. The corrosion rate is 7.72±0.32 mm/year for bare stainless steel 347 in molten eutectic NaCl – 65.58more » wt% LiCl at 650 °C, which is the baseline used for determining how well the cement protects the metallic surfaces from corrosion. In particular the metal fully encapsulated with Aremco 645-N with pores filled with boron nitride immersed in molten eutectic NaCl – 65.58 wt% LiCl at 650 °C shows a corrosion rate of 9E-04 mm/year. Here, the present study gives initial corrosion rates. Long-term tests are required to determine if Aremco 645-N with BN coating on metal has long term chemical stability for blocking salt permeation through coating pores.« less

Systematic review of some prosthetic risk factors for periimplantitis.

PubMed

Pesce, Paolo; Canullo, Luigi; Grusovin, Maria Gabriella; de Bruyn, Hugo; Cosyn, Jan; Pera, Paolo

2015-09-01

The recent literature underlines a correlation between plaque and the development of periimplantitis but neglects the importance of the prosthetic factors. The purpose of this systematic review was to appraise the available literature to evaluate the role played by cement excess and misfitting components on the development of periimplantitis. An electronic search restricted to the English language was performed in PubMed, Embase, and the Cochrane Register up to September 1, 2014, based on a selected search algorithm. Only cohort studies and case-control studies were included without additional restrictions. The presence of periimplantitis and implant failure were considered primary and secondary outcome variables. The search produced 275 potentially relevant titles, of which only 2 were found eligible. They showed a correlation in cemented implant prostheses between cement excess and the presence of periimplant disease, especially in patients with a history of periodontal disease. After cement excess removal by means of debridement, disease symptoms disappeared around most of the implants. Scientific articles on prosthetic risk factors for periimplantitis are scarce. Although the studies found on cement remnants have a high risk for bias, cement excess seems to be associated with mucositis and possibly with periimplantitis, especially in patients with a history of periodontal disease. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Basic properties of calcium phosphate cement containing atelocollagen in its liquid or powder phases.

PubMed

Miyamoto, Y; Ishikawa, K; Takechi, M; Toh, T; Yuasa, T; Nagayama, M; Suzuki, K

1998-01-01

The basic properties of calcium phosphate cement (CPC) containing atelocollagen, the main component of the organic substrate in bone, were studied in an initial evaluation for the fabrication of modified CPC. The setting time of conventional CPC (c-CPC) was prolonged to over 100 min when c-CPC contained 1% or more atelocollagen. The diametral tensile strength (DTS) of c-CPC decreased linearly with the collagen content, descending to below the detection limit when the c-CPC contained 3% or more atelocollagen. Therefore, use of c-CPC as the base cement seems inappropriate for the fabrication of atelocollagen-containing CPC. In contrast, the cement set at 9-34 min when fast-setting CPC (FSCPC) was used as the base cement and contained 1-5% atelocollagen, respectively. Although addition of atelocollagen resulted in the decrease of DTS of the set mass, the DTS was approximately the same, 6-8 MPa, at contents of atelocollagen between 1% and 5%. When atelocollagen was added to FSCPC, the handling property was improved significantly. The paste also became more adhesive with increase in atelocollagen content. These properties are desirable for its use in surgical procedures since, for example, bony defects can be filled easily and without a space interposed between the bone and cement paste. Although there are some disadvantages for the addition of atelocollagen to CPC, it can be accepted as long as FSCPC was used as the base cement. We conclude that further evaluations of the effects of atelocollagen, such as biocompatibility, bone synthesis, and bone replacement behaviour should be done, using FSCPC as the base cement.

A biodetrital coral mound complex: Key to early diagenetic processes in the mississippian bangor limestone

USGS Publications Warehouse

Haywick, D.W.; Kopaska-Merkel, D. C.; Bersch, M.G.

2009-01-01

The Bangor Limestone is a Mississippian (Chesterian) shallow marine carbonate formation exposed over a large portion of the Interior Low Plateaus province of northern Alabama. It is dominated by oolitic grainstone and skeletal wackestone and packstone, but in one outcrop near Moulton, Alabama, the Bangor contains a five m thick, 25 m wide, oolitebiodetrital moundtidal flat succession. This sequence is interpreted as a 4th order sea level cycle. Four petrofacies (oolite, mound, skeletal and mudstone/dolomicrite) and four diagenetic phases (iron oxide, fibrous calcite cement, calcite spar cement and dolomite) are distinguished at the study site. Iron oxide, a minor component, stained and/or coated some ooids, intraclasts and skeletal components in the oolite petrofacies. Many of the allochems were stained prior to secondary cortical growth suggesting a short period of subaerial exposure during oolite sedimentation. The oolite petrofacies also contains minor amounts of fibrous calcite cement, a first generation marine cement, and rare infiltrated micrite that might represent a second phase of marine cement, or a first phase of meteoric cement (i.e., "vadose silt") (Dunham 1969). Intergranular pore space in all four petrofacies is filled with up to three phases of meteoric calcite spar cement. The most complete record of meteoric cementation is preserved within coralline void spaces in the mound petrofacies and indicates precipitation in the following order: (1) non-ferroan scalenohedral spar, (2) ferroan drusy spar (0.1-0.4 wt% Fe2+) and (3) non-ferroan drusy spar. The first scalenohedral phase of meteoric cement is distributed throughout the oolite and mound petrofacies. The ferroan phase of meteoric calcite is a void-filling cement that is abundant in the mound petrofacies and less common in the skeletal and mudstone/dolomicrite petrofacies. Non-ferroan drusy calcite is pervasive throughout the Bangor Limestone at the Moulton study site. Growth of the fourth diagenetic phase, dolomite, was the dominant event in the micrite/dolomicrite petrofacies, particularly just below an irregular surface overlain by a brecciated interval. The irregular surface is interpreted as an exposure surface. Three phases of dolomite occur below the exposure surface. The majority is finely crystalline, anhedral, and enriched in Si4+, criteria which support a supratidal or mixed hypersaline\\meteoric origin. Secondary phases of coarser euhedral non-ferroan and ferroan dolomite are restricted to fenestrae and other voids in the micrite/dolomicrite petrofacies and were precipitated during subsequent meteoric diagenesis. Diagenesis of the Bangor Limestone at the Moulton outcrop was dominated by synsedimentary and very early meteoric processes driven by periods of subaerial exposure. Large voids within the mound petrofacies were particularly important, as they remained open long enough to record a more detailed early meteoric cement stratigraphy that might not be evident in Bangor Limestone outcrops elsewhere in Alabama.

