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.

[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.

[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.

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.

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.

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.

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.

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

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).

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.

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.

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 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.

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.

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

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.

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.

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.

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.

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.

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.

Initial stability of a highly porous titanium cup in an acetabular bone defect model.

PubMed

Yoshimoto, Kensei; Nakashima, Yasuharu; Wakiyama, Miyo; Hara, Daisuke; Nakamura, Akihiro; Iwamoto, Mikio

2018-04-12

The purpose of this study was to quantify the initial stability of a highly porous titanium cup using an acetabular bone defect model. The maximum torque of a highly porous titanium cup, with a pore size of 640 μm and porosity of 60%, was measured using rotational and lever-out torque testing and compared to that of a titanium-sprayed cup. The bone models were prepared using a polyurethane foam block and had three levels of bone coverage: 100, 70, and 50%. The highly porous titanium cup demonstrated significantly higher maximum torque than the titanium-sprayed cups in the three levels of bone defects. On rotational torque testing, it was found to be 1.5, 1.3, and 1.3 times stronger than the titanium-sprayed cups with 100, 70 and 50% bone coverage, respectively. Furthermore, it was found to be 2.2, 2.3, and 1.5 times stronger on lever-out testing than the titanium-sprayed cup. No breakage in the porous layers was noted during the testing. This study provides additional evidence of the initial stability of highly porous titanium cup, even in the presence of acetabular bone defects. Copyright © 2018. Published by Elsevier B.V.

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.

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.

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.

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.

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.

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.

Acetabular cup position and risk of dislocation in primary total hip arthroplasty.

PubMed

Seagrave, Kurt G; Troelsen, Anders; Malchau, Henrik; Husted, Henrik; Gromov, Kirill

2017-02-01

Background and purpose - Hip dislocation is one of the most common complications following total hip arthroplasty (THA). Several factors that affect dislocation have been identified, including acetabular cup positioning. Optimal values for cup inclination and anteversion are debatable. We performed a systematic review to describe the different methods for measuring cup placement, target zones for cup positioning, and the association between cup positioning and dislocation following primary THA. Methods - A systematic search of literature in the PubMed database was performed (January and February 2016) to identify articles that compared acetabular cup positioning and the risk of dislocation. Surgical approach and methods for measurement of cup angles were also considered. Results - 28 articles were determined to be relevant to our research question. Some articles demonstrated that cup positioning influenced postoperative dislocation whereas others did not. The majority of articles could not identify a statistically significant difference between dislocating and non-dislocating THA with regard to mean angles of cup anteversion and inclination. Most of the articles that assessed cup placement within the Lewinnek safe zone did not show a statistically significant reduction in dislocation rate. Alternative target ranges have been proposed by several authors. Interpretation - The Lewinnek safe zone could not be justified. It is difficult to draw broad conclusions regarding a definitive target zone for cup positioning in THA, due to variability between studies and the likely multifactorial nature of THA dislocation. Future studies comparing cup positioning and dislocation rate should investigate surgical approach separately. Standardized tools for measurement of cup positioning should be implemented to allow comparison between studies.

Acetabular cup position and risk of dislocation in primary total hip arthroplasty

PubMed Central

Seagrave, Kurt G; Troelsen, Anders; Malchau, Henrik; Husted, Henrik; Gromov, Kirill

2017-01-01

Background and purpose — Hip dislocation is one of the most common complications following total hip arthroplasty (THA). Several factors that affect dislocation have been identified, including acetabular cup positioning. Optimal values for cup inclination and anteversion are debatable. We performed a systematic review to describe the different methods for measuring cup placement, target zones for cup positioning, and the association between cup positioning and dislocation following primary THA. Methods — A systematic search of literature in the PubMed database was performed (January and February 2016) to identify articles that compared acetabular cup positioning and the risk of dislocation. Surgical approach and methods for measurement of cup angles were also considered. Results— 28 articles were determined to be relevant to our research question. Some articles demonstrated that cup positioning influenced postoperative dislocation whereas others did not. The majority of articles could not identify a statistically significant difference between dislocating and non-dislocating THA with regard to mean angles of cup anteversion and inclination. Most of the articles that assessed cup placement within the Lewinnek safe zone did not show a statistically significant reduction in dislocation rate. Alternative target ranges have been proposed by several authors. Interpretation— The Lewinnek safe zone could not be justified. It is difficult to draw broad conclusions regarding a definitive target zone for cup positioning in THA, due to variability between studies and the likely multifactorial nature of THA dislocation. Future studies comparing cup positioning and dislocation rate should investigate surgical approach separately. Standardized tools for measurement of cup positioning should be implemented to allow comparison between studies. PMID:27879150

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.

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

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.

A new technique for radiographic measurement of acetabular cup orientation.

PubMed

Derbyshire, Brian; Diggle, Peter J; Ingham, Christopher J; Macnair, Rory; Wimhurst, James; Jones, Henry Wynn

2014-02-01

Accurate radiographic measurement of acetabular cup orientation is required in order to assess susceptibility to impingement, dislocation, and edge loading wear. In this study, the accuracy and precision of a new radiographic cup orientation measurement system were assessed and compared to those of two commercially available systems. Two types of resurfacing hip prostheses and an uncemented prosthesis were assessed. Radiographic images of each prosthesis were created with the cup set at different, known angles of version and inclination in a measurement jig. The new system was the most accurate and precise and could repeatedly measure version and inclination to within a fraction of a degree. In addition it has a facility to distinguish cup retroversion from anteversion on anteroposterior radiographs. © 2013.

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

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.

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.

High proximal migration in cemented acetabular revisions operated with bone impaction grafting; 47 revision cups followed with RSA for 17 years.

PubMed

Mohaddes, Maziar; Herberts, Peter; Malchau, Henrik; Johanson, Per-Erik; Kärrholm, Johan

2017-05-12

Bone impaction grafting is a biologically and mechanically appealing option in acetabular revision surgery, allowing restitution of the bone stock and restoration of the biomechanics. We analysed differences in proximal migration of the revision acetabular components when bone impaction grafting is used together with a cemented or an uncemented cup. 43 patients (47 hips), revised due to acetabular loosening and judged to have less than 50% host bone-implant contact were included. The hips were randomised to either an uncemented (n = 20) or a cemented (n = 27) revision cup. Radiostereometry and radiography was performed postoperatively, at 3 and 6 months, 1, 2, 3, 5, 7, 10 and 13 and 17 years postoperatively. Clinical follow-up was performed at 1, 2 and 5 years postoperatively and thereafter at the same interval as in the radiographic follow-up. There were no differences in the base line demographic data between the 2 groups. At the last follow-up (17 years) 14 hips (10 cemented, 4 uncemented) had been re-revised due to loosening. 3 additional cups (1 uncemented and 2 cemented) were radiographically loose. There was a higher early proximal migration in the cemented cups. Cups operated on with cement showed a higher early migration measured with RSA and also a higher number of late revisions. The reason for this is not known, but factors such as inclusion of cases with severe bone defects, use of smaller bone chips and issues related to the impaction technique might have had various degrees of influence.

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.

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

A pilot trial comparing the tear-out behavior in screw-sockets and cemented polyethylene acetabular components - a cadaveric study.

PubMed

Möbius, R; Schleifenbaum, S; Grunert, R; Löffler, S; Werner, M; Prietzel, T; Hammer, N

2016-10-01

The removal of well-fixed acetabular components following THA (total hip arthroplasty) is a difficult operation and could be accompanied by the loss of acetabular bone stock. The optimal method for fixation is still under debate. The aim of this pilot study was to compare the tear-out resistance and failure behavior between osseo-integrated and non-integrated screw cups. Furthermore, we examined whether there are differences in the properties mentioned between screw sockets and cemented polyethylene cups. Tear-out resistance and related mechanical work required for the tear-out of osseo-integrated screw sockets are higher than in non-integrated screw sockets. Ten human coxal bones from six cadavers with osseo-integrated screw sockets (n=4), non-integrated (implanted post-mortem, n=3) screw sockets and cemented polyethylene cups (n=3) were used for tear-out testing. The parameters axial failure load and mechanical work for tear-out were introduced as measures for determining the stability of acetabular components following THA. The osseo-integrated screw sockets yielded slightly higher tear-out resistance (1.61±0.26kN) and related mechanical work compared to the non-integrated screw sockets (1.23±0.39kN, P=0.4). The cemented polyethylene cups yielded the lowest tear-out resistance with a failure load of 1.18±0.24kN. Compared to the screw cups implanted while alive, they also differ on a non-significant level (P=0.1). Osseous failure patterns differed especially for the screw sockets compared to the cemented polyethylene cups. Osseo-integration did not greatly influence the tear-out stability in cementless screw sockets following axial loading. Furthermore, the strength of the bone-implant-interface of cementless screw sockets appears to be similar to cemented polyethylene cups. However, given the high failure load, high mechanical load and because of the related bone failure patterns, removal should not be performed by means of tear-out but rather by osteotomes or other curved cutting devices to preserve the acetabular bone stock. Level III, case-control-study. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Ultrasound in Total Hip Replacement: Value of Anterior Acetabular Cup Visibility and Contact With the Iliopsoas Tendon.

PubMed

Guillin, Raphaël; Bertaud, Valérie; Garetier, Marc; Fantino, Olivier; Polard, Jean-Louis; Lambotte, Jean-Christophe

2018-06-01

To assess visibility of the acetabular cup in total hip replacement and to determine the value of direct and indirect signs of iliopsoas impingement syndrome with ultrasound. Ultrasound examinations were performed by a single operator in 17 patients with iliopsoas impingement syndrome and 48 control patients. Cup visibility, contact between the cup and psoas tendon, and the presence of indirect signs of iliopsoas impingement syndrome were investigated in all patients. When the acetabular cup was visible, its size and position in relation to the psoas tendon were recorded. Anterior cup visibility (P = .03), contact with the psoas tendon (P < .001), psoas tendinopathy (P = .02), and iliopsoas bursitis (P < .001) were significantly associated with iliopsoas impingement syndrome, the latter reported with specificity of 100%. In the sagittal plane at the level of the psoas tendon, a maximum sagittal length of greater than 5 mm and a posteroanterior cup shift of 3 mm or greater yielded respective sensitivities of 82% and 59% and specificities of 81% and 100%. When iliopsoas impingement syndrome is clinically suspected, the presence of iliopsoas bursitis or a posteroanterior cup shift of greater than 3 mm under the psoas tendon serve to confirm the diagnosis. In the absence of these conditions, a therapeutic test may be necessary because of the incomplete, albeit high, specificity of other signs. © 2017 by the American Institute of Ultrasound in Medicine.

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 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.

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.

Comparison of Three-Dimensional Planning-Assisted and Conventional Acetabular Cup Positioning in Total Hip Arthroplasty: A Randomized Controlled Trial.

PubMed

Sariali, Elhadi; Boukhelifa, Nadia; Catonne, Yves; Pascal Moussellard, Hugues

2016-01-20

Malpositioning of the acetabular cup during total hip arthroplasty increases the risk of dislocation, edge-loading, squeaking, early wear, and loosening. We hypothesized that the use of three-dimensional (3-D) visualization tools to identify the planned cup position relative to the acetabular edge intraoperatively would increase the accuracy of cup orientation. The purpose of this study was to compare 3-D planning-assisted implantation and freehand insertion of the acetabular cup. This was a prospective randomized controlled study of two groups of twenty-eight patients each. In the first group, cup positioning was guided by 3-D views of the cup within the acetabulum obtained during 3-D preoperative planning. In the control group, the cup was placed freehand. All of the patients were operated on by the same surgeon, through a minimally invasive direct anterior approach with the patient in the supine position. Cup anteversion and abduction angles were measured on 3-D computed tomography (CT) reconstructions. The main evaluation criterion was the percentage of outliers according to the Lewinnek safe zone. Operative time did not differ between the two groups. The cup anteversion was more accurate in the 3-D planning group (mean difference from the planned angle [and standard deviation], -2.7° ± 5.4°) compared with the freehand-placement group (6.6° ± 9.5°). According to the Lewinnek safe zone, overall, the percentage of outliers was lower in the 3-D planning group (21%; six patients) than in the control group (46%; thirteen patients). According to the Callanan safe zone, the percentage of outliers was also lower in the 3-D planning group (25% versus 64%). Although cup abduction was also restored with greater accuracy in the 3-D planning group, on the basis of the Lewinnek safe zone, the percentage of abduction outliers was comparable between groups, with fewer high-abduction values, but more low-abduction values, in the 3-D planning group. Preoperative 3-D planning increased the accuracy of anteversion restoration and reduced the percentage of outliers without increasing the operative time. In this study, the same advantage could not be demonstrated for abduction. Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.

Influence of Surgical Approach on Pelvic Lift in Hip Arthroplasty During Cup Insertion.

PubMed

Brodt, Steffen; Windisch, Christoph; Krakow, Linda; Nowack, Dimitri; Matziolis, Georg

2017-07-01

The position of the acetabular cup is a major factor in the long-term outcome of total hip arthroplasty (THA). Malpositioning of the acetabular cup frequently has been reported with the use of a minimally invasive implantation technique. It remains unclear whether the limited visibility or the increased retractor traction and thus tilting of the pelvis during cup implantation is the cause. This study investigated the influence of iatrogenically related pelvic lift using an anterolateral minimally invasive THA technique. In a group of 30 consecutive patients who underwent THA via a minimally invasive anterolateral approach, iatrogenic lifting of the pelvis was measured with a smartphone using a 3-axis accelerometer and compared with patients in a historical age- and sex-matched control group who underwent THA using a transgluteal approach. Postoperatively, the inclination and anteversion of the cup was determined on pelvic radiographs. In the anterolateral group, the pelvis was lifted by a maximum of 6.3° and by an average of 3.9° when the acetabular cup was impacted; no difference was noted compared with the transgluteal group. In contrast, the cups in the anterolateral group showed significantly increased inclination and reduced anteversion. In both techniques, the iatrogenic tilting of the pelvis at the time of cup implantation occurred to a comparable extent. Therefore, the significant differences in postoperative radiographs cannot be attributed to increased retractor traction on exposure of the acetabulum, which means that the limited visibility must be responsible. [Orthopedics. 2017; 40(4):e589-e593.]. Copyright 2017, SLACK Incorporated.

A 2- to 7-Year Follow-Up of a Modular Iliac Screw Cup in Major Acetabular Defects: Clinical, Radiographic and Survivorship Analysis With Comparison to the Literature.

PubMed

Cadossi, Matteo; Garcia, Flávio Luís; Sambri, Andrea; Andreoli, Isabella; Dallari, Dante; Pignatti, Giovanni

2017-01-01

Inadequate acetabular bone stock is a major issue in total hip arthroplasty, and several treatment options are available. Stemmed cups have been used in this scenario with variable results. A novel modular polyaxial uncemented iliac screw cup (HERM-BS-Sansone cup-Citieffe s.r.l., Calderara di Reno, Bologna, Italy) has been recently introduced to overcome the drawbacks of stemmed cups. In this retrospective study, we report the results of this cup in patients with large acetabular bone defects at 2- to 7-year follow-up. We evaluated a consecutive series of 121 hips (118 revisions and 3 complex primary arthroplasties) treated with this novel cup at a mean follow-up of 46 months. Kaplan-Meier survival analysis was performed with implant revision for any reason as a primary end point. Further survival analysis was performed excluding septic failures. Clinical outcome was assessed with the Harris Hip Score. There had been 7 reoperations: 1 for aseptic loosening, 5 for deep infection, and 1 for recurrent dislocation. In 5 cases, the cup was removed; estimated survival rate at 5-year follow-up with implant removal for any reason was 95.6% (95% confidence interval = 91-99), and 98.3% (95% CI = 96-100) excluding those failed for infection. Mean Harris Hip Score at latest follow-up was 77 points (range, 44-95; standard deviation = 11.9). The present findings show the short-term efficacy of the iliac screw cup with respect to implant survival. A longer follow-up and a larger number of patients are necessary to confirm the encouraging preliminary results. Copyright © 2016 Elsevier Inc. All rights reserved.

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.

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.

Does surface roughness influence the primary stability of acetabular cups? A numerical and experimental biomechanical evaluation.

PubMed

Le Cann, Sophie; Galland, Alexandre; Rosa, Benoît; Le Corroller, Thomas; Pithioux, Martine; Argenson, Jean-Noël; Chabrand, Patrick; Parratte, Sébastien

2014-09-01

Most acetabular cups implanted today are press-fit impacted cementless. Anchorage begins with the primary stability given by insertion of a slightly oversized cup. This primary stability is key to obtaining bone ingrowth and secondary stability. We tested the hypothesis that primary stability of the cup is related to surface roughness of the implant, using both an experimental and a numerical models to analyze how three levels of surface roughness (micro, macro and combined) affect the primary stability of the cup. We also investigated the effect of differences in diameter between the cup and its substrate, and of insertion force, on the cups' primary stability. The results of our study show that primary stability depends on the surface roughness of the cup. The presence of macro-roughness on the peripheral ring is found to decrease primary stability; there was excessive abrasion of the substrate, damaging it and leading to poor primary stability. Numerical modeling indicates that oversizing the cup compared to its substrate has an impact on primary stability, as has insertion force. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

Measuring Acetabular Cup Orientation on Antero-Posterior Radiographs of the Hip after Total Hip Arthroplasty with a Vector Arithmetic Radiological Method. Is It Valid and Verified for Daily Clinical Practice?

PubMed

Craiovan, B; Weber, M; Worlicek, M; Schneider, M; Springorum, H R; Zeman, F; Grifka, J; Renkawitz, T

2016-06-01

The aim of this prospective study is to validate a vector arithmetic method for measuring acetabular cup orientation after total hip arthroplasty (THA) and to verify the clinical practice. We measured cup anteversion and inclination of 123 patients after cementless primary THA twice by two examiners on AP pelvic radiographs with a vector arithmetic method and compared with a 3D-CT based reconstruction model within the same radiographic coronal plane. The mean difference between the radiographic and the 3D-CT measurements was - 1.4° ± 3.9° for inclination and 0.8°± 7.9° for anteversion with excellent correlation for inclination (r = 0.81, p < 0.001) and moderate correlation for anteversion (r = 0.65, p < 0.001). The intraclass correlation coefficient for measurements on radiographs ranged from 0.98 (95 %-CI: 0.98; 0.99) for the first observer to 0.94 (95 %-CI: 0.92; 0.96) for the second observer. The interrater reliability was 0.96 (95 %-CI: 0.93; 0.98) for inclination and 0.93 (95 %-CI: 0.85; 0.96) for anteversion. The largest errors in measurements were associated with an extraordinary pelvic tilt. In order to get a valuable measurement for measuring cup position after THA on pelvic radiographs by this vector arithmetic method, there is a need for a correct postoperative ap view, with special regards to the pelvic tilt for the future. • Measuring acetabular cup orientation on anteroposterior radiographs of the hip after THA is a helpful procedure in everyday clinical practice as a first-line imaging modality• CT remains the golden standard to accurately determine acetabular cup position.• Future measuring on radiographs for cup orientation after THA should account for integration of the pelvic tilt in order to maximize the measurement accuracy. Citation Format: • Craiovan B, Weber M, Worlicek M et al. Measuring Acetabular Cup Orientation on Antero-Posterior Radiographs of the Hip after Total Hip Arthroplasty with a Vector Arithmetic Radiological Method. Is It Valid and Verified for Daily Clinical Practice?. Fortschr Röntgenstr 2016; 188: 574 - 581. © Georg Thieme Verlag KG Stuttgart · New York.

Leg lengthening and femoral-offset reduction after total hip arthroplasty: where is the problem - stem or cup positioning?

PubMed

Al-Amiry, Bariq; Mahmood, Sarwar; Krupic, Ferid; Sayed-Noor, Arkan

2017-09-01

Background Restoration of femoral offset (FO) and leg length is an important goal in total hip arthroplasty (THA) as it improves functional outcome. Purpose To analyze whether the problem of postoperative leg lengthening and FO reduction is related to the femoral stem or acetabular cup positioning or both. Material and Methods Between September 2010 and April 2013, 172 patients with unilateral primary osteoarthritis treated with THA were included. Postoperative leg-length discrepancy (LLD) and global FO (summation of cup and FO) were measured by two observers using a standardized protocol for evaluation of antero-posterior plain hip radiographs. Patients with postoperative leg lengthening ≥10 mm (n = 41) or with reduced global FO >5 mm (n = 58) were further studied by comparing the stem and cup length of the operated side with the contralateral side in the lengthening group, and by comparing the stem and cup offset of the operated side with the contralateral side in the FO reduction group. We evaluated also the inter-observer and intra-observer reliability of the radiological measurements. Results Both observers found that leg lengthening was related to the stem positioning while FO reduction was related to the positioning of both the femoral stem and acetabular cup. Both inter-observer reliability and intra-observer reproducibility were moderate to excellent (intra-class correlation co-efficient, ICC ≥0.69). Conclusion Post THA leg lengthening was mainly caused by improper femoral stem positioning while global FO reduction resulted from improper positioning of both the femoral stem and the acetabular cup.

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.

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.

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.

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.

[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.

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.

Is the cup orientation different in bilateral total hip arthroplasty with right-handed surgeons using posterolateral approach?

PubMed

Song, Xinggui; Ni, Ming; Li, Heng; Li, Xin; Li, Xiang; Fu, Jun; Chen, Jiying

2018-05-23

The impact of surgeon handedness on acetabular cup orientation in total hip arthroplasty (THA) is not well studied. The aim of our study is to investigate the difference of cup orientation in bilateral THA performed by right-handed surgeons using posterolateral approach and which cup could be fitter to Lewinneck's safe zone. The study consisted of 498 patients that underwent bilateral THA by three right-handed surgeons in our hospital. Postoperative acetabular cup anteversion and abduction on an anteroposterior pelvic radiograph were measured by Orthoview software (Orthoview LLC, Jacksonville, Florida). Furthermore, the percentage of cup placement within the safe zone was compared. The mean anteversion was 25.28 (25.28° ± 7.16°) in left THA and 22.01 (22.01° ± 6.35°) in right THA (p < 0.001). The mean abduction was 37.50 (37.50° ± 6.76°) in left THA and 38.59 (38.59° ± 6.84°) in right THA (p = 0.011). In the left side, the cup was positioned in Lewinnek's safe zone in 52% for anteversion, 87% for abduction, and 46% for both anteversion and abduction. But the cup placement within Lewinnek's safe zone was 71, 88, and 62% in the right side, respectively. There were significant differences in the percentage of acetabular cup placement within the safe zone for anteversion (p < 0.001) and for both anteversion and inclination (p < 0.001). Dislocation occurred in 7.0% (35/498) of cases in left THA and 3.2% (16/498) in right THA. The percentages of patients experiencing dislocation were significantly different between the two sides (p = 0.006). This current study demonstrated that surgeon handedness is likely to be a contributing factor that affects cup inclination and anteversion in bilateral THA and that the placement of cup performed by dominant hands of surgeons is more accurate than that performed by non-dominant sides.

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.

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.

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.

Correction of radiographic measurements of acetabular cup wear for variations in pelvis orientation.

PubMed

Derbyshire, Brian

2018-03-01

Radiographic measurement of two-dimensional acetabular cup wear is usually carried out on a series of follow-up radiographs of the patient's pelvis. Since the orientation of the pelvis might not be consistent at every X-ray examination, the resulting change in view of the wear plane introduces error into the linear wear measurement. This effect is amplified on some designs of cup in which the centre of the socket is several millimetres below the centre of the cup or circular wire marker. This study describes the formulation of a mathematical method to correct radiographic wear measurements for changes in pelvis orientation. A mathematical simulation of changes in cup orientation and wear vectors caused by pelvic tilt was used to confirm that the formulae corrected the wear exactly if the radiographic plane of the reference radiograph was parallel to the true plane of wear. An error analysis showed that even when the true wear plane was not parallel to the reference radiographic plane, the formulae could still provide a useful correction. A published correction formula was found to be ineffective.

Correction of radiographic measurements of acetabular cup wear for variations in pelvis orientation

PubMed Central

Derbyshire, Brian

2018-01-01

Radiographic measurement of two-dimensional acetabular cup wear is usually carried out on a series of follow-up radiographs of the patient’s pelvis. Since the orientation of the pelvis might not be consistent at every X-ray examination, the resulting change in view of the wear plane introduces error into the linear wear measurement. This effect is amplified on some designs of cup in which the centre of the socket is several millimetres below the centre of the cup or circular wire marker. This study describes the formulation of a mathematical method to correct radiographic wear measurements for changes in pelvis orientation. A mathematical simulation of changes in cup orientation and wear vectors caused by pelvic tilt was used to confirm that the formulae corrected the wear exactly if the radiographic plane of the reference radiograph was parallel to the true plane of wear. An error analysis showed that even when the true wear plane was not parallel to the reference radiographic plane, the formulae could still provide a useful correction. A published correction formula was found to be ineffective. PMID:29473454

A mathematical method for precisely calculating the radiographic angles of the cup after total hip arthroplasty.

PubMed

Zhao, Jing-Xin; Su, Xiu-Yun; Xiao, Ruo-Xiu; Zhao, Zhe; Zhang, Li-Hai; Zhang, Li-Cheng; Tang, Pei-Fu

2016-11-01

We established a mathematical method to precisely calculate the radiographic anteversion (RA) and radiographic inclination (RI) angles of the acetabular cup based on anterior-posterior (AP) pelvic radiographs after total hip arthroplasty. Using Mathematica software, a mathematical model for an oblique cone was established to simulate how AP pelvic radiographs are obtained and to address the relationship between the two-dimensional and three-dimensional geometry of the opening circle of the cup. In this model, the vertex was the X-ray beam source, and the generatrix was the ellipse in radiographs projected from the opening circle of the acetabular cup. Using this model, we established a series of mathematical formulas to reveal the differences between the true RA and RI cup angles and the measurements results achieved using traditional methods and AP pelvic radiographs and to precisely calculate the RA and RI cup angles based on post-operative AP pelvic radiographs. Statistical analysis indicated that traditional methods should be used with caution if traditional measurements methods are used to calculate the RA and RI cup angles with AP pelvic radiograph. The entire calculation process could be performed by an orthopedic surgeon with mathematical knowledge of basic matrix and vector equations. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Benefit of cup medialization in total hip arthroplasty is associated with femoral anatomy.

PubMed

Terrier, Alexandre; Levrero Florencio, Francesc; Rüdiger, Hannes A

2014-10-01

Medialization of the cup with a respective increase in femoral offset has been proposed in THA to increase abductor moment arms. Insofar as there are potential disadvantages to cup medialization, it is important to ascertain whether the purported biomechanical benefits of cup medialization are large enough to warrant the downsides; to date, studies regarding this question have disagreed. The purpose of this study was to quantify the effect of cup medialization with a compensatory increase in femoral offset compared with anatomic reconstruction for patients undergoing THA. We tested the hypothesis that there is a (linear) correlation between preoperative anatomic parameters and muscle moment arm increase caused by cup medialization. Fifteen patients undergoing THA were selected, covering a typical range of preoperative femoral offsets. For each patient, a finite element model was built based on a preoperative CT scan. The model included the pelvis, femur, gluteus minimus, medius, and maximus. Two reconstructions were compared: (1) anatomic position of the acetabular center of rotation, and (2) cup medialization compensated by an increase in the femoral offset. Passive abduction-adduction and flexion-extension were simulated in the range of normal gait. Muscle moment arms were evaluated and correlated to preoperative femoral offset, acetabular offset, height of the greater trochanter (relative to femoral center of rotation), and femoral antetorsion angle. The increase of muscle moment arms caused by cup medialization varied among patients. Muscle moment arms increase by 10% to 85% of the amount of cup medialization for abduction-adduction and from -35% (decrease) to 50% for flexion-extension. The change in moment arm was inversely correlated (R(2) = 0.588, p = 0.001) to femoral antetorsion (anteversion), such that patients with less femoral antetorsion gained more in terms of hip muscle moments. No linear correlation was observed between changes in moment arm and other preoperative parameters in this series. The benefit of cup medialization is variable and depends on the individual anatomy. Cup medialization with compensatory increase of the femoral offset may be particularly effective in patients with less femoral antetorsion. However, cup medialization must be balanced against its tradeoffs, including the additional loss of medial acetabular bone stock, and eventual proprioceptive implications of the nonanatomic center of rotation and perhaps joint reaction forces. Clinical studies should better determine the relevance of small changes of moment arms on function and joint reaction forces.

Micro X-Ray Computed Tomography Mass Loss Assessment of Different UHMWPE: A Hip Joint Simulator Study on Standard vs. Cross-Linked Polyethylene

PubMed Central

Zanini, Filippo; Carmignato, Simone

2017-01-01

More than 60.000 hip arthroplasty are performed every year in Italy. Although Ultra-High-Molecular-Weight-Polyethylene remains the most used material as acetabular cup, wear of this material induces over time in vivo a foreign-body response and consequently osteolysis, pain, and the need of implant revision. Furthermore, oxidative wear of the polyethylene provoke several and severe failures. To solve these problems, highly cross-linked polyethylene and Vitamin-E-stabilized polyethylene were introduced in the last years. In in vitro experiments, various efforts have been made to compare the wear behavior of standard PE and vitamin-E infused liners. In this study we compared the in vitro wear behavior of two different configurations of cross-linked polyethylene (with and without the add of Vitamin E) vs. the standard polyethylene acetabular cups. The aim of the present study was to validate a micro X-ray computed tomography technique to assess the wear of different commercially available, polyethylene’s acetabular cups after wear simulation; in particular, the gravimetric method was used to provide reference wear values. The agreement between the two methods is documented in this paper. PMID:28107468

Lack of consensus on optimal acetabular cup orientation because of variation in assessment methods in total hip arthroplasty: a systematic review.

PubMed

Snijders, Thom E; Willemsen, Koen; van Gaalen, Steven M; Castelein, Rene M; Weinans, Harrie; de Gast, Arthur

2018-05-01

Dislocation is one of the main reasons for revision of total hip arthroplasty but dislocation rates have not changed in the past decades, compromising patients' well-being. Acetabular cup orientation plays a key role in implant stability and has been widely studied. This article investigates whether there is a consensus on optimal cup orientation, which is necessary when using a navigation system. A systematic search of the literature in the PubMed, Embase and Cochrane databases was performed (March 2017) to identify articles that investigated the direct relationship between cup orientation and dislocation, including a thorough evaluation of postoperative cup orientation assessment methods. Twenty eight relevant articles evaluating a direct relation between dislocation and cup orientation could not come to a consensus. The key reason is a lack of uniformity in the assessment of cup orientation. Cup orientation is assessed with different imaging modalities, different methodologies, different definitions for inclination and anteversion, several reference planes and distinct patient positions. All available studies lack uniformity in cup orientation assessment; therefore it is impossible to reach consensus on optimal cup orientation. Using navigation systems for placement of the cup is inevitably flawed when using different definitions in the preoperative planning, peroperative placement and postoperative evaluation. Further methodological development is required to assess cup orientation. Consequently, the postoperative assessment should be uniform, thus differentiating between anterior and posterior dislocation, use the same definitions for inclination and anteversion with the same reference plane and with the patient in the same position.

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

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.

Factors influencing initial cup stability in total hip arthroplasty.

PubMed

Amirouche, Farid; Solitro, Giovanni; Broviak, Stefanie; Gonzalez, Mark; Goldstein, Wayne; Barmada, Riad

2014-12-01

One of the main goals in total hip replacement is to preserve the integrity of the hip kinematics, by well positioning the cup and to make sure its initial stability is congruent and attained. Achieving the latter is not trivial. A finite element model of the cup-bone interface simulating a realistic insertion and analysis of different scenarios of cup penetration, insertion, under-reaming and loading is investigated to determine certain measurable factors sensitivity to stress-strain outcome. The insertion force during hammering and its relation to the cup penetration during implantation is also investigated with the goal of determining the initial stability of the acetabular cup during total hip arthroplasty. The mathematical model was run in various configurations to simulate 1 and 2mm of under-reaming at various imposed insertion distances to mimic hammering and insertion of cup insertion into the pelvis. Surface contact and micromotion at the cup-bone interface were evaluated after simulated cup insertion and post-operative loading conditions. The results suggest a direct correlation between under-reaming and insertion force used to insert the acetabular cup on the micromotion and fixation at the cup-bone interface. While increased under-reaming and insertion force result in an increase amount of stability at the interface, approximately the same percentage of surface contact and micromotion reduction can be achieved with less insertion force. We need to exercise caution to determine the optimal configuration which achieves a good conformity without approaching the yield strength for bone. Copyright © 2014 Elsevier Ltd. All rights reserved.

Computational assessment of press-fit acetabular implant fixation: the effect of implant design, interference fit, bone quality, and frictional properties.

