Science.gov

Sample records for metal-on-metal resurfacing hip

  1. Metal-on-Metal Hip Resurfacing Arthroplasty

    PubMed Central

    Sehatzadeh, S; Kaulback, K; Levin, L

    2012-01-01

    Background Metal-on-metal (MOM) hip resurfacing arthroplasty (HRA) is in clinical use as an appropriate alternative to total hip arthroplasty in young patients. In this technique, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the acetabulum. Objectives The primary objective of this analysis was to compare the revision rates of MOM HRA using different implants with the benchmark set by the National Institute of Clinical Excellence (NICE). The secondary objective of this analysis was to review the literature regarding adverse biological effects associated with implant material. Review Methods A literature search was performed on February 13, 2012, to identify studies published from January 1, 2009, to February 13, 2012. Results The revision rates for MOM HRA using 6 different implants were reviewed. The revision rates for MOM HRA with 3 implants met the NICE criteria, i.e., a revision rate of 10% or less at 10 years. Two implants had short-term follow-ups and MOM HRA with one of the implants failed to meet the NICE criteria. Adverse tissue reactions resulting in failure of the implants have been reported by several studies. With a better understanding of the factors that influence the wear rate of the implants, adverse tissue reactions and subsequent implant failure can be minimized. Many authors have suggested that patient selection and surgical technique affect the wear rate and the risk of tissue reactions. The biological effects of high metal ion levels in the blood and urine of patients with MOM HRA implants are not known. Studies have shown an increase in chromosomal aberrations in patients with MOM articulations, but the clinical implications and long-term consequences of this increase are still unknown. Epidemiological studies have shown that patients with MOM HRA implants did not have an overall increase in mortality or risk of cancer. There is insufficient clinical data to confirm the

  2. Metal-on-Metal Total Hip Resurfacing Arthroplasty

    PubMed Central

    2006-01-01

    Executive Summary Objective The objective of this review was to assess the safety and effectiveness of metal on metal (MOM) hip resurfacing arthroplasty for young patients compared with that of total hip replacement (THR) in the same population. Clinical Need Total hip replacement has proved to be very effective for late middle-aged and elderly patients with severe degenerative diseases of the hips. As indications for THR began to include younger patients and those with a more active life style, the longevity of the implant became a concern. Evidence suggests that these patients experience relatively higher rates of early implant failure and the need for revision. The Swedish hip registry, for example, has demonstrated a survival rate in excess of 80% at 20 years for those aged over 65 years, whereas this figure was 33% by 16 years in those aged under 55 years. Hip resurfacing arthroplasty is a bone-conserving alternative to THR that restores normal joint biomechanics and load transfer. The technique has been used around the world for more than 10 years, specifically in the United Kingdom and other European countries. The Technology Metal-on-metal hip resurfacing arthroplasty is an alternative procedure to conventional THR in younger patients. Hip resurfacing arthroplasty is less invasive than THR and addresses the problem of preserving femoral bone stock at the initial operation. This means that future hip revisions are possible with THR if the initial MOM arthroplasty becomes less effective with time in these younger patients. The procedure involves the removal and replacement of the surface of the femoral head with a hollow metal hemisphere, which fits into a metal acetabular cup. Hip resurfacing arthroplasty is a technically more demanding procedure than is conventional THR. In hip resurfacing, the femoral head is retained, which makes it much more difficult to access the acetabular cup. However, hip resurfacing arthroplasty has several advantages over a

  3. Retrieval analysis of 240 metal-on-metal hip components, comparing modular total hip replacement with hip resurfacing.

    PubMed

    Matthies, A; Underwood, R; Cann, P; Ilo, K; Nawaz, Z; Skinner, J; Hart, A J

    2011-03-01

    This study compared component wear rates and pre-revision blood metal ions levels in two groups of failed metal-on-metal hip arthroplasties: hip resurfacing and modular total hip replacement (THR). There was no significant difference in the median rate of linear wear between the groups for both acetabular (p = 0.4633) and femoral (p = 0.0872) components. There was also no significant difference in the median linear wear rates when failed hip resurfacing and modular THR hips of the same type (ASR and Birmingham hip resurfacing (BHR)) were compared. Unlike other studies of well-functioning hips, there was no significant difference in pre-revision blood metal ion levels between hip resurfacing and modular THR. Edge loading was common in both groups, but more common in the resurfacing group (67%) than in the modular group (57%). However, this was not significant (p = 0.3479). We attribute this difference to retention of the neck in resurfacing of the hip, leading to impingement-type edge loading. This was supported by visual evidence of impingement on the femur. These findings show that failed metal-on-metal hip resurfacing and modular THRs have similar component wear rates and are both associated with raised pre-revision blood levels of metal ions. PMID:21357950

  4. Microseparation, fluid pressure and flow in failures of metal-on-metal hip resurfacing arthroplasties

    PubMed Central

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

    2012-01-01

    Objectives Metal-on-metal (MoM) hip resurfacing was introduced into clinical practice because it was perceived to be a better alternative to conventional total hip replacement for young and active patients. However, an increasing number of reports of complications have arisen focusing on design and orientation of the components, the generation of metallic wear particles and serum levels of metallic ions. The procedure introduced a combination of two elements: large-dimension components and hard abrasive particles of metal wear. The objective of our study was to investigate the theory that microseparation of the articular surfaces draws in a high volume of bursal fluid and its contents into the articulation, and at relocation under load would generate high pressures of fluid ejection, resulting in an abrasive water jet. Methods This theoretical concept using MoM resurfacing components (head diameter 55 mm) was modelled mathematically and confirmed experimentally using a material-testing machine that pushed the head into the cup at a rate of 1000 mm/min until fully engaged. Results The mathematical model showed the pattern but not the force of fluid ejection, the highest pressures were expected when the separation of the components was only a fraction of one millimetre. The experimental work confirmed the results; with the mean peak ejection pressure of 43 763 N/m2 equivalent to 306 mmHg or 5 psi. Conclusions The mechanical effect of the high-pressure abrasive water jet is the likely cause of the spectrum of complications reported with metal-on-metal resurfacing. Investigating serum levels of metallic elements may not be the best method for assessing the local mechanical effects of the abrasive water jet. PMID:23610667

  5. Mortality rates at 10 years after metal-on-metal hip resurfacing compared with total hip replacement in England: retrospective cohort analysis of hospital episode statistics

    PubMed Central

    Kendal, Adrian R; Prieto-Alhambra, Daniel; Arden, Nigel K; Judge, Andrew

    2013-01-01

    Objectives To compare 10 year mortality rates among patients undergoing metal-on-metal hip resurfacing and total hip replacement in England. Design Retrospective cohort study. Setting English hospital episode statistics database linked to mortality records from the Office for National Statistics. Population All adults who underwent primary elective hip replacement for osteoarthritis from April 1999 to March 2012. The exposure of interest was prosthesis type: cemented total hip replacement, uncemented total hip replacement, and metal-on-metal hip resurfacing. Confounding variables included age, sex, Charlson comorbidity index, rurality, area deprivation, surgical volume, and year of operation. Main outcome measures All cause mortality. Propensity score matching was used to minimise confounding by indication. Kaplan-Meier plots estimated the probability of survival up to 10 years after surgery. Multilevel Cox regression modelling, stratified on matched sets, described the association between prosthesis type and time to death, accounting for variation across hospital trusts. Results 7437 patients undergoing metal-on-metal hip resurfacing were matched to 22 311 undergoing cemented total hip replacement; 8101 patients undergoing metal-on-metal hip resurfacing were matched to 24 303 undergoing uncemented total hip replacement. 10 year rates of cumulative mortality were 271 (3.6%) for metal-on-metal hip resurfacing versus 1363 (6.1%) for cemented total hip replacement, and 239 (3.0%) for metal-on-metal hip resurfacing versus 999 (4.1%) for uncemented total hip replacement. Patients undergoing metal-on-metal hip resurfacing had an increased survival probability (hazard ratio 0.51 (95% confidence interval 0.45 to 0.59) for cemented hip replacement; 0.55 (0.47 to 0.65) for uncemented hip replacement). There was no evidence for an interaction with age or sex. Conclusions Patients with hip osteoarthritis undergoing metal-on-metal hip resurfacing have reduced mortality in

  6. Fast growing pseudotumour in a hairdresser after metal-on-metal hip resurfacing: a case report.

    PubMed

    Cadossi, M; Chiarello, E; Savarino, L; Mazzotti, A; Tedesco, G; Greco, M; Giannini, S

    2014-01-01

    A 44-year-old female hairdresser who underwent metal-on-metal hip resurfacing (MOMHR) for hip osteoarthritis developed a benign pelvic pseudotumour. Elevated levels of chromium and cobalt ions were detected in the blood. Patch testing after pseudotumor formation, showed positive skin reactions to cobalt and nickel. Marked hypereosinophilia was noted, as well as the presence of eosinophils in the pseudotumor mass. A revision to a ceramic-on-ceramic implant was performed. Radiographs showed no implant loosening or bone resorption. We hypothesized that a steep cup positioning as well as hypersensitivity response to the metal nanoparticles and ion release may have induced pseudotumour development. Currently there is no evidence that negative patch testing reduces the probability to develop an adverse reaction to metal debris therefore we suggest to carefully investigate patient medical history regarding occupation exposure and daily contact with jewellery, beauty and cleaning products before implanting MOMHR. The main challenge is to identify a sensitive patient candidate to MOMHR never suspected to be. PMID:24825038

  7. Survivorship of standard versus modified posterior surgical approaches in metal-on-metal hip resurfacing

    PubMed Central

    M. Takamura, K.; Maher, P.; Nath, T.; Su, E. P.

    2014-01-01

    Objectives Metal-on-metal hip resurfacing (MOMHR) is available as an alternative option for younger, more active patients. There are failure modes that are unique to MOMHR, which include loosening of the femoral head and fractures of the femoral neck. Previous studies have speculated that changes in the vascularity of the femoral head may contribute to these failure modes. This study compares the survivorship between the standard posterior approach (SPA) and modified posterior approach (MPA) in MOMHR. Methods A retrospective clinical outcomes study was performed examining 351 hips (279 male, 72 female) replaced with Birmingham Hip Resurfacing (BHR, Smith and Nephew, Memphis, Tennessee) in 313 patients with a pre-operative diagnosis of osteoarthritis. The mean follow-up period for the SPA group was 2.8 years (0.1 to 6.1) and for the MPA, 2.2 years (0.03 to 5.2); this difference in follow-up period was statistically significant (p < 0.01). Survival analysis was completed using the Kaplan–Meier method. Results At four years, the Kaplan–Meier survival curve for the SPA was 97.2% and 99.4% for the MPA; this was statistically significant (log-rank; p = 0.036). There were eight failures in the SPA and two in the MPA. There was a 3.5% incidence of femoral head collapse or loosening in the SPA and 0.4% in the MPA, which represented a significant difference (p = 0.041). There was a 1.7% incidence of fractures of the femoral neck in the SPA and none in the MPA (p = 0.108). Conclusion This study found a significant difference in survivorship at four years between the SPA and the MPA (p = 0.036). The clinical outcomes of this study suggest that preserving the vascularity of the femoral neck by using the MPA results in fewer vascular-related failures in MOMHRs. Cite this article: Bone Joint Res 2014;3:150–4 PMID:24842931

  8. Metal ion levels and functional results after either resurfacing hip arthroplasty or conventional metal-on-metal hip arthroplasty

    PubMed Central

    2011-01-01

    Background Modern metal-on-metal hip resurfacing was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potentially increased metal ion release. Patients and methods 71 patients (< 65 years old) were randomly assigned to receive either a resurfacing (R) hip arthroplasty (n = 38) or a conventional metal-on-metal (C) hip arthroplasty (n = 33). Functional outcomes were assessed preoperatively and at 6, 12, and 24 months. Cobalt and chromium blood levels were analyzed preoperatively and at 3, 6, 12, and 24 months. Results All functional outcome scores improved for both groups. At 12 and 24 months, the median UCLA activity score was 8 in the R patients and 7 in the C patients (p < 0.05). At 24 months, OHS was median 16 in C patients and 13 in R patients (p < 0.05). However, in spite of randomization, UCLA scores also appeared to be higher in R patients at baseline. Satisfaction was similar in both groups at 24 months. Cobalt concentrations were statistically significantly higher for R patients only at 3 and 6 months. Chromium levels remained significantly higher for R patients until 24 months. No pseudotumors were encountered in either group. One R patient was revised for early aseptic loosening and in 2 C patients a cup insert was exchanged for recurrent dislocation. Interpretation R patients scored higher on UCLA, OHS, and satisfaction at some time points; however, as for the UCLA, preoperative levels were already in favor of R. The differences, although statistically significant, were of minor clinical importance. Chromium blood levels were statistically significantly higher for R patients at all follow-up measurements, whereas for cobalt this was only observed up to 6 months. The true value of resurfacing hip arthroplasty over conventional metal-on-metal hip arthroplasty will be determined by longer follow-up and a possible shift of balance between their

  9. Effect of simplifications of bone and components inclination on the elastohydrodynamic lubrication modeling of metal-on-metal hip resurfacing prosthesis.

    PubMed

    Meng, Qingen; Liu, Feng; Fisher, John; Jin, Zhongmin

    2013-05-01

    It is important to study the lubrication mechanism of metal-on-metal hip resurfacing prosthesis in order to understand its overall tribological performance, thereby minimize the wear particles. Previous elastohydrodynamic lubrication studies of metal-on-metal hip resurfacing prosthesis neglected the effects of the orientations of the cup and head. Simplified pelvic and femoral bone models were also adopted for the previous studies. These simplifications may lead to unrealistic predictions. For the first time, an elastohydrodynamic lubrication model was developed and solved for a full metal-on-metal hip resurfacing arthroplasty. The effects of the orientations of components and the realistic bones on the lubrication performance of metal-on-metal hip resurfacing prosthesis were investigated by comparing the full model with simplified models. It was found that the orientation of the head played a very important role in the prediction of pressure distributions and film profiles of the metal-on-metal hip resurfacing prosthesis. The inclination of the hemispherical cup up to 45° had no appreciable effect on the lubrication performance of the metal-on-metal hip resurfacing prosthesis. Moreover, the combined effect of material properties and structures of bones was negligible. Future studies should focus on higher inclination angles, smaller coverage angle and microseparation related to the occurrences of edge loading.

  10. Combined Vascular and Orthopaedic Approach for a Pseudotumor Causing Deep Vein Thrombosis after Metal-on-Metal Hip Resurfacing Arthroplasty

    PubMed Central

    Abdel-Hamid, Hossam; Miles, Jonathan; Carrington, Richard W. J.; Hart, Alister; Loh, Alex; Skinner, John A.

    2015-01-01

    Introduction. Metal-on-metal (MoM) hip resurfacings have been associated with a variety of complications resulting from adverse reaction to metal debris. Pseudotumors have rarely been reported to cause deep venous thrombosis (DVT). Study Design. A case report and a review of the literature. Case Presentation. A 75-year-old female who had left metal-on-metal hip resurfacing 6 years ago presented with left groin pain associated with unilateral lower limb edema and swelling. By duplex and MRI studies, our patient had an extensive soft tissue necrosis associated with a large pelvic mass causing extensive DVT of the lower limb secondary to mechanical compression of the left iliac vein. Results. Our case was initially treated for DVT followed by dual surgical approach. The pseudotumor was excised through a separate iliofemoral approach and revision of the hip implant was undertaken through a posterior approach in the same setting. An inferior vena cava (IVC) filter was inserted to minimise the perioperative risks of handling the iliac veins. Conclusion. A combined approach with vascular surgeons is required. Combined resection of the pseudotumor and revision of the metal bearing surfaces is essential, in order to achieve a good surgical outcome in this rare complication. PMID:26457216

  11. Importance of head diameter, clearance, and cup wall thickness in elastohydrodynamic lubrication analysis of metal-on-metal hip resurfacing prostheses.

    PubMed

    Liu, Feng; Jin, Zhongmin; Roberts, P; Grigoris, P

    2006-08-01

    The main design features of metal-on-metal (MOM) hip resurfacing prostheses in promoting elastohydrodynamic lubrication were investigated in the present study, including the femoral head diameter, the clearance, and the cup wall thickness. Simplified conceptual models were developed, based on equivalent uniform wall thicknesses for both the cup and the head as well as the support materials representing bone and cement, and subsequently used for elastohydrodynamic lubrication analysis. Both typical first- and second-generation MOM hip resurfacing prostheses with different clearances and cup wall thicknesses were considered with a fixed large bearing diameter of 50 mm, as well as a 28 mm diameter MOM total hip replacement bearing for the purpose of comparison. The importance of the head diameter and the clearance in promoting elastohydrodynamic lubrication was confirmed. Furthermore, it was also predicted that a relatively thin acetabular cup in the more recently introduced second-generation MOM hip resurfacing prostheses would be capable of improving elastohydrodynamic lubrication even further.

  12. Which imaging modality is most effective for identifying pseudotumours in metal-on-metal hip resurfacings requiring revision

    PubMed Central

    Matharu, G. S.; Mansour, R.; Dada, O.; Ostlere, S.; Pandit, H. G.; Murray, D. W.

    2016-01-01

    Aims The aims of this study were to compare the diagnostic test characteristics of ultrasound alone, metal artefact reduction sequence MRI (MARS-MRI) alone, and ultrasound combined with MARS-MRI for identifying intra-operative pseudotumours in metal-on-metal hip resurfacing (MoMHR) patients undergoing revision surgery. Methods This retrospective diagnostic accuracy study involved 39 patients (40 MoMHRs). The time between imaging modalities was a mean of 14.6 days (0 to 90), with imaging performed at a mean of 5.3 months (0.06 to 12) before revision. The prevalence of intra-operative pseudotumours was 82.5% (n = 33). Results Agreement with the intra-operative findings was 82.5% (n = 33) for ultrasound alone, 87.5% (n = 35) for MARS-MRI alone, and 92.5% (n = 37) for ultrasound and MARS-MRI combined. The diagnostic characteristics for ultrasound alone and MARS-MRI alone reached similar sensitivities (90.9% vs 93.9%) and positive predictive values (PPVs; 88.2% vs 91.2%), but higher specificities (57.1% vs 42.9%) and negative predictive values (NPVs; 66.7% vs 50.0%) were achieved with MARS-MRI. Ultrasound and MARS-MRI combined produced 100% sensitivity and 100% NPV, whilst maintaining both specificity (57.1%) and PPV (91.7%). For the identification of a pseudotumour, which was confirmed at revision surgery, agreement was substantial for ultrasound and MARS-MRI combined (κ = 0.69), moderate for MARS-MRI alone (κ = 0.54), and fair for ultrasound alone (κ = 0.36). Discussion These findings suggest that ultrasound and/or MARS-MRI have a role when assessing patients with a MoMHR, with the choice dependent on local financial constraints and the availability of ultrasound expertise. However in patients with a MoMHR who require revision, combined imaging was most effective. Take home message: Combined imaging with ultrasound and MARS-MRI always identified intra-operative pseudotumours if present. Furthermore, if neither imaging modality showed a pseudotumour, one was not

  13. Curved-stem Hip Resurfacing

    PubMed Central

    2008-01-01

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

  14. The effect of 'running-in' on the tribology and surface morphology of metal-on-metal Birmingham hip resurfacing device in simulator studies.

    PubMed

    Vassiliou, K; Elfick, A P D; Scholes, S C; Unsworth, A

    2006-02-01

    It is well documented that hard bearing combinations show a running-in phenomenon in vitro and there is also some evidence of this from retrieval studies. In order to investigate this phenomenon, five Birmingham hip resurfacing devices were tested in a hip wear simulator. One of these (joint 1) was also tested in a friction simulator before, during, and after the wear test and surface analysis was conducted throughout portions of the testing. The wear showed the classical running in with the wear rate falling from 1.84 mm3 per 10(6) cycles for the first 10(6) cycles of testing to 0.24 mm3 per 10(6) cycles over the final 2 x 10(6) cycles of testing. The friction tests suggested boundary lubrication initially, but at 1 x 10(6) cycles a mixed lubrication regime was evident. By 2 x 10(6) cycles the classical Stribeck curve had formed, indicating a considerable contribution from the fluid film at higher viscosities. This continued to be evident at both 3 x 10(6) and 5 x 10(6) cycles. The surface study complements these findings.

  15. Metal-on-metal hip joint tribology.

    PubMed

    Dowson, D; Jin, Z M

    2006-02-01

    The basic tribological features of metal-on-metal total hip replacements have been reviewed to facilitate an understanding of the engineering science underpinning the renaissance of these hard-on-hard joints. Metal-on-polymer hip replacements operate in the boundary lubrication regime, thus leading to the design guidance to reduce the femoral head diameter as much as is feasible to minimize frictional torque and volumetric wear. This explains why the gold-standard implant of this form from the past half-century had a diameter of only 22.225 mm (7/8 in). Metal-on-metal implants can operate in the mild mixed lubrication regime in which much of the applied load is supported by elastohydrodynamic films. Correct tribological design leads to remarkably low steady state wear rates. Promotion of the most effective elastohydrodynamic films calls for the largest possible head diameters and the smallest clearances that can reasonably be adopted, consistent with fine surface finishes, good sphericity and minimal structural elastic deformation of the cup on its foundations. This guidance, which is opposite in form to that developed for metal-on-polymer joints, is equally valid for solid (monolithic) metallic heads on metallic femoral stems and surface replacement femoral shells. Laboratory measurements of friction and wear in metal-on-metal joints have confirmed their potential to achieve a very mild form of mixed lubrication. The key lies in the generation of effective elastohydrodynamic lubricating films of adequate thickness compared with the composite roughness of the head and cup. The calculation of the film thickness is by no means easy, but the full procedure is outlined and the use of an empirical formula that displays good agreement with calculations based upon the full numerical solutions is explained. The representation of the lambda ratio, lambda, embracing both film thickness and composite roughness, is described.

  16. Similar incidence of periprosthetic fluid collections after ceramic-on-polyethylene total hip arthroplasties and metal-on-metal resurfacing arthroplasties: results of a screening metal artefact reduction sequence-MRI study.

    PubMed

    Bisseling, P; de Wit, B W K; Hol, A M; van Gorp, M J; van Kampen, A; van Susante, J L C

    2015-09-01

    Patients from a randomised trial on resurfacing hip arthroplasty (RHA) (n = 36, 19 males; median age 57 years, 24 to 65) comparing a conventional 28 mm metal-on-metal total hip arthroplasty (MoM THA) (n = 28, 17 males; median age 59 years, 37 to 65) and a matched control group of asymptomatic patients with a 32 mm ceramic-on-polyethylene (CoP) THA (n = 33, 18 males; median age 63 years, 38 to 71) were cross-sectionally screened with metal artefact reducing sequence-MRI (MARS-MRI) for pseudotumour formation at a median of 55 months (23 to 72) post-operatively. MRIs were scored by consensus according to three different classification systems for pseudotumour formation. Clinical scores were available for all patients and metal ion levels for MoM bearing patients. Periprosthetic lesions with a median volume of 16 mL (1.5 to 35.9) were diagnosed in six patients in the RHA group (17%), one in the MoM THA group (4%) and six in the CoP group (18%). The classification systems revealed no clear differences between the groups. Solid lesions (n = 3) were exclusively encountered in the RHA group. Two patients in the RHA group and one in the MoM THA group underwent a revision for pseudotumour formation. There was no statistically significant relationship between clinical scoring, metal ion levels and periprosthetic lesions in any of the groups. Periprosthetic fluid collections are seen on MARS-MRI after conventional CoP THA and RHA and may reflect a soft-tissue collection or effusion. Currently available MRI classification systems seem to score these collections as pseudotumours, causing an-overestimatation of the incidence of pseudotumours. PMID:26330582

  17. Breast milk metal ion levels in a young and active patient with a metal-on-metal hip prosthesis.

    PubMed

    Nelis, Raymond; de Waal Malefijt, Jan; Gosens, Taco

    2013-01-01

    Metal-on-metal resurfacing arthroplasty of the hip has been used increasingly over the last 10 years in younger active patients. The dissolution of the metal wear particles results in measurable increases in cobalt and chromium ions in the serum and urine of patients with a metal-on-metal bearing. We measured the cobalt, chromium, and molybdenum ion levels in urine; serum; and breast milk in a young and active patient with a metal-on-metal hip prosthesis after a pathologic fracture of the femoral neck. Metal-on-metal hip prosthesis leads to increasing levels of molybdenum in breast milk in the short-term follow-up. There are no increasing levels of chromium and cobalt ions in breast milk. Besides the already known elevated concentrations in serum of chromium and cobalt after implantation of a metal-on-metal hip prosthesis, we found no increasing levels of chromium and cobalt in urine. PMID:22868068

  18. Three metal-on-metal hip replacement devices from the same manufacturer--a short- to mid-term survival.

    PubMed

    Kostensalo, Inari; Junnila, Mika; Mokka, Jari; Virolainen, Petri; Vahlberg, Tero; Mäkelä, Keijo T

    2014-06-01

    The aim of this retrospective study was to evaluate short- to mid-term results of three different metal-on-metal hip devices from the same manufacturer. A total of 329 hip operations were performed in a single academic unit between 2004 and 2010 using either Birmingham hip resurfacing or Synergy--Birmingham and Synergy--R3 total hip arthroplasty. The overall survival rate at the end of the follow-up time for Birmingham hip resurfacing was 88%, for Synergy--Birmingham total hip arthroplasty 95%, and for Synergy--R3 total hip arthroplasty 81% (p = 0.036). Five revision operations were performed due to adverse reaction to metal debris. Head sizes > 50 mm had lower revision rates compared to smaller ones. Synergy--R3 had a poor survival already at short-term. The mid-term survival of Birmingham hip resurfacing arthroplasty was inferior compared to previous studies.

  19. Results of hip resurfacing

    PubMed Central

    Favetti, Fabio; Casella, Filippo; Papalia, Matteo; Panegrossi, Gabriele

    2011-01-01

    Background The renewed popularity of resurfacing hip arthroplasty in the last 10 years has generated a remarkable quantity of scientific contributions based on mid- and short-term follow-up. More than one paper has reported a consistent early revision rate as a consequence of biological or biomechanical failure. Two major complications are commonly described with resurfacing implants: avascular necrosis and femoral-neck fracture. A close relationship between these two events has been suggested, but not firmly demonstrated, whereas cementing technique seems to be better understood as potential cause of failure. Methods We performed an in vitro study in which four different resurfacing implants were evaluated with a simulated femoral head, two types of cement, (low and high viscosity) and two cementing techniques: direct (cement apposition directly on the femoral head) and indirect (cement poured into the femoral component). Results High-viscosity cement showed homogeneous distribution over the entire femoral head. Low-viscosity cement showed a massive polar concentration with insufficient, if not absent, distribution in the equatorial zone. Conclusion Polar cement concentration could be a risk factor for early implant failure due to two effects on the femoral head: biological (excessive local exothermic reaction could cause osteocyte necrosis) and biomechanical (which could lead to uneven load distribution on the femoral head). PMID:21234563

  20. Metal-on-metal resurfacing arthroplasty: no way under the sun!--in the affirmative.

    PubMed

    Hungerford, David S

    2005-06-01

    I have been charged in this debate format to refute the idea suggested in the title. To do this, I will address 2 questions: (1) What problem does it solve? and (2) What risk does it pose? The answers to these questions will support my conclusion that metal-on-metal resurfacing arthroplasty is the wrong operation to be making a reappearance at this time.

  1. CoCrMo Metal-on-Metal Hip Replacements

    PubMed Central

    Liao, Yifeng; Hoffman, Emily; Wimmer, Markus; Fischer, Alfons; Jacobs, Joshua; Marks, Laurence

    2012-01-01

    After the rapid growth in the use of CoCrMo metal-on-metal hip replacements since the second generation was introduced circa 1990, metal-on-metal hip replacements have experienced a sharp decline in the last two years due to biocompatibility issues related to wear and corrosion products. Despite some excellent clinical results, the release of wear and corrosion debris and the adverse response of local tissues have been of great concern. There are many unknowns regarding how CoCrMo metal bearings interact with the human body. This perspective article is intended to outline some recent progresses in understanding wear and corrosion of metal-on-metal hip replacement both in-vivo and in-vitro. The materials, mechanical deformation, corrosion, wear-assisted corrosion, and wear products will be discussed. Possible adverse health effects caused by wear products will be briefly addressed, as well as some of the many open questions such as the detailed chemistry of corrosion, tribochemical reactions and the formation of graphitic layers. Nowadays we design almost routinely for high performance materials and lubricants for automobiles; humans are at least as important. It is worth remembering that a hip implant is often the difference between walking and leading a relatively normal life, and a wheelchair. PMID:23196425

  2. Metal-on-Metal Hip Arthroplasty: A Review of Adverse Reactions and Patient Management.

    PubMed

    Drummond, James; Tran, Phong; Fary, Camdon

    2015-01-01

    Recent alarming joint registry data highlighting increased revision rates has prompted further research into the area of metal-on-metal hip replacements and resurfacings. This review article examines the latest literature on the topic of adverse reactions to metal debris and summarises the most up-to-date guidelines on patient management. Adverse reactions to metal debris can cause significant damage to soft tissue and bone if not diagnosed early. Furthermore, not every patient with an adverse reaction to metal debris will be symptomatic. As such, clinicians must remain vigilant when assessing and investigating these patients in order to detect failing implants and initiate appropriate management. PMID:26132653

  3. Metal-on-Metal Hip Arthroplasty: A Review of Adverse Reactions and Patient Management

    PubMed Central

    Drummond, James; Tran, Phong; Fary, Camdon

    2015-01-01

    Recent alarming joint registry data highlighting increased revision rates has prompted further research into the area of metal-on-metal hip replacements and resurfacings. This review article examines the latest literature on the topic of adverse reactions to metal debris and summarises the most up-to-date guidelines on patient management. Adverse reactions to metal debris can cause significant damage to soft tissue and bone if not diagnosed early. Furthermore, not every patient with an adverse reaction to metal debris will be symptomatic. As such, clinicians must remain vigilant when assessing and investigating these patients in order to detect failing implants and initiate appropriate management. PMID:26132653

  4. Graphitic Tribological Layers in Metal-on-Metal Hip Replacements

    NASA Astrophysics Data System (ADS)

    Liao, Y.; Pourzal, R.; Wimmer, M. A.; Jacobs, J. J.; Fischer, A.; Marks, L. D.

    2011-12-01

    Arthritis is a leading cause of disability, and when nonoperative methods have failed, a prosthetic implant is a cost-effective and clinically successful treatment. Metal-on-metal replacements are an attractive implant technology, a lower-wear alternative to metal-on-polyethylene devices. Relatively little is known about how sliding occurs in these implants, except that proteins play a critical role and that there is a tribological layer on the metal surface. We report evidence for graphitic material in the tribological layer in metal-on-metal hip replacements retrieved from patients. As graphite is a solid lubricant, its presence helps to explain why these components exhibit low wear and suggests methods of improving their performance; simultaneously, this raises the issue of the physiological effects of graphitic wear debris.

  5. Hip resurfacing: history, current status, and future.

    PubMed

    Amstutz, Harlan C; Le Duff, Michel J

    2015-01-01

    Hip resurfacing arthroplasty (HRA) presents several advantages over conventional total hip arthroplasty (THA), including conservation and preservation of bone, reduced risk of dislocation, easy replication of hip biomechanics and easy revision if needed. It is a particularly appealing procedure for young patients. HRA has been performed for over 40 years following the same technological advances as THA. The bearing material used by most designs is metal-on-metal (MoM), which has the best compromise between strength and wear properties. However, MoM HRA has a specific set of possible complications. Aseptic femoral failures were initially the most prevalent cause for revision but progress in patient selection and surgical technique seem to have resolved this problem. Wear-related failures (high metal ion levels and adverse local tissue reactions) are now the main concern, and are essentially associated with poor acetabular component design and orientation, to which MoM is more sensitive than other bearing materials. The concept of functional coverage is key to understanding how MoM bearings are affected by edge wear. Only a 3-D assessment of cup position (e.g., the contact patch to rim distance) provides the necessary information to determine the role of cup positioning in relationship with abnormal bearing wear.The concept of hip resurfacing is more valid today than ever as the age of the patients in need of hip arthroplasty keeps getting lower. The recent publication of several excellent long-term survivorship results suggests that selection of a well-designed resurfacing system and accuracy in the placement of the cup can achieve long-term durability. PMID:26109156

  6. Edge loading in metal-on-metal hips: low clearance is a new risk factor

    PubMed Central

    Zografos, Angelos; Sayles, Ritchie S; Hart, Alister; Cann, Philippa

    2012-01-01

    The revision rate of large head metal-on-metal and resurfacing hips are significantly higher than conventional total hip replacements. The revision of these components has been linked to high wear caused by edge loading; which occurs when the head–cup contact patch extends over the cup rim. There are two current explanations for this; first, there is loss of entrainment of synovial fluid resulting in breakdown of the lubricating film and second, edge loading results in a large local increase in contact pressure and consequent film thickness reduction at the cup rim, which causes an increase in wear. This paper develops a method to calculate the distance between the joint reaction force vector and the cup rim – the contact patch centre to rim (CPCR) distance. However, the critical distance for the risk of edge loading is the distance from the contact patch edge to rim (CPER) distance. An analysis of explanted hip components, divided into edge worn and non-edge-worn components showed that there was no statistical difference in CPCR values, but the CPER value was significantly lower for edge worn hips. Low clearance hips, which have a more conformal contact, have a larger diameter contact patch and thus are more at risk of edge loading for similarly positioned hips. PMID:22558836

  7. Management of metal-on-metal hip implant patients: Who, when and how to revise?

    PubMed Central

    Berber, Reshid; Skinner, John A; Hart, Alister J

    2016-01-01

    The debate on how best to manage patients with metal-on-metal (MOM) hip implants continues. With over 1 million patients affected worldwide, the impact is far reaching. The majority of the aggressive failures of MOM hip implants have been dealt with by revision hip surgery, leaving patients with a much more indolent pattern of failure of devices that have been in situ for more than 10 years. The longer-term outcome for such patients remains unknown, and much debate exists on how best to manage these patients. Regulatory guidance is available but remains open to interpretation due to the lack of current evidence and long-term studies. Metal ion thresholds for concern have been suggested at 7 ppb for hip resurfacing arthroplasty and below this level for large diameter total hip arthroplasties. Soft tissue changes including pseudotumours and muscle atrophy have been shown to progress, but this is not consistent. New advanced imaging techniques are helping to diagnose complications with metal hips and the reasons for failure, however these are not widely available. This has led to some centres to tackle difficult cases through multidisciplinary collaboration, for both surgical management decisions and also follow-up decisions. We summarise current evidence and consider who is at risk, when revision should be undertaken and how patients should be managed. PMID:27190754

  8. The femoral head/neck offset and hip resurfacing.

    PubMed

    Beaulé, P E; Harvey, N; Zaragoza, E; Le Duff, M J; Dorey, F J

    2007-01-01

    Because the femoral head/neck junction is preserved in hip resurfacing, patients may be at greater risk of impingement, leading to abnormal wear patterns and pain. We assessed femoral head/neck offset in 63 hips undergoing metal-on-metal hip resurfacing and in 56 hips presenting with non-arthritic pain secondary to femoroacetabular impingement. Most hips undergoing resurfacing (57%; 36) had an offset ratio hips the mean offset ratio was 0.137 (0.04 to 0.23), with the offset ratio correlating negatively to an increasing alpha angle. An offset ratio or= 50.5 degrees. Most hips undergoing resurfacing have an abnormal femoral head/neck offset, which is best assessed in the sagittal plane. PMID:17259408

  9. Hip resurfacing: a large, US single-surgeon series.

    PubMed

    Brooks, P J

    2016-01-01

    Hip resurfacing has been proposed as an alternative to traditional total hip arthroplasty in young, active patients. Much has been learned following the introduction of metal-on-metal resurfacing devices in the 1990s. The triad of a well-designed device, implanted accurately, in the correct patient has never been more critical than with these implants. Following Food and Drug Administration approval in 2006, we studied the safety and effectiveness of one hip resurfacing device (Birmingham Hip Resurfacing) at our hospital in a large, single-surgeon series. We report our early to mid-term results in 1333 cases followed for a mean of 4.3 years (2 to 5.7) using a prospective, observational registry. The mean patient age was 53.1 years (12 to 84); 70% were male and 91% had osteoarthritis. Complications were few, including no dislocations, no femoral component loosening, two femoral neck fractures (0.15%), one socket loosening (0.08%), three deep infections (0.23%), and three cases of metallosis (0.23%). There were no destructive pseudotumours. Overall survivorship at up to 5.7 years was 99.2%. Aseptic survivorship in males under the age of 50 was 100%. We believe this is the largest United States series of a single surgeon using a single resurfacing system. PMID:26733633

  10. Balancing innovation and medical device regulation: the case of modern metal-on-metal hip replacements

    PubMed Central

    Howard, Jason J

    2016-01-01

    Due to problems with wear particle generation and subsequent loosening using conventional metal-on-polyethylene total hip replacements, there has been a shift toward alternative bearing systems, including metal-on-metal (MoM), for younger, more active patients with degenerative joint disease. Based on positive results from early short-term clinical studies, MoM hip replacements were readily adopted by orthopedic surgeons with thousands being implanted worldwide over the past decade. Unacceptably high revision rates reported by two national joint registries called into question the rigorousness of the regulatory approval process for these implants, particularly with respect to premarket data requirements to prove safety, effectiveness, and the appropriateness of the regulatory pathway chosen. The purpose of this review was to investigate the balance between facilitating the introduction of new medical technologies and the need to ensure safety and effectiveness through comprehensive regulatory assessment. The case of MoM hip replacement devices was used to frame the investigation and subsequent discussions. The regulatory approval processes and post-market surveillance requirements associated with three common MoM hip replacements (two resurfacings: the Birmingham and articular surface replacement and the articular surface replacement XL total hip replacement) were investigated. With respect to modern MoM hip replacement devices, the balance between facilitating the introduction of these new medical technologies and the need to ensure safety and effectiveness through comprehensive regulatory assessment was not achieved. The lessons learned from these experiences have application beyond joint replacements to the introduction of new medical technologies in general, particularly for those who have a significant potential for harm. In this regard, a series of recommendations have been developed to contribute to the evolution of the medical device regulatory process

  11. Balancing innovation and medical device regulation: the case of modern metal-on-metal hip replacements.

    PubMed

    Howard, Jason J

    2016-01-01

    Due to problems with wear particle generation and subsequent loosening using conventional metal-on-polyethylene total hip replacements, there has been a shift toward alternative bearing systems, including metal-on-metal (MoM), for younger, more active patients with degenerative joint disease. Based on positive results from early short-term clinical studies, MoM hip replacements were readily adopted by orthopedic surgeons with thousands being implanted worldwide over the past decade. Unacceptably high revision rates reported by two national joint registries called into question the rigorousness of the regulatory approval process for these implants, particularly with respect to premarket data requirements to prove safety, effectiveness, and the appropriateness of the regulatory pathway chosen. The purpose of this review was to investigate the balance between facilitating the introduction of new medical technologies and the need to ensure safety and effectiveness through comprehensive regulatory assessment. The case of MoM hip replacement devices was used to frame the investigation and subsequent discussions. The regulatory approval processes and post-market surveillance requirements associated with three common MoM hip replacements (two resurfacings: the Birmingham and articular surface replacement and the articular surface replacement XL total hip replacement) were investigated. With respect to modern MoM hip replacement devices, the balance between facilitating the introduction of these new medical technologies and the need to ensure safety and effectiveness through comprehensive regulatory assessment was not achieved. The lessons learned from these experiences have application beyond joint replacements to the introduction of new medical technologies in general, particularly for those who have a significant potential for harm. In this regard, a series of recommendations have been developed to contribute to the evolution of the medical device regulatory process

  12. Long-term outcome of a metal-on-polyethylene cementless hip resurfacing.

    PubMed

    Tan, Timothy L; Ebramzadeh, Edward; Campbell, Patricia A; Al-Hamad, Mariam; Amstutz, Harlan C

    2014-04-01

    Due to the well-documented problems surrounding metal-on-metal bearings, the use of hip resurfacing has declined. Since the potential benefits of hip resurfacing remain desirable, it may be beneficial to investigate the long-term outcome of hip resurfacings using metal-on-polyethylene in the 1980's. We report the long-term survivorship and modes of failure of a cementless metal-on-polyethylene resurfacing (n = 178) with different porous ingrowth surfaces. While acetabular loosening was absent, a high incidence of femoral failures (femoral loosening = 18.1%, osteolytic neck fracture = 21%) occurred despite using the same ingrowth surface for both components. Ongoing developments using the lessons learned from these previous generation components and utilizing modern low wear materials, e.g., cross-linked polyethylene, may lead to improved implants for future hip resurfacings. PMID:24090660

  13. Mechanical failure of metal-polyethylene sandwich liner in metal-on-metal total hip replacement.

    PubMed

    Oshima, Yasushi; Fetto, Joseph F

    2015-01-01

    Metal-on-metal had been proposed as an optimal articulation in THRs, however, many monoblock prostheses have been recalled in the USA because of significant high rates of early failure. Metal-on-metal prostheses had been implanted in our institution, and this is a case history of a single patient, in whom metal-on-metal THRs with different femoral sizes of heads were implanted. A 57-year-old female patient underwent bilateral total hip replacements with metal-on-metal prostheses using metal-polyethylene "sandwich" liners 9 years ago on the right side and 7 years ago on the left side respectively. The only difference in both sides was the femoral head diameter of 28 mm in right and 34 mm in left. Seven years after the left surgery, the acetabular liner was dissociated, however, metallosis was not detected. Although the larger femoral head was thought to increase hip joint stability, it dictated a reduction in polyethylene thickness in this prosthesis design, and it was 4 mm in the left hip. Recently, metal-on-metal articulations are thought not to be optimal for hip joint bearing surface, however, this clinical failure was due to the polyethylene thickness and quality.

  14. [Bionic surface design in metal on metal bearings for total hip arthroplasty--optimization of tribological characteristics].

    PubMed

    Böhling, U; Scholz, J; Thomas, W; Grundei, H

    2005-04-01

    Bionic systems are aiming to integrate natural observing into mechanical solutions. This has been realized in the design of metal on metal bearing in total hip resurface arthroplasty. The articular side of the femoral cup is covered with a dimple like surface. Under laboratory condition this so called "surf-metal-cup" achieved a reduction of the mechanical wear to almost a third part in comparison to a metal-cup with plane surface. This advantage, caused by the reduced friction-coefficient due to improved hydrodynamic lubrication could also be proved under laboratory conditions. The clinical introduction is expected to offer a significant extension of durability in this prosthetic system and needs to be proved in a long-term study.

  15. The effect of the metal-on-metal hip controversy on Internet search activity.

    PubMed

    Phelan, Nigel; Kelly, John C; Moore, David P; Kenny, Patrick

    2014-10-01

    The recall of the articular surface replacement (ASR) hip prosthesis in 2010 represents one of the most controversial areas in orthopaedic surgery in recent years. The aim of this study was to compare the impact of the metal-on-metal hip controversy on Internet search activity in four different regions and determine whether the number of related news reports affected Internet search activity. The Google Trends, Keywords and News applications were used to record the number of news articles and Internet search activity for the terms "hip recall", "metal-on-metal hip" and "ASR hip" from October 2009 to October 2012 in the USA, the UK, Australia and Ireland. There was a large increase in search activity following the official recall in August 2010 in all countries. There was significantly greater search activity after the recall in Ireland compared with the UK for the search term "hip recall" (P = 0.004). For the term "metal-on-metal hip", the UK had significantly more search activity (P = 0.0009). There was a positive correlation between the number of news stories in UK and Ireland with Internet search activity but not in the USA or Australia. Differences between countries affected by the same recall highlight the complex effects of the media on public awareness. The data demonstrates a window of opportunity prior to the official recall for the development of an awareness campaign to provide patients with accurate information.

  16. Taper Failure After Large-Diameter Metal-on-Metal Total Hip Arthroplasty.

    PubMed

    Goldstein, Zachary H; Estrera, Kenneth; Levine, Brett R

    2016-09-01

    The use of metal-on-metal bearing surfaces for total hip arthroplasty increased dramatically in the past decade for a variety of reasons, including the advantage of using larger-diameter femoral heads to reduce instability. However, recent research suggesting negative outcomes and high failure rates associated with some of these implants has decreased their use. Further, the use of larger-diameter femoral heads on relatively small femoral neck tapers has caused concern about localized corrosion at this junction, particularly with varus femoral alignment and longer femoral neck and head lengths. Although the advent of modular components offers the surgeon greater intraoperative flexibility, this modularity may prove to be a weak link when coupled with large-diameter femoral heads. This report describes a patient with a history of bilateral metal-on-metal total hip arthroplasty complicated by failure of the right hip as a result of fretting and mechanically assisted crevice corrosion. Notching of the femoral neck and head dissociation occurred 10 years after the primary procedure. The authors describe the patient's presenting symptoms, the possible etiology of the catastrophic failure, and the method of treatment and provide a brief review of metal-on-metal implants that may shed some light on the complications in this case. [Orthopedics.2016; 39(5):e984-e987.]. PMID:27248338

  17. The relationship between the angle of version and rate of wear of retrieved metal-on-metal resurfacings: a prospective, CT-based study.

    PubMed

    Hart, A J; Ilo, K; Underwood, R; Cann, P; Henckel, J; Lewis, A; Cobb, J; Skinner, J

    2011-03-01

    We measured the orientation of the acetabular and femoral components in 45 patients (33 men, 12 women) with a mean age of 53.4 years (30 to 74) who had undergone revision of metal-on-metal hip resurfacings. Three-dimensional CT was used to measure the inclination and version of the acetabular component, femoral version and the horizontal femoral offset, and the linear wear of the removed acetabular components was measured using a roundness machine. We found that acetabular version and combined version of the acetabular and femoral components were weakly positively correlated with the rate of wear. The acetabular inclination angle was strongly positively correlated with the rate of wear. Femoral version was weakly negatively correlated with the rate of wear. Application of a threshold of > 5 μm/year for the rate of wear in order to separate the revisions into low or high wearing groups showed that more high wearing components were implanted outside Lewinnek's safe zone, but that this was mainly due to the inclination of the acetabular component, which was the only parameter that significantly differed between the groups. We were unable to show that excess version of the acetabular component alone or combined with femoral version was associated with an increase in the rate of wear based on our assessment of version using CT. PMID:21357951

  18. Analysis of mixed lubrication mechanism in metal-on-metal hip joint replacements.

    PubMed

    Jin, Z M

    2002-01-01

    A simple mixed lubrication model has been developed to predict the asperity contact and wear for the metal-on-metal bearing couple for total hip joint replacements. It has been shown that the femoral head radius has a large effect on the predicted asperity contact and wear depending on the lubrication regime. An increase in the femoral head radius can lead to an increase in wear under a predominantly boundary lubrication regime, but this trend can be reversed under a mixed lubrication regime towards fluid film lubrication. These observations are consistent with the recent experimental findings from hip simulator studies by Smith and co-workers.

  19. Increased Mortality in Metal-on-Metal versus Non-Metal-on-Metal Primary Total Hip Arthroplasty at 10 Years and Longer Follow-Up: A Systematic Review and Meta-Analysis

    PubMed Central

    Meessen, J. M. T. A.; Fiocco, M.; van der Heide, H. J. L.; Sedrakyan, A.; Nelissen, R. G. H. H.

    2016-01-01

    Importance There are concerns about increased mortality in patients with metal-on-metal bearings in total hip arthroplasty (THA). Objective To determine the mortality and the morbidity in patients with metal-on-metal articulations (MOM THA) compared to patients with non-metal-on-metal articulations (non-MOM THA) after primary total hip arthroplasty. Data Sources Search of PubMed, MEDLINE, EMBASE, Web of Science, Cochrane, CINAHL, AcademicSearchPremier, ScienceDirect, Wiley and clinical trial registers through March 2015, augmented by a hand search of references from the included articles. No language restrictions were applied. Study Selection Two reviewers screened and identified randomised controlled trials and observational studies of primary total hip arthroplasty comparing MOM THA with non-MOM THA. Data Extraction and Synthesis Two reviewers independently extracted study data and assessed risk of bias. Risk differences (RD) were calculated with random effect models. Meta-regression was used to explore modifying factors. Main Outcomes and Measures Difference in mortality and difference in morbidity expressed as revisions and medical complications between patients with MOM THA and non-MOM THA. Results Forty-seven studies were included, comprising 4,000 THA in randomised trials and over 500,000 THA in observational studies. For mortality, random effects analysis revealed a higher pooled RD of 0.7%, 95%, confidence interval (CI) [0.0%, 2.3%], I-square 42%; the heterogeneity was explained by differences in follow-up. When restricted to studies with long term follow-up (i.e. 10 years or more), the RD for mortality was 8.5%, 95%, CI [5.8%, 11.2%]; number needed to treat was 12. Further subgroup analyses and meta-regression random effects models revealed no evidence for other moderator variables (study level covariates, e.g. resurfacing vs. non-resurfacing MOM) than follow-up duration. The quality of the evidence presented in this meta-analysis was characterized as

  20. Changes in bone mineral density of the acetabulum and proximal femur after total hip resurfacing arthroplasty.

    PubMed

    Huang, Qiang; Shen, Bin; Yang, Jing; Zhou, Zong-ke; Kang, Peng-de; Pei, Fu-xing

    2013-12-01

    Our aim was to investigate the changes in bone mineral density (BMD) of acetabulum and proximal femur after total hip resurfacing arthroplasty. A comparative study was carried out on 51 hips in 48 patients. Group A consisted of 25 patients (26 hips) who had undergone total hip resurfacing and group B consisted of 23 patients (25 hips) who had had large-diameter metal-on-metal total hip arthroplasty (THA). BMDs around the acetabulum and proximal femur were measured using dual-energy x-ray absorptiometry (DEXA) at 2 weeks, 6 months, 1 year and annually thereafter during the 3 years after surgery. At final follow-up, the acetabular net mean BMD decreased by 11% in group A and 10% in group B with no differences between two groups (P = .35). For the femoral side, in Gruen zone 1, the mean BMD increased by 4% in group A, whereas it decreased by 11% in group B (P = .029). In Gruen zone 7, the mean BMD increased by 8% at the final follow-up in group A, whereas it decreased by 13% in group B (P = .02). In both groups the mean BMD increased by 3% in Gruen zones 3, 4, 5, and 6. Stress-related bone loss of the acetabulum was comparable for MOM THA and resurfacing devices, but proximal femoral bone density increased in the resurfacing group and decreased in the THA group.

  1. Transient elastohydrodynamic lubrication analysis of metal-on-metal hip implant under simulated walking conditions.

    PubMed

    Liu, F; Jin, Z M; Hirt, F; Rieker, C; Roberts, P; Grigoris, P

    2006-01-01

    The transient elastohydrodynamic lubrication (EHL) analysis was performed in this study for a typical metal-on-metal bearing employing a polyethylene backing underneath a metallic cup inlay under dynamic operating conditions of load and speed representative of normal walking. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup. The governing Reynolds and elasticity equations were solved simultaneously by using both finite difference and finite element methods. The predicted transient film thickness from the present study was compared with the estimation based on the quasi-static analysis. It was found that the polyethylene backing employed in the typical metal-on-metal hip bearing, combined with dynamic squeeze-film action, significantly improved the transient lubricant film thickness under cyclic walking and consequently a fluid film lubrication regime was possible for smooth bearing surfaces with an average roughness less than 0.005 microm.