Influence of ferrite phase in alite-calcium sulfoaluminate cements

NASA Astrophysics Data System (ADS)

Duvallet, Tristana Yvonne Francoise

Since the energy crisis in 1970's, research on low energy cements with low CO2- emissions has been increasing. Numerous solutions have been investigated, and the goal of this original research is to create a viable hybrid cement with the components of both Ordinary Portland cement (OPC) and calcium sulfoaluminate cement (CSAC), by forming a material that contains both alite and calcium sulfoaluminate clinker phases. Furthermore, this research focuses on keeping the cost of this material reasonable by reducing aluminum requirements through its substitution with iron. The aim of this work would produce a cement that can use large amounts of red mud, which is a plentiful waste material, in place of bauxite known as an expensive raw material. Modified Bogue equations were established and tested to formulate this novel cement with different amounts of ferrite, from 5% to 45% by weight. This was followed by the production of cement from reagent chemicals, and from industrial by-products as feedstocks (fly ash, red mud and slag). Hydration processes, as well as the mechanical properties, of these clinker compositions were studied, along with the addition of gypsum and the impact of a ferric iron complexing additive triisopropanolamine (TIPA). To summarize this research, the influence of the addition of 5-45% by weight of ferrite phase, was examined with the goal of introducing as much red mud as possible in the process without negatively attenuate the cement properties. Based on this PhD dissertation, the production of high-iron alite-calcium sulfoaluminateferrite cements was proven possible from the two sources of raw materials. The hydration processes and the mechanical properties seemed negatively affected by the addition of ferrite, as this phase was not hydrated entirely, even after 6 months of curing. The usage of TIPA counteracted this decline in strength by improving the ferrite hydration and increasing the optimum amount of gypsum required in each composition. The mechanical data were equivalent to OPC strengths for some compositions with 25% ferrite. This preliminary work constitutes the first research phase of this novel cement and requires additional research for its improvement. Topics for additional research are identified in this dissertation. KEYWORDS: alite, calcium sulfoaluminate, ferrite, low-energy cement, triisopropanolamine.

Radiographic evaluation of BFX acetabular component position in dogs.

PubMed

Renwick, Alasdair; Gemmill, Toby; Pink, Jonathan; Brodbelt, David; McKee, Malcolm

2011-07-01

To assess the reliability of radiographic measurement of angle of lateral opening (ALO) and angle of version of BFX acetabular cups. In vitro radiographic study. BFX cups (24, 28, and 32 mm). Total hip replacement constructs (cups, 17 mm femoral head and a #7 CFX stem) were mounted on an inclinometer. Ventrodorsal radiographs were obtained with ALO varying between 21° and 70° and inclination set at 0°, 10°, 20°, and 30°. Radiographs were randomized using a random sequence generator. Three observers blinded to the radiograph order assessed ALO using 3 methods: (1) an ellipse method based on trigonometry; (2) using a measurement from the center of the femoral head to the truncated surface of the cup; (3) by visual estimation using a reference chart. Version was measured by assessing the ventral edge of the truncated surface. ALO methods 2 and 3 were accurate and precise to within 10° and were significantly more accurate and precise than method 1 (P < .001). All methods were significantly less accurate with increasing inclination. Version measurement was accurate and precise to within 7° with 0-20° of inclination, but significantly less accurate with 30° of inclination. Methods 2 and 3, but not method 1, were sufficiently accurate and precise to be clinically useful. Version measurement was clinically useful when inclination was ≤ 20°. © Copyright 2011 by The American College of Veterinary Surgeons.

Cementless total hip arthroplasty with ceramic-on-ceramic bearing in patients younger than 45 years with femoral-head osteonecrosis

PubMed Central

Choi, Yoowang; Kim, Jun-Shik

2009-01-01

Despite improvements in the quality of alumina ceramics, osteolysis has been reported anecdotally after total hip arthroplasty (THA) with use of a contemporary alumina-on-alumina ceramic bearing. The purpose of this study was to evaluate the clinical and radiographic outcomes of THA using alumina-on-alumina ceramic bearing and to determine osteolysis using radiographs and computed tomographic (CT) scans in young patients. Consecutive primary cementless THA using alumina-on-alumina ceramic bearing were performed in 64 patients (93 hips) who were younger than 45 years of age with femoral-head osteonecrosis. There were 55 men (84 hips) and nine women (nine hips). Average age was 38.2 (range 24–45) years. Average follow-up was 11.1 (range 10–13) years. Preoperative Harris Hip Score was 52.9 (range 22–58) points, which improved to 96 (range 85−100) points at the final follow-up examination. Two of 93 hips (2%) had clicking or squeaking sound. No hip had revision or aseptic loosening. Radiographs and CT scans demonstrated that no acetabular or femoral osteolysis was detected in any hip at the latest follow-up. Contemporary cementless acetabular and femoral components with alumina-on-alumina ceramic bearing couples function well with no osteolysis at a ten year minimum and average of 11.1-year follow-up in this series of young patients with femoral-head osteonecrosis. PMID:19784647