PubMed

Janssen, D; Zwartelé, R E; Doets, H C; Verdonschot, N

2010-01-01

Patients suffering from rheumatoid arthritis typically have a poor subchondral bone quality, endangering implant fixation. Using finite element analysis (FEA) an investigation was made to find whether a press-fit acetabular implant with a polar clearance would reduce interfacial micromotions and improve fixation compared with a standard hemispherical design. In addition, the effects of interference fit, friction, and implant material were analysed. Cups were introduced into an FEA model of a human pelvis with simulated subchondral bone plasticity. The models were loaded with a loading configuration simulating two cycles of normal walking, during which contact stresses and interfacial micromotions were monitored. Subsequently, a lever-out simulation was performed to assess the fixation strength of the various cases. A flattened cup with good bone quality produced the lowest interfacial micromotions. Poor bone decreased the fixation strength regardless of the geometry of the cup. Increasing the interference fit of the flattened cup compensated for the loss of fixation strength caused by poor bone quality. In conclusion, a flattened cup did not significantly improve implant fixation over a hemispherical cup in the case of poor bone quality. However, implant fixation can be optimized by increasing interference fit and avoiding inferior frictional properties and low-stiffness implants.

Segmental acetabular rim defects, bone loss, oversizing, and press fit cup in total hip arthroplasty evaluated with a probabilistic finite element analysis.

PubMed

Amirouche, Farid; Solitro, Giovanni F; Walia, Amit; Gonzalez, Mark; Bobko, Aimee

2017-08-01

Management of segmental rim defects and bone mineral density (BMD) loss in the elderly prior to total hip replacement is unclear within classification systems for acetabular bone loss. In this study, our objectives were (1) to understand how a reduction in BMD in the elderly affects the oversizing of a press-fit cup for primary fixation and (2) to evaluate whether the location of the segmental defect affected cup fixation. A finite element (FE) model was used to simulate and evaluate cup insertion and fixation in the context of segmental rim defects. We focused on the distribution of patients over age 70 and used BMD (estimated from CT) as a proxy for aging's implications on THR and used probabilistic FE analysis to understand how BMD loss affects oversizing of a press-fit cup. A cup oversized by 1.10 ± 0.28 mm provides sufficient fixation and lower stresses at the cup-bone interface for elderly patients. Defects in the anterior column and posterior column both required the same mean insertion force for cup seating of 84% (taken as an average of 2 anterior column and 2 posterior column defects) compared to the control configuration, which was 5% greater than the insertion force for a superior rim defect and 12% greater than the insertion force for an inferior rim defect. A defect along the superior or inferior rim had a minimal effect on cup fixation, while a defect in the columns created cup instability and increased stress at the defect location.

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.

Assessment of Accuracy and Reliability in Acetabular Cup Placement Using an iPhone/iPad System.

PubMed

Kurosaka, Kenji; Fukunishi, Shigeo; Fukui, Tomokazu; Nishio, Shoji; Fujihara, Yuki; Okahisa, Shohei; Takeda, Yu; Daimon, Takashi; Yoshiya, Shinichi

2016-07-01

Implant positioning is one of the critical factors that influences postoperative outcome of total hip arthroplasty (THA). Malpositioning of the implant may lead to an increased risk of postoperative complications such as prosthetic impingement, dislocation, restricted range of motion, polyethylene wear, and loosening. In 2012, the intraoperative use of smartphone technology in THA for improved accuracy of acetabular cup placement was reported. The purpose of this study was to examine the accuracy of an iPhone/iPad-guided technique in positioning the acetabular cup in THA compared with the reference values obtained from the image-free navigation system in a cadaveric experiment. Five hips of 5 embalmed whole-body cadavers were used in the study. Seven orthopedic surgeons (4 residents and 3 senior hip surgeons) participated in the study. All of the surgeons examined each of the 5 hips 3 times. The target angle was 38°/19° for operative inclination/anteversion angles, which corresponded to radiographic inclination/anteversion angles of 40°/15°. The simultaneous assessment using the navigation system showed mean±SD radiographic alignment angles of 39.4°±2.6° and 16.4°±2.6° for inclination and anteversion, respectively. Assessment of cup positioning based on Lewinnek's safe zone criteria showed all of the procedures (n=105) achieved acceptable alignment within the safe zone. A comparison of the performances by resident and senior hip surgeons showed no significant difference between the groups (P=.74 for inclination and P=.81 for anteversion). The iPhone/iPad technique examined in this study could achieve acceptable performance in determining cup alignment in THA regardless of the surgeon's expertise. [Orthopedics. 2016; 39(4):e621-e626.]. Copyright 2016, SLACK Incorporated.

Patient Obesity Influences Pelvic Lift During Cup Insertion in Total Hip Arthroplasty Through a Lateral Transgluteal Approach in Supine Position.

PubMed

Brodt, Steffen; Nowack, Dimitri; Jacob, Benjamin; Krakow, Linda; Windisch, Christoph; Matziolis, Georg

2017-09-01

Movement of the pelvis during implantation of total hip arthroplasty (THA) has a major influence on the positioning of the acetabular cup. Strong traction caused by retractors leads to iatrogenic pelvic lift and can thus be partly responsible for cup malpositioning. The objective of this study was to investigate such factors that influence pelvic lift. The dynamic movement of the pelvis was measured during implantation of THA in 67 patients. This was done by measuring the acceleration using the SensorLog app on a smartphone. At its maximum, the pelvis was lifted by an average of 6.7°. When impacting the press-fit cup, the surgical side was raised by 4.4° compared with the time of skin incision. This lift at the time of cup implantation correlates significantly with the body mass index and the patient's abdominal and pelvic circumference. Every surgeon performing THA must be aware of the pelvic lift during an operation. Especially in patients with a high body mass index, a large abdominal circumference, or a large pelvic circumference, there is an increased risk of malpositioning of the acetabular cup. When impacting the cup, we recommend releasing the traction of the retractor, so that the pelvis can tilt back into its natural position, and thus, the anticipated cup positioning can be implemented as exactly as possible. Copyright © 2017 Elsevier Inc. All rights reserved.

Quantification of Wear and Deformation in Different Configurations of Polyethylene Acetabular Cups Using Micro X-ray Computed Tomography

PubMed Central

Affatato, Saverio; Zanini, Filippo; Carmignato, Simone

2017-01-01

Wear is currently quantified as mass loss of the bearing materials measured using gravimetric methods. However, this method does not provide other information, such as volumetric loss or surface deviation. In this work, we validated a technique to quantify polyethylene wear in three different batches of ultrahigh-molecular-polyethylene acetabular cups used for hip implants using nondestructive microcomputed tomography. Three different configurations of polyethylene acetabular cups, previously tested under the ISO 14242 parameters, were tested on a hip simulator for an additional 2 million cycles using a modified ISO 14242 load waveform. In this context, a new approach was proposed in order to simulate, on a hip joint simulator, high-demand activities. In addition, the effects of these activities were analyzed in terms of wear and deformations of those polyethylenes by means of gravimetric method and micro X-ray computed tomography. In particular, while the gravimetric method was used for weight loss assessment, microcomputed tomography allowed for acquisition of additional quantitative information about the evolution of local wear and deformation through three-dimensional surface deviation maps for the entire cups’ surface. Experimental results showed that the wear and deformation behavior of these materials change according to different mechanical simulations. PMID:28772616

Increased migration of uncemented acetabular cups in female total hip arthroplasty patients with low systemic bone mineral density. A 2-year RSA and 8-year radiographic follow-up study of 34 patients.

PubMed

Finnilä, Sami; Moritz, Niko; SvedströM, Erkki; Alm, Jessica J; Aro, Hannu T

2016-02-01

Low bone mineral density (BMD) may jeopardize the initial component stability and delay osseointegration of uncemented acetabular cups in total hip arthroplasty (THA). We measured the migration of uncemented cups in women with low or normal BMD. We used radiostereometric analysis (RSA) to measure the migration of hydroxyapatite-coated titanium alloy cups with alumina-on-alumina bearings in THA of 34 female patients with a median age of 64 (41-78) years. 10 patients had normal BMD and 24 patients had low systemic BMD (T-score ≤ -1) based on dual-energy X-ray absorptiometry (DXA). Cup migration was followed with RSA for 2 years. Radiographic follow-up was done at a median of 8 (2-10) years. Patients with normal BMD did not show a statistically significant cup migration after the settling period of 3 months, while patients with low BMD had a continuous proximal migration between 3 and 12 months (p = 0.03). These differences in cup migration persisted at 24 months. Based on the perceived risk of cup revision, 14 of the 24 cases were "at risk" (proximal translation of 0.2 to 1.0 mm) in the low-BMD group and 2 of the 10 cases were "at risk" in the normal-BMD group (odds ratio (OR) = 8.0, 95% CI: 1.3-48). The radiographic follow-up showed no radiolucent lines or osteolysis. 2 cups have been revised for fractures of the ceramic bearings, but none for loosening. Low BMD contributed to cup migration beyond the settling period of 3 months, but the migrating cups appeared to osseointegrate eventually.

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

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.

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.

Central X-ray beam correction of radiographic acetabular cup measurement after THA: an experimental study.

PubMed

Schwarz, T; Weber, M; Wörner, M; Renkawitz, T; Grifka, J; Craiovan, B

2017-05-01

Accurate assessment of cup orientation on postoperative radiographs is essential for evaluating outcome after THA. However, accuracy is impeded by the deviation of the central X-ray beam in relation to the cup and the impossibility of measuring retroversion on standard pelvic radiographs. In an experimental trial, we built an artificial cup holder enabling the setting of different angles of anatomical anteversion and inclination. Twelve different cup orientations were investigated by three examiners. After comparing the two methods for radiographic measurement of the cup position developed by Lewinnek and Widmer, we showed how to differentiate between anteversion and retroversion in each cup position by using a second plane. To show the effect of the central beam offset on the cup, we X-rayed a defined cup position using a multidirectional central beam offset. According to Murray's definition of anteversion and inclination, we created a novel corrective procedure to balance measurement errors caused by deviation of the central beam. Measurement of the 12 different cup positions with the Lewinnek's method yielded a mean deviation of [Formula: see text] (95 % CI 1.3-2.3) from the original cup anteversion. The respective deviation with the Widmer/Liaw's method was [Formula: see text] (95 % CI 2.4-4.0). In each case, retroversion could be differentiated from anteversion with a second radiograph. Because of the multidirectional central beam offset ([Formula: see text] cm) from the acetabular cup in the cup holder ([Formula: see text] anteversion and [Formula: see text] inclination), the mean absolute difference for anteversion was [Formula: see text] (range [Formula: see text] to [Formula: see text] and [Formula: see text] (range [Formula: see text] to [Formula: see text] for inclination. The application of our novel mathematical correction of the central beam offset reduced deviation to a mean difference of [Formula: see text] for anteversion and [Formula: see text] for inclination. This novel calculation for central beam offset correction enables highly accurate measurement of the cup position.

Wear Behaviours and Oxidation Effects on Different UHMWPE Acetabular Cups Using a Hip Joint Simulator

PubMed Central

Jaber, Sami Abdel; Merola, Massimiliano

2018-01-01

Given the long-term problem of polyethylene wear, medical interest in the new improved cross-linked polyethylene (XLPE), with or without the adding of vitamin E, has risen. The main aim of this study is to gain further insights into the mutual effects of radiation cross-linking and addition of vitamin E on the wear performance of ultra-high-molecular-weight polyethylene (UHMWPE). We tested four different batches of polyethylene (namely, a standard one, a vitamin E-stabilized, and two cross-linked) in a hip joint simulator for five million cycles where bovine calf serum was used as lubricant. The acetabular cups were then analyzed using a confocal profilometer to characterize the surface topography. Moreover; the cups were analyzed by using Fourier Transformed Infrared Spectroscopy and Differential Scanning Calorimetry in order to assess the chemical characteristics of the pristine materials. Comparing the different cups’ configuration, mass loss was found to be higher for standard polyethylene than for the other combinations. Mass loss negatively correlated to the cross-link density of the polyethylenes. None of the tested formulations showed evidence of oxidative degradation. We found no correlation between roughness parameters and wear. Furthermore, we found significantly differences in the wear behavior of all the acetabular cups. XLPEs exhibited lower weight loss, which has potential for reduced wear and decreased osteolysis. However, surface topography revealed smoother surfaces of the standard and vitamin E stabilized polyethylene than on the cross-linked samples. This observation suggests incipient crack generations on the rough and scratched surfaces of the cross-linked polyethylene liners. PMID:29547536

A Kirschner wire as a transverse-axis guide to improve acetabular cup positioning.

PubMed

Ishidou, Y; Hirotsu, M; Setoguchi, T; Nagano, S; Kakoi, H; Yokouchi, M; Yamamoto, T; Komiya, S

2016-04-01

To compare cup-positioning accuracy in total hip arthroplasty (THA) with or without use of a Kirschner wire as a transverse-axis guide for pelvic alignment. Records of 18 men and 73 women (mean age, 60 years) who underwent primary THA with (n=49) or without (n=42) use of a Kirschner wire as a transverse-axis guide for pelvic alignment were reviewed. A 2.4-mm Kirschner wire as a transversea-xis guide was inserted to the anterior superior iliac spine and was parallel to a line linking the left and right anterior superior iliac spine. The safe zone for cup positioning was defined as 30º to 50° abduction and 10º to 30º anteversion. Of the 5 operative surgeons, 2 were classified as experienced (total surgical volume >300) and 3 as inexperienced (total surgical volume of <50). The proportion of patients with the cup in the safe zone was compared in patients with or without use of the transverse-axis guide and in experienced and inexperienced surgeons. For inexperienced surgeons, the use of the transverse-axis guide significantly improved the proportion of patients with the cup in the safe zone from 90% to 100% for abduction, from 50% to 82.4% for anteversion, and from 40% to 82.4% for both. Patients with the cup inside or outside the safe zone were comparable in terms of body height, weight, BMI, subcutaneous fat thickness, incision length, and acetabular cup size. The use of the transverse-axis guide improved the accuracy of cup positioning by inexperienced surgeons.

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.

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

Migration characteristics and early clinical results of a novel-finned press-fit acetabular cup.

PubMed

Kaipel, Martin; Prenner, Anton; Bachl, Sebastian; Farr, Sebastian; Sinz, Günter

2014-04-01

Ana Nova® is a novel-finned press-fit acetabular cup which showed superior biomechanical characteristics in an experimental set-up. Using Einzel Bild Röntgen Analyse (EBRA) measurements should offer the opportunity to predict implant survival at an early stage. The purpose of this study was to assess migration and clinical outcome 2 years after total hip replacement by a novel-finned press-fit acetabular cup. In this study, migration and clinical results of the implant were prospectively assessed in 67 patients. Clinical outcome was assessed using the Harris hip score (HHS). Migration analyses were performed using the computer assisted EBRA system. Data were analyzed for normal distribution using the Kolmogorov-Smirnov test. Group comparisons were performed using the analysis of variance (ANOVA) test. P-values less than 0.05 were considered statistically significant. At 2 years after surgery, none of the implants needed revision and HHS increased from 39.7 up to 92.2. In contrast to the beneficial clinical outcome, 17 of 44 patients showed increased total migration ( 1 mm/2a). Adverse migration data in this study might predict aseptic loosening and decreased survival of the implant. According to previous studies, it is possible that this effect occurred because of limited accuracy of the EBRA system. In our opinion, migration analyses may not be recommended as a screening tool in a 2 year follow-up.

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.

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.

[Radiographic appraisal between metal and bone interosculate backfill after total hip arthroplasty with trabecular metal cup].

PubMed

Li, Wei; Zhou, Yi-Xin; Wu, Jian; Xu, Hui; Ji, Song-Jie

2009-02-15

To evaluate the bone refilling in the interface between the trabecular metal (TM) acetabular shell and the bone surface according to consecutive X film measuring after surgery. From July 2006 to July 2007, 35 patients (40 hips) accepted total hip replacement using trabecular metal monoblock acetabular cup system (TM). The cup was made of a ellipse shaped press fit Tantalum shell and high cross-linked PE liner (Longevity) with 28 mm inner diameter. The patients demography was: 16 male (20 hips), 19 female (20 hips), 5 bilateral hip replacements, age from 41 - 71 (mean 53), including 18 avascular necrosis hips, 16 osteoarthritis hips (including those secondary to a dysplasia hip), 4 avascular necrosis hips after femoral neck fracture, 2 Ankylosis Spondylitis. All the 40 total hip replacements used posterior approach, using hemispherical acetabular reamer and 2 mm press fit of final metal shell without screw fixation. The consecutive X film was taken at the end time of surgery and 2, 6, 12, 24 weeks, and 12 months. The clinical results was evaluate according to Harris scoring system, and the standard pelvis AP X film was measured at the interface between metal shell and the acetabular bone surface, witch was divided into five regions (A, B, C, D, E). Totally 32 patients (37 hips) were followed with average 8.7 months (7 - 12 months). The Harris before surgery was 50.5 (32 - 85), promoted to 91.0 (72 - 100), including 29 excellent, 6 good, 2 fair, and the total excellent and good rate was 94.6%. Complications include 4 patients leg length discrepancy from 1 - 2 cm, 3 patients moderate thigh pain and released after conservative therapy. No infection and dislocation was found. Twenty-one patients (23 hips) were found lucent line at the bone-metal interface from 1 - 5 mm, most common in B region and BC boundary than C, D, and CD boundary. All the patients followed was found the lucent line disappeared and refilled with bone at X film 24 weeks after surgery, however, no patients was found osteolysis and cup migration. The trabecular metal has strong capacity of bone conductive and bone inducement.

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.

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.

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

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.

[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.

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

The transport of wear particles in the prosthetic hip joint: a computational fluid dynamics investigation.

PubMed

Hölzer, Andreas; Schröder, Christian; Woiczinski, Matthias; Sadoghi, Patrick; Müller, Peter E; Jansson, Volkmar

2012-02-02

The joint fluid mechanics and transport of wear particles in the prosthetic hip joint were analyzed for subluxation and flexion motion using computational fluid dynamics (CFD). The entire joint space including a moving capsule boundary was considered. It was found that particles suspended in the joint space are drawn into the joint gap between prosthesis cup and head during subluxation, which was also documented by Lundberg et al. (2007; Journal of Biomechanics 40, 1676-1685), however, wear particles remain in the joint gap. Wear particles leave the joint gap during flexion and can finally migrate to the proximal boundaries including the acetabular bone, where the particle deposition can cause osteolysis according to the established literature. Thus, the present study supports the theory of polyethylene wear particle induced osteolysis of the acetabular bone as a major factor in the loosening of hip prosthesis cups. Copyright © 2011 Elsevier Ltd. All rights reserved.

[The Use of Jumbo Cups in Revision Total Hip Arthroplasty].

PubMed

von Roth, Philipp; Wassilew, Georgi I

2017-10-01

Extra-large uncemented jumbo cups are among the most common methods of acetabular revision. Jumbo cups do not contribute to bone stock restoration, and in the case of a subsequent revision, an even larger bone defect is to be expected. Thus, understanding long-term survival is essential. The present article discusses the literature relevant to this topic and addresses technical and implant-specific characteristics of jumbo cups. In summary, jumbo cups show an acceptable long-term survival rate, with aseptic loosening as the most common reason for revision and dislocation being the most common complication. Through the development of alternative revision systems, jumbo cups have lost their importance in today's practice. However, they can serve as a benchmark for studies of newer technologies in revision total hip arthroplasty. Georg Thieme Verlag KG Stuttgart · New York.

[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.

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.

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

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.

A hip joint simulator study using new and physiologically scratched femoral heads with ultra-high molecular weight polyethylene acetabular cups.

PubMed

Barbour, P S; Stone, M H; Fisher, J

2000-01-01

This study validates a hip joint simulator configuration as compared with other machines and clinical wear rates using smooth metal and ceramic femoral heads and ultra-high molecular weight polyethylene (UHMWPE) acetabular cups. Secondly the wear rate of UHMWPE cups is measured in the simulator with deliberately scratched cobalt-chrome heads to represent the type of mild and severe scratch damage found on retrieved heads. Finally, the scratching processes are described and the resulting scratches compared with those found in retrieved cobalt-chrome heads. For smooth cobalt-chrome and zirconia heads the wear rates were found to be statistically similar to other simulator machines and within the normal range found from clinical studies. An increased wear rate was found with cobalt-chrome heads scratched using either the diamond stylus or the bead cobalt-chrome but the greatest increase was with the diamond scratched heads which generated scratches of similar dimensions to those on retrieved heads. A greater than twofold increase in wear rate is reported for these heads when compared with smooth heads. This increased wear rate is, however, still within the limits of data from clinical wear studies.

Effects of hydroxyapatite coating of cups used in hip revision arthroplasty

PubMed Central

2012-01-01

Background and purpose Coating of acetabular revision implants with hydroxyapatite (HA) has been proposed to improve ingrowth and stability. We investigated whether HA coating of revision cups can reduce the risk of any subsequent re-revision. Methods We studied uncemented cups either with or without HA coating that were used at a primary acetabular revision and registered in the Swedish Hip Arthroplasty Register (SHAR). 2 such cup designs were identified: Harris-Galante and Trilogy, both available either with or without HA coating. These cups had been used as revision components in 1,780 revisions of total hip arthroplasties (THA) between 1986 and 2009. A Cox proportional hazards model including the type of coating, age at index revision, sex, cause of cup revision, cup design, the use of bone graft at the revision procedure, and the type of cup fixation at primary THA were used to calculate adjusted risk ratios (RRs with 95% CI) for re-revision for any reason or due to aseptic loosening. Results 71% of the cups were coated with HA and 29% were uncoated. At a mean follow-up time of 6.9 (0–24) years, 159 (9%) of all 1,780 cups had been re-revised, mostly due to aseptic loosening (5%), dislocation (2%), or deep infection (1%). HA coating had no significant influence on the risk of re-revision of the cup for any reason (RR = 1.4, CI: 0.9–2.0) or due to aseptic loosening (RR = 1.1, 0.6–1.9). In contrast, HA coating was found to be a risk factor for isolated liner re-revision for any reason (RR = 1.8, CI: 1.01–3.3). Age below 60 years at the index cup revision, dislocation as the cause of the index cup revision, uncemented cup fixation at primary THA, and use of the Harris-Galante cup also increased the risk of re-revision of the cup. In separate analyses in which isolated liner revisions were excluded, bone grafting was found to be a risk factor for re-revision of the metal shell due to aseptic loosening (RR = 2.1, CI: 1.05–4.2). Interpretation We found no evidence to support the notion that HA coating improves the performance of the 2 studied cup designs in revision arthroplasty. In contrast, patient-related factors such as younger age and dislocation as the reason for cup revision, and technical factors such as the choice of revision cup were found to influence the risk of subsequent re-revision of the cup. The reason for inferior results after revision of uncemented cups is not known, but it is possible that these hips more often had pronounced bone loss at the index cup revision. PMID:22937978

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.

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.

Nuclear fuel element nut retainer cup. [PWR

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

Walton, L.A.

1977-07-19

A typical embodiment has an end fitting for a nuclear reactor fuel element that is joined to the control rod guide tubes by means of a nut plate assembly. The nut plate assembly has an array of nuts, each engaging the respective threaded end of the control rod guide tubes. The nuts, moreover, are retained on the plate during handling and before fuel element assembly by means of hollow cylindrical locking cups that are brazed to the plate and loosely circumscribe the individual enclosed nuts. After the nuts are threaded onto the respective guide tube ends, the locking cups aremore » partially deformed to prevent one or more of the nuts from working loose during reactor operation. The locking cups also prevent loose or broken end fitting parts from becoming entrained in the reactor coolant.« less

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.

Migration of the Duraloc cup after 5 years.

PubMed

Stihsen, Christoph; Pabinger, Christof; Radl, Roman; Rehak, Peter; Windhager, Reinhard

2008-12-01

The Duraloc cup is a frequently used metal-backed, porous-coated, hemispherical, press-fit acetabular component. Published data on loosening rates are contradictory. In this study we investigated migration patterns with computer-assisted Einzel-Bild-Roentgen-Analyse (EBRA) of 67 Duraloc 100 cups. Cup migration and clinical scores were analysed over a 5-year follow-up period. Median total migration of the Duraloc 100 cup was 1.21 mm at 5 years. Seventy-five percent of implants were radiologically stable at 2 years and 90% at 4 years. One cup loosened aseptically at 60 months, requiring revision. Cup diameters > or = 54 mm migrated significantly more than cups < 54 mm in diameter (p = 0.029 at 4 years). There was a significant correlation between high polyethylene wear and further migrating cups within the first post-operative year (p = 0.035 at 12 months). Our analysis revealed significantly higher wear in males (p = 0.029 at 4 years). Radiological loosening at two years could be calculated using receiver-operating characteristic curve analysis, and 1.2 mm as an adequate threshold value (sensitivity = 100%, specificity = 89%).

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.

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.

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.

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.

Combined chemical and mechanical effects on free radicals in UHMWPE joints during implantation.

PubMed

Jahan, M S; Wang, C; Schwartz, G; Davidson, J A

1991-08-01

An electron spin resonance (ESR) technique is employed to determine the free radical distribution in the articulating surfaces of retrieved acetabular cups and knee-joint plateaus (retrieved after more than 6 years of implantation). Similar measurements made on samples prepared from cyclically stressed and unstressed cups, and on samples following oxidations in nitric acid and intralipid solutions provided sufficient data to gain more knowledge about the combined chemical and mechanical effects on PE free radicals during implantation. In UHMWPE free radicals are primarily initiated by gamma-ray sterilization; however, during implantation, peroxy (scission type) free radicals are formed and reach a maximum concentration level (equilibrium state) due to oxidation by chemical (hemoglobin and/or synovial fluids) environment of the joints. Subsequently, due to frictional heating and stress in the loading zones, free radical reaction is accelerated and their number is reduced only in those areas. This is consistent with the observations of a temperature rise in acetabular cups during in vitro frictional wear stress tests and in vivo telemetry observations, as reported by others. Compared with the previously reported SEM micrographs the low-free-radical regions are correlated with high-wear areas and the high-free-radical regions with the low-wear areas.

Do screws and screw holes affect osteolysis in cementless cups using highly crosslinked polyethylene? A 7 to 10-year follow-up case-control study.

PubMed

Taniguchi, N; Jinno, T; Takada, R; Koga, D; Ando, T; Okawa, A; Haro, H

2018-05-01

The use of screws and the presence of screw holes may cause acetabular osteolysis and implant loosening in cementless total hip arthroplasty (THA) using conventional polyethylene. In contrast, this issue is not fully understood using highly crosslinked polyethylene (HXLPE), particularly in large comparative study. Therefore, we performed a case-control study to assess the influence of screw usage and screw holes on: (1) implant fixation and osteolysis and (2) polyethylene steady-state wear rate, using cases with HXLPE liners followed up for 7-10 years postoperatively. The screw usage and screw holes adversely affect the implant fixation and incidence of wear-related osteolysis in THA with HXLPE. We reviewed 209 primary cementless THAs performed with 26-mm cobalt-chromium heads on HXLPE liners. To compare the effects of the use of screws and the presence of screw holes, the following groups were established: (1) with-screw (n=140); (2) without-screw (n=69); (3) no-hole (n=27) and (4) group in which a cup with screw holes, but no screw was used (n=42). Two adjunct groups (no-hole cups excluded) were established to compare the differences in the two types of HXLPE: (5) remelted group (n=100) and (6) annealed group (n=82). Implant stability and osteolysis were evaluated by plain radiography and computed tomography. The wear rate from 1 year to the final evaluation was measured using plain X-rays and PolyWare Digital software. All cups and stems achieved bony fixation. On CT-scan, no acetabular osteolysis was found, but there were 3 cases with a small area of femoral osteolysis. The mean steady-state wear rate of each group was (1) 0.031±0.022, (2) 0.033±0.035, (3) 0.031±0.024, (4) 0.029±0.018, (5) 0.030±0.018 and (6) 0.034±0.023mm/year, respectively. A comparison of the effects of screw usage or screw holes found no significant between-group differences in the implant stability, prevalence of osteolysis [no acetabular osteolysis and 3/209 at femoral side (1.4%)] and steady-state wear rate. This study suggests that there are no adverse effects on the results of THA with HXLPE from the use of cups with screw holes and the use of screws for cup fixation. Level III retrospective case-control study. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

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.

Tailor-made Surgical Guide Reduces Incidence of Outliers of Cup Placement.

PubMed

Hananouchi, Takehito; Saito, Masanobu; Koyama, Tsuyoshi; Sugano, Nobuhiko; Yoshikawa, Hideki

2010-04-01

Malalignment of the cup in total hip arthroplasty (THA) increases the risks of postoperative complications such as neck cup impingement, dislocation, and wear. We asked whether a tailor-made surgical guide based on CT images would reduce the incidence of outliers beyond 10 degrees from preoperatively planned alignment of the cup compared with those without the surgical guide. We prospectively followed 38 patients (38 hips, Group 1) having primary THA with the conventional technique and 31 patients (31 hips, Group 2) using the surgical guide. We designed the guide for Group 2 based on CT images and fixed it to the acetabular edge with a Kirschner wire to indicate the planned cup direction. Postoperative CT images showed the guide reduced the number of outliers compared with the conventional method (Group 1, 23.7%; Group 2, 0%). The surgical guide provided more reliable cup insertion compared with conventional techniques. Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Migration of the Duraloc cup after 5 years

PubMed Central

Stihsen, Christoph; Pabinger, Christof; Radl, Roman; Rehak, Peter

2007-01-01

The Duraloc cup is a frequently used metal-backed, porous-coated, hemispherical, press-fit acetabular component. Published data on loosening rates are contradictory. In this study we investigated migration patterns with computer-assisted Einzel-Bild-Roentgen-Analyse (EBRA) of 67 Duraloc 100 cups. Cup migration and clinical scores were analysed over a 5-year follow-up period. Median total migration of the Duraloc 100 cup was 1.21 mm at 5 years. Seventy-five percent of implants were radiologically stable at 2 years and 90% at 4 years. One cup loosened aseptically at 60 months, requiring revision. Cup diameters ≥54 mm migrated significantly more than cups <54 mm in diameter (p = 0.029 at 4 years). There was a significant correlation between high polyethylene wear and further migrating cups within the first post-operative year (p = 0.035 at 12 months). Our analysis revealed significantly higher wear in males (p = 0.029 at 4 years). Radiological loosening at two years could be calculated using receiver-operating characteristic curve analysis, and 1.2 mm as an adequate threshold value (sensitivity = 100%, specificity = 89%). PMID:17609953

Roentgen stereophotogrammetric analysis of metal-backed hemispherical cups without attached markers.

PubMed

Valstar, E R; Spoor, C W; Nelissen, R G; Rozing, P M

1997-11-01

A method for the detection of micromotion of a metal-backed hemispherical acetabular cup is presented and tested. Unlike in conventional roentgen stereophotogrammetric analysis, the cup does not have to be marked with tantalum markers; the micromotion is calculated from the contours of the hemispherical part and the base circle of the cup. In this way, two rotations (tilt and anteversion) and the translations along the three cardinal axes are obtained. In a phantom study, the maximum error in the position of the cup's centre was 0.04 mm. The mean error in the orientation of the cup was 0.41 degree, with a 95% confidence interval of 0.28-0.54 degree. The in vivo accuracy was tested by repeated measurement of 21 radiographs from seven patients. The upper bound of the 95% tolerance interval for the translations along the transversal, longitudinal, and sagittal axes was 0.09, 0.07, and 0.34 mm, respectively: for the rotation, this upper bound was 0.39 degree. These results show that the new method, in which the position and orientation of metal-backed hemispherical cup is calculated from its projected contours, is a simple and accurate alternative to attaching markers to the cup.

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.

Load Transmission Through Artificial Hip Joints due to Stress Wave Loading

NASA Astrophysics Data System (ADS)

Tanabe, Y.; Uchiyama, T.; Yamaoka, H.; Ohashi, H.

Since wear of the polyethylene (Ultra High Molecular Weight Polyethylene or UHMWPE) acetabular cup is considered to be the main cause of loosening of the artificial hip joint, the cross-linked UHMWPE with high durability to wear has been developed. This paper deals with impact load transmission through the complex of an artificial hip joint consisting of a UHMWPE acetabular cup (or liner), a metallic femoral head and stem. Impact compressive tests on the complex were performed using the split-Hopkinson pressure bar apparatus. To investigate the effects of material (conventional or cross-linked UHMWPE), size and setting angle of the liner, and test temperature on force transmission, the impact load transmission ratio (ILTR) was experimentally determined. The ILTR decreased with an increase of the setting angle independent of material and size of the liner, and test temperature. The ILTR values at 37°C were larger than those at 24 °C and 60°C. The ILTR also appeared to be affected by the type of material as well as size of the liner.

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.

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.

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.

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.

Wear performance of neat and vitamin E blended highly cross-linked PE under severe conditions: The combined effect of accelerated ageing and third body particles during wear test.