  2. Lubrication and friction prediction in metal-on-metal hip implants

    NASA Astrophysics Data System (ADS)

    Wang, F. C.; Brockett, C.; Williams, S.; Udofia, I.; Fisher, J.; Jin, Z. M.

    2008-03-01

    A general methodology of mixed lubrication analysis and friction prediction for a conforming spherical bearing in hip implants was developed, with particular reference to a typical metal-on-metal hip replacement. Experimental measurement of frictional torque for a similar implant was carried out to validate the theoretical prediction. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup under cyclic operating conditions of representative load and motion. The mixed lubrication model presented in this study was first applied to identify the contact characteristics on the bearing surfaces, consisting of both fluid-film and boundary lubricated regions. The boundary lubricated contact was assumed to occur when the predicted fluid film thickness was less than a typical boundary protein layer absorbed on the bearing surfaces. Subsequently, the friction was predicted from the fluid-film lubricated region with viscous shearing due to both Couette and Poiseuille flows and the boundary protein layer contact region with a constant coefficient of friction. The predicted frictional torque of the typical metal-on-metal hip joint implant was compared with the experimental measurement conducted in a functional hip simulator and a reasonably good agreement was found. The mixed lubrication regime was found to be dominant for the conditions considered. Although the percentage of the boundary lubricated region was quite small, the corresponding contribution to friction was quite large and the resultant friction factor was quite high.

  3. Lubrication and friction prediction in metal-on-metal hip implants.

    PubMed

    Wang, F C; Brockett, C; Williams, S; Udofia, I; Fisher, J; Jin, Z M

    2008-03-01

    A general methodology of mixed lubrication analysis and friction prediction for a conforming spherical bearing in hip implants was developed, with particular reference to a typical metal-on-metal hip replacement. Experimental measurement of frictional torque for a similar implant was carried out to validate the theoretical prediction. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup under cyclic operating conditions of representative load and motion. The mixed lubrication model presented in this study was first applied to identify the contact characteristics on the bearing surfaces, consisting of both fluid-film and boundary lubricated regions. The boundary lubricated contact was assumed to occur when the predicted fluid film thickness was less than a typical boundary protein layer absorbed on the bearing surfaces. Subsequently, the friction was predicted from the fluid-film lubricated region with viscous shearing due to both Couette and Poiseuille flows and the boundary protein layer contact region with a constant coefficient of friction. The predicted frictional torque of the typical metal-on-metal hip joint implant was compared with the experimental measurement conducted in a functional hip simulator and a reasonably good agreement was found. The mixed lubrication regime was found to be dominant for the conditions considered. Although the percentage of the boundary lubricated region was quite small, the corresponding contribution to friction was quite large and the resultant friction factor was quite high.

  4. Elastohydrodynamic lubrication analysis of metal-on-metal hip prostheses under steady state entraining motion.

    PubMed

    Jagatia, M; Jin, Z M

    2001-01-01

    The elastohydrodynamic lubrication problem of metal-on-metal hip joint replacements was considered in this study. A simple ball-in-socket configuration was used to represent the hip prosthesis. The Reynolds equation in a spherical coordinate was adopted for the fluid-film lubrication analysis, to account for the ball-in-socket geometry. The corresponding elastic deformation was calculated by means of the finite element method in order to consider the complex ball-in-socket geometry as well as the backing materials underneath the acetabular cup. Both the Reynolds and the elasticity equations were solved simultaneously using the Newton-Raphson finite difference method. The general methodology developed was then applied to a recent experimental prototype metal-on-metal hip implant. It was shown that the backing materials underneath the acetabular cup had little influence on the predicted contact pressure and the elastic deformation at the bearing surfaces for this particular example. Both the film thickness and the hydrodynamic pressure distributions were obtained under various loads up to 2500 N. The predicted minimum lubricating film thickness from the present study was compared with a simple estimation using the Hamrock and Dowson formulae based upon an equivalent ball-on-plane model and excellent agreement was found. However, it was pointed out that for some forms of metal-on-metal hip prostheses with a thin acetabular cup, a polyethylene inlay underneath a metallic bearing insert or a taper connection between a bearing insert and a fixation shell, the general methodology developed in the present study should be used and this will be considered in future studies.

  5. Cancer incidence and cause-specific mortality in patients with metal-on-metal hip replacements in Finland

    PubMed Central

    2014-01-01

    Background and purpose Metal-on-metal hip implants have been widely used, especially in the USA, Australia, England and Wales, and Finland. We assessed risk of death and updated data on the risk of cancer related to metal-on-metal hip replacements. Patients and methods A cohort of 10,728 metal-on-metal hip replacement patients and a reference cohort of 18,235 conventional total hip replacement patients were extracted from the Finnish Arthroplasty Register for the years 2001–2010. Data on incident cancer cases and causes of death until 2011 were obtained from the Finnish Cancer Registry and Statistics Finland. The relative risk of cancer and death were expressed as standardized incidence ratio (SIR) and standardized mortality ratio (SMR). SIR/SIR ratios and SMR/SMR ratios, and Poisson regression were used to compare the cancer risk and the risk of death between cohorts. Results The overall risk of cancer in the metal-on-metal cohort was not higher than that in the non-metal-on-metal cohort (RR = 0.91, 95% CI: 0.82–1.02). The risk of soft-tissue sarcoma and basalioma in the metal-on-metal cohort was higher than in the non-metal-on-metal cohort (SIR/SIR ratio = 2.6, CI: 1.02–6.4 for soft-tissue sarcoma; SIR/SIR ratio = 1.3, CI: 1.1–1.5 for basalioma). The overall risk of death in the metal-on-metal cohort was less than that in the non-metal-on-metal cohort (RR = 0.78, CI: 0.69–0.88). Interpretation The overall risk of cancer or risk of death because of cancer is not increased after metal-on-metal hip replacement. The well-patient effect and selection bias contribute substantially to the findings concerning mortality. Arthrocobaltism does not increase mortality in patients with metal-on-metal hip implants in the short term. However, metal-on-metal hip implants should not be considered safe until data with longer follow-up time are available. PMID:24397743

  6. Analysis of elastohydrodynamic lubrication in McKee-Farrar metal-on-metal hip joint replacement.

    PubMed

    Yew, A; Udofia, I; Jagatia, M; Jin, Z M

    2004-01-01

    An elastohydrodynamic lubrication (EHL) analysis was carried out in this study for a typical McKee-Farrar metal-on-metal hip prosthesis under a simple steady state rotation. The finite element method was used initially to investigate the effect of the cement and bone on the predicted contact pressure distribution between the two articulating surfaces under dry conditions, and subsequently to determine the elastic deformation of both the femoral and the acetabular components required for the lubrication analysis. Both Reynolds equation and the elasticity equation were coupled and solved numerically using the finite difference method. Important features in reducing contact stresses and promoting fluid-film lubrication associated with the McKee-Farrar metal-on-metal hip implant were identified as the large femoral head and the thin acetabular cup. For the typical McKee-Farrar metal-on-metal hip prosthesis considered under typical walking conditions, an increase in the femoral head radius from 14 to 17.4 mm (for a fixed radial clearance of 79 microm) was shown to result in a 25 per cent decrease in the maximum dry contact pressure and a 60 per cent increase in the predicted minimum film thickness. Furthermore, the predicted maximum contact pressure considering both the cement and the bone was found to be decreased by about 80 per cent, while the minimum film thickness was predicted to be increased by 50 per cent. Despite a significant increase in the predicted minimum lubricating film thickness due to the large femoral head and the thin acetabular cup, a mixed lubrication regime was predicted for the McKee-Farrar metal-on-metal hip implant under estimated in vivo steady state walking conditions, depending on the surface roughness of the bearing surfaces. This clearly demonstrated the important influences of the material, design and manufacturing parameters on the tribological performance of these hard-on-hard hip prostheses. Furthermore, in the present contact

  7. Early results of metal on metal articulation total hip arthroplasty in young patients.

    PubMed

    Mohamad, J A; Kwan, M K; Merican, A M; Abbas, A A; Kamari, Z H; Hisa, M K; Ismail, Z; Idrus, R M

    2004-12-01

    We report our early experience of 20 cases of metal on metal articulation total hip arthroplasty in 19 young patients. Avascular necrosis of the femoral head (63%) was the commonest diagnosis for patients undergoing this procedure, followed by osteoarthritis (21%). In general, most of the patients were young and physically active with an average age of 43.1 years (range, 25 to 58 years). The average follow-up period was 18 months (range, 7 to 46 months). The mean total Harris Hip Score preoperatively and at final follow-up was 31 points and 89 points respectively. The mean total Pain Score improved from an average of 11.5 to 41.1 points at final follow-up. Sixteen (84%) of the patients had a good to excellent hip score. There was one dislocation, which stabilized after reduction and conservative management. One case of early infection underwent a two-staged revision.

  8. 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.

  9. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral...

  10. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral...

  11. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral...

  12. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral...

  13. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral...

  14. The Tribology of Explanted Hip Resurfacings Following Early Fracture of the Femur

    PubMed Central

    Lord, James K.; Langton, David J.; Nargol, Antoni V.F.; Meek, R.M. Dominic; Joyce, Thomas J.

    2015-01-01

    A recognized issue related to metal-on-metal hip resurfacings is early fracture of the femur. Most theories regarding the cause of fracture relate to clinical factors but an engineering analysis of failed hip resurfacings has not previously been reported. The objective of this work was to determine the wear volumes and surface roughness values of a cohort of retrieved hip resurfacings which were removed due to early femoral fracture, infection and avascular necrosis (AVN). Nine resurfacing femoral heads were obtained following early fracture of the femur, a further five were retrieved due to infection and AVN. All fourteen were measured for volumetric wear using a co-ordinate measuring machine. Wear rates were then calculated and regions of the articulating surface were divided into “worn” and “unworn”. Roughness values in these regions were measured using a non-contacting profilometer. The mean time to fracture was 3.7 months compared with 44.4 months for retrieval due to infection and AVN. Average wear rates in the early fracture heads were 64 times greater than those in the infection and AVN retrievals. Given the high wear rates of the early fracture components, such wear may be linked to an increased risk of femoral neck fracture. PMID:26501331

  15. Effect of swing phase load on metal-on-metal hip lubrication, friction and wear.

    PubMed

    Williams, Sophie; Jalali-Vahid, Davood; Brockett, Claire; Jin, Zhongmin; Stone, Martin H; Ingham, Eileen; Fisher, John

    2006-01-01

    There is renewed interest in metal-on-metal (MOM) total hip replacements (THRs), however, variable wear rates have been observed clinically. It is hypothesised that changes in soft tissue tensioning during surgery may alter loading of THRs during the swing phase of gait leading to changes in fluid film lubrication, friction and wear. This study aimed to assess the effect of swing phase load on the lubrication, friction and wear of MOM hip replacements. Theoretical lubrication modelling was carried out using elastohydrodynamic theory. All the governing equations were solved numerically for the lubricant film thickness between the articulating surfaces under the transient dynamic conditions with low and high swing phase loads. Friction testing was completed using a single axis pendulum simulator, simplified loading cycles were applied with low and high swing phase loads. MOM hip replacements were tested in a hip simulator, modified to provide different swing phase loading regimes; a low (100 N) and a high load (as per ISO 14242-1; 280 N). Results demonstrated that the performance of MOM bearings is highly dependent on swing phase load. Hence, changes in the tension of the tissues at surgery and variations in muscle forces may increase swing phase load, reduce lubrication, increase friction and accelerate wear. This may explain some of the variations that have been observed with clinical wear rates.

  16. Tribolayer Formation in a Metal-on-Metal (MoM) Hip Joint: An Electrochemical Investigation

    PubMed Central

    Mathew, MT; Nagelli, C; Pourzal, R; Fischer, A; Laurent, MP; Jacobs, JJ; Wimmer, MA

    2013-01-01

    The demand for total hip replacement (THR) surgery is increasing in the younger population due to faster rehabilitation and more complete restoration of function. Up to 2009, metal-on-metal (MoM) hip joint bearings were a popular choice due to their design flexibility, post-operative stability and relatively low wear rates. The main wear mechanisms that occur along the bearing surface of MoM joints are tribochemical reactions that deposit a mixture of wear debris, metal ions and organic matrix of decomposed proteins known as a tribolayer. No in-depth electrochemical studies have been reported on the structure and characteristics of this tribolayer or about the parameters involved in its formation. In this study, we conducted an electrochemical investigation of different surfaces (bulk-like: control, nano-crystalline: new implant and tribolayer surface: retrieved implant) made out of two commonly used hip CoCrMo alloys (high-carbon and low-carbon). As per ASTM standard, cyclic polarization tests and electrochemical impedance spectroscopy tests were conducted. The results obtained from electrochemical parameters for different surfaces clearly indicated a reduction in corrosion for the tribolayer surface (Icorr: 0.76 μA/cm2). Further, polarization resistance (Rp:2.39±0.60MΩ/cm2) and capacitance (Cdl:15.20±0.75 μF/cm2) indicated variation in corrosion kinetics for the tribolayer surface, that attributed to its structure and stability in a simulated body environment. PMID:24099949

  17. The Inflammatory Phenotype in Failed Metal-On-Metal Hip Arthroplasty Correlates with Blood Metal Concentrations

    PubMed Central

    Paukkeri, Erja-Leena; Korhonen, Riku; Hämäläinen, Mari; Pesu, Marko; Eskelinen, Antti; Moilanen, Teemu; Moilanen, Eeva

    2016-01-01

    Introduction Hip arthroplasty is the standard treatment of a painful hip destruction. The use of modern metal-on-metal (MOM) bearing surfaces gained popularity in total hip arthroplasties during the last decade. Recently, worrisome failures due to adverse reaction to metal debris (ARMD), including pseudotumor response, have been widely reported. However, the pathogenesis of this reaction remains poorly understood. The aim of the present study was to investigate the ARMD response by flow cytometry approach. Methods Sixteen patients with a failed Articular Surface Replacement (ASR) hip prosthesis were included in the study. Samples of pseudotumor tissues collected during revision surgery were degraded by enzyme digestion and cells were typed by flow cytometry. Whole blood chromium and cobalt concentrations were analyzed with mass spectrometry before revision surgery. Results Flow cytometry analysis showed that the peri-implant pseudotumor tissue expressed two principal phenotypes, namely macrophage-dominated and T-lymphocyte-dominated response; the average portions being 54% (macrophages) and 25% (T-lymphocytes) in macrophage-dominated inflammation and 20% (macrophages) and 54% (T-lymphocytes) in T-lymphocyte-dominated response. The percentages of B-lymphocytes and granulocytes were lower in both phenotypes. Interestingly, the levels of blood chromium and cobalt were significantly higher in patients with macrophage-dominated response. Conclusions The results suggest that the adverse tissue reactions induced by MOM wear particles contain heterogeneous pathogeneses and that the metal levels are an important factor in the determination of the inflammatory phenotype. The present results support the hypothesis that higher metal levels cause cytotoxicity and tissue injury and macrophages are recruited to clear the necrotic debris. On the other hand, the adverse response developed in association with lower metal levels is T-lymphocyte-dominated and is likely to reflect

  18. Clinical and Wear Analyses of 9 Large Metal-on-Metal Total Hip Prostheses

    PubMed Central

    Mathijssen, N. M. C.; Witt, F.; Morlock, M. M.; Vehmeijer, S. B. W.

    2016-01-01

    Background Metal-on-Metal (MoM) total hip arthroplasties (THA) are associated with pseudotumor formation and high revision rates. This prospective study analysed the clinical and wear analyses of 9 large Metal-on-Metal (MoM) total hip arthroplasties (THA) to understand the underlying mechanisms of failure. The MoM bearings were revised for multiple reasons; the main reason was pseudotumor formation. Materials and Methods From 2006 till 2010 the Reinier de Graaf Hospital implanted 160 large head M2a-Magnum™ (Biomet Inc. Warsaw, Indiana, USA) THAs in 150 patients. The first year, 9 bearings were revised and analysed at the Biomechanics Section, Hamburg University of Technology, Germany. We performed clinical (Harris Hip Score, radiographic analysis, blood cobalt and chromium) and wear analysis (implant, tissue and fluid) of the 9 bearings. Since this study did not fall under the scope of the Medical Research Involving Human Subjects Act in The Netherlands, no ethical approval was necessary. In this prospective study all patient details were anonymized by the corresponding author, all other authors were blinded during the research and wear analyses. Patients with bilateral MoM implants were excluded. Results The 9 bearings had a median (IQR) survival of 41.0 (25) months in situ. From these bearings, three showed no noticeable wear. The median (IQR) head wear volume was 3.2 (3.6) mm3 and maximum wear depth 0.02 (0.02) mm. For the cup the median (IQR) wear volume was 0.23 (0.3) mm3 with a maximum wear depth of 0.03 (0.05) mm. Conclusion An early identification of parameters related to failure of the MoM THA, such as pain, decreased range of motion, radiographic changes and high levels of blood cobalt and chromium is of great importance for patient’s quality of life. Especially now patients and surgeons face the long term effects of all these bearings still in situ. This study reports the clinical and wear analyses of 9 MoM THA. In the majority of this group the

  19. 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. PMID:23538122

  20. Metal on metal total hip arthroplasty and a large groin mass: Not always adverse reaction to metallic debris

    PubMed Central

    Krishnan, Harry; Magnussen, Alex; Sharma, Aadhar; Skinner, John

    2014-01-01

    Due to their improved wear rates, Metal-on-metal bearings have been increasingly used in the past decade by orthopaedic surgeons carrying out total hip arthroplasty. However there is increasing evidence that there are significant complications associated with such implants. One well documented complication is that of metallic debris leading to pseudotumour formation, however there is less known about associations with other tumours within the pelvis. We present two cases where an intra-pelvic mass in patients with metal-on-metal implants were diagnosed as being of a different aetiology. This highlights the need for careful assessment of such patients in order to guide appropriate management. PMID:25560054

  1. Perfusion MRI in hips with metal-on-metal and metal-on-polyethylene total hip arthroplasty

    PubMed Central

    Anwander, H.; Cron, G. O.; Rakhra, K.

    2016-01-01

    Objectives Hips with metal-on-metal total hip arthroplasty (MoM THA) have a high rate of adverse local tissue reactions (ALTR), often associated with hypersensitivity reactions. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measures tissue perfusion with the parameter Ktrans (volume transfer constant of contrast agent). Our purpose was 1) to evaluate the feasibility of DCE-MRI in patients with THA and 2) to compare DCE-MRI in patients with MoM bearings with metal-on-polyethylene (MoP) bearings, hypothesising that the perfusion index Ktrans in hips with MoM THA is higher than in hips with MoP THA. Methods In this pilot study, 16 patients with primary THA were recruited (eight MoM, eight MoP). DCE-MRI of the hip was performed at 1.5 Tesla (T). For each patient, Ktrans was computed voxel-by-voxel in all tissue lateral to the bladder. The mean Ktrans for all voxels was then calculated. These values were compared with respect to implant type and gender, and further correlated with clinical parameters. Results There was no significant difference between the two bearing types with both genders combined. However, dividing patients by THA bearing and gender, women with MoM bearings had the highest Ktrans values, exceeding those of women with MoP bearings (0.067 min−1 versus 0.053 min−1; p-value < 0.05) and men with MoM bearings (0.067 min−1 versus 0.034 min−1; p-value < 0.001). Considering only the men, patients with MoM bearings had lower Ktrans than those with MoP bearings (0.034 min−1 versus 0.046 min−1; p < 0.05). Conclusion DCE-MRI is feasible to perform in tissues surrounding THA. Females with MoM THA show high Ktrans values in DCE-MRI, suggesting altered tissue perfusion kinematics which may reflect relatively greater inflammation. Cite this article: Dr P. E. Beaule. Perfusion MRI in hips with metal-on-metal and metal-on-polyethylene total hip arthroplasty: A pilot stud. Bone Joint Res 2016;5:73–79. DOI: 10

  2. Microfocus study of metal distribution and speciation in tissue extracted from revised metal on metal hip implants

    NASA Astrophysics Data System (ADS)

    Hart, Alister J.; Sandison, Ann; Quinn, Paul; Sampson, Barry; Atkinson, Kirk D.; Skinner, John A.; Goode, Angela; Powell, Jonathan J.; Mosselmans, J. Frederick W.

    2009-11-01

    Unexplained tissue inflammation in metal-on-metal hip replacements is suspected to be caused by implant-derived nanoparticles. The aim of this study was to investigate the nature of the metal particles in tissue surrounding metal-on-metal (MOM) hips that has been extracted during revision. Mapping of tissue surrounding the failed MOM hips was performed using microfocus X-ray Fluorescence (XRF). This revealed mainly Cr which was localized to the cellular regions. There was co-localisation of Co, were present, to areas of high Cr abundance. XANES of the tissue and appropriate standards revealed that the most common species were Cr(III) and Co(II). EXAFS analysis of the tissue and various metal standards revealed that the most abundant implant-related species was Cr(III) phosphate. Different tissue preparation methods, including frozen sectioning, were examined but were found not to affect the distribution or speciation of the metals in the tissue.

  3. A lexicon for wear of metal-on-metal hip prostheses.

    PubMed

    McKellop, Harry A; Hart, Alister; Park, Sang-Hyun; Hothi, Harry; Campbell, Pat; Skinner, John A

    2014-09-01

    Research on metal-on-metal (MoM) hip bearings has generated an extensive vocabulary to describe the wear processes and resultant surface damage. However, a lack of consistency and some redundancy exist in the current terminology. To facilitate the understanding of MoM tribology and to enhance communication of results among researchers and clinicians, we propose four categories of wear terminology: wear modes refer to the in vivo conditions under which the wear occurred; wear mechanisms refer to fundamental wear processes (adhesion, abrasion, fatigue, and tribochemical reactions); wear damage refers to the resultant changes in the morphology and/or composition of the surfaces; and wear features refer to the specific wear phenomena that are described in terms of the relevant modes, mechanisms, and damage. Clarifying examples are presented, but it is expected that terms will be added to the lexicon as new mechanisms and types of damage are identified. Corrosion refers to electrochemical processes that can remove or add material and thus also generate damage. Corrosion can act alone or may interact with mechanical wear. Examples of corrosion damage are also presented. However, an in-depth discussion of the many types of corrosion and their effects is beyond the scope of the present wear lexicon.

  4. Gender is a significant factor for failure of metal-on-metal total hip arthroplasty.

    PubMed

    Latteier, Michael J; Berend, Keith R; Lombardi, Adolph V; Ajluni, Andrew F; Seng, Brian E; Adams, Joanne B

    2011-09-01

    Metal-on-metal (MoM) articulations offers low wear, larger head size, and increased stability. Reports of early failure are troubling and include failure of ingrowth and metal articulation problems such as metallosis, hypersensitivity, pseudotumor, and unexplained pain. This study investigates the survivorship of modern MoM articulations by gender. We reviewed 1589 primary MoM THA in 1363 patients, with minimum 2-year follow-up for 1212 hips. Follow-up averaged 60 months. There were 643 female patients and 719 male patients. The incidence of cup revision was significantly higher in women than in men (8.2% vs 2.7%; P = .0000), as was incidence of aseptic loosening (4.3% vs 1.1%; P = .0006), and failure for metal-bearing complications (2.2% vs 0.6%; P = .0126). There appear to be gender factors influencing the success of MoM THA, which may include hormonal, anatomic, or functional differences. PMID:21641761

  5. Cross-sectional imaging of metal-on-metal hip arthroplasties

    PubMed Central

    Robinson, Elizabeth; Henckel, Johann; Sabah, Shiraz; Satchithananda, Keshthra; Skinner, John; Hart, Alister

    2014-01-01

    Background and purpose — Metal artifact reduction sequence (MARS) MRI is widely advocated for surveillance of metal-on-metal hip arthroplasties (MOM-HAs). However, its use is limited by susceptibility artifact at the prosthesis-bone interface, local availability, patient compliance, and cost (Hayter et al. 2011a). We wanted to determine whether CT is a suitable substitute for MARS MRI in evaluation of the painful MOM-HA. Patients and methods — 50 MOM-HA patients (30 female) with unexplained painful prostheses underwent MARS MRI and CT imaging. 2 observers who were blind regarding the clinical data objectively reported the following outcomes: soft tissue lesions (pseudotumors), muscle atrophy, and acetabular and femoral osteolysis. Diagnostic test characteristics were calculated. Results — Pseudotumor was diagnosed in 25 of 50 hips by MARS MRI and in 11 of 50 by CT. Pseudotumors were classified as type 1 (n = 2), type 2A (n = 17), type 2B (n = 4), and type 3 (n = 2) by MARS MRI. CT did not permit pseudotumor classification. The sensitivity of CT for diagnosis of pseudotumor was 44% (95% CI: 25–65). CT had “slight” agreement with MARS MRI for quantification of muscle atrophy (κ = 0.23, CI: 0.16–0.29; p < 0.01). Osteolysis was identified in 15 of 50 patients by CT. 4 of these lesions were identified by MARS MRI. Interpretation — CT was found to be superior to MRI for detection of osteolysis adjacent to MOM-HA, and should be incorporated into diagnostic algorithms. CT was unable to classify and failed to detect many pseudotumors, and it was unreliable for assessment of muscle atrophy. Where MARS MRI is contraindicated or unavailable, CT would be an unsuitable substitute and other modalities such as ultrasound should be considered PMID:25267500

  6. Midterm results of 36 mm metal-on-metal total hip arthroplasty

    PubMed Central

    Akrawi, Hawar; Hossain, Fahad S; Niculescu, Stefan; Hashim, Zaid; Ng, Arron Biing; Shetty, Ajit

    2016-01-01

    Background: Despite the many perceived benefits of metal-on-metal (MoM) articulation in total hip arthroplasty (THA), there have been growing concerns about metallosis and adverse reaction to metal debris (ARMD). Analysis of size 36 mm MoM articulation THAs is presented. These patients were evaluated for patient characteristics, relationship between blood metal ions levels and the inclination as well as the version of acetabular component, cumulative survival probability at final followup and functional outcome at final followup. Materials and Methods: 288, size 36 mm MoM THAs implanted in 269 patients at our institution from 2004 to 2010 were included in this retrospective study. These patients were assessed clinically for hip symptoms, perioperative complications and causes of revision arthroplasty were analysed. Biochemically, blood cobalt and chromium metal ions level were recorded and measurements of acetabular inclination and version were examined. Radiological evaluation utilizing Metal Artefact Reduction Sequence (MARS) MRI was undertaken and implant cumulative survivorship was evaluated. Results: The mean followup was 5 years (range 2–7 years), mean age was 73 years and the mean Oxford hip score was 36.9 (range 5–48). Revision arthroplasty was executed in 20 (7.4%) patients, of which 15 patients underwent single-stage revision THA. The causes of revision arthroplasty were: ARMD changes in 6 (2.2%) patients, infection in 5 (1.9%) patients and aseptic loosening in 5 (1.9%) patients. Three (1.1%) patients had their hips revised for instability, 1 (0.3%) for raised blood metal ions levels. The implant cumulative survival rate, with revision for any reason, was 68.9% at 7 years. Conclusions: Although medium-sized MoM THA with a 36 mm head has a marginally better survivorship at midterm followup, compared to larger size head MoM articulating THA, our findings nonetheless are still worryingly poor in comparison to what has been quoted in the literature

  7. Effect of wear of bearing surfaces on elastohydrodynamic lubrication of metal-on-metal hip implants.

    PubMed

    Liu, F; Jin, Z M; Hirt, F; Rieker, C; Roberts, P; Grigoris, P

    2005-09-01

    The effect of geometry change of the bearing surfaces owing to wear on the elastohydrodynamic lubrication (EHL) of metal-on-metal (MOM) hip bearings has been investigated theoretically in the present study. A particular MOM Metasul bearing (Zimmer GmbH) was considered, and was tested in a hip simulator using diluted bovine serum. The geometry of the worn bearing surface was measured using a coordinate measuring machine (CMM) and was modelled theoretically on the assumption of spherical geometries determined from the maximum linear wear depth and the angle of the worn region. Both the CMM measurement and the theoretical calculation were directly incorporated into the elastohydrodynamic lubrication analysis. It was found that the geometry of the original machined bearing surfaces, particularly of the femoral head with its out-of-roundness, could lead to a large reduction in the predicted lubricant film thickness and an increase in pressure. However, these non-spherical deviations can be expected to be smoothed out quickly during the initial running-in period. For a given worn bearing surface, the predicted lubricant film thickness and pressure distribution, based on CMM measurement, were found to be in good overall agreement with those obtained with the theoretical model based on the maximum linear wear depth and the angle of the worn region. The gradual increase in linear wear during the running-in period resulted in an improvement in the conformity and consequently an increase in the predicted lubricant film thickness and a decrease in the pressure. For the Metasul bearing tested in an AMTI hip simulator, a maximum total linear wear depth of approximately 13 microm was measured after 1 million cycles and remained unchanged up to 5 million cycles. This resulted in a threefold increase in the predicted average lubricant film thickness. Consequently, it was possible for the Metasul bearing to achieve a fluid film lubrication regime during this period, and this was

  8. How Do Metal Ion Levels Change over Time in Hip Resurfacing Patients? A Cohort Study

    PubMed Central

    Savarino, Lucia; Cadossi, Matteo; Chiarello, Eugenio; Fotia, Caterina; Greco, Michelina; Baldini, Nicola; Giannini, Sandro

    2014-01-01

    Metal-on-metal hip resurfacing (MOM-HR) is offered as an alternative to traditional hip arthroplasty for young, active adults with advanced osteoarthritis. Nevertheless, concerns remain regarding wear and corrosion of the bearing surfaces and the resulting increase in metal ion levels. We evaluated three cohorts of patients with Birmingham hip resurfacing (BHR) at an average follow-up of 2, 5, and 9 years. We asked whether there would be differences in ion levels between the cohorts and inside the gender. Nineteen patients were prospectively analyzed. The correlation with clinical-radiographic data was also performed. Chromium, cobalt, nickel, and molybdenum concentrations were measured by atomic absorption spectrophotometry. Chromium and cobalt levels demonstrated a tendency to decrease over time. Such tendency was present only in females. An inverse correlation between chromium, implant size, and Harris hip score was present at short term; it disappeared over time together with the decreased ion levels. The prospective analysis showed that, although metal ion levels remained fairly constant within each patient, there was a relatively large variation between subjects, so mean data in this scenario must be interpreted with caution. The chronic high exposure should be carefully considered during implant selection, particularly in young subjects, and a stricter monitoring is mandatory. PMID:25580456

  9. Bearing surfaces for hip arthroplasty - is metal-on-metal a passing fancy?

    PubMed

    Lee, Reginald K; Nevelos, Jim; Vigdorchik, Jonathan; Markel, David C

    2012-12-01

    Metal-on-metal bearings have had popularity that has waxed and waned over the years. The advantages realized relative to wear resistance and strength had been offset by early failures, manufacturing difficulty, and most recently by adverse soft tissue responses to the metallic debris. The bearing's history, evolution, advantages and disadvantages will be discussed in attempt to answer the question: is metal-on-metal a passing fancy?

  10. A case series of 35 hip revisions for adverse reactions to metal debris following Cormet hip resurfacing.

    PubMed

    Norris, Rory J; McArthur, John; Parsons, Helen; Smith, Nicholas A; Sprowson, Andrew P; Foguet, Pedro

    2014-12-01

    The primary aim of this study was to analyse our painful metal-on-metal (MoM) hip resurfacing revisions with evidence of 'adverse reactions to metal debris' (ARMD). In our series of 35 revisions the median whole blood Cobalt levels were 58 nmols/l (range 12-1407 nmols/l), and whole blood Chromium levels were 73 nmols/l (range 2-353 nmols/l). Thirty-four of our 35 patients had abnormal imaging on Ultrasound scanning (USS). The mean histological Campbell grading of ARMD was 4, and ranged from 0-9. The mean Oxford Hip Score (OHS) increased from 19 pre-revision (range 4-46) to 33 post-revision surgery (range 23-47).We found no correlation between the preoperative metal ion levels, and the severity of the disease or the outcome.Pain following hip resurfacing may arise from a number of causes and when groin pain arises in conjunction with abnormal cross sectional imaging we have offered our patients revision surgery regardless of raised metal ions or grossly abnormal imaging, with good results.

  11. The Influence of Surgical Approach on Outcome in Birmingham Hip Resurfacing

    PubMed Central

    Revell, Matthew P.; Thomas, Andrew M.; Treacy, Ronan B.; Pynsent, Paul B.

    2008-01-01

    Various approaches have been described for metal-on-metal hip resurfacing. We compared the posterolateral and direct lateral approaches for complications, pain, function, and implant survival in the short and medium term for two surgeons in a consecutive series of 790 patients (909 hips; July 1997 to July 2004) followed until July 2007. The direct lateral approach group included 135 resurfacing procedures and the posterolateral group included 774 procedures. There was no difference between the two groups for age or gender. The minimum followup for the anterolateral group was 2 years (mean, 5.1 years; range, 2.0–9.4 years) and for the posterolateral group 2 years (mean, 5.5 years; range, 2.0–9.6 years). There were no differences between the two approaches for complications, additional surgery, implant survival, or Oxford hip scores. The 8-year survival rate was 97.9% (95% confidence interval, 89.9–100) for the direct lateral approach and 97.2% (95% confidence interval, 93.9–99.3) for the posterolateral approach. This study indicates both approaches offer excellent pain reduction and return to function after Birmingham hip resurfacing with no difference in survival or in the incidence of complications. An 8-year survival rate of 97% can be achieved using either the posterolateral approach or the direct lateral approach. Level of Evidence: Level III, therapeutic study. See the Guidelines for authors for a complete description of levels of evidence. PMID:18224379

  12. Increased risk of revision of cementless stemmed total hip arthroplasty with metal-on-metal bearings

    PubMed Central

    Pedersen, Alma B; Mäkelä, Keijo; Eskelinen, Antti; Havelin, Leif Ivar; Furnes, Ove; Kärrholm, Johan; Garellick, Göran; Overgaard, Søren

    2015-01-01

    Background and purpose Data from the national joint registries in Australia and England and Wales have revealed inferior medium-term survivorship for metal-on-metal (MoM) total hip arthroplasty (THA) than for metal-on-polyethylene (MoP) THA. Based on data from the Nordic Arthroplasty Register Association (NARA), we compared the revision risk of cementless stemmed THA with MoM and MoP bearings and we also compared MoM THA to each other. Patients and methods We identified 32,678 patients who were operated from 2002 through 2010 with cementless stemmed THA with either MoM bearings (11,567 patients, 35%) or MoP bearings (21,111 patients, 65%). The patients were followed until revision, death, emigration, or the end of the study period (December 31, 2011), and median follow-up was 3.6 (interquartile range (IQR): 2.4–4.8) years for MoM bearings and 3.4 (IQR: 2.0–5.8) years for MoP bearings. Multivariable regression in the presence of competing risk of death was used to assess the relative risk (RR) of revision for any reason (with 95% confidence interval (CI)). Results The cumulative incidence of revision at 8 years of follow-up was 7.0% (CI: 6.0–8.1) for MoM bearings and 5.1% (CI: 4.7–5.6) for MoP bearings. At 6 years of follow-up, the RR of revision for any reason was 1.5 (CI: 1.3–1.7) for MoM bearings compared to MoP bearings. The RR of revision for any reason was higher for the ASR (adjusted RR = 6.4, CI: 5.0–8.1), the Conserve Plus (adjusted RR = 1.7, CI: 1.1–2.5) and “other” acetabular components (adjusted RR = 2.4, CI: 1.5–3.9) than for MoP THA at 6 years of follow-up. Interpretation At medium-term follow-up, the survivorship for cementless stemmed MoM THA was inferior to that for MoP THA, and metal-related problems may cause higher revision rates for MoM bearings with longer follow-up. PMID:25715878

  13. Contact mechanics and elastohydrodynamic lubrication in a novel metal-on-metal hip implant with an aspherical bearing surface.

    PubMed

    Meng, Qingen; Gao, Leiming; Liu, Feng; Yang, Peiran; Fisher, John; Jin, Zhongmin

    2010-03-22

    Diameter and diametral clearance of the bearing surfaces of metal-on-metal hip implants and structural supports have been recognised as key factors to reduce the dry contact and hydrodynamic pressures and improve lubrication performance. On the other hand, application of aspherical bearing surfaces can also significantly affect the contact mechanics and lubrication performance by changing the radius of the curvature of a bearing surface and consequently improving the conformity between the head and the cup. In this study, a novel metal-on-metal hip implant employing a specific aspherical bearing surface, Alpharabola, as the acetabular surface was investigated for both contact mechanics and elastohydrodynamic lubrication under steady-state conditions. When compared with conventional spherical bearing surfaces, a more uniform pressure distribution and a thicker lubricant film thickness within the loaded conjunction were predicted for this novel Alpharabola hip implant. The effects of the geometric parameters of this novel acetabular surface on the pressure distribution and lubricant thickness were investigated. A significant increase in the predicted lubricant film thickness and a significant decrease in the dry contact and hydrodynamic pressures were found with appropriate combinations of these geometric parameters, compared with the spherical bearing surface.

  14. Meeting the demands of on-going metal-on-metal hip surveillance through nurse led services.

    PubMed

    Elliott, Sue; Langfield, Sarah

    2016-02-01

    This paper discusses the implications following a recall of all metal-on-metal hip replacements by the Medicines and Healthcare products regulatory Agency (MHRA). Issues identified were the release of metal ions from the metal implants. These ions were found to seep into local tissues and cause reactions that destroyed muscle and bone leaving some patients with long term disability. At the centre surveillance was monitored by an extension of the current Nurse Led services using existing staff and resources. There were a significant number of patients that required monitoring and there were difficulties contacting these patients and ensuring that they understood the importance of attending a clinic. PMID:26772766

  15. Effect of bearing geometry and structure support on transient elastohydrodynamic lubrication of metal-on-metal hip implants.

    PubMed

    Liu, Feng; Jin, Zhongming; Roberts, Paul; Grigoris, Peter

    2007-01-01

    An effective lubrication can significantly reduce wear of metal-on-metal artificial hip joints. The improvement of the lubrication can be achieved through the optimisation of the bearing geometry in terms of a small clearance and/or the structural support such as a polyethylene backing underneath a metallic bearing in a sandwich acetabular cup form. The separate effects of these two factors on fluid film lubrication of 28 mm diameter metal-on-metal total hip joints under walking conditions were numerically investigated in this paper. The results show that a larger lubricant film due to the polyethylene backing can be significantly enhanced by the transient squeeze-film action, particularly during the stance phase, and a similar lubricant film can be developed for both the monolithic cup relying on the smaller clearance and the sandwich cup benefiting from the polyethylene backing. Both cup systems can function in a wide range of lubrication regimes, covering both mixed and fluid film, under the current design and manufacture conditions.

  16. Progressive Cardiomyopathy in a Patient With Elevated Cobalt Ion Levels and Bilateral Metal-on-Metal Hip Arthroplasties.

    PubMed

    Mosier, Brian A; Maynard, Lance; Sotereanos, Nicholas G; Sewecke, Jeffrey J

    2016-01-01

    Systemic cobalt toxicity is a rare complication after metal-on-metal (MOM) total hip arthroplasty. Here we present a case of progressive cardiomyopathy, as evidenced by biopsy and cardiac magnetic resonance imaging (MRI), in a patient with bilateral MOM total hip arthroplasties. To our knowledge, it is one of the first cases in which cardiomyopathy resulting from systemic cobalt disease has been shown on MRI. While there is no guideline to unequivocally diagnose cobalt cardiomyopathy, the constellation of findings, including pathologic, biologic, blood levels, imaging, and surgical, all uniformly indicate a unifying diagnosis. The lack of improvement after removal of the prosthetic device supports a diagnosis of permanent myocardial damage, which is consistent with cardiomyopathy of advanced toxic etiology.

  17. Changes in metal levels and chromosome aberrations in the peripheral blood of patients after metal-on-metal hip arthroplasty.

    PubMed

    Ladon, Dariusz; Doherty, Ann; Newson, Roger; Turner, Justine; Bhamra, Manjit; Case, C Patrick

    2004-12-01

    A prospective study was performed to investigate changes in metal levels and chromosome aberrations in patients within 2 years of receiving metal-on-metal hip arthroplasties. There was a statistically significant increase of cobalt and chromium concentrations, with a small increase in molybdenum, in whole blood at 6, 12, and 24 months after surgery. There was also a statistically significant increase of both chromosome translocations and aneuploidy in peripheral blood lymphocytes at 6, 12, and 24 months after surgery. The changes were generally progressive with time, but the change in aneuploidy was much greater than in chromosome translocations. No statistically significant correlations were found in secondary analyses between chromosome translocation indices and cobalt or chromium concentration in whole blood. Although the clinical consequences of these changes, if any, are unknown, future epidemiological studies could usefully include direct comparisons of patients with implants of different composition.

  18. Cobalt to Chromium Ratio is Not a Key Marker for Adverse Local Tissue Reaction (ALTR) in Metal on Metal Hips.

    PubMed

    Fehring, Thomas K; Carter, Joshua L; Fehring, Keith A; Odum, Susan M; Griffin, William L

    2015-09-01

    The diagnosis of adverse local tissue reaction (ALTR) after metal-on-metal total hip arthroplasty (MoMTHA) presents a significant challenge. No single biomarker is specific for ALTR. The purpose of this study was to determine if the ratio of cobalt to chromium ions is useful for diagnosing ALTR in MoMTHA. In 89 bearing-related revision THAs, preoperative cobalt and chromium ion levels were compared to an intraoperative soft tissue damage grading scale. The average cobalt to chromium ratio was 2.96 (0-20). There was no correlation between the tissue scale and the cobalt to chromium ratio (R=0.095; P=0.41). Many variables affecting ion production/excretion mitigate the use of the ion ratio. The cobalt to chromium ratio is not a predictive biomarker for ALTR in MoMTHA.

  19. Prevalence of Failure due to Adverse Reaction to Metal Debris in Modern, Medium and Large Diameter Metal-on-Metal Hip Replacements--The Effect of Novel Screening Methods: Systematic Review and Metaregression Analysis.

    PubMed

    Reito, Aleksi; Lainiala, Olli; Elo, Petra; Eskelinen, Antti

    2016-01-01

    Metal-on-metal (MoM) hip replacements were used for almost a decade before adverse reactions to metal debris (ARMD) were found to be a true clinical problem. Currently, there is a paucity of evidence regarding the usefulness of systematic screening for ARMD. We implemented a systematic review and meta-analysis to establish the prevalence of revision confirmed ARMD stratified by the use of different screening protocols in patients with MoM hip replacements. Five levels of screening were identified: no screening (level 0), targeted blood metal ion measurement and/or cross-sectional imaging (level 1), metal ion measurement without imaging (level 2), metal ion measurement with targeted imaging (level 3) and comprehensive screening (both metal ions and imaging for all; level 4). 122 studies meeting our eligibility criteria were included in analysis. These studies included 144 study arms: 100 study arms with hip resurfacings, 33 study arms with large-diameter MoM total hip replacements (THR), and 11 study arms with medium-diameter MoM THRs. For hip resurfacing, the lowest prevalence of ARMD was seen with level 0 screening (pooled prevalence 0.13%) and the highest with level 4 screening (pooled prevalace 9.49%). Pooled prevalence of ARMD with level 0 screening was 0.29% and with level 4 screening 21.3% in the large-diameter MoM THR group. In metaregression analysis of hip resurfacings, level 4 screening was superior with regard to prevalence of ARMD when compared with other levels. In the large diameter THR group level 4 screening was superior to screening 0,2 and 3. These outcomes were irrespective of follow-up time or study publication year. With hip resurfacings, routine cross-sectional imaging regardless of clinical findings is advisable. It is clear, however, that targeted metal ion measurement and/or imaging is not sufficient in the screening for ARMD in any implant concepts. However, economic aspects should be weighed when choosing the preferred screening level

  20. Prevalence of Failure due to Adverse Reaction to Metal Debris in Modern, Medium and Large Diameter Metal-on-Metal Hip Replacements – The Effect of Novel Screening Methods: Systematic Review and Metaregression Analysis

    PubMed Central

    Reito, Aleksi; Lainiala, Olli; Elo, Petra; Eskelinen, Antti

    2016-01-01

    Metal-on-metal (MoM) hip replacements were used for almost a decade before adverse reactions to metal debris (ARMD) were found to be a true clinical problem. Currently, there is a paucity of evidence regarding the usefulness of systematic screening for ARMD. We implemented a systematic review and meta-analysis to establish the prevalence of revision confirmed ARMD stratified by the use of different screening protocols in patients with MoM hip replacements. Five levels of screening were identified: no screening (level 0), targeted blood metal ion measurement and/or cross-sectional imaging (level 1), metal ion measurement without imaging (level 2), metal ion measurement with targeted imaging (level 3) and comprehensive screening (both metal ions and imaging for all; level 4). 122 studies meeting our eligibility criteria were included in analysis. These studies included 144 study arms: 100 study arms with hip resurfacings, 33 study arms with large-diameter MoM total hip replacements (THR), and 11 study arms with medium-diameter MoM THRs. For hip resurfacing, the lowest prevalence of ARMD was seen with level 0 screening (pooled prevalence 0.13%) and the highest with level 4 screening (pooled prevalace 9.49%). Pooled prevalence of ARMD with level 0 screening was 0.29% and with level 4 screening 21.3% in the large-diameter MoM THR group. In metaregression analysis of hip resurfacings, level 4 screening was superior with regard to prevalence of ARMD when compared with other levels. In the large diameter THR group level 4 screening was superior to screening 0,2 and 3. These outcomes were irrespective of follow-up time or study publication year. With hip resurfacings, routine cross-sectional imaging regardless of clinical findings is advisable. It is clear, however, that targeted metal ion measurement and/or imaging is not sufficient in the screening for ARMD in any implant concepts. However, economic aspects should be weighed when choosing the preferred screening level

  1. Does bearing size influence metal ion levels in large-head metal-on-metal total hip arthroplasty? A comparison of three total hip systems

    PubMed Central

    2014-01-01

    Background The purpose of the study was twofold: first, to determine whether there is a statistically significant difference in the metal ion levels among three different large-head metal-on-metal (MOM) total hip systems. The second objective was to assess whether position of the implanted prostheses, patient demographics or factors such as activity levels influence overall blood metal ion levels and whether there is a difference in the functional outcomes between the systems. Methods In a cross-sectional cohort study, three different metal-on-metal total hip systems were assessed: two monoblock heads, the Durom socket (Zimmer, Warsaw, IN, USA) and the Birmingham socket (Smith and Nephew, Memphis, TN, USA), and one modular metal-on-metal total hip system (Pinnacle, Depuy Orthopedics, Warsaw, IN, USA). Fifty-four patients were recruited, with a mean age of 59.7 years and a mean follow-up time of 41 months (12 to 60). Patients were evaluated clinically, radiologically and biochemically. Statistical analysis was performed on all collected data to assess any differences between the three groups in terms of overall blood metal ion levels and also to identify whether there was any other factor within the group demographics and outcomes that could influence the mean levels of Co and Cr. Results Although the functional outcome scores were similar in all three groups, the blood metal ion levels in the larger monoblock large heads (Durom, Birmingham sockets) were significantly raised compared with those of the Pinnacle group. In addition, the metal ion levels were not found to have a statistically significant relationship to the anteversion or abduction angles as measured on the radiographs. Conclusions When considering a MOM THR, the use of a monoblock large-head system leads to higher elevations in whole blood metal ions and offers no advantage over a smaller head modular system. PMID:24472283

  2. The effect of femoral head diameter upon lubrication and wear of metal-on-metal total hip replacements.

    PubMed

    Smith, S L; Dowson, D; Goldsmith, A A

    2001-01-01

    It has been found that a remarkable reduction in the wear of metal-on-metal hip joints can be achieved by simply increasing the diameter of the joint. A tribological evaluation of metal-on-metal joints of 16, 22.225, 28 and 36 mm diameter was conducted in 25 per cent bovine serum using a hip joint simulator. The joints were subject to dynamic motion and loading cycles simulating walking for both lubrication and wear studies. For each size of joint in the lubrication study, an electrical resistivity technique was used to detect the extent of surface separation through a complete walking cycle. Wear of each size of joint was measured gravimetrically in wear tests of at least 2 x 10(6) cycles duration. Joints of 16 and 22.225 mm diameter showed no surface separation in the lubrication study. This suggested that wear would be proportional to the sliding distance and hence joint size in this boundary lubrication regime. A 28 mm diameter joint showed only limited evidence of surface separation suggesting that these joints were operating in a mixed lubrication regime. A 36 mm diameter joint showed surface separation for considerable parts of each walking cycle and hence evidence of the formation of a protective lubricating film. Wear testing of 16 and 22.225 mm diameter metal-on-metal joints gave mean wear rates of 4.85 and 6.30 mm3/10(6) cycles respectively. The ratio of these wear rates, 0.77, is approximately the same as the joint diameters ratio, 16/22.225 or 0.72, as expected from simple wear theory for dry or boundary lubrication conditions. No bedding-in was observed with these smaller diameter joints. For the 28 mm diameter joint, from 0 to 2 x 10(6) cycles, the mean wear rate was 1.62 mm3/10(6) cycles as the joints bedded-in. Following bedding-in, from 2.0 x 10(6) to 4.7 x 10(6) cycles, the wear rate was 0.54 mm3/10(6) cycles. As reported previously by Goldsmith et al. in 2000 [1], the mean steady state wear rate of the 36 mm diameter joints was lower than those

  3. ELIGIBILITY FOR THE HIP-RESURFACING ARTHROPLASTY PROCEDURE: AN EVALUATION ON 592 HIPS

    PubMed Central

    Queiroz, Roberto Dantas; Faria, Rafael Salomon Silva; Duarte, David Marcelo; Takano, Marcelo Itiro; Sugiyama, Mauricio Morita

    2015-01-01

    Objective: To investigate the percentage of ideal patients who would be eligible for hip-resurfacing surgery at a reference service for hip arthroplasty. Methods: Out of all the cases of hip arthroplasty operated at Hospital do Servidor Público Estadual de São Paulo (HSPE) between January 2009 and December 2010, we assessed a total of 592 procedures that would fit the criteria for indication for resurfacing arthroplasty, after clinical and radiological evaluation according to the criteria established by the Food and Drug Administration (FDA) and by Seyler et al. Results: Among the total number of hip replacement arthroplasty cases, 5.74% of the patients were eligible. Among the patients who underwent primary arthroplasty, we found that 8.23% presented ideal conditions for this procedure. Conclusion: The study demonstrated that this type of surgery still has a limited role among hip surgery methods. PMID:27047851

  4. Are all metal-on-metal hip revision operations contributing to the National Joint Registry implant survival curves?

    PubMed Central

    Sabah, S. A.; Henckel, J.; Koutsouris, S.; Rajani, R.; Hothi, H.; Skinner, J. A.; Hart, A. J.