Inert Reassessment Document for 2-methyl-2,4-pentanediol - CAS No. 107-41-5

EPA Pesticide Factsheets

2-methyl-2,4-pentanediol is used as a chemical intermediate, a selective solvent in petroleum refining, a component of hydraulic fluids, an additive for cement, a component of industrial coatings, a solvent for inks, an additive for fuel and lubricants

Variation in functional pelvic tilt in patients undergoing total hip arthroplasty.

PubMed

Pierrepont, J; Hawdon, G; Miles, B P; Connor, B O'; Baré, J; Walter, L R; Marel, E; Solomon, M; McMahon, S; Shimmin, A J

2017-02-01

The pelvis rotates in the sagittal plane during daily activities. These rotations have a direct effect on the functional orientation of the acetabulum. The aim of this study was to quantify changes in pelvic tilt between different functional positions. Pre-operatively, pelvic tilt was measured in 1517 patients undergoing total hip arthroplasty (THA) in three functional positions - supine, standing and flexed seated (the moment when patients initiate rising from a seated position). Supine pelvic tilt was measured from CT scans, standing and flexed seated pelvic tilts were measured from standardised lateral radiographs. Anterior pelvic tilt was assigned a positive value. The mean pelvic tilt was 4.2° (-20.5° to 24.5°), -1.3° (-30.2° to 27.9°) and 0.6° (-42.0° to 41.3°) in the three positions, respectively. The mean sagittal pelvic rotation from supine to standing was -5.5° (-21.8° to 8.4°), from supine to flexed seated was -3.7° (-48.3° to 38.6°) and from standing to flexed seated was 1.8° (-51.8° to 39.5°). In 259 patients (17%), the extent of sagittal pelvic rotation could lead to functional malorientation of the acetabular component. Factoring in an intra-operative delivery error of ± 5° extends this risk to 51% of patients. Planning and measurement of the intended position of the acetabular component in the supine position may fail to predict clinically significant changes in its orientation during functional activities, as a consequence of individual pelvic kinematics. Optimal orientation is patient-specific and requires an evaluation of functional pelvic tilt pre-operatively. Cite this article: Bone Joint J 2017;99-B:184-91. ©2017 The British Editorial Society of Bone & Joint Surgery.

[Use of the Omega plate for stabilisation of acetabular fractures: first experience].

PubMed

Šrám, J; Taller, S; Lukáš, R; Endrych, L

2013-01-01

The aim of our study is to solve the problem of insufficient fixation of comminuted fractures of the quadrilateral plane and the iliopectineal line. These fixation problems occur while using the standard narrow 3.5 mm fixation plate applied from a modified Stoppa approach. A new plate developed by the authors--the Omega plate--fulfils the requirements. In the period 2010-2012, we performed 156 stabilisations of pelvic ring fractures and acetabular fractures. We used the modified Stoppa approach applying the standard fixation plate in 24 patients and the Omega plate in 15 patients. The patient group with the Omega plate included 10 male and five female patients with the average age of 61 years (range, 30-72). Only 11 patients were followed up, with an average period of 13.3 months, because one patient was lost to followup and three patients were shortly after surgery. The surgical technique of Omega plate application is described in detail. The clinical evaluation of post-operative results was based on the Harris Hip Score; the graphical results were rated using the Matta and Pohlemann criteria. The Stoppa approach alone was used in four patients, combination of two approaches (Stoppa and Kocher-Langenbeck approach) was used in six cases and three approaches were employed in five patients. No adverse intra- or post-operative events were recorded. Excellent or satisfactory graphical results were obtained in 12 patients and an unsatisfactory graphical outcome was recorded in three cases. In the follow-up period ranging from 8 to 22 months, 11 patients healed. Late complications included avascular femoral head necrosis in two and severe post-traumatic coxarthrosis in three patients. Due to these complications, all five patients underwent total hip arthroplasty without previous Omega plate removal at an average interval of 15 months from the primary pelvic surgery. They were not included in the follow-up evaluation. The remaining six patients had an average Harris Hip Score of 88 points (range, 81-98). The novel plate, shaped as a reverse omega letter, enables fixation of the quadrilateral area of the acetabulum through pressure of the arc of the plate against this area. Hitches, with holes for screw insertion, attached to the Omega plate in its middle part allow for fixation of fragments above the linea arcuata simply by pressure. Hitches in the ventral part provide for plate fixation to the ventral acetabular column and the superior pubic ramus. Hitches in the posterior segment of the plate facilitate insertion of a long screw in the posterior acetabular column from an additional iliac approach for stabilisation of simple acetabular fractures. The Omega plates are manufactured in several modifications. The Omega plate enables us to fix fractures of the superior pubic ramus, fractures of the anterior acetabular column, fractures of the quadrilateral acetabular plate, fractures in the iliopectineal line and simple fractures of the posterior column. A CT-defined projection of the pelvic inlet based on pre-operative CT scans allows us to choose the appropriate plate size and to shape the plate pre-operatively. After a technically well performed Stoppa approach and good fragment reduction, the application of an Omega plate is easy if our recommendations are followed. Fixation of all fragments of the anterior column and the quadrilateral plate is very stable and the Omega plate is highly resistant to secondary loss of reduction. A potential total hip arthroplasty does not require Omega plate removal.