PubMed

Affatato, Saverio; De Mattia, Jonathan Salvatore; Bracco, Pierangiola; Pavoni, Eleonora; Taddei, Paola

2016-12-01

The objective of this study is to evaluate the effects of third-body particles on the in vitro wear behaviour of three different sets of polyethylene acetabular cups after prolonged testing in a hip simulator and accelerated ageing. Vitamin E-blended, cross-linked polyethylene (XLPE_VE), cross-linked polyethylene (XLPE) and conventional polyethylene (STD_PE) acetabular cups were simulator tested for two million cycles under severe conditions (i.e. by adding third-body particles to the bovine calf serum lubricant). Micro-Fourier Transform Infrared and micro-Raman spectroscopic analyses, differential scanning calorimetry, and crosslink density measurements were used to characterize the samples at a molecular level. The STD_PE cups had twice mass loss than the XLPE_VE components and four times than the XLPE samples; statistically significant differences were found between the mass losses of the three sets of cups. The observed wear trend was justified on the basis of the differences in cross-link density among the samples (XLPE>XLPE_VE>STD_PE). FTIR crystallinity profiles, bulk DSC crystallinity and surface micro-Raman crystallinity seemed to have a similar behaviour upon testing: all of them (as well as the all-trans and ortho-trans contents) revealed the most significant changes in XLPE and XLPE_VE samples. The more severe third-body wear testing conditions determined more noticeable changes in all spectroscopic markers with respect to previous tests. Unexpectedly, traces of bulk oxidation were found in both STD_PE (unirradiated) and XLPE (remelting-stabilized), which were expected to be stable to oxidation; on the contrary, XLPE_VE demonstrated a high oxidative stability in the present, highly demanding conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

[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.

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.

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.

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.

Influence of cup-center-edge angle on micro-motion at the interface between the cup and host bone in cementless total hip arthroplasty: three-dimensional finite element analysis.

PubMed

Kaku, Nobuhiro; Tabata, Tomonori; Tsumura, Hiroshi

2015-12-01

We verified the index cup position required for bulk bone grafting instead of morcellized grafting immediately after cementless total hip arthroplasty. Three-dimensional finite element analysis was used to evaluate changes in the volume of the slippage of the cup-host bone interface as micro-motion of the cup at the acetabular bone defect site depending on the cup-center-edge (CE) angle. The conditions of bulk bone grafts were similar to those of cortical bone. Slippage increased with decreasing cup-CE angle. A bulk bone graft tightly fixed to the host bone prevented considerably larger slippage between the cup and host bone. A smaller cup-CE angle increased the impact of the bulk bone graft on slippage. When the cup-CE angle was 0° or -10°, the criterion for slippage in favorable initial fixation in all conditions was <40 μm. Even if transplanted bulk bone is used, unless good fixation is obtained between the host bone, and the cup and bone graft, it is impossible to obtain reliable fixation of the cup with a cup-CE angle <-10° and slippage exceeding 40 μm. Bulk bone grafting tightly fixed to the host bone improves initial the cup-host bone fixation, especially when the cup-CE angle is small, such as <-10°. In clinical practice, negative factors are implicated in the initial fixation of various cups, and sufficient fixation between the host bone and cup or bulk bone graft using a screw is effective when the cup-CE angle is extremely small.

Clinical and radiological outcomes with the Durom™ acetabular cup for large-diameter total hip arthroplasty: 177 implants after a mean of 80 months.

PubMed

Saragaglia, D; Belvisi, B; Rubens-Duval, B; Pailhé, R; Rouchy, R C; Mader, R

2015-06-01

Large-diameter metal-on-metal hip prostheses are no longer used, but their outcomes after more than 5 years are unknown. We conducted a retrospective study with a 6.8-year mean follow-up to assess clinical outcomes after Durom™ cup implantation, including the dislocation rate, comparatively to the reference metal-on-polyethylene bearing. We determined the rate of failure ascribable to Durom™ cup use. We also looked for a sharp drop in the implant survival curve during the follow-up period and for factors associated with adverse reactions to metal debris (ARMDs). We hypothesised that clinical outcomes after Durom™ cup implantation were similar to those seen with a metal-on-polyethylene bearing, except for a lower rate of dislocation. We included 177 consecutive THA procedures that were performed between 2005 and 2008 in 165 patients with a mean age of 57.6 ± 9.4 years (range, 31-76 years) and involved the implantation of a Durom™ cup, a femoral head greater than 36mm in diameter, and a PF(®) femoral stem (Zimmer, Etupes, France). The mini-posterior approach was used, with 2mm of acetabular overreaming in 82% of cases, a short femoral neck in 75% of cases, and a mean cup inclination of 34 ± 5° (range, 21-50°). Outcomes were assessed for 156 THA procedures in 146 patients after a mean follow-up of 6 years 8 months. The mean Postel-Merle d'Aubigné score improved from 9.7 ± 2.7 (range, 4-14) to 17.4 ± 1.7 (range, 15-18) and the mean Harris hip score from 45.2 ± 15.3 (range, 9-83) to 96.3 ± 7 (75-100). No episodes of dislocation were recorded. We identified 7 failures ascribable to the Durom™ cup including 6 due to ARMD and 1 to aseptic loosening. Implant survival after a mean of 80months was 95.5% (95% CI, 93.1-99.2), with no sharp drop in the survival curve. The Durom™ cup eliminates the risk of hip dislocation and produces similar functional outcomes to those seen with metal-on-polyethylene bearings after a mean follow-up of 80 months. Nevertheless, given the difficulty in predicting ARMD and hypersensitivity reactions, the Durom™ cup has been discarded and patients carrying it are monitored closely. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Tribology and wear of metal-on-metal hip prostheses: influence of cup angle and head position.

PubMed

Williams, Sophie; Leslie, Ian; Isaac, Graham; Jin, Zhongmin; Ingham, Eileen; Fisher, John

2008-08-01

Clinical studies have indicated that the angular position of the acetabular cup may influence wear in metal-on-metal total hip bearings. A high cup angle in comparison to the anatomical position may lead to the head being constrained by the superior lateral surface and rim of the cup, thus potentially changing the location of the contact zone between the head and the cup. The aim of this study was to test the hypothesis that both a steep cup angle and a lateralized position of the head can increase head contact on the superior rim of the cup, with the consequence of increased wear. Hip-joint simulator studies of metal-on-metal bearings were undertaken with cup angles of 45 degrees and 55 degrees . The femoral head was either aligned to the center of the cup or placed in a position of microlateralization. Wear was measured gravimetrically over 5 million cycles. A steep cup angle of 55 degrees showed significantly higher long-term steady-state wear than a standard cup angle of 45 degrees (p < 0.01). The difference was fivefold. Microlateralization of the head resulted in a fivefold increase in steady-state wear compared with a centralized head. The combination of a steep cup angle and a microlateralized head increased the steady-state wear rate by tenfold compared with a standard cup angle with a centralized head. These studies support the hypothesis that both an increased cup angle and a lateral head position increase wear in metal-on-metal hip prostheses.

Corrosion behaviour and mechanical properties of functionally gradient materials developed for possible hard-tissue applications.

PubMed

Becker, B S; Bolton, J D

1997-12-01

Artificial hip joints have an average lifetime of 10 years due to aseptic loosening of the femoral stem attributed to polymeric wear debris; however, there is a steadily increasing demand from younger osteoarthritis patients aged between 15 and 40 year for a longer lasting joint of 25 years or more. Compliant layers incorporated into the acetabular cup generate elastohydrodynamic lubrication conditions between the bearing surfaces, reduce joint friction coefficients and wear debris production and could increase the average life of total hip replacements, and other human load-bearing joint replacements, i.e. total knee replacements. Poor adhesion between a fully dense substrate and the compliant layer has so far prevented any further exploitation. This work investigated the possibility of producing porous metallic, functionally gradient type acetabular cups using powder metallurgy techniques - where a porous surface was supported by a denser core - into which the compliant layers could be incorporated. The corrosion behaviour and mechanical properties of three biomedically approved alloys containing two levels of total porosity (>30% and <10%) were established, resulting in Ti-6Al-4V being identified as the most promising biocompatible functionally graded material, not only for this application but for other hard-tissue implants.

Possible Vascular Injury Due to Screw Eccentricity in Minimally Invasive Total Hip Arthroplasty.

PubMed

Singh, Nishant Kumar; Rai, Sanjay Kumar; Rastogi, Amit

2017-01-01

Vascular injury during minimally invasive total hip arthroplasty (THA) is uncommon, yet a well-recognized and serious issue. It emerges because of non-visibility of vascular structures proximal to the pelvic bone during reaming, drilling holes, and fixing of screws. Numerous studies have found that screw fixation during cementless THA is beneficial for the initial stability of cup; yet, no anatomical guidelines support angular eccentric screw fixation. In this study, we obtained the pelvic arterial-phase computed tomographic data of thirty eight humans and reconstructed the three-dimensional models of osseous and vessel structures. We performed the surgical simulation to fix these structures with cementless cups and screws with angular eccentricities. The effect of screw eccentricities (angular eccentricities of ±17° and ±34°) on the vascular injury was determined. Measurement between screw and adjoining vessels was performed and analyzed statistically to ascertain a comparative risk study for blood vessels that are not visible during surgery. Authors similarly discussed the significant absence of appreciation of quadrant systems proposed by Wasielewski et al . on eccentric screws. Adjustment of quadrant systems provided by Wasielewski et al . is required for acetabular implants with eccentric holes for fixation of acetabular screws.

Outcome after cementless total hip arthroplasty for arthritic hip in patients with residual poliomyelitis: a case series.

PubMed

Cho, Yoon J; Lee, Choong H; Chun, Young S; Rhyu, Kee H

2016-09-29

In this case series, we investigated the outcome of cementless total hip arthroplasty (THA) for advanced hip osteoarthritis in patients with residual poliomyelitis to evaluate its clinical usefulness for these patients. 11 unilateral cementless primary THA were performed to arthritic hips in patients with residual poliomyelitis. 7 were in paralytic and 4 were in nonparalytic limbs. The mean follow-up duration was 79.9 months. Retrospective clinical evaluations with various scores and radiological evaluations were made. Harris Hip Score, Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Short-form (SF)-36 physical scales were significantly improved after the surgery. However, UCLA activity score and SF-36 mental scale were not. Because of remaining leg length discrepancies, all but 1 noted a residual limp. In nonparalytic hip, functional acetabular cup inclination during weight bearing significantly increased from installed inclination. Other than 1 case of posterior dislocation, no complications were observed. Although the overall result itself is excellent, THA for these patients cannot improve limp, physical activity and mental status. Surgeons should be aware of the change of the inclination of acetabular cup during mobilisation, especially for THA in contralateral hip.

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

Stability of the Giliberty bipolar hip: report of three cases.

PubMed

Langan, P; Weiss, C A

1978-01-01

The Giliberty Bipolar Hip Prosthesis consists of an unbonded acetabular cup which snap-fits over the head of the femoral prosthesis. Because of the free movement permitted at the cup-pelvic junction as well as at the snap-fit interface, there has been a great deal of concern over the potential for dislocation. Three patients in whom this unit was implanted sustained significant skeletal trauma subsequent to surgery. None of them dislocated. In each case the prosthetic head was known to be in a relatively vertical orientation with respect to the transverse axis of the pelvis prior to the injury. In 2 of the 3 cases radiographically identifiable movement of the cup was present before and after the injury. These observations suggest that the persistently mobile, vertically positioned unbonded cup remain stable despite the stress of significant trauma. It is probable that the potential for cup movement, even where on the X-ray it appears to have stopped, acts as a safety valve in absorbing force that might otherwise dislocate the hip or cause fractures of the femur or the pelvis.

Bone preserving techniques for explanting the well-fixed cemented acetabular component.

PubMed

Stevens, Jarrad; Macpherson, Gavin; Howie, Colin

2018-06-01

Removal of a well-fixed, cemented acetabular component at the time of revision hip surgery can be complex. It is essential to remove the implant and cement mantle in a timely fashion while preserving bone stock and osseous integrity. The biomechanical properties of polymethylmethacrylate cement and polyethylene can be utilised to aid with the removal of well cemented implants which are often harder than the surrounding bone. While removal of loose components may be relatively straightforward, the challenge for the revision arthroplasty surgeon often involves the removal of well-fixed implants. Here, we present three established techniques for the removal of a well-fixed cemented acetabular component and one novel modification we have described before. We collate and review four techniques for removing well-fixed cemented acetabular implants that utilise the different biomechanical properties of bone cement and polyethylene. These techniques are illustrated with a photographic series utilising saw bones. A step-by-step approach to our new technique is shown in photographs, both in the clinical setting and with a "Sawbone". This is accompanied by a clinical video that details the surgical technique in its entirety. These techniques utilise different biomechanical principles to extract the acetabular component. Each technique has advantages and disadvantages. Our new technique is a simplification of a previously published extraction manoeuvre that utilises tensile force between cement and the implant to remove the polyethylene cup. This is a safe and reproducible technique in patients with a well-fixed cemented acetabular implant. Understanding the biomechanical properties of polymethylmethacrylate bone cement and polyethylene can aid in the safe removal of a well-fixed cemented acetabular component in revision hip surgery. The optimal technique for removal of a cemented acetabular component varies depending on a number of patient and implant factors. This summary of the available techniques will be of interest to revision arthroplasty surgeons.

75 FR 2483 - Certain Steel Nails from the People's Republic of China: Notice of Preliminary Results of the New...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-15

... or more times), phosphate cement, and paint. Head styles include, but are not limited to, flat, projection, cupped, oval, brad, headless, double, countersunk, and sinker. Shank styles include, but are not limited to, smooth, barbed, screw threaded, ring shank and fluted shank styles. Screw-threaded nails...

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.

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.

Wear characteristics of UHMW polyethylene by twist method

NASA Astrophysics Data System (ADS)

Chișiu, G.; Popescu, A. M.; Tudor, A.; Petrescu, A. M.; Stoica, G. F.; Subhi, K. A.

2018-01-01

A wear test of the twist movement was performed as a new method to estimate the in vivo wear behavior of an acetabular cup material for total knee replacements. A series of UHMWPE samples was used to evaluate the dynamic coefficient of friction in twist movement in contact with steel. The experimental data were conducted to validate the related theoretical model developed in the present study.

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.

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.

In vivo and ex vivo measurement of polyethylene wear in total hip arthroplasty: comparison of measurements using a CT algorithm, a coordinate-measuring machine, and a micrometer.

PubMed

Goldvasser, Dov; Hansen, Viktor J; Noz, Marilyn E; Maguire, Gerald Q; Zeleznik, Michael P; Olivecrona, Henrik; Bragdon, Charles R; Weidenhielm, Lars; Malchau, Henrik

2014-06-01

Determination of the amount of wear in a polyethylene liner following total hip arthroplasty (THA) is important for both the clinical care of individual patients and the development of new types of liners. We measured in vivo wear of the polyethylene liner using computed tomography (CT) (obtained in the course of regular clinical care) and compared it to coordinate-measuring machine (CMM) readings. Also, changes in liner thickness of the same retrieved polyethylene liner were measured using a micrometer, and were compared to CT and CMM measurements. The distance between the centers of the acetabular cup and femoral head component was measured in 3D CT, using a semi-automatic analysis method. CMM readings were performed on each acetabular liner and data were analyzed using 3D computer-aided design software. Micrometer readings compared the thickest and thinnest regions of the liner. We analyzed 10 THA CTs and retrievals that met minimal requirements for CT slice thickness and explanted cup condition. RESULTS - For the 10 cups, the mean difference between the CT readings and the CMM readings was -0.09 (-0.38 to 0.20) mm. This difference was not statistically significant (p = 0.6). Between CT and micrometer, the mean difference was 0.11 (-0.33 to 0.55) mm. This difference was not statistically significant (p = 0.6). INTERPRETATION - Our results show that CT imaging is ready to be used as a tool in clinical wear measurement of polyethylene liners used in THA.

Possible Vascular Injury Due to Screw Eccentricity in Minimally Invasive Total Hip Arthroplasty

PubMed Central

Singh, Nishant Kumar; Rai, Sanjay Kumar; Rastogi, Amit

2017-01-01

Background: Vascular injury during minimally invasive total hip arthroplasty (THA) is uncommon, yet a well-recognized and serious issue. It emerges because of non-visibility of vascular structures proximal to the pelvic bone during reaming, drilling holes, and fixing of screws. Numerous studies have found that screw fixation during cementless THA is beneficial for the initial stability of cup; yet, no anatomical guidelines support angular eccentric screw fixation. Materials and Methods: In this study, we obtained the pelvic arterial-phase computed tomographic data of thirty eight humans and reconstructed the three-dimensional models of osseous and vessel structures. We performed the surgical simulation to fix these structures with cementless cups and screws with angular eccentricities. Results: The effect of screw eccentricities (angular eccentricities of ±17° and ±34°) on the vascular injury was determined. Measurement between screw and adjoining vessels was performed and analyzed statistically to ascertain a comparative risk study for blood vessels that are not visible during surgery. Conclusion: Authors similarly discussed the significant absence of appreciation of quadrant systems proposed by Wasielewski et al. on eccentric screws. Adjustment of quadrant systems provided by Wasielewski et al. is required for acetabular implants with eccentric holes for fixation of acetabular screws. PMID:28790474

Three-dimensional orientation and location-dependent varying rules of radiographic angles of the acetabular cup.

PubMed

Zhao, Jing-Xin; Su, Xiu-Yun; Zhao, Zhe; Xiao, Ruo-Xiu; Zhang, Li-Cheng; Tang, Pei-Fu

2018-02-17

The aim of this study is to demonstrate the varying rules of radiographic angles following varying three-dimensional (3D) orientations and locations of cup using an accurate mathematical model. A cone model is established to address the quantitative relationship between the opening circle of cup and its ellipse projection on radiograph. The varying rules of two-dimensional (2D) radiographic anteversion (RA) and inclination (RI) angles can be analyzed. When the centre of cup is located above X-ray source, with proper 3D RI/RA angles, 2D RA angle can be equal to its 3D counterpart, and 2D RI angle is usually greater than its 3D counterpart. Except for the original point on hip-centered anterior-posterior radiograph, there is no area on radiograph where both 2D RA and RI angles are equal to their 3D counterparts simultaneously. This study proposes an innovative model for accurately explaining how 2D RA/RI angles of cup are varying following different 3D RA/RI angles and location of cup. The analysis results provide clinicians an intuitive grasp of knowledge about 2D RA/RI angles greater or smaller than their 3D counterparts post-operatively. The established model may allow determining the effects of pelvic rotations on 2D radiographic angles of cup.

[Acetabular Osteolysis in Total Hip Replacement - When to Retain the Cup?].

PubMed

Lutz, B; Faschingbauer, M; Bieger, R; Reichel, H; Kappe, T

2016-08-01

Periacetabular osteolysis is a frequent long-term complication of cementless total hip arthroplasty. The decision whether to retain or to revise a cup in the presence of osteolysis remains a challenge. The options are regular clinical and radiological check-ups, isolated liner exchange with and without bone grafting, and complete cup revision. Thorough preoperative diagnostics, including a medical history, examination and imaging, are mandatory for correct decision making. In most patients, computed tomography is useful to assess periacetabular osteolysis. If the cup is well-fixed and positioned in an asymptomatic patient without progressive osteolysis and no implant defect or higher grade polyethylene wear and no signs of infection, continuous clinical and radiological monitoring is preferred. If imaging reveals cup loosening, malposition, osteolysis localised in a weight-bearing area, imminent or present periprosthetic fractures, rapid progressive osteolysis, implant defects or massive inlay wear, surgical treatment may be preferred. Cup revision is usually performed in such patients. If the cup is well-positioned and well-fixed in the X-ray, the procedure has to be discussed with the patient individually. Apart from patient-specific risk factors, the risk of further progression has to be assessed. Isolated liner exchange can be performed if the patient is asymptomatic and the cup proves to be stable intraoperatively. It is still unclear whether filling osteolyses through screw holes or osseous windows is of long-term benefit. Georg Thieme Verlag KG Stuttgart · New York.

Dermatoses secondary to Asian cultural practices.

PubMed

Lilly, Evelyn; Kundu, Roopal V

2012-04-01

Although Asian cultural practices, such as acupuncture and threading, are widely used, there is limited medical literature describing their cutaneous effects and complications. This review briefly describes therapeutic cultural practices (traditional Chinese medicine, acupuncture, cupping, moxibustion, coining, Ayurveda, and aromatherapy) and cosmetic cultural practices (hair oils, henna, bindis, saris, and threading), with particular attention to dermatoses secondary to these practices. Traditional Chinese medicine and Ayurveda may cause heavy metal toxicity, severe cutaneous adverse reactions, and contact dermatitis. Cupping, moxibustion, and coining lead to dermatoses that may be mistaken for abuse by people unfamiliar with the practices. Hair oils may cause contact dermatitis and folliculitis. Paraphenylenediamine in black henna and bindi dyes and adhesives can cause severe allergic contact dermatitis. The drawstring in saris causes frictional irritation, which can lead to tinea corporis, koebnerization, and even squamous cell carcinoma. Threading may cause folliculitis, impetigo, and verrucae. The increasing prevalence of Asian cultural practices, which are performed inside and outside of Asia in this era of globalization, demands that dermatologists be familiar with the secondary dermatoses that may develop. © 2012 The International Society of Dermatology.

Does cyclic stress and accelerated ageing influence the wear behavior of highly crosslinked polyethylene?

PubMed

Affatato, Saverio; De Mattia, Jonathan Salvatore; Bracco, Pierangiola; Pavoni, Eleonora; Taddei, Paola

2016-06-01

First-generation (irradiated and remelted or annealed) and second-generation (irradiated and vitamin E blended or doped) highly crosslinked polyethylenes were introduced in the last decade to solve the problems of wear and osteolysis. In this study, the influence of the Vitamin-E addition on crosslinked polyethylene (XLPE_VE) was evaluated by comparing the in vitro wear behavior of crosslinked polyethylene (XLPE) versus Vitamin-E blended polyethylene XLPE and conventional ultra-high molecular weight polyethylene (STD_PE) acetabular cups, after accelerated ageing according to ASTM F2003-02 (70.0±0.1°C, pure oxygen at 5bar for 14 days). The test was performed using a hip joint simulator run for two millions cycles, under bovine calf serum as lubricant. Mass loss was found to decrease along the series XLPE_VE>STD_PE>XLPE, although no statistically significant differences were found between the mass losses of the three sets of cups. Micro-Raman spectroscopy was used to investigate at a molecular level the morphology changes induced by wear. The spectroscopic analyses showed that the accelerated ageing determined different wear mechanisms and molecular rearrangements during testing with regards to the changes in both the chain orientation and the distribution of the all-trans sequences within the orthorhombic, amorphous and third phases. The results of the present study showed that the addition of vitamin E was not effective to improve the gravimetric wear of PE after accelerated ageing. However, from a molecular point of view, the XLPE_VE acetabular cups tested after accelerated ageing appeared definitely less damaged than the STD_PE ones and comparable to XLPE samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

A novel approach to determine primary stability of acetabular press-fit cups.

PubMed

Weißmann, Volker; Boss, Christian; Bader, Rainer; Hansmann, Harald

2018-04-01

Today hip cups are used in a large variety of design variants and in increasing numbers of units. Their development is steadily progressing. In addition to conventional manufacturing methods for hip cups, additive methods, in particular, play an increasingly important role as development progresses. The present paper describes a modified cup model developed based on a commercially available press-fit cup (Allofit 54/JJ). The press-fit cup was designed in two variants and manufactured using selective laser melting (SLM). Variant 1 (Ti) was modeled on the Allofit cup using an adapted process technology. Variant 2 (Ti-S) was provided with a porous load bearing structure on its surface. In addition to the typical (complete) geometry, both variants were also manufactured and tested in a reduced shape where only the press-fit area was formed. To assess the primary stability of the press-fit cups in the artificial bone cavity, pull-out and lever-out tests were carried out. Exact fit conditions and two-millimeter press-fit were investigated. The closed-cell PU foam used as an artificial bone cavity was mechanically characterized to exclude any influence on the results of the investigation. The pull-out forces of the Ti-variant (complete-526 N, reduced-468 N) and the Ti-S variant (complete-548 N, reduced-526 N) as well as the lever-out moments of the Ti-variant (complete-10 Nm, reduced-9.8 Nm) and the Ti-S variant (complete-9 Nm, reduced-7.9 N) show no significant differences in the results between complete and reduced cups. The results show that the use of reduced cups in a press-fit design is possible within the scope of development work. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bone remodelling around HA-coated acetabular cups

PubMed Central

Nielsen, P. T.; Søballe, K.

2006-01-01

This study was designed to investigate bone remodelling around the cup in cementless THA. Previous studies indicate an advantage of better sealing of the bone-prosthesis interface by HA/TCP coating of implants, inhibiting polyethylene-induced osteolysis. One hundred patients gave informed consent to participate in a controlled randomized study between porous coated Trilogy versus Trilogy Calcicoat (HA/TCP coated). The cup was inserted in press-fit fixation. The femoral component was a cementless porous coated titanium alloy stem (Bi-Metric), with a modular 28-mm CrCo head. The Harris Hip Score (HHS) and bone mineral density (BMD) determined by DEXA scanning were used to study the effect. Measurements revealed no difference between the two groups after 3 years either in the clinical outcome or in terms of periprosthetic bone density. Patients with a body mass index above normal regained more bone mineral than patients with normal weight. This finding supports the assumption that load is beneficial to bone remodelling. PMID:16761153

Three Year RSA Evaluation of Vitamin E Diffused Highly Cross-linked Polyethylene Liners and Cup Stability.

PubMed

Sillesen, Nanna H; Greene, Meridith E; Nebergall, Audrey K; Nielsen, Poul T; Laursen, Mogens B; Troelsen, Anders; Malchau, Henrik

2015-07-01

Vitamin E diffusion into highly cross-linked polyethylene (E-XLPE) is a method for enhancing oxidative stability of acetabular liners. The purpose of this study was to evaluate in vivo penetration of E-XLPE using radiostereometric analysis (RSA). Eighty-four hips were recruited into a prospective 10-year RSA. This is the first evaluation of the multicenter cohort after 3-years. All patients received E-XLPE liners (E1, Biomet) and porous-titanium coated cups (Regenerex, Biomet). There was no difference (P=0.450) in median femoral head penetration into the E-XLPE liners at 3-years comparing cobalt-chrome heads (-0.028mm; inter-quartile range (IQR) - 0.065 to 0.047) with ceramic heads (-0.043mm, IQR - 0.143to0.042). The 3-year follow-up indicates minimal E-XLPE liner penetration regardless of head material and minimal early cup movement. Copyright © 2015 Elsevier Inc. All rights reserved.

Alignment Pins for Assembling and Disassembling Structures

NASA Technical Reports Server (NTRS)

Campbell, Oliver C.

2008-01-01

Simple, easy-to-use, highly effective tooling has been devised for maintaining alignment of bolt holes in mating structures during assembly and disassembly of the structures. The tooling was originally used during removal of a body flap from the space shuttle Atlantis, in which misalignments during removal of the last few bolts could cause the bolts to bind in their holes. By suitably modifying the dimensions of the tooling components, the basic design of the tooling can readily be adapted to other structures that must be maintained in alignment. The tooling includes tapered, internally threaded alignment pins designed to fit in the bolt holes in one of the mating structures, plus a draw bolt and a cup that are used to install or remove each alignment pin. In preparation for disassembly of two mating structures, external supports are provided to prevent unintended movement of the structures. During disassembly of the structures, as each bolt that joins the structures is removed, an alignment pin is installed in its place. Once all the bolts have been removed and replaced with pins, the pins maintain alignment as the structures are gently pushed or pulled apart on the supports. In assembling the two structures, one reverses the procedure described above: pins are installed in the bolt holes, the structures are pulled or pushed together on the supports, then the pins are removed and replaced with bolts. The figure depicts the tooling and its use. To install an alignment pin in a bolt hole in a structural panel, the tapered end of the pin is inserted from one side of the panel, the cup is placed over the pin on the opposite side of the panel, the draw bolt is inserted through the cup and threaded into the pin, the draw bolt is tightened to pull the pin until the pin is seated firmly in the hole, then the draw bolt and cup are removed, leaving the pin in place. To remove an alignment pin, the cup is placed over the pin on the first-mentioned side of the panel, the draw bolt is inserted through the cup and threaded into the pin, then the draw bolt is tightened to pull the pin out of the hole.

Fracture of Ceramic Liner and Head in a Total Hip Arthroplasty with a Sandwich Type Cup

PubMed Central

Reátegui, Diego; García, Sebastián; Bori, Guillem; Gallart, Xavier

2013-01-01

Due to its advantages, ceramic-on-ceramic bearings have been widely used in young patients for almost 30 years. Long-term survivorship, low wear, and low biological reactivity to particles are some of its characteristics. Even though this material has had a lot of improvements, the risk of fracture is one of the concerns. There have been reports of fracture of ceramic in the acetabular liner and head but no fractures of both in the same patient. We report a case of a fracture in a sandwich type acetabular liner and the ceramic head in a patient involving ankylosing spondylitis. It occurred three years after the operation and with no history of direct trauma. We decided to change the bearing surfaces to metal polyethylene without removing the metal back. The patient is satisfied by the clinical results after a 5-year followup. PMID:23691392

All dual mobility cups are not the same.

PubMed

Aslanian, Thierry

2017-03-01

Although the natural history of dual mobility has been exclusively borne for 20 years by a single company (due to industrial ownership), the concept has undeniably been very widely popularised with nearly 40 cups on the French market which should be regarded as a weight bearing surface, both broadly and in their own right. However, within the same original idea, these implants are not all identical (design, material, fixation ect.).The aim of this work is to propose a classification of different dual mobility cups by distinguishing between thegeneral characteristics of a conventional cup and those particular to this type of implant. By comparison with a standard metal-back cup, dual mobility is based on at least one additional interface corresponding to the mobility of the polyethylene insert in the concavity of the acetabular cup called the outersurface. Design, constitutive material, fixation of the cup and characteristics of the retentive insert are analysed through the published results. The complications associated, in particular, the intraprosthetic dislocation and to a lesser extent fixation failures undoubtedly condemned the dissemination of the dual mobility concept, as witnessed by the fact that despite the precedence of this 40-year old concept, the overriding majority of publications (more than 95%) have only appeared in the last ten years. The latest generation of dual mobility cups combines: 1) a cast chrome-cobalt alloy cup covered with a bilayer coating of porous titanium and hydroxyapatite for long-term press-fit fixation to 2) an insert designed to eliminate all of the risks of intraprosthetic dislocation, whilst keeping all of the elasticity properties of the polyethylene, which has demonstrated its medium and long term effectiveness on preventing instability by overcoming other complications.

"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.

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.

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.

Outcomes of cup revision for ilio-psoas impingement after total hip arthroplasty: Retrospective study of 46 patients.

PubMed

Batailler, C; Bonin, N; M Wettstein; Nogier, A; Martres, S; Ollier, E; May, O; Lustig, S

2017-12-01

Impingement of the ilio-psoas tendon on the acetabular component is a cause of pain after total hip arthroplasty (THA). Studies of cup revision for ilio-psoas impingement (IPI) are scarce and limited in size. We therefore conducted a large multicentre retrospective study with the following objectives: to assess the effectiveness of cup replacement in resolving the impingement syndrome, to determine the frequency and nature of complications after cup revision for IPI, and to identify pre-operative factors associated with good outcomes of cup revision for IPI. Cup revision is effective in resolving the pain due to IPI in selected patients. This retrospective multicentre study included 46 patients who underwent cup revision because of IPI. Before the revision, 38 (83%) patients had prominence of the anterior cup rim (mean, 9.9±4.5mm (range, 2-22mm) by radiography and 35 (76%) had cup malposition (anteversion<10° and/or inclination>50°). Mean follow-up was 21months (range, 6months to 6 years) and no patient was lost to follow-up. Outcomes at last follow-up were assessed based on the Oxford Hip Score (OHS), patient satisfaction index, complications, and revisions. At last follow-up, 39 (85%) patients were satisfied with the revision procedure, a significant improvement versus baseline was noted in the OHS (mean, 43±6; range, 25-48; P<0.001), and 41 patients were free of pain during hip flexion (P<0.001 versus baseline). Complications occurred in 3 (6.5%) patients, but only one complication was severe (deep infection). Recurrent groin pain was reported by 4 (8.7%) patients at last follow-up. None of the factors studied predicted the outcome of revision surgery. Cup revision for IPI after THA is effective in relieving the groin pain in 80% of patients with anterior cup rim prominence and/or cup malposition. However, complications can occur. Tenotomy may be preferable when the diagnosis is in doubt and/or cup position is acceptable. IV, retrospective observational study. Published by Elsevier Masson SAS.

Efficacy of a Pelvic Lateral Positioner With a Mechanical Cup Navigator Based on the Anatomical Pelvic Plane in Total Hip Arthroplasty.