    2016-01-01

    Aims The National Joint Registry for England, Wales and Northern Ireland (NJR) has extended its scope to report on hospital, surgeon and implant performance. Data linkage of the NJR to the London Implant Retrieval Centre (LIRC) has previously evaluated data quality for hip primary procedures, but did not assess revision records. Methods We analysed metal-on-metal hip revision procedures performed between 2003 and 2013. A total of 69 929 revision procedures from the NJR and 929 revised pairs of components from the LIRC were included. Results We were able to link 716 (77.1%) revision procedures on the NJR to the LIRC. This meant that 213 (22.9%) revision procedures at the LIRC could not be identified on the NJR. We found that 349 (37.6%) explants at the LIRC completed the full linkage process to both NJR primary and revision databases. Data completion was excellent (> 99.9%) for revision procedures reported to the NJR. Discussion This study has shown that only approximately one third of retrieved components at the LIRC, contributed to survival curves on the NJR. We recommend prospective registry-retrieval linkage as a tool to feedback missing and erroneous data to the NJR and improve data quality. Take home message: Prospective Registry – retrieval linkage is a simple tool to evaluate and improve data quality on the NJR. Cite this article: Bone Joint J 2016;98-B:33–9. PMID:26733513

  5. Clinical usefulness of blood metal measurements to assess the failure of metal-on-metal hip implants

    PubMed Central

    Sampson, Barry; Hart, Alister

    2012-01-01

    In April 2010, a Medicines and Healthcare Products Regulatory Agency safety alert concerning all metal-on-metal (MOM) hip replacements recommended measuring chromium and cobalt concentrations when managing patients with painful prostheses. The need for this review is illustrated by the recent surge in requests for these blood tests from orthopaedic surgeons following this alert. The aim is to provide guidance to laboratories in assessing these requests and advising clinicians on interpretation. First, we summarize the basic terminology regarding the types of hip replacements, with emphasis on the MOM type. Second, we describe the clinical concerns over implant-derived wear debris in the local tissues and distant sites. Analytical aspects of the measurement of the relevant metal ions and what factors affect the levels measured are discussed. The application of inductively coupled plasma mass spectrometry techniques to the measurement of these metals is considered in detail. The biological effects of metal wear products are summarized with local toxicity and systemic biological effects considered, including carcinogenicity, genotoxicity and systemic toxicity. Clinical cases are used to illustrate pertinent points. PMID:22155921

  6. No association between serum metal ions and implant fixation in large-head metal-on-metal total hip arthroplasty

    PubMed Central

    Søballe, Kjeld; Jakobsen, Stig Storgaard; Lorenzen, Nina Dyrberg; Mechlenburg, Inger; Stilling, Maiken

    2014-01-01

    Background The mechanism of failure of metal-on-metal (MoM) total hip arthroplasty (THA) has been related to a high rate of metal wear debris, which is partly generated from the head-trunnion interface. However, it is not known whether implant fixation is affected by metal wear debris. Patients and methods 49 cases of MoM THA in 41 patients (10 women) with a mean age of 52 (28–68) years were followed with stereoradiographs after surgery and at 1, 2, and 5 years to analyze implant migration by radiostereometric analysis (RSA). Patients also participated in a 5- to 7-year follow-up with measurement of serum metal ions, questionnaires (Oxford hip score (OHS) and Harris hip score (HHS)), and measurement of cup and stem positions and systemic bone mineral density. Results At 1–2 years, mean total translation (TT) was 0.04 mm (95% CI: –0.07 to 0.14; p = 0.5) for the stems; at 2–5 years, mean TT was 0.13 mm (95% CI: –0.25 to –0.01; p = 0.03), but within the precision limit of the method. For the cups, there was no statistically significant TT or total rotation (TR) at 1–2 and 2–5 years. At 2–5 years, we found 4 cups and 5 stems with TT migrations exceeding the precision limit of the method. There was an association between cup migration and total OHS < 40 (4 patients, 4 hips; p = 0.04), but there were no statistically significant associations between cup or stem migration and T-scores < –1 (n = 10), cup and stem positions, or elevated serum metal ion levels (> 7µg/L (4 patients, 6 hips)). Interpretation Most cups and stems were well-fixed at 1–5 years. However, at 2–5 years, 4 cups and 5 stems had TT migrations above the precision limits, but these patients had serum metal ion levels similar to those of patients without measurable migrations, and they were pain-free. Patients with serum metal ion levels > 7 µg/L had migrations similar to those in patients with serum metal ion levels < 7 µg/L. Metal wear debris does not appear to influence the

  7. The influence of clearance on friction, lubrication and squeaking in large diameter metal-on-metal hip replacements.

    PubMed

    Brockett, Claire L; Harper, Phil; Williams, Sophie; Isaac, Graham H; Dwyer-Joyce, Rob S; Jin, Zhongmin; Fisher, John

    2008-04-01

    Large diameter metal-on-metal bearings (MOM) are becoming increasingly popular, addressing the needs of young and more active patients. Clinical data has shown excellent short-to-mid-term results, though incidences of transient squeaking have been noted between implantation and up to 2 years post-operative. Geometric design features, such as clearance, have been significant in influencing the performance of the bearings. Sets of MOM bearings with different clearances were investigated in this study using a hip friction simulator to examine the influence of clearance on friction, lubrication and squeaking. The friction factor was found to be highest in the largest clearance bearings under all test conditions. The incidence of squeaking was also highest in the large clearance bearings, with all bearings in this group squeaking throughout the study. A very low incidence of squeaking was observed in the other two clearance groups. The measured lubricating film was found to be lowest in the large clearance bearings. This study suggests that increasing the bearing clearance results in reduced lubricant film thickness, increased friction and an increased incidence of squeaking.

  8. Assessing the material loss of the modular taper interface in retrieved metal-on-metal hip replacements

    NASA Astrophysics Data System (ADS)

    Bills, Paul J.; Racasan, R.; Tessier, P.; Blunt, L. A.

    2015-06-01

    Measuring the amount of material loss in the case of revised hip replacements is considered to be a prerequisite of understanding and assessing the true in vivo performance of the implant. This paper outlines a method developed by the authors for quantifying taper material loss as well as more general taper interface parameters. Previous studies have mostly relied on visual inspection to assess the material loss at the taper interface, whereas this method aims to characterize any surface and form changes through the use of an out-of-roundness measurement machine. Along with assessing the volumetric wear, maximum linear penetration and taper contact length can also be determined. The method was applied to retrieved large head metal-on-metal femoral heads in order to quantify the material loss at this junction. Material loss from the female femoral head taper can be characterized as a localized area that is in contact with the stem taper surface. The study showed that this method has good repeatability and a low level of interoperability variation between operators.

  9. Have the media influenced the use of hip resurfacing arthroplasty? A review of UK print media

    PubMed Central

    Malviya, A; Stafford, GH; Villar, RJF; Villar, RN

    2012-01-01

    INTRODUCTION The aim of this study was to look at the different claims made about hip resurfacing arthroplasty in the popular UK print media and how this relates to findings in the scientific literature. METHODS A review of UK popular print media from January 1992 to June 2011 was performed using the Lexis® Library online news database. Only articles discussing the clinical results of hip resurfacing arthroplasty were included. After excluding duplicates, 49 newspaper articles were found suitable for this study. The main outcome measure was the claims made in popular UK print media about hip resurfacing. These were compared with the scientific publication. We reviewed the trend of use of hip resurfacing prostheses during the same period as reported in the National Joint Registry. RESULTS A disparity was found between the claims in the newspapers and published scientific literature. The initial newspaper articles highlighted only the positive aspects of hip resurfacing arthroplasty, without definitive contemporary evidence backing the claims. Most of these claims were refuted by future scientific publications. The initial positive media reports coincided with an increase in the use of hip resurfacing but the decline coincided with negative reports in the scientific literature. CONCLUSIONS The trend of the newspaper articles and that of the number of hip resurfacing prostheses implanted suggests that the media may have been partly responsible for the increased use of this prosthesis. The subsequent decrease was initiated by the scientific literature. PMID:22943335

  10. In vivo wear of three types of metal on metal hip prostheses during two decades of use.

    PubMed

    McKellop, H; Park, S H; Chiesa, R; Doorn, P; Lu, B; Normand, P; Grigoris, P; Amstutz, H

    1996-08-01

    Wear was analyzed on 21 metal on metal hip replacements, including McKee-Farrar, Müller, and Ring, that were retrieved from patients after as many as 25 years. Light and scanning electron microscopy indicated that early wear included substantial third body abrasion, possibly from particles generated while scratches from the original polishing were being eradicated and from dislodged surface carbides. However, the main contact zones were eventually worn smoother than the original surfaces. Wear was quantified by digitizing the shapes of the components on a coordinate measuring machine and identifying those areas that deviated from the original spheric surface. On the femoral heads, wear was typically concentrated in the superomedial region, that is, on the load axis. Three cases also had substantial wear inferiorly, but there were no cases with circumferential (equatorial) wear. The long term wear rates averaged approximately 6 micrometers per year or less and produced an average of approximately 6 mm3 of metallic wear debris per year or less. Wear rate tended to increase as clearance increased over the range of 127 to 386 micrometers, and a McKee-Farrar prosthesis with the extreme clearance of 1.7 mm wore approximately 16 times faster than the average, but there was no apparent relationship between clearance and time to revision. Larger McKee-Farrar balls had less volumetric wear, on average, than smaller balls, and the Müller balls had the greatest wear, which may have been due to contact with the edges of recesses machined into the bearing zones of the Müller cups. PMID:8769330

  11. Prediction of contact mechanics in metal-on-metal Total Hip Replacement for parametrically comprehensive designs and loads.

    PubMed

    Donaldson, Finn E; Nyman, Edward; Coburn, James C

    2015-07-16

    Manufacturers and investigators of Total Hip Replacement (THR) bearings require tools to predict the contact mechanics resulting from diverse design and loading parameters. This study provides contact mechanics solutions for metal-on-metal (MoM) bearings that encompass the current design space and could aid pre-clinical design optimization and evaluation. Stochastic finite element (FE) simulation was used to calculate the head-on-cup contact mechanics for five thousand combinations of design and loading parameters. FE results were used to train a Random Forest (RF) surrogate model to rapidly predict the contact patch dimensions, contact area, pressures and plastic deformations for arbitrary designs and loading. In addition to widely observed polar and edge contact, FE results included ring-polar, asymmetric-polar, and transitional categories which have previously received limited attention. Combinations of design and load parameters associated with each contact category were identified. Polar contact pressures were predicted in the range of 0-200 MPa with no permanent deformation. Edge loading (with subluxation) was associated with pressures greater than 500 MPa and induced permanent deformation in 83% of cases. Transitional-edge contact (with little subluxation) was associated with intermediate pressures and permanent deformation in most cases, indicating that, even with ideal anatomical alignment, bearings may face extreme wear challenges. Surrogate models were able to accurately predict contact mechanics 18,000 times faster than FE analyses. The developed surrogate models enable rapid prediction of MoM bearing contact mechanics across the most comprehensive range of loading and designs to date, and may be useful to those performing bearing design optimization or evaluation.

  12. Effect of microseparation on contact mechanics in metal-on-metal hip replacements-A finite element analysis.

    PubMed

    Liu, Feng; Williams, Sophie; Fisher, John

    2015-08-01

    Some early failures of metal-on-metal (MoM) hip replacements associated with elevated wear have caused concerns for the use of this bearing combination. Simulator studies have shown that microseparation and its associated rim contact and edge loading may produce the most severe wear in MoM bearings. It is generally recognized that this high wear can be attributed to the high contact stress of the head on the rim of the cup. In this study, an improved finite element contact model that incorporates an elastic-perfectly plastic material property for cobalt-chrome alloy of the metal bearing was developed in an attempt to provide an accurate prediction of the stress and strain for the rim contact. The effects of the microseparation displacement (0.1-2 mm), cup inclination angle (25-65°) and cup rim radius (0.5-4 mm) on the contact stress/strain were investigated. The results show that a translational displacement >0.1 mm under a load >0.5 kN can produce a highly concentrated contact stress at the surface of the cup rim which can lead to plastic deformation. This study also suggests that the magnitude of translational displacement was the major factor that determined the severity of the contact conditions and level of stress and strain under microseparation conditions. Future studies will address the effect of surgical translational and rotational malposition and component design on the magnitude of microseparation, contact stress and strain and severity of wear.

  13. Hip resurfacing after iliofemoral distraction for type IV developmental dysplasia of the hip a case report.

    PubMed

    Sambri, A; Cadossi, M; Mazzotti, A; Faldini, C; Giannini, S

    2015-01-01

    Osteoarthritis secondary to developmental dysplasia of the hip is a surgical challenge because of the modified anatomy of the acetabulum which is deficient in its shape with poor bone quality, torsional deformities of the femur and the altered morphology of femoral head. Particularly in Crowe type III and IV, additional surgical challenges are present, such as limb-length discrepancy and adductor muscle contractures. This is a bilateral hip dysplasia case where bilateral hip replacement was indicated, on the left side with a resurfacing one and on the other side a two stage procedure using a iliofemoral external fixator to restore equal leg length with a lower risk of complications. This case report shows both the negative clinical outcome of the left and the excellent one of the right hip where the dysplasia was much more severe. Patient selection and implant positioning are crucial in determining long-term results. PMID:27218252

  14. Hip resurfacing after iliofemoral distraction for type IV developmental dysplasia of the hip a case report.

    PubMed

    Sambri, A; Cadossi, M; Mazzotti, A; Faldini, C; Giannini, S

    2015-01-01

    Osteoarthritis secondary to developmental dysplasia of the hip is a surgical challenge because of the modified anatomy of the acetabulum which is deficient in its shape with poor bone quality, torsional deformities of the femur and the altered morphology of femoral head. Particularly in Crowe type III and IV, additional surgical challenges are present, such as limb-length discrepancy and adductor muscle contractures. This is a bilateral hip dysplasia case where bilateral hip replacement was indicated, on the left side with a resurfacing one and on the other side a two stage procedure using a iliofemoral external fixator to restore equal leg length with a lower risk of complications. This case report shows both the negative clinical outcome of the left and the excellent one of the right hip where the dysplasia was much more severe. Patient selection and implant positioning are crucial in determining long-term results.

  15. Hip resurfacing arthroplasty: A new method to assess and quantify learning phase.

    PubMed

    Aulakh, T S; Jayasekera, N; Singh, R; Patel, A; Kuiper, J H; Richardson, J B

    2014-09-01

    Hip resurfacing had initially gained acceptance and popularity as it helps preserve femoral bone stock. In this study we tried to answer the following questions; 1. Whether there is a learning curve for hip resurfacing? 2. Is it present in surgeons from non-developer centres? 3. Is it present in surgeons from developer centres as well? The Oswestry outcome centre was setup to serve an independent international registry for collecting, analysing and reporting outcomes following hip resurfacing. Over a 10 year period, 4535 patients (5000 hips) were recruited from different countries and within the UK from different centres in this study by 139 surgeons from 37 different countries. Our study has shown that function can be used to assess the level of surgical competence. The results from this multilevel analysis have helped to answer the questions posed in the introduction. Hip resurfacing is a surgical procedure with a learning phase and this learning effect is more pronounced in non-developer surgeons as compared to developer surgeons. Hip scores can be used to assess proficiency and competence of surgeons undertaking hip resurfacing arthroplasty.

  16. Cementless large-head metal-on-metal total hip arthroplasty in patients younger than 60 years--a multicenter early result.

    PubMed

    Wu, Po-Ting; Wang, Chih-Jen; Yen, Cheng-Yo; Jian, Ji-Shen; Lai, Kuo-An

    2012-01-01

    Large-head metal-on-metal total hip arthroplasty has the theoretical advantages of less wear and better range of motion than traditional polyethylene bearings and seems to be a better choice for young and active patients. We conducted a retrospective study and reported the early results of using such prostheses in 59 patients (70 hips) with a mean age of 43.1 years (range, 23-59 years) at the time of surgery. Osteonecrosis of the femoral head accounted for most diagnoses. Harris Hip Scores and hip range of motion both significantly improved (p<0.001) at an average follow-up of 32.6 months (range, 24-48 months). Only one intraoperative calcar fissure was encountered, and it was fixated by cerclage wiring; there was no infection, dislocation, or osteolysis around either the cup or the stem at the latest follow-up. A postoperative gap in the acetabular component was noted in 24 hips, with a mean depth of 1.11 mm, but this was not correlated with the functional score (p=0.291). Transient thigh pain, which resolved after 6 months, was observed in six patients but was not related to either the postoperative gap or cup inclination (p=1.000 and p=0.664, respectively). All patients resumed their original jobs and recreational activities with little discomfort. Thus far, large-head metal-on-metal total hip arthroplasty has shown excellent early results. The long-term results and the effects of metal debris and potentially elevated serum metal ion levels require further observation.

  17. N-Acetyl-Cysteine as Effective and Safe Chelating Agent in Metal-on-Metal Hip-Implanted Patients: Two Cases

    PubMed Central

    Lonati, Davide; Ragghianti, Benedetta; Ronchi, Anna; Vecchio, Sarah; Locatelli, Carlo Alessandro

    2016-01-01

    Systemic toxicity associated with cobalt (Co) and chromium (Cr) containing metal hip alloy may result in neuropathy, cardiomyopathy, and hypothyroidism. However clinical management concerning chelating therapy is still debated in literature. Here are described two metal-on-metal hip-implanted patients in which N-acetyl-cysteine decreased elevated blood metal levels. A 67-year-old male who underwent Co/Cr hip implant in September 2009 referred to our Poison Control Centre for persisting elevated Co/Cr blood levels (from March 2012 to November 2014). After receiving oral high-dose N-acetyl-cysteine, Co/Cr blood concentrations dropped by 86% and 87% of the prechelation levels, respectively, and persisted at these latter concentrations during the following 6 months of follow-up. An 81-year-old female who underwent Co/Cr hip implant in January 2007 referred to our Centre for detection of high Co and Cr blood levels in June 2012. No hip revision was indicated. After a therapy with oral high-dose N-acetyl-cysteine Co/Cr blood concentrations decreased of 45% and 24% of the prechelation levels. Chelating agents reported in hip-implanted patients (EDTA, DMPS, and BAL) are described in few cases. N-acetyl-cysteine may provide chelating sites for metals and in our cases reduced Co and Cr blood levels and resulted well tolerable. PMID:27148463

  18. Steady-state elastohydrodynamic lubrication analysis of a metal-on-metal hip implant employing a metallic cup with an ultra-high molecular weight polyethylene backing.

    PubMed

    Liu, F; Wang, F C; Jin, Z M; Hirt, F; Rieker, C; Grigoris, P

    2004-01-01

    The elastohydrodynamic lubrication (EHL) analysis was carried out in this study for a 28 mm diameter metal-on-metal hip prosthesis employing a metallic cup with an ultra-high molecular weight polyethylene (UHMWPE) backing under a simple steady state rotation representing the flexion/extension during walking. Both Reynolds and elasticity equations were coupled and solved numerically by the finite difference method. The elastic deformation was determined by means of the fast Fourier transform (FFT) technique using the displacement coefficients obtained from the finite element method. Excellent agreement of the predicted elastic deformation was obtained between the FFT technique and the conventional direct summation method. The number of grid points used in the lubrication analysis was found to be important in predicting accurate film thicknesses, particularly at low viscosities representative of physiological lubricants. The effect of the clearance between the femoral head and the acetabular cup on the predicted lubricant film thickness was shown to be significant, while the effect of load was found to be negligible. Overall, the UHMWPE backing was found not only to reduce the contact pressure as identified in a previous study by the authors (Liu et al., 2003) but also significantly to increase the lubricant film thickness for the 28 mm diameter metal-on-metal hip implant, as compared with a metallic mono-block cup.

  19. Distributed Analysis of Hip Implants Using Six National and Regional Registries: Comparing Metal-on-Metal with Metal-on-Highly Cross-Linked Polyethylene Bearings in Cementless Total Hip Arthroplasty in Young Patients

    PubMed Central

    Furnes, Ove; Paxton, Elizabeth; Cafri, Guy; Graves, Stephen; Bordini, Barbara; Comfort, Thomas; Rivas, Moises Coll; Banerjee, Samprit; Sedrakyan, Art

    2014-01-01

    Background: The regulation of medical devices has attracted controversy recently because of problems related to metal-on-metal hip implants. There is growing evidence that metal-on-metal implants fail early and cause local and systemic complications. However, the failure associated with metal-on-metal head size is not consistently documented and needs to be communicated to patients and surgeons. The purpose of this study is to compare implant survival of metal on metal with that of metal on highly cross-linked polyethylene. Methods: Using a distributed health data network, primary total hip arthroplasties were identified from six national and regional total joint arthroplasty registries (2001 to 2010). Inclusion criteria were patient age of forty-five to sixty-four years, cementless total hip arthroplasties, primary osteoarthritis diagnosis, and exclusion of the well-known outlier implant ASR (articular surface replacement). The primary outcome was revision for any reason. A meta-analysis of survival probabilities was performed with use of a fixed-effects model. Metal-on-metal implants with a large head size of >36 mm were compared with metal-on-highly cross-linked polyethylene implants. Results: Metal-on-metal implants with a large head size of >36 mm were used in 5172 hips and metal-on-highly cross-linked polyethylene implants were used in 14,372 hips. Metal-on-metal total hip replacements with a large head size of >36 mm had an increased risk of revision compared with metal-on-highly cross-linked polyethylene total hip replacements with more than two years of follow-up, with no difference during the first two years after implantation. The results of the hazard ratios (and 95% confidence intervals) from the multivariable model at various durations of follow-up were 0.95 (0.74 to 1.23) at zero to two years (p = 0.698), 1.42 (1.16 to 1.75) at more than two years to four years (p = 0.001), 1.78 (1.45 to 2.19) at more than four years to six years (p < 0.001), and 2

  20. A longitudinal study of MARS MRI scanning of soft-tissue lesions around metal-on-metal total hip arthroplasties and disease progression.

    PubMed

    Briant-Evans, T W; Lyle, N; Barbur, S; Hauptfleisch, J; Amess, R; Pearce, A R; Conn, K S; Stranks, G J; Britton, J M

    2015-10-01

    We investigated the changes seen on serial metal artefact reduction magnetic resonance imaging scans (MARS-MRI) of metal-on-metal total hip arthroplasties (MoM THAs). In total 155 THAs, in 35 male and 100 female patients (mean age 70.4 years, 42 to 91), underwent at least two MRI scans at a mean interval of 14.6 months (2.6 to 57.1), at a mean of 48.2 months (3.5 to 93.3) after primary hip surgery. Scans were graded using a modification of the Oxford classification. Progression of disease was defined as an increase in grade or a minimum 10% increase in fluid lesion volume at second scan. A total of 16 hips (30%) initially classified as 'normal' developed an abnormality on the second scan. Of those with 'isolated trochanteric fluid' 9 (47%) underwent disease progression, as did 7 (58%) of 'effusions'. A total of 54 (77%) of hips initially classified as showing adverse reactions to metal debris (ARMD) progressed, with higher rates of progression in higher grades. Disease progression was associated with high blood cobalt levels or an irregular pseudocapsule lining at the initial scan. There was no association with changes in functional scores. Adverse reactions to metal debris in MoM THAs may not be as benign as previous reports have suggested. Close radiological follow-up is recommended, particularly in high-risk groups. PMID:26430006

  1. A longitudinal study of MARS MRI scanning of soft-tissue lesions around metal-on-metal total hip arthroplasties and disease progression.

    PubMed

    Briant-Evans, T W; Lyle, N; Barbur, S; Hauptfleisch, J; Amess, R; Pearce, A R; Conn, K S; Stranks, G J; Britton, J M

    2015-10-01

    We investigated the changes seen on serial metal artefact reduction magnetic resonance imaging scans (MARS-MRI) of metal-on-metal total hip arthroplasties (MoM THAs). In total 155 THAs, in 35 male and 100 female patients (mean age 70.4 years, 42 to 91), underwent at least two MRI scans at a mean interval of 14.6 months (2.6 to 57.1), at a mean of 48.2 months (3.5 to 93.3) after primary hip surgery. Scans were graded using a modification of the Oxford classification. Progression of disease was defined as an increase in grade or a minimum 10% increase in fluid lesion volume at second scan. A total of 16 hips (30%) initially classified as 'normal' developed an abnormality on the second scan. Of those with 'isolated trochanteric fluid' 9 (47%) underwent disease progression, as did 7 (58%) of 'effusions'. A total of 54 (77%) of hips initially classified as showing adverse reactions to metal debris (ARMD) progressed, with higher rates of progression in higher grades. Disease progression was associated with high blood cobalt levels or an irregular pseudocapsule lining at the initial scan. There was no association with changes in functional scores. Adverse reactions to metal debris in MoM THAs may not be as benign as previous reports have suggested. Close radiological follow-up is recommended, particularly in high-risk groups.

  2. Does surface wettability influence the friction and wear of large-diameter CoCrMo alloy hip resurfacings?

    PubMed

    Curran, Sarah; Hoskin, Tom; Williams, Sarah; Scholes, Susan C; Kinbrum, Amy; Unsworth, Anthony

    2013-08-01

    The role of surface tension in the lubrication of metal-on-metal (CoCrMo alloy) hip resurfacings has been investigated to try to explain why all metal joints fail to be lubricated with simple water-based lubricants (sodium carboxymethyl cellulose), which have similar rheology to synovial fluid, but are lubricated with the same fluid with the addition of a proportion of bovine serum. As part of this study, surfactants, in the form of detergents, when added to carboxymethyl cellulose, have been shown to produce a predominantly fluid-film lubrication mechanism with friction even lower than the biological lubricant containing serum. Friction factors were reduced by 80% when a detergent was added to the lubricant. It is considered that the failure of the water-based fluids to generate fluid-film lubrication is due to the fact that 'boundary slip' takes place where the fluid does not fully attach to the bounding solid surfaces as assumed in Reynolds' equation, thereby drawing in less lubricant than predicted from hydrodynamic theory. The addition of surfactants either in the form of natural materials such as serum or in the form of detergent reduces surface tension and helps the water-based lubricant to attach more fully to the bounding surfaces resulting in more fluid entrainment and thicker fluid-film formation. This was confirmed by up to 70% lower wear being found when these joints were lubricated in a detergent solution rather than 25% bovine serum.

  3. Does surface wettability influence the friction and wear of large-diameter CoCrMo alloy hip resurfacings?

    PubMed

    Curran, Sarah; Hoskin, Tom; Williams, Sarah; Scholes, Susan C; Kinbrum, Amy; Unsworth, Anthony

    2013-08-01

    The role of surface tension in the lubrication of metal-on-metal (CoCrMo alloy) hip resurfacings has been investigated to try to explain why all metal joints fail to be lubricated with simple water-based lubricants (sodium carboxymethyl cellulose), which have similar rheology to synovial fluid, but are lubricated with the same fluid with the addition of a proportion of bovine serum. As part of this study, surfactants, in the form of detergents, when added to carboxymethyl cellulose, have been shown to produce a predominantly fluid-film lubrication mechanism with friction even lower than the biological lubricant containing serum. Friction factors were reduced by 80% when a detergent was added to the lubricant. It is considered that the failure of the water-based fluids to generate fluid-film lubrication is due to the fact that 'boundary slip' takes place where the fluid does not fully attach to the bounding solid surfaces as assumed in Reynolds' equation, thereby drawing in less lubricant than predicted from hydrodynamic theory. The addition of surfactants either in the form of natural materials such as serum or in the form of detergent reduces surface tension and helps the water-based lubricant to attach more fully to the bounding surfaces resulting in more fluid entrainment and thicker fluid-film formation. This was confirmed by up to 70% lower wear being found when these joints were lubricated in a detergent solution rather than 25% bovine serum. PMID:23852389

  4. Prevalence of Pseudotumor in Patients After Metal-On-Metal Hip Arthroplasty Evaluated with Metal Ion Analysis and MARS-MRI.

    PubMed

    Sutphen, Sean A; MacLaughlin, Lewis H; Madsen, Adam A; Russell, Jackie H; McShane, Michael A

    2016-01-01

    The purpose of this study is to quantify the prevalence of pseudotumors in patients with well-functioning and painful metal-on-metal total hip arthroplasty, to characterize the pseudotumor with the use of MARS-MRI, and to assess the relationship between pseudotumors and metal ions. We retrospectively reviewed 102 single surgeon patients. The results showed that 68.6% developed pseudotumor with 60.9% of the asymptomatic group developing pseudotumor. The symptomatic group had a higher proportion of patients with elevated serum cobalt levels (P=0.035). There was no difference found with elevated metal ions and prevalence of pseudotumor, but elevated cobalt levels were associated with larger pseudotumor size (P=0.001). The available evidence indicated that most patients that develop pseudotumors are asymptomatic, and that elevated serum cobalt levels may be associated with symptoms and pseudotumor size. PMID:26253484

  5. Prevalence of Pseudotumor in Patients After Metal-On-Metal Hip Arthroplasty Evaluated with Metal Ion Analysis and MARS-MRI.

    PubMed

    Sutphen, Sean A; MacLaughlin, Lewis H; Madsen, Adam A; Russell, Jackie H; McShane, Michael A

    2016-01-01

    The purpose of this study is to quantify the prevalence of pseudotumors in patients with well-functioning and painful metal-on-metal total hip arthroplasty, to characterize the pseudotumor with the use of MARS-MRI, and to assess the relationship between pseudotumors and metal ions. We retrospectively reviewed 102 single surgeon patients. The results showed that 68.6% developed pseudotumor with 60.9% of the asymptomatic group developing pseudotumor. The symptomatic group had a higher proportion of patients with elevated serum cobalt levels (P=0.035). There was no difference found with elevated metal ions and prevalence of pseudotumor, but elevated cobalt levels were associated with larger pseudotumor size (P=0.001). The available evidence indicated that most patients that develop pseudotumors are asymptomatic, and that elevated serum cobalt levels may be associated with symptoms and pseudotumor size.

  6. Validation of primary metal-on-metal hip arthroplasties on the National Joint Registry for England, Wales and Northern Ireland using data from the London Implant Retrieval Centre

    PubMed Central

    Sabah, S. A.; Henckel, J.; Cook, E.; Whittaker, R.; Hothi, H.; Pappas, Y.; Blunn, G.; Skinner, J. A.; Hart, A. J.

    2015-01-01

    Arthroplasty registries are important for the surveillance of joint replacements and the evaluation of outcome. Independent validation of registry data ensures high quality. The ability for orthopaedic implant retrieval centres to validate registry data is not known. We analysed data from the National Joint Registry for England, Wales and Northern Ireland (NJR) for primary metal-on-metal hip arthroplasties performed between 2003 and 2013. Records were linked to the London Implant Retrieval Centre (RC) for validation. A total of 67 045 procedures on the NJR and 782 revised pairs of components from the RC were included. We were able to link 476 procedures (60.9%) recorded with the RC to the NJR successfully. However, 306 procedures (39.1%) could not be linked. The outcome recorded by the NJR (as either revised, unrevised or death) for a primary procedure was incorrect in 79 linked cases (16.6%). The rate of registry-retrieval linkage and correct assignment of outcome code improved over time. The rates of error for component reference numbers on the NJR were as follows: femoral head category number 14/229 (5.0%); femoral head batch number 13/232 (5.3%); acetabular component category number 2/293 (0.7%) and acetabular component batch number 24/347 (6.5%). Registry-retrieval linkage provided a novel means for the validation of data, particularly for component fields. This study suggests that NJR reports may underestimate rates of revision for many types of metal-on-metal hip replacement. This is topical given the increasing scope for NJR data. We recommend a system for continuous independent evaluation of the quality and validity of NJR data. Cite this article: Bone Joint J 2015;97-B:10–18. PMID:25568407

  7. CoCr wear particles generated from CoCr alloy metal-on-metal hip replacements, and cobalt ions stimulate apoptosis and expression of general toxicology-related genes in monocyte-like U937 cells.

    PubMed

    Posada, Olga M; Gilmour, Denise; Tate, Rothwelle J; Grant, M Helen

    2014-11-15

    Cobalt-chromium (CoCr) particles in the nanometre size range and their concomitant release of Co and Cr ions into the patients' circulation are produced by wear at the articulating surfaces of metal-on-metal (MoM) implants. This process is associated with inflammation, bone loss and implant loosening and led to the withdrawal from the market of the DePuy ASR™ MoM hip replacements in 2010. Ions released from CoCr particles derived from a resurfacing implant in vitro and their subsequent cellular up-take were measured by ICP-MS. Moreover, the ability of such metal debris and Co ions to induce both apoptosis was evaluated with both FACS and immunoblotting. qRT-PCR was used to assess the effects on the expression of lymphotoxin alpha (LTA), BCL2-associated athanogene (BAG1), nitric oxide synthase 2 inducible (NOS2), FBJ murine osteosarcoma viral oncogene homolog (FOS), growth arrest and DNA-damage-inducible alpha (GADD45A). ICP-MS showed that the wear debris released significant (p<0.05) amounts of Co and Cr ions into the culture medium, and significant (p<0.05) cellular uptake of both ions. There was also an increase (p<0.05) in apoptosis after a 48h exposure to wear debris. Analysis of qRT-PCR results found significant up-regulation (p<0.05) particularly of NOS2 and BAG1 in Co pre-treated cells which were subsequently exposed to Co ions+debris. Metal debris was more effective as an inducer of apoptosis and gene expression when cells had been pre-treated with Co ions. This suggests that if a patient receives sequential bilateral CoCr implants, the second implant may be more likely to produce adverse effects than the first one. PMID:25281833

  8. Gluteal muscle fatty atrophy is not associated with elevated blood metal ions or pseudotumors in patients with a unilateral metal-on-metal hip replacement

    PubMed Central

    Reito, Aleksi; Elo, Petra; Nieminen, Jyrki; Puolakka, Timo; Eskelinen, Antti

    2016-01-01

    Background and purpose There are no international guidelines to define adverse reaction to metal debris (ARMD). Muscle fatty atrophy has been reported to be common in patients with failing metal-on-metal (MoM) hip replacements. We assessed whether gluteal muscle fatty atrophy is associated with elevated blood metal ion levels and pseudotumors. Patients and methods 263 consecutive patients with unilateral ASR XL total hip replacement using a posterior approach and with an unoperated contralateral hip were included in the study. All patients had undergone a standard screening program at our institution, including MRI and blood metal ion measurement. Muscle fatty atrophy was graded as being absent, mild, moderate, or severe in each of the gluteal muscles. Results The prevalance of moderate-to-severe gluteal muscle atrophy was low (12% for gluteus minimus, 10% for gluteus medius, and 2% for gluteus maximus). Muscle atrophy was neither associated with elevated blood metal ion levels (> 5 ppb) nor with the presence of a clear (solid- or mixed-type) pseudotumor seen in MRI. A combination of moderate-to-severe atrophy in MRI, elevated blood metal ion levels, and MRI-confirmed mixed or solid pseudotumor was rare. Multivariable regression revealed that “preoperative diagnosis other than osteoarthrosis” was the strongest predictor of the presence of fatty atrophy. Interpretation Gluteal muscle atrophy may be a clinically significant finding with influence on hip muscle strength in patients with MoM hip replacement. However, our results suggest that gluteal muscle atrophy seen in MRI is not associated with either the presence or severity of ARMD, at least not in patients who have been operated on using the posterior approach. PMID:26427902

  9. A simulator study of adverse wear with metal and cement debris contamination in metal-on-metal hip bearings

    PubMed Central

    Halim, T.; Clarke, I. C.; Burgett-Moreno, M. D.; Donaldson, T. K.; Savisaar, C.; Bowsher, J. G.

    2015-01-01

    Objectives Third-body wear is believed to be one trigger for adverse results with metal-on-metal (MOM) bearings. Impingement and subluxation may release metal particles from MOM replacements. We therefore challenged MOM bearings with relevant debris types of cobalt–chrome alloy (CoCr), titanium alloy (Ti6Al4V) and polymethylmethacrylate bone cement (PMMA). Methods Cement flakes (PMMA), CoCr and Ti6Al4V particles (size range 5 µm to 400 µm) were run in a MOM wear simulation. Debris allotments (5 mg) were inserted at ten intervals during the five million cycle (5 Mc) test. Results In a clean test phase (0 Mc to 0.8 Mc), lubricants retained their yellow colour. Addition of metal particles at 0.8 Mc turned lubricants black within the first hour of the test and remained so for the duration, while PMMA particles did not change the colour of the lubricant. Rates of wear with PMMA, CoCr and Ti6Al4V debris averaged 0.3 mm3/Mc, 4.1 mm3/Mc and 6.4 mm3/Mc, respectively. Conclusions Metal particles turned simulator lubricants black with rates of wear of MOM bearings an order of magnitude higher than with control PMMA particles. This appeared to model the findings of black, periarticular joint tissues and high CoCr wear in failed MOM replacements. The amount of wear debris produced during a 500 000-cycle interval of gait was 30 to 50 times greater than the weight of triggering particle allotment, indicating that MOM bearings were extremely sensitive to third-body wear. Cite this article: Bone Joint Res 2015;4:29–37. PMID:25736072

  10. Poor mid-term survival of the low-carbide metal-on-metal Zweymüller-plus total hip arthroplasty system: a concise follow-up, at a minimum of ten years, of a previous report*.

    PubMed

    Repantis, Thomas; Vitsas, Vasilis; Korovessis, Panagiotis

    2013-03-20

    Between 1994 and 1999, 217 metal-on-metal total hip arthroplasties with a low-carbide bearing surface were performed with use of the cementless Zweymüller SL-Plus stem and the Bicon-Plus threaded cup in 194 consecutive patients. After a minimum follow-up of ten years, 181 living patients (203 hips) were available for evaluation. The revision rate after an average of twelve years was 18% (thirty-six hips in thirty-six patients were revised). The main reason for revision was aseptic loosening of one or both components. The probability of survival of the stem at fifteen years was 77% (95% confidence interval [CI], 65% to 86%). The probability of survival of the cup was 80% (95% CI, 62% to 90%). These high failure rates at mid-term follow-up led us to abandon the use of low-carbide metal-on-metal total hip arthroplasty components. PMID:23515994

  11. 21 CFR 888.3410 - Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing 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 metal/polymer or ceramic/polymer... Devices § 888.3410 Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis. (a) Identification. A hip joint metal/polymer or ceramic/polymer semi-constrained...

  12. 21 CFR 888.3410 - Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing 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 metal/polymer or ceramic/polymer... Devices § 888.3410 Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis. (a) Identification. A hip joint metal/polymer or ceramic/polymer semi-constrained...

  13. 21 CFR 888.3410 - Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing 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 metal/polymer or ceramic/polymer... Devices § 888.3410 Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis. (a) Identification. A hip joint metal/polymer or ceramic/polymer semi-constrained...

  14. 21 CFR 888.3410 - Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing 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 metal/polymer or ceramic/polymer... Devices § 888.3410 Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis. (a) Identification. A hip joint metal/polymer or ceramic/polymer semi-constrained...

  15. 21 CFR 888.3410 - Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing 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 metal/polymer or ceramic/polymer... Devices § 888.3410 Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis. (a) Identification. A hip joint metal/polymer or ceramic/polymer semi-constrained...

  16. Influence of particulate and dissociated metal-on-metal hip endoprosthesis wear on mesenchymal stromal cells in vivo and in vitro.

    PubMed

    Rakow, Anastasia; Schoon, Janosch; Dienelt, Anke; John, Thilo; Textor, Martin; Duda, Georg; Perka, Carsten; Schulze, Frank; Ode, Andrea

    2016-08-01

    In hip arthroplasty the implants' articulating surfaces can be made of a cobalt-chromium-molybdenum (CoCrMo) alloy. The use of these metal-on-metal (MoM) pairings can lead to the release of wear products such as metallic particles and dissociated metal species, raising concerns regarding their safety amongst orthopedic surgeons and the public. MoM-wear particles are reported to be heterogeneous in their physicochemical properties, are capable of inducing adverse effects on a cellular level and are thought to be involved in relevant clinical problems like aseptic osteolysis. Yet, it remains elusive how MoM-wear affects bone forming cells and their progenitors: bone marrow residing mesenchymal stromal cells (MSCs). This study introduces an assessment of the in vivo exposure to particulate and dissociated Co and Cr and evaluates the effects of MoM-wear on MSCs. The exposure to MoM-wear products in vivo and in vitro leads to a decrease in MSCs' osteogenic matrix mineralization and alkaline phosphatase activity on a cellular and systemic level. In conclusion, MoM-wear products are released in the periprosthetic region and elevate bone marrow Co and Cr concentrations towards levels that impair osteogenic differentiation of MSCs. Therefore, the ongoing use of CoCrMo alloys for articulating surfaces in joint replacement implants needs critical reconsideration. PMID:27179133

  17. Clinical outcome study and radiological findings of Zweymuller metal on metal total hip arthroplasty. a follow-up of 6 to 15 years.

    PubMed

    Paleochorlidis, Ilias S; Badras, Leonidas S; Skretas, Efstathios F; Georgaklis, Vasilios A; Karachalios, Theofilos S; Malizos, Konstantinos N

    2009-01-01

    We report the clinical and radiological outcome of 99 Zweymuller metal on metal total hip arthroplasties in 84 patients followed up prospectively for a mean period of 9.5 (range, 6-15) years. There were 29 (34.5%) male and 55 (65.5%) female patients with a mean age of 62.85 years (range, 50-70 years) at the time of surgery. All patients had osteoarthritis. One acetabular component and one stem were revised due to aseptic loosening. One femoral stem was revised due to a periprosthetic fracture. HHS score improved from a preoperative mean of 62.56 points (SD 8.87) to a final postoperative follow-up mean of 93.48 (SD 7.7). Cumulative success rate for both implants at 13 years, with aseptic loosening as the end point, was 97.05%, while for both implants at 13 years, with revision for any reason as the end point, it was 91.17%. Satisfactory results were observed with the use of this prosthesis. PMID:20041375

  18. Accuracy of methods for calculating volumetric wear from coordinate measuring machine data of retrieved metal-on-metal hip joint implants.

    PubMed

    Lu, Zhen; McKellop, Harry A

    2014-03-01

    This study compared the accuracy and sensitivity of several numerical methods employing spherical or plane triangles for calculating the volumetric wear of retrieved metal-on-metal hip joint implants from coordinate measuring machine measurements. Five methods, one using spherical triangles and four using plane triangles to represent the bearing and the best-fit surfaces, were assessed and compared on a perfect hemisphere model and a hemi-ellipsoid model (i.e. unworn models), computer-generated wear models and wear-tested femoral balls, with point spacings of 0.5, 1, 2 and 3 mm. The results showed that the algorithm (Method 1) employing spherical triangles to represent the bearing surface and to scale the mesh to the best-fit surfaces produced adequate accuracy for the wear volume with point spacings of 0.5, 1, 2 and 3 mm. The algorithms (Methods 2-4) using plane triangles to represent the bearing surface and to scale the mesh to the best-fit surface also produced accuracies that were comparable to that with spherical triangles. In contrast, if the bearing surface was represented with a mesh of plane triangles and the best-fit surface was taken as a smooth surface without discretization (Method 5), the algorithm produced much lower accuracy with a point spacing of 0.5 mm than Methods 1-4 with a point spacing of 3 mm. PMID:24531891

  19. In vitro analysis of the wear, wear debris and biological activity of surface-engineered coatings for use in metal-on-metal total hip replacements.

    PubMed

    Williams, S; Tipper, J L; Ingham, E; Stone, M H; Fisher, J

    2003-01-01

    Extremely low wear rates have been reported for metal-on-metal total hip replacements, but concerns remain about the effects of metal ion release, dissolution rates and toxicity. Surface-engineered coatings have the potential to improve wear resistance and reduce the biological activity of the wear debris produced. The aim of this study was to examine the wear and wear debris generation from surface-engineered coatings: titanium nitride (TiN), chromium nitride (CrN) and chromium carbon nitride (CrCN) applied to a cobalt-chrome alloy (CoCr) substrate. The coatings were articulated against themselves in a simple geometry model. The wear particles generated were characterized and the cytotoxic effect on U937 macrophages and L929 fibroblasts assessed. The CrN and CrCN coatings showed a decrease in wear compared to the CoCr bearings and produced small (less than 40 nm in length) wear particles. The wear particles released from the surface engineered bearings also showed a decreased cytotoxic effect on cells compared to the CoCr alloy debris. The reduced wear volumes coupled with the reduced cytotoxicity per unit volume of wear indicate the potential for the clinical application of this technology.

  20. Accuracy of methods for calculating volumetric wear from coordinate measuring machine data of retrieved metal-on-metal hip joint implants.

    PubMed

    Lu, Zhen; McKellop, Harry A

    2014-03-01

    This study compared the accuracy and sensitivity of several numerical methods employing spherical or plane triangles for calculating the volumetric wear of retrieved metal-on-metal hip joint implants from coordinate measuring machine measurements. Five methods, one using spherical triangles and four using plane triangles to represent the bearing and the best-fit surfaces, were assessed and compared on a perfect hemisphere model and a hemi-ellipsoid model (i.e. unworn models), computer-generated wear models and wear-tested femoral balls, with point spacings of 0.5, 1, 2 and 3 mm. The results showed that the algorithm (Method 1) employing spherical triangles to represent the bearing surface and to scale the mesh to the best-fit surfaces produced adequate accuracy for the wear volume with point spacings of 0.5, 1, 2 and 3 mm. The algorithms (Methods 2-4) using plane triangles to represent the bearing surface and to scale the mesh to the best-fit surface also produced accuracies that were comparable to that with spherical triangles. In contrast, if the bearing surface was represented with a mesh of plane triangles and the best-fit surface was taken as a smooth surface without discretization (Method 5), the algorithm produced much lower accuracy with a point spacing of 0.5 mm than Methods 1-4 with a point spacing of 3 mm.

  1. Asymptomatic prospective and retrospective cohorts with metal-on-metal hip arthroplasty indicate acquired lymphocyte reactivity varies with metal ion levels on a group basis.

    PubMed

    Hallab, Nadim J; Caicedo, Marco; McAllister, Kyron; Skipor, Anastasia; Amstutz, Harlan; Jacobs, Joshua J

    2013-02-01

    Some tissues from metal-on-metal (MoM) hip arthroplasty revisions have shown evidence of adaptive-immune reactivity (i.e., excessive peri-implant lymphocyte infiltration/activation). We hypothesized that, prior to symptoms, some people with MoM hip arthroplasty will develop quantifiable metal-induced lymphocyte reactivity responses related to peripheral metal ion levels. We tested three cohorts (Group 1: n = 21 prospective longitudinal MoM hip arthroplasty; Group 2: n = 17 retrospective MoM hip arthroplasty; and Group 3: n = 20 controls without implants). We compared implant position, metal-ion release, and immuno-reactivity. MoM cohorts had elevated (p < 0.01) amounts of serum Co and Cr compared to controls as early as 3 months post-op (Group 1:1.2 ppb Co, 1.5 ppb Cr; Group 2: 3.4 ppb Co, 5.4 ppb Cr; Group 3: 0.01 ppb Co, 0.1 ppb Cr). However, only after 1-4 years post-op did 56% of Group 1 develop metal-reactivity (vs. 5% pre-op, metal-LTT, SI > 2), compared with 76% of Group 2, and 15% of Group 3 controls (patch testing was a poor diagnostic indicator with only 1/21 Group 1 positive). Higher cup-abduction angles (50° vs. 40°) in Group 1 were associated with higher serum Cr (p < 0.07). However, sub-optimal cup-anteversion angles (9° vs. 20°) had higher serum Co (p < 0.08). Serum Cr and Co were significantly elevated in reactive versus non-reactive Group-1 participants (p < 0.04). CD4+CD69+ T-helper lymphocytes (but not CD8+) and IL-1β, IL-12, and IL-6 cytokines were all significantly elevated in metal-reactive versus non-reactive Group 1 participants. Our results showed that lymphocyte reactivity to metals can develop within the first 1-4 years after MoM arthroplasty in asymptomatic patients and lags increases in metal ion levels. This increased metal reactivity was more prevalent in those individuals with extreme cup angles and higher amounts of circulating metal.

  2. CoCr wear particles generated from CoCr alloy metal-on-metal hip replacements, and cobalt ions stimulate apoptosis and expression of general toxicology-related genes in monocyte-like U937 cells

    SciTech Connect

    Posada, Olga M.; Gilmour, Denise; Tate, Rothwelle J.; Grant, M. Helen

    2014-11-15

    Cobalt-chromium (CoCr) particles in the nanometre size range and their concomitant release of Co and Cr ions into the patients' circulation are produced by wear at the articulating surfaces of metal-on-metal (MoM) implants. This process is associated with inflammation, bone loss and implant loosening and led to the withdrawal from the market of the DePuy ASR™ MoM hip replacements in 2010. Ions released from CoCr particles derived from a resurfacing implant in vitro and their subsequent cellular up-take were measured by ICP-MS. Moreover, the ability of such metal debris and Co ions to induce both apoptosis was evaluated with both FACS and immunoblotting. qRT-PCR was used to assess the effects on the expression of lymphotoxin alpha (LTA), BCL2-associated athanogene (BAG1), nitric oxide synthase 2 inducible (NOS2), FBJ murine osteosarcoma viral oncogene homolog (FOS), growth arrest and DNA-damage-inducible alpha (GADD45A). ICP-MS showed that the wear debris released significant (p < 0.05) amounts of Co and Cr ions into the culture medium, and significant (p < 0.05) cellular uptake of both ions. There was also an increase (p < 0.05) in apoptosis after a 48 h exposure to wear debris. Analysis of qRT-PCR results found significant up-regulation (p < 0.05) particularly of NOS2 and BAG1 in Co pre-treated cells which were subsequently exposed to Co ions + debris. Metal debris was more effective as an inducer of apoptosis and gene expression when cells had been pre-treated with Co ions. This suggests that if a patient receives sequential bilateral CoCr implants, the second implant may be more likely to produce adverse effects than the first one. - Highlights: • Effects of CoCr nanoparticles and Co ions on U937 cells were investigated. • Ions released from wear debris play an important role in cellular response, • Toxicity of Co ions could be related to NO metabolic processes and apoptosis. • CoCr particles were a more effective inducer of apoptosis after cell

  3. The clinical implications of elevated blood metal ion concentrations in asymptomatic patients with MoM hip resurfacings: a cohort study

    PubMed Central

    Langton, David J; Sidaginamale, Raghavendra P; Joyce, Thomas J; Natu, Shonali; Blain, Peter; Jefferson, Robert Drysdale; Rushton, Stephen; Nargol, Antoni V F

    2013-01-01

    Objective To determine whether elevated blood cobalt (Co) concentrations are associated with early failure of metal-on-metal (MoM) hip resurfacings secondary to adverse reaction to metal debris (ARMD). Design Cohort study. Setting Single centre orthopaedic unit. Participants Following the identification of complications potentially related to metal wear debris, a blood metal ion screening programme was instigated at our unit in 2007 for all patients with Articular Surface Replacement (ASR) and Birmingham MoM hip resurfacings. Patients were followed annually unless symptoms presented earlier. Symptomatic patients were investigated with ultrasound scan and joint aspiration. The clinical course of all 278 patients with ‘no pain’ or ‘slight/occasional’ pain and a Harris Hip Score greater than or equal to 95 at the time of venesection were documented. A retrospective analysis was subsequently conducted using mixed effect modelling to investigate the temporal pattern of blood Co levels in the patients and survival analysis to investigate the potential role of case demographics and blood Co levels as risk factors for subsequent failure secondary to ARMD. Results Blood Co concentration was a positive and significant risk factor (z=8.44, p=2×10–16) for joint failure, as was the device, where the Birmingham Hip Resurfacing posed a significantly reduced risk for revision by 89% (z=−3.445, p=0.00005 (95% CI on risk 62 to 97)). Analysis using Cox-proportional hazards models indicated that men had a 66% lower risk of joint failure than women (z=−2.29419, p=0.0218, (95% CI on risk reduction 23 to 89)). Conclusions The results suggest that elevated blood metal ion concentrations are associated with early failure of MoM devices secondary to adverse reactions to metal debris. Co concentrations greater than 20 µg/l are frequently associated with metal staining of tissues and the development of osteolysis. Development of soft tissue damage appears to be more complex

  4. An in vitro study of the reduction in wear of metal-on-metal hip prostheses using surface-engineered femoral heads.

    PubMed

    Fisher, J; Hu, X Q; Tipper, J L; Stewart, T D; Williams, S; Stone, M H; Davies, C; Hatto, P; Bolton, J; Riley, M; Hardaker, C; Isaac, G H; Berry, G; Ingham, E

    2002-01-01

    Although the wear of existing metal-on-metal (MOM) hip prostheses (1 mm3/10(6) cycles) is much lower than the more widely used polyethylene-on-metal bearings, there are concerns about the toxicity of metal wear particles and elevated metal ion levels, both locally and systemically, in the human body. The aim of this study was to investigate the possibility of reducing the volume of wear, the concentration of metal debris and the level of metal ion release through using surface-engineered femoral heads. Three thick (8-12 microm) coatings (TiN, CrN and CrCN) and one thin (2 microm) coating (diamond-like carbon, DLC), were evaluated on the femoral heads when articulating against high carbon content cobalt-chromium alloy acetabular inserts (HC CoCrMo) and compared with a clinically used MOM cobalt-chromium alloy bearing couple using a physiological anatomical hip joint simulator (Leeds Mark II). This study showed that CrN, CrCN and DLC coatings produced substantially lower wear volumes for both the coated femoral heads and the HC CoCrMo inserts. The TiN coating itself had little wear, but it caused relatively high wear of the HC CoCrMo inserts compared with the other coatings. The majority of the wear debris for all half-coated couples comprised small, 30 nm or less, CoCrMo metal particles. The Co, Cr and Mo ion concentrations released from the bearing couples of CrN-, CrCN- and DLC-coated heads articulating against HC CoCrMo inserts were at least 7 times lower than those released from the clinical MOM prostheses. These surface-engineered femoral heads articulating on HC CoCrMo acetabular inserts produced significantly lower wear volumes and rates, and hence lower volumetric concentrations of wear particles, compared with the clinical MOM prosthesis. The substantially lower ion concentration released by these surface-engineered components provides important evidence to support the clinical application of this technology.