Early-age hydration and volume change of calcium sulfoaluminate cement-based binders

NASA Astrophysics Data System (ADS)

Chaunsali, Piyush

Shrinkage cracking is a predominant deterioration mechanism in structures with high surface-to-volume ratio. One way to allay shrinkage-induced stresses is to use calcium sulfoaluminate (CSA) cement whose early-age expansion in restrained condition induces compressive stress that can be utilized to counter the tensile stresses due to shrinkage. In addition to enhancing the resistance against shrinkage cracking, CSA cement also has lower carbon footprint than that of Portland cement. This dissertation aims at improving the understanding of early-age volume change of CSA cement-based binders. For the first time, interaction between mineral admixtures (Class F fly ash, Class C fly ash, and silica fume) and OPC-CSA binder was studied. Various physico-chemical factors such as the hydration of ye'elimite (main component in CSA cement), amount of ettringite (the main phase responsible for expansion in CSA cement), supersaturation with respect to ettringite in cement pore solution, total pore volume, and material stiffness were monitored to examine early-age expansion characteristics. This research validated the crystallization stress theory by showing the presence of higher supersaturation level of ettringite, and therefore, higher crystallization stress in CSA cement-based binders. Supersaturation with respect to ettringite was found to increase with CSA dosage and external supply of gypsum. Mineral admixtures (MA) altered the expansion characteristics in OPC-CSA-MA binders with fixed CSA cement. This study reports that fly ash (FA) behaves differently depending on its phase composition. The Class C FA-based binder (OPC-CSA-CFA) ceased expanding beyond two days unlike other OPC-CSA-MA binders. Three factors were found to govern expansion of CSA cement-based binders: 1) volume fraction of ettringite in given pore volume, 2) saturation level of ettringite, and 3) dynamic modulus. Various models were utilized to estimate the macroscopic tensile stress in CSA cement-based binders without taking into account the viscoelastic effects. For the first time, model based on poromechanics was used to calculate the macroscopic tensile stress that develops in CSA cement-based binders due to crystallization of ettringite. The models enabled a reasonable prediction of tensile stress due to crystallization of ettringite including the failure of an OPC-CSA binder which had high CSA cement content. Elastic strain based on crystallization stress was calculated and compared with the observed strain. A mismatch between observed and calculated elastic strain indicated the presence of early-age creep. Lastly, the application of CSA cement in concretes is discussed to link the paste and concrete behavior.

Restoration of the centre of rotation in primary total hip arthroplasty: the influence of acetabular floor depth and reaming technique.

PubMed

Meermans, G; Doorn, J Van; Kats, J-J

2016-12-01

One goal of total hip arthroplasty is to restore normal hip anatomy. The aim of this study was to compare displacement of the centre of rotation (COR) using a standard reaming technique with a technique in which the acetabulum was reamed immediately peripherally and referenced off the rim. In the first cohort the acetabulum was reamed to the floor followed by sequentially larger reamers. In the second cohort the acetabulum was only reamed peripherally, starting with a reamer the same size as the native femoral head. Anteroposterior pelvic radiographs were analysed for acetabular floor depth and vertical and horizontal position of the COR. Horizontally, the mean medial displacement of the COR was 0.8 mm (standard deviation (sd) 1.4) in the peripheral remaing group and 5.0 mm (sd 3.30) in the standard reaming group (p < 0.001). Vertically, the mean superior displacement of the COR was 0.7 mm (sd 1.3) in the peripheral reaming group and 3.7 mm (sd 2.6) in the standard reaming group (p < 0.001). In the standard reaming group, there was a strong correlation between the pre-operative acetabular floor depth and displacement of the COR (p < 0.001). Reaming the acetabulum to the floor can lead to significant displacement of the COR medially and superiorly. This displacement is related to the pre-operative acetabular floor depth and cannot always be compensated by using a high offset stem. Cite this article: Bone Joint J 2016;98-B:1597-603. ©2016 The British Editorial Society of Bone & Joint Surgery.

Pelvic reconstructions following peri-acetabular bone tumour resections using a cementless ice-cream cone prosthesis with dual mobility cup.

PubMed

Issa, Samir-Pierre; Biau, David; Babinet, Antoine; Dumaine, Valérie; Le Hanneur, Malo; Anract, Philippe