PubMed

Iwakiri, Kentaro; Kobayashi, Akio; Ohta, Yoichi; Minoda, Yukihide; Takaoka, Kunio; Nakamura, Hiroaki

2017-12-01

The acetabular component orientation in total hip arthroplasty (THA) is of critical importance to the good clinical results. However, traditional widely used cup alignment guides for cup placement are reported to be relatively unreliable. The present study aims at comparing a novel cup alignment guide, which can be attached to our anatomical pelvic plane (APP) pelvic lateral positioner for reducing discrepancies in sagittal pelvic tilt and indicate a targeted cup angle based on the APP, with a conventional cup alignment guide. The subjects were 136 hips of 136 patients who underwent unilateral THA using the APP positioner. The procedure was performed with the conventional cup alignment guide (conventional group; 60 hips) and with the novel cup navigator (mechanical navigator group; 76 hips). Postoperative cup angles and discrepancies of postoperative cup angles (inclination and anteversion angles) from the targeted angles were compared between the 2 groups to evaluate the usefulness of these navigators. The mean cup angles in the conventional group were 39.0° ± 5.3° for the inclination angle and 21.7° ± 6.4° for the anteversion angle, whereas those in the mechanical navigator group were 40.6° ± 3.2° and 18.3° ± 4.6°, respectively (P = .018, P < .0001). The discrepancies from the targeted angles were 3.5° ± 3.1° for the inclination angle and 4.6° ± 3.4° for the anteversion angle in the conventional group and 2.3° ± 2.3° and 3.2° ± 2.7°, respectively, in the mechanical navigator group (P = .020, P = .012). The mechanical cup navigator easily attachable to the APP positioner is a tool that can improve the accuracy of cup placement in a simple, economical, and noninvasive manner in THA via the lateral position. Copyright © 2017 Elsevier Inc. All rights reserved.

Selection of contact bearing couple materials for hip prosthesis using finite element analysis under static conditions

NASA Astrophysics Data System (ADS)

Arirajan, K. A.; Chockalingam, K.; Vignesh, C.

2018-04-01

Implants are the artificial parts to replace the missing bones or joints in human anatomy to give mechanical support. Hip joint replacement is an important issue in orthopaedic surgery. The main concern limiting the long-run success of the total hip replacement is the limited service life. Hip replacement technique is widely used in replacing the femur head and acetabular cup by materials that are highly biocompatible. The success of the artificial hip replacement depends upon proper material selection, structure, and shape of the hip prosthesis. Many orthopaedic analyses have been tried with different materials, but ended with partial success on the application side. It is a critical task for selecting the best material pair in the hip prosthesis design. This work develops the finite element analysis of an artificial hip implant to study highest von Mises stress, contact pressure and elastic strain occurs for the dissimilar material combination. The different bearing couple considered for the analysis are Metal on Metal, Metal on Plastic, Metal on Ceramic, Ceramic on Plastic, Ceramic on Ceramic combinations. The analysis is carried out at different static positions of a human (i.e) standing, sitting. The results reveals that the combination with metal in contact with plastic (i.e) Titanium femoral head paired with Ultra High Molecular Weight Poly Ethylene acetabular cup reduces maximum von Mises stress and also it gives lowest contact pressure than other combination of bearing couples.

Risk factors for accelerated polyethylene wear and osteolysis in ABG I total hip arthroplasty

PubMed Central

Havranek, Vitezslav; Zapletalova, Jana

2009-01-01

We analysed data from 155 revisions of identical cementless hip prostheses to determine the influence of patient-, implant- and surgery-related factors on the polyethylene wear rate and size of periprosthetic osteolysis (OL). This was calculated by logistic regression analysis. Factors associated with an increased/decreased wear rate included position of the cup relative to Kohler’s line, increase in abduction angle of the cup, traumatic and inflammatory arthritis as a primary diagnosis, and patient height. Severe acetabular bone defects were predicted by an increased wear rate (odds ratio, OR = 5.782 for wear rate above 200 mm3/y), and increased height of the patient (OR = 0.905 per each centimetre). Predictors of severe bone defects in the femur were the increased wear rate (OR = 3.479 for wear rate above 200 mm3/y) and placement of the cup outside of the true acetabulum (OR = 3.292). Variables related to surgical technique were the most predictive of polyethylene wear rate. PMID:19214506

[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.

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.

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.

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.

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.

Equally good fixation of cemented and uncemented cups in total trapeziometacarpal joint prostheses. A randomized clinical RSA study with 2-year follow-up.

PubMed

Hansen, Torben Baek; Stilling, Maiken

2013-02-01

Cup failure is a recognized problem in total trapeziometacarpal (TM) joint prostheses; it may be related to poor fixation, which can be revealed by radiostereometric analysis (RSA). We compared the early implant migration of cemented trapezium cups to that of uncemented screw cups. In a prospective, parallel-group, randomized patient-blinded clinical trial, we included 32 hands in 28 patients (5 males) with a mean age of 58 (40-77) years and with Eaton stage-2 or -3 osteoarthritis of the trapeziometacarpal joint. Patients were randomized to surgery with a cemented DLC all-polyethylene cup (C) (n = 16) or an uncemented hydroxyapatite-coated chrome-cobalt Elektra screw cup (UC) (n = 16). Uncemented cups were inserted without threading of the bone. Stereoradiographs for evaluation of cup migration (primary effect size) and DASH and pain scores were obtained during 2 years of follow-up. The 2-year total translation (TT) was similar (p = 0.2): 0.24 mm (SD 0.10) for the C (n = 11) and 0.19 mm (SD 0.16) for the UC (n = 11). Variances were similar (p = 0.4). Judged by RSA, 2 UC cups and 1 C cup became loose (TT > 1 mm). Both UC cups were found to be loose at revision. Grip strength, pain, and DASH scores were similar between groups at all measurement points. Early implant fixation and clinical outcome were equally good with both cup designs. This is the first clinical RSA study on trapezium cups, and the method appears to be clinically useful for detection of loose implants.

Effects of implant design parameters on fluid convection, potentiating third-body debris ingress into the bearing surface during THA impingement/subluxation.

PubMed

Lundberg, Hannah J; Pedersen, Douglas R; Baer, Thomas E; Muste, Marian; Callaghan, John J; Brown, Thomas D

2007-01-01

Aseptic loosening from polyethylene wear debris is the leading cause of failure for metal-on-polyethylene total hip implants. Third-body debris ingress to the bearing space results in femoral head roughening and acceleration of polyethylene wear. How third-body particles manage to enter the bearing space between the closely conforming articulating surfaces of the joint is not well understood. We hypothesize that one such mechanism is from convective fluid transport during subluxation of the total hip joint. To test this hypothesis, a three-dimensional (3D) computational fluid dynamics (CFD) model was developed and validated, to quantify fluid ingress into the bearing space during a leg-cross subluxation event. The results indicated that extra-articular joint fluid could be drawn nearly to the pole of the cup with even very small separations of the femoral head (<0.60mm). Debris suspended near the equator of the cup at the site of maximum fluid velocity just before the subluxation began could be transported to within 11 degrees from the cup pole. Larger head diameters resulted in increased fluid velocity at all sites around the entrance to the gap compared to smaller head sizes, with fluid velocity being greatest along the anterosuperolateral cup edge, for all head sizes. Fluid pathlines indicated that suspended debris would reach similar angular positions in the bearing space regardless of head size. Increased inset of the femoral head into the acetabular cup resulted both in higher fluid velocity and in transport of third-body debris further into the bearing space.

24 CFR 3280.605 - Joints and connections.

Code of Federal Regulations, 2013 CFR

2013-04-01

... of the fitting. Plastic pipe and copper tubing shall be inserted to the full depth of the solder cup..., cutting oil and foreign matter shall be removed. Pipe joint cement or thread lubricant shall be of... connected to a public water system, made with solder having not more than 0.2 percent lead. (4) Plastic pipe...

24 CFR 3280.605 - Joints and connections.

Code of Federal Regulations, 2012 CFR

2012-04-01

... of the fitting. Plastic pipe and copper tubing shall be inserted to the full depth of the solder cup..., cutting oil and foreign matter shall be removed. Pipe joint cement or thread lubricant shall be of... connected to a public water system, made with solder having not more than 0.2 percent lead. (4) Plastic pipe...

Outcomes of dual-mobility acetabular cup for instability in primary and revision total hip arthroplasty.

PubMed

Mohammed, Riazuddin; Hayward, Keith; Mulay, Sanjay; Bindi, Frank; Wallace, Murray

2015-03-01

The concept of a dual-mobility hip socket involves the standard femoral head component encased in a larger polyethylene liner, which in turn articulates inside a metal shell implanted in the native acetabulum. The aim of this study was to assess outcomes from using a Serf Novae(®) Dual Mobility Acetabular cup (Orthodynamics Ltd, Gloucestershire, UK) to address the problem of instability in primary and revision total hip arthroplasty (THA). A retrospective review was carried out of all hip arthroplasties performed in a District General Hospital utilising the dual-mobility socket from January 2007 to December 2012. Clinical and radiological outcomes were analysed for 44 hips in 41 patients, comprising 20 primary and 24 revision THA. The average age of the study group was 70.8 years (range 56-84 years) for primary and 76.4 years (range 56-89 years) for revision arthroplasty. Among the primary THA, always performed for hip osteoarthritis or in presence of osteoarthritic changes, the reasons to choose a dual mobility cup were central nervous system problems such as Parkinson's disease, stroke, dementia (10), hip fracture (5), failed hip fracture fixation (2), severe fixed hip deformity (2) and diffuse peripheral neuropathy (1). The indications for revisions were recurrent dislocation (17), aseptic loosening with abductor deficiency (4), failed hemiarthroplasty with abductor deficiency (2) and neglected dislocation (1). At a mean follow-up of 22 months (range 6-63 months), none of the hips had any dislocation, instability or infection and no further surgical intervention was required. Radiological assessment showed that one uncemented socket in a revision arthroplasty performed for recurrent dislocation had changed position, but was stable in the new position. The patient did not have complications from this and did not need any surgical intervention. Even though postoperative hip stability depends on several factors other than design-related ones, our study shows promising early results for reducing the risk of instability in this challenging group of patients undergoing primary and revision hip arthroplasty. IV.

Nine Year Follow-up of a Ceramic-on-Ceramic Bearing Total Hip Arthroplasty Utilizing a Layered Monoblock Acetabular Component

PubMed Central

Mayor, David; Patel, Savan; Perry, Clayton; Walter, Norman; Burton, Stephen; Atkinson, Theresa

2014-01-01

Introduction Early ceramic bearing systems in total hip arthoplasty (THA) sought to provide long term wear improvement over traditional metal on polyethylene systems. However, previous designs exhibited fractures of the ceramic acetabular liner, leading to the development of the Implex Hedrocel ceramic bearing THA system where the ceramic liner was supported on a layer of polyethylene intended to transition liner loads to the metal shell, a so-called “sandwich” design. Unfortunately, the device trial was stopped to further enrollment when liner fractures were reported. The current study examines nearly 10-year follow-up on 28 devices implanted by two surgeons at one institution in order to document ceramic bearing system performance over a longer time period. Methods Radiographic and patient reported outcomes, in the form of Harris Hip Scores (HHS) and 12-Item Short Form Health Survey (sF-12), were collected. Results During the study period two cups were replaced, one at three years and a second at seven years. At the five year follow-up HHS were similar to those reported in the literature for devices with traditional metal-on-polyethylene bearing surfaces and for other sandwich ceramic bearing designs. At the nine year follow-up, the HHS had not changed significantly and SF-12 scores measuring overall physical and mental health were higher than age matched national norms (p<0.001). There were no signs of cup migration, stem subsidence, osteolysis or cup loosening at any time up to the last follow-up in this patient cohort. The 89% survivorship rate and device revisions due to delamination of the liner observed in this group were similar to those reported earlier for this device and for other “sandwich design” ceramic bearing systems. Discussion This cohort did not exhibit new failure modes and HHS and SF-12 scores indicated high functionality for the majority of patients. These data suggest that a focus on preventing ceramic liner fracture through design and/or materials improvements may result in a device with long-term functionality. PMID:25328464

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

Poor short term outcome with a metal-on-metal total hip arthroplasty.

PubMed

Levy, Yadin D; Ezzet, Kace A

2013-08-01

Metal-on-metal (MoM) bearings for total hip arthroplasty (THA) have come under scrutiny with reports of high failure rates. Clinical outcome studies with several commercially available MoM THA bearings remain unreported. We evaluated 78 consecutive MoM THAs from a single manufacturer in 68 patients. Sixty-six received cobalt-chrome (CoCr) monoblock and 12 received modular titanium acetabular cups with internal CoCr liners. Femoral components were titanium with modular necks. At average 2.1 years postoperatively, 12 THAs (15.4%) demonstrated aseptic failure (10 revisions, 2 revision recommended). All revised hips demonstrated capsular necrosis with positive histology reaction for aseptic lymphocytic vasculitis-associated lesions/adverse local tissue reactions. Prosthetic instability following revision surgery was relatively common. Female gender was a strong risk factor for failure, though smaller cups were not. Both monoblock and modular components fared poorly. Corrosion was frequently observed around the proximal and distal end of the modular femoral necks. Copyright © 2013 Elsevier Inc. All rights reserved.

MALDI-TOF mass spectrometry imaging reveals molecular level changes in ultrahigh molecular weight polyethylene joint implants in correlation with lipid adsorption.

PubMed

Fröhlich, Sophie M; Archodoulaki, Vasiliki-Maria; Allmaier, Günter; Marchetti-Deschmann, Martina

2014-10-07

Ultrahigh molecular weight polyethylene (PE-UHMW), a material with high biocompatibility and excellent mechanical properties, is among the most commonly used materials for acetabular cup replacement in artificial joint systems. It is assumed that the interaction with synovial fluid in the biocompartment leads to significant changes relevant to material failure. In addition to hyaluronic acid, lipids are particularly relevant for lubrication in an articulating process. This study investigates synovial lipid adsorption on two different PE-UHMW materials (GUR-1050 and vitamin E-doped) in an in vitro model system by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry imaging (MSI). Lipids were identified by high performance thin layer chromatography (HP-TLC) and tandem mass spectrometry (MS/MS) analysis, with an analytical focus on phospholipids and cholesterol, both being species of high importance for lubrication. Scanning electron microscopy (SEM) analysis was applied in the study to correlate molecular information with PE-UHMW material qualities. It is demonstrated that lipid adsorption preferentially occurs in rough or oxidized polymer regions. Polymer modifications were colocalized with adsorbed lipids and found with high density in regions identified by SEM. Explanted, the in vivo polymer material showed comparable and even more obvious polymer damage and lipid adsorption when compared with the static in vitro model. A three-dimensional reconstruction of MSI data from consecutive PE-UHMW slices reveals detailed information about the diffusion process of lipids in the acetabular cup and provides, for the first time, a promising starting point for future studies correlating molecular information with commonly used techniques for material analysis (e.g., Fourier-transform infrared spectroscopy, nanoindentation).

Confocal Raman spectroscopic analysis of cross-linked ultra-high molecular weight polyethylene for application in artificial hip joints.

PubMed

Pezzotti, Giuseppe; Kumakura, Tsuyoshi; Yamada, Kiyotaka; Tateiwa, Toshiyuki; Puppulin, Leonardo; Zhu, Wenliang; Yamamoto, Kengo

2007-01-01

Confocal spectroscopic techniques are applied to selected Raman bands to study the microscopic features of acetabular cups made of ultra-high molecular weight polyethylene (UHMWPE) before and after implantation in vivo. The micrometric lateral resolution of a laser beam focused on the polymeric surface (or subsurface) enables a highly resolved visualization of 2-D conformational population patterns, including crystalline, amorphous, orthorhombic phase fractions, and oxidation index. An optimized confocal probe configuration, aided by a computational deconvolution of the optical probe, allows minimization of the probe size along the in-depth direction and a nondestructive evaluation of microstructural properties along the material subsurface. Computational deconvolution is also attempted, based on an experimental assessment of the probe response function of the polyethylene Raman spectrum, according to a defocusing technique. A statistical set of high-resolution microstructural data are collected on a fully 3-D level on gamma-ray irradiated UHMWPE acetabular cups both as-received from the maker and after retrieval from a human body. Microstructural properties reveal significant gradients along the immediate material subsurface and distinct differences are found due to the loading history in vivo, which cannot be revealed by conventional optical spectroscopy. The applicability of the confocal spectroscopic technique is valid beyond the particular retrieval cases examined in this study, and can be easily extended to evaluate in-vitro tested components or to quality control of new polyethylene brands. Confocal Raman spectroscopy may also contribute to rationalize the complex effects of gamma-ray irradiation on the surface of medical grade UHMWPE for total joint replacement and, ultimately, to predict their actual lifetime in vivo.

40 CFR Appendix 7 to Subpart A of... - API Recommended Practice 13B-2

Code of Federal Regulations, 2010 CFR

2010-07-01

... facilitate cleaning and funnel-shaped top to catch falling drops. For compliance monitoring under the NPDES... condenser. b. Pack the retort body with steel wool. c. Apply lubricant/sealant to threads of retort cup and... the clean and dry liquid receiver. This is mass (C), grams. Place the receiver below condenser outlet...

40 CFR Appendix 7 to Subpart A of... - API Recommended Practice 13B-2

Code of Federal Regulations, 2011 CFR

2011-07-01

... facilitate cleaning and funnel-shaped top to catch falling drops. For compliance monitoring under the NPDES... condenser. b. Pack the retort body with steel wool. c. Apply lubricant/sealant to threads of retort cup and... the clean and dry liquid receiver. This is mass (C), grams. Place the receiver below condenser outlet...

[Mid-Term to Long-Term Results of Revision Total Hip Arthroplasty Using the Oval-Shaped Acetabular Cup - TC Type].

PubMed

Šťastný, E; Trč, T; Frýdl, J; Kopečný, Z; Philippou, T; Lisý, J

2017-01-01

INTRODUCTION The purpose of our paper is to evaluate the mid-term to long-term results and to confirm the basic criteria of a high-quality revision implant: safe bridging of bone defects, achievement of reliable primary fixation of revision acetabular cup, achievement of good secondary stability with documentable osteointegration of cup and demonstration of remodelling of transplanted bone tissue in the area of defects and in spaces between the implant ribs. MATERIAL AND METHODS Altogether 36 patients (38 cups) were evaluated who had undergone revision hip arthroplasty in the period from 2004 to 2010. The mean follow-up was 8.2 years (5.1-11.6 years after the reimplantation, more than 10 years in 16 patients who underwent surgery). The position and osseointegration of the implant were assessed by digital radiography, the remodelling of transplanted bone tissues in the area of defects and between the implant ribs by computed tomography with reducing artefacts around the metal implant (Aquilion 64 - Toshiba Medical Systems), and for the clinical outcomes the Harris Hip Score was used. RESULTS Preoperatively, the condition of the hip joint based on the Harris Hip Score was in 30 cases evaluated as poor, in 8 patients as satisfactory. At the time of final evaluation, 8 patients achieved excellent results, in 19 patients the condition of the joint was very good (in 2 patients bilaterally), in 6 patients it was considered satisfactory and in 3 patients poor. The mean value for HHS increased from 39.5 to 84.5. Based on the radiography evaluation, in 27 patients (in 2 patients bilaterally) the osseointegration of the revision cup was good, in 8 cases with a radiolucent line of 2-4 mm in width in DeLee zone III, in one case proximal migration of the cup occurred caused by deep infection. The informed consent form for pelvic CT was signed by 25 patients of our cohort. Remodelling of bone tissue in the space between the ribs of the implant was always detected, the presence of bone cysts was not reported, the bone defects following the application of autologous spongioplasty in the monitored patients were healed. In 6 patients, an ingrowth of fibrous tissue of 2-4 mm in width in the convexity of the cup was detected. The mean survival of the revision oval-shaped cup - TC type with a follow-up of 8.2 years after the reimplantation based on Kaplan-Meier analysis was 91.4 %. DISCUSSION The number of revision total hip arthroplasties due to a younger age of patients who undergo alloplasty keeps growing. The choice of a revision implant should always match the intraoperative finding and the bone tissue quality. The standard uncemented implants with osteoactive surface can be opted for when anterior and posterior column of the acetabulum are intact (IIA and IIB according to Paprosky). Starting from type IIC, also the proximal part of acetabulum shall be considered. At our department, preference is given to the revision cup - TC type. The oval shape facilitates a lower degree of bone resection and easier restoration of the anatomical centre of rotation. Careful debridement of granulating and necrotic tissue, thorough treatment of bone defects and osteoactive surface of implants in case of adequate primary fixation of the cup substantially contribute to the quality of its osseointegration. Greater rigidity of fixation verified by pull-out tests enables to insert angular stable screws into the gaps in the proximal part of the cup. There is still room for improvement in treating the bone defect. The application of allogenic bone grafts into the defects and spaces between the ribs of the TC cup is more challenging than the use of augmentation in the systems with trabecular titanium. Based on the evaluation of CT scans, remodelling of the transplanted bone occurs, therefore the defect zone is reduced. CONCLUSIONS The oval-shaped uncemented cup - type TC meets the requirements placed on a state-of the art revision implant, moreover its specific construction helps improve the conditions where another re-operation of acetabulum is necessary. By evaluating mid-term to long-term results of non-homogenous group of 36 patients (38 cups) we have obtained data on joint function comparable to similar groups with revision uncemented implants presented in our and foreign literature. Key words: revision oval-shaped cup, bone remodelling, pull-out tests, angular stable screws, computed tomography.

Outcomes and prognostic factors in revision hip arthroplasty for severe intra-pelvic cup protrusion: 246 cases.

PubMed

Epinette, J-A; Mertl, P; Combourieu, B; Goncalves, H; Blairon, A; Ehlinger, M; Tabutin, J

2015-10-01

The outcome of revision total hip arthroplasty (THA) for intra-pelvic cup protrusion is unclear. Hence, we conducted a large retrospective study to clarify the surgical strategy (hip lever arm and cup mechanical fixation) and the outcomes of reconstruction for severe intra-pelvic cup protrusion. We hypothesized that restoration of the anatomic hip centre in such acetabular revisions decreased the risk of recurrent loosening. The study included 246 THA procedures (in 220 patients), with a follow-up of 5.2 ± 4.9 years (1-24.2) after the index surgery. Bone loss was estimated using the SOFCOT classification (grade III or IV in 80% of cases) and the Paprosky classification (IIIA or IIIB in 58% of cases). Quality of the reconstruction was assessed on X-rays according to the correction of the protrusion and position of the hip centre of rotation. After a clinical follow-up of at least 5 years, with a mean of 9.9 ± 4.1 years (5-24 years), the mean Postel-Merle d'Aubigné score was 14.2 ± 3.1 and the mean Harris Hip Score was 78.0 ± 18.7. Cup protrusion was partially or completely corrected in every case and cup position was normal in 27 (11%) cases. The centre of rotation was within 10mm of the physiological position in 158 (64.2%) cases, acceptable in 77 (31.3%) cases, ascended in 9 (3.7%) cases, and worsened in 1 (0.4%) case. Revision for cup or cup and femoral failures was required in 24 (9.8%) cases. Cumulative survival rates with cup loosening as the endpoint were 88.5% after 5 years, 79.9% after 10 years, and 63.9% at last follow-up at 13.6 years. Our hypothesis that restoration of anatomic hip centre decreased the risk of recurrent loosening was not verified: success or failure in restoring the normal centre of rotation did not correlate significantly with final cup status. Recurrent aseptic loosening was the cause of failure in 9.8% of cases. Ensuring long-term effective mechanical stability had a greater impact on global outcomes than restoring an ideal centre of rotation. Copyright © 2015. Published by Elsevier Masson SAS.

Preload Loss in a Spacecraft Fastener via Vibration-Induced Unwinding

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher; Howard, S. Adam; Hess, Daniel P.

2018-01-01

Sound engineering practice requires that fasteners and bolted joints maintain preload in service. NASA recently concluded a series of vibration tests of a multicomponent structure intended to simulate an upper stage section of a launch vehicle. The stacked components were joined through six circumferentially placed bolted cup-cone-style pyrotechnic joint mechanisms designed to share spacecraft structural loads and then enable separation during ascent. Over the course of the vibration test campaign, all six bolted cup-cone mechanisms experienced some degree of preload loss with two mechanisms losing half of their original bolt preload. A subsequent forensic anomaly investigation concluded that vibration-induced unwinding of the preload nut-and-bolt assemblies occurred despite the use of safety wire and high levels of thread friction. A series of experiments were done to better understand how large, heavily preloaded fasteners could unwind. Additionally, thread friction torque was measured and the fastener locking capability of safety wire was evaluated. The friction coefficient between the clamped cup-cone components was characterized and finally a highly instrumented mechanism-level vibration test was done to reproduce the unwinding phenomenon to better understand the mechanism's behavior. The conclusion drawn was that vibration and structural forces led to relative motion (sliding) of the clamped components, resulting in self-loosening and unwinding effects on the nut-and-bolt assembly. To counter this phenomenon, more effective fastener locking methodologies were recommended and a follow-on effort was initiated to quantify the relationship between preload, component motion, and resulting unwinding forces. It is hoped that elucidation of these effects can be used to design more effective fastener locking features.

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.

[Total hip arthroplasty in post-dysplastic hip arthritis. Can type and position of the acetabular component influence longevity of the prosthesis?].

PubMed

Fousek, J; Indráková, P

2007-02-01

The aim of the study was a retrospective evaluation of our patients with post-dysplastic hips treated by cemented or non-cemented total hip arthroplasty (THA) in order to ascertain which type and position of the acetabular component was most effective. In the years 1999-2002, 111 THA procedures were performed in 93 patients, 76 women and 17 men, with post-dysplastic hip arthritis. The average age of the patients at the time of implantation was 52.6 years. On the basis of pre-operative radiographic findings, the patients' conditions were evaluated using the Hartofilakidis classification into three disease categories: dysplasia, low dislocation and high dislocation, and the patients were placed in two groups. Group 1 included 78 patients, and group 2 comprised 26 patients. None of our patients was classified as having high dislocation. Thirty-nine of these patients had previously undergone surgery for dysplastic hips. A total of 104 THAs were evaluated, because radiographic data was incomplete in seven cases. In addition to X-ray findings, the prosthesis type (cemented, hybrid, non-cemented), post-operative complications and signs of loosening were included in the evaluation. Clinical outcomes were assessed by the Harris score. The follow-up terminating on 31st December 2005 was 67 months on the average. In group 1 patients, the average Harris score increased from 38.6 to 80.3 points and in group 2 patients from 35.5 to 84.9 points, mostly with excellent and good results. In 72.1 % of the hips, a press-fit acetabular component was implanted. In 55.8 % of the cases, the acetabular component was implanted off the anatomical center of rotation, into the high hip center, with the range from 9 to 20 mm and an average of 15 mm. The average limb lengthening was 2.5 cm, ranging from 1.0 to 3.5 cm. Our results show that it is more effective to use non-cemented THA for post-dysplastic hips. The implantation of a noncemented acetabular component into the high center provides better covering of the cup with solid bone, without the necessity of cotyloplasty or structural graft use. Also, it does not markedly affect hip function or patients' subjective feelings.

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.

Birmingham Mid-Head Resection hip arthroplasty in a young man with gigantism.

PubMed

Murphy, Michael T; Shillington, Mark P; Mogridge, Damon R; Journeaux, Simon F

2012-02-01

The Birmingham Mid-Head Resection (Smith & Nephew Ltd, Warwick, United Kingdom) arthroplasty is a new bone-conserving procedure that, like hip resurfacing, is used in younger, active patients. We present the case of a young man with Sotos syndrome (cerebral gigantism) with associated extraordinary stature (height, 2.16 m; weight, 157 kg) who underwent Birmingham Mid-Head Resection arthroplasty. The large stature of this patient required a custom manufactured prosthesis (a femoral head 68 mm in diameter with an acetabular cup 76 mm in diameter). We believe this to be the largest metal-on-metal resurfacing articulation and hip arthroplasty reported to date. Copyright © 2012 Elsevier Inc. All rights reserved.

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.

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.

Is metal-on-metal squeaking related to acetabular angle of inclination?

PubMed

Bernasek, Thomas; Fisher, David; Dalury, David; Levering, Melissa; Dimitris, Kirk

2011-09-01

Postoperative audible squeaking has been well documented in ceramic-on-ceramic hip prostheses, and several metal-on-metal (MOM) THA designs, specifically those used for large-head resurfacing and MOM polyethylene sandwich designs, and are attributed to different implant- and patient-specific factors. Current literature does not identify the incidence of squeaking in modular MOM THA or possible etiologic factors. Our purposes were to (1) identify the incidence of squeaking in modular MOM prostheses in THA; (2) determine whether males or females were more likely to have squeaking; and (3) determine whether the incidence of squeaking relates to acetabular inclination angle. We retrospectively reviewed the patient records and radiographs of 539 patients (542 hips) from three independent centers who underwent a MOM THA between February 2001 and December 2005. Demographic and implant factors were evaluated, including measurement of cup inclination angles. The minimum followup was 36 months (mean, 76 months; range, 36-119 months). We identified squeaking in eight of the 542 hips (1.5%); five were in women and two were in men (one patient had bilateral squeaking). The time to onset of patient-reported audible squeaking averaged 23 months (range, 6-84 months). Squeaking was more likely to occur in women (six of eight hips). No hips with 45º or less acetabular inclination squeaked (291 hips); eight of 251 hips (3.2%) with inclination angles greater than 45º squeaked. Patients who reported squeaking had higher inclination angles than those who did not report squeaking. Our observations suggest an increased frequency of squeaking in female patients and in patients with greater inclination angles with this MOM implant design.

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

Insufficient acetabular version increases blood metal ion levels after metal-on-metal hip resurfacing.

PubMed

Hart, Alister J; Skinner, John A; Henckel, Johann; Sampson, Barry; Gordon, Fabiana

2011-09-01

Many factors affect the blood metal ion levels after metal-on-metal (MOM) hip arthroplasty. The main surgically adjustable variable is the amount of coverage of the head provided by the cup which is a function of the inclination and version angles. However, most studies have used plain radiographs which have questionable precision and accuracy, particularly for version and large diameter metal heads; further, these studies do not simultaneously assess version and inclination. Thus the relationship between version and blood metal ions levels has not been resolved. We determined whether cup inclination and version influence blood metal ion levels while adjusting for age at assessment, gender, body mass index, horizontal femoral offset, head size, manufacturer hip type, and Oxford hip score. We prospectively followed 100 individuals (51 females, 49 males) with unilateral MOM hip resurfacing who underwent clinical assessment, CT scanning, and blood metal ion measurement. Multiple regression analysis was used to determine which variables were predictors of blood metal ion levels and to model the effect of these variables. Only cup inclination, version angles, and gender influenced blood cobalt or chromium levels. Cobalt and chromium levels positively correlated with inclination angle and negatively correlated with version angle. The effect of changes in version angle was less than for inclination angle. Based on our observations, we developed a formula to predict the effect of these parameters on metal ion levels. Our data suggest insufficient cup version can cause high blood metal ions after MOM hip arthroplasty. We were unable to show that excessive version caused high levels. Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Backside Wear Analysis of Retrieved Acetabular Liners with a Press-Fit Locking Mechanism in Comparison to Wear Simulation In Vitro.

PubMed

Puente Reyna, Ana Laura; Jäger, Marcus; Floerkemeier, Thilo; Frecher, Sven; Delank, Karl-Stefan; Schilling, Christoph; Grupp, Thomas M

2016-01-01

Backside wear due to micromotion and poor conformity between the liner and its titanium alloy shell may contribute to the high rates of retroacetabular osteolysis and consequent aseptic loosening. The purpose of our study was to understand the wear process on the backside of polyethylene liners from two acetabular cup systems, whose locking mechanism is based on a press-fit cone in combination with a rough titanium conical inner surface on the fixation area. A direct comparison between in vitro wear simulator tests (equivalent to 3 years of use) and retrieved liners (average 13.1 months in situ) was done in order to evaluate the backside wear characteristics and behavior of these systems. Similar wear scores between in vitro tested and retrieved liners were observed. The results showed that this locking mechanism did not significantly produce wear marks at the backside of the polyethylene liners due to micromotion. In all the analyzed liners, the most common wear modes observed were small scratches at the cranial fixation zone directly below the rough titanium inner surface of the shell. It was concluded that most of the wear marks were produced during the insertion and removal of the liner, rather than during its time in situ.

Nuclear reactor fuel assembly duct-tube-to-handling-socket attachment system

DOEpatents

Christiansen, David W.; Smith, Bob G.

1982-01-01

A reusable system for removably attaching the upper end 10of a nuclear reactor duct tube to the lower end 30 of a nuclear reactor fuel assembly handling socket. A transition ring 20, fixed to the duct tube's upper end 10, has an interior-threaded section 22 with a first locking hole segment 24. An adaptor ring 40, fixed to the handling socket's lower end 30 has an outside-threaded section 42 with a second locking hole segment 44. The inside 22 and outside 42 threaded sections match and can be joined so that the first 24 and second 44 locking hole segments can be aligned to form a locking hole. A locking ring 50, with a locking pin 52, slides over the adaptor ring 40 so that the locking pin 52 fits in the locking hole. A swage lock 60 or a cantilever finger lock 70 is formed from the locking cup collar 26 to fit in a matching groove 54 or 56 in the locking ring 50 to prevent the locking ring's locking pin 52 from backing out of the locking hole.

Dynamic Hip Kinematics During the Golf Swing After Total Hip Arthroplasty.