  5. A new interface element with progressive damage and osseointegration for modeling of interfaces in hip resurfacing.

    PubMed

    Caouette, Christiane; Bureau, Martin N; Lavigne, Martin; Vendittoli, Pascal-André; Nuño, Natalia

    2013-03-01

    Finite element models of orthopedic implants such as hip resurfacing femoral components usually rely on contact elements to model the load-bearing interfaces that connect bone, cement and implant. However, contact elements cannot simulate progressive degradation of bone-cement interfaces or osseointegration. A new interface element is developed to alleviate these shortcomings. This element is capable of simulating the nonlinear progression of bone-cement interface debonding or bone-implant interface osseointegration, based on mechanical stimuli in normal and tangential directions. The new element is applied to a hip resurfacing femoral component with a stem made of a novel biomimetic composite material. Three load cases are applied sequentially to simulate the 6-month period required for osseointegration of the stem. The effect of interdigitation depth of the bone-cement interface is found to be negligible, with only minor variations of micromotions. Numerical results show that the biomimetic stem progressively osseointegrates (alpha averages 0.7 on the stem surface, with spot-welds) and that bone-stem micromotions decrease below 10 microm. Osseointegration also changes the load path within the femoral bone: a decrease of 300 microepsilon was observed in the femoral head, and the inferomedial part of the femoral neck showed a slight increase of 165 microepsilon. There was also increased stress in the implant stem (from 7 to 11 MPa after osseointegration), indicating that part of the load is supported through the stem. The use of the new osseointegratable interface element has shown the osseointegration potential of the biomimetic stem. Its ability to model partially osseointegrated interfaces based on the mechanical conditions at the interface means that the new element could be used to study load transfer and osseointegration patterns on other models of uncemented hip resurfacing femoral components.

  6. Accuracy of navigation in hip resurfacing with different surgeons and varying anatomy.

    PubMed

    Schleicher, Iris; Haselbacher, Matthias; Mayr, Eckart; Kaiser, Peter M; Lenze, Florian W; Keiler, Alexander; Nogler, Michael

    2012-01-01

    The accuracy of a commercial imageless navigation system for hip resurfacing and its reproducibility among different surgeons and for varying femoral anatomy was tested by comparing conventional and navigated implantation of the femoral component on different sawbones in a hip simulator. The position of the component was measured on postoperative radiographs. Variance for varus/valgus alignment and anteversion was higher for conventional implantation. Among the three surgeons, operation time, chosen implant size and anteversion were significantly different for conventional implantation but not for the navigated method. Using navigation, no difference was found for normal and abnormal anatomy. Values obtained with the navigation system were consistent with those measured on radiographs. Navigation appeared to be accurate and helped to reduce outliers. This was true for the three different surgeons and in varying anatomical situations.

  7. Gait and stair function in total and resurfacing hip arthroplasty: a pilot study.

    PubMed

    Shrader, M Wade; Bhowmik-Stoker, Manoshi; Jacofsky, Marc C; Jacofsky, David J

    2009-06-01

    Standard total hip arthroplasty (THA) is the established surgical treatment for patients older than 65 years with progressive osteoarthritis but survivorship curves wane in patients younger than 50. Resurfacing hip arthroplasty (RHA) is an alternative for younger, active patients reportedly providing superior range of motion. Quantitative investigation of functional recovery following arthroplasty may elucidate limitations that aid in device selection. Although limited long-term kinematic data are available, the early rate of recovery and gait compensations are not well described. This information may aid in refining rehabilitation protocols based on limitations specific to the implant. We presumed hip motion and forces for subjects receiving RHA are more similar to age-matched controls during physically demanding tasks, such as stair negotiation, at early time points than those for THA. In a pilot study, we quantified walking and stair negotiation preoperatively and 3 months postoperatively for seven patients with RHA (mean age, 49 years), seven patients with standard THA (mean age, 52 years), and seven age-matched control subjects (mean age, 56 years). Although both treatment groups demonstrated trends toward functional recovery, the RHA group had greater improvements in hip extension and abduction moment indicating typical loading of the hip. Further investigation is needed to determine if differences persist long term or are clinically meaningful. PMID:19305961

  8. Impingement and stability of total hip arthroplasty versus femoral head resurfacing using a cadaveric robotics model.

    PubMed

    Colbrunn, R W; Bottros, J J; Butler, R S; Klika, A K; Bonner, T F; Greeson, C; van den Bogert, A J; Barsoum, W K

    2013-07-01

    We identified and compared the impingent-free range of motion (ROM) and subluxation potential for native hip, femoral head resurfacing (FHR), and total hip arthroplasty (THA). These constructs were also compared both with and without soft tissue to elucidate the role of the soft tissue. Five fresh-frozen bilateral hip specimens were mounted to a six-degree of freedom robotic manipulator. Under load-control parameters, in vivo mechanics were recreated to evaluate impingement free ROM, and the subluxation potential in two "at risk" positions for native hip, FHR, and THA. Impingement-free ROM of the skeletonized THA was greater than FHR for the anterior subluxation position. For skeletonized posterior subluxations, stability for THA and FHR constructs were similar, while a different pattern was observed for specimens with soft tissues intact. FHR constructs were more stable than THA constructs for both anterior and posterior subluxations. When the femoral neck is intact the joint has an earlier impingement profile placing the hip at risk for subluxation. However, FHR design was shown to be more stable than THA only when soft tissues were intact. PMID:23494830

  9. Ultrasound screening of periarticular soft tissue abnormality around metal-on-metal bearings.

    PubMed

    Nishii, Takashi; Sakai, Takashi; Takao, Masaki; Yoshikawa, Hideki; Sugano, Nobuhiko

    2012-06-01

    Although metal hypersensitivity or pseudotumors are concerns for metal-on-metal (MoM) bearings, detailed pathologies of patterns, severity, and incidence of periprosthetic soft tissue lesions are incompletely understood. We examined the potential of ultrasound for screening of periarticular soft tissue lesions around MoM bearings. Ultrasound examinations were conducted in 88 hips (79 patients) with MoM hip resurfacings or MoM total hip arthroplasties with a large femoral head. Four qualitative ultrasound patterns were shown, including normal pattern in 69 hips, joint-expansion pattern in 11 hips, cystic pattern in 5 hips, and mass pattern in 3 hips. Hips with the latter 3 abnormal patterns showed significantly higher frequency of clinical symptoms, without significant differences of sex, duration of implantation, head sizes, and cup abduction/anteversion angles, compared with hips with normal pattern. Ultrasound examination provides sensitive screening of soft tissue reactions around MoM bearings and may be useful in monitoring progression and defining treatment for periarticular soft tissue abnormalities. PMID:22047978

  10. Comparison of Whole-Blood Metal Ion Levels Among Four Types of Large-Head, Metal-on-Metal Total Hip Arthroplasty Implants: A Concise Follow-up, at Five Years, of a Previous Report.

    PubMed

    Hutt, Jonathan; Lavigne, Martin; Lungu, Eugen; Belzile, Etienne; Morin, François; Vendittoli, Pascal-André

    2016-02-17

    Few studies of total hip arthroplasty (THA) implants with a large-diameter femoral head and metal-on-metal design have directly compared the progression of metal ion levels over time and the relationship to complications. As we previously reported, 144 patients received one of four types of large-diameter-head, metal-on-metal THA designs (Durom, Birmingham, ASR XL, or Magnum implants). Cobalt, chromium, and titanium ion levels were measured over five years. We compared ion levels and clinical results over time. The Durom group showed the highest levels of cobalt (p ≤ 0.002) and titanium ions (p ≤ 0.03). Both the Durom and Birmingham groups demonstrated significant ongoing cobalt increases up to five years. Eight patients (seven with a Durom implant and one with a Birmingham implant) developed adverse local tissue reaction. Six Durom implants and one Birmingham implant required revision, with one pseudotumor under surveillance at the time of the most recent follow-up. We found that ion generation and related complications varied among designs. More concerning was that, for some designs, ion levels continued to increase. Coupling a cobalt-chromium adapter sleeve to an unmodified titanium femoral trunnion along with a large metal-on-metal bearing may explain the poor performances of two of the designs in the current study. PMID:26888673

  11. Return to sporting activity after Birmingham hip resurfacing arthroplasty: Mid term results

    PubMed Central

    Sandiford, Nemandra; Muirhead-Allwood, SK; Skinner, JA

    2015-01-01

    Background: Hip resurfacing arthroplasty (HRA) is primarily indicated for young, active patients with disabling coxarthrosis who wish to remain active and return to sports after surgery. Relatively few prospective studies have assessed return to sporting activity and impact of gender and age on this. Materials and Methods: Seventy-nine consecutive patients treated with HRA were included. Patients were reviewed clinically and radiologically. Function was assessed using the modified University of California Los Angeles (UCLA) activity score. The Oxford, Harris and WOMAC hip scores were calculated. Results: Average age at the time of surgery was 54.9 years (range 34.5–73.6 years). Average preoperative and postoperative UCLA scores were 4 and 7.6 respectively. Patients were involved in 2 (0–4) sporting activities preoperatively and 2 (0–5) postoperatively. Preoperative and postoperative Oxford Hip Scores, Harris Hip Score and WOMAC scores were 40, 46 and 51 and 16, 94 and 3 respectively (P < 0.0001). Patients returned to sports at an average of 3 months postoperatively. Conclusion: Patients were able to return to sports by 3 months and perform the same number of activities at preoperative intensity. Activity levels are maintained up to the medium term with few complications. PMID:26806965

  12. The thermal effects of lavage on 57 ox femoral heads prepared for hip resurfacing arthroplasty

    PubMed Central

    2013-01-01

    Background and purpose Previously, we have documented surface temperatures recorded by thermography great enough to cause osteonecrosis of the femoral head during hip resurfacing. We now performed an in vitro investigation with 3 questions: (1) whether water irrigation reduced bone surface temperature, (2) whether external bone temperatures were similar to core temperatures, and (3) whether blunting of the reamer affected temperature generation. Methods Using an ox-bone model, 57 femoral heads were peripherally reamed. The surface temperatures of bone were measured using a thermal camera and internal bone temperatures were measured using 2 theromocouples. We measured the effects of cooling with water at room temperature and with ice-cooled water. Progressive blunting of reamers was assessed over the 57 experiments. Results Mean and maximum temperatures generated during peripheral reaming were greater when no irrigation was used. Ice-cold saline protected femoral heads from thermal damage. External bone temperatures were much greater than internal temperatures, which were not sufficiently elevated to cause osteonecrosis regardless of lavage. Blunting of the reamer was not found to have a statistically significant effect in this study. Interpretation Cooling with ice-cooled water is recommended. Internal bone temperatures are not elevated despite the high surface temperatures reached during femoral head resurfacing. PMID:24079554

  13. The immunobiology of cobalt: demonstration of a potential aetiology for inflammatory pseudotumours after metal-on-metal replacement of the hip.

    PubMed

    Lawrence, H; Deehan, D; Holland, J; Kirby, J; Tyson-Capper, A

    2014-09-01

    Abnormal wear of cobalt-containing metal-on-metal joints is associated with inflammatory pseudotumours. Cobalt ions activate human toll-like receptor 4 (TLR4), which normally responds to bacterial lipopolysaccharide (LPS) in sepsis. Activation of TLR4 by LPS increases the expression of chemokines IL-8 and CXCL10, which recruit leukocytes and activated T-cells, respectively. This study was designed to determine whether cobalt induces a similar inflammatory response to LPS by promoting the expression of IL-8 and CXCL10. A human monocytic cell line, derived from acute monocytic leukaemia, was treated with cobalt ions and expression of IL-8 and CXCL10 measured at mRNA and protein levels. Cobalt-treated macrophages showed a 60-fold increase in IL-8 mRNA, and an eightfold increase in production of the mature chemokine (both p < 0.001); expression of the CXCL10 gene and protein was also significantly increased by cobalt (both p < 0.001). Experiments were also performed in the presence of CLI-095, a TLR4-specific antagonist which abrogated the cobalt-mediated increase in IL-8 and CXCL10 expression. These findings suggest that cobalt ions induce inflammation similar to that observed during sepsis by the simultaneous activation of two TLR4-mediated signalling pathways. These pathways result in increased production of IL-8 and CXCL10, and may be implicated in pseudotumour formation following metal-on-metal replacement.

  14. A Two Centre Study to Assess the Long-term Performance of the Pinnacle™ Cup With a Metal-on-Metal Bearing in Primary Total Hip Replacement

    ClinicalTrials.gov

    2016-10-06

    Rheumatoid Arthritis; Osteoarthritis; Post-traumatic Arthritis; Collagen Disorders; Avascular Necrosis; Traumatic Femoral Fractures; Nonunion of Femoral Fractures; Congenital Hip Dysplasia; Slipped Capital Femoral Epiphysis

  15. Toxicology of wear particles of cobalt-chromium alloy metal-on-metal hip implants Part II: Importance of physicochemical properties and dose in animal and in vitro studies as a basis for risk assessment.

    PubMed

    Madl, Amy K; Kovochich, Michael; Liong, Monty; Finley, Brent L; Paustenbach, Dennis J; Oberdörster, Günter

    2015-07-01

    The objective of the Part II analysis was to evaluate animal and in vitro toxicology studies of CoCr particles with respect to their physicochemistry and dose relevance to metal-on-metal (MoM) implant patients as derived from Part I. In the various toxicology studies, physicochemical characteristics were infrequently considered and administered doses were orders of magnitude higher than what occurs in patients. Co was consistently shown to rapidly release from CoCr particles for distribution and elimination from the body. CoCr micron sized particles appear more biopersistent in vivo resulting in inflammatory responses that are not seen with similar mass concentrations of nanoparticles. We conclude, that in an attempt to obtain data for a complete risk assessment, future studies need to focus on physicochemical characteristics of nano and micron sized particles and on doses and dose metrics relevant to those generated in patients or in properly conducted hip simulator studies.

  16. Center of Mass Compensation during Gait in Hip Arthroplasty Patients: Comparison between Large Diameter Head Total Hip Arthroplasty and Hip Resurfacing.

    PubMed

    Bouffard, Vicky; Nantel, Julie; Therrien, Marc; Vendittoli, Pascal-André; Lavigne, Martin; Prince, François

    2011-01-01

    Objective. To compare center of mass (COM) compensation in the frontal and sagittal plane during gait in patients with large diameter head total hip arthroplasty (LDH-THA) and hip resurfacing (HR). Design. Observational study. Setting. Outpatient biomechanical laboratory. Participants. Two groups of 12 patients with LDH-THA and HR recruited from a larger randomized study and 11 healthy controls. Interventions. Not applicable. Main Outcome Measures. To compare the distance between the hip prosthetic joint center (HPJC) and the COM. The ratio (R(HPJC-COM)) and the variability (CV(HPJC-COM)) were compared between groups. Hip flexor, abductor, and adductor muscle strength was also correlated between groups while radiographic measurements were correlated with the outcome measures. Results. In the frontal plane, HR shows less variability than healthy controls at push-off and toe-off and R(HPJC-COM) is correlated with the muscle strength ratios (FR(ABD)) at heel contact, maximal weight acceptance, and mid stance. In the sagittal plane, LDH-THA has a higher R(HPJC-COM) than healthy controls at push-off, and CV(HPJC-COM) is significantly correlated with FR(FLEX). Conclusions. One year after surgery, both groups of patients, LDH-THA and HR, demonstrate minor compensations at some specific instant of the gait cycle, in both frontal and sagittal planes. However, their locomotion pattern is similar to the healthy controls. PMID:22110976

  17. Validation of primary metal-on-metal hip arthroplasties on the National Joint Registry for England, Wales and Northern Ireland using data from the London Implant Retrieval Centre: a study using the NJR dataset.

    PubMed

    Sabah, S A; Henckel, J; Cook, E; Whittaker, R; Hothi, H; Pappas, Y; Blunn, G; Skinner, J A; Hart, A J

    2015-01-01

    Arthroplasty registries are important for the surveillance of joint replacements and the evaluation of outcome. Independent validation of registry data ensures high quality. The ability for orthopaedic implant retrieval centres to validate registry data is not known. We analysed data from the National Joint Registry for England, Wales and Northern Ireland (NJR) for primary metal-on-metal hip arthroplasties performed between 2003 and 2013. Records were linked to the London Implant Retrieval Centre (RC) for validation. A total of 67,045 procedures on the NJR and 782 revised pairs of components from the RC were included. We were able to link 476 procedures (60.9%) recorded with the RC to the NJR successfully. However, 306 procedures (39.1%) could not be linked. The outcome recorded by the NJR (as either revised, unrevised or death) for a primary procedure was incorrect in 79 linked cases (16.6%). The rate of registry-retrieval linkage and correct assignment of outcome code improved over time. The rates of error for component reference numbers on the NJR were as follows: femoral head category number 14/229 (5.0%); femoral head batch number 13/232 (5.3%); acetabular component category number 2/293 (0.7%) and acetabular component batch number 24/347 (6.5%). Registry-retrieval linkage provided a novel means for the validation of data, particularly for component fields. This study suggests that NJR reports may underestimate rates of revision for many types of metal-on-metal hip replacement. This is topical given the increasing scope for NJR data. We recommend a system for continuous independent evaluation of the quality and validity of NJR data.

  18. Metal ion levels and lymphocyte counts: ASR hip resurfacing prosthesis vs. standard THA

    PubMed Central

    2013-01-01

    Background and purpose Wear particles from metal–on–metal arthroplasties are under suspicion for adverse effects both locally and systemically, and the DePuy ASR Hip Resurfacing System (RHA) has above–average failure rates. We compared lymphocyte counts in RHA and total hip arthroplasty (THA) and investigated whether cobalt and chromium ions affected the lymphocyte counts. Method In a randomized controlled trial, we followed 19 RHA patients and 19 THA patients. Lymphocyte subsets and chromium and cobalt ion concentrations were measured at baseline, at 8 weeks, at 6 months, and at 1 and 2 years. Results The T–lymphocyte counts for both implant types declined over the 2–year period. This decline was statistically significant for CD3+CD8+ in the THA group, with a regression coefficient of –0.04 × 109cells/year (95% CI: –0.08 to –0.01). Regression analysis indicated a depressive effect of cobalt ions in particular on T–cells with 2–year whole–blood cobalt regression coefficients for CD3+ of –0.10 (95% CI: –0.16 to –0.04) × 109 cells/parts per billion (ppb), for CD3+CD4+ of –0.06 (–0.09 to –0.03) × 109 cells/ppb, and for CD3+CD8+ of –0.02 (–0.03 to –0.00) × 109 cells/ppb. Interpretation Circulating T–lymphocyte levels may decline after surgery, regardless of implant type. Metal ions—particularly cobalt—may have a general depressive effect on T– and B–lymphocyte levels. Registered with ClinicalTrials.gov under # NCT01113762 PMID:23597114

  19. Retrospective cohort study of the performance of the Pinnacle metal on metal (MoM) total hip replacement: a single-centre investigation in combination with the findings of a national retrieval centre

    PubMed Central

    Langton, David John; Sidaginamale, Raghavendra Prasad; Avery, Peter; Waller, Sue; Tank, Ghanshyabhai; Lord, James; Joyce, Thomas; Cooke, Nick; Logishetty, Raj; Nargol, Antoni Viraf Francis

    2016-01-01

    Objectives To determine risk factors for revision in patients implanted with a commonly used metal on metal (MoM) hip replacement. Design Retrospective cohort study in combination with a prospective national retrieval study (Northern Retrieval Registry (NRR)). Setting Combined orthopaedic unit in combination with the NRR. Participants All patients implanted with a DePuy Pinnacle MoM hip prostheses by the 2 senior authors were invited to attend for a review which included clinical examination, blood metal ion measurements, radiographs and targeted imaging. Explanted components underwent wear analysis using validated methodology and these results were compared with those obtained from the NRR. Results 489 MoM Pinnacle hips were implanted into 434 patients (243 females and 191 males). Of these, 352 patients attended the MoM recall clinics. 64 patients had died during the study period. For the purposes of survival analysis, non-attendees were assumed to have well-functioning prostheses. The mean follow-up of the cohort as a whole was 89 months. 71 hips were revised. Prosthetic survival for the whole cohort was 83.6% (79.9–87.3) at 9 years. The majority of explanted devices exhibited signs of taper junction failure. Risk factors for revision were bilateral MoM prostheses, smaller Pinnacle liners, and implantation in 2006 and later years. A significant number of devices were found to be manufactured out of their specifications. This was confirmed with analysis of the wider data set from the NRR. Conclusions This device was found to have an unacceptably high revision rate. Bilateral prostheses, those implanted into female patients and devices implanted in later years were found to be at greater risk. A significant number of explanted components were found to be manufactured with bearing diameters outside of the manufacturer's stated tolerances. Our findings highlight the clinical importance of hitherto unrecognised variations in device production. PMID:27130159

  20. Shorter, rough trunnion surfaces are associated with higher taper wear rates than longer, smooth trunnion surfaces in a contemporary large head metal-on-metal total hip arthroplasty system.

    PubMed

    Brock, Timothy M; Sidaginamale, Raghavendra; Rushton, Steven; Nargol, Antoni V F; Bowsher, John G; Savisaar, Christina; Joyce, Tom J; Deehan, David J; Lord, James K; Langton, David J

    2015-12-01

    Taper wear at the head-neck junction is a possible cause of early failure in large head metal-on-metal (LH-MoM) hip replacements. We hypothesized that: (i) taper wear may be more pronounced in certain product designs; and (ii) an increased abductor moment arm may be protective. The tapers of 104 explanted LH-MoM hip replacements revised for adverse reaction to metal debris (ARMD) from a single manufacturer were analyzed for linear and volumetric wear using a co-ordinate measuring machine. The mated stem was a shorter 12/14, threaded trunnion (n=72) or a longer, smooth 11/13 trunnion (n=32). The abductor moment arm was calculated from pre-revision radiographs. Independent predictors of linear and volumetric wear included taper angle, stem type, and the horizontal moment arm. Tapers mated with the threaded 12/14 trunnion had significantly higher rates of volumetric wear (0.402 mm3/yr vs. 0.123 mm3/yr [t=-2.145, p=0.035]). There was a trend to larger abductor moment arms being protective (p=0.055). Design variation appears to play an important role in taper-trunnion junction failure. We recommend that surgeons bear these findings in mind when considering the use of a short, threaded trunnion with a cobalt-chromium head. PMID:26135357

  1. Shorter, rough trunnion surfaces are associated with higher taper wear rates than longer, smooth trunnion surfaces in a contemporary large head metal-on-metal total hip arthroplasty system.

    PubMed

    Brock, Timothy M; Sidaginamale, Raghavendra; Rushton, Steven; Nargol, Antoni V F; Bowsher, John G; Savisaar, Christina; Joyce, Tom J; Deehan, David J; Lord, James K; Langton, David J

    2015-12-01

    Taper wear at the head-neck junction is a possible cause of early failure in large head metal-on-metal (LH-MoM) hip replacements. We hypothesized that: (i) taper wear may be more pronounced in certain product designs; and (ii) an increased abductor moment arm may be protective. The tapers of 104 explanted LH-MoM hip replacements revised for adverse reaction to metal debris (ARMD) from a single manufacturer were analyzed for linear and volumetric wear using a co-ordinate measuring machine. The mated stem was a shorter 12/14, threaded trunnion (n=72) or a longer, smooth 11/13 trunnion (n=32). The abductor moment arm was calculated from pre-revision radiographs. Independent predictors of linear and volumetric wear included taper angle, stem type, and the horizontal moment arm. Tapers mated with the threaded 12/14 trunnion had significantly higher rates of volumetric wear (0.402 mm3/yr vs. 0.123 mm3/yr [t=-2.145, p=0.035]). There was a trend to larger abductor moment arms being protective (p=0.055). Design variation appears to play an important role in taper-trunnion junction failure. We recommend that surgeons bear these findings in mind when considering the use of a short, threaded trunnion with a cobalt-chromium head.

  2. Birmingham Hip Resurfacing: A Single Surgeon Series Reported at a Minimum of 10 Years Follow-Up.

    PubMed

    Mehra, Akshay; Berryman, Fiona; Matharu, Gulraj S; Pynsent, Paul B; Isbister, Eric S

    2015-07-01

    We report outcomes on 120 Birmingham Hip Resurfacings (BHRs) (mean age 50 years) at a minimum of ten-years follow-up. Cases were performed by one surgeon and included his learning curve. Six hips were revised, with no revisions for infection, dislocation, or adverse reaction to metal debris. Ten-year survival was 94.2% (95% confidence interval (CI) 88.8%-98.7%) for all revisions and 96.1% (95% CI 91.5%-99.8%) for revisions for aseptic loosening. Gender (P = 0.463) and head size (P = 0.114) did not affect revision risk. Mean post-operative Harris hip score was 84.0. Contrary to previous independent reports, good outcomes into the second decade were achieved with the BHR in both men and women. Longer term follow-up will confirm whether these promising outcomes in women continue.

  3. Influence of different DXA acquisition modes on monitoring the changes in bone mineral density after hip resurfacing arthroplasty.

    PubMed

    Hakulinen, Mikko A; Borg, Håkan; Häkkinen, Arja; Parviainen, Tapani; Kiviranta, Ilkka; Jurvelin, Jukka S

    2012-01-01

    Dual-energy X-ray absorptiometry (DXA) is a technique enabling the measurement of bone mineral density (BMD) around prostheses after hip resurfacing arthroplasty (HRA). In this study, we evaluated the consistency of different DXA acquisition modes with 33 patients who had undergone HRA. Patients were scanned with DXA immediately after surgery and at 3-, 6-, and 12-mo time points. All the patients were scanned with dual femur and orthopedic hip acquisition modes and analyzed using 10-region ROI model. With both acquisition modes, a statistically significant decrease (p<0.05, Wilcoxon's test) in BMD at 3mo was revealed in 3 ROIs, located to upper and lateral upper femur. Both acquisition modes detected similarly (p<0.01) preservation of the femoral bone stock within 12mo in all but 1 ROI. The applied acquisition protocols involved the use of different footplates for hip fixation. Because the differences between acquisition modes ranged between +1.6% and -7.1% and the reproducibility of BMD values can vary by as much as 28% due to hip rotation, it is proposed that both dual femur and orthopedic hip acquisition modes can be used to monitor the changes in BMD after HRA. However, the same hip rotation is recommended for all DXA measurements.

  4. Adverse local tissue reaction (ALTR) associated with corrosion products in metal-on-metal and dual modular neck total hip replacements is associated with upregulation of interferon gamma-mediated chemokine signaling.

    PubMed

    Kolatat, Kritti; Perino, Giorgio; Wilner, Gabrielle; Kaplowitz, Elianna; Ricciardi, Benjamin F; Boettner, Friedrich; Westrich, Geoffrey H; Jerabek, Seth A; Goldring, Steven R; Purdue, P Edward

    2015-10-01

    Adverse local tissue reactions (ALTR) associated with tribocorrosion following total hip arthroplasty (THA) have become a significant clinical concern in recent years. In particular, implants featuring metal-on-metal bearing surfaces and modular femoral stems have been reported to result in elevated rates of ALTR. These tribocorrosion-related tissue reactions are characterized by marked necrosis and lymphocytic infiltration, which contrasts sharply with the macrophagic and foreign body giant cell inflammation associated with polyethylene wear particle induced peri-implant osteolysis. In this study, we characterize tribocorrosion-associated ALTR at a molecular level. Gene expression profiling of peri-implant tissue around failing implants identifies upregulation of numerous inflammatory mediators in ALTR, including several interferon gamma inducible factors, most notably the chemokines MIG/CXCL9 and IP-10/CXCL10. This expression profile is distinct from that associated with polyethylene wear induced osteolysis, which is characterized by induction of markers of alternative macrophage activation, such as chitotriosidase (CHIT-1). Importantly, MIG/CXCL9 and IP-10/CXCL10 are also elevated at the protein level in the synovial fluid and, albeit more moderately, the serum, of ALTR patients, raising the possibility that these factors may serve as circulating biomarkers for the early detection of ALTR in at-risk patients. PMID:25940887

  5. Pseudotumour incidence, cobalt levels and clinical outcome after large head metal-on-metal and conventional metal-on-polyethylene total hip arthroplasty: mid-term results of a randomised controlled trial.

    PubMed

    van der Veen, H C; Reininga, I H F; Zijlstra, W P; Boomsma, M F; Bulstra, S K; van Raay, J J A M

    2015-11-01

    We compared the incidence of pseudotumours after large head metal-on-metal (MoM) total hip arthroplasty (THA) with that after conventional metal-on-polyethylene (MoP) THA and assessed the predisposing factors to pseudotumour formation. From a previous randomised controlled trial which compared large head (38 mm to 60 mm) cementless MoM THA with conventional head (28 mm) cementless MoP THA, 93 patients (96 THAs: 41 MoM (21 males, 20 females, mean age of 64 years, standard deviation (sd) 4) and 55 MoP (25 males, 30 females, mean age of 65 years, sd 5) were recruited after a mean follow-up of 50 months (36 to 64). The incidence of pseudotumours, measured using a standardised CT protocol was 22 (53.7%) after MoM THA and 12 (21.8%) after MoP THA. Women with a MoM THA were more likely to develop a pseudotumour than those with a MoP THA (15 vs 7, odds ratio (OR) = 13.4, p < 0.001). There was a similar incidence of pseudotumours in men with MoM THAs and those with MoP THAs (7 vs 5, OR = 2.1, p = 0.30). Elevated cobalt levels (≥ 5 microgram/L) were only associated with pseudotumours in women with a MoM THA. There was no difference in mean Oxford and Harris hip scores between patients with a pseudotumour and those without. Contrary to popular belief, pseudotumours occur frequently around MoP THAs. Women with a MoM THA and an elevated cobalt level are at greatest risk. In this study, pseudotumours had no effect on the functional outcome after either large head MoM or conventional MoP THA.

  6. Comparison of Patient-Reported Outcome from Neck-Preserving, Short-Stem Arthroplasty and Resurfacing Arthroplasty in Younger Osteoarthritis Patients

    PubMed Central

    Dettmer, Marius; Pourmoghaddam, Amir; Kreuzer, Stefan W.

    2015-01-01

    Hip resurfacing has been considered a good treatment option for younger, active osteoarthritis patients. However, there are several identified issues concerning risk for neck fractures and issues related to current metal-on-metal implant designs. Neck-preserving short-stem implants have been discussed as a potential alternative, but it is yet unclear which method is better suited for younger adults. We compared hip disability and osteoarthritis outcome scores (HOOS) from a young group of patients (n = 52, age 48.9 ± 6.1 years) who had received hip resurfacing (HR) with a cohort of patients (n = 73, age 48.2 ± 6.6 years) who had received neck-preserving, short-stem implant total hip arthroplasty (THA). Additionally, durations for both types of surgery were compared. HOOS improved significantly preoperatively to last followup (>1 year) in both groups (p < 0.0001, η2 = 0.69); there were no group effects or interactions. Surgery duration was significantly longer for resurfacing (104.4 min ± 17.8) than MiniHip surgery (62.5 min ± 14.8), U = 85.0, p < 0.0001, η2 = 0.56. The neck-preserving short-stem approach may be preferable to resurfacing due to the less challenging surgery, similar outcome, and controversy regarding resurfacing implant designs. PMID:26101669

  7. Have cementless and resurfacing components improved the medium-term results of hip replacement for patients under 60 years of age?

    PubMed Central

    Mason, James; Baker, Paul; Gregg, Paul J; Porter, Martyn; Deehan, David J; Reed, Mike R

    2015-01-01

    Background and purpose The optimal hip replacement for young patients remains unknown. We compared patient-reported outcome measures (PROMs), revision risk, and implant costs over a range of hip replacements. Methods We included hip replacements for osteoarthritis in patients under 60 years of age performed between 2003 and 2010 using the commonest brand of cemented, cementless, hybrid, or resurfacing prosthesis (11,622 women and 13,087 men). The reference implant comprised a cemented stem with a conventional polyethylene cemented cup and a standard-sized head (28- or 32-mm). Differences in implant survival were assessed using competing-risks models, adjusted for known prognostic influences. Analysis of covariance was used to assess improvement in PROMs (Oxford hip score (OHS) and EQ5D index) in 2014 linked procedures. Results In males, PROMs and implant survival were similar across all types of implants. In females, revision was statistically significantly higher in hard-bearing and/or small-stem cementless implants (hazard ratio (HR) = 4) and resurfacings (small head sizes (< 48 mm): HR = 6; large head sizes (≥ 48 mm): HR = 5) when compared to the reference cemented implant. In component combinations with equivalent survival, women reported significantly greater improvements in OHS with hybrid implants (22, p = 0.006) and cementless implants (21, p = 0.03) (reference, 18), but similar EQ5D index. For men and women, National Health Service (NHS) costs were lowest with the reference implant and highest with a hard-bearing cementless replacement. Interpretation In young women, hybrids offer a balance of good early functional improvement and low revision risk. Fully cementless and resurfacing components are more costly and do not provide any additional benefit for younger patients. PMID:25285617

  8. Bone mineral density of the proximal femur after hip resurfacing arthroplasty: 1-year follow-up study

    PubMed Central

    2011-01-01

    Background Hip resurfacing arthroplasty (HRA) is considered a bone-preserving procedure and may eliminate proximal femoral stress shielding and osteolysis. However, in addition to implant-related stress-shielding factors, various patient-related factors may also have an effect on bone mineral density (BMD) of the proximal femur in patients with HRA. Thus, we studied the effects of stem-neck angle, demographic variables, and physical functioning on the BMD of the proximal femur in a one-year follow-up. Methods Thirty three patients (9 females and 24 males) with a mean (SD) age of 55 (9) years were included in the study. BMD was measured two days and 3, 6, and 12 months postoperatively and 10 regions of interest (ROI) were used. Stem-neck angle was analyzed from anteroposterior radiographs. Results Three months postoperatively, BMD decreased in six out of 10 regions of interest (ROI) on the side operated on and in one ROI on the control side (p < 0.05) compared to the second postoperative day. At 12 months, BMD had increased in 7 ROIs on the operated side and one ROI on the control side (all p < 0.001). Correlation was found between the stem-neck angle and BMD in ROIs 2, 3, 7, and 9 (r = 0.36 - 0.61). In multiple regression analysis, stem-neck angle, age, sex, body mass index, and walking distance did not explain the BMD changes. Conclusions After an early drop, the BMD of the upper femur was restored and even exceeded the preoperative level at one year follow-up. From a clinical standpoint, the changes in BMD in these HRA patients could not be explained by stem-neck angle or patient related factors. PMID:21595913

  9. Metal-on-metal joint bearings and hematopoetic malignancy

    PubMed Central

    2012-01-01

    Abstract This is a review of the hip arthroplasty era. We concentrate on new metal bearings, surface replacements, and the lessons not learned, and we highlight recent reports on malignancies and joint implants. A low incidence of blood malignancies has been found in bone marrow taken at prosthetic surgery. The incidence is increased after replacement with knee implants that release very low systemic levels of metal ions. A carcinogenic effect of the high levels of metal ions released by large metal-on-metal implants cannot be excluded. Ongoing Swedish implant registry studies going back to 1975 can serve as a basis for evaluation of this risk. PMID:23140092

  10. Blood metal ion testing is an effective screening tool to identify poorly performing metal-on-metal bearing surfaces

    PubMed Central

    Sidaginamale, R. P.; Joyce, T. J.; Lord, J. K.; Jefferson, R.; Blain, P. G.; Nargol, A. V. F.; Langton, D. J.

    2013-01-01

    Objectives The aims of this piece of work were to: 1) record the background concentrations of blood chromium (Cr) and cobalt (Co) concentrations in a large group of subjects; 2) to compare blood/serum Cr and Co concentrations with retrieved metal-on-metal (MoM) hip resurfacings; 3) to examine the distribution of Co and Cr in the serum and whole blood of patients with MoM hip arthroplasties; and 4) to further understand the partitioning of metal ions between the serum and whole blood fractions. Methods A total of 3042 blood samples donated to the local transfusion centre were analysed to record Co and Cr concentrations. Also, 91 hip resurfacing devices from patients who had given pre-revision blood/serum samples for metal ion analysis underwent volumetric wear assessment using a coordinate measuring machine. Linear regression analysis was carried out and receiver operating characteristic curves were constructed to assess the reliability of metal ions to identify abnormally wearing implants. The relationship between serum and whole blood concentrations of Cr and Co in 1048 patients was analysed using Bland-Altman charts. This relationship was further investigated in an in vitro study during which human blood was spiked with trivalent and hexavalent Cr, the serum then separated and the fractions analysed. Results Only one patient in the transfusion group was found to have a blood Co > 2 µg/l. Blood/Serum Cr and Co concentrations were reliable indicators of abnormal wear. Blood Co appeared to be the most useful clinical test, with a concentration of 4.5 µg/l showing sensitivity and specificity for the detection of abnormal wear of 94% and 95%, respectively. Generated metal ions tended to fill the serum compartment preferentially in vivo and this was replicated in the in vitro study when blood was spiked with trivalent Cr and bivalent Co. Conclusions Blood/serum metal ion concentrations are reliable indicators of abnormal wear processes. Important differences exist

  11. Taper junction failure in large-diameter metal-on-metal bearings

    PubMed Central

    Langton, D. J.; Sidaginamale, R.; Lord, J. K.; Nargol, A. V. F.; Joyce, T. J.

    2012-01-01

    Objectives An ongoing prospective study to investigate failing metal-on-metal hip prostheses was commenced at our centre in 2008. We report on the results of the analysis of the first consecutive 126 failed mated total hip prostheses from a single manufacturer. Methods Analysis was carried out using highly accurate coordinate measuring to calculate volumetric and linear rates of the articular bearing surfaces and also the surfaces of the taper junctions. The relationship between taper wear rates and a number of variables, including bearing diameter and orientation of the acetabular component, was investigated. Results The measured rates of wear and distribution of material loss from the taper surfaces appeared to show that the primary factor leading to taper failure is the increased lever arm acting on this junction in contemporary large-diameter metal-on-metal hip replacements. Conclusions Our analysis suggests that varus stems, laterally engaging taper systems and larger head diameters all contribute to taper failure. PMID:23610672

  12. Preliminary Results of Implantation in Animal Model and Osteoblast Culture Evaluation of Prototypes of Biomimetic Multispiked Connecting Scaffold for Noncemented Stemless Resurfacing Hip Arthroplasty Endoprostheses

    PubMed Central

    Uklejewski, Ryszard; Rogala, Piotr; Winiecki, Mariusz; Kędzia, Andrzej; Ruszkowski, Piotr

    2013-01-01

    We present the new fixation method for RHA (resurfacing hip arthroplasty) endoprostheses by means of the biomimetic multispiked connecting scaffold (MSC-Scaffold). Such connecting scaffold can generate new type of RHA endoprostheses, that is stemless and fixed entirely without cement. The preprototypes of this MSC-Scaffold were manufactured with modern additive laser additive technology (SLM). The pilot surgical implantations in animal model (two laboratory swine) of MSC-Scaffold preprototypes have showed after two months neither implant loosening, migration, and nor other early complications. From the results of performed histopathological evaluation of the periscaffold spikes bone tissue and 10-day culture of human osteoblasts (NHOst) we can conclude that (1) the scaffolding effect was obtained and (2) to improve the osseointegration of the scaffold spikes, their material surface should be physicochemically modified (e.g., with hydroxyapatite). Some histopathological findings in the periscaffold domain near the MSC-Scaffold spikes bases (fibrous connective tissue and metallic particles near the MSC-Scaffold spikes bases edges) prompt considering the necessity to optimize the design of the MSC-Scaffold in the regions of its interspike space near the spikes bases edges, to provide more room for new bone formation in this region and for indispensable post-processing (glass pearl blasting) after the SLM manufacturing. PMID:23984397

  13. Metal-on-metal: history, state of the art (2010)

    PubMed Central

    2011-01-01

    The history of metal-on-metal bearing began with K. Mc Kee. Several "episodes" have marked the history of metal-on-metal articulations, and each has contributed to a better understanding of this type of tribology. But to date the indications for this bearing are debated and are subject to reservations because of the existence of permanently elevated levels of circulating metal ions. It therefore appears that the monitoring of our patients, the documentation of our revisions and the collaboration with our industry partners as well as communicating with our biology and pathology colleagues is necessary to help us solve these problems. PMID:21234564

  14. Patients with metal-on-metal articulation in trapeziometacarpal total joint arthroplasty may have elevated serum chrome and cobalt.

    PubMed

    Hansen, T B; Dremstrup, L; Stilling, M

    2013-10-01

    Serum chrome and cobalt was measured in 50 patients with trapeziometacarpal total joint replacement with metal-on-metal articulation and compared with serum chrome and cobalt values in 23 patients with trapeziometacarpal total joint replacement with metal-on-polyethylene articulation. In 10 of 50 (20%) patients with metal-on-metal articulation, slightly elevated serum chrome or cobalt values were found compared with only one in 23 (4%) patients with metal-on-polyethylene articulation. All metal values were lower than accepted 'normal values' for metal-on-metal hip arthroplasty and so considered not to be a general health risk. However, the mean disabilities of the arm, shoulder and hand (DASH) score was 24 in patients with elevated serum chrome or cobalt compared with 10 in patients with normal metal values (p < 0.05) suggesting a local clinical effect of the elevated serum chrome or cobalt values. We recommend that patients with trapeziometacarpal total joint replacement with metal-on-metal articulation are followed with DASH score and radiological examination every 3-5 years and serum chrome and cobalt should be analysed in symptomatic cases to learn more about possible local complications leading to, or arising from, metal debris.

  15. Scar revision via resurfacing.

    PubMed

    Bradley, D T; Park, S S

    2001-11-01

    Numerous techniques exist to treat noticeable facial scars. Techniques range from surgical excision to resurfacing. In this review of dermabrasion and laser resurfacing, we address the clinical considerations, techniques, adjuncts, and peri-operative management of scar resurfacing. Dermabrasion offers the advantage of being a tried-and-true technique familiar to surgeons. Recent advances in laser technology have resulted in the increased use of pulsed-dye lasers (PDLs), erbium:yttrium-aluminum-garnet (YAG) lasers, and CO(2) lasers. PDLs are effective for hypertrophic scars and show lower rates of recurrence compared with erbium:YAG and CO2 lasers. In contrast, erbium:YAG and CO(2) lasers are well suited to treating atrophic and acne scars. Chemical peels play a minor role in scar resurfacing and function primarily as an adjunct. Scar resurfacing is an integral part of scar camouflage and is often used in conjunction with excision and irregularization techniques.

  16. Evaluation of the wear properties of a metal-on-metal total joint replacement system and in vitro macrophage response to resultant wear particles

    NASA Astrophysics Data System (ADS)

    St. John, Kenneth Raymond

    The wear of the polyethylene in total joint prostheses has been a source of morbidity and early device failure which has been extensively reported in the last ten to twelve years. While research continues to attempt to reduce the wear of polyethylene joint bearing surfaces by modifications in polymer processing, there is a renewed interest in the use of metal-on-metal bearing couples for hip replacement devices. This study investigated the in vitro wear resistance of two cobalt/chromium/molybdenum alloys, which differed primarily in the carbon content, as potential alloys for use in such a metal-on-metal hip bearing couple. The results showed that the alloy with the higher (0.25%) carbon content was more wear resistant and this alloy was chosen for testing in a hip simulator system which modeled the loads and motions which might be exerted on a clinically implanted hip replacement. Comparison of the results of metal-on-polyethylene specimens to metal-on-metal specimens showed that the volumetric wear of the metal-on-polyethylene bearing couple over 5,000,000 cycles was 110--180 times as great as that for the metal bearing couple. Polyethylene and metal particles retrieved from either pin-on-disk testing lubricant or hip simulator testing lubricant were cleaned and examined for consistency with the particles reported by other laboratories for particles from periprosthetic tissues and found to be similar. The particles were then added to macrophage (J774a) cell cultures and the release of Prostaglandin E2, Interleukin-6, and Tumor Necrosis Factor alpha measured for each experiment in response to the particles. The cell mediators released by the cells was found to correlate with the dosage of particles and the chemical identity of the particles. Most of the cellular response to the polyethylene particles seemed to be as a result of phagocytosis of the particles while most of the response to metal particles seemed to be related to cytotoxicity of the particles. Based

  17. A HIERARCHY OF COMPUTATIONALLY DERIVED SURGICAL AND PATIENT INFLUENCES ON METAL ON METAL PRESS-FIT ACETABULAR CUP FAILURE

    PubMed Central

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

    2014-01-01

    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. PMID:22513086

  18. Case studies in management of THA failure secondary to taper corrosion, modular junctions and metal-on-metal bearings.

    PubMed

    Lombardi, Adolph V

    2014-04-01

    The diagnosis and treatment of patients with painful total hip arthroplasties secondary to taper corrosion and wear of modular junctions and metal-on-metal bearings represents a major challenge for the orthopaedic clinician. Guidelines are evolving as we analyze the growing body of evidence regarding metal-related failures of orthopaedic implants and adverse reactions to metal debris. In this article 6 case examples are presented to enhance understanding and application of current evidence into practice. Clinical expertise is integrated with the best available evidence from research and national joint registries data into the decision making process relevant for patient care in everyday practice. Issues addressed include understanding taper corrosion and metal failure mechanisms, clinical presentation of adverse soft tissue reactions, utility of specialized tests such as metal ion analysis and cross-sectional imaging studies, the utility of modular components for primary THA, dealing with recalled component, and current recommendations.

  19. New Insights into Hard Phases of CoCrMo Metal-on-Metal Hip Replacements

    PubMed Central

    Liao, Y.; Pourzal, R.; Stemmer, P.; Wimmer, M.A.; Jacobs, J.J.; Fischer, A.; Marks, L. D.

    2012-01-01

    The microstructural and mechanical properties of the hard phases in CoCrMo prosthetic alloys in both cast and wrought conditions were examined using transmission electron microscopy and nanoindentation. Besides the known carbides of M23C6-type (M=Cr, Mo, Co) and M6C-type which are formed by either eutectic solidification or precipitation, a new mixed-phase hard constituent has been found in the cast alloys, which is composed of ~100 nm fine grains. The nanosized grains were identified to be mostly of M23C6 type using nano-beam precession electron diffraction, and the chemical composition varied from grain to grain being either Cr- or Co-rich. In contrast, the carbides within the wrought alloy having the same M23C6 structure were homogeneous, which can be attributed to the repeated heating and deformation steps. Nanoindentation measurements showed that the hardness of the hard phase mixture in the cast specimen was ~15.7 GPa, while the M23C6 carbides in the wrought alloy were twice as hard (~30.7 GPa). The origin of the nanostructured hard phase mixture was found to be related to slow cooling during casting. Mixed hard phases were produced at a cooling rate of 0.2 °C/s, whereas single phase carbides were formed at a cooling rate of 50 °C/s. This is consistent with sluggish kinetics and rationalizes different and partly conflicting microstructural results in the literature, and could be a source of variations in the performance of prosthetic devices in-vivo. PMID:22659365

  20. Information for Patients Who Have Metal-on-Metal Hip Implants

    MedlinePlus

    ... their implants. These problems included: General hypersensitivity reaction (skin rash) Cardiomyopathy Neurological changes including sensory changes (auditory, or visual impairments) Psychological status change ( ...

  1. Simultaneous measurement of friction and wear in hip simulators.

    PubMed

    Haider, Hani; Weisenburger, Joel N; Garvin, Kevin L

    2016-05-01

    (statistically significant, p < 0.001), and the coating wore away on all coated hips eventually. Higher friction mostly correlated with higher wear or damage to femoral heads or implant coatings, except for the highly cross-linked wear resistant ultrahigh-molecular-weight polyethylene which had slightly higher friction, confirming the same finding in other independent studies. This type of friction measurements can help screen for clamping and elevated wear of metal-on-metal and resurfacing total hip replacements, surgical malpositioning, and abraded and otherwise damaged surfaces.

  2. Simultaneous measurement of friction and wear in hip simulators.

    PubMed

    Haider, Hani; Weisenburger, Joel N; Garvin, Kevin L

    2016-05-01

    (statistically significant, p < 0.001), and the coating wore away on all coated hips eventually. Higher friction mostly correlated with higher wear or damage to femoral heads or implant coatings, except for the highly cross-linked wear resistant ultrahigh-molecular-weight polyethylene which had slightly higher friction, confirming the same finding in other independent studies. This type of friction measurements can help screen for clamping and elevated wear of metal-on-metal and resurfacing total hip replacements, surgical malpositioning, and abraded and otherwise damaged surfaces. PMID:27160558

  3. [Pseudotumors caused by hip prostheses].

    PubMed

    Helkamaa, Teemu; Lohman, Martina; Alberty, Anne

    2015-01-01

    More than 100000 hip replacements have been performed in Finland. In the hip replacement operations performed due to osteoarthritis, the artificial joint surfaces are made of metal, plastic or ceramics. Pseudotumors associated with metal-on-metal (MoM) sliding surfaces have received worldwide attention. Soft issue lesions, not always symptomatic, may develop around the joint replacements. These may even require joint revision surgery. PMID:26237883

  4. New postlaser resurfacing medical treatment

    NASA Astrophysics Data System (ADS)

    Longo, Leonardo; Postiglione, Marco

    2000-06-01

    Today, laser resurfacing technique is codified. The purpose of our study is to reduce the post-intervention discomfort and the clinical signs. We tested a combination of pharmacological substances, applied as spray lotion and gel during and immediately after the intervention and the days after. We used this substances after laser resurfacing done with CO2 laser, Er:YAG laser and both. We noted a reduction statistically significant of the signs up described, with reduction of the recovery time. It is our opinion that this medical treatment must be done always, during and post laser resurfacing treatment.