2018-01-27

Despite numerous reconstructive techniques and prosthetic devices, pelvic reconstructions following peri-acetabular malignant tumours resections are highly challenging. In the present study, we describe our experience with the Integra® (Lépine, Genay, France) ice-cream cone prosthesis in such indications. The objective was to assess the mid-term outcomes of this device. Twenty-four patients' chart with peri-acetabular malignant tumours, who underwent types II or II + III peri-acetabular resections according to Enneking and Dunham with subsequent reconstruction using the Integra® prosthesis between February 2009 and February 2015, were reviewed. Seventeen cases were primary surgeries and seven cases were revisions (i.e., failures of previous reconstructions for pelvic tumours). All living patients with the prosthesis implanted were functionally assessed, using the musculoskeletal tumour society (MSTS) and Postel-Merle d'Aubigné (PMA) scores. After a mean follow-up of 49 ± 26 months (range, 8 to 94 months), 21 patients were alive (88%), including 15 patients continuously disease-free (63%). MSTS and PMA scores averaged 72 ± 13% (range, 43 to 87%) and 14.6 ± 2.6 (range, 9 to 18), respectively. Fourteen patients (58%) presented at least one complication during follow-up, including four cases of deep infection (17%), four cases of dislocation (17%), and two mechanical failures (8%). At 5 years, the implant survival rate was 75%. In comparison to previous reconstructive techniques that we used in similar indications, functional and oncologic outcomes were improved with the Integra® implant. However, as commonly observed in pelvic bone tumour surgery, complication rates remain significant. Therapeutic, Level IV-Retrospective Cases Series.

Cup press fit in uncemented THA depends on sex, acetabular shape, and surgical technique.

PubMed

García-Rey, Eduardo; García-Cimbrelo, Eduardo; Cruz-Pardos, Ana

2012-11-01

Uncemented press-fit cups provide bone fixation in primary THA, but the use of screws is sometimes necessary to achieve primary stability of the socket. However, it is unclear whether and when screws should be used. We analyzed the factors related to screw use with a press-fit uncemented cup and assessed whether screw use is associated with the same rates of loosening and revision as a press-fit technique. We retrospectively reviewed 248 patients who underwent THA using the same prosthetic design. Eighty-eight hips had screws to achieve primary cup fixation (Group 1), and 189 did not (Group 2). Mean age was 50 years (range, 14-73 years). We analyzed factors related to the patient, acetabular type, and reconstruction of the rotation center of the hip. Minimum followup was 5 years (mean, 8.9 years; range, 5-12 years). We found higher screw use in women, patients with less physical activity, Acetabular Types A or C, and a distance from the center of the prosthetic femoral head to the normal center of rotation of more than 3 mm. There were four revisions in Group 1 and five in Group 2. Eight hips had radiographic loosening in Group 1 and nine in Group 2. Cups with a postoperative abduction angle of more than 50° had a higher risk for loosening. Press fit was achieved less frequently in women and patients with Acetabular Types A or C and less physical activity; a closer distance to the normal center of rotation decreased screw use. Screw use to augment fixation achieved survival similar to that of a press-fit cup. Level II, prognostic study. See Instructions for Authors for a complete description of levels of evidence.

The influence of head diameter and wall thickness on deformations of metallic acetabular press-fit cups and UHMWPE liners: a finite element analysis.

PubMed

Goebel, Paul; Kluess, Daniel; Wieding, Jan; Souffrant, Robert; Heyer, Horst; Sander, Manuela; Bader, Rainer

2013-03-01

To increase the range of motion of total hip endoprostheses, prosthetic heads need to be enlarged, which implies that the cup and/or liner thickness must decrease. This may have negative effects on the wear rate, because the acetabular cups and liners could deform during press-fit implantation and hip joint loading. We compared the metal cup and polyethylene liner deformations that occurred when different wall thicknesses were used in order to evaluate the resulting changes in the clearance of the articulating region. A parametric finite element model utilized three cup and liner wall thicknesses to analyze cup and liner deformations after press-fit implantation into the pelvic bone. The resultant hip joint force during heel strike was applied while the femur was fixed, accounting for physiological muscle forces. The deformation behavior of the liner under joint loading was therefore assessed as a function of the head diameter and the resulting clearance. Press-fit implantation showed diametral cup deformations of 0.096, 0.034, and 0.014 mm for cup wall thicknesses of 3, 5, and 7 mm, respectively. The largest deformations (average 0.084 ± 0.003 mm) of liners with thicknesses of 4, 6, and 8 mm occurred with the smallest cup wall thickness (3 mm). The smallest liner deformation (0.011 mm) was obtained with largest cup and liner wall thicknesses. Under joint loading, liner deformations in thin-walled acetabular cups (3 mm) reduced the initial clearance by about 50 %. Acetabular press-fit cups with wall thicknesses of ≤5 mm should only be used in combination with polyethylene liners >6 mm thick in order to minimize the reduction in clearance.

Initial stability of cementless acetabular cups: press-fit and screw fixation interaction--an in vitro biomechanical study.

PubMed

Tabata, Tomonori; Kaku, Nobuhiro; Hara, Katsutoshi; Tsumura, Hiroshi

2015-04-01

Press-fit and screw fixation are important technical factors to achieve initial stability of a cementless acetabular cup for good clinical results of total hip arthroplasty. However, how these factors affect one another in initial cup fixation remains unclear. Therefore, this study aimed to evaluate the mutual influence between press-fit and screw fixation on initial cup stability. Foam bone was subjected to exact hemispherical-shape machining to diameters of 48, 48.5 and 49 mm. A compressive force was applied to ensure seating of a 48-mm-diameter acetabular cup in the foam bone prior to testing. Screws were inserted in six different conditions and tightened in a radial direction at the same torque strength. Then, the socket was rotated with a twist-testing machine, and the torque value at the start of axial rotation between the socket and the foam bone was measured under each screw condition. The torque values for the 48-mm-diameter reaming were >20 N m higher than those for the 48.5- and 49-mm-diameter reaming in each screw condition, indicating that press-fit fixation is stronger than screw fixation. Meanwhile, torque values for the 48.5- and 49-mm-diameter reaming tended to increase with increasing the number of screws. According to our experiment, press-fit fixation of a cementless acetabular cup achieved rigid stability. Although the supplemental screws increased stability of the implant under good press-fit conditions, they showed little impact on whole-cup stability. In the case of insufficient press-fit fixation, cup stability depends on screw stability and increasing the number of additional screws increases cup stability.