PubMed

Hara, Daisuke; Nakashima, Yasuharu; Hamai, Satoshi; Higaki, Hidehiko; Ikebe, Satoru; Shimoto, Takeshi; Yoshimoto, Kensei; Iwamoto, Yukihide

2016-07-01

Although most surgeons allow their patients to play golf after total hip arthroplasty (THA), the effect on the implant during the golf swing is still unclear. To evaluate hip kinematics during the golf swing after THA. Descriptive laboratory study. Eleven hips in 9 patients who underwent primary THA were analyzed. All patients were right-handed recreational golfers, and these 11 hips included 6 right hips and 5 left hips. Periodic radiographic images of the golf swing were taken using a flat-panel x-ray detector. Movements of the hip joint and components were assessed using 3-dimensional-to-2-dimensional model-to-image registration techniques. Liner-to-neck contact and translation of the femoral head with respect to the acetabular cup (cup-head translation) were examined. Hip kinematics, orientation of components, and maximum cup-head translation were compared between patients with and without liner-to-neck contact. On average, the golf swing produced approximately 50° of axial rotation in both lead and trail hips. Liner-to-neck contact was observed in 4 hips with elevated rim liners (2 lead hips and 2 trail hips) at maximum external rotation. Neither bone-to-bone nor bone-to-implant contact was observed at any phases of the golf swing in any of the hips. Four hips with liner-to-neck contact had significantly larger maximum external rotation (37.9° ± 7.0° vs 20.6° ± 9.9°, respectively; P = .01) and more cup anteversion (26.5° ± 6.1° vs 10.8° ± 8.9°, respectively; P = .01) than hips without liner-to-neck contact. No significant differences between hips with and without contact were found for cup inclination (42.0° ± 2.5° vs 38.1° ± 5.5°, respectively; P = .22), combined anteversion (45.3° ± 8.9° vs 51.4° ± 7.9°, respectively; P = .26), or maximum cup-head translation (1.3 ± 0.3 mm vs 1.5 ± 0.4 mm, respectively; P = .61). In this analysis, the golf swing did not produce excessive hip rotation or cup-head translation in any hips. However, liner-to-neck contact during the golf swing was observed in 36% of the hips, with unknown effects on the long-term results. Golf is an admissible sport after THA because dynamic hip stability was observed. However, the implant position, especially cup anteversion and the use of elevated rim liners, promoted liner-to-neck contact. © 2016 The Author(s).

Spring loaded thermocouple module

DOEpatents

McKelvey, T.E.; Guarnieri, J.J.

1984-03-13

A thermocouple arrangement is provided for mounting in a blind hole of a specimen. The thermocouple arrangement includes a cup-like holder member, which receives an elongated thermal insulator, one end of which is seated at an end wall of the holder. A pair of thermocouple wires, threaded through passageways in the insulator, extend beyond the insulator member, terminating in free ends which are joined together in a spherical weld bead. A spring, held captive within the holder, applies a bias force to the weld bead, through the insulator member. The outside surface of the holder is threaded for engagement with the blind hole of the specimen. When the thermocouple is installed in the specimen, the spherical contact surface of the weld bead is held in contact with the end wall of the blind hole, with a predetermined bias force.

Spring loaded thermocouple module

DOEpatents

McKelvey, Thomas E.; Guarnieri, Joseph J.

1985-01-01

A thermocouple arrangement is provided for mounting in a blind hole of a specimen. The thermocouple arrangement includes a cup-like holder member, which receives an elongated thermal insulator, one end of which is seated at an end wall of the holder. A pair of thermocouple wires, threaded through passageways in the insulator, extend beyond the insulator member, terminating in free ends which are joined together in a spherical weld bead. A spring, held captive within the holder, applies a bias force to the weld bead, through the insulator member. The outside surface of the holder is threaded for engagement with the blind hole of the specimen. When the thermocouple is installed in the specimen, the spherical contact surface of the weld bead is held in contact with the end wall of the blind hole, with a predetermined bias force.

Numerical simulation of artificial hip joint motion based on human age factor

NASA Astrophysics Data System (ADS)

Ramdhani, Safarudin; Saputra, Eko; Jamari, J.

2018-05-01

Artificial hip joint is a prosthesis (synthetic body part) which usually consists of two or more components. Replacement of the hip joint due to the occurrence of arthritis, ordinarily patients aged or older. Numerical simulation models are used to observe the range of motion in the artificial hip joint, the range of motion of joints used as the basis of human age. Finite- element analysis (FEA) is used to calculate stress von mises in motion and observes a probability of prosthetic impingement. FEA uses a three-dimensional nonlinear model and considers the position variation of acetabular liner cups. The result of numerical simulation shows that FEA method can be used to analyze the performance calculation of the artificial hip joint at this time more accurate than conventional method.

Accuracy and reproducibility of preoperative three-dimensional planning for total hip arthroplasty using biplanar low-dose radiographs : A pilot study.

PubMed

Mainard, D; Barbier, O; Knafo, Y; Belleville, R; Mainard-Simard, L; Gross, J-B

2017-06-01

In total hip arthroplasty (THA), the acetabular cup and femoral stem must be correctly sized and positioned to avoid intraoperative and postoperative complications, achieve good functional outcomes and ensure long-term survival. Current two-dimensional (2D) techniques do not provide sufficient accuracy, while low-dose biplanar X-rays (EOS) had not been assessed in this indication. Therefore, we performed a case-control study to : (1) evaluate the prediction of stem and cup size for a new 3D planning technique (stereoradiographic imaging plus 3D modeling) in comparison to 2D templating on film radiographs and (2) evaluate the accuracy and reproducibility of this 3D technique for preoperative THA planning. Accuracy and reproducibility are better with the 3D vs. 2D method. Stem and cup sizes were retrospectively determined by two senior surgeons, twice, for a total of 31 unilateral primary THA patients in this pilot study, using 3D preplanning software on low-dose biplanar X-rays and with 2D templating on conventional anteroposterior (AP) film radiographs. Patients with a modular neck or dual-mobility prosthesis were excluded. All patients but one had primary osteoarthritis; one following trauma did not have a cup implanted. The retrospectively planned sizes were compared to the sizes selected during surgery, and intraclass coefficients (ICC) calculated. 3D planning predicted stem size more accurately than 2D templating: stem sizes were planned within one size in 26/31 (84%) of cases in 3D versus 21/31 (68%) in 2D (P=0.04). 3D and 2D planning accuracies were not significantly different for cup size: cup sizes were planned within one size in 28/30 (92%) of cases in 3D versus 26/30 (87%) in 2D (P=0.30). ICC for stem size were 0.88 vs. 0.91 for 3D and 2D, respectively. Inter-operator ICCs for cup size were 0.84 vs. 0.71, respectively. Repetitions of the 3D planning were within one size (except one stem), with the majority predicting the same size. Increased accuracy in 3D may be due to the use of actual size (non-magnified) images, and judging fit on AP and lateral images simultaneously. Results for other implant components may differ from those presented. Size selection may improve further with planning experience, based on a feedback loop between planning and surgical execution. Level III. Retrospective case-control study. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Outcomes of dual mobility cups in a young Middle Eastern population and its influence on life style.

PubMed

Assi, Chahine; El-Najjar, Elie; Samaha, Camille; Yammine, Kaissar

2017-03-01

Dual mobility cups (DMC) in total hip arthroplasty (THA) are becoming popular among orthopaedic surgeons. Substantial benefit of their use has been reported among high risk patients, particularly in reducing post-operative hip instability (dislocation). Many reports stated some concern when implanted in young and active people where complications such as polyethylene wear and mechanical loosening could potentially be higher. This Middle Eastern study analyses a retrospective series of THA for any aetiology other than infection, using DMC for the acetabular component in 75 patients (85 implants) less than 70 years old. No instability, intra-prosthetic dislocation or mechanical failure was reported during a mean follow-up of five years. The only major complication was a post-operative infection. The mean post- operative modified Harris hip score was 97.1 out of 100. All patients resumed their daily activities and all religious practicing patients were able to accomplish their prayer positions without pain. DMC is found to be an interesting option in reducing dislocation events in young patients. Those excellent short-term results would encourage surgeons to use DMC in an active and highly demanding population. Further research is necessary to confirm maintenance of such results at long term follow-up.

Design of a hip prosthetic tribometer based on salat gait cycle

NASA Astrophysics Data System (ADS)

Towijaya, T.; Ismail, R.; Jamari, J.

2017-01-01

Indonesia is the country with the largest muslim population in the world, most of the inhabitants do salat every day. THR (Total Hip Replacement) patients are prohibited from doing salat in normal gait. It leads to the damage of the hip joint prostheses due to impingement and dislocation.This paper reports the design of a pin-on-ring tribometer which is used to measure and analyze the wear volume and the impingement of hip joint prostheses during salat. The modifications of the femoral head and acetabular cup holder are performed to design the reciprocating motion for the movement of the hip prostheses. The interesting finding of the present research is a new mechanism of linked-bar which leads to the feasibility of the measurement of the wear volume and the impingement for THR patients during salat.

The John Charnley Award: an accurate and sensitive method to separate, display, and characterize wear debris: part 1: polyethylene particles.

PubMed

Billi, Fabrizio; Benya, Paul; Kavanaugh, Aaron; Adams, John; Ebramzadeh, Edward; McKellop, Harry

2012-02-01

Numerous studies indicate highly crosslinked polyethylenes reduce the wear debris volume generated by hip arthroplasty acetabular liners. This, in turns, requires new methods to isolate and characterize them. We describe a method for extracting polyethylene wear particles from bovine serum typically used in wear tests and for characterizing their size, distribution, and morphology. Serum proteins were completely digested using an optimized enzymatic digestion method that prevented the loss of the smallest particles and minimized their clumping. Density-gradient ultracentrifugation was designed to remove contaminants and recover the particles without filtration, depositing them directly onto a silicon wafer. This provided uniform distribution of the particles and high contrast against the background, facilitating accurate, automated, morphometric image analysis. The accuracy and precision of the new protocol were assessed by recovering and characterizing particles from wear tests of three types of polyethylene acetabular cups (no crosslinking and 5 Mrads and 7.5 Mrads of gamma irradiation crosslinking). The new method demonstrated important differences in the particle size distributions and morphologic parameters among the three types of polyethylene that could not be detected using prior isolation methods. The new protocol overcomes a number of limitations, such as loss of nanometer-sized particles and artifactual clumping, among others. The analysis of polyethylene wear particles produced in joint simulator wear tests of prosthetic joints is a key tool to identify the wear mechanisms that produce the particles and predict and evaluate their effects on periprosthetic tissues.

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.

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.

A hip joint simulator study using simplified loading and motion cycles generating physiological wear paths and rates.

PubMed

Barbour, P S; Stone, M H; Fisher, J

1999-01-01

In some designs of hip joint simulator the cost of building a highly complex machine has been offset with the requirement for a large number of test stations. The application of the wear results generated by these machines depends on their ability to reproduce physiological wear rates and processes. In this study a hip joint simulator has been shown to reproduce physiological wear using only one load vector and two degrees of motion with simplified input cycles. The actual path of points on the femoral head relative to the acetabular cup were calculated and compared for physiological and simplified input cycles. The in vitro wear rates were found to be highly dependent on the shape of these paths and similarities could be drawn between the shape of the physiological paths and the simplified elliptical paths.

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.

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.

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.

Treatment of Crowe Type-IV Hip Dysplasia Using Cementless Total Hip Arthroplasty and Double Chevron Subtrochanteric Shortening Osteotomy: A 5- to 10-Year Follow-Up Study.

PubMed

Li, Xigong; Lu, Yang; Sun, Junying; Lin, Xiangjin; Tang, Tiansi

2017-02-01

The purpose of this study was to evaluate the functional and radiographic results of patients with Crowe type-IV hip dysplasia treated by cementless total hip arthroplasty and double chevron subtrochanteric osteotomy. From January 2000 to February 2006, cementless total hip arthroplasty with a double chevron subtrochanteric shortening osteotomy was performed on 18 patients (22 hips) with Crowe type-IV dysplasia. The acetabular cup was placed in the position of the anatomic hip center, and subtrochanteric femoral shortening osteotomy was performed with the use of a double chevron design. The clinical and radiographic outcomes were reviewed with a mean follow-up of 6.5 years (5-10 years). The mean amount of femoral subtrochanteric shortening was 38 mm (25-60 mm). All osteotomy sites were healed by 3-6 months without complications. The mean Harris Hip Score improved significantly from 47 points (35-65 points) preoperatively to 88 points (75-97 points) at the final follow-up. The Trendelenburg sign was corrected from a positive preoperative status to a negative postoperative status in 12 of 22 hips. No acetabular and femoral components have loosened or required revision during the period of follow-up. Cementless total hip arthroplasty using double chevron subtrochanteric osteotomy allowed for restoration of anatomic hip center with safely functional limb lengthening, achieved correction of preoperative limp, and good functional and radiographic outcomes for 22 Crowe type-IV dislocation hips at the time of the 5- to 10-year follow-up. Copyright © 2016 Elsevier Inc. All rights reserved.

Reducing the rate of early primary hip dislocation by combining a change in surgical technique and an increase in femoral head diameter to 36 mm.

PubMed

Ho, Ki Wai Kevin; Whitwell, George S; Young, Steve K

2012-07-01

We report how changes to our total hip arthroplasty (THA) surgical practise lead to a decrease in early hip dislocation rates. Group B consisted of 421 consecutive primary THA operations performed via a posterior approach. The operative technique included a meticulous repair of the posterior capsule, alignment of the acetabular cup with the transverse acetabular ligament (TAL) and a 36-mm-diameter femoral head. We compared the dislocation rates and cost implications of this technique to a historical control Group A consisting of 389 patients. The control group had their THA performed with no repair of the capsule, no identification of the TAL and all received a 28-mm-diameter head. Our primary outcome is the rate of early hip dislocation and we hypothesised that we can reduce the rate of early hip dislocation with this new regime. In Group B there were no early dislocations (within 6 months) and two (0.5 %) dislocations within 18 months; minimum follow-up time was 18 months with a range of (18-96 months). This compared to a 1.8 % early dislocation rate and a 2.6 % rate at 18 months in Group A; minimum follow-up time was 60 months with a range of (60-112 months). These results were statistically significant (p = 0.006). We suggest that when primary hip arthroplasty is performed through a posterior approach, a low early dislocation rate can be achieved using the described methods.

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

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint (hemi-hip) acetabular metal cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip) acetabular...

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.

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

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint (hemi-hip) acetabular metal cemented... (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip) acetabular metal cemented prosthesis is a device intended to be implanted to replace a portion of the hip joint...

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.

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.

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.

Pelvic orientation for total hip arthroplasty in lateral decubitus: can it be accurately measured?

PubMed

Sykes, Alice M; Hill, Janet C; Orr, John F; Gill, Harinderjit S; Salazar, Jose J; Humphreys, Lee D; Beverland, David E

2016-05-16

During total hip arthroplasty (THA), accurately predicting acetabular cup orientation remains a key challenge, in great part because of uncertainty about pelvic orientation. This pilot study aimed to develop and validate a technique to measure pelvic orientation; establish its accuracy in the location of anatomical landmarks and subsequently; investigate if limb movement during a simulated surgical procedure alters pelvic orientation. The developed technique measured 3-D orientation of an isolated Sawbone pelvis, it was then implemented to measure pelvic orientation in lateral decubitus with post-THA patients (n = 20) using a motion capture system. Orientation of the isolated Sawbone pelvis was accurately measured, demonstrated by high correlations with angular data from a coordinate measurement machine; R-squared values close to 1 for all pelvic axes. When applied to volunteer subjects, largest movements occurred about the longitudinal pelvic axis; internal and external pelvic rotation. Rotations about the anteroposterior axis, which directly affect inclination angles, showed >75% of participants had movement within ±5° of neutral, 0°. The technique accurately measured orientation of the isolated bony pelvis. This was not the case in a simulated theatre environment. Soft tissue landmarks were difficult to palpate repeatedly. These findings have direct clinical relevance, landmark registration in lateral decubitus is a potential source of error, contributing here to large ranges in measured movement. Surgeons must be aware that present techniques using bony landmarks to reference pelvic orientation for cup implantation, both computer-based and mechanical, may not be sufficiently accurate.

Dual mobility cups provide biomechanical advantages in situations at risk for dislocation: a finite element analysis.

PubMed

Terrier, Alexandre; Latypova, Adeliya; Guillemin, Maika; Parvex, Valérie; Guyen, Olivier

2017-03-01

Constrained devices, standard implants with large heads, and dual mobility systems have become popular options to manage instability after total hip arthroplasty (THA). Clinical results with these options have shown variable success rates and significant higher rates of aseptic loosening and mechanical failures with constrained implants. Literature suggests potential advantages of dual mobility, however little is known about its biomechanics. We present a comparative biomechanical study of a standard implant, a constrained implant, and a dual mobility system. A finite element analysis was developed to assess and compare these acetabular options with regard to the range of motion (ROM) to impingement, the angle of dislocation, the resistive torque, the volume of polyethylene (PE) with a stress above 80% of the elastic limit, and the interfacial cup/bone stress. Dual mobility implants provided the greatest ROM to impingement and allowed delaying subluxation and dislocation when compared to standard and constrained implants. Dual mobility also demonstrated the lowest resistive torque at subluxation while the constrained implant provided the greatest one. The lowest critical PE volume was observed with the dual mobility implant, and the highest stress at the interfaces was observed with the constrained implant. This study highlights the biomechanical advantages of dual mobility systems over constrained and standard implants, and is supported by the clinical results reported. Therefore, the use of dual mobility systems in situations at risk for instability should be advocated and constrained implants should be restricted to salvage situations.

Instability of total hip replacement: A clinical study and determination of its risk factors.

PubMed

Ezquerra-Herrando, L; Seral-García, B; Quilez, M P; Pérez, M A; Albareda-Albareda, J

2015-01-01

To determine the risk factors associated with prosthetic dislocation and simulate a finite element model to determine the safe range of movement of various inclination and anteversion cup positions. Retrospective Case Control study with 46 dislocated patients from 1994 to 2011. 83 randomly selected patients. Dislocation risk factors described in the literature were collected. A prosthetic model was simulated using finite elements with 28, 32, 36 mm heads, and a 52 mm cup. Acetabular position was 25°, 40°, and 60° tilt and with 0°, 15° and 25° anteversion. In extension of 0° and flexion of 90°, internal and external rotation was applied to analyze the range of movement, maximum resisting moment, and stress distribution in the acetabulum to impingement and dislocation. There was greater dislocation in older patients (p=0.002). Higher dislocation in fractures than in osteoarthritis (p=0.001). Less anteversion in dislocated patients (p=0.043). Longer femoral neck in dislocated patients (p=0.002). Finite element model: lower dislocation when there is more anteversion, tilt and bigger femoral heads. Advanced age and fractures are the major risk factors for dislocation. "Safe zone" of movement for dislocation avoidance is 40°-60° tilt and 15°-25° anteversion. Both the defect and excess of soft tissue tension predispose to dislocation. Bigger femoral heads are more stable. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

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

Investigation of Wear and Corrosion of a High-Carbon Stellite Alloy for Hip Implants

NASA Astrophysics Data System (ADS)

Hu, P. S.; Liu, R.; Liu, J.; McRae, G.

2014-04-01

Low-carbon Stellite 21 has been used as hip implant material for a number of decades; however, its limited metal-on-metal bearing has resulted in loosening between the femoral head and the acetabular cup of hip implants. In order to improve the metal-on-metal bearing, it is proposed that a high-carbon alloy, Stellite 720, surface coating be applied on Stellite 21 hip implants to improve mechanical and tribological performance. For this coating to be practical, it must also meet the requirements of corrosion resistance for orthopedic implant materials. In this research, Stellite 720 is investigated with pin-on-disk wear tests, and electrochemical and immersion corrosion tests in simulated human body fluid (Hank's solution; pH 7.4 at temperature of 37°C). The experimental results demonstrate that Stellite 720 exhibits much better wear resistance than Stellite 21, and has the potential for better corrosion resistance as well. The applicability of coating Stellite 21 hip implants with Stellite 720 is discussed.

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.

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.

Predicting high blood metal ion concentrations following hip resurfacing.

PubMed

Matharu, Gulraj S; Berryman, Fiona; Brash, Lesley; Pynsent, Paul B; Treacy, Ronan B C; Dunlop, David J

2015-01-01

To determine whether gender, femoral head size, acetabular inclination, and time since surgery predicted high blood metal ion concentrations following Birmingham Hip Resurfacing (BHR). BHR patients with unilateral bearings at one specialist centre with blood cobalt and chromium concentrations measured up to May 2013 were included. This comprised a mixed (at-risk) group including symptomatic patients and asymptomatic individuals with specific clinical and/or radiological findings. Blood sampling was at a mean of 7.5 years (range 1-15.4 years) postoperatively. Of 319 patients (mean age 49.3 years; 53% male), blood metal ions greater than 7 µg/l were observed in 9% (n = 28). Blood metal ions were significantly higher in females (p<0.001), femoral head sizes ≤48 mm (p<0.01), and cup inclinations >55° (p<0.001). Linear regression demonstrated femoral head size was responsible for the highest proportion of variance in blood metal ions (cobalt p<0.001, R2 = 8%; chromium p<0.001, R2 = 11%). Analysis of femoral head size and inclination together demonstrated 36% of BHRs with head sizes of 38-44 mm and inclination >55° had blood metal ions >7 µg/l. BHR 10-year survival for this at-risk group was 91% (95% confidence intervals 86.0%-95.0%) with 30 hips revised. If blood metal ions are used to screen hip resurfacing patients for adverse reactions to metal debris it is recommended those with small femoral head sizes (38-44 mm) and high acetabular inclinations (>55°) are targeted. These findings require validation in other cohorts as they may not be applicable to all hip resurfacing devices given the differences in radial clearance, coverage arc, and metallurgy.

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.

Adverse Reactions to Metal on Metal Are Not Exclusive to Large Heads in Total Hip Arthroplasty.

PubMed

Lombardi, Adolph V; Berend, Keith R; Adams, Joanne B; Satterwhite, Keri L

2016-02-01

There is some suggestion that smaller diameter heads in metal-on-metal total hip arthroplasty (MoM THA) may be less prone to the adverse reactions to metal debris (ARMD) seen with large-diameter heads. We reviewed our population of patients with small head (≤ 32 mm) MoM THA to determine (1) the frequency of ARMD; (2) potential risk factors for ARMD in this population; and (3) the etiology of revision and Kaplan-Meier survivorship with revision for all causes. Small-diameter head MoM devices were used in 9% (347 of 3753) of primary THAs during the study period (January 1996 to March 2005). We generally used these implants in younger, more active, higher-demand patients. Three hundred hips (258 patients) had MoM THA using a titanium modular acetabular component with a cobalt-chromium tapered insert and were available for review with minimum 2-year followup (mean, 10 years; range, 2-19 years). Complete followup was available in 86% of hips (300 of 347). Clinical records and radiographs were reviewed to determine the frequency and etiology of revision. Kaplan-Meier survivorship analysis was performed. ARMD frequency was 5% (14 of 300 hips) and represented 70% (14 of 20) of revisions performed. Using multivariate analysis, no variable tested, including height, weight, body mass index, age, cup diameter, cup angle, use of screws, stem diameter, stem type, head diameter, preoperative clinical score, diagnosis, activity level, or sex, was significant as a risk factor for revision. Twenty hips have been revised: two for infection, four for aseptic loosening, and 14 for ARMD. Kaplan-Meier analysis revealed survival free of component revision for all causes was 95% at 10 years (95% confidence interval [CI], 91%-97%), 92% at 15 years (95% CI, 87%-95%), and 72% at 19 years (95% CI, 43%-90%), and survival free of component revision for aseptic causes was 96% at 10 years (95% CI, 92%-98%), 92% at 15 years (95% CI, 88%-95%), and 73% at 19 years (95% CI, 43%-90%). The late onset and devastating nature of metal-related failures is concerning with this small-diameter MoM device. Although the liner is modular, it cannot be exchanged and full acetabular revision is required. Patients with all MoM THA devices should be encouraged to return for clinical and radiographic followup, and clinicians should maintain a low threshold to perform a systematic evaluation. Symptomatic patients should undergo thorough investigation and vigilant observation for ARMD. Level IV, therapeutic study.

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.

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.

Anterior total hip arthroplasty using a metaphyseal bone-sparing stem: component alignment and early complications.

PubMed

Ahmed, Mohammed M; Otto, Thomas J; Moed, Berton R

2016-04-22

Limited-incision total hip arthroplasty (THA) preserves hip abductors, posterior capsule, and external rotators potentially diminishing dislocation risk. However, potential complications also exist, such as component malposition. Specific implants have been manufactured that enhance compatibility with this technique, while preserving metaphyseal bone; however, little data exists documenting early complications and component position. The purpose was to evaluate primary THA using a curved, bone-sparing stem inserted through the anterior approach with respect to component alignment and early complications. In a retrospective analysis of 108 cases, the surgical technique was outlined and the occurrence of intraoperative fractures, postoperative dislocations, infection, and limb length inequality was determined. Femoral stem and acetabular cup alignment was quantified using the initial postoperative radiographs. Patient follow-up averaged 12.9 (range 2 to 36) months. There were eight (7.4 %) complications requiring revision surgery in three (2.8 %) patients with three (2.8 %) infections and three (2.8 %) dislocations. Intraoperative complications included one calcar fracture above the lesser trochanter. Leg length inequality >5 mm was present in three (2.8 %) patients. Radiographic analysis showed that femoral neutral alignment was achieved in 95 hips (88.0 %). All femoral stems demonstrated satisfactory fit and fill and no evidence of subsidence, osteolysis, or loosening. An average abduction angle of 44.8° (± 5.3) and average cup anteversion of 16.2° (± 4.2) were also noted. Although the technique with this implant and approach is promising, it does not appear to offer important advantages over standard techniques. However, the findings merit further, long-term study.

Effect of progressive wear on the contact mechanics of hip replacements--does the realistic surface profile matter?

PubMed

Wang, Ling; Yang, Wenjian; Peng, Xifeng; Li, Dichen; Dong, Shuangpeng; Zhang, Shu; Zhu, Jinyu; Jin, Zhongmin

2015-04-13

The contact mechanics of artificial metal-on-polyethylene hip joints are believed to affect the lubrication, wear and friction of the articulating surfaces and may lead to the joint loosening. Finite element analysis has been widely used for contact mechanics studies and good agreements have been achieved with current experimental data; however, most studies were carried out with idealist spherical geometries of the hip prostheses rather than the realistic worn surfaces, either for simplification reason or lacking of worn surface profile. In this study, the worn surfaces of the samples from various stages of hip simulator testing (0 to 5 million cycles) were reconstructed as solid models and were applied in the contact mechanics study. The simulator testing results suggested that the center of the head has various departure value from that of the cup and the value of the departure varies with progressively increased wear. This finding was adopted into the finite element study for better evaluation accuracy. Results indicated that the realistic model provided different evaluation from that of the ideal spherical model. Moreover, with the progressively increased wear, large increase of the contact pressure (from 12 to 31 MPa) was predicted on the articulating surface, and the predicted maximum von Mises stress was increased from 7.47 to 13.26 MPa, indicating the marked effect of the worn surface profiles on the contact mechanics of the joint. This study seeks to emphasize the importance of realistic worn surface profile of the acetabular cup especially following large wear volume. Copyright © 2015 Elsevier Ltd. 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.

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.

[A simulative biomechanical experiment on different position of none-cement acetabular components influencing the load distribution around acetabulum].

PubMed

Li, Dongsong; Liu, Jianguo; Li, Shuqiang; Fan, Honghui; Guan, Jikui

2008-02-01

In the present study, a three dimensional finite-element model of the human pelvic was reconstructed, and then, under different acetabular component position (the abduction angle ranges from 30 degrees to 70 degrees and the anteversion ranges from 5 degrees to 30degrees) the load distribution around the acetabular was evaluated by the computer biomechanical analysis program (Solidworks). Through the obtained load distribution results, the most even and reasonable range of the distribution was selected; therefore the safe range of the acetabular component implantation can be validated from the biomechanics aspect.

[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.

21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/metal semi-constrained, with a... Devices § 888.3320 Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular...

21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/metal semi-constrained, with a... Devices § 888.3320 Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular...

[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.

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.

Microstructural disintegration in dense hydroxyapatite and hydroxyapatite-coated metal implants

NASA Astrophysics Data System (ADS)

Seo, Dong Seok; Lee, Jong Kook

2007-08-01

Hydroxyapatite (HA) has been widely used as a coating for orthopedic metal implants. An important concern regarding HA coating is its degradation of the biological milieu. In this study, the microstructure of a retrieved HA-coated acetabular cup implanted for four years after total hip arthroplasty (THA) was investigated by field emission scanning electron microscopy. In order to understand the underlying mechanism, of degradation and exfoliation of the HA coating, degradation of phase-pure and dense HA ceramics was also observed by in vitro and in vivo testing. The surface morphology and fracture surfaces of HA ceramics revealed that the dissolution starting at the surface extended inwards resulting in particle loosening and microstructural-level degradation. The dissolution features of HA ceramics were similar to the case of HA coating. It was found that extensive dissolution of the coating occurred and most of the coating disappeared. The majority of the remaining graints were fractured by the intergranular mode, suggesting that grain boundaries should be predominantly dissolved. These observations may explain the mechanism through which the biological stability of the HA coated layer becomes unexpectedly poor.

A Morlet wavelet signal analysis with a Daubechies filter for the wear assessment of hip prostheses coated with diamond-like carbon by triboadhesion.

PubMed

Rodríguez-Lelis, Jose Maria; Mata, Dagoberto Tolosa; Vargas-Treviño, Marciano; Navarro-Torres, Jose; Piña-Piña, Gilberto; Abundez-Pliego, Arturo

2010-08-01

In the present work, based on high frequency wavelet analysis of dynamic signals of mechanical systems, a multiple-resolution wavelet analysis is carried out, to the signal obtained from an accelerometer mounted on the structure of a hip prosthesis wearing test device. The prostheses employed had a femoral head made of aluminum oxide and the acetabular cup of ultra-high-molecular-weight polyethylene. The first two aluminum oxide femoral heads were coated with diamond-like carbon and a third one was tested without coating and used as a reference. The coating was carried out by triboadhesion. Tests results showed that maximum vibration amplitude reached after 32 hr for the coated prostheses was 0.2 g. The noncoated prosthesis amplitude presented was 0.75 g in the same time interval. These values were attributed to wear damage on the surface of the prostheses, indicating that thin film DLC coating caused an increase of stiffness on the surface and therefore an increase in wear resistance approximately of 314%.

Numerical study of the influence of the thickness and roughness of TiN coatings on their wear in scratch testing

NASA Astrophysics Data System (ADS)

Eremina, G. M.; Smolin, A. Yu.

2017-12-01

One of the mostly used and complicated surgical operations on large human joints is total hip replacement. An endoprosthesis is chosen individually for each person on the basis of his anatomical features and physical activity. However, such an important factor affecting the durability of an endoprosthesis as wear in the head-acetabular cup friction pair is still poorly understood, and it is taken into account only qualitatively. The determining role in wear belongs to the structure of the surface layers and coatings of the friction pair. The mechanical and structural characteristics of the coating largely depend on the method of its application. In this paper, to study the tribological characteristics of the coating material of the friction pair, we use computer simulation of scratch testing. The simulations are performed with the application of the method of movable cellular automata. The model specimens correspond to real coatings manufactured under different treatment conditions (deposition temperature and time). The analysis of the simulation results allows one to choose the optimal regime corresponding to the maximum hardness of coatings or adhesive strength.

Does a titanium sleeve reduce the frequency of pseudotumors in metal-on-metal total hip arthroplasty at 5-7years follow-up?

PubMed

Hjorth, M H; Egund, N; Mechlenburg, I; Gelineck, J; Jakobsen, S S; Soballe, K; Stilling, M

2016-12-01

Little is known about pseudotumor frequency and risk factors for pseudotumor formation among different types of metal-on-metal (MoM) hip arthroplasties. A lower release of chromium and cobalt have been reported in MoM hip arthroplasties with a titanium sleeve compared to MoM designs without a titanium sleeve, but yet it is unknown whether a titanium sleeve reduces the pseudotumor frequency. We conducted a cross-sectional study to investigate: 1) pseudotumor frequency, 2) risk factors of pseudotumor formation 3) and correlations between pseudotumors, serum metal-ions, implant position, and clinical symptoms. We expected a lower pseudotumor frequency in MoM hip articulation with a titanium sleeve than reported in MoM hip articulation designs using chromium-cobalt sleeve. A consecutive series of 41 patients/49 hips (31 males), mean age 52 (28-68) years, participated in a 5.5±0.5 (4-6.5) year follow-up study of their M2a_Magnum hip articulation (Biomet Inc., Warsaw, Indiana, USA). Patients were evaluated with magnetic resonance imaging (MRI), measurements of serum metal-ions, plain radiographs, and clinical outcome measures of Harris Hip Score (HHS) and Oxford Hip Score (OHS). Eighteen of 47 hips (38%) had MRI-verified pseudotumors, all cystic, with a mean dimension of 10.6×25.6×41mm. Digital measurements on plain radiographs revealed a higher cup anteversion in patients with a pseudotumor of mean 28.4°±5.05° compared to mean 23.5°±6.5° in patients without a pseudotumor (P=0.009). Serum metal-ion concentrations, acetabular cup inclination and measures of HHS and OHS were similar between patients with and without a pseudotumor (P>0.46). At 5.5±0.5years after surgery, MRI-verified cystic pseudotumors were frequently observed in M2a_Magnum hip articulations despite the use of titanium sleeves. The pseudotumors were related to high cup anteversion angles but not related to high serum metal-ions or clinical symptoms. IV: cross-sectional study. Copyright © 2016 Elsevier Masson SAS. 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.