  5. Anesthesia Methods in Laser Resurfacing

    PubMed Central

    Gaitan, Sergio; Markus, Ramsey

    2012-01-01

    Laser resurfacing technology offers the ability to treat skin changes that are the result of the aging process. One of the major drawbacks of laser resurfacing technologies is the pain associated with the procedure. The methods of anesthesia used in laser resurfacing to help minimize the pain include both noninvasive and invasive procedures. The noninvasive procedures can be divided into topical, cryoanesthesia, and a combination of both. The invasive methods of anesthesia include injected forms (infiltrative, nerve blocks, and tumescent anesthesia) and supervised anesthesia (monitored anesthesia care and general anesthesia). In this review, the authors summarize the types of anesthesia used in laser resurfacing to aid the provider in offering the most appropriate method for the patient to have as painless a procedure as possible. PMID:23904819

  6. The global resurfacing of Venus

    NASA Technical Reports Server (NTRS)

    Strom, Robert G.; Schaber, Gerald G.; Dawsow, Douglas D.

    1994-01-01

    The impact cratering record on Venus is unique among the terrestrial planets. Fully 84% of the craters are in pristine condition, and only 12% are fractured. Remarkably, only 2.5% of the craters and crater-related features are embayed by lava, although intense volcanism and tectonism have affected the entire planet. Furthermore, the spatial and hypsometric distribution of the craters is consistent with a completely random one, including stochastic variations. Monte Carlo simulations of equilibrium resurfacing models result in a minimum of 17 times more embayed craters than observed, or unobserved nonrandom crater distributions for resurfacing areas between 0.03% and 100% of the planet's surface. These models also are not consistent with the number and nonrandom distribution of volcanoes, and the nonrandom distribution of embayed and heavily fractured craters. The constraints imposed by the cratering record strongly indicate that Venus experienced a global resurfacing event about 300 m.y. ago followed by a dramatic reduction of volcanism and tectonism. This global resurfacing event ended abruptly (less than 10 m.y.). The present crater population has accumulated since then and remains largely intact. Thermal history models suggest that similar global resurfacing events probably occured episodically in the past. We show that neither the present level and style of geologic activity nor anything less than global resurfacing could have produced the observed cratering record. The effects of recent geologic activity are much less than those of the earlier global resurfacing event, when the record of all the early heavy bombardment and much of the later light bombardment was erased from the surface by massive volcanism and tectonic activity. Episodic regional resurfacing events that had global effects also occurred on Earth (e.g., the mid-Cretaceous superplume) and probably on Mars. On Mars they may have triggered the catastrophic releases of water that formed the outflow

  7. Resurfacing processes on Vesta

    NASA Astrophysics Data System (ADS)

    Krohn, K.; Jaumann, R.; Otto, K.; Elbeshausen, D.; Stephan, K.; Kneissl, T.; Schmedemann, N.; Roatsch, T.; Raymond, C.; Russell, C.

    2014-07-01

    Planetary surfaces are steadily modified by endogenic processes. The most important resurfacing processes on dry airless bodies are: mass-wasting processes, volcanic activity, and tectonics due to impact cratering. Due to the absence of volcanic activity on Vesta [1], mass wasting and impact cratering are the most likely resurfacing processes on Vesta. The high elevation differences on Vesta [2] and the steady bombardment of Vesta's surface by impacts cause seismic shaking which promote material to move downwards. We analyzed different types of mass-wasting features in the South Polar Region, such as slumping blocks at the steep scarp Matronalia Rupes, spur-and-gully morphologies, and landslides in craters [3]. Collapse processes, instability of slopes, and seismic-triggered events cause the landslides, rotational slumping blocks on scarps, as well as spur-and-gully morphologies on crater walls and scarps. Spur-and-gully morphology is known to form on Mars and the Earth normally supported by liquid flow but, on Vesta, these features formed under dry conditions. At Matronalia Rupes, rotational rock slumping blocks are clearly exposed as material slumped down the scarp wall in a stair-stepped pattern, which is interrupted by minor scarps and covers the underlying terrain. This rotational rock slumping is affected by slope instability and gravitationally triggered events, such as seismic shaking mostly produced by impacts elsewhere on Vesta [3]. The sloping surface of Vesta cause not only the formation of mass wasting features, but also the formation of craters on slopes. These craters are in turn influenced by mass wasting and show an asymmetric crater shape with a sharp uphill rim and a smooth downhill rim. The craters show a sharp crater rim uphill and a smooth one downhill as well as ejecta on the downhill rim and only thin ejecta over the uphill rim. Three-dimensional numerical simulations have been performed to study the formation process of the unusual craters

  8. New Insights into Wear and Biological Effects of Metal-on-Metal Bearings

    PubMed Central

    Catelas, Isabelle; Wimmer, Markus A.

    2011-01-01

    Background: Despite the renewed interest in metal-on-metal implants in the past two decades, the underlying wear mechanisms and biological effects are still not fully understood. Methods: This paper first reviews the tribology of metal-on-metal bearings, bringing new insights into the interaction of wear and corrosion, and putting the characteristics and the potential origin of wear particles in perspective with the proposed wear mechanisms. It then summarizes the current knowledge on the biological effects of particles and metal ions in relation to these wear mechanisms. Results: Tribochemical reactions play an important role in the wear of metal-on-metal joints. The generated tribomaterial, which progressively forms by mechanical mixing of the uppermost nanocrystalline zone of the metal surface with proteins from the synovial fluid, governs the wear rate and influences the corrosive behavior of the bearing. Nanometer-sized wear particles may initially originate from the passivation layer covering the implant surface and then detach from this tribolayer. The inflammatory response observed surrounding metal-on-metal implants appears to be lower than that around metal-on-polyethylene implants. However, metallic byproducts, which can complex with proteins, may lead to a T lymphocyte-mediated hypersensitivity response. Conclusions: The tribolayer appears to have beneficial effects on the wear rate. Much information has been gained on wear particle characteristics, but the exact mechanisms of particle detachment remain to be further elucidated. Excessive wear along with a hypersensitivity response may be at the origin of the early adverse tissue reactions that have been recently reported in some patients with metal-on-metal implants. Clinical Relevance: Future development of new methods to improve the tribolayer retention and optimize the tribocorrosive properties of the implant may minimize the clinical impact of implant wear and immune responses. PMID:21543694

  9. What would you do?: challenges in hip surgery.

    PubMed

    Lombardi, A V; Cameron, H U; Della Valle, C J; Jones, R E; Paprosky, W G; Ranawat, C S

    2012-11-01

    A moderator and panel of five experts led an interactive session in discussing five challenging and interesting patient case presentations involving surgery of the hip. The hip pathologies reviewed included failed open reduction internal fixation of subcapital femoral neck fracture, bilateral hip disease, evaluation of pain after metal-on-metal hip arthroplasty, avascular necrosis, aseptic loosening secondary to osteolysis and polyethylene wear, and management of ceramic femoral head fracture.

  10. Worse health-related quality of life and hip function in female patients with elevated chromium levels

    PubMed Central

    Hussey, Daniel K; Madanat, Rami; Donahue, Gabrielle S; Rolfson, Ola; Muratoglu, Orhun K; Malchau, Henrik

    2016-01-01

    Background and purpose Blood metal ion levels can be an indicator for detecting implant failure in metal-on-metal (MoM) hip arthroplasties. Little is known about the effect of bilateral MoM implants on metal ion levels and patient-reported outcomes. We compared unilateral patients and bilateral patients with either an ASR hip resurfacing (HR) or an ASR XL total hip replacement (THR) and investigated whether cobalt or chromium was associated with a broad spectrum of patient outcomes. Patients and methods From a registry of 1,328 patients enrolled in a multicenter prospective follow-up of the ASR Hip System, which was recalled in 2010, we analyzed data from 659 patients (311 HR, 348 THR) who met our inclusion criteria. Cobalt and chromium blood metal ion levels were measured and a 21-item patient-reported outcome measures (PROMs) questionnaire was used mean 6 years after index surgery. Results Using a minimal threshold of ≥7 ppb, elevated chromium ion levels were found to be associated with worse health-related quality of life (HRQoL) (p < 0.05) and hip function (p < 0.05) in women. These associations were not observed in men. Patients with a unilateral ASR HR had lower levels of cobalt ions than bilateral ASR HR patients (p < 0.001) but similar levels of chromium ions (p = 0.09). Unilateral ASR XL THR patients had lower chromium and cobalt ion levels (p < 0.005) than bilateral ASR XL THR patients. Interpretation Chromium ion levels of ≥7 ppb were associated with reduced functional outcomes in female MoM patients. PMID:27459602

  11. Analysis of nonablative skin resurfacing

    NASA Astrophysics Data System (ADS)

    Milner, Thomas E.; Anvari, Bahman; Keikhanzadeh, Kurosh; Dave, Digant P.; Nelson, J. Stuart; Goodman, Dennis M.; Hennings, David R.; Baumgardner, John; Berry, Michael J.

    1997-05-01

    Nonablative skin resurfacing is a dermatologic procedure utilizing pulsed laser irradiation and dynamic cooling to induce selectively a wound healing response in the papillary and upper reticular dermis. Using temperature measurements of human skin provided by pulsed photothermal radiometry immediately following laser irradiation (lambda equals 1.32 micrometer), spatial distribution of thermal damage is predicted in response to various potential therapeutic laser- cryogen doses. Results of our analysis suggest that appropriate application of pulsed laser irradiation and cryogen spray cooling may be used to protect the epidermis and selectively confine thermal injury to the papillary and upper reticular dermis. Development of nonablative skin resurfacing will require understanding the relationship between the degree of dermal photocoagulation and the cutaneous wound healing response following laser irradiation.

  12. Friction in metal-on-metal total disc arthroplasty: effect of ball radius.

    PubMed

    Moghadas, Parshia; Mahomed, Aziza; Hukins, David W L; Shepherd, Duncan E T

    2012-02-01

    Total disc arthroplasty (TDA) can be used to replace a degenerated intervertebral disc in the spine. There are different designs of prosthetic discs, but one of the most common is a ball-and-socket combination. Contact between the bearing surfaces can result in high frictional torque, which can then result in wear and implant loosening. This study was designed to determine the effects of ball radius on friction. Generic models of metal-on-metal TDA were manufactured with ball radii of 10, 12, 14 and 16 mm, with a radial clearance of 0.015 mm. A simulator was used to test each sample in flexion-extension, lateral bending and axial rotation at frequencies of 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75 and 2 Hz under loads of 50, 600, 1200 and 2000 N, in new born calf serum. Frictional torque was measured and Stribeck curves were plotted to illustrate the lubrication regime in each case. It was observed that implants with a smaller ball radius showed lower friction and showed boundary and mixed lubrication regimes, whereas implants with larger ball radius showed boundary lubrication only. This study suggests designing metal-on-metal TDAs with ball radius of 10 or 12 mm, in order to reduce wear and implant loosening.

  13. Skin resurfacing procedures: new and emerging options

    PubMed Central

    Loesch, Mathew M; Somani, Ally-Khan; Kingsley, Melanie M; Travers, Jeffrey B; Spandau, Dan F

    2014-01-01

    The demand for skin resurfacing and rejuvenating procedures has progressively increased in the last decade and has sparked several advances within the skin resurfacing field that promote faster healing while minimizing downtime and side effects for patients. Several technological and procedural skin resurfacing developments are being integrated into clinical practices today allowing clinicians to treat a broader range of patients’ skin types and pathologies than in years past, with noteworthy outcomes. This article will discuss some emerging and developing resurfacing therapies and treatments that are present today and soon to be available. PMID:25210469

  14. Review of cobalt toxicokinetics following oral dosing: Implications for health risk assessments and metal-on-metal hip implant patients.

    PubMed

    Tvermoes, Brooke E; Paustenbach, Dennis J; Kerger, Brent D; Finley, Brent L; Unice, Kenneth M

    2015-05-01

    Cobalt (Co) can stimulate erythropoietin production in individuals at doses exceeding 25 mg CoCl2/day. Co has also been shown to exert effects on the thyroid gland, heart and nervous system at sufficient doses. The biological activity of Co is dictated by the concentration of free (unbound) ionic Co(2+). Blood concentrations, as well as, urinary excretion rates of Co are reliable biomarkers for systemic Co exposure. A recent series of human volunteer Co-supplement studies simultaneously measured Co blood and urine concentrations, as well as, Co speciation in serum, and a number of biochemical and clinical parameters. It was found in these studies that peak Co whole blood concentration as high as 117 μg/L were not associated with changes in hematological parameters such as increased red blood cell (RBC) count, hemoglobin (Hgb) or hematocrit (Hct) levels, nor with changes in cardiac, neurological or, thyroid function. Using a Co biokinetic model, the estimated Co systemic tissue concentrations (e.g., liver, kidney, and heart) following 90-days of Co-dietary supplementation with ∼1 mg Co/day were found to be similar to estimated tissue concentrations in implant patients after 10 years of exposure at continuous steady state Co blood concentration of ∼10 μg/L. This study is the first to present modeled Co tissue concentrations at various doses following sub-chronic and chronic exposure. The modeled steady state tissue Co concentrations in combination with the data on adverse health effects in humans should help in the characterization of potential hazards associated with increased blood Co concentrations due to exposure to dietary supplements or cobalt-chromium (Co-Cr) containing implants.

  15. The Interchangeability of Plasma and Whole Blood Metal Ion Measurement in the Monitoring of Metal on Metal Hips

    PubMed Central

    Malek, Ibrahim A.; Rogers, Joanne; King, Amanda Christina; Clutton, Juliet; Winson, Daniel; John, Alun

    2015-01-01

    One hundred and twenty six paired samples of plasma and whole blood were measured with inductively coupled plasma mass spectrometry technique for metal ions analysis to determine a relationship between them. There was a significant difference between the mean plasma and whole blood concentrations of both cobalt (Co) and chromium (Cr) (p < 0.0001 for both Co and Cr). The mean ratio between plasma and whole blood Cr and Co was 1.56 (range: 0.39–3.85) and 1.54 (range: 0.64–18.26), respectively, but Bland and Altman analysis illustrated that this relationship was not universal throughout the range of concentrations. There was higher variability at high concentrations for both ions. We conclude that both these concentrations should not be used interchangeably and conversion factors are unreliable due to concentration dependent variability. PMID:26798516

  16. Laser Resurfacing: Full Field and Fractional.

    PubMed

    Pozner, Jason N; DiBernardo, Barry E

    2016-07-01

    Laser resurfacing is a very popular procedure worldwide. Full field and fractional lasers are used in many aesthetic practices. There have been significant advances in laser resurfacing in the past few years, which make patient treatments more efficacious and with less downtime. Erbium and carbon dioxide and ablative, nonablative, and hybrid fractional lasers are all extremely effective and popular tools that have a place in plastic surgery and dermatology offices. PMID:27363765

  17. Resurfacing history of Tempe Terra and surroundings

    SciTech Connect

    Frey, H.V. ); Grant, T.D. )

    1990-08-30

    The resurfacing history of the Tempe Terra region is determined using the Neukum and Hiller technique of breaking cumulative frequency curves into separate branches where the curves depart from a standard production curve. We find four surfaces recorded in the heavily cratered portions of Tempe Terra, with crater retention ages N(1) = (242,100), (95,700), (20,800), and (5,500). This is interpreted to indicate three major resurfacing events occurred in this region, ending at N(1) = (95,700), (20,800), and (5,500). The ridged plains on the Tempe Terra plateau have an oldest recorded surface age of (20,400), identical to that of the second resurfacing event recorded in the heavily cratered areas. A single resurfacing of the ridged plains (which may have been a second episode of ridged plains volcanism) occurred at N(1) = (7,800). The knobby plains to the north west and east of Tempe Terra also show a resurfacing at (20,000) and additional events at (5,400) and perhaps (1,600). Mottled plains to the northeast record surfaces with crater retention age (7,500), (5,000), and (3,900), where the first age is determined by a single surviving crater. It appears that the Lunae Planum Age (LPA) (at N(1) = (20,000)) resurfacing event seen elsewhere on mars was widespread and effective in this region. A second widespread event appears to have ended at N(1) = (5,000). The authors estimate the thickness of the resurfacing materials corresponding to the LPA event to be less than 90 m in the heavily cratered areas but 300-500 m in the ridged plains themselves. Later resurfacing materials were generally thicker farther north in the mottled plains (300 m) than in the knobby plains (200 m).

  18. A tectonic resurfacing model for Venus

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.

    1993-01-01

    Two remarkable aspects of the population of impact craters on Venus are that craters at all sizes are indistinguishable from a random population and that the vast majority of craters have not been significantly modified by tectonic strain or by volcanic flows external to the crater rim, despite evidence from Magellan images that volcanic and tectonic features are widespread on Venus. One interpretation of these observations is that most of the surface dates from the end of a catastrophic global resurfacing event that ceased about 500 My ago, and that the small fraction of craters volcanically embayed or modified by deformation indicates that volcanic and tectonic activity subsequent to that time has been at much lower levels. An alternative model, in which resurfacing occurs episodically in patches a few hundred kilometers in extent and there is a wider spectrum of surface ages, also appears to be consistent with the characteristics of impact craters on Venus. A number of potential mechanisms for catastrophic resurfacing of Venus have been proposed, ranging from geologically sudden convective destabilization of the global lithosphere to strongly time-dependent heat flux and melt generation in the underlying mantle. In most of these geophysical models, resurfacing occurs implicitly or explicitly by volcanism. We explore the hypothesis that, at least in the geologically recent history of Venus, the primary resurfacing mechanism has been tectonic deformation rather than volcanism. We show how such a hypothesis provides at least as good an explanation of a wide range of observations as do volcanic resurfacing models. Finally, we explore the implications of tectonic resurfacing hypothesis for the controversy over the recent resurfacing history of the planet.

  19. Histopathology of laser skin resurfacing

    NASA Astrophysics Data System (ADS)

    Thomsen, Sharon L.; Baldwin, Bonnie; Chi, Eric; Ellard, Jeff; Schwartz, Jon A.

    1997-05-01

    Pulsed carbon-dioxide laser skin resurfacing is a purportedly 'non-thermal' procedure enjoying wide application as a cosmetic treatment for skin wrinkles. Treatment success has been based on clinical assessments of skin smoothness. Skin lesions (1 cm2) created by one, two or three superimposed carbon-dioxide laser passes were placed on the backs of 28 'fuzzy' Harlan Sprague Dawley rats. The variable laser irradiation parameters included measured energies ranging from 112 to 387/pulse with pulse widths of 65 and 125 microseconds and a repetition rate of 8 Hz. The square, flat laser beam measured 3 mm2 at the focal point. The lesions were collected from 0 to 10 days after treatment for qualitative and quantitative histopathology. Thermal damage and treatment effect tended to increase in severity and, to a lesser extent, depth with increased delivery parameters. In acute lesions, the vacuolated and fragmented, desiccated and thermally coagulated epidermis was partially removed exposing the underlying thermally coagulated dermal collagen and cells. Epidermal and dermal necrosis and slough occurred between 24 to 72 hours after treatment. Epithelial regeneration originated from the adnexa and the lesion edges. Dermal fibrous scar formation began at 5 days below the regenerated epidermis and became more prominent at 7 and 10 days.

  20. Early Outcomes Following Metal-on-Metal Reverse Total Shoulder Arthroplasty in Patients Younger Than 50 Years.

    PubMed

    Riley, Clay; Idoine, John; Shishani, Yousef; Gobezie, Reuben; Edwards, Bradley

    2016-09-01

    Reverse total shoulder arthroplasty (TSA) is a useful intervention for older patients with glenohumeral arthritis and a deficient rotator cuff. However, as a semiconstrained prosthesis, conventional reverse TSA implanted in a young patient could fail over time secondary to polyethylene wear and subsequent osteolysis. A metal-on-metal prosthesis may avoid this type of failure. The purpose of this study is to assess the outcomes in an initial cohort of young patients who underwent reverse TSA using a metal-on-metal prosthesis. Surgical indications included age younger than 50 years with a functioning deltoid and significant impairment of shoulder function with irreparable rotator cuff due to tumor resection, arthritis, or revision surgery. Nine patients with an average age of 37 years underwent implantation of a custom metal-on-metal reverse TSA prosthesis. All patients had a minimum 12-month follow-up or a failure of their procedure requiring revision surgery prior to 1 year. American Shoulder and Elbow Surgeons (ASES) scores, Constant scores, and range of motion were recorded and analyzed pre- and postoperatively to assess improvement, and all complications were noted. Average ASES score improved from 47 points preoperatively to 73.4 points postoperatively (P=.013). Average Constant and adjusted Constant scores improved from 20.8 points and 16% preoperatively to 61.8 points and 67.3% postoperatively, respectively (P=.019 and P=.068). Mean postoperative active forward flexion and active external rotation were 119.4° and 10°, respectively. Complications included the following: 3 patients sustained a postoperative dislocation, 1 patient had a glenoid fracture and complete loss of fixation of the baseplate, and 1 patient experienced dissociation of the glenosphere from the base-plate. Although metal-on-metal reverse TSA may appear to be an attractive choice in the treatment of young patients with limited reconstructive options, postoperative outcomes are

  1. Profiling the third-body wear damage produced in CoCr surfaces by bone cement, CoCr, and Ti6Al4V debris: a 10-cycle metal-on-metal simulator test.

    PubMed

    Halim, Thomas; Burgett, Michelle; Donaldson, Thomas K; Savisaar, Christina; Bowsher, John; Clarke, Ian C

    2014-07-01

    Particles of bone cement (polymethyl methacrylate), CoCr and Ti6Al4V were compared for their abrasion potential against CoCr substrates. This appears to be the first study utilizing CoCr and Ti6Al4V particulates to abrade CoCr bearings and the first study profiling the morphology of third-body abrasive wear scratches in a hip simulator. The 5 mg debris allotments (median size range 140-300 µm) were added to cups mounted both inverted and anatomically with metal-on-metal (MOM) bearings in a 10-cycle, hip simulator test. Surface abrasion was characterized by roughness indices and scratch profiles. Compared to third-body abrasion with metal debris, polymethyl methacrylate debris had minimal effect on the CoCr surfaces. In all, 10 cycles of abrasion with metal debris demonstrated that roughness indices (Ra, PV) increased approximately 20-fold from the unworn condition. The scratch profiles ranged 20-108 µm wide and 0.5-2.8 µm deep. The scratch aspect ratio (W/PV) averaged 0.03, and this very low ratio indicated that the 140 µm CoCr beads had plastically deformed to create wide but shallow scratches. There was no evidence of transfer of CoCr beads to CoCr bearings. The Ti64 particles produced similar scratch morphology with the same aspect ratio as the CoCr particulates. However, the titanium particulates also showed a unique ability to flatten and adhere to the CoCr, forming smears and islands of contaminating metal on the CoCr bearings. The morphology of scratches and metal transfer produced by these large metal particulates in the simulator appeared identical to those reported on retrieved metal-on-metal bearings.

  2. A numerical study of failure mechanisms in the cemented resurfaced femur: effects of interface characteristics and bone remodelling.

    PubMed

    Pal, B; Gupta, S; New, A M

    2009-05-01

    Failure mechanisms of the resurfaced femoral head include femoral neck fracture in the short-term and stress shielding and implant loosening in the long-term. In this study, finite element simulations of the resurfaced femur considering a debonded implant-cement interface, variable stem-bone interface conditions, and bone remodelling were used to study load transfer within the resurfaced femur and to investigate its relationship with known failure mechanisms. Realistic three-dimensional finite element models of an intact and resurfaced femur were used. Various conditions at the interface between the stem of the prosthesis and the bone were considered. Loading conditions included normal walking and stair climbing. For all stem-bone contact conditions, the tensile stresses in the cement mantle varied between 1 MPa and 5.4 MPa, except near the distal rim of the resurfacing component where they reached 5.4-7MPa. In the case of full stem-bone contact, high von Mises stresses (114-121MPa) were generated in the implant at the stem-cup junction. These stresses were considerably reduced (maximum von Mises stress, 76 MPa) where a gap was present at the stem-bone interface. Resurfacing led to strain shielding of the bone of the femoral head (20-75 per cent strain reductions) and periprosthetic bone resorption (50-80 per cent bone density reductions) for all interface stem-bone contact conditions. In the lateral femoral head and the proximal femoral shaft around the trochantric region, bone density reductions varied between 10 per cent and 50 per cent. Bone apposition was observed in the inferior-medial part of the femoral head and proximal femoral neck region. For full stem-bone contact, more load was transferred through the stem to the surrounding bone, exacerbating strain shielding. Although femoral hip resurfacing conserves bone stock at the primary operation, strain shielding and periprosthetic bone resorption might lead to eventual loosening over time. Post

  3. Revision of failed humeral head resurfacing arthroplasty

    PubMed Central

    Streubel, Philipp N.; Simone, Juan P.; Cofield, Robert H.; Sperling, John W.

    2016-01-01

    Purpose: The purpose of this study is to assess the outcomes of a consecutive series of patients who underwent revision surgery after humeral head resurfacing (HHR). Our joint registry was queried for all patients who underwent revision arthroplasty for failed HHR at our institution from 2005 to 2010. Eleven consecutive patients (average age 54 years; range 38-69 years) that underwent revision of 11 resurfacing arthroplasties were identified. The primary indication for resurfacing had been osteoarthritis in six, glenoid dysplasia in two, a chondral lesion in two, and postinstability arthropathy in one patient. The indication for revision was pain in 10 and infection in one patient. Seven patients had undergone an average of 1.9 surgeries prior to resurfacing (range 1-3). Materials and Methods: All patients were revised to stemmed arthroplasties, including one hemiarthroplasty, two reverse, and eight anatomic total shoulder arthroplasties at a mean 33 months after primary resurfacing (range 10-131 months). A deltopectoral approach was used in seven patients; four patients required an anteromedial approach due to severe scarring. Subscapularis attenuation was found in four cases, two of which required reverse total shoulder arthroplasty. Bone grafting was required in one glenoid and three humeri. Results: At a mean follow-up of 3.5 years (range 1.6-6.9 years), modified Neer score was rated as satisfactory in five patients and unsatisfactory in six. Abduction and external rotation improved from 73° to 88° (P = 0.32) and from 23° to 32° (P = 0.28) respectively. Reoperation was required in two patients, including one hematoma and one revision for instability. Conclusion: Outcomes of revision of HHR arthroplasty in this cohort did not improve upon those reported for revision of stemmed humeral implants. A comparative study would be required to allow for definitive conclusions to be made. PMID:26980986

  4. Maximum temperatures of 89°C recorded during the mechanical preparation of 35 femoral heads for resurfacing

    PubMed Central

    2011-01-01

    Background and purpose We noticed that our instruments were often too hot to touch after preparing the femoral head for resurfacing, and questioned whether the heat generated could exceed temperatures known to cause osteonecrosis. Patients and methods Using an infra-red thermal imaging camera, we measured real-time femoral head temperatures during femoral head reaming in 35 patients undergoing resurfacing hip arthroplasty. 7 patients received an ASR, 8 received a Cormet, and 20 received a Birmingham resurfacing arthroplasty. Results The maximum temperature recorded was 89°C. The temperature exceeded 47°C in 28 patients and 70°C in 11. The mean duration of most stages of head preparation was less than 1 min. The mean time exceeded 1 min only on peripheral head reaming of the ASR system. At temperatures lower than 47°C, only 2 femoral heads were exposed long enough to cause osteonecrosis. The highest mean maximum temperatures recorded were 54°C when the proximal femoral head was resected with an oscillating saw and 47°C during peripheral reaming with the crown drill. The modified new Birmingham resurfacing proximal femoral head reamer substantially reduced the maximum temperatures generated. Lavage reduced temperatures to a mean of 18°C. Interpretation 11 patients were subjected to temperatures sufficient to cause osteonecrosis secondary to thermal insult, regardless of the duration of reaming. In 2 cases only, the length of reaming was long enough to induce damage at lower temperatures. Lavage and sharp instruments should reduce the risk of thermal insult during hip resurfacing. PMID:22066558

  5. Biomechanical optimization of subject-specific implant positioning for femoral head resurfacing to reduce fracture risk.

    PubMed

    Miles, Brad; Kolos, Elizabeth; Appleyard, Richard; Theodore, Willy; Zheng, Keke; Li, Qing; Ruys, Andrew J

    2016-07-01

    Peri-prosthetic femoral neck fracture after femoral head resurfacing can be either patient-related or surgical technique-related. The study aimed to develop a patient-specific finite element modelling technique that can reliably predict an optimal implant position and give minimal strain in the peri-prosthetic bone tissue, thereby reducing the risk of peri-prosthetic femoral neck fracture. The subject-specific finite element modelling was integrated with optimization techniques including design of experiments to best possibly position the implant for achieving minimal strain for femoral head resurfacing. Sample space was defined by varying the floating point to find the extremes at which the cylindrical reaming operation actually cuts into the femoral neck causing a notch during hip resurfacing surgery. The study showed that the location of the maximum strain, for all non-notching positions, was on the superior femoral neck, in the peri-prosthetic bone tissue. It demonstrated that varus positioning resulted in a higher strain, while valgus positioning reduced the strain, and further that neutral version had a lower strain. PMID:27098752

  6. Early outcomes of patella resurfacing in total knee arthroplasty

    PubMed Central

    Clements, Warren J; Miller, Lisa; Whitehouse, Sarah L; Graves, Stephen E; Ryan, Philip

    2010-01-01

    Background Patella resurfacing in total knee arthroplasty is a contentious issue. The literature suggests that resurfacing of the patella is based on surgeon preference, and little is known about the role and timing of resurfacing and how this affects outcomes. Methods We analyzed 134,799 total knee arthroplasties using data from the Australian Orthopaedic Association National Joint Replacement Registry. Hazards ratios (HRs) were used to compare rates of early revision between patella resurfacing at the primary procedure (the resurfacing group, R) and primary arthroplasty without resurfacing (no-resurfacing group, NR). We also analyzed the outcomes of NR that were revised for isolated patella addition. Results At 5 years, the R group showed a lower revision rate than the NR group: cumulative per cent revision (CPR) 3.1% and 4.0%, respectively (HR = 0.75, p < 0.001). Revisions for patellofemoral pain were more common in the NR group (17%) than in the R group (1%), and “patella only” revisions were more common in the NR group (29%) than in the R group (6%). Non-resurfaced knees revised for isolated patella addition had a higher revision rate than patella resurfacing at the primary procedure, with a 4-year CPR of 15% and 2.8%, respectively (HR = 4.1, p < 0.001). Interpretation Rates of early revision of primary total knees were higher when the patella was not resurfaced, and suggest that surgeons may be inclined to resurface later if there is patellofemoral pain. However, 15% of non-resurfaced knees revised for patella addition are re-revised by 4 years. Our results suggest an early beneficial outcome for patella resurfacing at primary arthroplasty based on revision rates up to 5 years. PMID:19968604

  7. The change of resurfacing regimes on Venus

    NASA Astrophysics Data System (ADS)

    Ivanov, M. A.

    2015-01-01

    The change of volcanic resurfacing regimes on Venus is discussed. The frequency-size distribution of the regional and lobate plains fields suggest that regional plains had likely been formed due to lava flooding. The geological ratios of impact craters with plains units of different ages are analyzed. Only 3% of the craters located on the older regional plains are found to be embayed by plains material. About 50% of the craters located on the younger lobate plains are found to be embayed by plains lavas. Both the frequency-size distribution of the regional plains fields and the number of embayed craters indicate their catastrophic formation. For lobate plains, these parameters indicate a gradual and time-stretched accumulation of their material. Thus, the volcanic resurfacing regimes must have been changing radically throughout the observable portion of the geological history of Venus.

  8. Patellofemoral resurfacing at total knee arthroplasty.

    PubMed

    Harwin, S F; Stein, A J; Stern, R E

    1994-10-01

    A retrospective review of 268 primary total knee arthroplasties (TKAs) with a mean follow-up of four years is presented. The patellae were resurfaced in all cases. There were six complications (2.2%) referable to the patellofemoral articulation: three subluxations, one patellar fracture, one loosening of a metal-backed patellar component, and one patellar tendon avulsion. Successful patellofemoral resurfacing (PFR) can be accomplished with minimal complications if the following technical considerations are met: 5-7 degrees of valgus alignment; medial placement of the patellar component; taking care not to increase either the AP diameter of the knee or the thickness of the patella; avoiding internal rotation of either the tibial or femoral components and proper soft tissue balancing. A thorough review of patellofemoral complications after TKA is presented, and technical considerations relevant to the successful performance of PFR are discussed.

  9. Skin resurfacing using an ultrasonic surgical aspirator

    NASA Astrophysics Data System (ADS)

    Lawes, Kate; Thomsen, Sharon L.; Nolan, Kathy; Carr, Jan; Kennedy, Jenifer S.

    1998-07-01

    The ultrasonic aspirator is essentially a vibrating tip whose ultrasonic frequencies fragment soft tissues, before aspirating it away from the surgical field. In the case of skin, the softer epidermis absorbs the vibrating tip's impact force so as to fragment it, whereas the more elastic and collagenous dermis reflects it. Understanding this, a chronic study to compare a skin resurfacing laser (Coherent, Palo Alto, CA) and an ultrasonic surgical aspirator (CUSA) (Valleylab Inc., Boulder, CO) as a skin resurfacing tool was performed using an in-vivo pigmented porcine model. Gross and histopathologic evaluations were made of the lesions removed at 0, 1, 3, 6, 11, 21, and 56 days post procedure. The laser parameters utilized constant power (60 W) and spot size but the number of passes was varied from 1 to 4 passes. This simulated typical minimal to maximal clinical laser treatments. CUSA parameters were then chosen so as to imitate the various laser passes. On sacrifice gross evaluations showed similar levels of healing, using lesion color and scab formation as the method of evaluation. Histological analysis showed evidence of thermal effects with both devices and that some but not all CUSA settings were comparable to the laser. In short, ultrasonic technology may have the potential to provide a controlled method of selectively removing the epidermal skin layer during resurfacing.

  10. In vitro friction and lubrication of large bearing hip prostheses.

    PubMed

    Flanagan, S; Jones, E; Birkinshaw, C

    2010-01-01

    New material combinations and designs of artificial hip implants are being introduced in an effort to improve proprioception and functional longevity. Larger joints in particular are being developed to improve joint stability, and it is thought that these larger implants will be more satisfactory for younger and more physically active patients. The study detailed here used a hip friction simulator to assess the friction and lubrication properties of large-diameter hip bearings of metal-on-metal and ceramic-on-reinforced-polymer couplings. Joints of different diameters were evaluated to determine what effect, if any, bearing diameter had on lubrication. In addition, the effects of lubricant type are considered, using carboxymethyl cellulose and bovine calf serum, and the physiological lubricant is shown to be considerably more effective at reducing friction. The frictional studies showed that the metal-on-metal joints worked under a mixed lubrication regime, producing similar friction factor values to each other. The addition of bovine calf serum (BCS) reduced the friction. The ceramic-on-reinforced-polymer samples were shown to operate with high friction factors and mixed lubrication. When tested with BCS, the larger-diameter bearings showed a decrease in friction compared with the smaller-size bearings, and the addition of BCS resulted in an increase in friction, unlike the metal-on-metal system. The study demonstrated that the component's diameter had little or no influence on the lubrication and friction of the large bearing combinations tested.

  11. Mid-term clinical results of total hip arthroplasty using a Wagner standard cup for dysplastic hip

    PubMed Central

    Maezawa, Katsuhiko; Nozawa, Masahiko; Yuasa, Takahito; Aritomi, Kentaro; Ogawa, Seiki; Maruyama, Yuichiro; Kaneko, Kazuo

    2014-01-01

    Background The outcome of cementless total hip arthroplasty depends on many factors. We must not forget fundamental things those are design of outer surface of the component, that leads bone ingrowth into the prosthesis, better initial stability, and better insertional techniques. The purpose of this study was to review our experience with metal-on-metal total hip arthroplasty with a Wagner standard cup for patients who had acetabular dysplasia. Patients and methods Fifty-four patients with 55 hips underwent primary metal-on-metal total hip arthroplasty (Metasul prosthesis) with a Wagner standard cup (44–48 mm in outer diameter) and were followed for a minimum of 10 years. All patients received the same type of cementless femoral component (Natural hip stem) and femoral head (28 mm in diameter). Results Seventeen of the 55 Wagner standard cups (30.9%) showed aseptic loosening over a mean period of 3.6 years after surgery, and there were no bone anchors on the outer surface of the 16 retrieved cups. Conclusion From our experience, the small Wagner standard cup does not achieve sufficient osteointegration and we do not recommend the use of this cup, especially for patients with acetabular dysplasia and/or those with a small stature. PMID:25561751

  12. Hip Replacement

    MedlinePlus

    ... surgeon removes damaged cartilage and bone from your hip joint and replaces them with new, man-made parts. A hip replacement can Relieve pain Help your hip joint work better Improve walking and other movements The ...

  13. Plasma skin resurfacing: personal experience and long-term results.

    PubMed

    Bentkover, Stuart H

    2012-05-01

    This article presents a comprehensive clinical approach to plasma resurfacing for skin regeneration. Plasma technology, preoperative protocols, resurfacing technique, postoperative care, clinical outcomes, evidence-based results, and appropriate candidates for this procedure are discussed. Specific penetration depth and specific laser energy measurements are provided. Nitrogen plasma skin regeneration is a skin-resurfacing technique that offers excellent improvement of mild to moderate skin wrinkles and overall skin rejuvenation. It also provides excellent improvement in uniformity of skin color and texture in patients with hyperpigmentation with Fitzpatrick skin types 1 through 4. PMID:22537783

  14. Plasma skin resurfacing: personal experience and long-term results.

    PubMed

    Bentkover, Stuart H

    2012-05-01

    This article presents a comprehensive clinical approach to plasma resurfacing for skin regeneration. Plasma technology, preoperative protocols, resurfacing technique, postoperative care, clinical outcomes, evidence-based results, and appropriate candidates for this procedure are discussed. Specific penetration depth and specific laser energy measurements are provided. Nitrogen plasma skin regeneration is a skin-resurfacing technique that offers excellent improvement of mild to moderate skin wrinkles and overall skin rejuvenation. It also provides excellent improvement in uniformity of skin color and texture in patients with hyperpigmentation with Fitzpatrick skin types 1 through 4.

  15. Liquid water and active resurfacing on Europa

    NASA Technical Reports Server (NTRS)

    Squyres, S. W.; Reynolds, R. T.; Cassen, P. M.; Peale, S. J.

    1983-01-01

    Arguments for recent resurfacing of Europa by H2O from a liquid layer are presented, based on new interpretations of recent spacecraft and earth-based observations and revised theoretical calculations. The heat flow in the core and shell due to tidal forces is discussed, and considerations of viscosity and convection in the interior are found to imply water retention in the outer 60 km or so of the silicates, forming a layer of water/ice many tens of km thick. The outer ice crust is considered to be too thin to support heat transport rates sufficient to freeze the underlying water. Observational evidence for the calculations would consist of an insulating layer of frosts derived from water boiling up between cracks in the surface crust. Evidence for the existence of such a frost layer, including the photometric function of Europa and the deposits of sulfur on the trailing hemisphere, is discussed.

  16. Biotribology of artificial hip joints

    PubMed Central

    Di Puccio, Francesca; Mattei, Lorenza

    2015-01-01

    Hip arthroplasty can be considered one of the major successes of orthopedic surgery, with more than 350000 replacements performed every year in the United States with a constantly increasing rate. The main limitations to the lifespan of these devices are due to tribological aspects, in particular the wear of mating surfaces, which implies a loss of matter and modification of surface geometry. However, wear is a complex phenomenon, also involving lubrication and friction. The present paper deals with the tribological performance of hip implants and is organized in to three main sections. Firstly, the basic elements of tribology are presented, from contact mechanics of ball-in-socket joints to ultra high molecular weight polyethylene wear laws. Some fundamental equations are also reported, with the aim of providing the reader with some simple tools for tribological investigations. In the second section, the focus moves to artificial hip joints, defining materials and geometrical properties and discussing their friction, lubrication and wear characteristics. In particular, the features of different couplings, from metal-on-plastic to metal-on-metal and ceramic-on-ceramic, are discussed as well as the role of the head radius and clearance. How friction, lubrication and wear are interconnected and most of all how they are specific for each loading and kinematic condition is highlighted. Thus, the significant differences in patients and their lifestyles account for the high dispersion of clinical data. Furthermore, such consideration has raised a new discussion on the most suitable in vitro tests for hip implants as simplified gait cycles can be too far from effective implant working conditions. In the third section, the trends of hip implants in the years from 2003 to 2012 provided by the National Joint Registry of England, Wales and Northern Ireland are summarized and commented on in a discussion. PMID:25621213

  17. Erbium:YAG laser resurfacing using a novel portable device.

    PubMed

    Gordon, James; Khan, Misbah H; Khatri, Khalil A

    2007-05-01

    Laser resurfacing of facial rhytids has become a popular treatment for many patients who have wrinkles, photodamage, and acne scarring. Erbium:YAG laser resurfacing has emerged as one of the safer, more effective methods of facial rejuvenation and its increasing popularity has led to its widespread use for resurfacing. However, size and high initial and maintenance cost are among the problems with currently available laser devices. The LightPod portable Erbium:YAG laser from Aerolase offers a new paradigm for more cost effective means of performing ablative resurfacing with reduced initial and maintenance cost and the ease of portability with significantly reduced size and weight. The objective of this pilot study was to analyze the efficacy of The LightPod Erbium:YAG laser in different skin types for various indications.

  18. Prosthetic hip-associated cobalt toxicity.

    PubMed

    Pizon, Anthony F; Abesamis, Michael; King, Andrew M; Menke, Nathan

    2013-12-01

    Prosthetic hip-associated cobalt toxicity (PHACT) is gaining recognition due to the use of metal-on-metal total hip replacements. Identifying true toxicity from merely elevated cobalt levels can be extremely difficult due to the lack of available data. An extensive review of the medical literature was undertaken to characterize cobalt toxicity from prosthetic hips. As an objective approach to making the diagnosis of PHACT, we suggest the following criteria: (1) elevated serum or whole blood cobalt levels due to a prosthetic hip, (2) at least two test-confirmed findings consistent with cobalt toxicity, and (3) exclusion of other etiologies. Adhering to objective diagnostic data for PHACT is a realistic and prudent method by which to eliminate the subjectivity of vague or difficult to identify complaints. These diagnostic criteria are not meant to evaluate prosthetic hardware failure, but as a means to identify systemic cobalt toxicity. Finally, assessment of cobalt toxicity from prosthetic hips should be done in conjunction with a medical toxicologist. PMID:24258006

  19. Hip instability.

    PubMed

    Smith, Matthew V; Sekiya, Jon K

    2010-06-01

    Hip instability is becoming a more commonly recognized source of pain and disability in patients. Traumatic causes of hip instability are often clear. Appropriate treatment includes immediate reduction, early surgery for acetabular rim fractures greater than 25% or incarcerated fragments in the joint, and close follow-up to monitor for avascular necrosis. Late surgical intervention may be necessary for residual symptomatic hip instability. Atraumatic causes of hip instability include repetitive external rotation with axial loading, generalized ligamentous laxity, and collagen disorders like Ehlers-Danlos. Symptoms caused by atraumatic hip instability often have an insidious onset. Patients may have a wide array of hip symptoms while demonstrating only subtle findings suggestive of capsular laxity. Traction views of the affected hip can be helpful in diagnosing hip instability. Open and arthroscopic techniques can be used to treat capsular laxity. We describe an arthroscopic anterior hip capsular plication using a suture technique. PMID:20473129

  20. Is increased modularity associated with increased fretting and corrosion damage in metal-on-metal total hip arthroplasty devices?: a retrieval study.

    PubMed

    Higgs, Genymphas B; Hanzlik, Josa A; MacDonald, Daniel W; Gilbert, Jeremy L; Rimnac, Clare M; Kurtz, Steven M

    2013-09-01

    This retrieval study documents taper damage at modular interfaces in retrieved MOM THA systems and investigates if increased modularity is associated with increased fretting and corrosion. One hundred thirty-four (134) heads and 60 stems (41 modular necks) of 8 different bearing designs (5 manufacturers) were analyzed. Damage at the shell-liner interface of 18 modular CoCr acetabular liners and the corresponding 11 acetabular shells was also evaluated. The results of this study support the hypothesis that fretting and corrosion damage occurs at a variety of modular component interfaces in contemporary MOM THAs. We also found that modularity of the femoral stem was associated with increased damage at the head. An analysis of component and patient variables revealed that dissimilar alloy pairing, larger head sizes, increased medio-lateral offsets and longer neck moment arms were all associated with increased taper damage at the modular interfaces.

  1. Granular convection and its application to asteroidal resurfacing timescale

    NASA Astrophysics Data System (ADS)

    Yamada, Tomoya; Ando, Kosuke; Morota, Tomokatsu; Katsuragi, Hiroaki

    2016-04-01

    A model for the asteroid resurfacing resulting from regolith convection is built to estimate its timescale. The regolith convection by impact-induced global seismic shaking could be a possible reason for regolith migration and resultant segregated terrain which were found on the asteroids Itokawa [1]. Some recent studies [2, 3] experimentally investigated the convective velocity of the vibrated granular bed to discuss the feasibility of regolith convection under the microgravity condition such as small asteroids. These studies found that the granular convective velocity is almost proportional to the gravitational acceleration [2, 3]. Namely, the granular (regolith) convective velocity would be very low under the microgravity condition. Therefore, the timescale of resurfacing by regolith convection would become very long. In order to examine the feasibility of the resurfacing by regolith convection on asteroids, its timescale have to be compared with the surface age or the lifetime of asteroids. In this study, we aim at developing a model of asteroid resurfacing process induced by regolith convection. The model allows us to estimate the resurfacing timescale for various-sized asteroids covered with regolith. In the model, regolith convection is driven by the impact-induced global seismic shaking. The model consists of three phases, (i) Impact phase: An impactor intermittently collides with a target asteroid [4], (ii) Vibration phase: The collision results in a global seismic shaking [5], (iii) Convection phase: The global seismic shaking induces the regolith convection on the asteroid [3]. For the feasibility assessment of the resurfacing process driven by regolith convection, we estimate the regolith-convection-based resurfacing timescale T as a function of the size of a target asteroid Da. According to the estimated result, the resurfacing time scale is 40 Myr for the Itokawa-sized asteroid, and this value is shorter than the mean collisional lifetime of Itokawa

  2. Fire hazards and CO2 laser resurfacing.

    PubMed

    Wald, D; Michelow, B J; Guyuron, B; Gibb, A A

    1998-01-01

    The purpose of this study was to investigate the fire risk of laser resurfacing in the presence of supplemental oxygen. This study aims at defining safety parameters of variables such as laser energy level, oxygen flow rate, and "oxygen to laser target distance" when oxygen is delivered through a nasal cannula or nasopharyngeal tube. The typical operating room environment was simulated in the laboratory using the Yucatan minipig animal model. The energy source was a Coherent Ultrapulse CO2 laser. It was found that combustion did not occur at laser settings of 500 mJ, 50 W, 100 kHz, and a density of 5, used in conjunction with an oxygen flow rate of 6 liter/minute with the target area as close as 0.5 cm to the oxygen delivery. A total of 400 computer pattern generator treatments were delivered using this energy setting without observation of any combustion (p < 0.001). This provides evidence that while using even somewhat high laser settings and oxygen flow rate, laser induced fires can be avoided. We conclude that use of the laser in the presence of oxygen is safe, provided the target area is free of combustible fuels. Despite this assurance, laser mishaps are serious because they lead to both morbidity and mortality. It is our recommendation that close attention be constantly paid to all details, thus reducing the hazard potential of laser energy on local factors in an oxygen-rich environment. PMID:9427936

  3. Carbon dioxide laser resurfacing with fast recovery.

    PubMed

    Chajchir, Abel; Benzaquen, Iliana

    2005-01-01

    ABTRACT: Long sun exposure, in addition to ozone layer damage, produces structural damase to the normal skin. Injury to the dermal collagen and elastic fiber results in facial wrinkles. Photodamage to the skin is one of the most common sources of concern for patients visiting the plastic surgeon or dermatologist. Over the years, many alternative solutions have been developed. CO2 laser treatment is one of the alternatives bringing unique benefits and satisfactory results for both patient and surgeons. However, the initial problems of emotional discomfort, prolonged postoperative recovery and delayed return to normal activities have made patients reluctant to accept this method. This article discusses single-pass CO2 laser resurfacing with lower energy. Also, it proposes a technique that does not use wet gauze to remove the surface of the skin. This technique is applied in combination with an intensive skin care treatment. Different authors propose a single pass of CO2 laser with excellent results. With the reported method, identical long-lasting benefits are achieved, but the post-operative time is shorter.

  4. Hip Replacement

    MedlinePlus

    ... replacement is an operation in which a damaged hip joint is removed and replaced with an artificial joint. ... are many medical conditions that can damage the hip joint. (Watch the video to learn about what goes ...

  5. Hip Problems

    MedlinePlus

    ... HIPS. See your doctor. Use ice and an anti-inflammatory medicine to relieve the pain. *3. Do you ... hip pain may be from ARTHRITIS. Try an anti-inflammatory medicine. If you don't feel better, see ...

  6. Rose Hip

    MedlinePlus

    ... with your health provider.AspirinThe body breaks down aspirin to get rid of it. Rose hip contains ... of vitamin C might decrease the breakdown of aspirin. Taking large amount of rose hip along with ...

  7. Inflammatory pseudotumor of the hip: a complication of arthroplasty to be recognized by the radiologist*

    PubMed Central

    Boas, Raquel de Melo Santos Vilas; Madeira, Ivana Andrade; Lopes, Alexia Abuhid; Paiva, Edson Barreto; Rodrigues, André Soares

    2015-01-01

    Soft tissue complications following hip arthroplasty may occur either in cases of total hip arthroplasty or in hip resurfacing, a technique that has become popular in cases involving young patients. Both orthopedic and radiological literatures are now calling attention to these symptomatic periprosthetic soft tissue masses called inflammatory pseudotumors or aseptic lymphocytic vasculites-associated lesions. Pseudotumors are associated with pain, instability, neuropathy, and premature loosening of prosthetic components, frequently requiring early and difficult reoperation. Magnetic resonance imaging plays a relevant role in the evaluation of soft tissue changes in the painful hip after arthroplasty, ranging from early periprosthetic fluid collections to necrosis and more extensive tissue damage. PMID:26543283

  8. The Symmetry of Adverse Local Tissue Reactions in Patients with Bilateral Simultaneous and Sequential ASR Hip Replacement.

    PubMed

    Madanat, Rami; Hussey, Daniel K; Donahue, Gabrielle S; Potter, Hollis G; Wallace, Robert; Bragdon, Charles R; Muratoglu, Orhun K; Malchau, Henrik

    2015-10-01

    The purpose of this study was to evaluate whether patients with bilateral metal-on-metal (MoM) hip replacements have symmetric adverse local tissue reactions (ALTRs) at follow-up. An MRI of both hips was performed at a mean time of six years after surgery in 43 patients. The prevalence and severity of ALTRs were found to be similar in simultaneous hips but differences were observed in sequential hips. The order and timing of sequential hip arthroplasties did not affect the severity of ALTRs. Thus, in addition to metal ion exposure from an earlier MoM implant other factors may also play a role in the progression of ALTRs. Bilateral implants should be given special consideration in risk stratification algorithms for management of patients with MoM hip arthroplasty. PMID:26055146

  9. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  10. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  11. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  12. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  13. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  14. Formation of a pseudotumor in total hip arthroplasty using a tribological metal-polyethylene pair.