Sarcopenia Is Predictive of 1-Year Mortality After Acetabular Fractures in Elderly Patients.

PubMed

Mitchell, Phillip M; Collinge, Cory A; OʼNeill, David E; Bible, Jesse E; Mir, Hassan R

2018-06-01

To determine whether sarcopenia is an independent predictor of mortality in geriatric acetabular fractures. Retrospective cohort. American College of Surgeons Level I trauma center. One hundred and forty-six patients over the age 60 with acetabular fractures treated at our institution over a 12-year period. The primary outcome was 1-year mortality, collected using the Social Security Death Index. We used the psoas:lumbar vertebral index (PLVI), calculated using the cross-sectional area of the L4 vertebral body and the left and right psoas muscles, to assess for sarcopenia. Using a multivariate logistic regression model, we found that low PLVI was associated with increased 1-year mortality (P = 0.046) when controlling for age, gender, Charlson Comorbidity Index, Injury Severity Score (ISS), smoking status, and associated pelvic ring injury. Increasing age and ISS also showed a relationship with 1-year mortality in this cohort (P < 0.001, P < 0.001, respectively). We defined sarcopenia as those patients in the lowest quartile of PLVI. The mortality rate of this cohort was 32.4%, compared with 11.0% in patients without sarcopenia (odds ratio 4.04; 95% confidence interval 1.62-10.1). Age >75 years, ISS >14, and sarcopenia had 1-year mortality rates of 37.1%, 30.9%, and 32.4%, respectively. In patients with all 3 factors, the mortality rate was 90%. Sarcopenia is an independent risk factor for 1-year mortality in elderly patients with acetabular fractures. This study highlights the importance of objective measures to assess frailty in elderly patients who have sustained fractures about the hip and pelvis. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Myofascial treatment for patients with acetabular labral tears: a single-subject research design study.

PubMed

Cashman, Glenn E; Mortenson, W Ben; Gilbart, Michael K

2014-08-01

Single-subject research design using 4 consecutive patients. To assess whether treatment using soft tissue therapy (ART or Active Release Technique), stretching, and strengthening of the hip abductors, hip external rotators, and tensor fascia latae muscles reduces pain and improves self-reported hip function in patients with acetabular labral tears who also have posterolateral hip pain of suspected myofascial origin. Acetabular labral tears cause pain in some but not all patients. Pain commonly presents anteriorly but may also present posteriorly and laterally. The standard of care is arthroscopic repair, which helps many but not all patients. It is possible that these patients may present with extra-articular contributions to their pain, such as myofascial pain, making their clinical presentation more complex. No previous study has assessed soft tissue therapy as a treatment option for this subset of patients. This A-B-A design used repeated measures of the Hip Outcome Score and visual analog scale for pain. Four patients were treated for 6 to 8 weeks, using a combination of soft tissue therapy, stretching, and strengthening for the hip abductors, external rotators, and tensor fascia latae. Data were assessed visually, statistically, and by comparing mean differences before and after intervention. All 4 patients experienced both statistically significant and clinically meaningful improvement in posterolateral hip pain and hip-related function. Three patients also experienced reduction in anteromedial hip pain. Myofascial hip pain may contribute to hip-related symptoms and disability in patients with acetabular labral tears and posterolateral hip pain. These patients may benefit from soft tissue therapy combined with stretching and strengthening exercises targeting the hip abductors, tensor fascia latae, and hip external rotator muscles. Level of Evidence Therapy, level 4.

Obstacles to reduction in infantile developmental dysplasia of the hip

PubMed Central

Studer, K.; Williams, N.; Studer, P.; Baker, M.; Glynn, A.; Foster, B. K.; Cundy, P. J.

2017-01-01

Abstract Purpose Identification of anatomical structures that block ­reduction in developmental dysplasia of the hip (DDH) is ­important for the management of this challenging condition. Obstacles to reduction seen on arthrogram are well-known. However, despite the increasing use of MRI in the assessment of adequacy of reduction in DDH, the interpretation of MRI patho-anatomy is ill-defined with a lack of relevant literature to guide clinicians. Method This is a retrospective analysis of the MRI of patients with DDH treated by closed reduction over a five-year period (between 2009 and 2014). Neuromuscular and genetic disorders were excluded. Each MRI was analysed by two orthopaedic surgeons and a paediatric musculoskeletal radiologist to identify the ligamentum teres, pulvinar, transverse acetabular ligament (TAL), capsule, labrum and acetabular roof cartilage hypertrophy. Inter- and intraobserver reliability was calculated. The minimum follow-up was 12 months. Results A total of 29 patients (38 hips) underwent closed reduction for treatment of DDH. Eight hips showed persistent subluxation on post-operative MRI. Only three of these eight hips showed an abnormality on arthrogram. The pulvinar was frequently interpreted as ‘abnormal’ on MRI. The main obstacles identified on MRI were the ligamentum teres (15.8%), labrum (13.1%) and acetabular roof cartilage hypertrophy (13.2%). The inter-rater reliability was good for TAL, capsule and pulvinar; moderate for ligamentum teres and labrum; and poor for hypertrophied cartilage. Conclusion The labrum, ligamentum teres and acetabular roof cartilage hypertrophy are the most important structures seen on MRI preventing complete reduction of DDH. Focused interpretation of these structures may assist in the management of DDH. PMID:29081850

Biomechanical analysis using FEA and experiments of a standard plate method versus three cable methods for fixing acetabular fractures with simultaneous THA.