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.

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.

In situ observation of lubricant film formation in THR considering real conformity: The effect of diameter, clearance and material.

PubMed

Nečas, D; Vrbka, M; Urban, F; Gallo, J; Křupka, I; Hartl, M

2017-05-01

The aim of the present study is to provide an analysis of protein film formation in hip joint replacements considering real conformity based on in situ observation of the contact zone. The main attention is focused on the effect of implant nominal diameter, diametric clearance and material. For this purpose, a pendulum hip joint simulator equipped with electromagnetic motors enabling to apply continuous swinging flexion-extension motion was employed. The experimental configuration consists of femoral component (CoCrMo, BIOLOX®forte, BIOLOX®delta) and acetabular cup from optical glass fabricated according to the dimensions of real cups. Two nominal diameters were studied, 28 and 36mm, respectively, while different diametric clearances were considered. Initially, a static test focused on the protein adsorption onto rubbing surfaces was performed with 36mm implants. It was found that the development of adsorbed layer is much more stable in the case of metal head, indicating that the adsorption forces are stronger compared to ceramic. A consequential swinging test revealed that the fundamental parameter influencing the protein film formation is diametric clearance. Independently of implant diameter, film was much thicker when a smaller clearance was considered. An increase of implant size from 28mm to 36mm did not cause a substantial difference in film formation; however, the total film thickness was higher for smaller implant. In terms of material, metal heads formed a thicker film, while this fact can be, among others, also attributed to clearance, which is more than two times higher in the case of ceramic implant. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Medium-term results of ceramic-on-polyethylene Zweymüller-Plus total hip arthroplasty.

PubMed

Li, H; Zhang, S; Wang, X M; Lin, J H; Kou, B L

2017-08-01

The need for better durability and longevity in total hip arthroplasty for patients with various hip joint diseases remains a challenge. This study aimed to obtain medium-term results at a follow-up of >10 years for Zweymüller-Plus total hip arthroplasty with ceramic-on-polyethylene bearing. A retrospective study was conducted to review the results after a minimum of 12.4 years of 207 consecutive total hip arthroplasties in 185 patients in Peking University People's Hospital in China using the Zweymüller SL-Plus stem in combination with the Bicon-Plus threaded cup and ceramic-on-polyethylene bearing between October 1994 and April 2000. During the study period, two patients (2 hips) died and 25 patients (28 hips) were lost to follow-up. Two hips were revised for aseptic loosening of the Bicon-Plus cup. The mean clinical and radiological follow-up was 14.1 years (range, 12.4-16.5 years) for the remaining 156 patients (175 hips). The mean (standard deviation) Harris Hip score for the 175 hips increased significantly from 39.3 (3.8) preoperatively to 94.1 (2.5) postoperatively at a mean follow-up of 14.1 years (P<0.05). Focal osteolysis was observed in seven (4.0%) of 175 stems and three (1.7%) of 175 cups. The Kaplan-Meier survival with revision for any reason as the end-point was 99.03% (95% confidence interval, 95%-100%). The high survival rate of the cementless Zweymüller-Plus system with ceramic-on-polyethylene bearing at mid-term follow-up makes this total hip arthroplasty system reliable for patients with various hip joint diseases.

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.

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.

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.

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.

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

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 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.

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.

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

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

[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.

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.

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.

[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.

Design and implementation of a prototype micropositioning and fusion of optical fibers

NASA Astrophysics Data System (ADS)

Vega, Fabio; Torres, Cesar; Mattos, Lorenzo

2011-09-01

We developed an automated system in micro and optical fiber fusion, using stepper motors of 3.6 ° (1.8 ° Medium step) with a threaded system for displacements in the order of microns, a LM016 LCD for User message management, a PIC16F877A microcontroller to control the prototype. We also used internal modules: TMR0, EEPROM, PWM (pulse width modulation) control using a pulse opto-cupped the discharge circuit high voltage (20 to 35 kilovolt transformer for FLYBACK fusion) The USART (Universal Synchronous Asynchronous Receiver Transmitter) for serial interface with the PC. The software platform developed under Visual Basic 6.0, which lets you manipulate the prototype from the PC. The entire program is optimized for microcontroller interrupt, macro-functions and is written in MPLAB 7.31. The prototype is now finished.

The Extended Direct Anterior Approach for Column Augmentation in the Deficient Pelvis: A Novel Surgical Technique, and Case Series Report.

PubMed

Spanyer, Jonathon M; Beaumont, Christopher M; Yerasimides, Jonathan G

2017-02-01

Anterior column deficiency of the pelvis may pose a serious threat to the stability of the acetabular component after total hip arthroplasty and, thus, jeopardize the overall success of the procedure. After Institutional Review Board approval, a retrospective review was undertaken to identify all patients undergoing revision total hip arthroplasty with anterior column augmentation through an extended direct anterior approach. Demographics and surgical details were collected, and subjects were followed for a 2-year minimum period to measure patient outcomes and to evaluate for the stability of construct fixation. A novel surgical procedure description was provided and supplemented with an illustrative case example. At 2 years post augmentation, patients had favorable functional outcomes with radiologic evidence of stable fixation. Proximal extension of the direct anterior approach to the hip can facilitate anterior column access and augmentation to improve stability of the hip reconstruction. This treatment may be an alternative to spanning constructs such as cup-cage constructs and custom implants, affording the potential for long-term biologic fixation. Further investigation into this technique is warranted. Copyright © 2016 Elsevier Inc. All rights reserved.

Computer-assisted total hip arthroplasty: coding the next generation of navigation systems for orthopedic surgery.

PubMed

Renkawitz, Tobias; Tingart, Markus; Grifka, Joachim; Sendtner, Ernst; Kalteis, Thomas

2009-09-01

This article outlines the scientific basis and a state-of-the-art application of computer-assisted orthopedic surgery in total hip arthroplasty (THA) and provides a future perspective on this technology. Computer-assisted orthopedic surgery in primary THA has the potential to couple 3D simulations with real-time evaluations of surgical performance, which has brought these developments from the research laboratory all the way to clinical use. Nonimage- or imageless-based navigation systems without the need for additional pre- or intra-operative image acquisition have stood the test to significantly reduce the variability in positioning the acetabular component and have shown precise measurement of leg length and offset changes during THA. More recently, computer-assisted orthopedic surgery systems have opened a new frontier for accurate surgical practice in minimally invasive, tissue-preserving THA. The future generation of imageless navigation systems will switch from simple measurement tasks to real navigation tools. These software algorithms will consider the cup and stem as components of a coupled biomechanical system, navigating the orthopedic surgeon to find an optimized complementary component orientation rather than target values intraoperatively, and are expected to have a high impact on clinical practice and postoperative functionality in modern THA.

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.

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.

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.

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.

Acetate templating on digital images is more accurate than computer-based templating for total hip arthroplasty.

PubMed

Petretta, Robert; Strelzow, Jason; Ohly, Nicholas E; Misur, Peter; Masri, Bassam A

2015-12-01

Templating is an important aspect of preoperative planning for total hip arthroplasty and can help determine the size and positioning of the prosthesis. Historically, templating has been performed using acetate templates over printed radiographs. As a result of the increasing use of digital imaging, surgeons now either obtain additional printed radiographs solely for templating purposes or use specialized digital templating software, both of which carry additional cost. The purposes of this study was to compare acetate templating of digitally calibrated images on an LCD monitor to digital templating in terms of (1) accuracy; (2) reproducibility; and (3) time efficiency. Acetate onlay templating was performed directly over digital radiographs on an LCD monitor and was compared with digital templating. Five separate observers participated in this study templating on 52 total hip arthroplasties. For the acetate templating, the digital images were magnified to the scaled reference on the templates provided by the manufacturer (ratio 1.2:1) before templating using a 25-mm marker as a reference. Both the acetate and digital templating results were then compared with the actual implanted components to determine accuracy. Interobserver and intraobserver variability was determined by an intraclass correlation coefficient. Observers recorded time to complete templating from the time of complete upload of patients' imaging onto the system to completion of templating. Both acetate and digital templates demonstrated moderate accuracy in predicting within one size of the eventual implanted acetabular cup (77% [199 of 260]; 70% [181 of 260], respectively; p = 0.050; 95% confidence interval [CI], 0.058-0.32), whereas acetate templating was better at predicting the femoral stem compared to digital templating (75% [195 of 260]; 60% [155 of 260], respectively; p < 0.001; 95% CI, 0.084-0.32). Acetate templating showed moderate to substantial interobserver agreement (cup intraclass correlation coefficient [ICC] = 0.55; 95% CI, 0.14-0.86; femoral ICC = 0.75; 95% CI, 0.39-0.95) and both methods showed almost perfect intraobserver agreement in reproducibility (acetate cup ICC = 0.82; 95% CI, 0.66-0.97; acetate femoral ICC = 0.86; 95% CI, 0.74-0.97; digital cup ICC = 0.82; 95% CI, 0.68-0.97; digital femoral ICC = 0.88; 95% CI, 0.77-1.0). Acetate templating could be performed more quickly (acetate mean 119 seconds; range, 37-220 seconds versus 154 seconds; range, 73-343 seconds; p < 0.001). Acetate onlay templating on digitally calibrated images can be a reliable substitute for digital templating using specialized software. It is quicker to perform and much less expensive. Hospitals and practices need not purchase expensive software, particularly at lower volume centers. Level III, diagnostic study.

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.

[A therapeutic effect analysis of femur first principle and combined anteversion technique during total hip arthroplasty].

PubMed

Wang, X Q; Wu, C S; Sun, S; Wang, J; Li, W; Zhang, W

2018-04-01

Objective: To investigate the situation of hip dislocation with the application of "femur first" principle and "combined anteversion technique" during total hip arthroplasty. Methods: A retrospective analysis has been done on the clinical data about 104 patients(133 hips)who were diagnosed as hip disease and were treated with total hip arthroplasty by the doctors from the Department of Joint Orthorpaedics of Shandong Provincial Hospital Affiliated to Shandong University from June 2014 to June 2016, and all the prostheses applied in the operation were cementless ones.Among them, 65 patients were males, 39 females and their age was 46.6 years (ranging from 23 to 76 years) .And 29 of them underwent bilateral hip operations and 75 unilateral ones.Seventy-six cases of aseptic necrosis of the femoral head in the terminal stage, 28 cases of hip dysplasia and osteoarthritis.Surgical approach: of all the operations, 103 hips were operated on with hardinge approach, 30 with posterolateral approach.During the operation, first of all, the femoral medullary cavity was broached and then the anteversion of intramedullary broacher was measured.After that, the anteversion of the acetabular cup was calculated as 37° minus the anteversion of the broacher, and the acetabular cup was implanted at that angle.The patients' prosthesis combined anteversion, range of motion of the hip joint, operation time, hemorrhage amount, and complications had been kept record.One, three, and six months respectively after the operation, all the patients received outpatient review, and took anteroposterior and lateral position X-ray examination.Harris hip score had been applied to evaluate their hip function before the operation and six months after the operation. Results: All the patients had been operated on smoothly, with the operation time of(57.6±14.5)minutes(36-115 minutes)and hemorrhage amount of (336.5±50.8)ml(180-620 ml). The operation finding showed that the combined anteversion by employing"femur first"principle and combined anteversion techniqueis was (36.6±6.8)°. Also, range of motion of the patients' hip conforms to the D'Lima criterion and no patients had experienced dislocation and some other serious complications.The follow-up ended at August 2017, which lasted for 12.2 months(6-18 months), and 88 cases(119 hips) were interviewed. The Harris hip score for the affected sides of the hip joints 6 months after the surgery was 94.6(86-100). Compared with the score of 29.8(12-43) before surgery, the t -test had proven its statistical significance( t =12.82, P =0.003). Conclusion: Based upon the "femoral first" principle and "combined anteversion technique" during total hip arthroplasty, these operations has been carried out well enough to meet the patients' needs of performing normal daily activities.

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.

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.

21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... component is intended to be fixed with bone cement. The acetabular component is intended for use without bone cement (§ 888.3027). (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP...

21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... component is intended to be fixed with bone cement. The acetabular component is intended for use without bone cement (§ 888.3027). (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP...

21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... component is intended to be fixed with bone cement. The acetabular component is intended for use without bone cement (§ 888.3027). (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP...

21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... component is intended to be fixed with bone cement. The acetabular component is intended for use without bone cement (§ 888.3027). (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP...

21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... component is intended to be fixed with bone cement. The acetabular component is intended for use without bone cement (§ 888.3027). (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP...

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.

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.

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.

[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

Ceramic-on-ceramic total hip arthroplasty in patients younger than 55 years.

PubMed

Shah, Roshan P; Scolaro, John A; Componovo, Roger; Garino, Jonathan P; Lee, Gwo-Chin

2014-12-01

To review the outcomes of 65 patients younger than 55 years who underwent uncemented total hip arthroplasty (THA) using third-generation ceramic-on-ceramic prostheses. Medical records of 30 men and 35 women (80 hips) aged 18 to 55 (mean, 39) years who underwent uncemented THA using third-generation ceramic-onceramic prostheses by a single surgeon were reviewed. 61 THAs used the Reflection cup with the Synergy stem (n=49), Spectron stem (n=7), or Anthology stem (n=5), and 19 THAs used the Trident cup with the Secur-Fit stem. Outcomes were assessed based on the UCLA Activity Score and Harris Hip Score, as well as radiolucency around the implants, malposition, and subsidence on radiographs. Patients were asked about their satisfaction with current activity level (yes/no), activity limitation (no limitation, musculoskeletal limitation, psychological impediments and lack of motivation, and pain or disability of the operative hip), and change in occupational activity level (same or similar, more active, and less active or disability). The mean follow-up period was 54 (range, 24-110) months. Six patients were excluded from the analysis owing to prosthetic failure secondary to ceramic liner fracture after falling (n=2), acetabular component loosening (n=1), intolerable squeak (n=1), periprosthetic fracture (n=1), and instability (n=1). The mean UCLA Activity Score improved from 4.0 (range, 1-10) to 7.7 (range, 2-10) [p<0.001], and the mean Harris Hip Score improved from 52.8 (range, 25-69) to 91.0 (range, 38-100) [p<0.001]. No hip had evidence of subsidence, loosening, or osteolysis. 52 (80%) patients were satisfied with their activity level; 28 (43%) patients reported no activity limitation; and 57 (88%) patients kept the same or similar occupation. Ceramic-on-ceramic THA achieved acceptable clinical and radiographic outcomes.

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.

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.

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.

Cement-in-cement acetabular revision with a constrained tripolar component.

PubMed

Leonidou, Andreas; Pagkalos, Joseph; Luscombe, Jonathan

2012-02-17

Dislocation of a total hip replacement (THR) is common following total hip arthroplasty (THA). When nonoperative management fails to maintain reduction, revision surgery is considered. The use of constrained acetabular liners has been extensively described. Complete removal of the old cement mantle during revision THA can be challenging and is associated with significant complications. Cement-in-cement revision is an established technique. However, the available clinical and experimental studies focus on femoral stem revision. The purpose of this study was to present a case of cement-in-cement acetabular revision with a constrained component for recurrent dislocations and to investigate the current best evidence for this technique. This article describes the case of a 74-year-old woman who underwent revision of a Charnley THR for recurrent low-energy dislocations. A tripolar constrained acetabular component was cemented over the primary cement mantle following removal of the original liner by reaming, roughening the surface, and thoroughly irrigating and drying the primary cement. Clinical and radiological results were good, with the Oxford Hip Score improving from 11 preoperatively to 24 at 6 months postoperatively. The good short-term results of this case and the current clinical and biomechanical data encourage the use of the cement-in-cement technique for acetabular revision. Careful irrigation, drying, and roughening of the primary surface are necessary. Copyright 2012, SLACK Incorporated.

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.

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.

Comparison of high‐intensity sound and mechanical vibration for cleaning porous titanium cylinders fabricated using selective laser melting

PubMed Central

Seiffert, Gary; Sutcliffe, Chris

2015-01-01

Abstract Orthopedic components, such as the acetabular cup in total hip joint replacement, can be fabricated using porous metals, such as titanium, and a number of processes, such as selective laser melting. The issue of how to effectively remove loose powder from the pores (residual powder) of such components has not been addressed in the literature. In this work, we investigated the feasibility of two processes, acoustic cleaning using high‐intensity sound inside acoustic horns and mechanical vibration, to remove residual titanium powder from selective laser melting‐fabricated cylinders. With acoustic cleaning, the amount of residual powder removed was not influenced by either the fundamental frequency of the horn used (75 vs. 230 Hz) or, for a given horn, the number of soundings (between 1 and 20). With mechanical vibration, the amount of residual powder removed was not influenced by the application time (10 vs. 20 s). Acoustic cleaning was found to be more reliable and effective in removal of residual powder than cleaning with mechanical vibration. It is concluded that acoustic cleaning using high‐intensity sound has significant potential for use in the final preparation stages of porous metal orthopedic components. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 117–123, 2017. PMID:26426906

Type of motion and lubricant in wear simulation of polyethylene acetabular cup.

PubMed

Saikko, V; Ahlroos, T

1999-01-01

The wear of ultra-high molecular weight polyethylene, the most commonly used bearing material in prosthetic joints, is often substantial, posing a significant clinical problem. For a long time, there has been a need for simple but still realistic wear test devices for prosthetic joint materials. The wear factors produced by earlier reciprocating and unidirectionally rotating wear test devices for polyethylene are typically two orders of magnitude too low, both in water and in serum lubrication. Wear is negligible even under multidirectional motion in water. A twelve-station, circularly translating pin-on-disc (CTPOD) device and a modification of the established biaxial rocking motion hip joint simulator were built. With these simple and inexpensive devices, and with the established three-axis hip joint simulator, realistic wear simulation was achieved. This was due to serum lubrication and to the fact that the direction of sliding constantly changed relative to the polyethylene specimen. The type and magnitude of load was found to be less important. The CTPOD tests showed that the subsurface brittle region, which results from gamma irradiation sterilization of polyethylene in air, has poor wear resistance. Phospholipid and soy protein lubrication resulted in unrealistic wear. The introduction of devices like CTPOD may boost wear studies, rendering them feasible without heavy investment.

Oxidation resistant peroxide cross-linked UHMWPE produced by blending and surface diffusion

NASA Astrophysics Data System (ADS)

Gul, Rizwan M.; Oral, Ebru; Muratoglu, Orhun K.

2014-06-01

Ultra-high molecular weight polyethylene (UHMWPE) has been widely used as acetabular cup in total hip replacement (THR) and tibial component in total knee replacement (TKR). Crosslinking of UHMWPE has been successful used to improve its wear performance leading to longer life of orthopedic implants. Crosslinking can be performed by radiation or organic peroxides. Peroxide crosslinking is a convenient process as it does not require specialized equipment and the level of crosslinking can be manipulated by changing the amount of peroxide added. However, there is concern about the long-term stability of these materials due to possible presence of by-products. Vitamin E has been successfully used to promote long-term oxidative stability of UHMWPE. In this study, UHMWPE has been crosslinked using organic peroxide in the presence of Vitamin E to produce an oxidation resistant peroxide crosslinked material. Crosslinking was performed both in bulk by mixing peroxide and resin, and only on the surface using diffusion of peroxides.The results show that UHMWPE can be crosslinked using organic peroxides in the presence of vitamin E by both methods. However, the level of crosslinking decreases with the increase in vitamin E content. The wear resistance increases with the increase in crosslink density, and oxidation resistance significantly increases due to the presence of vitamin E.

Friction measurement in a hip wear simulator.

PubMed

Saikko, Vesa

2016-05-01

A torque measurement system was added to a widely used hip wear simulator, the biaxial rocking motion device. With the rotary transducer, the frictional torque about the drive axis of the biaxial rocking motion mechanism was measured. The principle of measuring the torque about the vertical axis above the prosthetic joint, used earlier in commercial biaxial rocking motion simulators, was shown to sense only a minor part of the total frictional torque. With the present method, the total frictional torque of the prosthetic hip was measured. This was shown to consist of the torques about the vertical axis above the joint and about the leaning axis. Femoral heads made from different materials were run against conventional and crosslinked polyethylene acetabular cups in serum lubrication. Regarding the femoral head material and the type of polyethylene, there were no categorical differences in frictional torque with the exception of zirconia heads, with which the lowest values were obtained. Diamond-like carbon coating of the CoCr femoral head did not reduce friction. The friction factor was found to always decrease with increasing load. High wear could increase the frictional torque by 75%. With the present system, friction can be continuously recorded during long wear tests, so the effect of wear on friction with different prosthetic hips can be evaluated. © IMechE 2016.

Does haptic robot-assisted total hip arthroplasty better restore native acetabular and femoral anatomy?

PubMed

Tsai, Tsung-Yuan; Dimitriou, Dimitris; Li, Jing-Sheng; Kwon, Young-Min

2016-06-01

The objective was to evaluate whether total hip arthroplasty (THA) using haptic robot assistance restores hip geometry better than the free-hand technique. Twelve robot-assisted and 14 free-hand unilateral THA patients underwent CT scan for three-dimensional (3D) hip models. The anteversion, inclination and hip joint centre locations of the native and implanted hips in each patient were quantified and compared. Significant increase of combined anteversion by 19.1 ± 11.7° and 23.5 ± 23.6° and decrease of cup inclination by 16.5 ± 6.0° and 10.2 ± 6.8° were observed in the robot-assisted and the free-hand THAs, respectively. Less variation in the difference of the component orientations (max 11.1 vs 18.3°) and the femoral head centre (max 4.5 vs 6.3 mm) were found in the robot-assisted group. This study demonstrated that neither robot-assisted nor free-hand THAs had fully restored native hip geometry. However, the higher precision of the robot-assisted THA suggested that it has potential utility in restoring the native hip geometry. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

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.

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...

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.

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.

Socket position determines hip resurfacing 10-year survivorship.

PubMed

Amstutz, Harlan C; Le Duff, Michel J; Johnson, Alicia J

2012-11-01

Modern metal-on-metal hip resurfacing arthroplasty designs have been used for over a decade. Risk factors for short-term failure include small component size, large femoral head defects, low body mass index, older age, high level of sporting activity, and component design, and it is established there is a surgeon learning curve. Owing to failures with early surgical techniques, we developed a second-generation technique to address those failures. However, it is unclear whether the techniques affected the long-term risk factors. We (1) determined survivorship for hips implanted with the second-generation cementing technique; (2) identified the risk factors for failure in these patients; and (3) determined the effect of the dominant risk factors on the observed modes of failure. We retrospectively reviewed the first 200 hips (178 patients) implanted using our second-generation surgical technique, which consisted of improvements in cleaning and drying the femoral head before and during cement application. There were 129 men and 49 women. Component orientation and contact patch to rim distance were measured. We recorded the following modes of failure: femoral neck fracture, femoral component loosening, acetabular component loosening, wear, dislocation, and sepsis. The minimum followup was 25 months (mean, 106.5 months; range, 25-138 months). Twelve hips were revised. Kaplan-Meier survivorship was 98.0% at 5 years and 94.3% at 10 years. The only variable associated with revision was acetabular component position. Contact patch to rim distance was lower in hips that dislocated, were revised for wear, or were revised for acetabular loosening. The dominant modes of failure were related to component wear or acetabular component loosening. Acetabular component orientation, a factor within the surgeon's control, determines the long-term success of our current hip resurfacing techniques. Current techniques have changed the modes of failure from aseptic femoral failure to wear or loosening of the acetabular component. Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

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.

21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. 888.3320 Section 888.3320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic...

21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. 888.3320 Section 888.3320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic...

21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. 888.3320 Section 888.3320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic...

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

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.

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.

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.

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

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Comparison of high-intensity sound and mechanical vibration for cleaning porous titanium cylinders fabricated using selective laser melting.

PubMed

Seiffert, Gary; Hopkins, Carl; Sutcliffe, Chris

2017-01-01

Orthopedic components, such as the acetabular cup in total hip joint replacement, can be fabricated using porous metals, such as titanium, and a number of processes, such as selective laser melting. The issue of how to effectively remove loose powder from the pores (residual powder) of such components has not been addressed in the literature. In this work, we investigated the feasibility of two processes, acoustic cleaning using high-intensity sound inside acoustic horns and mechanical vibration, to remove residual titanium powder from selective laser melting-fabricated cylinders. With acoustic cleaning, the amount of residual powder removed was not influenced by either the fundamental frequency of the horn used (75 vs. 230 Hz) or, for a given horn, the number of soundings (between 1 and 20). With mechanical vibration, the amount of residual powder removed was not influenced by the application time (10 vs. 20 s). Acoustic cleaning was found to be more reliable and effective in removal of residual powder than cleaning with mechanical vibration. It is concluded that acoustic cleaning using high-intensity sound has significant potential for use in the final preparation stages of porous metal orthopedic components. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 117-123, 2017. © 2015 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc.

A complete-pelvis segmentation framework for image-free total hip arthroplasty (THA): methodology and clinical study.

PubMed

Xie, Weiguo; Franke, Jochen; Chen, Cheng; Grützner, Paul A; Schumann, Steffen; Nolte, Lutz-P; Zheng, Guoyan

2015-06-01

Complete-pelvis segmentation in antero-posterior pelvic radiographs is required to create a patient-specific three-dimensional pelvis model for surgical planning and postoperative assessment in image-free navigation of total hip arthroplasty. A fast and robust framework for accurately segmenting the complete pelvis is presented, consisting of two consecutive modules. In the first module, a three-stage method was developed to delineate the left hemi-pelvis based on statistical appearance and shape models. To handle complex pelvic structures, anatomy-specific information processing techniques were employed. As the input to the second module, the delineated left hemi-pelvis was then reflected about an estimated symmetry line of the radiograph to initialize the right hemi-pelvis segmentation. The right hemi-pelvis was segmented by the same three-stage method, Two experiments conducted on respectively 143 and 40 AP radiographs demonstrated a mean segmentation accuracy of 1.61±0.68 mm. A clinical study to investigate the postoperative assessment of acetabular cup orientations based on the proposed framework revealed an average accuracy of 1.2°±0.9° and 1.6°±1.4° for anteversion and inclination, respectively. Delineation of each radiograph costs less than one minute. Despite further validation needed, the preliminary results implied the underlying clinical applicability of the proposed framework for image-free THA. Copyright © 2014 John Wiley & Sons, Ltd.

[Innovation of characteristic medicinal cupping devices].

PubMed

Li, Jianping; Zhang, Hui; Yang, Jianmei; Xu, Xinchun; Niu, Yanxia; Cai, Jun

2015-08-01

To compare the differences in the characteristic medicinal cupping therapy between the traditional cupping device and the innovated cupping device. Fifty patients of neck and low back pain were selected. The self-comparison was adopted. The cupping therapy was applied to the acupoints located on the left or right side with the traditional cupping device and the innovated cupping device. The cupping sites were centered at bilateral Quyuan (SI 13) and Dachangshu (BL 25). The cups were retained for 10 min. The traditional cupping device was the glass with smooth border, 100mL. The innovated cupping device was the vacuum-sucking cup. The operative time, medicinal leakage, comfort and cupping marks were observed for the two different cupping devices. The operative time with the innovated medicinal cupping device was shorter obviously compared with the traditional one at Quyuan (SI 13) and Dachangshu (BL 25, both P<0. 05). The comfort with the innovated medicinal cupping device was remarkably improved as compared with the traditional one at the two acupoints (both P<0. 05). The medicinal leakage was similar between the two different devices during the cupping operation (both P>0. 05). The cupping marks with the innovated medicinal cupping device were much deeper than those with the traditional one after cupping therapy. The innovated cupping device is more convenent and comfortable in operation during the characteristic medicinal cupping therapy.

[Clinical value of cupping spot effect].

PubMed

Ji, Chang-Chun; Huang, Li-Ping; Yang, Gai-Qin; Zhao, Jing-Yu; Zou, Wei; Guo, Xiao-Chuan; Liu, Shao-Ming

2014-12-01

The cupping spot is considered as one kind of skin change due to cupping treatment. With literature regarding cupping spot, the influencing factors and value of cupping spot in clinical diagnosis and treatment were analyzed, which could make a further exploration on the action mechanism of cupping treatment. The literature showed that the formation of cupping spot was related with cupping temperature, pressure, cup-retaining time, cupping area, individual difference and health condition, etc; cupping spot had the ability to assist diagnosis, prevent disease, cure disease and evaluate clinical efficacy. Previous studies on cupping spot have already made some progress, and played a positive significance on finding cupping rule and studying its mechanism. However, the research for this area is still in the primary stage, which needed deeper study to reveal scientific connotations of cupping spot.

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

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.

Constant time worker thread allocation via configuration caching

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

Eichenberger, Alexandre E; O'Brien, John K. P.

Mechanisms are provided for allocating threads for execution of a parallel region of code. A request for allocation of worker threads to execute the parallel region of code is received from a master thread. Cached thread allocation information identifying prior thread allocations that have been performed for the master thread are accessed. Worker threads are allocated to the master thread based on the cached thread allocation information. The parallel region of code is executed using the allocated worker threads.

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.

Screw-Thread Standards for Federal Services, 1957. Handbook H28 (1957), Part 3

DTIC Science & Technology

1957-09-01

MOUNTING THREADS PHOTOGRAPHIC EQUIPMENT THREADS ISO METRIC THREADS; MISCELLANEOUS THREADS CLASS 5 INTERFERENCE-FIT THREADS, TRIAL STANDARD WRENCH...Bibliography on measurement of pitch diameter by means of wires 60 Appendix 14. Metric screw-thread standards 61 1. ISO thread profiles...61 2. Standard series for ISO metric threads 62 3. Designations for ISO metric threads 62 Tables Page Table XII. 1.—Basic

Modified Diet Recipes for Army Medical Facilities

DTIC Science & Technology

1983-10-20

Mashed 1/2 cup 100 Whole .1-2" diam. 100 Dried Beans 1/2 cup 100 Kidney Corn 1/3 cup 80 Macaroni 1/2 cup 70 Noodles 1/2 cup 80 Peas, green 1/2...5 mg sodium Na/R Bread or Toast Cereal, Cooked Na/R Potato, Sweet Na/R Mashed Na/R Whole Dried Beans Kidney Corn Macaroni Noodles Peas...cup Mashed - no milk 1/3 cup Baked-1/3 of 2-1/4 diam. Diced 1/3 cup Mashed - no milk 1/3 cup Beans, Kidney 1/3 cup Corn Macaroni Noodles

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

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.

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.

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.

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.

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.

Dedicated memory structure holding data for detecting available worker thread(s) and informing available worker thread(s) of task(s) to execute

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

Chiu, George L.; Eichenberger, Alexandre E.; O'Brien, John K. P.

The present disclosure relates generally to a dedicated memory structure (that is, hardware device) holding data for detecting available worker thread(s) and informing available worker thread(s) of task(s) to execute.

Spoon-to-Cup Fading as Treatment for Cup Drinking in a Child with Intestinal Failure

ERIC Educational Resources Information Center

Groff, Rebecca A.; Piazza, Cathleen C.; Zeleny, Jason R.; Dempsey, Jack R.

2011-01-01

We treated a child with intestinal failure who consumed solids on a spoon but not liquids from a cup. We used spoon-to-cup fading, which consisted of taping a spoon to a cup and then gradually moving the bowl of the spoon closer to the edge of the cup. Spoon-to-cup fading was effective for increasing consumption of liquids from a cup. (Contains 2…

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

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.

Experimental Investigation of the Robinson-Type Cup Anemometer

NASA Technical Reports Server (NTRS)

Brevoort, M J; Joyner, U T

1936-01-01

This report presents the results of wind tunnel tests on a Robinson-type anemometer. The investigation covered force measurements on individual cups, as well as static and dynamic torque measurements and calibrations on complete cup wheels. In the tests on individual cups 5 cup forms were used and in the measurements on complete cup wheels 4 cup wheels with 3 arm lengths for each cup wheel were tested. All the results are presented in graphical form.

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.

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.

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.

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.

Acoustic Performance of 3D Printed Nanocomposite Earmuff

PubMed Central

Ahmadi, Saeid; Nassiri, Parvin; Ghasemi, Ismaeil; Monazzam Ep, Mohammad R.