    PubMed

    Fagotti, Lorenzo; Vicente, José Ricardo Negreiros; Miyahara, Helder Souza; de Oliveira, Pedro Vitoriano; Bernabé, Antônio Carlos; Croci, Alberto Tesconi

    2015-01-01

    The aim here was to report a case of a young adult patient who evolved with tumor formation in the left thigh, 14 years after revision surgery on hip arthroplasty. Davies in 2005 made the first description of this disease in patients undergoing metal-on-metal hip arthroplasty. Over the last decade, however, pseudotumors around metal-on-polyethylene surfaces have become more prevalent. Our patient presented with increased volume of the left thigh 8 years after hip arthroplasty revision surgery. Two years before the arising of the tumor in the thigh, a nodule in the inguinal region was investigated to rule out a malignant neoplastic process, but the results were inconclusive. The main preoperative complaints were pain, functional limitation and marked reduction in the range of motion of the left hip. Plain radiographs showed loosening of acetabular and femoral, and a large mass between the muscle planes was revealed through magnetic resonance imaging of the left thigh. The surgical procedure consisted of resection of the lesion and removal of the components through lateral approach. In respect of total hip arthroplasty, pseudotumors are benign neoplasms in which the bearing surface consists of metal-on-metal, but they can also occur in different tribological pairs, as presented in this case.

  15. Formation of a pseudotumor in total hip arthroplasty using a tribological metal–polyethylene pair☆

    PubMed Central

    Fagotti, Lorenzo; Vicente, José Ricardo Negreiros; Miyahara, Helder Souza; de Oliveira, Pedro Vitoriano; Bernabé, Antônio Carlos; Croci, Alberto Tesconi

    2015-01-01

    The aim here was to report a case of a young adult patient who evolved with tumor formation in the left thigh, 14 years after revision surgery on hip arthroplasty. Davies in 2005 made the first description of this disease in patients undergoing metal-on-metal hip arthroplasty. Over the last decade, however, pseudotumors around metal-on-polyethylene surfaces have become more prevalent. Our patient presented with increased volume of the left thigh 8 years after hip arthroplasty revision surgery. Two years before the arising of the tumor in the thigh, a nodule in the inguinal region was investigated to rule out a malignant neoplastic process, but the results were inconclusive. The main preoperative complaints were pain, functional limitation and marked reduction in the range of motion of the left hip. Plain radiographs showed loosening of acetabular and femoral, and a large mass between the muscle planes was revealed through magnetic resonance imaging of the left thigh. The surgical procedure consisted of resection of the lesion and removal of the components through lateral approach. In respect of total hip arthroplasty, pseudotumors are benign neoplasms in which the bearing surface consists of metal-on-metal, but they can also occur in different tribological pairs, as presented in this case. PMID:27218090

  16. Hip arthroscopy.

    PubMed

    de Amorim Cabrita, Henrique Antônio Berwanger; de Castro Trindade, Christiano Augusto; de Campos Gurgel, Henrique Melo; Leal, Rafael Demura; de Souza Marques, Ricardo da Fonseca

    2015-01-01

    Hip arthroscopy is a safe method for treating a variety of pathological conditions that were unknown until a decade ago. Femoroacetabular impingement is the commonest of these pathological conditions and the one with the best results when treated early on. The instruments and surgical technique for hip arthroscopy continue to evolve. New indications for hip arthroscopy has been studied as the ligamentum teres injuries, capsular repair in instabilities, dissection of the sciatic nerve and repair of gluteal muscles tears (injuries to the hip rotator cuff), although still with debatable reproducibility. The complication rate is low, and ever-better results with fewer complications should be expected with the progression of the learning curve.

  17. The resurfacing history of Venus: Constraints from buffered crater densities

    NASA Astrophysics Data System (ADS)

    Kreslavsky, Mikhail A.; Ivanov, Mikhail A.; Head, James W.

    2015-04-01

    Because of atmospheric shielding and endogenic resurfacing, the population of impact craters on Venus is small (about a thousand) and consists of large craters. This population has been used in numerous studies with the goal of deciphering the geologic and geodynamic history of Venus, but the nearly spatially random nature of the crater population has complicated efforts to understand this history. Here we utilize the recent 1:15 M-scale global geological map of Venus (Ivanov, M.A., Head, J.W. [2011]. Planet. Space Sci. 59, 1559-1600) to help address this problem. The global geological map provides a stratigraphic sequence of units, and known areas where each unit is exposed on the planet. For each crater on Venus we identify the specific geological units predating and postdating the crater. We perform a statistical analysis of this set of observations with a buffered crater density approach, which rigorously and consistently takes into account the large size of craters and the fact that many craters are known to predate and/or postdate more than one unit. In this analysis we consider crater emplacement as random and resurfacing history as determined (although unknown). We obtain formal confidence intervals for the mean ages of geological units and the mean age differences between the pairs of units at the unit boundaries. We find that (1) size-frequency distributions of craters superposed on each unit are consistent with each other; (2) regional plains and stratigraphically older units have similar crater retention ages; (3) stratigraphically younger units have a mean crater retention age significantly younger than the regional plains. These findings are readily and consistently explained by global resurfacing scenarios and are difficult to reconcile with equilibrium resurfacing scenarios. Our analysis also shows that the latest recorded part of intensive resurfacing period lasted on the order of 10% of the mean surface age (tens of millions of years). The

  18. Failure of total knee arthroplasty with or without patella resurfacing

    PubMed Central

    2011-01-01

    Background and purpose Patella resurfacing during primary total knee arthroplasty (TKA) is disputed and new prosthesis designs have been introduced without documentation of their survival. We assessed the impact on prosthesis survival of patella resurfacing and of prosthesis brand, based on data from the Norwegian Arthroplasty Register. Patients and methods 5 prosthesis brands in common use with and without patella resurfacing from 1994 through 2009 were included n = 11,887. The median follow-up times were 9 years for patella-resurfaced implants and 7 years for implants without patella resurfacing. For comparison of prosthesis brands, also brands in common use with only one of the two treatment options were included in the study population (n = 25,590). Cox regression analyses were performed with different reasons for revision as endpoints with adjustment for potential confounders. Results We observed a reduced overall risk of revision for patella resurfaced (PR) TKAs, but the statistical significance was borderline (RR = 0.84, p = 0.05). At 15 years, 92% of PR and 91% of patella non resurfaced (NR) prostheses were still unrevised. However, PR implants had a lower risk of revision due to pain alone (RR = 0.1, p < 0.001), but a higher risk of revision due to loosening of the tibial component (RR = 1.4, p = 0.03) and due to a defective polyethylene insert (RR = 3.2, p < 0.001). At 10 years, the survival for the reference NR brand AGC Universal was 93%. The NR brands Genesis I, Duracon, and Tricon (RR = 1.4–1.7) performed statistically significantly worse than NR AGC Universal, while the NR prostheses e.motion, Profix, and AGC Anatomic (RR = 0.1–0.7), and the PR prostheses NexGen and AGC Universal (RR = 0.4–0.5) performed statistically significantly better. LCS, NexGen, LCS Complete (all NR), and Tricon, Genesis I, LCS, and Kinemax (all PR) showed no differences in this respect from the reference brand. A lower risk of revision (crude) was found for TKAs

  19. Comparison of friction and lubrication of different hip prostheses.

    PubMed

    Scholes, S C; Unsworth, A

    2000-01-01

    It is well documented that an important cause of osteolysis and subsequent loosening of replacement hip joints is polyethylene wear debris. To avoid this, interest has been renewed in metal-on-metal and ceramic-on-ceramic prostheses. Various workers have assessed the lubrication modes of different joints by measuring the friction at the bearing surfaces, using different lubricants. Measurements of friction factors of a series of hip prostheses were undertaken using carboxymethyl cellulose (CMC) fluids, silicone fluids, synovial fluid and different concentrations of bovine serum as the lubricant. The experimental results were compared with theoretical predictions of film thicknesses and lubrication modes. A strong correlation was observed between experiment and theory when employing CMC fluids or silicone fluids as the lubricant. Mixed lubrication was found to occur in the metal-on-metal (CoCrMo/CoCrMo) joints with all lubricants at a viscosity within the physiological range. This was also the case for the metal-on-plastic (CoCrMo/ultra-high molecular weight polyethylene) joints. The ceramic-on-ceramic (Al2O3/Al2O3) joints, however, exhibited full fluid film lubrication with the synthetic lubricants but mixed lubrication with the biological lubricants. Employing a biological fluid as the lubricant affected the friction to varying degrees when compared with the synthetic lubricants. In the case of the ceramic-on-ceramic joints it acted to increase the friction factor tenfold; however, for the metal-on-metal joints, biological fluids gave slightly lower friction than the synthetic lubricants did. This suggests that, when measuring friction and wear of artificial joints, a standard lubricant should be used.

  20. Similar patient-reported outcomes and performance after total knee arthroplasty with or without patellar resurfacing

    PubMed Central

    Ali, Abdulemir; Lindstrand, Anders; Nilsdotter, Anna; Sundberg, Martin

    2016-01-01

    Background and purpose Knee pain after total knee arthroplasty (TKA) is not uncommon. Patellar retention in TKA is one cause of postoperative knee pain, and may lead to secondary addition of a patellar component. Patellar resurfacing in TKA is controversial. Its use ranges from 2% to 90% worldwide. In this randomized study, we compared the outcome after patellar resurfacing and after no resurfacing. Patients and methods We performed a prospective, randomized study of 74 patients with primary osteoarthritis who underwent a Triathlon CR TKA. The patients were randomized to either patellar resurfacing or no resurfacing. They filled out the VAS pain score and KOOS questionnaires preoperatively, and VAS pain, KOOS, and patient satisfaction 3, 12, and 72 months postoperatively. Physical performance tests were performed preoperatively and 3 months postoperatively. Results We found similar scores for VAS pain, patient satisfaction, and KOOS 5 subscales at 3, 12, and 72 months postoperatively in the 2 groups. Physical performance tests 3 months postoperatively were also similar in the 2 groups. No secondary resurfacing was performed in the group with no resurfacing during the first 72 months Interpretation Patellar resurfacing in primary Triathlon CR TKA is of no advantage regarding pain, physical performance, KOOS 5 subscales, or patient satisfaction compared to no resurfacing. None of the patients were reoperated with secondary addition of a patellar component within 6 years. According to these results, routine patellar resurfacing in primary Triathlon TKA appears to be unnecessary. PMID:27212102

  1. Laserpeel: a peeling concept revolution with laser resurfacing protocols

    NASA Astrophysics Data System (ADS)

    Tenenbaum, Alain

    2000-06-01

    The author who is inventor of EasyPeel then Laserpeel wants to introduce new ways to choose the right indications for patients asking for cosmetic surgery. A lifting is as if you take a shirt and want to reduce its size cutting it. A resurfacing is as if you put a shirt and want to iron it. A peeling was as if you changed the color and grain of the shirt. Laserpeel is as if you iron the shirt treated with amidon, transform the second hand shirt as new, up to date on with glance effect sand give it then a stretching disco new wave effect. So, indications of facial lifting decrease at the same speed at the increase of indications of 'LASERPEEL'. Laser CO2 resurfacing should reborn because the post redness appearance decreases in intensity and duration due to LASERPEEL. LASERPEEL should be considered too as a preventive therapy coupled with preventive treatment resulting from longevity tests.

  2. Resurfacing Damaged Articular Cartilage to Restore Compressive Properties

    PubMed Central

    Grenier, Stephanie; Donnelly, Patrick E.; Gittens, Jamila; Torzilli, Peter A.

    2014-01-01

    Surface damage to articular cartilage is recognized as the initial underlying process causing the loss of mechanical function in early-stage osteoarthritis. In this study, we developed structure-modifying treatments to potentially prevent, stabilize or reverse the loss in mechanical function. Various polymers (chondroitin sulfate, carboxymethylcellulose, sodium hyaluronate) and photoinitiators (riboflavin, irgacure 2959) were applied to the surface of collagenase-degraded cartilage and crosslinked in situ using UV light irradiation. While matrix permeability and deformation significantly increased following collagenase-induced degradation of the superficial zone, resurfacing using tyramine-substituted sodium hyaluronate and riboflavin decreased both values to a level comparable to that of intact cartilage. Repetitive loading of resurfaced cartilage showed minimal variation in the mechanical response over a 7 day period. Cartilage resurfaced using a low concentration of riboflavin had viable cells in all zones while a higher concentration resulted in a thin layer of cell death in the uppermost superficial zone. Our approach to repair surface damage initiates a new therapeutic advance in the treatment of injured articular cartilage with potential benefits that include enhanced mechanical properties, reduced susceptibility to enzymatic degradation and reduced adhesion of macrophages. PMID:25468298

  3. Early PROMs following total knee arthroplasty--functional outcome dependent on patella resurfacing.

    PubMed

    Baker, Paul N; Petheram, Timothy; Dowen, Daniel; Jameson, Simon S; Avery, Peter J; Reed, Mike R; Deehan, David J

    2014-02-01

    Patella resurfacing during primary total knee arthroplasty (TKA) remains controversial. Variation in published results for patella resurfacing may potentially be explained by differences in design between TKA brands. We interrogated NJR-PROMs data to ascertain whether there is an early functional benefit to resurfacing the patella, both overall and for each of the five most popular primary knee designs through use of the Oxford Knee Score. A total of 8103 resurfaced TKAs and 15,290 nonresurfaced TKAs were studied. There was a large variation in the proportion of knees undergoing patella resurfacing by brand (Nexgen=16% versus Triathlon=52%). Patellar resurfacing did not significantly influence the magnitude of improvement in overall knee function or anterior knee-specific function irrespective of TKA brand or for cruciate retaining versus sacrificing designs.

  4. Monte Carlo computer simulations of Venus equilibrium and global resurfacing models

    NASA Technical Reports Server (NTRS)

    Dawson, D. D.; Strom, R. G.; Schaber, G. G.

    1992-01-01

    Two models have been proposed for the resurfacing history of Venus: (1) equilibrium resurfacing and (2) global resurfacing. The equilibrium model consists of two cases: in case 1, areas less than or equal to 0.03 percent of the planet are spatially randomly resurfaced at intervals of less than or greater than 150,000 yr to produce the observed spatially random distribution of impact craters and average surface age of about 500 m.y.; and in case 2, areas greater than or equal to 10 percent of the planet are resurfaced at intervals of greater than or equal to 50 m.y. The global resurfacing model proposes that the entire planet was resurfaced about 500 m.y. ago, destroying the preexisting crater population and followed by significantly reduced volcanism and tectonism. The present crater population has accumulated since then with only 4 percent of the observed craters having been embayed by more recent lavas. To test the equilibrium resurfacing model we have run several Monte Carlo computer simulations for the two proposed cases. It is shown that the equilibrium resurfacing model is not a valid model for an explanation of the observed crater population characteristics or Venus' resurfacing history. The global resurfacing model is the most likely explanation for the characteristics of Venus' cratering record. The amount of resurfacing since that event, some 500 m.y. ago, can be estimated by a different type of Monte Carolo simulation. To date, our initial simulation has only considered the easiest case to implement. In this case, the volcanic events are randomly distributed across the entire planet and, therefore, contrary to observation, the flooded craters are also randomly distributed across the planet.

  5. Hip Implant Systems

    MedlinePlus

    ... hip replacement surgery, the damaged portions of the hip joint are removed. The ball (femoral head) is removed ... hip or leg Swelling at or near the hip joint A limp or change in walking ability Noise ( ...

  6. A frictional study of total hip joint replacements

    NASA Astrophysics Data System (ADS)

    Scholes, S. C.; Unsworth, A.; Goldsmith, A. A. J.

    2000-12-01

    Polymeric wear debris produced by articulation of the femoral head against the ultra-high-molecular-weight polyethylene socket of a total hip replacement has been implicated as the main cause of osteolysis and subsequent failure of these implants. Potential solutions to this problem are to employ hard bearing surface combinations such as metal-on-metal or ceramic-on-ceramic prostheses. The aim of this study was to investigate the difference in lubrication modes and friction of a range of material combinations using synthetic and biological fluids as the lubricants. The experimental results were compared with theoretical predictions of film thicknesses and lubrication modes. A strong correlation was observed between experiment and theory when employing carboxy methyl cellulose (CMC) fluids as the lubricant. Under these conditions the ceramic-on-ceramic joints showed full fluid film lubrication while the metal-on-metal, metal-on-plastic, diamond-like carbon-coated stainless steel (DLC)-on-plastic and ceramic-on-plastic prostheses operated under a mixed lubrication regime. With bovine serum as the lubricant in the all ceramic joints, however, the full fluid film lubrication was inhibited due to adsorbed proteins. In the metal-on-metal joints this adsorbed protein layer acted to reduce the friction while in the ceramic coupling the friction was increased. The use of bovine serum as the lubricant also significantly increased the friction in both the metal-on-plastic and ceramic-on-plastic joints. The friction produced by the DLC-on-plastic joints depended on the quality of the coating. Those joints with a less consistent coating and therefore a higher surface roughness gave significantly higher friction than the smoother, more consistently coated heads.

  7. Recontouring, resurfacing, and scar revision in skin cancer reconstruction.

    PubMed

    Brenner, Michael J; Perro, Christopher A

    2009-08-01

    Residual disfigurement is a common problem for patients who have undergone skin cancer reconstruction. Restoring form and function in these patients is an artistic and technical endeavor. The efficacy of surgical scar revision, dermabrasion, chemical peels, and laser resurfacing is predicated upon the skin's innate ability to regenerate over time in response to mechanical, chemical, and thermal or ablative stresses. The patient and surgeon should be accepting of a process that is often gradual and may proceed in stages. Achieving proficiency with the secondary procedures for improving scars and local flaps may allow the motivated surgeon to mold an initially passable surgical result into an excellent one.

  8. 3D Spherical Convection Modeling of Venusian Resurfacing Mechanisms

    NASA Astrophysics Data System (ADS)

    Prunty, A. C.; King, S. D.

    2014-12-01

    The surface of Venus is thought to have undergone a global resurfacing event approximately 750 Ma. While several variations and modifications within the proposed resurfacing models exist, two end-member mechanisms can be broadly identified: (1) catastrophic overturns of the lithosphere, and (2) global volcanic resurfacing. We perform high-resolution, 3D spherical convection calculations using CitcomS to determine the conditions in Venus' deep interior necessary for each mechanism to occur. To date, we have focused on modeling episodic overturns of the lithosphere in the stagnant lid regime following the method of van Heck and Tackley (2008), and implementing a temperature-dependent rheology and yield stress. We find in general that lithospheric yielding can occur with a Rayleigh number of the order of 105 and a yield stress of the order of 20 ­- 400 MPa, consistent with the results of van Heck and Tackley. Additionally, we find that the behavior of lithospheric overturn depends strongly on the yield stress. To see this, we systematically increase the Rayleigh number and the yield stress via a priori scaling relationships. We find that models with Rayleigh number between 105 and 108 exhibit some variation of stagnant-lid convection; however, we observe that by varying the yield stress we are able to control the degree to which the overturns consist of the subduction of large, coherent segments of lithosphere as opposed to the formation of a large number of smaller, regional delaminations. We analyze these two modes of overturn by looking at the resultant geoid and topography fields to see if they yield distinguishable signatures. Furthermore, we analyze the spherical harmonic power spectrum of the geoid and topography to determine the extent to which their signatures are contributed from lower mantle anomalies and surface features. We also test the effects of mineral phase transformations and depth­-increasing viscosity on lithospheric overturn behavior by varying

  9. Recontouring, resurfacing, and scar revision in skin cancer reconstruction.

    PubMed

    Brenner, Michael J; Perro, Christopher A

    2009-08-01

    Residual disfigurement is a common problem for patients who have undergone skin cancer reconstruction. Restoring form and function in these patients is an artistic and technical endeavor. The efficacy of surgical scar revision, dermabrasion, chemical peels, and laser resurfacing is predicated upon the skin's innate ability to regenerate over time in response to mechanical, chemical, and thermal or ablative stresses. The patient and surgeon should be accepting of a process that is often gradual and may proceed in stages. Achieving proficiency with the secondary procedures for improving scars and local flaps may allow the motivated surgeon to mold an initially passable surgical result into an excellent one. PMID:19698924

  10. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  11. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  12. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  13. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  14. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  15. Thermal measurements of short-duration CO2 laser resurfacing

    NASA Astrophysics Data System (ADS)

    Harris, David M.; Fried, Daniel; Reinisch, Lou; Bell, Thomas; Lyver, Rex

    1997-05-01

    The thermal consequences of a 100 microsecond carbon-dioxide laser used for skin resurfacing were examined with infrared radiometry. Human skin was evaluated in a cosmetic surgery clinic and extirpated rodent skin was measured in a research laboratory. Thermal relaxation following single pulses of in vivo human and ex vivo animal skin were quantitatively similar in the 30 - 1000 msec range. The thermal emission from the area of the irradiated tissue increased monotonically with increasing incident laser fluence. Extremely high peak temperatures during the 100 microsecond pulse are attributed to plume incandescence. Ejecta thermal emission may also contribute to our measurements during the first several msecs. The data are combined into a thermal relaxation model. Given known coefficients, and adjusting tissue absorption to reflect a 50% water content, and thermal conductivity of 2.3 times that of water, the measured (both animal back and human forearm) and calculated values coincide. The high thermal conductance suggests preferential thermal conduction along the protein matrix. The clinical observation of a resurfacing procedure clearly shows thermal overlap and build-up is a result of sequential, adjacent pulses. A decrease of 4 - 6 degrees Celsius in surface temperature at the treatment site that appeared immediately post-Tx and gradually diminished over several days is possibly a sign of dermal convective and/or evaporative cooling.

  16. Does patella resurfacing really matter? Pain and function in 972 patients after primary total knee arthroplasty

    PubMed Central

    Espehaug, Birgitte; Havelin, Leif Ivar; Vollset, Stein Emil; Furnes, Ove

    2010-01-01

    Background and purpose Resurfacing of the patella during primary total knee arthroplasty (TKA) is often recommended based on higher revision rates in non-resurfaced knees. As many of these revisions are insertions of a patella component due to pain, and since only patients with a non-resurfaced patella have the option of secondary resurfacing, we do not really know whether these patients have more pain and poorer function. The main purpose of the present paper was therefore to assess pain and function at least 2 years after surgery for unrevised primary non-resurfaced and resurfaced TKA, and secondary among prosthesis brands. Methods Information needed to calculate subscales from the knee injury and osteoarthritis outcome score (KOOS) was collected in a questionnaire given to 972 osteoarthritis patients with intact primary TKAs that had been reported to the Norwegian Arthroplasty Register. Pain and satisfaction on visual analog scales and improvement in EQ-5D index score ΔEQ-5D) were also used as outcomes. Outcomes were measured on a scale from 0 to 100 units (worst to best). To estimate differences in mean scores, we used multiple linear regression with adjustment for possible confounders. Results We did not observe any differences between resurfacing and non-resurfacing in any outcome, with estimated differences of ≤ 1.4 units and p-values of > 0.4. There was, however, a tendency of better results for the NexGen implant as compared to the reference brand AGC for symptoms (difference = 4.9, p = 0.05), pain (VAS) (difference = 8.3, p = 0.004), and satisfaction (VAS) (difference = 7.9, p = 0.02). However, none of these differences reached the stated level of minimal perceptible clinical difference. Interpretation Resurfacing of the patella has no clinical effect on pain and function after TKA. Differences between the brands investigated were small and they were assumed to be of minor importance. PMID:20158405

  17. Group C streptococcal septic arthritis of a prosthetic hip joint following dental treatment.

    PubMed

    Al-Himdani, Sarah; Woodnutt, David

    2015-10-22

    We report a case of a prosthetic joint infection occurring secondary to group C Streptococcus following dental treatment in a 66-year-old woman. This patient presented 11 years following a right hip resurfacing procedure with increasing pain and difficulty mobilising the right hip. An ultrasound and MRI scan identified a collection in the right hip joint, which was subsequently aspirated. Cultures revealed a group C Streptococcus. Extensive washout and surgical debridement of the hip joint was undertaken and the patient was treated with a protracted course of antibiotics. At 1 year follow-up, the patient demonstrated no evidence of recurrent infection. We discuss the evidence underlying prophylactic antibiotic usage regarding dental procedures in the prevention of septic arthritis in patients with prosthetic joints. We also review the spectrum of diseases caused by this organism.

  18. Distal Radius Isoelastic Resurfacing Prosthesis: A Preliminary Report

    PubMed Central

    Ichihara, Satoshi; Díaz, Juan José Hidalgo; Peterson, Brett; Facca, Sybille; Bodin, Frédéric; Liverneaux, Philippe

    2015-01-01

    Background Here we present a preliminary case series of unicompartmental isoelastic resurfacing prosthesis of the distal radius to treat comminuted articular fractures of osteoporotic elderly patients. Materials and Methods Our study included 12 patients, mean age 76 years, who presented with comminuted osteoporotic distal radius fracture. Because of the severity of injury and poor bone quality; osteosynthesis was not deemed to be a good option. Description of Technique The surgery was performed through a dorsal approach. The subchondral bone of the entire distal radial articular was excised and a unicompartmental prosthesis was applied. Results At an average follow-up of 32 months, the pain was 2.8/10, Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) 37.4/100, grip strength in neutral 49.9%, in supination 59.0%, and in pronation 56.2% of the contralateral normal side. The wrist ranges of motion in flexion and extension were 56.1% and 79.3%, in supination and pronation 87.7% and 91.0% of the contralateral normal side. Two patients experienced a complex regional pain syndrome (CRPS) type II; these resolved spontaneously. One patient experienced distal radioulnar joint (DRUJ) stiffness, which improved after an ulna head resection. Finally, one patient required revision surgery after a secondary traumatic fracture. Radiographically; the average volar tilt was 9.8°; the average of radial inclination was 11.6°. Conclusion The concept of a unicompartmental isoelastic resurfacing prosthesis offers a promising option for the treatment of comminuted, osteoporotic distal radius articular fractures of elderly patients. Level of Evidence IV PMID:26261738

  19. [Metal/metal--a new (old) hip bearing system in clinical evaluation. Prospective 7-year follow-up study].

    PubMed

    Jessen, N; Nickel, A; Schikora, K; Büttner-Janz, K

    2004-05-01

    The problems of wear debris of bearing systems containing polyethylene used in hip arthroplasty have led to an increased trend to hard on hard bearing surfaces. Based on our own good experiences with the cementless Zweymüller-Alloclassic system, we implanted the same system with metal-on-metal bearing surfaces (Metasul) in 100 cases between October 1993 and November 1994. In order to record potential side effects, specific questioning and a clinical and radiological survey were carried out before surgery and in regular intervals thereafter. Up to date almost all of the patients have had good and excellent results with an average of more than 90 points in the Harris hip score (47.8 before surgery). There were no cases of revision surgery as a result of aseptic loosening. Two revisions were performed for other reasons (change of the insert, deep infection). No disadvantageous phenomena related to Metasul in the surrounding tissue were found on macroscopic and histologic investigation. The radiological examination did not show any specific signs pertaining to the use of a metal-on-metal bearing system. We also have no grounds to suppose that there are systemic reactions due to chromium or cobalt ions. Up to now, the new metal-on-metal bearing system in connection with a proven hip arthroplasty system has lived up to clinical expectations. With regard to less wear debris, it is justified to implant it in younger patients as well. Other open questions, in particular the possibly improved long-term results, have to be answered by continuation of the study. PMID:15118821

  20. Serum Metal Ions with a Titanium Modular Neck Total Hip Replacement System.

    PubMed

    Gofton, Wade; Beaule, Paul E

    2015-10-01

    The goal of this study is to evaluate serum levels of chromium (Cr), cobalt (Co), and titanium (Ti) within the first two years following total hip arthroplasty using a Ti modular neck system. Twenty-five patients were randomized to a metal-on-metal (MoM) bearing with an all CoCr shell, and the remaining 25 received a metal-on-polyethylene (MoP) with a Ti shell. Serum levels demonstrated increases for Cr, Co, and Ti at 1 year (P < .001). MoM had similar Ti levels to MoP hips at 1 year (P=0.11) but lower at 2 years (P=0.03). Results suggest that the passive corrosion (i.e., chemical, pitting, and crevice corrosion) of exposed non-articular metal surfaces may be a greater source of ions than the neck-stem or head-neck interfaces.

  1. Timescale of asteroid resurfacing by regolith convection resulting from the impact-induced global seismic shaking

    NASA Astrophysics Data System (ADS)

    Yamada, Tomoya M.; Ando, Kousuke; Morota, Tomokatsu; Katsuragi, Hiroaki

    2016-07-01

    A model for the asteroid resurfacing by regolith convection is built to estimate its timescale. In the model, regolith convection is driven by the impact-induced global seismic shaking. The model consists of three steps: (i) intermittent impact of meteoroids, (ii) impact-induced global vibration (seismic shaking), and (iii) vibration-induced regolith convection. In order to assess the feasibility of the resurfacing process driven by regolith convection, we estimate the resurfacing timescale as a function of the size of a target asteroid. In the estimate, a set of parameter values is assumed on the basis of previous works. However, some of them (e.g., seismic quality factor Q, seismic efficiency η, and seismic frequency f) are very uncertain. Although these parameter values might depend on asteroid size, we employ the standard values to estimate the representative behavior. To clarify the parameter dependences, we develop an approximated scaling form for the resurfacing timescale. According to the estimated result, we find that the regolith-convection-based resurfacing timescale is shorter than the mean collisional lifetime in most of the parameter uncertainty ranges. These parameter ranges are within those reported by previous works for small asteroids. This means that the regolith convection can be a possible mechanism for the asteroid resurfacing process.

  2. History of plains resurfacing in the Scandia region of Mars

    USGS Publications Warehouse

    Tanaka, Kenneth L.; Fortezzo, Corey M.; Hayward, Rosalyn K.; Rodriguez, J. Alexis P.; Skinner, James A.

    2011-01-01

    We present a preliminary photogeologic map of the Scandia region of Mars with the objective of reconstructing its resurfacing history. The Scandia region includes the lower section of the regional lowland slope of Vastitas Borealis extending about 500–1800 km away from Alba Mons into the Scandia sub-basin below −4800 m elevation. Twenty mapped geologic units express the diverse stratigraphy of the region. We particularly focus on the materials making up the Vastitas Borealis plains and its Scandia sub-region, where erosional processes have obscured stratigraphic relations and made the reconstruction of the resurfacing history particularly challenging. Geologic mapping implicates the deposition, erosion, and deformation/degradation of geologic units predominantly during Late Hesperian and Early Amazonian time (~3.6–3.3 Ga). During this time, Alba Mons was active, outflow channels were debouching sediments into the northern plains, and basal ice layers of the north polar plateau were accumulating. We identify zones of regional tectonic contraction and extension as well as gradation and mantling. Depressions and scarps within these zones indicate collapse and gradation of Scandia outcrops and surfaces at scales of meters to hundreds of meters. We find that Scandia Tholi display concentric ridges, rugged peaks, irregular depressions, and moats that suggest uplift and tilting of layered plains material by diapirs and extrusion, erosion, and deflation of viscous, sedimentary slurries as previously suggested. These appear to be long-lived features that both pre-date and post-date impact craters. Mesa-forming features may have similar origins and occur along the southern margin of the Scandia region, including near the Phoenix Mars Lander site. Distinctive lobate materials associated with local impact craters suggest impact-induced mobilization of surface materials. We suggest that the formation of the Scandia region features potentially resulted from crustal heating

  3. Global Resurfacing on Venus: Implications on Plume Motion and Topography

    NASA Astrophysics Data System (ADS)

    Stein, C.; Hansen, U.

    2008-09-01

    ABSTRACT A global resurfacing event is supposed to have taken place on Venus (1; 2). Today, however,Venus is a one-plate planet, i.e. the complete surface is covered by one immobile plate. Such a behaviour is also observed in numerical mantle convection models with variable viscosity. Moresi and Solomatov (3) presented a 2D study of mantle convection with a strong temperature dependence and an additional stress dependence of the viscosity. While the strong temperature dependence causes a cold, rigid and immobile surface atop the convective cycle in the planet's mantle, the additional stress dependence leads to deformation zones in the so-called stagnant lid. By using a 3D study Trompert and Hansen (4) also showed that in this way pieces of the surface are mobilised and take part in the convective cycle. The amount of surface subducted and the temporal evolution of the system depend on the strength of the stress dependence. With increasing stress dependence the surface is more strongly weakened (5) and subduction events occur more rapidly (6). Thus we find that for a low stress dependence sporadic subduction events of the complete surface interrupt otherwise stagnant lid convection. The effect of the subduction of cold, rigid material on both the plume motion and the surface topography is investigated.

  4. Developmental dysplasia of the hip

    MedlinePlus

    ... Developmental hip dysplasia; DDH; Congenital dysplasia of the hip; Congenital dislocation of the hip; CDH; Pavlik harness ... dislocation Shorter leg on the side with the hip dislocation Uneven skin folds of thigh or buttocks After ...

  5. Resurfacing shoulder arthroplasty for the treatment of severe rheumatoid arthritis

    PubMed Central

    Voorde, Pia C ten; Rasmussen, Jeppe V; Olsen, Bo S; Brorson, Stig

    2015-01-01

    Background and purpose There is no consensus on which type of shoulder prosthesis should be used in patients with rheumatoid arthritis (RA). We describe patients with RA who were treated with shoulder replacement, regarding patient-reported outcome, prosthesis survival, and causes of revision, and we compare outcome after resurfacing hemi-arthroplasty (RHA) and stemmed hemi-arthroplasty (SHA). Patients and methods We used data from the national Danish Shoulder Arthroplasty Registry and included patients with RA who underwent shoulder arthroplasty in Denmark between 2006 and 2010. Patient-reported outcome was obtained 1-year postoperatively using the Western Ontario Osteoarthritis of the Shoulder index (WOOS), and rates of revision were calculated by checking revisions reported until December 2011. The patient-reported outcome of RHA was compared to that of SHA using regression analysis with adjustment for age, sex, and previous surgery. Results During the study period, 167 patients underwent shoulder arthroplasty because of rheumatoid arthritis, 80 (48%) of whom received RHA and 34 (26%) of whom received SHA. 16 patients were treated with total stemmed shoulder arthroplasty (TSA), and 24 were treated with reverse shoulder arthroplasty (rTSA). 130 patients returned a completed questionnaire, and the total mean WOOS score was 63. The cumulative 5-year revision rate was 7%. Most revisions occurred after RHA, with a revision rate of 14%. Mean WOOS score was similar for RHA and for SHA. Interpretation This study shows that shoulder arthroplasty, regardless of design, is a good option in terms of reducing pain and improving function in RA patients. The high revision rate in the RHA group suggests that other designs may offer better implant survival. However, this should be confirmed in larger studies. PMID:25673155

  6. Hip joint replacement

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002975.htm Hip joint replacement To use the sharing features on this page, please enable JavaScript. Hip joint replacement is surgery to replace all or part ...

  7. Hip Injuries and Disorders

    MedlinePlus

    ... or falling can all sometimes lead to hip injuries. These include Strains Bursitis Dislocations Fractures Certain diseases also lead to hip injuries or problems. Osteoarthritis can cause pain and limited ...

  8. Bursitis of the Hip

    MedlinePlus

    ... following: Repeated overuse or stress of the hip Rheumatoid arthritis Gout Pseudogout Injury of the hip Infection with bacteria, such as Staphylococcus aureus (or a staph infection) Diabetes Spine problems, such as scoliosis Uneven leg lengths ...

  9. Hip replacement - discharge

    MedlinePlus

    ... or part of your hip joint with an artificial joint. This artificial joint is called a prosthesis. ... be careful that you do not dislocate your artificial hip, especially in the first few months after ...

  10. Clinical applications of CO2 laser resurfacing in the treatment of various pathologic skin disorders

    NASA Astrophysics Data System (ADS)

    Giler, Shamai

    1997-12-01

    CO2 laser skin resurfacing devices are widely used in cosmetic surgery for the treatment of facial rhytides, acne scars and aging skin. This technique is also useful in the treatment of various benign and premalignant or multiple pathological skin conditions and disorders originating in the epidermal, dermal and skin appendages, vascular lesions, epidermal nevi, infected wounds and ulcers, and keloids. Various surgical techniques have been developed in our clinic using laser resurfacing in the treatment of more than 2,000 patients with various skin pathologic disorders. We describe our experience with the various techniques used. The precise depth control and ablation properties combined with the hemostatic and sterilizing effects of the CO2 laser beam, reduction of the possibility of bleeding, infection and damage to healthy tissues, make the CO2 laser resurfacing techniques the treatment of choice for cosmetic surgery and treatment of benign, premalignant and multiple pathologic skin conditions.

  11. Subsurface damage induced in dental resurfacing of a feldspar porcelain with coarse diamond burs.

    PubMed

    Song, Xiao-Fei; Yin, Ling

    2009-02-01

    The primary cause for early failure of ceramic restorations is surface and subsurface damage induced in adjustment and resurfacing using dental handpieces/burs. This paper reports finite element analysis (FEA) modelling of dental resurfacing to predict the degrees of subsurface damage, in combination with experimental measurement using scanning electron microscopy (SEM). The FEA predictions of subsurface damage induced in a feldspar porcelain with coarse diamond burs were in agreement with the SEM experimental measurement. These findings provide dental clinicians a quantitative description of the response of dental resurfacing-induced subsurface damage. The implication of the results for non-destructive evaluation of subsurface damage by FEA modelling will be practically meaningful to clinical dental restorations for high-quality ceramic restorations. PMID:19144338

  12. Periprosthetic humeral fracture after Copeland resurfacing and the role of revision arthroplasty: A report of three cases

    PubMed Central

    MacLean, Simon Bruce Murdoch; Mangat, Karanjit; Nandra, Rajpal; Kalogrianitis, Socrates

    2015-01-01

    Follow-up series of the Copeland resurfacing hemiarthroplasty have reported few postoperative fractures around the prosthesis. We report three cases of periprosthetic fracture around a Copeland resurfacing arthroplasty. Due to prosthetic loosening and tuberosity comminution, all cases were managed with revision shoulder arthroplasty. All patients had good functional outcome and range of movement on early follow-up. PMID:26622129

  13. A painful soft tissue mass secondary to impingement of a metal on polyethylene bearing total hip arthroplasty.

    PubMed

    William, Griffiths-Jones; Daniel, Williams

    2014-05-20

    A 60-year-old woman underwent a metal on polyethylene total hip replacement. The patient experienced pain and sustained multiple dislocations over the following 2 years and was referred for consideration of revision surgery. At the time of revision surgery it was found that there was a significant amount of polyethylene wear likely to have arisen as a result of the neutral cup placement and subsequent anterior impingement. A large cystic mass was excised and on histology was found to contain tissue with a lymphocytic infiltrate with a large amount of intracellular birefringent debris, consistent with polyethylene. The appearance of such masses is well reported as pseudotumours in metal-on-metal hip replacements but as yet their aetiology is unknown. We believe that the formation of the mass in this case could represent a model by which these pseudotumours occur.

  14. Subsurface changes of a MoM hip implant below different contact zones.

    PubMed

    Pourzal, Robin; Theissmann, Ralf; Williams, Sophie; Gleising, Birgit; Fisher, John; Fischer, Alfons

    2009-04-01

    Metal-on-metal hip arthroplasties undergo distinct release of toxic metal particles and ions. Thus, it is necessary to minimize this. In order to evaluate the wear behaviour of metal-on-metal hip replacements it is essential to understand the micro-structural changes in the sub-surface region. Previous studies revealed that cobalt chromium metal-on-metal implants are able to alter their mechanical behaviour by adjusting the microstructure to load. The reason for this is the so-called mechanical mixing. This means that a nano-crystal layer is formed by rotating clusters of atoms that incorporate denatured proteins from the interfacial medium. This is followed by a layer of rhombic shaped nano-crystals in between sheared epsilon-martensite lathes, twins, and stacking faults. Although the primary wear zone has been well characterized, the sub-surface structure of the stripe wear and the non-contact zone of the hip ball have yet to be analysed. For this study a 28-mm cobalt base alloy femoral head and acetabular cup were analysed. The implant was simulator tested for 5 million cycles with the application of micro-separation resulting in a clearly visible stripe wear appearance. The TEM micrograph of the primary wear zone of the ball confirmed the presence of a sub-surface layer of nano-crystals. The thickness of this layer was approximately 200 nm and the average grain diameter ranged from 35 to 40 nm. Within the stripe wear zone the micrographs also revealed a nano-crystal layer but with a thickness of only 50 nm and an average grain diameter from 15 to 20 nm. The carbon and oxygen content was highest closest to the surface which proves the occurrence of mechanical mixing. The non-contact zone of the ball was analysed as well. When compared to the primary wear zone a nano-crystal layer with similar thickness but with an average grain diameter smaller than 15 nm was observed.

  15. Does prosthesis design affect the need for secondary resurfacing in total knee arthroplasty?

    PubMed Central

    Rotigliano, Niccolò; Hirschmann, Michael T.

    2016-01-01

    Aims and Objectives: The purpose of this retrospective consecutive study was to compare the rate of secondary resurfacing in consecutive series of five different TKA systems. It was our hypothesis that different brands of TKA show different rates of secondary resurfacing. Materials and Methods: A retrospective study was performed on data from patients who underwent TKA without primary patellar resurfacing from 2004 to 2012 in an university affiliated hospital. The study cohort included 784 patients (m:f=302:482, mean age at surgery±SD 71±10) operated with TKA during this period. Five different cruciate-retaining TKA systems were used in consecutives series. These were the following: A) Triathlon, Stryker, Switzerland (n=296), B) PFC Sigma, DepuySynthes, Switzerland (n=215), C) LCS, DepuySynthes, Switzerland (n=80), D) Balansys, Mathys, Bettlach, Switzerland (n=129), E) Duracon, Stryker, Switzerland (n=64). Data was retrospectively obtained from our different hospital archives. Patients demographics, age at surgery, type of total knee arthroplasty were noted. In addition, the data were screened for a secondary resurfacing in each patient. On anterior-posterior, lateral and skyline view radiographs different measurements were performed. TKA component position was assessed on radiographs with respect to "The knee society total knee arthroplasty roentgenographic evaluation and scoring system (TKA-RESS). Pearson Chi square test was used to compare differences between groups (p<0.05). There was no significant difference between the groups in terms of age, gender, and radiological outcomes. Results: Twenty-six of 784 patients (3.3%) underwent secondary resurfacing due to patellofemoral pain during follow-up. In group A four of 296 patients (1.4%), in group B fifteen of 215 patients (7%), in group C four of 80 patients (5%), in group D two of 129 patients (1.6%), in group E one of 64 patients (1.6%) underwent secondary patellar resurfacing during follow-up. There was a

  16. The Use of Shoulder Hemiarthroplasty and Humeral Head Resurfacing: A Review of Current Concepts

    PubMed Central

    Widnall, James C; Dheerendra, Sujay K; MacFarlane, Robert J; Waseem, Mohammad

    2013-01-01

    Since Neer’s early work in the 1950s shoulder arthroplasty has evolved as a treatment option for various glenohumeral joint disorders. Both hemiarthroplasty and total shoulder prostheses have associated problems. This has led to further work with regards to potential resurfacing, with the aim of accurately restoring native proximal humeral anatomy while preserving bone stock for later procedures if required. Hemiarthroplasty remains a valuable treatment option in the low demand patient or in the trauma setting. Additional work is required to further define the role of humeral resurfacing, with the potential for it to become the gold standard for younger patients with isolated humeral head arthritis. PMID:24082971

  17. Resurfacing events on Venus: Implications on plume dynamics and surface topography

    NASA Astrophysics Data System (ADS)

    Stein, C.; Fahl, A.; Hansen, U.

    2010-01-01

    Global resurfacing events explain the relatively young and uniformly aged surface of Venus. In numerical models featuring these events a variety of plume classes occur ranging from strong, stable to smaller, wind-driven upwellings. We investigate this plume dynamics in a 3D Cartesian geometry paying special attention to the surface topography. While the stable upwellings of the stagnant-lid phase correlate with an elevation of the surface, the wind-driven upwellings of the resurfacing phase do not necessarily correlate with a positive topography signal. We rather observe that a thick plate can dominate the topography above upwellings.

  18. High Cup Angle and Microseparation Increase the Wear of Hip Surface Replacements

    PubMed Central

    Williams, Sophie; Isaac, Graham; Ingham, Eileen; Fisher, John

    2009-01-01

    High wear rates and high patient ion levels have been associated with high (> 55°) cup inclination angles for metal-on-metal surface replacements. Wear rates and patterns have been simulated for ceramic-on-ceramic bearings by applying microseparation to replicate head offset deficiency. We tested 39-mm metal-on-metal surface replacements (n = 5) in a hip simulator with (A) an increased cup inclination angle of 60° and (B) an increased cup inclination angle and microseparation over 2 million cycles. (A) resulted in a ninefold increase in wear rate and (B) resulted in a 17-fold increase in wear rate compared to a standard gait condition study. Wear particles produced under microseparation conditions were larger than those produced under standard conditions but of similar shape (round to oval). The data suggest both head and cup position influence the wear of surface replacements; we believe it likely bearings with high wear either have a high cup inclination angle, an offset deficient head, or a combination of both. PMID:19363640

  19. Survivorship of Primary Hip Arthroscopy in New York State - A Population-Based Study

    PubMed Central

    Nawabi, Danyal H.; Degen, Ryan; Pan, Ting; Ranawat, Anil S.; Kelly, Bryan T.; Lyman, Stephen

    2016-01-01

    Objectives: Hip arthroscopy utilization has significantly increased over the past decade, with annual rates increasing as much as 300-600% in that time period. While large sample data demonstrates significant improvement in clinical outcomes out to two years post-operatively, with low rates of associated post-operative complications, there is little information on the long-term survival of primary hip arthroscopy procedures. The purpose of this study is to report on the rates of revision hip arthroscopy and conversion to resurfacing or total hip arthroplasty (THA) following hip arthroscopy in the State of New York. We will also report on prognostic variables that may contribute to the need for repeat surgery. Methods: The Statewide Planning and Research Cooperative System (SPARCS) database, a census of all hospital admissions and ambulatory surgery in New York State, was used to identify cases of outpatient primary hip arthroscopy. Demographic information was collected for these patients. After case identification, unique identifiers were utilized to identify those patients that underwent revision hip arthroscopy or subsequent ipsilateral hip resurfacing or THA. The risks of each of these outcomes were modeled with use of age, sex, socio-economic status, hospital and surgeon volume as potential risk factors. Patients were also tracked for 30-day and 90-day complications requiring re-admission. Results: We identified 8,267 hip arthroscopy cases from 1998-2012 performed by 295 surgeons in 137 different surgical centers. Demographics revealed that 46.1% of patients were male, with 80.2% carrying private insurance. Annual hip arthroscopy rates increased 88-fold over the observation period, with a 750% increase over the last 10 years. Revision surgery (scope or arthroplasty) was required in 1,087 cases (13.1%) at a mean of 622 ± 603 days. More specifically, revision hip arthroscopy was required in 310 cases (3.8%) at a mean of 649 ± 586 days after the index procedure

  20. Multi-center clinical study and review of fractional ablative CO2 laser resurfacing for the treatment of rhytides, photoaging, scars and striae.

    PubMed

    Alexiades-Armenakas, Macrene; Sarnoff, Deborah; Gotkin, Robert; Sadick, Neil

    2011-04-01

    Laser skin resurfacing has shifted over the past two decades from standard ablative resurfacing to non-ablative resurfacing and most recently, to fractional laser resurfacing. In this most recent category, fractional non-ablative lasers were first introduced followed by fractional ablative lasers, which offer an improved balance between safety and efficacy. In the current article, a review of fractional ablative resurfacing is presented alongside the results from a multi-center clinical study employing the fractional carbon dioxide (CO2) laser (SmartXide DOT, DEKA) for the treatment of rhytides, photoaging, scars and striae distensae.

  1. Early surveillance of ceramic-on-metal total hip arthroplasty.

    PubMed

    Hill, J C; Diamond, O J; O'Brien, S; Boldt, J G; Stevenson, M; Beverland, D E

    2015-03-01

    Ceramic-on-metal (CoM) is a relatively new bearing combination for total hip arthroplasty (THA) with few reported outcomes. A total of 287 CoM THAs were carried out in 271 patients (mean age 55.6 years (20 to 77), 150 THAs in female patients, 137 in male) under the care of a single surgeon between October 2007 and October 2009. With the issues surrounding metal-on-metal bearings the decision was taken to review these patients between March and November 2011, at a mean follow-up of 34 months (23 to 45) and to record pain, outcome scores, radiological analysis and blood ion levels. The mean Oxford Hip Score was 19.2 (12 to 53), 254 patients with 268 hips (95%) had mild/very mild/no pain, the mean angle of inclination of the acetabular component was 44.8(o) (28(o) to 63(o)), 82 stems (29%) had evidence of radiolucent lines of > 1 mm in at least one Gruen zone and the median levels of cobalt and chromium ions in the blood were 0.83 μg/L (0.24 μg/L to 27.56 μg/L) and 0.78 μg/L (0.21 μg/L to 8.84 μg/L), respectively. The five-year survival rate is 96.9% (95% confidence interval 94.7% to 99%). Due to the presence of radiolucent lines and the higher than expected levels of metal ions in the blood, we would not recommend the use of CoM THA without further long-term follow-up. We plan to monitor all these patients regularly. PMID:25737511

  2. An analysis of screw fixation of the femoral component in cementless hip arthroplasty.

    PubMed

    Martin, J W; Sugiyama, H; Kaiser, A D; Van Hoech, J; Whiteside, L A

    1990-01-01

    A cementless hip stem that allows screw fixation of the collar to cortical bone in the calcar region was found to achieve enhanced rotational stability when implanted in preserved cadaveric human femora. Although the implants with screws showed less tendency for subsidence than the implants without screws, rotational micromotion was not found to be statistically different under light loading conditions. When implanted in composite bone, the addition of screws in the configuration tested was associated with significant metal-on-metal wear during combined compression and rotational cyclic loading. This finding is of concern due to potential wear particle toxicity and possible lowered fatigue life of the prosthesis. Therefore, specific design changes are recommended. PMID:2243211

  3. Transient Synovitis of the Hip

    MedlinePlus

    ... inflammation and swelling of the tissues around the hip joint. Usually only one hip is affected. This condition ... to reduce the swelling and inflammation around the hip joint. Your child's doctor will probably ask you to ...

  4. Hard-on-Hard Total Hip Impingement Causes Extreme Contact Stress Concentrations

    PubMed Central

    Elkins, Jacob M.; O’Brien, Megan K.; Stroud, Nicholas J.; Pedersen, Douglas R.; Callaghan, John J.

    2010-01-01

    Background Impingement events, in addition to their role immediately proximate to frank dislocation, hold the potential to damage new-generation hard-on-hard bearings as a result of the relatively unforgiving nature of the materials and designs. Because of the higher stiffness and tighter design tolerances of metal-on-metal and ceramic implants, surgical positioning plausibly has become even more important. Questions/purposes We asked (1) whether, and under what cup orientation conditions, hard-on-hard impingements might challenge implant material failure strength; and (2) whether particle generation propensity at impingement and egress sites would show similar dependence on cup orientation. Methods Realistic computational simulations were enabled by multistage finite element analyses, addressing both global construct motion and loading, and focal stress concentrations at neck impingement and rim egress sites. The global model, validated by a cadaveric simulation in a servohydraulic hip simulator, included both hardware components and advanced anisotropic capsule characterization. Parametric computational runs explored the effect of cup orientation for both ceramic-on-ceramic and metal-on-metal bearing couples for two distinct motion sequences associated with dislocation. Results Stress concentrations from impingement increased nearly linearly with increased cup tilt and with cup anteversion. In some situations, peak values of stress approached or exceeded 1 GPa, levels challenging the yield strength of cobalt-chromium implants, and potentially the fracture strength of ceramics. The tendency for impingement events to generate debris, indexed in terms of a new scraping severity metric, showed orientation dependences similar to that for bulk material failure. Conclusions Damage propensity arising from impingement events in hard total hip bearings is highly orientation-dependent. PMID:20953853

  5. Hip fracture surgery

    MedlinePlus

    ... thigh bone. The thigh bone is called the femur. It is part of the hip joint. Hip pain is a related topic. ... to 4 hours. If you have an intertrochanteric fracture (the area below the femur neck), your surgeon will use a special metal ...