PubMed

Aziz, Mina S R; Dessouki, Omar; Samiezadeh, Saeid; Bougherara, Habiba; Schemitsch, Emil H; Zdero, Radovan

2017-08-01

Acetabular fractures potentially account for up to half of all pelvic fractures, while pelvic fractures potentially account for over one-tenth of all human bone fractures. This is the first biomechanical study to assess acetabular fracture fixation using plates versus cables in the presence of a total hip arthroplasty, as done for the elderly. In Phase 1, finite element (FE) models compared a standard plate method versus 3 cable methods for repairing an acetabular fracture (type: anterior column plus posterior hemi-transverse) subjected to a physiological-type compressive load of 2207N representing 3 x body weight for a 75kg person during walking. FE stress maps were compared to choose the most mechanically stable cable method, i.e. lowest peak bone stress. In Phase 2, mechanical tests were then done in artificial hemipelvises to compare the standard plate method versus the optimal cable method selected from Phase 1. FE analysis results showed peak bone stresses of 255MPa (Plate method), 205MPa (Mears cable method), 250MPa (Kang cable method), and 181MPa (Mouhsine cable method). Mechanical tests then showed that the Plate method versus the Mouhsine cable method selected from Phase 1 had higher stiffness (662versus 385N/mm, p=0.001), strength (3210versus 2060N, p=0.009), and failure energy (8.8versus 6.2J, p=0.002), whilst they were statistically equivalent for interfragmentary sliding (p≥0.179) and interfragmentary gapping (p≥0.08). The Plate method had superior mechanical properties, but the Mouhsine cable method may be a reasonable alternative if osteoporosis prevents good screw thread interdigitation during plating. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Computed tomography arthrography with traction in the human hip for three-dimensional reconstruction of cartilage and the acetabular labrum

PubMed Central

Henak, C.R.; Abraham, C.L.; Peters, C.L.; Sanders, R.K.; Weiss, J.A.; Anderson, A.E.

2014-01-01

AIM To develop and demonstrate the efficacy of a computed tomography arthrography (CTA) protocol for the hip that enables accurate three-dimensional reconstructions of cartilage and excellent visualization of the acetabular labrum. MATERIALS AND METHODS Ninety-three subjects were imaged (104 scans); 68 subjects with abnormal anatomy, 11 patients after periacetabular osteotomy surgery, and 25 subjects with normal anatomy. Fifteen to 25 ml of contrast agent diluted with lidocaine was injected using a lateral oblique approach. A Hare traction splint applied traction during CT. The association between traction force and intra-articular joint space was assessed qualitatively under fluoroscopy. Cartilage geometry was reconstructed from the CTA images for 30 subjects; the maximum joint space under traction was measured. RESULTS Using the Hare traction splint, the intra-articular space and boundaries of cartilage could be clearly delineated throughout the joint; the acetabular labrum was also visible. Dysplastic hips required less traction (~5 kg) than normal and retroverted hips required (>10 kg) to separate the cartilage. An increase in traction force produced a corresponding widening of the intra-articular joint space. Under traction, the maximum width of the intra-articular joint space during CT ranged from 0.98–6.7 mm (2.46 ± 1.16 mm). CONCLUSIONS When applied to subjects with normal and abnormal hip anatomy, the CTA protocol presented yields clear delineation of the cartilage and the acetabular labrum. Use of a Hare traction splint provides a simple, cost-effective method to widen the intra-articular joint space during CT, and provides flexibility to vary the traction as required. PMID:25070373

The obturator oblique and iliac oblique/outlet views predict most accurately the adequate position of an anterior column acetabular screw.

PubMed

Guimarães, João Antonio Matheus; Martin, Murphy P; da Silva, Flávio Ribeiro; Duarte, Maria Eugenia Leite; Cavalcanti, Amanda Dos Santos; Machado, Jamila Alessandra Perini; Mauffrey, Cyril; Rojas, David

2018-06-08

Percutaneous fixation of the acetabulum is a treatment option for select acetabular fractures. Intra-operative fluoroscopy is required, and despite various described imaging strategies, it is debatable as to which combination of fluoroscopic views provides the most accurate and reliable assessment of screw position. Using five synthetic pelvic models, an experimental setup was created in which the anterior acetabular columns were instrumented with screws in five distinct trajectories. Five fluoroscopic images were obtained of each model (Pelvic Inlet, Obturator Oblique, Iliac Oblique, Obturator Oblique/Outlet, and Iliac Oblique/Outlet). The images were presented to 32 pelvic and acetabular orthopaedic surgeons, who were asked to draw two conclusions regarding screw position: (1) whether the screw was intra-articular and (2) whether the screw was intraosseous in its distal course through the bony corridor. In the assessment of screw position relative to the hip joint, accuracy of surgeon's response ranged from 52% (iliac oblique/outlet) to 88% (obturator oblique), with surgeon confidence in the interpretation ranging from 60% (pelvic inlet) to 93% (obturator oblique) (P < 0.0001). In the assessment of intraosseous position of the screw, accuracy of surgeon's response ranged from 40% (obturator oblique/outlet) to 79% (iliac oblique/outlet), with surgeon confidence in the interpretation ranging from 66% (iliac oblique) to 88% (pelvic inlet) (P < 0.0001). The obturator oblique and obturator oblique/outlet views afforded the most accurate and reliable assessment of penetration into the hip joint, and intraosseous position of the screw was most accurately assessed with pelvic inlet and iliac oblique/outlet views. Clinical Question.