2016-01-01

Introduction: Hearing protection devices are one of the primary noise reduction tools in developing countries. This study is intended to produce and apply acrylonitrile butadiene styrene (ABS)/clay nanocomposites to fabricate a laboratory single cup earmuffs and then compare it with double cup and single cup pure ABS earmuffs in terms of noise attenuation performance and comfort. In addition, the noise attenuation performance of single cup pure ABS earmuffs is compared with double cup pure ABS earmuffs. Methods: ABS/nanoclay filament was fabricated using a twin screw extruder. A three dimensional (3D) printing machine and a 3D model of earcup, designed by solid work software, were applied to print single and double cup earmuffs using ABS/nanoclay composite and pure ABS filaments. Finally, using an acoustic test fixture, objective noise attenuation test was performed on three different types of earmuffs, including with and without nano material and a secondary cup. Moreover, earmuffs weight was measured as a comfort component. Results: Insertion loss and calculated noise reduction rating (NRR) of single cup ABS/nanoclay earmuffs (NRR=19.4 dB) and double cup pure ABS earmuffs (NRR=18.93 dB) were improved in comparison with single cup pure ABS earmuffs (NRR=15.7 dB). Additionally, both single cup earmuffs were significantly lighter than double cup earmuffs. Although single cup nano and double cup earmuffs had nearly the same attenuation performance, single cup nano earmuffs were 74 gr lighter than double cup earmuffs, so with reference to comfort, single cup nano earmuffs will probably be more acceptable. Conclusions: From this survey it might be concluded that, even though single cup ABS/nanoclay earmuffs was lighter than double cup pure ABS earmuffs, it had approximately more attenuation performance in comparison with double cup pure ABS earmuffs. Consequently, users are probably more prone to wear light- weight single cup ABS/nanoclay earmuffs as a result of improved comfort. In short, ABS/nanoclay composite can be considered a good choice in products with the necessity of high acoustic performance and low weight. PMID:26234977

Co-ordination of NDH and Cup proteins in CO2 uptake in cyanobacterium Synechocystis sp. PCC 6803.

PubMed

Han, Xunling; Sun, Nan; Xu, Min; Mi, Hualing

2017-06-01

High and low affinity CO2-uptake systems containing CupA (NDH-1MS) and CupB (NDH-1MS'), respectively, have been identified in Synechocystis sp. PCC 6803, but it is yet unknown how the complexes function in CO2 uptake. In this work, we found that deletion of cupB significantly lowered the growth of cells, and deletion of both cupA and cupB seriously suppressed the growth below pH 7.0 even under 3% CO2. The rate of photosynthetic oxygen evolution was decreased slightly by deletion of cupA but significantly by deletion of cupB and more severely by deletion of both cupA and cupB, especially in response to changed pH conditions under 3% CO2. Furthermore, we found that assembly of CupB into NDH-1MS' was dependent on NdhD4 and NdhF4. NDH-1MS' was not affected in the NDH-1MS-degradation mutant and NDH-1MS was not affected in the NDH-1MS'-degradation mutants, indicating the existence of independent CO2-uptake systems under high CO2 conditions. The light-induced proton gradient across thylakoid membranes was significantly inhibited in ndhD-deletion mutants, suggesting that NdhDs functions in proton pumping. The carbonic anhydrase activity was suppressed partly in the cupA- or cupB-deletion mutant but severely in the mutant with both cupA and cupB deletion, indicating that CupA and CupB function in conversion of CO2 to HCO3-. In turn, deletion of cup genes lowered the transthylakoid membrane proton gradient and deletion of ndhDs decreased the CO2 hydration. Our results suggest that NDH-1M provides an alkaline region to activate Cup proteins involved in CO2 uptake. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

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.

77 FR 2659 - Airworthiness Directives; Cessna Aircraft Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-19

...), and of the bearing cup for corrosion, turned cup, or clearance that exceeds limits, and repair as... cup for corrosion, turned cup, or clearance that exceeds limits, and repair if necessary; measuring... on the metal), and of the bearing cup for corrosion, turned cup, or clearance that exceeds limits...

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.

Cross-linked compared with historical polyethylene in THA: an 8-year clinical study.

PubMed

Geerdink, Carel H; Grimm, Bernd; Vencken, Wendy; Heyligers, Ide C; Tonino, Alphons J

2009-04-01

Wear particle-induced osteolysis is a major cause of aseptic loosening in THA. Increasing wear resistance of polyethylene (PE) occurs by increasing the cross-link density and early reports document low wear rates with such implants. To confirm longer-term reductions in wear we compared cross-linked polyethylene (irradiation in nitrogen, annealing) with historical polyethylene (irradiation in air) in a prospective, randomized clinical study involving 48 patients who underwent THAs with a minimum followup of 7 years (mean, 8 years; range, 7-9 years). The insert material was the only variable. The Harris hip score, radiographic signs of osteolysis, and polyethylene wear were recorded annually. Twenty-three historical and 17 moderately cross-linked polyethylene inserts were analyzed (five patients died, three were lost to followup). At 8 years, the wear rate was lower for cross-linked polyethylene (0.088 +/- 0.03 mm/year) than for the historical polyethylene (0.142 +/- 0.07 mm/year). This reduction (38%) did not diminish with time (33% at 5 years). Acetabular cyst formation was less frequent (39% versus 12%), affected fewer DeLee and Charnley zones (17% versus 4%), and was less severe for the cross-linked polyethylene. The only revision was for an aseptically loose cup in the historical polyethylene group. Moderately cross-linked polyethylene maintained its wear advantage with time and produced less osteolysis, showing no signs of aging at mid-term followup. Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Effect of inclination and anteversion angles on kinematics and contact mechanics of dual mobility hip implants.

PubMed

Gao, Yongchang; Chen, Zhenxian; Zhang, Zhifeng; Chen, Shibin; Jin, Zhongmin

2018-06-12

Steep inclination and excessive anteversion angles of acetabular cups could result in adverse edge-loading. This, in turn, increases contact pressure and impingement risk for traditional artificial hip joints. However, the influence of high inclination and anteversion angles on both the kinematics and contact mechanics of dual mobility hip implants has rarely been examined. This study focuses on investigating both the kinematics and contact mechanics of a dual mobility hip implant under different inclination and anteversion angles using a dynamic explicit finite element method developed in a previous study. The results showed that an inclination angle of both the back shell and liner ranging from 30° to 70° had little influence on the maximum contact pressure and the accumulated sliding distance of inner and outer surfaces of the liner under normal walking gait. The same results were obtained for an anteversion angle of the liner varying between -20° and +20°. However, when the anteversion angle of the liner was beyond this range, the contact between the femoral neck and the inner rim of the liner occurred. Consequently, this caused a relative rotation at the outer articulation. This suggests that both inclination and modest anteversion angles have little influence on the kinematics and contact mechanics of dual mobility hip implants. However, too excessive anteversion angle could result in a rotation for this kind of hip implant at both articulations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Thread selection according to power characteristics during context switching on compute nodes

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

Archer, Charles J.; Blocksome, Michael A.; Randles, Amanda E.

Methods, apparatus, and products are disclosed for thread selection during context switching on a plurality of compute nodes that includes: executing, by a compute node, an application using a plurality of threads of execution, including executing one or more of the threads of execution; selecting, by the compute node from a plurality of available threads of execution for the application, a next thread of execution in dependence upon power characteristics for each of the available threads; determining, by the compute node, whether criteria for a thread context switch are satisfied; and performing, by the compute node, the thread context switchmore » if the criteria for a thread context switch are satisfied, including executing the next thread of execution.« less

Thread selection according to predefined power characteristics during context switching on compute nodes

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

None, None

Methods, apparatus, and products are disclosed for thread selection during context switching on a plurality of compute nodes that includes: executing, by a compute node, an application using a plurality of threads of execution, including executing one or more of the threads of execution; selecting, by the compute node from a plurality of available threads of execution for the application, a next thread of execution in dependence upon power characteristics for each of the available threads; determining, by the compute node, whether criteria for a thread context switch are satisfied; and performing, by the compute node, the thread context switchmore » if the criteria for a thread context switch are satisfied, including executing the next thread of execution.« less

Cup tool use by squirrel monkeys.

PubMed

Buckmaster, Christine L; Hyde, Shellie A; Parker, Karen J; Lyons, David M

2015-12-01

Captive-born male and female squirrel monkeys spontaneously 'invented' a cup tool use technique to Contain (i.e., hold and control) food they reduced into fragments for consumption and to Contain water collected from a valve to drink. Food cup use was observed more frequently than water cup use. Observations indicate that 68% (n = 39/57) of monkeys in this population used a cup (a plastic slip cap) to Contain food, and a subset of these monkeys, 10% (n = 4/39), also used a cup to Contain water. Cup use was optional and did not replace, but supplemented, the hand/arm-to-mouth eating and direct valve drinking exhibited by all members of the population. Strategies monkeys used to bring food and cups together for food processing activity at preferred upper-level perching areas, in the arboreal-like environment in which they lived, provides evidence that monkeys may plan food processing activity with the cups. Specifically, prior to cup use monkeys obtained a cup first before food, or obtained food and a cup from the floor simultaneously, before transporting both items to upper-level perching areas. After food processing activity with cups monkeys rarely dropped the cups and more often placed the cups onto perching. Monkeys subsequently returned to use cups that they previously placed on perching after food processing activity. The latter behavior is consistent with the possibility that monkeys may keep cups at preferred perching sites for future food processing activity and merits experimental investigation. Reports of spontaneous tool use by squirrel monkeys are rare and this is the first report of population-level tool use. These findings offer insights into the cognitive abilities of squirrel monkeys and provide a new context for behavior studies with this genus and for comparative studies with other primates. © 2015 Wiley Periodicals, Inc.

Modified locking thread form for fastener

NASA Technical Reports Server (NTRS)

Roopnarine, (Inventor); Vranish, John D. (Inventor)

1998-01-01

A threaded fastener has a standard part with a standard thread form characterized by thread walls with a standard included angle, and a modified part complementary to the standard part having a modified thread form characterized by thread walls which are symmetrically inclined with a modified included angle that is different from the standard included angle of the standard part's thread walls, such that the threads of one part make pre-loaded edge contact with the thread walls of the other part. The thread form of the modified part can have an included angle that is greater, less, or compound as compared to the included angle of the standard part. The standard part may be a bolt and the modified part a nut, or vice versa. The modified thread form holds securely even under large vibrational forces, it permits bi-directional use of standard mating threads, is impervious to the build up of tolerances and can be manufactured with a wider range of tolerances without loss of functionality, and distributes loading stresses (per thread) in a manner that decreases the possibility of single thread failure.

Wet cupping therapy restores sympathovagal imbalances in cardiac rhythm.

PubMed

Arslan, Müzeyyen; Yeşilçam, Nesibe; Aydin, Duygu; Yüksel, Ramazan; Dane, Senol

2014-04-01

A recent study showed that cupping had therapeutic effects in rats with myocardial infarction and cardiac arrhythmias. The current studyaimed to investigate the possible useful effects of cupping therapy on cardiac rhythm in terms of heart rate variability (HRV). Forty healthy participants were included. Classic wet cupping therapy was applied on five points of the back. Recording electrocardiography (to determine HRV) was applied 1 hour before and 1 hour after cupping therapy. All HRV parameters increased after cupping therapy compared with before cupping therapy in healthy persons. These results indicate for the first time in humans that cupping might be cardioprotective. In this study, cupping therapy restored sympathovagal imbalances by stimulating the peripheral nervous system.

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.

[Progress of researches on the mechanism of cupping therapy].

PubMed

Cui, Shuai; Cui, Jin

2012-12-01

Cupping therapy of Chinese medicine is able to relieve a variety of diseases or clinical conditions, which results from the comprehensive effects of multiple types of stimulation exerted onto the regional acupoint areas. Among the stimuli, the negative pressure from cupping is one of the main factors inducing therapeutic effects. In the present paper, the authors review development of researches on the underlying mechanism of therapeutic effects of cupping-negative pressure from 1) the factor of intra-cup negative pressure; 2) influence of intra-cup negative pressure on cup-blackspot formation; 3) influence of cupping on regional blood vessels and blood flow; 4) effect of cupping on regional ultrastructure of the capillary in the raw-surface tissue; 5) effect of cupping-negative pressure on regional endothelial cells; and 6) biological effects of negative pressure drainage. Generally, cupping induced negative pressure can dilate local blood vessels to improve microcirculation, promote capillary endothelial cells repair, accelerate granulation and angiogenesis, etc., in the regional tissues, normalizing the patients' functional state at last.

Vacuum foil insulation system

DOEpatents

Hanson, John P.; Sabolcik, Rudolph E.; Svedberg, Robert C.

1976-11-16

In a multifoil thermal insulation package having a plurality of concentric cylindrical cups, means are provided for reducing heat loss from the penetration region which extends through the cups. At least one cup includes an integral skirt extending from one end of the cup to intersection with the penetration means. Assembly of the insulation package with the skirted cup is facilitated by splitting the cup to allow it to be opened up and fitted around the other cups during assembly.

An updated review of the efficacy of cupping therapy.

PubMed

Cao, Huijuan; Li, Xun; Liu, Jianping

2012-01-01

Since 1950, traditional Chinese medicine (TCM) cupping therapy has been applied as a formal modality in hospitals throughout China and elsewhere in the world. Based on a previous systematic literature review of clinical studies on cupping therapy, this study presents a thorough review of randomized controlled trials (RCTs) to evaluate the therapeutic effect of cupping therapy. Six databases were searched for articles published through 2010. RCTs on cupping therapy for various diseases were included. Studies on cupping therapy combined with other TCM treatments versus non-TCM therapies were excluded. 135 RCTs published from 1992 through 2010 were identified. The studies were generally of low methodological quality. Diseases for which cupping therapy was commonly applied were herpes zoster, facial paralysis (Bell palsy), cough and dyspnea, acne, lumbar disc herniation, and cervical spondylosis. Wet cupping was used in most trials, followed by retained cupping, moving cupping, and flash cupping. Meta-analysis showed cupping therapy combined with other TCM treatments was significantly superior to other treatments alone in increasing the number of cured patients with herpes zoster, facial paralysis, acne, and cervical spondylosis. No serious adverse effects were reported in the trials. Numerous RCTs on cupping therapy have been conducted and published during the past decades. This review showed that cupping has potential effect in the treatment of herpes zoster and other specific conditions. However, further rigorously designed trials on its use for other conditions are warranted.

78 FR 32990 - Special Local Regulation and Safety Zone; America's Cup Sailing Events, San Francisco, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-03

...] Special Local Regulation and Safety Zone; America's Cup Sailing Events, San Francisco, CA AGENCY: Coast... ``Louis Vuitton Cup, Red Bull Youth America's Cup and the 34th America's Cup'' regatta scheduled from July... associated with the 34th America's Cup sailing events taking place adjacent to the City of San Francisco...

Cutting thread at flexible endoscopy.

PubMed

Gong, F; Swain, P; Kadirkamanathan, S; Hepworth, C; Laufer, J; Shelton, J; Mills, T

1996-12-01

New thread-cutting techniques were developed for use at flexible endoscopy. A guillotine was designed to follow and cut thread at the endoscope tip. A new method was developed for guiding suture cutters. Efficacy of Nd: YAG laser cutting of threads was studied. Experimental and clinical experience with thread-cutting methods is presented. A 2.4 mm diameter flexible thread-cutting guillotine was constructed featuring two lateral holes with sharp edges through which sutures to be cut are passed. Standard suture cutters were guided by backloading thread through the cutters extracorporeally. A snare cutter was constructed to retrieve objects sewn to tissue. Efficacy and speed of Nd: YAG laser in cutting twelve different threads were studied. The guillotine cut thread faster (p < 0.05) than standard suture cutters. Backloading thread shortened time taken to cut thread (p < 0.001) compared with free-hand cutting. Nd: YAG laser was ineffective in cutting uncolored threads and slower than mechanical cutters. Results of thread cutting in clinical studies using sewing machine (n = 77 cutting episodes in 21 patients), in-vivo experiments (n = 156), and postsurgical cases (n = 15 over 15 years) are presented. New thread-cutting methods are described and their efficacy demonstrated in experimental and clinical studies.

[Impacts on skin blood flow under moving cupping along meridians in different directions].

PubMed

Tian, Yu-Ying; Wang, Guang-Jun; Huang, Tao; Jia, Shu-Yong; Zhang, Yu-Qin; Zhang, Wei-Bo

2013-03-01

To compare the impacts on skin blood flow between moving cupping following the meridian running direction and that against the running direction. JLG-2 meridian cupping drainage instru ment was used for moving cupping on the back along the Bladder Meridian running course in either single direction for 20 times. The cupping device was Bian stone cup, 44 mm in inner diameter, negative pressure from -0.03 to -0.04 MPa. PeriScan PIM II laser Doppler perfusion imager was used to observe the changes in skin blood flow on the running course of the Bladder Meridian with cup moved up and down and in the same region on the contralateral Bladder Meridian. Blood flow was measured before cupping, at the immediate time after cupping and 10 min after cupping separately. Fourteen healthy volunteers received the test. The measuring region was subdivided into a moving cupping area, an upstream area, a downstream area, a contralateral moving cupping area, a contralateral upstream area and a contralateral downstream area. The mean blood flow was calculated in each area. Blood flow was increased significantly in each area and was more apparently increased in the moving cupping area. In comparison of the changing rate of blood flow between cupping following the meridian running direction and that against the running direction, it was only found that the changing rate in the upstream area of moving cupping against the running direction was significantly higher than that following the running direction (P < 0.05). The differences were not statistically significant in comparison among the other areas. Additionally, the changing rates of blood flow in the upstream and downstream area of the Bladder Meridian were increased significantly as compared with the contralateral Bladder Meridian. The local effects are similar between moving cupping following the meridian running direction and that against the running direction. The abscopal effect of moving cupping against the running direction is superior to that following the running direction. It is suggested that the dual-directional moving cupping is applicable for the treatment of local disorders and the abscopal effect is better with moving cupping against the meridian running direction.

Developing and validating a sham cupping device.

PubMed

Lee, Myeong Soo; Kim, Jong-In; Kong, Jae Cheol; Lee, Dong-Hyo; Shin, Byung-Cheul

2010-12-01

The aims of this study were to develop a sham cupping device and to validate its use as a placebo control for healthy volunteers. A sham cupping device was developed by establishing a small hole to reduce the negative pressure after suction such that inner pressure could not be maintained in the cup. We enrolled 34 healthy participants to evaluate the validity of the sham cupping device as a placebo control. The participants were informed that they would receive either real or sham cupping and were asked which treatment they thought they had received. Other sensations and adverse events related to cupping therapy were investigated. 17 patients received real cupping therapy and 17 received sham cupping. The two groups felt similar sensations. There was a tendency for subjects to feel that real cupping created a stronger sensation than sham cupping (48.9±21.4 vs 33.3±20.3 on a 100mm visual analogue scale). There were only mild to moderate adverse events observed in both groups. We developed a new sham cupping device that seems to provide a credible control for real cupping therapy by producing little or no negative pressure. This conclusion was supported by a pilot study, but more rigorous research is warranted regarding the use of this device.

Tool Removes Coil-Spring Thread Inserts

NASA Technical Reports Server (NTRS)

Collins, Gerald J., Jr.; Swenson, Gary J.; Mcclellan, J. Scott

1991-01-01

Tool removes coil-spring thread inserts from threaded holes. Threads into hole, pries insert loose, grips insert, then pulls insert to thread it out of hole. Effects essentially reverse of insertion process to ease removal and avoid further damage to threaded inner surface of hole.

Clinical impact of the disposable ventouse iCup® versus a metallic vacuum cup: a multicenter randomized controlled trial.

PubMed

Equy, Véronique; David-Tchouda, Sandra; Dreyfus, Michel; Riethmuller, Didier; Vendittelli, Françoise; Cabaud, Victoire; Langer, Bruno; Margier, Jennifer; Bosson, Jean-Luc; Schaal, Jean-Patrick

2015-12-15

Assisted vaginal delivery by vacuum extraction is frequent. Metallic resterilizible metallic vacuum cups have been routinely used in France. In the last few years a new disposable semi-soft vacuum extraction cup, the iCup, has been introduced. Our objective was to compare maternal and new-born outcomes between this disposable cup and the commonly used Drapier-Faure metallic cup. This was a multicenter prospective randomized controlled open clinical trial performed in the maternity units of five university hospitals and one community hospital in France from October 2009 to February 2013. We included consecutive eligible women with a singleton gestation of at least 37 weeks who required vacuum assisted delivery. Women were randomized to vacuum extraction using the iCup or usual Drapier-Faure metallic cup. The primary outcome was a composite criterion including both the risk of cup dysfunction and the most frequent maternal and neonatal harms: the use of other instruments after attempted vacuum extraction, caesarean section after attempted vacuum extraction, three detachments of the cup, caput succedaneum, cephalohaematoma, episiotomy and perineal tears. 335 women were randomized to the disposable cup and 333 to extraction using the metallic cup. There was no significant difference between the two groups for the primary outcome. However, failed instrumental delivery was more frequent in the disposable cup group, mainly due to detachment: 35.6 % vs 7.1 %, p < 0.0001. Conversely, perineal tears were more frequent in the metallic cup group, especially third or fourth grade perineal tears: 1.7 % versus 5.0 %, p = 0.003. There were no significant differences between the two groups concerning post-partum haemorrhage, transfer to a neonatal intensive care unit (NICU) or serious adverse events. While the disposable cup had more detachments and extraction failures than the standard metallic cup, this innovative disposable device had the advantage of fewer perineal injuries. www.clinicaltrials.gov : NCT01058200 on Jan. 27 2010.

Thread gauge for measuring thread pitch diameters

DOEpatents

Brewster, A.L.

1985-11-19

A thread gauge which attaches to a vernier caliper to measure the thread pitch diameter of both externally threaded and internally threaded parts is disclosed. A pair of anvils are externally threaded with threads having the same pitch as those of the threaded part. Each anvil is mounted on a stem having a ball on which the anvil can rotate to properly mate with the parts to which the anvils are applied. The stems are detachably secured to the caliper blades by attachment collars having keyhole openings for receiving the stems and caliper blades. A set screw is used to secure each collar on its caliper blade. 2 figs.

Thread gauge for measuring thread pitch diameters

DOEpatents

Brewster, Albert L.

1985-01-01

A thread gauge which attaches to a vernier caliper to measure the thread pitch diameter of both externally threaded and internally threaded parts. A pair of anvils are externally threaded with threads having the same pitch as those of the threaded part. Each anvil is mounted on a stem having a ball on which the anvil can rotate to properly mate with the parts to which the anvils are applied. The stems are detachably secured to the caliper blades by attachment collars having keyhole openings for receiving the stems and caliper blades. A set screw is used to secure each collar on its caliper blade.

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

Evaluation of wet cupping therapy on the arterial and venous blood parameters in healthy Arabian horses

PubMed Central

Shawaf, Turke; El-Deeb, Wael; Hussen, Jamal; Hendi, Mahmoud; Al-Bulushi, Shahab

2018-01-01

Aim: Recently, the complementary therapies such as cupping and acupuncture are being used in veterinary medicine. This research was carried out to determine the effects of wet cupping therapy (Hijama) on the hematological and the biochemical parameters in the healthy Arabian horses for the first time. Materials and Methods: In this study, seven clinically healthy Arabian horses were randomly selected. Four points on the animal body were selected to perform the cupping therapy. Two points were selected at the back just behind the scapula on the left and right sides; another two points were located in the rump. Cups with 4 oz (125 ml) size with narrow mouths were used. A manual pump (sucking cups) was used to create the negative pressure within the cups during cupping. Arterial and venous blood parameters and serum cortisol concentration were measured before cupping and 3 days and 2, 4, and 8 weeks after cupping. Results: No significant differences were estimated in most hematological and biochemical parameters after cupping. A significant decrease in the concentration of serum cortisol was observed in 3 and 14 days after cupping. Conclusions: Cupping induced minor changes on the hematological and biochemical parameters in Arabian horses. This is the first trial on the effects of wet cupping therapy on the different parameters in Arabian horses, which would be useful for further investigations on the role of complementary therapies in horses. Our further studies will include different disease models.

An Updated Review of the Efficacy of Cupping Therapy

PubMed Central

Cao, Huijuan; Li, Xun; Liu, Jianping

2012-01-01

Background Since 1950, traditional Chinese medicine (TCM) cupping therapy has been applied as a formal modality in hospitals throughout China and elsewhere in the world. Based on a previous systematic literature review of clinical studies on cupping therapy, this study presents a thorough review of randomized controlled trials (RCTs) to evaluate the therapeutic effect of cupping therapy. Method Six databases were searched for articles published through 2010. RCTs on cupping therapy for various diseases were included. Studies on cupping therapy combined with other TCM treatments versus non-TCM therapies were excluded. Results 135 RCTs published from 1992 through 2010 were identified. The studies were generally of low methodological quality. Diseases for which cupping therapy was commonly applied were herpes zoster, facial paralysis (Bell palsy), cough and dyspnea, acne, lumbar disc herniation, and cervical spondylosis. Wet cupping was used in most trials, followed by retained cupping, moving cupping, and flash cupping. Meta-analysis showed cupping therapy combined with other TCM treatments was significantly superior to other treatments alone in increasing the number of cured patients with herpes zoster, facial paralysis, acne, and cervical spondylosis. No serious adverse effects were reported in the trials. Conclusions Numerous RCTs on cupping therapy have been conducted and published during the past decades. This review showed that cupping has potential effect in the treatment of herpes zoster and other specific conditions. However, further rigorously designed trials on its use for other conditions are warranted. PMID:22389674

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.

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.

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.

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.

Cup Implant Planning Based on 2-D/3-D Radiographic Pelvis Reconstruction-First Clinical Results.

PubMed

Schumann, Steffen; Sato, Yoshinobu; Nakanishi, Yuki; Yokota, Futoshi; Takao, Masaki; Sugano, Nobuhiko; Zheng, Guoyan

2015-11-01

In the following, we will present a newly developed X-ray calibration phantom and its integration for 2-D/3-D pelvis reconstruction and subsequent automatic cup planning. Two different planning strategies were applied and evaluated with clinical data. Two different cup planning methods were investigated: The first planning strategy is based on a combined pelvis and cup statistical atlas. Thereby, the pelvis part of the combined atlas is matched to the reconstructed pelvis model, resulting in an optimized cup planning. The second planning strategy analyzes the morphology of the reconstructed pelvis model to determine the best fitting cup implant. The first planning strategy was compared to 3-D CT-based planning. Digitally reconstructed radiographs of THA patients with differently severe pathologies were used to evaluate the accuracy of predicting the cup size and position. Within a discrepancy of one cup size, the size was correctly identified in 100% of the cases for Crowe type I datasets and in 77.8% of the cases for Crowe type II, III, and IV datasets. The second planning strategy was analyzed with respect to the eventually implanted cup size. In seven patients, the estimated cup diameter was correct within one cup size, while the estimation for the remaining five patients differed by two cup sizes. While both planning strategies showed the same prediction rate with a discrepancy of one cup size (87.5%), the prediction of the exact cup size was increased for the statistical atlas-based strategy (56%) in contrast to the anatomically driven approach (37.5%). The proposed approach demonstrated the clinical validity of using 2-D/3-D reconstruction technique for cup planning.

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.

Eat for Health

MedlinePlus

... pasta, or cereal Vegetables 4-5 1 cup raw leafy vegetables ½ cup cooked vegetables 6 oz vegetable juice Fruits 4-5 1 medium fruit ¼ cup dried fruit ½ cup fresh, frozen, or canned fruit ½ cup fruit juice Low-fat or fat-free milk and milk products 2- ...

New is the well-forgotten old: The use of dry cupping in musculoskeletal medicine.

PubMed

Rozenfeld, Evgeni; Kalichman, Leonid

2016-01-01

Cupping is an ancient technique used in treating pain and various disorders. Different techniques have been developed over time, however, applying a cup to create suction over a painful area, is common to all. Dry or fire cupping, used on the intact skin, leaves bluish circular hematomas. Recently, interest in cupping has re-emerged and subsequently, several studies have begun to investigate the mechanisms of cupping therapy. Mechanically, cupping increases blood circulation, whereas physiologically it activates the immune system and stimulates the mechanosensitive fibers, thus leading to a reduction in pain. There is initial scientific evidence that dry cupping is able to reduce musculoskeletal pain. Since cupping is an inexpensive, noninvasive and low-risk (if performed by a trained practitioner) therapeutic modality, we believe that it should be included in the arsenal of musculoskeletal medicine. It is essential to perform additional studies clarifying the biological mechanism and clinical effects of cupping. Copyright © 2015 Elsevier Ltd. All rights reserved.

78 FR 76815 - Steel Threaded Rod From India: Preliminary Affirmative Countervailing Duty Determination and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-19

... DEPARTMENT OF COMMERCE International Trade Administration [C-533-856] Steel Threaded Rod From... exporters of steel threaded rod from India. The period of investigation (``POI'') is January 1, 2012... this investigation is steel threaded rod. Steel threaded rod is certain threaded rod, bar, or studs, of...

Jacketed lamp bulb envelope

DOEpatents

MacLennan, Donald A.; Turner, Brian P.; Gitsevich, Aleksandr; Bass, Gary K.; Dolan, James T.; Kipling, Kent; Kirkpatrick, Douglas A.; Leng, Yongzhang; Levin, Izrail; Roy, Robert J.; Shanks, Bruce; Smith, Malcolm; Trimble, William C.; Tsai, Peter

2001-01-01

A jacketed lamp bulb envelope includes a ceramic cup having an open end and a partially closed end, the partially closed end defining an aperture, a lamp bulb positioned inside the ceramic cup abutting the aperture, and a reflective ceramic material at least partially covering a portion of the bulb not abutting the aperture. The reflective ceramic material may substantially fill an interior volume of the ceramic cup not occupied by the bulb. The ceramic cup may include a structural feature for aiding in alignment of the jacketed lamp bulb envelope in a lamp. The ceramic cup may include an external flange about a periphery thereof. One example of a jacketed lamp bulb envelope includes a ceramic cup having an open end and a closed end, a ceramic washer covering the open end of the ceramic cup, the washer defining an aperture therethrough, a lamp bulb positioned inside the ceramic cup abutting the aperture, and a reflective ceramic material filling an interior volume of the ceramic cup not occupied by the bulb. A method of packing a jacketed lamp bulb envelope of the type comprising a ceramic cup with a lamp bulb disposed therein includes the steps of filling the ceramic cup with a flowable slurry of reflective material, and applying centrifugal force to the cup to pack the reflective material therein.

Effect of head contact on the rim of the cup on the offset loading and torque in hip joint replacement.

PubMed

Liu, Feng; Williams, Sophie; Jin, Zhongmin; Fisher, John

2013-11-01

Head contact on the rim of the cup causes stress concentration and consequently increased wear. The head contact on the rim of the cup may in addition cause an offset load and torque on the cup. The head-rim contact resulting from microseparation or subluxation has been investigated. An analytical model has been developed to calculate the offset loading and resultant torque on the cup as a function of the translational displacement of the head under simplified loading condition of the hip joint at heel strike during a walking cycle. The magnitude of the torque on the cup was found to increase with the increasing translational displacement, larger diameter heads, eccentric cups, and the coefficient of friction of the contact. The effects of cup inclination, cup rim radius, and cup coverage angle on the magnitude of the torque were found to be relatively small with a maximum variation in the torque magnitude being lower than 20%. This study has shown an increased torque due to the head loading on the rim of the cup, and this may contribute to the incidence of cup loosening. Particularly, metal-on-metal hip joints with larger head diameters may produce the highest offset loading torque.

History of cupping (Hijama): a narrative review of literature.

PubMed

Qureshi, Naseem Akhtar; Ali, Gazzaffi Ibrahim; Abushanab, Tamer Shaban; El-Olemy, Ahmed Tawfik; Alqaed, Meshari Saleh; El-Subai, Ibrahim S; Al-Bedah, Abdullah M N

2017-05-01

Cupping (Hijama in Arabic) is an ancient, holistic method for the treatment of a variety of diseases. Though the exact origin of cupping therapy is a matter of controversy, its use has been documented in early Egyptian and Chinese medical practices. Diverse human civilizations have contributed to the historical development and continuation of cupping therapy. This narrative review describes the history of cupping, historical definitions, cupping instruments and uses of cupping therapy. Electronic searches of relevant databases (PubMed, Google Scholar and OvidSP) were conducted using keywords and Boolean operators. Manual searches and references of published articles and books were also conducted. A number of articles (N = 625) were retained for extensive review, and finally 83 articles were included in this paper. The historical descriptions of cupping therapy were found in ancient human civilizations of the Eastern and Western world. There were inconsistent data concerning the origin of cupping, definitions, instruments, procedures, definite advancements and research in Hijama over centuries. Cupping therapy fell out of favor in 17th and mid-18th centuries but recovered popularity in modern medicine. Currently, cupping therapy is used for health promotion, prophylaxis and treatment of a variety of diseases around the world. Cupping therapy with a good safety profile has a checkered history and is a well-recognized traditional method for managing medical conditions. Currently, the scope of cupping therapy is expanding, and a growing body of research is providing additional evidence-based data for the further advancement of cupping therapy in the treatment of a variety of diseases.

Online discussion groups for bulimia nervosa: an inductive approach to Internet-based communication between patients.