  6. Formed HIP Can Processing

    SciTech Connect

    Clarke, Kester Diederik

    2015-07-27

    The intent of this report is to document a procedure used at LANL for HIP bonding aluminum cladding to U-10Mo fuel foils using a formed HIP can for the Domestic Reactor Conversion program in the NNSA Office of Material, Management and Minimization, and provide some details that may not have been published elsewhere. The HIP process is based on the procedures that have been used to develop the formed HIP can process, including the baseline process developed at Idaho National Laboratory (INL). The HIP bonding cladding process development is summarized in the listed references. Further iterations with Babcock & Wilcox (B&W) to refine the process to meet production and facility requirements is expected.

  7. Topographic and Morphologic Evidence for Flooding of Ganymede's Resurfaced Terrains by Low-Viscosity Water-Ice Lavas

    NASA Technical Reports Server (NTRS)

    McKinnon, W. B.; Schenk, P. M.; Moore, J. M.

    2001-01-01

    Topographic mapping in at least three distinct regions of Ganymede reveals that smooth terrains are flat and are topographically depressed. This and embayment relationships are consistent with volcanic resurfacing. Additional information is contained in the original extended abstract.

  8. Surface and Subsurface Analyses of Metal-on-Polyethylene Total Hip Replacement Retrievals.

    PubMed

    Vuong, Vicky; Pettersson, Maria; Persson, Cecilia; Larsson, Sune; Grandfield, Kathryn; Engqvist, Håkan

    2016-05-01

    Metal-on-polyethylene (MoP) articulations are one of the most reliable implanted hip prostheses. Unfortunately, long-term failure remains an obstacle to the service life. There is a lack of higher resolution research investigating the metallic surface component of MoP hip implants. This study investigates the surface and subsurface features of metallic cobalt chromium molybdenum alloy (CoCrMo) femoral head components from failed MoP retrievals. Unused prostheses were used for comparison to differentiate between wear-induced defects and imperfections incurred during implant manufacturing. The predominant scratch morphology observed on the non-implanted references was shallow and linear, whereas the scratches on the retrievals consisted of largely nonlinear, irregular scratches of varying depth (up to 150 nm in retrievals and up to 60 nm in reference samples). Characteristic hard phases were observed on the surface and subsurface material of the cast samples. Across all samples, a 100-400 nm thick nanocrystalline layer was visible in the immediate subsurface microstructure. Although observation of the nanocrystalline layer has been reported in metal-on-metal articulations, its presence in MoP retrievals and unimplanted prostheses has not been extensively examined. The results suggest that manufacturing-induced surface and subsurface microstructural features are present in MoP hip prostheses prior to implantation and naturally, these imperfections may influence the in vivo wear processes after implantation. PMID:26399989

  9. Microscopical analysis of synovial fluid wear debris from failing CoCr hip prostheses

    NASA Astrophysics Data System (ADS)

    Ward, M. B.; Brown, A. P.; Cox, A.; Curry, A.; Denton, J.

    2010-07-01

    Metal on metal hip joint prostheses are now commonly implanted in patients with hip problems. Although hip replacements largely go ahead problem free, some complications can arise such as infection immediately after surgery and aseptic necrosis caused by vascular complications due to surgery. A recent observation that has been made at Manchester is that some Cobalt Chromium (CoCr) implants are causing chronic pain, with the source being as yet unidentified. This form of replacement failure is independent of surgeon or hospital and so some underlying body/implant interface process is thought to be the problem. When the synovial fluid from a failed joint is examined particles of metal (wear debris) can be found. Transmission Electron Microscopy (TEM) has been used to look at fixed and sectioned samples of the synovial fluid and this has identified fine (< 100 nm) metal and metal oxide particles within the fluid. TEM EDX and Electron Energy Loss Spectroscopy (EELS) have been employed to examine the composition of the particles, showing them to be chromium rich. This gives rise to concern that the failure mechanism may be associated with the debris.

  10. Surface and Subsurface Analyses of Metal-on-Polyethylene Total Hip Replacement Retrievals.

    PubMed

    Vuong, Vicky; Pettersson, Maria; Persson, Cecilia; Larsson, Sune; Grandfield, Kathryn; Engqvist, Håkan

    2016-05-01

    Metal-on-polyethylene (MoP) articulations are one of the most reliable implanted hip prostheses. Unfortunately, long-term failure remains an obstacle to the service life. There is a lack of higher resolution research investigating the metallic surface component of MoP hip implants. This study investigates the surface and subsurface features of metallic cobalt chromium molybdenum alloy (CoCrMo) femoral head components from failed MoP retrievals. Unused prostheses were used for comparison to differentiate between wear-induced defects and imperfections incurred during implant manufacturing. The predominant scratch morphology observed on the non-implanted references was shallow and linear, whereas the scratches on the retrievals consisted of largely nonlinear, irregular scratches of varying depth (up to 150 nm in retrievals and up to 60 nm in reference samples). Characteristic hard phases were observed on the surface and subsurface material of the cast samples. Across all samples, a 100-400 nm thick nanocrystalline layer was visible in the immediate subsurface microstructure. Although observation of the nanocrystalline layer has been reported in metal-on-metal articulations, its presence in MoP retrievals and unimplanted prostheses has not been extensively examined. The results suggest that manufacturing-induced surface and subsurface microstructural features are present in MoP hip prostheses prior to implantation and naturally, these imperfections may influence the in vivo wear processes after implantation.

  11. Hip arthroplasty with high chromium and cobalt blood levels--Case report of a patient followed during pregnancy and lactation period.

    PubMed

    Oppermann, Marc; Borisch, Cornelia; Schaefer, Christof

    2015-06-01

    Metal-on-metal arthroplasty may lead to elevated blood chromium (Cr) and cobalt (Co) levels (>7 μg/l). Since carcinogenic, mutagenic, and teratogenic effects have been suggested, there is concern of pregnancy hazards for women with this condition. The 34-year-old patient has had a unilateral hip replacement for seven years. Before her pregnancy high Cr (47 μg/l) and Co (103 μg/l) blood concentrations were measured, but she did not develop any symptoms. A male infant was delivered after 41 weeks with first degree hypospadias. His levels were increased at 3 weeks of age: 14 μg/l (Cr) and 20 μg/l (Co), but decreased by 9 weeks to 6.7 μg/l (Cr) and 10.0 μg/l (Co). Maternal levels at delivery were 25 μg/l (Cr) and 51 μg/l (Co). The child was fully breast-fed and developed normally. An association between hypospadias and Cr/Co has to be considered speculative. The otherwise favorable outcome of this case may be reassuring for pregnant and breast-feeding patients with metal-on-metal hip replacements. PMID:25828057

  12. "Active" and "Passive" Lava Resurfacing Processes on Io: A Comparative Study of Loki Patera and Prometheus

    NASA Technical Reports Server (NTRS)

    Davies, A. G.; Matson, D. L.; Leone, G.; Wilson, L.; Keszthelyi, L. P.

    2004-01-01

    Studies of Galileo Near Infrared Mapping Spectrometer (NIMS) data and ground based data of volcanism at Prometheus and Loki Patera on Io reveal very different mechanisms of lava emplacement at these two volcanoes. Data analyses show that the periodic nature of Loki Patera s volcanism from 1990 to 2001 is strong evidence that Loki s resurfacing over this period resulted from the foundering of a crust on a lava lake. This process is designated passive , as there is no reliance on sub-surface processes: the foundering of the crust is inevitable. Prometheus, on the other hand, displays an episodicity in its activity which we designate active . Like Kilauea, a close analog, Prometheus s effusive volcanism is dominated by pulses of magma through the nearsurface plumbing system. Each system affords views of lava resurfacing processes through modelling.

  13. Science writing competition: Hip, hip, hooray!

    PubMed

    Pewsey, Emma

    2013-03-12

    X-rays are best known for showing where bones have fractured, but researchers can also use X-rays to investigate why bones break, which could lead to treatments that reduce the number of elderly people who suffer broken hips.

  14. Measurement of the migration of a focal knee resurfacing implant with radiostereometry

    PubMed Central

    2014-01-01

    Background and purpose Articular resurfacing metal implants have been developed to treat full-thickness localized articular cartilage defects. Evaluation of the fixation of these devices is mandatory. Standard radiostereometry (RSA) is a validated method for evaluation of prosthetic migration, but it requires that tantalum beads are inserted into the implant. For technical reasons, this is not possible for focal articular resurfacing components. In this study, we therefore modified the tip of an articular knee implant and used it as a marker for RSA, and then validated the method. Material and methods We modified the tip of a resurfacing component into a hemisphere with a radius of 3 mm, marked it with a 1.0-mm tantalum marker, and implanted it into a sawbone marked with 6 tantalum beads. Point-motion RSA of the “hemisphere bead” using standard automated RSA as the gold standard was compared to manual measurement of the tip hemisphere. 20 repeated stereograms with gradual shifts of position of the specimen between each double exposure were used for the analysis. The tip motion was compared to the point motion of the hemisphere bead to determine the accuracy and precision. Results The accuracy of the manual tip hemisphere method was 0.08–0.19 mm and the precision ranged from 0.12 mm to 0.33 mm. Interpretation The accuracy and precision for translations is acceptable when using a small hemisphere at the tip of a focal articular knee resurfacing implant instead of tantalum marker beads. Rotations of the implant cannot be evaluated. The method is accurate and precise enough to allow detection of relevant migration, and it will be used for future clinical trials with the new implant. PMID:24286562

  15. Volcanically embayed craters on Venus: testing the catastrophic and equilibrium resurfacing models

    NASA Astrophysics Data System (ADS)

    Ivanov, M. A.; Head, J. W.

    2015-02-01

    Two major types of volcanic units, older regional plains and younger lobate plains, make up ~50% of the surface of Venus and represent different epochs of volcanism. The abundance of impact craters partially embayed from the exterior by each of these two types of units permits the testing of the key points of the model of equilibrium resurfacing. The proportion of craters embayed by the older regional plains is ~3%, which requires the typical size of a volcanic resurfacing event to be ~2700 km (~25° of angular diameter) in the framework of the equilibrium model. These event dimensions are inconsistent with the quasi-random spatial distribution of the craters. The proportion of craters embayed by younger lobate plains is 33%, which can be achieved if the characteristic size of the resurfacing event is less than ~160 km (~1.5° of angular diameter). Events of this size do not disturb the character of the spatial distribution of craters. We conclude that the style of volcanic resurfacing on Venus has changed significantly during its observable portion of the geologic history. During the global volcanic regime when regional plains were emplaced, volcanism acted in large regions and the process of formation of regional plains was more intensive than accumulation of impact craters. This led to the very small proportion of embayed craters (~3%). Later, during the network-rifting and volcanism regime (emplacement of lobate plains), volcanic sources were localized at distinctive centers, the net volcanic intensity decreased and became comparable to the rate of accumulation of craters, which resulted in much larger percentage (33%) of craters embayed by lobate plains.

  16. Autologous matrix-induced chondrogenesis (AMIC). A one-step procedure for retropatellar articular resurfacing.

    PubMed

    Benthien, Jan Philipp; Behrens, Peter

    2010-04-01

    The objective of this technical note is to describe the autologous matrix induced chondrogenesis (AMIC) procedure and to evaluate its possible role for resurfacing of retropatellar cartilage defects. AMIC is a one-step procedure combining microfracturing with application of a collagen I/III membrane to protect the initial blood clot and to serve as a scaffold for the developing chondrocytes. A retrospective analysis of our experience in three patients followed for 18 months is presented.

  17. Dione's resurfacing history as determined from a global impact crater database

    NASA Astrophysics Data System (ADS)

    Kirchoff, Michelle R.; Schenk, Paul

    2015-08-01

    Saturn's moon Dione has an interesting and unique resurfacing history recorded by the impact craters on its surface. In order to further resolve this history, we compile a crater database that is nearly global for diameters (D) equal to and larger than 4 km using standard techniques and Cassini Imaging Science Subsystem images. From this database, spatial crater density maps for different diameter ranges are generated. These maps, along with the observed surface morphology, have been used to define seven terrain units for Dione, including refinement of the smooth and "wispy" (or faulted) units from Voyager observations. Analysis of the terrains' crater size-frequency distributions (SFDs) indicates that: (1) removal of D ≈ 4-50 km craters in the "wispy" terrain was most likely by the formation of D ≳ 50 km craters, not faulting, and likely occurred over a couple billion of years; (2) resurfacing of the smooth plains was most likely by cryovolcanism at ∼2 Ga; (3) most of Dione's largest craters (D ⩾ 100 km), including Evander (D = 350 km), may have formed quite recently (<2 Ga), but are still relaxed, indicating Dione has been thermally active for at least half its history; and (4) the variation in crater SFDs at D ≈ 4-15 km is plausibly due to different levels of minor resurfacing (mostly subsequent large impacts) within each terrain.

  18. Patellar resurfacing in total knee arthroplasty: functional outcome differs with different outcome scores

    PubMed Central

    Aunan, Eirik; Næss, Grethe; Clarke-Jenssen, John; Sandvik, Leiv; Kibsgård, Thomas Johan

    2016-01-01

    Background and purpose — Recent research on outcomes after total knee arthroplasty (TKA) has raised the question of the ability of traditional outcome measures to distinguish between treatments. We compared functional outcomes in patients undergoing TKA with and without patellar resurfacing, using the knee injury and osteoarthritis outcome score (KOOS) as the primary outcome and 3 traditional outcome measures as secondary outcomes. Patients and methods — 129 knees in 115 patients (mean age 70 (42–82) years; 67 female) were evaluated in this single-center, randomized, double-blind study. Data were recorded preoperatively, at 1 year, and at 3 years, and were assessed using repeated-measures mixed models. Results — The mean subscores for the KOOS after surgery were statistically significantly in favor of patellar resurfacing: sport/recreation, knee-related quality of life, pain, and symptoms. No statistically significant differences between the groups were observed with the Knee Society clinical rating system, with the Oxford knee score, and with visual analog scale (VAS) for patient satisfaction. Interpretation — In the present study, the KOOS—but no other outcome measure used—indicated that patellar resurfacing may be beneficial in TKA. PMID:26540368

  19. Surface Ages and Resurfacing Rates of the Polar Layered Deposits on Mars

    USGS Publications Warehouse

    Herkenhoff, K. E.; Plaut, J.J.

    2000-01-01

    Interpretation of the polar stratigraphy of Mars in terms of global climate changes is complicated by the significant difference in surface ages between the north and south polar layered terrains inferred from crater statistics. We have reassessed the cratering record in both polar regions using Viking Orbiter and Mariner 9 images. No craters have been found in the north polar layered terrain, but the surface of most of the south polar layered deposits appears to have been stable for many of the orbital/axial cycles that are thought to have induced global climate changes on Mars. The inferred surface age of the south polar layered deposits (about 10 Ma) is two orders of magnitude greater than the surface age of the north polar layered deposits and residual cap (at most 100 ka). Similarly, modeled resurfacing rates are at least 20 times greater in the north than in the south. These results are consistent with the hypotheses that polar layered deposit resurfacing rates are highest in areas covered by perennial ice and that the differences in polar resurfacing rates result from the 6.4 km difference in elevation between the polar regions. Deposition on the portion of the south polar layered deposits that is not covered by the perennial ice cap may have ceased about 5 million years ago when the obliquity of Mars no longer exceeded 40??. ?? 2000 Academic Press.

  20. Temperature, age and crust thickness distributions of Loki Patera on Io: implications for resurfacing mechanism

    NASA Technical Reports Server (NTRS)

    Davies, A. G.

    2003-01-01

    A high-spatial-resolution, multi-wavelength observation by the Galileo NIMS instrument has been analysed to determine the temperature and area distribution of a large portion of the ionian volcano Loki Patera. The temperatures of the cooler components from a two-temperature fit to the data can be used to determine ages of the surface. The age of the floor along a profile across the floor of the caldera ranges from 10 to 80 days. This puts the start of the resurfacing in July/early August 2001, yielding a resurfacing rate of approximately 1 km/day, with the new lava spreading from the SW corner of the caldera in a NE direction. This rate is consistent with resurfacing by foundering of the crust on a lava lake. However,the temperature distribution may also result from the emplacement of flows. Implied crust thicknesses (derived using a lava cooling model) range from 2.6 to 0.9 m.

  1. Complications in primary total hip arthroplasty: avoidance and management: wear.

    PubMed

    Ries, Michael D

    2003-01-01

    Many factors, including polyethylene processing, sterilization method, counterface material, femoral head size, femoral offset, acetabular component position, implant design, and patient activity level, affect the rate of wear in total hip arthroplasty. For patients with life expectancy that exceeds the longevity of the conventional implant materials, an alternative bearing surface (highly cross-linked polyethylene, metal-on-metal, or ceramic-on-ceramic) may be considered. Although laboratory wear tests with these materials are very favorable, clinical outcomes have not been clearly established. When osteolysis does develop in response to particulate debris, the location and progression of the lesions may be quite variable. Asymptomatic stable lesions can be followed clinically and radiographically while symptomatic or enlarging lesions or those that may compromise the integrity of the periprosthetic bone stock require surgery. If acetabular component revision is necessary and an adequate rim of host bone is maintained to support a revision acetabular component, defects can be filled with particulate bone graft. Large segmental defects generally require structural allografts. If the acetabular shell is well fixed in good position and the osteolytic defects are accessible, treatment with curettage and bone grafting of the lesions with liner revision is appropriate to avoid use of a structural allograft. Proximal femoral defects around a well-fixed stem can be managed in a similar manner with curettage and bone grafting. Distal lesions associated with risk of periprosthetic femur fracture or implant loosening require stem revision. Osteoclastic resportion of bone in response to particulate debris can be impaired with use of some drugs such as alendronate. However, the safety and efficacy of alendronate in the clinical management of osteolysis associated with total hip arthroplasty has not been established. PMID:12690853

  2. Hip arthroscopy in the setting of hip dysplasia

    PubMed Central

    Yeung, M.; Kowalczuk, M.; Simunovic, N.

    2016-01-01

    Objective Hip arthroscopy in the setting of hip dysplasia is controversial in the orthopaedic community, as the outcome literature has been variable and inconclusive. We hypothesise that outcomes of hip arthroscopy may be diminished in the setting of hip dysplasia, but outcomes may be acceptable in milder or borderline cases of hip dysplasia. Methods A systematic search was performed in duplicate for studies investigating the outcome of hip arthroscopy in the setting of hip dysplasia up to July 2015. Study parameters including sample size, definition of dysplasia, outcomes measures, and re-operation rates were obtained. Furthermore, the levels of evidence of studies were collected and quality assessment was performed. Results The systematic review identified 18 studies investigating hip arthroscopy in the setting of hip dysplasia, with 889 included patients. Criteria used by the studies to diagnose hip dysplasia and borderline hip dysplasia included centre edge angle in 72% of studies but the range of angles were quite variable. Although 89% of studies reported improved post-operative outcome scores in the setting of hip dysplasia, revision rates were considerable (14.1%), with 9.6% requiring conversion to total hip arthroplasty. Conclusion The available orthopaedic literature suggests that although improved outcomes are seen in hip arthroscopy in the setting of hip dysplasia, there is a high rate of re-operation and conversion to total hip arthroplasty. Furthermore, the criteria used to define hip dysplasia vary considerably among published studies. Cite this article: M. Yeung, M. Kowalczuk, N. Simunovic, O. R. Ayeni. Hip arthroscopy in the setting of hip dysplasia: A systematic review. Bone Joint Res 2016;5:225–231. DOI: 10.1302/2046-3758.56.2000533. PMID:27313136

  3. Hip replacement in femoral head osteonecrosis: current concepts

    PubMed Central

    Scaglione, Michelangelo; Fabbri, Luca; Celli, Fabio; Casella, Francesco; Guido, Giulio

    2015-01-01

    Summary Osteonecrosis of the femoral head is a destructive disease that usually affects young adults with high functional demands and can have devastating effects on hip joint. The treatment depends on extent and location of the necrosis lesion and on patient’s factors, that suggest disease progression, collapse probability and also implants survival. Non-idiopathic osteonecrosis patients had the worst outcome. There is not a gold standard treatment and frequently it is necessary a multidisciplinary approach. Preservation procedures of the femoral head are the first choice and can be attempted in younger patients without head collapse. Replacement procedure remains the main treatment after failure of preserving procedures and in the late-stage ONFH, involving collapse of the femoral head and degenerative changes to the acetabulum. Resurfacing procedure still has good results but the patient selection is a critical factor. Total hip arthroplasties had historically poor results in patients with osteonecrosis. More recently, reports have shown excellent results, but implant longevity and following revisions are still outstanding problems. PMID:27134633

  4. HIP OSTEOARTHRITIS AND WORK

    PubMed Central

    Harris, E Clare; Coggon, David

    2016-01-01

    Epidemiological evidence points strongly to a hazard of hip osteoarthritis from heavy manual work. Harmful exposures may be reduced by elimination or redesign of processes and use of mechanical aids. Reducing obesity might help to protect workers whose need to perform heavy lifting cannot be eliminated. Particularly high relative risks have been reported in farmers, and hip osteoarthritis is a prescribed occupational disease in the UK for long-term employees in agriculture. Even where it is not attributable to employment, hip osteoarthritis impacts importantly on capacity to work. Factors that may influence work participation include the severity of disease, the physical demands of the job, age, and the size of the employer. Published research does not provide a strong guide to the timing of return to work following hip arthroplasty for osteoarthritis, and it is unclear whether patients should avoid heavy manual tasks in their future employment. PMID:26612242

  5. Hip fracture - discharge

    MedlinePlus

    ... hemiarthroplasty to replace the ball part of your hip joint. You should have received physical therapy while you were in the hospital or at a rehabilitation center before going home from the hospital.

  6. Ultrasound: Infant Hip

    MedlinePlus

    ... hip area, and images are recorded on a computer. The black-and-white images show the internal ... the images can be seen clearly on the computer screen. A technician (sonographer) trained in ultrasound imaging ...

  7. Hip flexor strain - aftercare

    MedlinePlus

    ... such as sprinting, kicking, and changing direction while running or moving, can stretch and tear the hip flexors. Runners, people who do martial arts, and football, soccer, and hockey players are more likely to have ...

  8. Total knee replacement with and without patellar resurfacing: a prospective, randomised trial using the profix total knee system.

    PubMed

    Smith, A J; Wood, D J; Li, M-G

    2008-01-01

    We have examined the differences in clinical outcome of total knee replacement (TKR) with and without patellar resurfacing in a prospective, randomised study of 181 osteoarthritic knees in 142 patients using the Profix total knee system which has a femoral component with features considered to be anatomical and a domed patellar implant. The procedures were carried out between February 1998 and November 2002. A total of 159 TKRs in 142 patients were available for review at a mean of four years (3 to 7). The patients and the clinical evaluator were blinded in this prospective study. Evaluation was undertaken annually by an independent observer using the knee pain scale and the Knee Society clinical rating system. Specific evaluation of anterior knee pain, stair-climbing and rising from a seated to a standing position was also undertaken. No benefit was shown of TKR with patellar resurfacing over that without resurfacing with respect to any of the measured outcomes. In 22 of 73 knees (30.1%) with and 18 of 86 knees (20.9%) without patellar resurfacing there was some degree of anterior knee pain (p = 0.183). No revisions related to the patellofemoral joint were performed in either group. Only one TKR in each group underwent a re-operation related to the patellofemoral joint. A significant association between knee flexion contracture and anterior knee pain was observed in those knees with patellar resurfacing (p = 0.006). PMID:18160498

  9. The increase in cobalt release in metal-on-polyethylene hip bearings in tests with third body abrasives.

    PubMed

    de Villiers, Danielle; Traynor, Alison; Collins, Simon N; Shelton, Julia C

    2015-09-01

    Hypersensitivity reactions in patients receiving metal-on-metal hip replacements have been attributed to corrosion products as observed by elevated cobalt and chromium ions in the blood. Although the majority of cases are reported in metal-on-metal, incidences of these reactions have been reported in the metal-on-polyethylene patient population. To date, no in vitro study has considered cobalt release for this bearing combination. This study considered four 28 mm and seven 52 mm diameter metal-on-polyethylene bearings tested following ISO standard hip simulator conditions as well as under established abrasive conditions. These tests showed measurable cobalt in all bearings under standard conditions. Cobalt release, as well as polyethylene wear, increased with diameter, increasing from 52 to 255 ppb. The introduction of bone cement particles into the articulation doubled polyethylene wear and cobalt release while alumina particles produced significant damage on the heads demonstrated by cobalt levels of 70,700 ppb and an increased polyethylene wear from a mean value of 9-160 mm(3)/mc. Cobalt release was indicative of head damage and correlated with polyethylene wear at the next gravimetric interval. The removal of third body particles resulted in continued elevated cobalt levels in the 52 mm diameter bearings tested with alumina compared to standard conditions but the bearings tested with bone cement particles returned to standard levels. The polyethylene wear in the bone cement tested bearings also recovered to standard levels, although the alumina tested bearings continued to wear at a higher rate of 475 mm(3)/mc. Cobalt release was shown to occur in metal-on-polyethylene bearings indicating damage to the metal head resulting in increased polyethylene wear. While large diameter metal-on-polyethylene bearings may provide an increased range of motion and a reduced dislocation risk, increased levels of cobalt are likely to be released and this needs to be fully

  10. The increase in cobalt release in metal-on-polyethylene hip bearings in tests with third body abrasives.

    PubMed

    de Villiers, Danielle; Traynor, Alison; Collins, Simon N; Shelton, Julia C

    2015-09-01

    Hypersensitivity reactions in patients receiving metal-on-metal hip replacements have been attributed to corrosion products as observed by elevated cobalt and chromium ions in the blood. Although the majority of cases are reported in metal-on-metal, incidences of these reactions have been reported in the metal-on-polyethylene patient population. To date, no in vitro study has considered cobalt release for this bearing combination. This study considered four 28 mm and seven 52 mm diameter metal-on-polyethylene bearings tested following ISO standard hip simulator conditions as well as under established abrasive conditions. These tests showed measurable cobalt in all bearings under standard conditions. Cobalt release, as well as polyethylene wear, increased with diameter, increasing from 52 to 255 ppb. The introduction of bone cement particles into the articulation doubled polyethylene wear and cobalt release while alumina particles produced significant damage on the heads demonstrated by cobalt levels of 70,700 ppb and an increased polyethylene wear from a mean value of 9-160 mm(3)/mc. Cobalt release was indicative of head damage and correlated with polyethylene wear at the next gravimetric interval. The removal of third body particles resulted in continued elevated cobalt levels in the 52 mm diameter bearings tested with alumina compared to standard conditions but the bearings tested with bone cement particles returned to standard levels. The polyethylene wear in the bone cement tested bearings also recovered to standard levels, although the alumina tested bearings continued to wear at a higher rate of 475 mm(3)/mc. Cobalt release was shown to occur in metal-on-polyethylene bearings indicating damage to the metal head resulting in increased polyethylene wear. While large diameter metal-on-polyethylene bearings may provide an increased range of motion and a reduced dislocation risk, increased levels of cobalt are likely to be released and this needs to be fully

  11. The Hyperflexible Hip

    PubMed Central

    Weber, Alexander E.; Bedi, Asheesh; Tibor, Lisa M.; Zaltz, Ira; Larson, Christopher M.

    2015-01-01

    Context: Dance, gymnastics, figure skating, and competitive cheerleading require a high degree of hip range of motion. Athletes who participate in these sports use their hips in a mechanically complex manner. Evidence Acquisition: A search of the entire PubMed database (through December 2013) and additional searches of the reference lists of pertinent articles. Study Design: Systematic review. Level of Evidence: Level 3. Results: Whether innate or acquired, dancers and gymnasts have some hypermobility that allows their hips to be placed in potentially impinging or unstable positions required for their given activity. Such extremes of motion can result in both intra-articular and extra-articular impingement as well as compensatory osseous and muscular pathology. In addition, dancers and gymnasts are susceptible to impingement-induced instability. Dancers with innate generalized hyperlaxity are at increased risk of injury because of their activities and may require longer recovery times to return to play. Both nonoperative and operative treatments (arthroscopic and open) have an important role in returning flexibility athletes to their preoperative levels of sport and dance. Conclusion: Because of the extreme hip motion required and the compensatory soft tissue laxity in dancers and gymnasts, these athletes may develop instability, impingement, or combinations of both. This frequently occurs in the setting of subtle pathoanatomy or in patients with normal bony anatomy. With appropriate surgical indications and the correct operative technique, the treating surgeon can anticipate high levels of return to play for the gymnast and dancer with hip pain. PMID:26137181

  12. Bipolar hip arthroplasty.

    PubMed

    Chang, Qing; Liu, Shubing; Guan, Changyong; Yu, Fangyuan; Wu, Shenguang; Jiang, Changliang

    2011-12-01

    Our aim was to compare hip arthroplasty with internal screw fixation in the repair of intertrochanteric fractures in elderly patients with osteoporosis. Of 112 included patient, 70 (81.81 ± 4.88 years) received hip arthroplasty with a prosthesis specially designed for intertrochanteric fractures, and 42 (83.46 ± 5.11 years) underwent plate-screw fixation. The hip arthroplasty group had significantly longer operation time, intraoperative blood loss, and total volume of blood transfused but had shorter time to beginning weight-bearing (5.94 ± 2.76 vs 23.68 ± 22.01 days) and higher postoperative Harris hip score (91.37 ± 4.80 vs 86.14 ± 5.46). In the arthroplasty group, there were 2 dislocations; and in the plate-screw fixation group, there were 5 internal fixation failures. Hip arthroplasty is preferable to internal fixation in elderly patients (age >80 years) with osteoporosis. PMID:21530148

  13. Hip impingement: beyond femoroacetabular

    PubMed Central

    Bardakos, Nikolaos V.

    2015-01-01

    In the last 20 years, femoroacetabular impingement has been at the forefront of clinical practice as a cause of hip pain in young adults. As arthroscopic techniques for the hip continue to evolve, the possible presence of a new group of conditions creating mechanical conflict in and around the hip joint (ischiofemoral, subspine and iliopsoas impingement) has recently been elucidated whilst interest in already known ‘impingement’ syndromes (pelvic-trochanteric and pectineofoveal impingement) is now revived. This article attempts to increase awareness of these relatively uncommon clinical entities by describing their pathomorphology, contact mechanics, treatment and published results available to present. It is hoped that such knowledge will diversify therapeutic options for the clinician, thereby improving outcomes in a small but not negligible portion of patients with previously unexplained persistent symptoms. PMID:27011843

  14. Impact crater densities on volcanoes and coronae on venus: implications for volcanic resurfacing.

    PubMed

    Namiki, N; Solomon, S C

    1994-08-12

    The density of impact craters on large volcanoes on Venus is half the average crater density for the planet. The crater density on some classes of coronae is not significantly different from the global average density, but coronae with extensive associated volcanic deposits have lower crater densities. These results are inconsistent with both single-age and steady-state models for global resurfacing and suggest that volcanoes and coronae with associated volcanism have been active on Venus over the last 500 million years.

  15. [Resurfacing of a trochanteric pressure sore by a pedicled fasciocutaneous anterolateral thigh flap: a case report].

    PubMed

    Zeitoun, J; Faghahati, S; Burin Des Roziers, B; Daoud, G; Cartier, S

    2013-06-01

    The anterolateral thigh flap is usually used as a free flap for various kinds of reconstruction and resurfacing of distant areas. Cover of a deep trochanteric pressure sore is commonly made by muscular or musculocutaneous flaps such as tensor of fascia lata or vastus lateralis. We report the case of a trochanteric pressure sore covered by a fasciocutaneous pedicled anterolateral thigh flap after negative pressure therapy in a 58-year-old paraplegic patient. After 6 months, a good quality of coverage was obtained with minimal morbidity of donor site. The pedicled fasciocutaneous anterolateral flap appears as a reliable option for the treatment of trochanteric pressure sore.

  16. First metacarpal resurfacing with polyvinyl alcohol implant in osteoarthritis: preliminary study.

    PubMed

    Taleb, C; Berner, S; Mantovani Ruggiero, G

    2014-06-01

    Osteoarthritis of first carpometacarpal (CMC) joint is a condition that is frequently encountered in hand surgery. If conservative treatment fails, several surgical procedures are available ranging from arthroscopic debridement to total joint arthroplasty. This study focuses on a new resurfacing technique for the base of the first metacarpal using a polyvinyl alcohol hydrogel implant. Our preliminary study found good clinical outcomes and no inflammatory reaction after a follow-up of 30 months. However prospective studies with a longer follow-up and more patient are needed to confirm these results.

  17. Assessing Cryovolcanic Resurfacing of Titan: Implications for Detection of Active Cryolavas

    NASA Astrophysics Data System (ADS)

    Davies, A. G.; Matson, D. L.; Castillo-Rogez, J. C.; Sotin, C.; Johnson, T. V.

    2009-04-01

    Cryovolcanism has been proposed for resurfacing Saturn's moon Titan (see references in [1]). We have quantitatively examined the constraints on cryovolcanic resurfacing, and the likelihood of detection of active flows by instruments on the Cassini spacecraft. If the surface of Titan has an age of order 0.5 Ga, then the entire satellite is resurfaced in this time by a net rate of areal coverage of only 0.17 km2 year-1 (53 cm2 s-1), erasing most impact craters. In comparison with Earth, this coverage rate is less than the average rate for many contemporaneous terrestrial volcanic flows. For example, at Kilauea volcano, Hawai'i, the average coverage rate for a flow is of order ~1 m2 s-1: on Titan, this rate would cover the entire surface ~200 times in 0.5 Ga, if the activity was distributed evenly. If the flows were 1 m thick, the total volume erupted in this time would still only be 0.4% of the volume of a 50 km thick crust. At the other end of the flow effusion-rate scale, the largest eruptions on Earth emplaced massive basalt flows, each ~10-100 m thick (e.g., Deccan Traps, India). Areal coverage rates would have been of order ~1000 m2 s-1. This coverage rate would cover the entire surface of Titan in less than 3000 years, an unfeasible scenario. The analogue comparisons suggest that only a relatively very small amount of effusive activity (e.g., much less than current activity at Kilauea) is required to resurface Titan in 0.5 Ga. If so, the detection of active eruptions may be very difficult with the Cassini Visible-Infrared Mapping Spectrometer (VIMS) and the Composite Infrared Spectrometer (CIRS). If activity is confined to specific locations, then the chances of detection increase: our modelling of cryolavas [2] suggests that the signature of such activity can be detected by CIRS (and possibly VIMS) if the extent and areal coverage rates are high enough. This work was performed at the Jet Propulsion Laboratory-California Institute of Technology, under contract

  18. Observation of the post-inflammatory hyperpigmentation of the face laser resurfacing in China

    NASA Astrophysics Data System (ADS)

    Lin, Xiao-Hua; Wu, Hui-Zhen

    1998-11-01

    There were one hundred Chinese cases treated with face laser resurfacing. Observed the result, the post-inflammatory hyperpigmentation was found in all case. It is not any use that the cases used the 3 percent hydroquinone before the operation. Eighty-five cases were going down between two and six months after the operation. Fifteen cases continued to nine months. Five cases continued to a year. Cosmetics are possible to affect the course of inflammatory hyperpigmentation. Hyperpigmentation disappeared more quickly while using 3 percent hydroquinone cream or KA cream after the operation. And intravenous injections with vitamin C is helpful.

  19. Hip joint replacement - series (image)

    MedlinePlus

    ... hip socket. The socket is usually made of metal. A liner that fits inside the socket. It ... usually plastic, but some surgeons use ceramic and metal. The liner allows the hip to move smoothly. ...

  20. Basic principles and uniform terminology for the head-neck junction in hip replacement.

    PubMed

    Werner, Paul H; Ettema, Harmen B; Witt, Florian; Morlock, Michael M; Verheyen, Cees C P M

    2015-01-01

    Recent problems with large head metal on metal hip replacements have spiked renewed interest in the head-neck junction. A thorough knowledge of the principles of the locking mechanism, the assembly technique and affecting factors on the strength of this junction is needed. Currently a confusing variability in terms is used to describe this junction. This overcomplicates an already complex issue. The purpose of this literature review is to collect and list the different terms used and to propose a uniform terminology. Two authors independently searched the electronic databases of PubMed, CINAHL and MEDLINE with specific key words and combinations according to the PRISMA guidelines. The initial search yielded a total of 518 articles with ultimately 53 articles included in the present analysis. No consensus for a uniform term for the 2 sides of the head-stem junction was found. Since there is already pronounced variability in taper designs between different manufacturers (even so similarly named, e.g. "12/14"), a uniform terminology could be the first step to simplify the situation. "Male" and "female taper" is proposed as the appropriate terminology for the stem and head junction in hip replacement, respectively. The importance of the assembly technique understanding the principles of the locking mechanism is emphasised. PMID:25362881

  1. Hard-on-Hard Lubrication in the Artificial Hip under Dynamic Loading Conditions

    PubMed Central

    Sonntag, Robert; Reinders, Jörn; Rieger, Johannes S.; Heitzmann, Daniel W. W.; Kretzer, J. Philippe

    2013-01-01

    The tribological performance of an artificial hip joint has a particularly strong influence on its success. The principle causes for failure are adverse short- and long-term reactions to wear debris and high frictional torque in the case of poor lubrication that may cause loosening of the implant. Therefore, using experimental and theoretical approaches models have been developed to evaluate lubrication under standardized conditions. A steady-state numerical model has been extended with dynamic experimental data for hard-on-hard bearings used in total hip replacements to verify the tribological relevance of the ISO 14242-1 gait cycle in comparison to experimental data from the Orthoload database and instrumented gait analysis for three additional loading conditions: normal walking, climbing stairs and descending stairs. Ceramic-on-ceramic bearing partners show superior lubrication potential compared to hard-on-hard bearings that work with at least one articulating metal component. Lubrication regimes during the investigated activities are shown to strongly depend on the kinematics and loading conditions. The outcome from the ISO gait is not fully confirmed by the normal walking data and more challenging conditions show evidence of inferior lubrication. These findings may help to explain the differences between the in vitro predictions using the ISO gait cycle and the clinical outcome of some hard-on-hard bearings, e.g., using metal-on-metal. PMID:23940772

  2. Hard-on-hard lubrication in the artificial hip under dynamic loading conditions.

    PubMed

    Sonntag, Robert; Reinders, Jörn; Rieger, Johannes S; Heitzmann, Daniel W W; Kretzer, J Philippe

    2013-01-01

    The tribological performance of an artificial hip joint has a particularly strong influence on its success. The principle causes for failure are adverse short- and long-term reactions to wear debris and high frictional torque in the case of poor lubrication that may cause loosening of the implant. Therefore, using experimental and theoretical approaches models have been developed to evaluate lubrication under standardized conditions. A steady-state numerical model has been extended with dynamic experimental data for hard-on-hard bearings used in total hip replacements to verify the tribological relevance of the ISO 14242-1 gait cycle in comparison to experimental data from the Orthoload database and instrumented gait analysis for three additional loading conditions: normal walking, climbing stairs and descending stairs. Ceramic-on-ceramic bearing partners show superior lubrication potential compared to hard-on-hard bearings that work with at least one articulating metal component. Lubrication regimes during the investigated activities are shown to strongly depend on the kinematics and loading conditions. The outcome from the ISO gait is not fully confirmed by the normal walking data and more challenging conditions show evidence of inferior lubrication. These findings may help to explain the differences between the in vitro predictions using the ISO gait cycle and the clinical outcome of some hard-on-hard bearings, e.g., using metal-on-metal.

  3. Precaution, governance and the failure of medical implants: the ASR((TM)) hip in the UK.

    PubMed

    Wienroth, Matthias; McCormack, Pauline; Joyce, Thomas J

    2014-01-01

    Hip implants have provided life-changing treatment, reducing pain and improving the mobility and independence of patients. Success has encouraged manufacturers to innovate and amend designs, engendering patient hopes in these devices. However, failures of medical implants do occur. The failure rate of the Articular Surface Replacement metal-on-metal hip system, implanted almost 100,000 times world-wide, has re-opened debate about appropriate and timely implant governance. As commercial interests, patient hopes, and devices' governance converge in a socio-technical crisis, we analyse the responses of relevant governance stakeholders in the United Kingdom between 2007 and 2014. We argue that there has been a systemic failure of the governance system entrusted with the safety of patients fitted with medical implants. Commercial considerations of medical implants and the status quo of medical implant governance have been given priority over patient safety despite the availability of significant failure data in an example of uncertainty about what constitutes appropriate precautionary action. PMID:26573983

  4. Hard-on-hard lubrication in the artificial hip under dynamic loading conditions.

    PubMed

    Sonntag, Robert; Reinders, Jörn; Rieger, Johannes S; Heitzmann, Daniel W W; Kretzer, J Philippe

    2013-01-01

    The tribological performance of an artificial hip joint has a particularly strong influence on its success. The principle causes for failure are adverse short- and long-term reactions to wear debris and high frictional torque in the case of poor lubrication that may cause loosening of the implant. Therefore, using experimental and theoretical approaches models have been developed to evaluate lubrication under standardized conditions. A steady-state numerical model has been extended with dynamic experimental data for hard-on-hard bearings used in total hip replacements to verify the tribological relevance of the ISO 14242-1 gait cycle in comparison to experimental data from the Orthoload database and instrumented gait analysis for three additional loading conditions: normal walking, climbing stairs and descending stairs. Ceramic-on-ceramic bearing partners show superior lubrication potential compared to hard-on-hard bearings that work with at least one articulating metal component. Lubrication regimes during the investigated activities are shown to strongly depend on the kinematics and loading conditions. The outcome from the ISO gait is not fully confirmed by the normal walking data and more challenging conditions show evidence of inferior lubrication. These findings may help to explain the differences between the in vitro predictions using the ISO gait cycle and the clinical outcome of some hard-on-hard bearings, e.g., using metal-on-metal. PMID:23940772

  5. Friction of total hip replacements with different bearings and loading conditions.

    PubMed

    Brockett, Claire; Williams, Sophie; Jin, Zhongmin; Isaac, Graham; Fisher, John

    2007-05-01

    Metal-on-ultra-high molecular weight polyethylene (UHMWPE) total hip replacements have been the most popular and clinically successful implants to date. However, it is well documented that the wear debris from these prostheses contributes to osteolysis and ultimate failure of the prosthesis, hence alternative materials have been sought. A range of 28 mm diameter bearings were investigated using a hip friction simulator, including conventional material combinations such as metal-on-UHWMPE, ceramic-on-ceramic (CoC), and metal-on-metal (MoM), as well as novel ceramic-on-metal (CoM) pairings. Studies were performed under different swing-phase load and lubricant conditions. The friction factors were lowest in the ceramic bearings, with the CoC bearing having the lowest friction factor in all conditions. CoM bearings also had low friction factors compared with MoM, and the trends were similar to CoC bearings for all test conditions. Increasing swing phase load was shown to cause an increase in friction factor in all tests. Increased serum concentration resulted in increased friction factor in all material combinations, except MoM, where increased serum concentration produced a significant reduction in friction factor.

  6. Implant Optimisation for Primary Hip Replacement in Patients over 60 Years with Osteoarthritis: A Cohort Study of Clinical Outcomes and Implant Costs Using Data from England and Wales

    PubMed Central

    Jameson, Simon S.; Mason, James; Baker, Paul N.; Gregg, Paul J.; Deehan, David J.; Reed, Mike R.

    2015-01-01

    Background Hip replacement is one of the most commonly performed surgical procedures worldwide; hundreds of implant configurations provide options for femoral head size, joint surface material and fixation method with dramatically varying costs. Robust comparative evidence to inform the choice of implant is needed. This retrospective cohort study uses linked national databases from England and Wales to determine the optimal type of replacement for patients over 60 years undergoing hip replacement for osteoarthritis. Methods and Findings Implants included were the commonest brand from each of the four types of replacement (cemented, cementless, hybrid and resurfacing); the reference prosthesis was the cemented hip procedure. Patient reported outcome scores (PROMs), costs and risk of repeat (revision) surgery were examined. Multivariable analyses included analysis of covariance to assess improvement in PROMs (Oxford hip score, OHS, and EQ5D index) (9159 linked episodes) and competing risks modelling of implant survival (79,775 procedures). Cost of implants and ancillary equipment were obtained from National Health Service procurement data. Results EQ5D score improvements (at 6 months) were similar for all hip replacement types. In females, revision risk was significantly higher in cementless hip prostheses (hazard ratio, HR = 2.22, p<0.001), when compared to the reference hip. Although improvement in OHS was statistically higher (22.1 versus 20.5, p<0.001) for cementless implants, this small difference is unlikely to be clinically important. In males, revision risk was significantly higher in cementless (HR = 1.95, p = 0.003) and resurfacing implants, HR = 3.46, p<0.001), with no differences in OHS. Material costs were lowest with the reference implant (cemented, range £1103 to £1524) and highest with cementless implants (£1928 to £4285). Limitations include the design of the study, which is intrinsically vulnerable to omitted variables, a paucity of long

  7. Biologic resurfacing of the ankle and first metatarsophalangeal joint: case studies with a 2-year follow-up.

    PubMed

    Brigido, Stephen A; Troiano, Michael; Schoenhaus, Harold

    2009-10-01

    The goal of biologic resurfacing is to provide a smooth joint surface with a low coefficient of friction, which allows the joint to function with near normal biomechanics, as well as provide intermittent pressure, to the subchondral and cancellous bone. This unique combination often results in the formation of a "neocartilage-like" structure that can reduce pain and restore biomechanics. As well as giving a brief history of cutis arthroplasty, this article describes cases in which the ankle and first metatarsophalangeal joint underwent biologic resurfacing, with a 2-year postoperative follow up.

  8. Use of 1540nm fractionated erbium:glass laser for split skin graft resurfacing: a case study.

    PubMed

    Narinesingh, S; Lewis, S; Nayak, B S

    2013-09-01

    The field of laser skin resurfacing has evolved rapidly over the past two decades from ablative lasers, to nonablative systems using near-infrared, intense-pulsed light and radio-frequency systems, and most recently fractional laser resurfacing. Although fractional thermolysis is still in its infancy, its efficacy in in the treatment of skin disorders have been clearly demonstrated. Here we present a case report on the safety and efficacy of a 1540nm erbium:glass laser in the treatment of the waffle pattern of a meshed skin graft in a 38-year-old patient with type V skin in the Caribbean.

  9. Ceramic on ceramic hip arthroplasty in fused hips

    PubMed Central

    Park, Kyung-Soon; Yoon, Taek-Rim; Lee, Tae-Min; Ahn, Yeong-Seub

    2015-01-01

    Background: Most literature in the field of total hip arthroplasty (THA) for fused hips, until date has reported the results of using metal on polyethylene and ceramic on polyethylene bearings. Results of THA using ceramic on ceramic (CoC) bearings in fused hips have not been published in literature. This study reports the results of cementless THA using CoC articulation perfomed in fused hips. Materials and Methods: Twenty-three patients (25 hips) with fused hips underwent conversion to THA using CoC bearings and were followed up for a mean 5.4 years. The conventional posterolateral approach was used in 15 hips, a modified two incision technique in 7 hips and a direct lateral approach with greater trochanteric osteotomy in 3 hips. Postoperatively, range of motion exercises were encouraged after 2–3 days of bed rest and subsequent gradual weight bearing using crutches was begun. Results: Mean Harris hip score improved from 42.4 to 84.2 and mean leg lengthening of 36.6 mm was achieved. In the average 5.4 years (range 2.8-9.1 years) followup there were no cases with osteolysis around acetabular cup and femoral stem. In this study, there was no case of ceramic fracture. There was one case of squeaking. Conclusion: This study suggests that cementless THA performed for fused hips with CoC bearings can provide good early clinical results. PMID:26015635

  10. HIP quench technology

    SciTech Connect

    Bergman, C.; Westerlund, J.; Zimmerman, F.X.

    1996-12-31

    Hot Isostatic Pressing (HIP) is a viable production process today for densifying metals, ceramics, and composites to achieve fully dense parts. One major drawback for conventional HIPing is the long ten to twelve hour cycle time resulting in low productivity and high processing cost. Drastic furnace improvements have been made in the late 1980`s with the advent of Uniform Rapid Cooling (URC) called HIP Quenching. This innovation allows floor/floor cycles as short as four to five hours with one hour soak depending on the material to be HIPed. A flow device such as a fan is utilized at the base of the furnace for forced gas convection in promoting main features to: (1) accelerate time for heating, soaking and cooling; (2) add combined solution heat treating; and (3) reduce thermal distortion of parts with varying cross-sections. All three points promise to positively effect better economy with improved property and quality to promote the HIP process further. This paper describes the URC technology and illustrates a couple of HIP Quench studies made for a turbine disc and efficient High Speed Steel powder consolidation.

  11. Congenital hip dislocation (image)

    MedlinePlus

    ... by a blow, fall, or other trauma, a dislocation can also occur from birth. The cause is unknown but genetic factors may play a role. Problems resulting from very mild developmental dysplasia of the hip may not become apparent until the person is ...

  12. INL HIP Plate Fabrication

    SciTech Connect

    B. H. Park; C. R. Clark; J. F. Jue

    2010-02-01

    This document outlines the process used to bond monolithic fuel plates by Hot Isostatic Pressing (HIP). This method was developed at Idaho National Laboratory (INL) for the Reduced Enrichment for Research and Test Reactors (RERTR) program. These foils have been used in a number of irradiation experiments in support of the United States Global Threat Reduction Initiative (GTRI) program.

  13. Hip Morphology Characterization

    PubMed Central

    Barrientos, Cristián; Diaz, Jorge; Brañes, Julian; Chaparro, Felipe; Barahona, Maximiliano; Salazar, Alfonso; Hinzpeter, Jaime

    2014-01-01

    Background: Femoroacetabular impingement (FAI) is the result of a mechanical conflict in the hip joint, and its diagnosis is based on clinical and radiological parameters. To our knowledge, there are no published studies describing the radiologic characteristics of FAI in Latin American populations. Purpose: To describe the radiological features associated with FAI in an asymptomatic Chilean population. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We prospectively recruited asymptomatic patients with no history or symptoms of hip pathology who underwent abdomen-pelvis computed tomography (CT) for a nonorthopaedic indication. The acetabular and femoral parameters related to FAI were measured. Results: We studied 101 subjects (202 hips) with a mean age of 36.8 ± 14.4 years. The mean center-edge angle was 39.4° ± 7.2°. The crossover sign was present in 34 cases (33.7%). The mean alpha angle was 49.7° ± 8.3°. Depending on the cut points chosen for FAI-related parameters, between 39.6% and 69.3% of an asymptomatic Chilean population were found to have morphological features related to FAI. Conclusion: Our findings suggest that the proposed pathological threshold values in the literature cannot be extrapolated to a Chilean population, and this must be taken into consideration when evaluating Latin American patients with hip pain. PMID:26535273

  14. Implications of the Utopia Gravity Anomaly for the Resurfacing of the Northern Plains of Mars

    NASA Technical Reports Server (NTRS)

    Banerdt, W. B.