Influence of soft tissue in the assessment of the primary fixation of acetabular cup implants using impact analyses.

PubMed

Bosc, Romain; Tijou, Antoine; Rosi, Giuseppe; Nguyen, Vu-Hieu; Meningaud, Jean-Paul; Hernigou, Philippe; Flouzat-Lachaniette, Charles-Henri; Haiat, Guillaume

2018-06-01

The acetabular cup (AC) implant primary stability is an important determinant for the success of cementless hip surgery but it remains difficult to assess the AC implant fixation in the clinic. A method based on the analysis of the impact produced by an instrumented hammer on the ancillary has been developed by our group (Michel et al., 2016a). However, the soft tissue thickness present around the acetabulum may affect the impact response, which may hamper the robustness of the method. The aim of this study is to evaluate the influence of the soft tissue thickness (STT) on the acetabular cup implant primary fixation evaluation using impact analyses. To do so, different AC implants were inserted in five bovine bone samples. For each sample, different stability conditions were obtained by changing the cavity diameter. For each configuration, the AC implant was impacted 25 times with 10 and 30 mm of soft tissues positioned underneath the sample. The averaged indicator I m was determined based on the amplitude of the signal for each configuration and each STT and the pull-out force was measured. The results show that the resonance frequency of the system increases when the value of the soft tissue thickness decreases. Moreover, an ANOVA analysis shows that there was no significant effect of the value of soft tissue thickness on the values of the indicator I m (F = 2.33; p-value = 0.13). This study shows that soft tissue thickness does not appear to alter the prediction of the acetabular cup implant primary fixation obtained using the impact analysis approach, opening the path towards future clinical trials. Copyright © 2018 Elsevier Ltd. All rights reserved.

Modeling of a self-healing process in blast furnace slag cement exposed to accelerated carbonation

NASA Astrophysics Data System (ADS)

Zemskov, Serguey V.; Ahmad, Bilal; Copuroglu, Oguzhan; Vermolen, Fred J.

2013-02-01

In the current research, a mathematical model for the post-damage improvement of the carbonated blast furnace slag cement (BFSC) exposed to accelerated carbonation is constructed. The study is embedded within the framework of investigating the effect of using lightweight expanded clay aggregate, which is incorporated into the impregnation of the sodium mono-fluorophosphate (Na-MFP) solution. The model of the self-healing process is built under the assumption that the position of the carbonation front changes in time where the rate of diffusion of Na-MFP into the carbonated cement matrix and the reaction rates of the free phosphate and fluorophosphate with the components of the cement are comparable to the speed of the carbonation front under accelerated carbonation conditions. The model is based on an initial-boundary value problem for a system of partial differential equations which is solved using a Galerkin finite element method. The results obtained are discussed and generalized to a three-dimensional case.

Development of an alternate pathway for materials destined for disposition to WIPP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ayers, Georgette Y; Mckerley, Bill; Veazey, Gerald W

2010-01-01

The Los Alamos National Laboratory currently has an inventory of process residues that may be viable candidates for disposition to the Waste Isolation Pilot Project (WIPP) located at Carlsbad, New Mexico. A recent 'Attractiveness Level D' exemption allows for the discard of specified intractable materials regardless of the percent plutonium. However, the limits with respect to drum loadings must be met. Cementation is a key component of the aqueous nitrate flowsheet and serves as a 'bleed-off' stream for impurities separated from the plutonium during processing operations. The main 'feed' to the cementation operations are the 'bottoms' from the evaporation process.more » In the majority of cases, the cemented bottoms contain less than the allowed amount per drum for WIPP acceptance. This project would expand the route to WIPP for items that have no defined disposition path, are difficult to process, have been through multiple passes, have no current recovery operations available to recover the plutonium and that are amenable to cementation. This initial work will provide the foundation for a full scale disposition pathway of the candidate materials. Once the pathway has been expanded and a cementation matrix developed, routine discard activities will be initiated.« less

The role of fixation and bone quality on the mechanical stability of tibial knee components.

PubMed

Lee, R W; Volz, R G; Sheridan, D C

1991-12-01

Tibial component loosening remains one of the major causes of failure of cemented and noncemented total knee arthroplasties. In this study, the authors identified the role of implant design, method of fixation, and bone density as it related to implant stability. The physical properties of "good" and "bad" bone were simulated using a "good" and "bad" foam model of the proximal tibia, fabricated in the laboratory from DARO RF-100 foam. A generic tibial component permitting various fixation designs was implanted into "good" and "bad" variable density foam tibial models in both cemented and noncemented modes. The mechanical stability of the implants was determined using a Materials Testing Machine by the application of an eccentrically applied cyclic load. The micromotion (subsidence and lift-off) of the tibial implants was recorded using two Linear Variable Differential Transformers. Statistically significant differences in implant stability were recorded as a function of fixation method. The most rigid implant fixation was achieved using four peripherally placed, 6.5-mm cancellous screws. The addition of a central stem added stability only in the case of "poor" quality foam. The mechanical stability of noncemented implants related directly to the density of the foam. Implant stability was greatly enhanced in "poor" quality foam by the use of cement. The method of implant fixation and bone density are critical determinants to tibial implant stability.