PubMed

Wesemann, Dorette; Grunwald, Martin

2008-09-01

Online discussion forums are often used by people with eating disorders. This study analyses 2,072 threads containing a total of 14,903 postings from an unmoderated German "prorecovery" forum for persons suffering from bulimia nervosa (www.ab-server.de) during the period from October 2004 to May 2006. The threads were inductively analyzed for underlying structural types, and the various types found were then analyzed for differences in temporal and quantitative parameters. Communication in the online discussion forum occurred in three types of thread: (1) problem-oriented threads (78.8% of threads), (2) communication-oriented threads (15.3% of threads), and (3) metacommunication threads (2.6% of threads). Metacommunication threads contained significantly more postings than problem-oriented and communication-oriented threads, and they were viewed significantly more often. Moreover, there are temporal differences between the structural types. Topics relating to active management of the disorder receive great attention in prorecovery forums. (c) 2008 by Wiley Periodicals, Inc.

Recommended Dietary Menus for Use in Operational and Research Saturation Diving

DTIC Science & Technology

1991-05-01

GMS MARGARINE-CORN-REG 1.0 TBSP 14.1 GMS CAKE-POUND 1.0 SLICE 33.0 GMS SNACK RAISINS-SEEDLESS 0.7 CUP 108.8 GMS NUTS - CASHEWS -DRY ROASTED 0.2 CUP 34.3...CUP 250.0 GMS TEA-INSTANT-PREP-UNSWEET 2.0 CUPS 474.0 GMS MARGARINE-CORN-REG 1.0 TBSP 14.1 GMS SNACK NUTS - CASHEWS -OIL ROASTED 0.3 CUP 39.0 GMS...GMS SNACK RAISINS-SEEDLESS 0.7 CUP 108.8 GMS NUTS - CASHEWS -DRY ROASTED 0.3 CUP 41.1 GMS NUTRIENT VALUES Kcalories 3694 Kc Carbohydrate 545.0 Gm Protein

Alternative medicine: an update on cupping therapy.

PubMed

Chen, B; Li, M-Y; Liu, P-D; Guo, Y; Chen, Z-L

2015-07-01

To know the research progress of cupping therapy all over the world, the authors analyze the research of cupping therapy in recent 5 years. It indicates that cupping therapy can be applied to extensive curable disease, but has poor clinical evidence. Some improvements in the mechanism research of cupping therapy have been made, but it needs further research. The adverse events of cupping therapy attract attention. The standardization of cupping therapy has emerged. © The Author 2014. Published by Oxford University Press on behalf of the Association of Physicians. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Menses cup evaluation study.

PubMed

Cheng, M; Kung, R; Hannah, M; Wilansky, D; Shime, J

1995-09-01

To determine whether the menses cup is well tolerated by menstruating women. Prospective descriptive clinical study. Normal human volunteers in an academic research environment. Fifty-one menstruating women recruited between June to December 1991. Each participant was provided with two menses cups and an instruction sheet. Baseline information, including age, occupation, martial status, parity, description of menstrual flow, and current method used to cope with menstrual flow was collected. Subjects were asked to describe their experience with the cup at 1-, 2-, 6-, and 12-month intervals. The proportion of women who found the cup acceptable. The cup was used by 51 subjects for a total of 159 cycles. Overall, 23 women (45%) found the cup an acceptable method for coping with menses. Among 29 (57%) women who used the cup for two or more cycles, 62% found it acceptable. The menses cup may be an acceptable method for some women for coping with menstrual flow.

Two years' outcome of thread lifting with absorbable barbed PDO threads: Innovative score for objective and subjective assessment.

PubMed

Ali, Yasser Helmy

2018-02-01

Thread-lifting rejuvenation procedures have evolved again, with the development of absorbable threads. Although they have gained popularity among plastic surgeons and dermatologists, very few articles have been written in literature about absorbable threads. This study aims to evaluate two years' outcome of thread lifting using absorbable barbed threads for facial rejuvenation. Prospective comparative stud both objectively and subjectively and follow-up assessment for 24 months. Thread lifting for face rejuvenation has significant long-lasting effects that include skin lifting from 3-10 mm and high degree of patients' satisfaction with less incidence rate of complications, about 4.8%. Augmented results are obtained when thread lifting is combined with other lifting and rejuvenation modalities. Significant facial rejuvenation is achieved by thread lifting and highly augmented results are observed when they are combined with Botox, fillers, and/or platelet rich plasma (PRP) rejuvenations.

Thread gauge for tapered threads

DOEpatents

Brewster, Albert L.

1994-01-11

The thread gauge permits the user to determine the pitch diameter of tapered threads at the intersection of the pitch cone and the end face of the object being measured. A pair of opposed anvils having lines of threads which match the configuration and taper of the threads on the part being measured are brought into meshing engagement with the threads on opposite sides of the part. The anvils are located linearly into their proper positions by stop fingers on the anvils that are brought into abutting engagement with the end face of the part. This places predetermined reference points of the pitch cone of the thread anvils in registration with corresponding points on the end face of the part being measured, resulting in an accurate determination of the pitch diameter at that location. The thread anvils can be arranged for measuring either internal or external threads.

Thread gauge for tapered threads

DOEpatents

Brewster, A.L.

1994-01-11

The thread gauge permits the user to determine the pitch diameter of tapered threads at the intersection of the pitch cone and the end face of the object being measured. A pair of opposed anvils having lines of threads which match the configuration and taper of the threads on the part being measured are brought into meshing engagement with the threads on opposite sides of the part. The anvils are located linearly into their proper positions by stop fingers on the anvils that are brought into abutting engagement with the end face of the part. This places predetermined reference points of the pitch cone of the thread anvils in registration with corresponding points on the end face of the part being measured, resulting in an accurate determination of the pitch diameter at that location. The thread anvils can be arranged for measuring either internal or external threads. 13 figures.

CNT coated thread micro-electro-mechanical system for finger proprioception sensing

NASA Astrophysics Data System (ADS)

Shafi, A. A.; Wicaksono, D. H. B.

2017-04-01

In this paper, we aim to fabricate cotton thread based sensor for proprioceptive application. Cotton threads are utilized as the structural component of flexible sensors. The thread is coated with multi-walled carbon nanotube (MWCNT) dispersion by using facile conventional dipping-drying method. The electrical characterization of the coated thread found that the resistance per meter of the coated thread decreased with increasing the number of dipping. The CNT coated thread sensor works based on piezoresistive theory in which the resistance of the coated thread changes when force is applied. This thread sensor is sewed on glove at the index finger between middle and proximal phalanx parts and the resistance change is measured upon grasping mechanism. The thread based microelectromechanical system (MEMS) enables the flexible sensor to easily fit perfectly on the finger joint and gives reliable response as proprioceptive sensing.

Biometry and spectral domain optical coherence tomography parameters in children with large cupping.

PubMed

Jung, Jong Jin; Baek, Seung-Hee; Kim, Ungsoo Samuel

2013-09-01

The purpose of this study is to investigate optic nerve head using spectral domain optical coherence tomography (SD-OCT) in children with large cupping. 111 eyes (4-10 years) were divided into three groups according to the cup to disc ratio: group 1, ≤0.3; group 2, 0.4-0.6; and group 3, ≥0.7. The rim area, disc area, average cup to disc ratio, vertical cup to disc ratio, and cup volume were investigated using SD-OCT (Cirrus HD-OCT, Carl Zeiss, Jena, Germany), and the axial length and anterior chamber depth (ACD) were measured by IOL master (IOL master 500, Carl Zeiss, Jena, Germany). Next, we compared ocular biometry and SD-OCT between the three groups. The mean age of group 1 was 6.48 ± 1.42 years, 7.00 ± 1.75 years in group 2, and 6.63 ± 1.82 years in group 3 (p = 0.370). A significant difference was seen in the spherical equivalent between the groups (p = 0.001). Group 2 had the most myopic refractive errors. As the cup to disc ratio increases, disc area, average cup to disc ratio, vertical cup to disc ratio, and cup volume increase significantly. When the results of ocular biometry and SD-OCT are adjusted for axial length, only disc area showed a significant correlation with cup to disc ratio (ACD: p = 0.473, rim area: p = 0.639, disc area: p = 0.005, and cup volume: p = 0.325). Axial length is the key factor determining disc size, which in turn is important for determining cup to disc ratio. Normal children with large cupping should be examined for axial length, myopic refractive errors, and disc size.

Design of internal screw thread measuring device based on the Three-Line method principle

NASA Astrophysics Data System (ADS)

Hu, Dachao; Chen, Jianguo

2010-08-01

In accordance with the principle of Three-Line, this paper analyze the correlation of every main parameter of internal screw thread, and then designed a device to measure the main parameters of internal screw thread. Internal thread parameters, such as the pitch diameter, thread angle and screw-pitch of common screw thread, terraced screw thread, zigzag screw thread were obtained through calculation and measurement. The practical applications have proved that this device is convenience to use, and the measurements have a high accuracy. Meanwhile, the application for the patent of invention has been accepted by the Patent Office (Filing number: 200710044081.5).

Is cupping blister harmful?-A proteomical analysis of blister fluid induced by cupping therapy and scald.

PubMed

Liu, Zhidan; Chen, Chunlan; Li, Xiaoyan; Zhao, Chuang; Li, Zunyuan; Liang, Wei; Lin, Yufang

2018-02-01

Cupping therapy has a long history in traditional medicine especially in Asian countries. It was controversial whether cupping induced blisters are beneficial to healing effects, and the formation and content in the blisters remain unexplored. We aimed to identify and compare the molecular components of the blister fluid from the cupping therapy and the scalds to explore the necessary of inducing cupping induced blisters. Fluid sample of blisters from fifteen patients receiving cupping therapy (Cupping group) and scald burns (Scald group) were collected in this study. Proteins from the blisters were separated by two-dimensional electrophoresis (2D-gel) and further analyzed by mass spectrometry. In addition, the changes in particular proteins were confirmed by Western blotting. The protein components are significantly different between blister from cupping therapy and scalds. The immune responses, oxidative stress and metabolic related proteins (Ig lambda-2 chain C regions, Ig gamma-1 chain C region, hemopexin, prdx2, calmodulin, succinyl-CoA ligase and tetranectin) were increased, whereas the hemoglobin subunit beta was decreased in the Cupping group compared with the Scald group. Cupping induced blisters contain several proteins which relate to the activation of certain immune pathways including anti-oxidation, anti-apoptosis, tissue repairing and metabolic regulation. This proteomic analysis may indicate a significant clue to the mechanism study of cupping. Copyright © 2017 Elsevier Ltd. All rights reserved.

77 FR 22706 - Special Local Regulation and Safety Zone; America's Cup Sailing Events, San Francisco, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-17

...] Special Local Regulation and Safety Zone; America's Cup Sailing Events, San Francisco, CA AGENCY: Coast... regulation and temporary safety zone proposed for those portions of the ``America's Cup World Series,'' the ``Louis Vuitton Cup'' challenger selection series, and the ``America's Cup Finals Match'' sailing regattas...

78 FR 36426 - Safety Zone; Queen's Cup; Lake Michigan; Milwaukee, WI

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-18

...-AA00 Safety Zone; Queen's Cup; Lake Michigan; Milwaukee, WI AGENCY: Coast Guard, DHS. ACTION: Temporary... Lake Michigan due to the 2013 Queen's Cup Race. This temporary safety zone is necessary to protect the... Queen's Cup Regatta. The Queen's Cup Regatta is a race from Milwaukee, WI to Ludington, MI that is...

Exploring Volumetrically Indexed Cups

ERIC Educational Resources Information Center

Jones, Dustin L.

2011-01-01

This article was inspired by a set of 12 cylindrical cups, which are volumetrically indexed; that is to say, the volume of cup "n" is equal to "n" times the volume of cup 1. Various sets of volumetrically indexed cylindrical cups are explored. I demonstrate how this children's toy is ripe for mathematical investigation, with connections to…

Effect of Seed Density on Splash Cup Seed Dispersal

NASA Astrophysics Data System (ADS)

Wigger, Patrick; Pepper, Rachel

2017-11-01

Splash cup plants are plants that utilize a small, mm-sized cup filled with seeds as a method of seed dispersal. The cup uses kinetic energy of an incident raindrop in order to project the seeds away from the plant up to 1 meter. The dispersal distance is important to ensure the offspring are not clustered too tightly to the parent plant. It has previously been found that a cup angle of 40 degrees to the horizontal is optimal for maximum dispersal of water from cups with no seeds. In this study we examine if the 40 degree cup is optimal for cups containing seeds with varying densities. We released uniform water drops above 5.0 mm 3D printed models of splash cups, using 1.0 mm plastic and glass microspheres of varying densities to simulate seeds. We observed the dispersal characteristics of each bead type by measuring the final seed locations after each splash, and by recording high speed video to determine the angle and velocity of the seeds as they exited the cup.

Retinal and anterior eye compartments derive from a common progenitor pool in the avian optic cup

PubMed Central

Venters, Sara J.; Cuenca, Paulina D.

2011-01-01

Purpose The optic cup is created through invagination of the optic vesicle. The morphogenetic rearrangement creates a double-layered cup, with a hinge (the Optic Cup Lip) where the epithelium bends back upon itself. Shortly after the optic cup forms, it is thought to be sub-divided into separate lineages: i) pigmented epithelium in the outer layer; ii) presumptive iris and ciliary body at the most anterior aspect of the inner layer; and iii) presumptive neural retina in the remainder of the inner layer. We test the native developmental potential of the anterior cup to determine if it normally contributes to the retina. Methods Vital dye and green fluorescent protein (GFP) expressing replication-incompetent retroviral vectors were used to label cells in the nascent optic cup and follow their direct progeny throughout development. Label was applied to either the optic cup lip (n=40), or to the domain just posterior to the lip (n=20). Retroviral labeling is a permanent lineage marker and enabled the analysis of advanced stages of development. Results Labeling within the optic cup gave rise to labeled progeny in the posterior optic cup that differentiated as neural retina (20 of 20). In contrast, labeling cells in the optic cup lip gave rise to progeny of labeled cells arrayed in a linear progression, from the lip into the neural retina (36 of 40). Label was retained in cells at the optic cup lip, regardless of age at examination. In older embryos, labeled progeny delaminated from the optic cup lip to differentiate as muscle of the pupillary margin. Conclusions The data show that the cells at the optic cup lip are a common progenitor population for pigmented epithelium, anterior eye tissues (ciliary body, iris, and pupillary muscle) and retinal neurons. The findings are supportive of an interpretation where the optic cup lip is a specialized niche containing a multipotent progenitor population. PMID:22219630

Thread angle dependency on flame spread shape over kenaf/polyester combined fabric

NASA Astrophysics Data System (ADS)

Azahari Razali, Mohd; Sapit, Azwan; Nizam Mohammed, Akmal; Nor Anuar Mohamad, Md; Nordin, Normayati; Sadikin, Azmahani; Faisal Hushim, Mohd; Jaat, Norrizam; Khalid, Amir

2017-09-01

Understanding flame spread behavior is crucial to Fire Safety Engineering. It is noted that the natural fiber exhibits different flame spread behavior than the one of the synthetic fiber. This different may influences the flame spread behavior over combined fabric. There is a research has been done to examined the flame spread behavior over kenaf/polyester fabric. It is seen that the flame spread shape is dependent on the thread angle dependency. However, the explanation of this phenomenon is not described in detail in that research. In this study, explanation about this phenomenon is given in detail. Results show that the flame spread shape is dependent on the position of synthetic thread. For thread angle, θ = 0°, the polyester thread is breaking when the flame approach to the thread and the kenaf thread tends to move to the breaking direction. This behavior produces flame to be ‘V’ shape. However, for thread angle, θ = 90°, the polyester thread melts while the kenaf thread decomposed and burned. At this angle, the distance between kenaf threads remains constant as flame approaches.

KSC-04PD-1316

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. In the Orbiter Processing Facility, Mike Bolt holds the Stanley Cup, won this year by the National Hockey Leagues Tampa Bay Lightning. Bolt is the Stanley Cup keeper. The cup was also briefly available for viewing by employees in the KSC Training Auditorium. Jay Feaster, general manager of the Tampa Bay Lightning, brought the cup to KSC while on a tour. The Stanley Cup weighs 35 pounds and is more than 100 years old. The Lightning will be added to the cup in September.

The effect of thread pattern upon implant osseointegration.

PubMed

Abuhussein, Heba; Pagni, Giorgio; Rebaudi, Alberto; Wang, Hom-Lay

2010-02-01

Implant design features such as macro- and micro-design may influence overall implant success. Limited information is currently available. Therefore, it is the purpose of this paper to examine these factors such as thread pitch, thread geometry, helix angle, thread depth and width as well as implant crestal module may affect implant stability. A literature search was conducted using MEDLINE to identify studies, from simulated laboratory models, animal, to human, related to this topic using the keywords of implant thread, implant macrodesign, thread pitch, thread geometry, helix angle, thread depth, thread width and implant crestal module. The results showed how thread geometry affects the distribution of stress forces around the implant. A decreased thread pitch may positively influence implant stability. Excess helix angles in spite of a faster insertion may jeopardize the ability of implants to sustain axial load. Deeper threads seem to have an important effect on the stabilization in poorer bone quality situations. The addition of threads or microthreads up to the crestal module of an implant might provide a potential positive contribution on bone-to to-implant contact as well as on the preservation of marginal bone; nonetheless this remains to be determined. Appraising the current literature on this subject and combining existing data to verify the presence of any association between the selected characteristics may be critical in the achievement of overall implant success.

Factitious panniculitis induced by cupping therapy.

PubMed

Moon, Suk-Ho; Han, Hyun-Ho; Rhie, Jong-Won

2011-11-01

Cupping therapy is an alternative medical procedure that has been widely performed in Asian countries to relieve pain. It is known that there is no complication to this therapy, so many non-health care professionals have performed this procedure. However, there have been few reports on complications, such as iron deficiency anemia, hemorrhagic bullae, kelloids, vasovagal syncope, and foreign body reactions. Masses associated with panniculitis induced by cupping are extremely rare, and they require a unique approach.A 56-year-old woman presented with a 10-month history of multiple masses in the posterior neck and right shoulder areas. The patient repeatedly attempted cupping therapy by herself, and multiple palpable masses developed in the posterior neck and right shoulder area where cupping therapy had been performed. The masses were enlarged by repeated cupping, and they decreased in size when cupping was stopped. Among all lesions, the 2 masses with tenderness were surgically excised. The remaining masses resolved after cupping therapy was ceased. When a patient with subcutaneous mass has a history of cupping or trace of cupping marks, panniculitis induced by cupping should be suspected. The lesion seems to spontaneously resolve unless they are repeatedly stimulated. However, surgical resection is considered in patients with infections or severe tenderness as a complication.

[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.

Differences in experiences of care between patients diagnosed with metastatic cancer of known and unknown primaries: mixed-method findings from the 2013 cancer patient experience survey in England

PubMed Central

Bracher, Mike; Drosdowsky, Allison; Richardson, Alison; Symons, John; Mileshkin, Linda; Schofield, Penny

2017-01-01

Objectives To explore differences in experiences of care reported in the Cancer Patient Experience Survey (CPES) between patients with cancer of unknown primary (CUP) and those with metastatic disease of known primary (non-CUP); to determine insights pertaining to the experiences of care for CUP respondents from free-text comments. Design Two separate, but related, studies, involving secondary analysis of existing data. Using frequency matching of CUP and non-CUP patients, statistical comparisons of responses to CPES questions were conducted. Free-text comments from CUP respondents were analysed thematically. Setting and participants The CPES questionnaire comprises 63 closed questions measuring 8 areas that relate to experience of care and 3 free-text questions. Questionnaires were mailed to all adult patients (aged ≥16 years) in England with cancer admitted to hospital between 1 September 2013 and 30 November 2013. Results Matched analysis of closed response items from 2992 patients found significant differences between CUP (n=1496) and non-CUP patients (n=1496): CUP patients were more likely to want more written information about their type of cancer and tests received, to receive their diagnosis from a general practitioner (GP) and have seen allied health professionals, but less likely to have understood explanations of their condition or had surgery. Freetext responses (n=3055) were coded into 17 categories and provided deeper insight regarding patient information and interactions with GPs. CPES data may include a preponderance of patients with favourable CUP subtypes and patients initially identified as CUP but whose primary was subsequently identified. Conclusions These are the first large-scale studies to explore the experiences of care of CUP patients. The significant differences identified between the experiences of CUP and non-CUP patients suggest CUP patients require more psychosocial support and specific interventions to manage diagnostic uncertainty and the multiple investigations many CUP patients face. Substantial limitations were identified with the CPES data, emphasising the need for prospective studies. PMID:28963312

Method for molding threads in graphite panels

DOEpatents

Short, W.W.; Spencer, C.

1994-11-29

A graphite panel with a hole having a damaged thread is repaired by drilling the hole to remove all of the thread and making a new hole of larger diameter. A bolt with a lubricated thread is placed in the new hole and the hole is packed with graphite cement to fill the hole and the thread on the bolt. The graphite cement is cured, and the bolt is unscrewed therefrom to leave a thread in the cement which is at least as strong as that of the original thread. 8 figures.

77 FR 4501 - Special Local Regulation and Safety Zone; America's Cup Sailing Events, San Francisco, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-30

...] RIN 1625-AA00; 1625-AA08 Special Local Regulation and Safety Zone; America's Cup Sailing Events, San... those portions of the ``America's Cup World Series,'' the ``Louis Vuitton Cup'' challenger selection series, and the ``America's Cup Finals Match'' sailing regattas that may be conducted in the waters of...

[Tripolar cups].

PubMed

Fink, B

2015-04-01

Tripolar cups can be separated into constrained and unconstrained dual-mobility cups. The latter show better survival and revision rates. The main problem is the polyethylene wear. Therefore modern types of polyethylene are used in these cups. The indications for dual-mobility cups are recurrent dislocation and situations where the risk of dislocation is increased. Georg Thieme Verlag KG Stuttgart · New York.

The measure method of internal screw thread and the measure device design

NASA Astrophysics Data System (ADS)

Hu, Dachao; Chen, Jianguo

2008-12-01

In accordance with the principle of Three-Line, this paper analyzed the correlation of every main parameter of internal screw thread, and then designed a device to measure the main parameters of internal screw thread. Basis on the measured value and corresponding formula calculation, we can get the internal thread parameters, such as the pitch diameter, thread angle and screw-pitch of common screw thread, terraced screw thread, zigzag screw thread and some else. The practical application has proved that this operation of this device is convenience, and the measured dates have a high accuracy. Meanwhile, the application of this device's patent of invention is accepted by the Patent Office. (The filing number: 200710044081.5)

Insertion tube methods and apparatus

DOEpatents

Casper, William L.; Clark, Don T.; Grover, Blair K.; Mathewson, Rodney O.; Seymour, Craig A.

2007-02-20

A drill string comprises a first drill string member having a male end; and a second drill string member having a female end configured to be joined to the male end of the first drill string member, the male end having a threaded portion including generally square threads, the male end having a non-threaded extension portion coaxial with the threaded portion, and the male end further having a bearing surface, the female end having a female threaded portion having corresponding female threads, the female end having a non-threaded extension portion coaxial with the female threaded portion, and the female end having a bearing surface. Installation methods, including methods of installing instrumented probes are also provided.

Subsurface drill string

DOEpatents

Casper, William L [Rigby, ID; Clark, Don T [Idaho Falls, ID; Grover, Blair K [Idaho Falls, ID; Mathewson, Rodney O [Idaho Falls, ID; Seymour, Craig A [Idaho Falls, ID

2008-10-07

A drill string comprises a first drill string member having a male end; and a second drill string member having a female end configured to be joined to the male end of the first drill string member, the male end having a threaded portion including generally square threads, the male end having a non-threaded extension portion coaxial with the threaded portion, and the male end further having a bearing surface, the female end having a female threaded portion having corresponding female threads, the female end having a non-threaded extension portion coaxial with the female threaded portion, and the female end having a bearing surface. Installation methods, including methods of installing instrumented probes are also provided.

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.

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

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.

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.

CMS event processing multi-core efficiency status

NASA Astrophysics Data System (ADS)

Jones, C. D.; CMS Collaboration

2017-10-01

In 2015, CMS was the first LHC experiment to begin using a multi-threaded framework for doing event processing. This new framework utilizes Intel’s Thread Building Block library to manage concurrency via a task based processing model. During the 2015 LHC run period, CMS only ran reconstruction jobs using multiple threads because only those jobs were sufficiently thread efficient. Recent work now allows simulation and digitization to be thread efficient. In addition, during 2015 the multi-threaded framework could run events in parallel but could only use one thread per event. Work done in 2016 now allows multiple threads to be used while processing one event. In this presentation we will show how these recent changes have improved CMS’s overall threading and memory efficiency and we will discuss work to be done to further increase those efficiencies.

Multi-threading: A new dimension to massively parallel scientific computation

NASA Astrophysics Data System (ADS)

Nielsen, Ida M. B.; Janssen, Curtis L.

2000-06-01

Multi-threading is becoming widely available for Unix-like operating systems, and the application of multi-threading opens new ways for performing parallel computations with greater efficiency. We here briefly discuss the principles of multi-threading and illustrate the application of multi-threading for a massively parallel direct four-index transformation of electron repulsion integrals. Finally, other potential applications of multi-threading in scientific computing are outlined.

Reusable and disposable cups: An energy-based evaluation

NASA Astrophysics Data System (ADS)

Hocking, Martin B.

1994-11-01

A group of five different types of reusable and disposable hot drink cups have been analyzed in detail with respect to their overall energy costs during fabrication and use. Electricity generating methods and efficiencies have been found to be key factors in the primary energy consumption for the washing of reusable cups and a less important factor in cup fabrication. In Canada or the United States, over 500 or more use cycles, reusable cups are found to have about the same or slightly more energy consumption, use for use, as moulded polystyrene foam cups used once and then discarded. For the same area paper cups used once and discarded are found to consume less fossil fuel energy per use than any of the other cup types examined. Details of this analysis, which could facilitate the comparative assessment of other scenarios, are presented.

Clinical research evidence of cupping therapy in China: a systematic literature review.

PubMed

Cao, Huijuan; Han, Mei; Li, Xun; Dong, Shangjuan; Shang, Yongmei; Wang, Qian; Xu, Shu; Liu, Jianping

2010-11-16

Though cupping therapy has been used in China for thousands of years, there has been no systematic summary of clinical research on it.This review is to evaluate the therapeutic effect of cupping therapy using evidence-based approach based on all available clinical studies. We included all clinical studies on cupping therapy for all kinds of diseases. We searched six electronic databases, all searches ended in December 2008. We extracted data on the type of cupping and type of diseases treated. 550 clinical studies were identified published between 1959 and 2008, including 73 randomized controlled trials (RCTs), 22 clinical controlled trials, 373 case series, and 82 case reports. Number of RCTs obviously increased during past decades, but the quality of the RCTs was generally poor according to the risk of bias of the Cochrane standard for important outcome within each trials. The diseases in which cupping was commonly employed included pain conditions, herpes zoster, cough or asthma, etc. Wet cupping was used in majority studies, followed by retained cupping, moving cupping, medicinal cupping, etc. 38 studies used combination of two types of cupping therapies. No serious adverse effects were reported in the studies. According to the above results, quality and quantity of RCTs on cupping therapy appears to be improved during the past 50 years in China, and majority of studies show potential benefit on pain conditions, herpes zoster and other diseases. However, further rigorous designed trials in relevant conditions are warranted to support their use in practice.

Cupping for Treating Pain: A Systematic Review

PubMed Central

Kim, Jong-In; Lee, Myeong Soo; Lee, Dong-Hyo; Boddy, Kate; Ernst, Edzard

2011-01-01

The objective of this study was to assess the evidence for or against the effectiveness of cupping as a treatment option for pain. Fourteen databases were searched. Randomized clinical trials (RCTs) testing cupping in patients with pain of any origin were considered. Trials using cupping with or without drawing blood were included, while trials comparing cupping with other treatments of unproven efficacy were excluded. Trials with cupping as concomitant treatment together with other treatments of unproven efficacy were excluded. Trials were also excluded if pain was not a central symptom of the condition. The selection of studies, data extraction and validation were performed independently by three reviewers. Seven RCTs met all the inclusion criteria. Two RCTs suggested significant pain reduction for cupping in low back pain compared with usual care (P < .01) and analgesia (P < .001). Another two RCTs also showed positive effects of cupping in cancer pain (P < .05) and trigeminal neuralgia (P < .01) compared with anticancer drugs and analgesics, respectively. Two RCTs reported favorable effects of cupping on pain in brachialgia compared with usual care (P = .03) or heat pad (P < .001). The other RCT failed to show superior effects of cupping on pain in herpes zoster compared with anti-viral medication (P = .065). Currently there are few RCTs testing the effectiveness of cupping in the management of pain. Most of the existing trials are of poor quality. Therefore, more rigorous studies are required before the effectiveness of cupping for the treatment of pain can be determined. PMID:19423657

Micro-wear features on unique 100-Mrad cups: two retrieved cups compared to hip simulator wear study.

PubMed

Yamamoto, Kengo; Masaoka, Toshinori; Manaka, Masakazu; Oonishi, Hironobu; Clarke, Ian; Shoji, Hiromu; Kawanabe, Keiichi; Imakiire, Atsuhiro

2004-04-01

We studied the micro-wear phenomena of unique, extensively cross-linked polyethylene cups (cross-linked with 1,000 kGy-irradiation) that had been used briefly in Japan. Two retrievals (at 15 years) came from the Japanese "SOM" hip system (implanted 1971-78). These were compared to a set of 0 kGy and 500-1,500 kGy cups run in our hip simulator. The polyethylene cups that had not been cross-linked had the greatest wear. The worn areas had a burnished appearance and were clearly separated from the unworn region by a distinct ridge-line. The worn areas had lost all machine tracks, showed a large amount of UHMWPE 'flow', and long PE fibrils. The associated surface rippling was degraded. These features were considered synonymous with severe polyethylene wear. In contrast, the worn areas in the very cross-linked cups had a visibly matte surface and no ridge-line. Micro-examination showed that the machine tracks were still present. Ripple formations were less obvious than in the cups that were not cross-linked, polyethylene surface fibrils were scarcer and all the fibrils were much smaller than in the cups that were not crosslinked. Our two retrieved cups and the simulator cups confirmed the greater wear-resistance of very cross-linked polyethylene. It should also be noted that the SOM cup design and processing were unique and differed greatly from that of modern polyethylene cups.

KSC-04PD-1319

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. Sitting in front of the open hatch into Discovery, which is in the Orbiter Processing Facility, Mike Bolt (left), NASAs Jack Legere (center front) and Jay Feaster (right) display the Stanley Cup. Feaster is general manager of the Tampa Bay Lightning, who won the cup in 2004, and Bolt is keeper of the cup. Legere is NASA Quality Assurance specialist for the Shuttle Program. The cup was also briefly available for viewing by employees in the KSC Training Auditorium. Feaster brought the cup to KSC while on a tour. The Stanley Cup weighs 35 pounds and is more than 100 years old. The Lightning will be added to the cup in September.

Mathematical Analysis of the Effect of Rotor Geometry on Cup Anemometer Response

PubMed Central

Sanz-Andrés, Ángel; Sorribes-Palmer, Félix

2014-01-01

The calibration coefficients of two commercial anemometers equipped with different rotors were studied. The rotor cups had the same conical shape, while the size and distance to the rotation axis varied. The analysis was based on the 2-cup positions analytical model, derived using perturbation methods to include second-order effects such as pressure distribution along the rotating cups and friction. The comparison with the experimental data indicates a nonuniform distribution of aerodynamic forces on the rotating cups, with higher forces closer to the rotating axis. The 2-cup analytical model is proven to be accurate enough to study the effect of complex forces on cup anemometer performance. PMID:25110735

Multiple data sets and modelling choices in a comparative LCA of disposable beverage cups.

PubMed

van der Harst, Eugenie; Potting, José; Kroeze, Carolien

2014-10-01

This study used multiple data sets and modelling choices in an environmental life cycle assessment (LCA) to compare typical disposable beverage cups made from polystyrene (PS), polylactic acid (PLA; bioplastic) and paper lined with bioplastic (biopaper). Incineration and recycling were considered as waste processing options, and for the PLA and biopaper cup also composting and anaerobic digestion. Multiple data sets and modelling choices were systematically used to calculate average results and the spread in results for each disposable cup in eleven impact categories. The LCA results of all combinations of data sets and modelling choices consistently identify three processes that dominate the environmental impact: (1) production of the cup's basic material (PS, PLA, biopaper), (2) cup manufacturing, and (3) waste processing. The large spread in results for impact categories strongly overlaps among the cups, however, and therefore does not allow a preference for one type of cup material. Comparison of the individual waste treatment options suggests some cautious preferences. The average waste treatment results indicate that recycling is the preferred option for PLA cups, followed by anaerobic digestion and incineration. Recycling is slightly preferred over incineration for the biopaper cups. There is no preferred waste treatment option for the PS cups. Taking into account the spread in waste treatment results for all cups, however, none of these preferences for waste processing options can be justified. The only exception is composting, which is least preferred for both PLA and biopaper cups. Our study illustrates that using multiple data sets and modelling choices can lead to considerable spread in LCA results. This makes comparing products more complex, but the outcomes more robust. Copyright © 2014 Elsevier B.V. All rights reserved.