    2004-01-01

    Whereas the surface units of the northern plain of Mars generally exhibit ages ranging from late Hesperian to Amazonian, interpretation of precise topographic measurements indicate that the age of the underlying "basement" is early Noachian, or almost as old as the southern highlands. This suggests that widespread but relatively superficial resurfacing has occurred throughout the northern plains since the end of early heavy bombardment. In this abstract I examine some of the possible implications of the subsurface structure inferred for the Utopia basin from gravity data on the nature of this resurfacing. The large, shallow, circular depression in Utopia Planitia has been identified as a huge impact basin, based on both geological evidence and detailed analysis of MOLA topography. Its diameter (approx. 3000 km) is equivalent to that of the Hellas basin, as is its inferred age (early Noachian). However, whereas Hellas is extremely deep with rough terrain and large slopes, the Utopia basin is a smooth, shallow, almost imperceptible bowl. Conversely, Utopia displays one of the largest (non-Tharsis-related) positive geoid anomalies on Mars, in contrast to a much more subdued negative anomaly over Hellas.

  15. Turn over split fascial flap - a refinement for resurfacing shin defect

    PubMed Central

    Bhattacharya, Visweswar; Agrawal, Neeraj K; Chaudhuri, Gaurab R; Barooah, Partha S; SK, Tripathi; Birendra, Rana; Bhattacharya, Siddhartha; Deka, Dhruva J

    2012-01-01

    Moderate size defects of the shin of tibia are frequently encountered following trauma and infection. They may be associated with or without a fracture. Such defects require resurfacing by a flap. Many different types of flaps have been described but most of them proved to be more bulky than desired. Although these procedures cover the defects successfully the results they produce are not aesthetically appropriate. The flap looks bulkier because the native subcutaneous tissue is thin over the shin and distal leg. Hence a search for a vascularized tissue of minimal bulk for suitable resurfacing was initiated. A turnover fascial flap fulfilled the requirement. Such a flap can be made thinner by splitting its distal part into two layers while maintaining a common vascular fascial pedicle with both the layers of the fascia. This allowed a larger surface area to be covered. Such refinement is based on the following parameters (a) fresh cadaveric dissection, (b) demonstration of live microcirculation individually in the superficial and deep layers of the deep fascia and (c) intraoperative flourescein study of the split fascial flap. The technique has been used in 5 cases over the upper and middle third of the shin of tibia. The split fascial flap was turned over and inset in the defect and covered with a split skin graft. The donor site was primarily closed. The functional and aesthetic results were highly satisfactory. The follow up of 18 months proved the durability and usefulness of the flap. PMID:23071906

  16. Early Attempts at Hip Arthroplasty

    PubMed Central

    Gomez, Pablo F; Morcuende, Jose A

    2005-01-01

    Over the last three centuries, treatment of hip arthritides has evolved from rudimentary surgery to modern total hip arthroplasty (THA), which is considered one of the most successful surgical interventions ever developed. We here review the history of the early hip arthroplasty procedures for hip arthritis that preceded Charley total hip arthroplasty. An evaluation of such past enterprises is relevant, and reminds us of the ephemeral nature of human industriousness, and how medical research and procedures are not isolated developments, but correlate to the social, economical, and cultural framework of their time. PMID:16089067

  17. Hip Arthroscopy: A Brief History.

    PubMed

    Kandil, Abdurrahman; Safran, Marc R

    2016-07-01

    Hip arthroscopy is a fast-growing and evolving field. Like knee and shoulder arthroscopy, hip arthroscopy began as a diagnostic procedure and then progressed to biopsy and resection of abnormalities. Subsequently, it has evolved to repair of various tissues and treatment of underlying causes. As the understanding of the hip joint and its associated pathophysiology grows, indications will continue to expand for this diagnostic and therapeutic modality. This article outlines the historic developments of hip arthroscopy, including advancements in instrumentation and techniques from the days of the first hip arthroscopies to the present day.

  18. Presence of corrosion products and hypersensitivity-associated reactions in periprosthetic tissue after aseptic loosening of total hip replacements with metal bearing surfaces.

    PubMed

    Huber, Monika; Reinisch, Georg; Trettenhahn, Günter; Zweymüller, Karl; Lintner, Felix

    2009-01-01

    Aseptic loosening of articular implants is frequently associated with tissue reactions to wear particles. Some patients, who had received metal-on-metal articulations, present early symptoms including persistent pain and implant failure. These symptoms raise the suspicion about the development of an immunological response. Furthermore, the generation of rare corrosion products in association with metallic implants has been observed. Corrosion products are known to enhance third-body wear and contribute to the loss of the implant. The purpose of this study was to investigate periprosthetic tissue containing solid corrosion products after aseptic loosening of second-generation metal-on-metal total hip replacements made of low-carbon cobalt-chromium-molybdenum alloy for the presence of immunologically determined tissue changes. Periprosthetic tissue of 11 cases containing uncommon solid deposits was investigated by light microscopy. In order to confirm the presence of corrosion products, additional methods including scanning electron microscopy (SEM) investigation, energy dispersive X-ray (EDX) and Fourier transform infrared microspectroscopy (FTIR) analysis were used. All investigated cases revealed solid chromium orthophosphate corrosion products as well as metallic wear particles to a various extent. Moreover, various intense tissue reactions characteristic of immune response were observed in all cases. The simultaneous presence of corrosion products and hypersensitivity-associated tissue reaction indicates that a relationship between corrosion development and implant-related hypersensitivity may exist. PMID:18725188

  19. Conus hip prosthesis.

    PubMed

    Wagner, H; Wagner, M

    2001-01-01

    50 years ago, prosthetic replacement of the hip joint ushered in a new epoch in orthopaedics. Total hip replacement made it possible to remove a severely diseased, painful hip and restore normal function and a normal quality of life to the afflicted patient. The early results of total hip replacement are almost all spectacular and hip replacement has become the most successful type of orthopaedic surgery. These good results using an approach that was technically relatively simple resulted in a temptation to implant prosthetic hip joints with ever increasing frequency in ever younger patients. This led to the emergence of new problems, which were not so clearly recognised at the outset: it emerged that the stability of prosthetic hip joints was of limited duration. This had the following consequence: If a total hip prosthesis is implanted in an elderly person whose remaining life-expectancy is shorter than the longevity of the prosthesis, hip replacement is a life-long solution. We can therefore say that, for a patient who has only 10 to 15 years left to live, their hip problem is solved by total hip replacement. For young people, who still have a long life expectancy in front of them, it is different. They will experience failure of the artificial joint and require further surgery. The commonest and most important type of failure in total hip prostheses is aseptic loosening, which is associated with resorption of bone at the site of the prosthesis. The cause of this phenomenon has only gradually been recognised in the course of the years. Initially, the unanimous opinion was that the methacrylate cement, used to fix the components of the prosthesis in the bone, was the definitive cause of aseptic loosening because fissures and fractures of the cement were almost always found during surgical revision of loosened joints. There was talk of "cement disease" and great efforts were made to improve the quality of the cement and the cementing technique. Moreover, even

  20. Total hip replacement in young adults with hip dysplasia

    PubMed Central

    2011-01-01

    Background and purpose Dysplasia of the hip increases the risk of secondary degenerative change and subsequent total hip replacement. Here we report on age at diagnosis of dysplasia, previous treatment, and quality of life for patients born after 1967 and registered with a total hip replacement due to dysplasia in the Norwegian Arthroplasty Register. We also used the medical records to validate the diagnosis reported by the orthopedic surgeon to the register. Methods Subjects born after January 1, 1967 and registered with a primary total hip replacement in the Norwegian Arthroplasty Register during the period 1987–2007 (n = 713) were included in the study. Data on hip symptoms and quality of life (EQ-5D) were collected through questionnaires. Elaborating information was retrieved from the medical records. Results 540 of 713 patients (76%) (corresponding to 634 hips) returned the questionnaires and consented for additional information to be retrieved from their medical records. Hip dysplasia accounted for 163 of 634 hip replacements (26%), 134 of which were in females (82%). Median age at time of diagnosis was 7.8 (0–39) years: 4.4 years for females and 22 years for males. After reviewing accessible medical records, the diagnosis of hip dysplasia was confirmed in 132 of 150 hips (88%). Interpretation One quarter of hip replacements performed in patients aged 40 or younger were due to an underlying hip dysplasia, which, in most cases, was diagnosed during late childhood. The dysplasia diagnosis reported to the register was correct for 88% of the hips. PMID:21434808

  1. Effect of high hip center on stress for dysplastic hip.

    PubMed

    Nie, Yong; Pei, Fuxing; Li, Zongming

    2014-07-01

    High hip center reconstruction has been advocated in treating deficient acetabulum. However, there is no consensus on the clinical outcome of this technique. In addition, it remains unclear to what extend this technique restores the normal hip biomechanics. The goal of this study was to investigate stress above the acetabular dome in response to a range of high hip center positioning for Crowe type I and II hip dysplasia. This study consisted of 2 main parts, radiologic and biomechanical. Pelvic radiographs of 18 patients were studied to determine the amount of displacement of the hip center in the superior direction compared with the normal side. Second, qualitative and quantitative changes in stress on cortical and trabecular bone in the region of the acetabular dome as a result of superior displacement of the hip center were analyzed with subject-specific finite element models. The results showed that the range of the hip center position in the superior direction for Crowe type I and II hip dysplasia was 0 to 15 mm above the contralateral femoral head center. When superior displacement of the hip center exceeded 5 mm above the anatomic hip center, cortical bone mass on the 2 thickest cross-sections above the acetabular dome decreased quickly and the stress value on posterolateral cortical bone was obviously lower than the normal level. This study showed that to restore the normal load above the acetabular dome, there is a limit of 5 mm above the anatomic hip center for high hip center acetabular reconstruction for Crowe type I and II hip dysplasia. PMID:24992059

  2. On the lack of commensurabilities in the mean motions of the satellites of Uranus and the resurfacing of Ariel

    NASA Technical Reports Server (NTRS)

    Peale, S. J.

    1987-01-01

    The lack of commensurabilites among the mean motion of the satellites of Uranus is investigated by determining the probabilities of capture into those orbital resonances which might be encountered as the satellite orbits expand differentially from tidal torques. An alternate to this is investigated to evaluate the conditions necessary to allow sufficient tidal heating of Ariel for the observed resurfacing.

  3. Extra-articular Snapping Hip

    PubMed Central

    2010-01-01

    Context: Snapping hip, or coxa saltans, is a vague term used to describe palpable or auditory snapping with hip movements. As increasing attention is paid to intra-articular hip pathologies such as acetabular labral tears, it is important to be able to identify and understand the extra-articular causes of snapping hip. Evidence Acquisition: The search terms snapping hip and coxa sultans were used in PubMed to locate suitable studies of any publication date (ending date, November 2008). Results: Extra-articular snapping may be caused laterally by the iliotibial band or anteriorly by the iliopsoas tendon. Snapping of the iliopsoas tendon usually requires contraction of the hip flexors and may be difficult to differentiate from intra-articular causes of snapping. Dynamic ultrasound can help detect abrupt tendon translation during movement, noninvasively supporting the diagnosis of extra-articular snapping hip. The majority of cases of snapping hip resolve with conservative treatment, which includes avoidance of aggravating activities, stretching, and anti-inflammatory medication. In recalcitrant cases, surgery to lengthen the iliotibial band or the iliopsoas tendon has produced symptom relief but may result in prolonged weakness. Conclusions: In treating active patients with snapping soft tissues around the hip, clinicians should recognize that the majority of cases resolve without surgical intervention, while being mindful of the potential for concomitant intra-articular and internal snapping hips. PMID:23015936

  4. Arthroscopic debridement and biological resurfacing of the glenoid in glenohumeral arthritis.

    PubMed

    de Beer, Joe F; Bhatia, Deepak N; van Rooyen, Karin S; Du Toit, Donald F

    2010-12-01

    The purpose of this study was to analyse the intermediate-term results of an arthroscopic procedure to debride and resurface the arthritic glenoid, in a middle-aged population, using an acellular human dermal scaffold. Between 2003 and 2005, thirty-two consecutive patients underwent an arthroscopic debridement and biological glenoid resurfacing for glenohumeral arthritis. The diagnoses included primary osteoarthrosis (28 patients), arthritis after arthroscopic reconstruction for anterior instability (1 patient) and inflammatory arthritis (3 patients). All shoulders were assessed clinically using the Constant and Murley score, and results graded according to Neer's criteria. Statistical analysis was performed to determine significant parameters and associations. A significant improvement (P < 0.0001) in each parameter of the subjective evaluation component (severity of pain, limitation in daily living and recreational activities) of the Constant score was observed. The Constant and Murley score increased significantly (P < 0.0001) from a median of 40 points (range 26-63) pre-operatively to 64.5 (range 19-84) at the final assessment. Overall, the procedure was considered as "successful outcome" in 23 patients (72%) and as a "failure" in 9 patients (28%). According to Neer's criteria, the result was categorized as excellent in 9 (28%), satisfactory in 14 (44%) and unsatisfactory in 9 (28%). Within the unsatisfactory group, there were five conversions to prosthetic arthroplasty. A standard magnetic resonance imaging was performed on 22 patients in the successful outcome group; glenoid cartilage was identified in 12 (thick in 5, intermediate in 1, thin in 6) and could not be identified in 10 patients (complete/incomplete loss in 5, technical difficulties in 5). Overall, five complications included transient axillary nerve paresis, foreign-body reaction to biological material, inter-layer dissociation, mild chronic non-specific synovitis and post-traumatic contusion

  5. Mixing of components from different manufacturers in total hip arthroplasty: prevalence and comparative outcomes

    PubMed Central

    Tucker, Keith; Pickford, Martin; Newell, Claire; Howard, Peter; Hunt, Linda P; Blom, Ashley W

    2015-01-01

    Background and purpose — There have recently been highly publicized examples of suboptimal outcomes with some newer implant designs used for total hip replacement. This has led to calls for tighter regulation. However, surgeons do not always adhere to the regulations already in place and often use implants from different manufacturers together to replace a hip, which is against the recommendations of the Medicines and Healthcare Products Regulatory Agency (MHRA) and the directions of the manufacturers. Patients and methods — We used data from the National Joint Registry of England and Wales (NJR) to investigate this practice. Results — Mixing of components was common, and we identified over 90,000 cases recorded between 2003 and 2013. In the majority of these cases (48,156), stems and heads from one manufacturer were mixed with polyethylene cemented cups from another manufacturer. When using a cemented stem and a polyethylene cup, mixing of stems from one manufacturer with cups from another was associated with a lower revision rate. At 8 years, the cumulative percentage of revisions was 1.9% (95% CI: 1.7–2.1) in the mixed group as compared to 2.4% (2.3–2.5) in the matched group (p = 0.001). Mixing of heads from one manufacturer with stems from another was associated with a higher revision rate (p < 0.001). In hip replacements with ceramic-on-ceramic or metal-on-metal bearings, mixing of stems, heads, and cups from different manufacturers was associated with similar revision rates (p > 0.05). Interpretation — Mixing of components from different manufacturers is a common practice, despite the fact that it goes against regulatory guidance. However, it is not associated with increased revision rates unless heads and stems from different manufacturers are used together. PMID:26201845

  6. Current Laser Resurfacing Technologies: A Review that Delves Beneath the Surface

    PubMed Central

    Preissig, Jason; Hamilton, Kristy; Markus, Ramsey

    2012-01-01

    Numerous laser platforms exist that rejuvenate the skin by resurfacing its upper layers. In varying degrees, these lasers improve the appearance of lentigines and rhytides, eliminate photoaging, soften scarring due to acne and other causes, and treat dyspigmentation. Five major classes of dermatologic lasers are currently in common use: ablative and nonablative lasers in both fractionated and unfractionated forms as well as radiofrequency technologies. The gentler nonablative lasers allow for quicker healing, whereas harsher ablative lasers tend to be more effective. Fractionating either laser distributes the effect, increasing the number of treatments but minimizing downtime and complications. In this review article, the authors seek to inform surgeons about the current laser platforms available, clarify the differences between them, and thereby facilitate the identification of the most appropriate laser for their practice. PMID:23904818

  7. Secondary Patellar Resurfacing after Primary Bicondylar Knee Arthroplasty did Not Meet Patients' Expectations.

    PubMed

    Correia, João; Sieder, Marc; Kendoff, Daniel; Citak, Mustafa; Gehrke, Thorsten; Klauser, Wolfgang; Haasper, Carl

    2012-01-01

    Secondary patella resurfacing is a controversial procedure which is applied in patients with anterior knee pain after a bicondylar knee arthroplasty (with unresurfaced patella). A group of 46 patients were submitted to this procedure and their satisfaction, range of motion and pain improvement was evaluated. 52.2% of the patients were satisfied with the procedure, with an improvement in pain (Visual Analogue Scale) of 65% and an improvement in range of motion in 56,5%, with roundabout half of the patients having no resolution to their complaints. Whilst an improvement was not achieved in all patients, as it was initially hypothesised, this procedure should be considered when a revision knee arthroplasty is performed with an unresurfaced patella.

  8. Secondary Patellar Resurfacing after Primary Bicondylar Knee Arthroplasty did Not Meet Patients’ Expectations

    PubMed Central

    Correia, João; Sieder, Marc; Kendoff, Daniel; Citak, Mustafa; Gehrke, Thorsten; Klauser, Wolfgang; Haasper, Carl

    2012-01-01

    Secondary patella resurfacing is a controversial procedure which is applied in patients with anterior knee pain after a bicondylar knee arthroplasty (with unresurfaced patella). A group of 46 patients were submitted to this procedure and their satisfaction, range of motion and pain improvement was evaluated. 52.2% of the patients were satisfied with the procedure, with an improvement in pain (Visual Analogue Scale) of 65% and an improvement in range of motion in 56,5%, with roundabout half of the patients having no resolution to their complaints. Whilst an improvement was not achieved in all patients, as it was initially hypothesised, this procedure should be considered when a revision knee arthroplasty is performed with an unresurfaced patella. PMID:23002412

  9. 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... 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)...

  10. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint femoral (hemi-hip) metallic cemented or... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  11. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint femoral (hemi-hip) metallic cemented or... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  12. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint femoral (hemi-hip) metallic cemented or... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  13. 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... 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)...

  14. 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... 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)...

  15. 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)...

  16. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint femoral (hemi-hip) metallic cemented or... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  17. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint femoral (hemi-hip) metallic cemented or... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  18. 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... 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)...

  19. Evidence for Recent Resurfacing of the Binary Kuiper Belt Object 1997 CS29

    NASA Astrophysics Data System (ADS)

    Rabinowitz, David L.; Schaefer, B.; Schaefer, M.; Tourtellotte, S.

    2009-09-01

    At solar phase angles less than 0.1 deg, some icy bodies exhibit an extraordinary opposition surge, suddenly brightening by 50% at near zero phase. Verbiscer et al [1] observed this phenomena for the icy Galilean satellites Mimas, Enceladus, Tethys, Dione, and Rhea and suggest the surge results from the light-scattering properties of freshly resurfaced icy regoliths. Buratti et al [2] and Earle et al [3] observed a similarly sharp opposition surge on Neptune's icy satellite Triton, which is known to have active cryovolcanoes. Here we examine the solar phase curves of 9 Trans-Neptunian Objects that we have measured at phase angles smaller than 0.1 deg (Rabinowitz et al [4], Schaefer et al [5]), including previously unpublished observations 1997 CS29 and 2005 UJ438. This sample includes hot and cold classical Kuiper-Belt objects, Plutinos, Centaurs, and three binary TNOs. Of all these targets, only 1997 CS29 has a sharp surge at near zero phase, and a nearly flat phase curve at large angles. Since this target is also a binary with an unusually large and close companion [6], we suggest that both 1997 CS29 and its companion have been resurfaced by each other's impact ejecta via the mechanism proposed by Stern [7], with fresh surface material producing the opposition spike. [1] Verbiscer, A., et al. 2007, Science, 315, 815; [2] Buratti, B. et al. 2007, Workshop on Ices, Oceans, and Fire: Satellites of the Outer Solar System, Boulder Colorado; [3] Earle, D., et al. 2008, BAAS, 40, 480; [4] Rabinowitz, D. et al. 2007, AJ, 133, 26; [5] Schaefer, B., et al. 2009, AJ, 137, 129; [6] Stephens, D. & Knoll, K. 2006, AJ, 131,1142;[7] Stern, S. A. 2009, Icarus, 199, 571.

  20. Congenital Dislocation of the Hip

    PubMed Central

    Premi, J. M.

    1976-01-01

    The implications of a diagnosis of congenital dislocation of the hip and the importance of the role of the family physician in early detection and treatment are identified. A review of the salient clinical features of congenital dislocation of the hip is undertaken. The results of a survey carried out in the author's practice on an unusual incidence of congenital dislocated hip are reviewed. PMID:21308053

  1. Heterotopic ossification after hip arthroscopy

    PubMed Central

    Amar, Eyal; Sharfman, Zachary T.; Rath, Ehud

    2015-01-01

    Heterotopic ossification (HO) after hip arthroscopy is the abnormal formation of mature lamellar bone within extra skeletal soft tissues. HO may lead to pain, impaired range of motion and possibly revision surgery. There has been a substantial amount of recent research on the pathophysiology, prophylaxis and treatment of HO associated with open and arthroscopic hip surgery. This article reviews the literature on the aforementioned topics with a focus on their application in hip arthroscopy. PMID:27011859

  2. Capsular Management in Hip Arthroscopy.

    PubMed

    Harris, Joshua D

    2016-07-01

    The hip capsule is a highly complex anatomic structure, which influences normal hip motion and biomechanics. A dynamic stabilizing capsular contribution exists in the iliocapsularis and gluteus minimus, among other musculotendinous structures crossing the joint. Variable types and sizes of capsulotomy are necessary to sufficiently visualize and address the bony and soft tissue pathologic source of symptoms. Unrepaired capsulotomies may leave the hip significantly unstable to variable degrees. Capsular closure is a necessary part of a comprehensive arthroscopic hip preservation procedure. Greater titration of the degree of plication may be performed for patients with risk factors for postoperative instability. PMID:27343391

  3. Developmental Dislocation (Dysplasia) of the Hip (DDH)

    MedlinePlus

    ... developmental dysplasia (dislocation) of the hip (DDH), the hip joint has not formed normally. The ball is loose ... be taken to provide detailed pictures of the hip joint. Treatment When DDH is detected at birth, it ...

  4. The digital global geologic map of Mars: chronostratigraphic ages, topographic and crater morphologic characteristics, and updated resurfacing history

    USGS Publications Warehouse

    Tanaka, K.L.; Robbins, S.J.; Fortezzo, C.M.; Skinner, J.A.; Hare, T.M.

    2014-01-01

    A new global geologic map of Mars has been completed in a digital, geographic information system (GIS) format using geospatially controlled altimetry and image data sets. The map reconstructs the geologic history of Mars, which includes many new findings collated in the quarter century since the previous, Viking-based global maps were published, as well as other discoveries that were made during the course of the mapping using new data sets. The technical approach enabled consistent and regulated mapping that is appropriate not only for the map's 1:20,000,000 scale but also for its widespread use by diverse audiences. Each geologic unit outcrop includes basic attributes regarding identity, location, area, crater densities, and chronostratigraphic age. In turn, units are grouped by geographic and lithologic types, which provide synoptic global views of material ages and resurfacing character for the Noachian, Hesperian, and Amazonian periods. As a consequence of more precise and better quality topographic and morphologic data and more complete crater-density dating, our statistical comparisons identify significant refinements for how Martian geologic terrains are characterized. Unit groups show trends in mean elevation and slope that relate to geographic occurrence and geologic origin. In comparison with the previous global geologic map series based on Viking data, the new mapping consists of half the number of units due to simpler, more conservative and globally based approaches to discriminating units. In particular, Noachian highland surfaces overall have high percentages of their areas now dated as an epoch older than in the Viking mapping. Minimally eroded (i.e., pristine) impact craters ≥3 km in diameter occur in greater proportion on Hesperian surfaces. This observation contrasts with a deficit of similarly sized craters on heavily cratered and otherwise degraded Noachian terrain as well as on young Amazonian surfaces. We interpret these as reflecting the

  5. Hip dysplasia in the skeletally mature patient.

    PubMed

    Goldstein, Rachel Y; Kaye, Ian David; Slover, James; Feldman, David

    2014-01-01

    Abnormal hip development causes one-quarter to one-half of all hip disease. Dysplastic hips typically share characteristic anatomic abnormalities. The dysplastic acetabulum is typically shallow, lateralized, and anteverted with insufficient coverage anteriorly, superiorly, and laterally. The dysplastic proximal femur has a small femoral head with excessive femoral neck anteversion and a short neck with an increased neck shaft angle. These characteristic changes result in intraarticular pathology leading to hip arthritis. A variety of treatment options exist based on the degree of dysplasia and the amount of concomitant hip arthritis. Treatment options include hip arthroscopy, acetabular or femoral osteotomies, hip arthrodesis, and total hip arthroplasty. PMID:25150325

  6. A Randomized controlled trial comparing patellar retention versus patellar resurfacing in primary total knee arthroplasty: 5–10 year follow-up

    PubMed Central

    2012-01-01

    Background The primary purpose of this randomized controlled trial (RCT) was to compare knee-specific outcomes (stiffness, pain, function) between patellar retention and resurfacing up to 10 years after primary total knee arthroplasty (TKA). Secondarily, we compared re-operation rates. Methods 38 subjects with non-inflammatory arthritis were randomized at primary TKA surgery to receive patellar resurfacing (n = 21; Resurfaced group) or to retain their native patella (n = 17; Non-resurfaced group). Evaluations were performed preoperatively, one, five and 10 years postoperatively by an evaluator who was blinded to group allocation. Self-reported knee-specific stiffness, pain and function, the primary outcomes, were measured by the Western Ontario McMaster Osteoarthritis Index (WOMAC). Revision rate was determined at each evaluation and through hospital record review. Results 30 (88%) and 23 (72%) of available subjects completed the five and 10-year review respectively. Knee-specific scores continued to improve for both groups over the 10-years, despite diminishing overall health with no significant group differences seen. All revisions occurred within five years of surgery (three Non-resurfaced subjects; one Resurfaced subject) (p = 0.31). Two revisions in the Non-resurfaced group were due to persistent anterior knee pain. Conclusions We found no differences in knee-specific results between groups at 5–10 years postoperatively. The Non-resurfaced group had two revisions due to anterior knee pain similar to rates reported in other studies. Knee-specific results provide useful postoperative information and should be used in future studies comparing patellar management strategies. ClinicalTrials.gov identifier NCT01500252 PMID:22676495

  7. Hip-Hop Education Resources

    ERIC Educational Resources Information Center

    Hall, Marcella Runell

    2009-01-01

    Hip-hop music and culture are often cited as being public pedagogy, meaning the music itself has intrinsic educational value. Non-profit organizations and individual educators have graciously taken the lead in utilizing hip-hop to educate. As the academy continues to debate its effectiveness, teachers and community organizers are moving forward.…

  8. Feasibility of asymmetric flow field-flow fractionation coupled to ICP-MS for the characterization of wear metal particles and metalloproteins in biofluids from hip replacement patients.

    PubMed

    Loeschner, Katrin; Harrington, Chris F; Kearney, Jacque-Lucca; Langton, David J; Larsen, Erik H

    2015-06-01

    Hip replacements are used to improve the quality of life of people with orthopaedic conditions, but the use of metal-on-metal (MoM) arthroplasty has led to poor outcomes for some patients. These problems are related to the generation of micro- to nanosized metal wear particles containing Cr, Co or other elements, but the current analytical methods used to investigate the processes involved do not provide sufficient information to understand the size or composition of the wear particles generated in vivo. In this qualitative feasibility study, asymmetric flow field-flow fractionation (AF(4)) coupled with inductively coupled plasma mass spectrometry (ICP-MS) was used to investigate metal protein binding and the size and composition of wear metal particles present in serum and hip aspirates from MoM hip replacement patients. A well-established HPLC anion exchange chromatography (AEC) separation system coupled to ICP-MS was used to confirm the metal-protein associations in the serum samples. Off-line single particle ICP-MS (spICP-MS) analysis was used to confirm the approximate size distribution indicated by AF(4) of the wear particles in hip aspirates. In the serum samples, AF(4) -ICP-MS suggested that Cr was associated with transferrin (Tf) and Co with albumin (Alb) and an unidentified species; AEC-ICP-MS confirmed these associations and also indicated an association of Cr with Alb. In the hip aspirate sample, AF(4)-ICP-MS suggested that Cr was associated with Alb and Tf and that Co was associated with Alb and two unidentified compounds; AEC analysis confirmed the Cr results and the association of Co with Alb and a second compound. Enzymatic digestion of the hip aspirate sample, followed by separation using AF(4) with detection by UV absorption (280 nm), multi-angle light scattering and ICP-MS, suggested that the sizes of the Cr-, Co- and Mo-containing wear particles in a hip aspirate sample were in the range 40-150 nm. Off-line spICP-MS was used to confirm these

  9. Immunohistochemical evaluation of the heat shock response to nonablative fractional resurfacing

    NASA Astrophysics Data System (ADS)

    Hantash, Basil M.; Bedi, Vikramaditya P.; Struck, Steven K.; Chan, Kin F.

    2010-11-01

    Despite the emergence of nonablative fractional resurfacing (NFR) as a new therapeutic modality for skin photoaging, little is known about the molecular events that underlie the heat shock response to different treatment parameters. Human subjects are treated with a scanned 1550-nm fractional laser at pulse energies spanning 6 to 40 mJ and a 140-μm spot size. The heat shock response is assessed immunohistochemically immediately through 7 days posttreatment. At the immediately posttreatment time point, we observe subepidermal clefting in most sections. The basal epidermis and dermal zones of sparing are both found to express HSP47, but not HSP72. By day 1, expression of HSP72 is detected throughout the epidermis, while that of HSP47 remains restricted to the basal layer. Both proteins are detected surrounding the dermal portion of the microscopic treatment zone (MTZ). This pattern of expression persists through day 7 post-NFR, although neither protein is found within the MTZ. Immediately posttreatment, the mean collagen denaturation zone width is 50 μm at 6 mJ, increasing to 202 μm at 40 mJ. The zone of cell death exceeds the denaturation zone by 19 to 55% over this pulse energy range. The two zones converge by day 7 posttreatment.

  10. Tsunami waves extensively resurfaced the shorelines of an early Martian ocean.

    PubMed

    Rodriguez, J Alexis P; Fairén, Alberto G; Tanaka, Kenneth L; Zarroca, Mario; Linares, Rogelio; Platz, Thomas; Komatsu, Goro; Miyamoto, Hideaki; Kargel, Jeffrey S; Yan, Jianguo; Gulick, Virginia; Higuchi, Kana; Baker, Victor R; Glines, Natalie

    2016-05-19

    It has been proposed that ~3.4 billion years ago an ocean fed by enormous catastrophic floods covered most of the Martian northern lowlands. However, a persistent problem with this hypothesis is the lack of definitive paleoshoreline features. Here, based on geomorphic and thermal image mapping in the circum-Chryse and northwestern Arabia Terra regions of the northern plains, in combination with numerical analyses, we show evidence for two enormous tsunami events possibly triggered by bolide impacts, resulting in craters ~30 km in diameter and occurring perhaps a few million years apart. The tsunamis produced widespread littoral landforms, including run-up water-ice-rich and bouldery lobes, which extended tens to hundreds of kilometers over gently sloping plains and boundary cratered highlands, as well as backwash channels where wave retreat occurred on highland-boundary surfaces. The ice-rich lobes formed in association with the younger tsunami, showing that their emplacement took place following a transition into a colder global climatic regime that occurred after the older tsunami event. We conclude that, on early Mars, tsunamis played a major role in generating and resurfacing coastal terrains.

  11. Mercury crater statistics from MESSENGER flybys: Implications for stratigraphy and resurfacing history

    NASA Astrophysics Data System (ADS)

    Strom, Robert G.; Banks, Maria E.; Chapman, Clark R.; Fassett, Caleb I.; Forde, Jeffrey A.; Head, James W.; Merline, William J.; Prockter, Louise M.; Solomon, Sean C.

    2011-12-01

    The primary crater population on Mercury has been modified by volcanism and secondary craters. Two phases of volcanism are recognized. One volcanic episode that produced widespread intercrater plains occurred during the period of the Late Heavy Bombardment and markedly altered the surface in many areas. The second episode is typified by the smooth plains interior and exterior to the Caloris basin, both of which have a different crater size-frequency distribution than the intercrater plains, consistent with a cratering record dominated by a younger population of impactors. These two phases may have overlapped as parts of a continuous period of volcanism during which the volcanic flux tended to decrease with time. The youngest age of smooth plains volcanism cannot yet be determined, but at least small expanses of plains are substantially younger than the plains associated with the Caloris basin. The spatial and temporal variations of volcanic resurfacing events can be used to reconstruct Mercury's geologic history from images and compositional and topographic data to be acquired during the orbital phase of the MESSENGER mission.

  12. Evidence and considerations in the application of chemical peels in skin disorders and aesthetic resurfacing.

    PubMed

    Rendon, Marta I; Berson, Diane S; Cohen, Joel L; Roberts, Wendy E; Starker, Isaac; Wang, Beatrice

    2010-07-01

    Chemical peeling is a popular, relatively inexpensive, and generally safe method for treatment of some skin disorders and to refresh and rejuvenate skin. This article focuses on chemical peels and their use in routine clinical practice. Chemical peels are classified by the depth of action into superficial, medium, and deep peels. The depth of the peel is correlated with clinical changes, with the greatest change achieved by deep peels. However, the depth is also associated with longer healing times and the potential for complications. A wide variety of peels are available, utilizing various topical agents and concentrations, including a recent salicylic acid derivative, beta-lipohydroxy acid, which has properties that may expand the clinical use of peels. Superficial peels, penetrating only the epidermis, can be used to enhance treatment for a variety of conditions, including acne, melasma, dyschromias, photodamage, and actinic keratoses. Medium-depth peels, penetrating to the papillary dermis, may be used for dyschromia, multiple solar keratoses, superficial scars, and pigmentary disorders. Deep peels, affecting reticular dermis, may be used for severe photoaging, deep wrinkles, or scars. Peels can be combined with other in-office facial resurfacing techniques to optimize outcomes and enhance patient satisfaction and allow clinicians to tailor the treatment to individual patient needs. Successful outcomes are based on a careful patient selection as well as appropriate use of specific peeling agents. Used properly, the chemical peel has the potential to fill an important therapeutic need in the dermatologist's and plastic surgeon's armamentarium. PMID:20725555

  13. Evidence and Considerations in the Application of Chemical Peels in Skin Disorders and Aesthetic Resurfacing

    PubMed Central

    Berson, Diane S.; Cohen, Joel L.; Roberts, Wendy E.; Starker, Isaac; Wang, Beatrice

    2010-01-01

    Chemical peeling is a popular, relatively inexpensive, and generally safe method for treatment of some skin disorders and to refresh and rejuvenate skin. This article focuses on chemical peels and their use in routine clinical practice. Chemical peels are classified by the depth of action into superficial, medium, and deep peels. The depth of the peel is correlated with clinical changes, with the greatest change achieved by deep peels. However, the depth is also associated with longer healing times and the potential for complications. A wide variety of peels are available, utilizing various topical agents and concentrations, including a recent salicylic acid derivative, β-lipohydroxy acid, which has properties that may expand the clinical use of peels. Superficial peels, penetrating only the epidermis, can be used to enhance treatment for a variety of conditions, including acne, melasma, dyschromias, photodamage, and actinic keratoses. Medium-depth peels, penetrating to the papillary dermis, may be used for dyschromia, multiple solar keratoses, superficial scars, and pigmentary disorders. Deep peels, affecting reticular dermis, may be used for severe photoaging, deep wrinkles, or scars. Peels can be combined with other in-office facial resurfacing techniques to optimize outcomes and enhance patient satisfaction and allow clinicians to tailor the treatment to individual patient needs. Successful outcomes are based on a careful patient selection as well as appropriate use of specific peeling agents. Used properly, the chemical peel has the potential to fill an important therapeutic need in the dermatologist's and plastic surgeon's armamentarium. PMID:20725555

  14. Tsunami waves extensively resurfaced the shorelines of an early Martian ocean

    NASA Astrophysics Data System (ADS)

    Rodriguez, J. Alexis P.; Fairén, Alberto G.; Tanaka, Kenneth L.; Zarroca, Mario; Linares, Rogelio; Platz, Thomas; Komatsu, Goro; Miyamoto, Hideaki; Kargel, Jeffrey S.; Yan, Jianguo; Gulick, Virginia; Higuchi, Kana; Baker, Victor R.; Glines, Natalie

    2016-05-01

    It has been proposed that ~3.4 billion years ago an ocean fed by enormous catastrophic floods covered most of the Martian northern lowlands. However, a persistent problem with this hypothesis is the lack of definitive paleoshoreline features. Here, based on geomorphic and thermal image mapping in the circum-Chryse and northwestern Arabia Terra regions of the northern plains, in combination with numerical analyses, we show evidence for two enormous tsunami events possibly triggered by bolide impacts, resulting in craters ~30 km in diameter and occurring perhaps a few million years apart. The tsunamis produced widespread littoral landforms, including run-up water-ice-rich and bouldery lobes, which extended tens to hundreds of kilometers over gently sloping plains and boundary cratered highlands, as well as backwash channels where wave retreat occurred on highland-boundary surfaces. The ice-rich lobes formed in association with the younger tsunami, showing that their emplacement took place following a transition into a colder global climatic regime that occurred after the older tsunami event. We conclude that, on early Mars, tsunamis played a major role in generating and resurfacing coastal terrains.

  15. Tsunami waves extensively resurfaced the shorelines of an early Martian ocean.

    PubMed

    Rodriguez, J Alexis P; Fairén, Alberto G; Tanaka, Kenneth L; Zarroca, Mario; Linares, Rogelio; Platz, Thomas; Komatsu, Goro; Miyamoto, Hideaki; Kargel, Jeffrey S; Yan, Jianguo; Gulick, Virginia; Higuchi, Kana; Baker, Victor R; Glines, Natalie

    2016-01-01

    It has been proposed that ~3.4 billion years ago an ocean fed by enormous catastrophic floods covered most of the Martian northern lowlands. However, a persistent problem with this hypothesis is the lack of definitive paleoshoreline features. Here, based on geomorphic and thermal image mapping in the circum-Chryse and northwestern Arabia Terra regions of the northern plains, in combination with numerical analyses, we show evidence for two enormous tsunami events possibly triggered by bolide impacts, resulting in craters ~30 km in diameter and occurring perhaps a few million years apart. The tsunamis produced widespread littoral landforms, including run-up water-ice-rich and bouldery lobes, which extended tens to hundreds of kilometers over gently sloping plains and boundary cratered highlands, as well as backwash channels where wave retreat occurred on highland-boundary surfaces. The ice-rich lobes formed in association with the younger tsunami, showing that their emplacement took place following a transition into a colder global climatic regime that occurred after the older tsunami event. We conclude that, on early Mars, tsunamis played a major role in generating and resurfacing coastal terrains. PMID:27196957

  16. Dust levitation as a major resurfacing process on the surface of a saturnian icy satellite, Atlas

    NASA Astrophysics Data System (ADS)

    Hirata, Naoyuki; Miyamoto, Hideaki

    2012-07-01

    A small inner satellite of Saturn, Atlas, has an enigmatic saucer-like shape explained by an accumulation of particles from A-ring of Saturn. However, its unusual smooth surface remains unexplained. Gardening through continuous particle impact events cannot be a unique explanation for the smoothness, because Prometheus does not exhibit a similar surface, though it too would have experienced a similar bombardment. Here, a detailed investigation using close-up images of Atlas reveals the surface to be (1) covered by fine particles (i.e., probably as small as several tens of micrometers); (2) mostly void of impact craters (i.e., only one has been thus far identified); and (3) continuously smooth, even between the equatorial ridge and the undulating polar region. These findings imply that some sort of crater-erasing process has been active on the surface of Atlas. From electro-static analyses, we propose that the upper-most layer of the fine particles can become electro-statically unstable and migrate as a result of dust levitation, which resulted in erasing craters on the surface of Atlas. If true, Atlas would represent the first recognized body where resurfacing is dominated by dust levitation.

  17. Tsunami waves extensively resurfaced the shorelines of an early Martian ocean

    PubMed Central

    Rodriguez, J. Alexis P.; Fairén, Alberto G.; Tanaka, Kenneth L.; Zarroca, Mario; Linares, Rogelio; Platz, Thomas; Komatsu, Goro; Miyamoto, Hideaki; Kargel, Jeffrey S.; Yan, Jianguo; Gulick, Virginia; Higuchi, Kana; Baker, Victor R.; Glines, Natalie

    2016-01-01

    It has been proposed that ~3.4 billion years ago an ocean fed by enormous catastrophic floods covered most of the Martian northern lowlands. However, a persistent problem with this hypothesis is the lack of definitive paleoshoreline features. Here, based on geomorphic and thermal image mapping in the circum-Chryse and northwestern Arabia Terra regions of the northern plains, in combination with numerical analyses, we show evidence for two enormous tsunami events possibly triggered by bolide impacts, resulting in craters ~30 km in diameter and occurring perhaps a few million years apart. The tsunamis produced widespread littoral landforms, including run-up water-ice-rich and bouldery lobes, which extended tens to hundreds of kilometers over gently sloping plains and boundary cratered highlands, as well as backwash channels where wave retreat occurred on highland-boundary surfaces. The ice-rich lobes formed in association with the younger tsunami, showing that their emplacement took place following a transition into a colder global climatic regime that occurred after the older tsunami event. We conclude that, on early Mars, tsunamis played a major role in generating and resurfacing coastal terrains. PMID:27196957

  18. Influence of Hip Joint Position on Muscle Activity during Prone Hip Extension with Knee Flexion

    PubMed Central

    Suehiro, Tadanobu; Mizutani, Masatoshi; Okamoto, Mitsuhisa; Ishida, Hiroshi; Kobara, Kenichi; Fujita, Daisuke; Osaka, Hiroshi; Takahashi, Hisashi; Watanabe, Susumu

    2014-01-01

    [Purpose] This study investigated the selective activation of the gluteus maximus during a prone hip extension with knee flexion exercise, with the hip joint in different positions. [Subjects] The subjects were 21 healthy, male volunteers. [Methods] Activities of the right gluteus maximus, right hamstrings, bilateral lumbar erector spinae, and bilateral lumbar multifidus were measured using surface electromyography during a prone hip extension with knee flexion exercise. Measurements were made with the hip joint in each of 3 positions: (1) a neutral hip joint position, (2) an abduction hip joint position, and (3) an abduction with external rotation hip joint position. [Results] Gluteus maximus activity was significantly higher when the hip was in the abduction with external rotation hip joint position than when it was in the neutral hip joint and abduction hip joint positions. Gluteus maximus activity was also significantly higher in the abduction hip joint position than in the neutral hip joint position. Hamstring activity was significantly lower when the hip was in the abduction with external rotation hip joint position than when it was in the neutral hip joint and abduction hip joint positions. [Conclusion] Abduction and external rotation of the hip during prone hip extension with knee flexion exercise selectively activates the gluteus maximus. PMID:25540492

  19. Fracture After Total Hip Replacement

    MedlinePlus

    ... er Total Hip Replacement cont. • Dislocation • Limb length inequality • Poor fracture healing • Repeat fracture • Lack of in- ... Surgeons (AAOS). To learn more about your orthopaedic health, please visit orthoinfo.org. Page ( 5 ) AAOS does ...

  20. The tribological behaviour of different clearance MOM hip joints with lubricants of physiological viscosities.

    PubMed

    Hu, X Q; Wood, R J K; Taylor, A; Tuke, M A

    2011-11-01

    Clearance is one of the most influential parameters on the tribological performance of metal-on-metal (MOM) hip joints and its selection is a subject of considerable debate. The objective of this paper is to study the lubrication behaviour of different clearances for MOM hip joints within the range of human physiological and pathological fluid viscosities. The frictional torques developed by MOM hip joints with a 50 mm diameter were measured for both virgin surfaces and during a wear simulator test. Joints were manufactured with three different diametral clearances: 20, 100, and 200 microm. The fluid used for the friction measurements which contained different ratios of 25 percent newborn calf serum and carboxymethyl cellulose (CMC) with the obtained viscosities values ranging from 0.001 to 0.71 Pa s. The obtained results indicate that the frictional torque for the 20 microm clearance joint remains high over the whole range of the viscosity values. The frictional torque of the 100 microm clearance joint was low for the very low viscosity (0.001 Pa s) lubricant, but increased with increasing viscosity value. The frictional torque of the 200 microm clearance joint was high at very low viscosity levels, however, it reduced with increasing viscosity. It is concluded that a smaller clearance level can enhance the formation of an elastohydrodynamic lubrication (EHL) film, but this is at the cost of preventing fluid recovery between the bearing surfaces during the unloaded phase of walking. Larger clearance bearings allow a better recovery of lubricant during the unloaded phase, which is necessary for higher viscosity lubricants. The selection of the clearance value should therefore consider both the formation of the EHL film and the fluid recovery as a function of the physiological viscosity in order to get an optimal tribological performance for MOM hip joints. The application of either 25 per cent bovine serum or water in existing in vitro tribological study should

  1. The hip in cerebral palsy.

    PubMed

    Bleck, E E

    1980-01-01

    Orthopedic surgery can alleviate the hip flexion, adduction, and medial rotation deformities of the hip and improve the function and appearance of gait. To accomplish this, however, careful examination and prudence in the operative procedure to avoid overdoing and overcorrecting are important. Orthopedic surgery can prevent subluxation and dislocation of the hip before the age of seven years, and consequently repetitive radiographic examinations of the hip in children who have spastic paralysis of the hip musculature should be a routine procedure. Subluxation and dislocation of the hip, when established, can be successfully treated with orthopedic surgical procedures. Physicians must keep in mind that the spastic paralysis of cerebral palsy originates in the brain, and therefore the spasticity cannot be eliminated. The best that can be done is to weaken or remove some muscles as deforming forces and to achieve compromises for continued function. The goal should be optimal independence for the child and adolescent during development, and freedom from pain with deteriorating function due to degenerative arthritis in the adult. PMID:7360505

  2. DYSPLASIA OF HIP DEVELOPMENT: UPDATE

    PubMed Central

    Guarniero, Roberto

    2015-01-01

    The term “developmental dysplasia of the hip” (DDH) includes a wide spectrum of abnormalities that affect the hip during its growth, ranging from dysplasia to joint dislocation and going through different degrees of coxofemoral subluxation. The incidence of DDH is variable, and depends on a number of factors, including geographical location. Approximately one in 1,000 newborn infants may present hip dislocation and around 10 in 1,000 present hip instability. Brazil has an incidence of five per 1,000 in terms of findings of a positive Ortolani sign, which is the early clinical sign for detecting the disorder. The risk factors for DDH include: female sex, white skin color, primiparity, young mother, breech presentation at birth, family history, oligohydramnios, newborns with greater weight and height, and deformities of the feet or spine. Hip examinations should be routine for newborns, and should be emphasized in maternity units. Among newborns and infants, the diagnosis of DDH is preeminently clinical and is made using the Ortolani and Barlow maneuvers. Conventional radiography is of limited value for confirming the diagnosis of DDH among newborns, and ultrasound of the hip is the ideal examination. The treatment of DDH is challenging, both for pediatric orthopedists and for general practitioners. The objectives of the treatment include diagnosis as early as possible, joint reduction and stabilization of the hip in a secure position. Classically, treatment options are divided according to different age groups, at the time of diagnosis. PMID:27022528

  3. The increase in cobalt release in metal-on-polyethylene hip bearings in tests with third body abrasives

    PubMed Central

    de Villiers, Danielle; Traynor, Alison; Collins, Simon N; Shelton, Julia C

    2015-01-01

    Hypersensitivity reactions in patients receiving metal-on-metal hip replacements have been attributed to corrosion products as observed by elevated cobalt and chromium ions in the blood. Although the majority of cases are reported in metal-on-metal, incidences of these reactions have been reported in the metal-on-polyethylene patient population. To date, no in vitro study has considered cobalt release for this bearing combination. This study considered four 28 mm and seven 52 mm diameter metal-on-polyethylene bearings tested following ISO standard hip simulator conditions as well as under established abrasive conditions. These tests showed measurable cobalt in all bearings under standard conditions. Cobalt release, as well as polyethylene wear, increased with diameter, increasing from 52 to 255 ppb. The introduction of bone cement particles into the articulation doubled polyethylene wear and cobalt release while alumina particles produced significant damage on the heads demonstrated by cobalt levels of 70,700 ppb and an increased polyethylene wear from a mean value of 9–160 mm3/mc. Cobalt release was indicative of head damage and correlated with polyethylene wear at the next gravimetric interval. The removal of third body particles resulted in continued elevated cobalt levels in the 52 mm diameter bearings tested with alumina compared to standard conditions but the bearings tested with bone cement particles returned to standard levels. The polyethylene wear in the bone cement tested bearings also recovered to standard levels, although the alumina tested bearings continued to wear at a higher rate of 475 mm3/mc. Cobalt release was shown to occur in metal-on-polyethylene bearings indicating damage to the metal head resulting in increased polyethylene wear. While large diameter metal-on-polyethylene bearings may provide an increased range of motion and a reduced dislocation risk, increased levels of cobalt are likely to be released and this needs to be

  4. Review on squeaking hips

    PubMed Central

    Levy, Yadin David; Munir, Selin; Donohoo, Shane; Walter, William Lindsay

    2015-01-01

    Squeaking is a well-recognized complication for hard-on-hard bearings. The nature of squeaking is not yet completely understood however it is considered a multifactorial phenomenon. Patient, implant, and surgical factors play a role in squeaking. It is believed that mechanisms damaging the fluid film lubrication in which these bearings function optimally have a critical role. Such mechanisms include edge loading, stripe wear, impingement, third body particles and ceramic fracture. The resonance of metallic parts can produce noise in the human audible range hence the implant metallurgic composition and design may play a role. Implant positioning can facilitate impingement and edge loading enhancing the occurrence of squeaking. The recent introduction of large heads (> 36 mm) 4th generation ceramic-on-ceramic bearing may accentuate the conditions facilitating noise formation; however the current literature is insufficient. Clinically, squeaking may manifest in extreme hip positions or during normal gait cycle however it is rarely associated with pain. Evaluations of patients with squeaking include clinical and radiographic assessments. Computer tomography is recommended as it can better reveal ceramic breakage and implant malposition. The treatments for most squeaking patients include reassurance and activity modification. However for some, noise can be a problem, requiring further surgical intervention. In the occurrence of ceramic fracture, implant failure, extreme components malposition, instability and impingement, surgery should be advised. This review will aim to discuss the current literature regarding squeaking. PMID:26601063

  5. Anatomically shaped tissue-engineered cartilage with tunable and inducible anticytokine delivery for biological joint resurfacing

    PubMed Central

    Moutos, Franklin T.; Glass, Katherine A.; Compton, Sarah A.; Ross, Alison K.; Gersbach, Charles A.; Estes, Bradley T.

    2016-01-01

    Biological resurfacing of entire articular surfaces represents an important but challenging strategy for treatment of cartilage degeneration that occurs in osteoarthritis. Not only does this approach require anatomically sized and functional engineered cartilage, but the inflammatory environment within an arthritic joint may also inhibit chondrogenesis and induce degradation of native and engineered cartilage. The goal of this study was to use adult stem cells to engineer anatomically shaped, functional cartilage constructs capable of tunable and inducible expression of antiinflammatory molecules, specifically IL-1 receptor antagonist (IL-1Ra). Large (22-mm-diameter) hemispherical scaffolds were fabricated from 3D woven poly(ε-caprolactone) (PCL) fibers into two different configurations and seeded with human adipose-derived stem cells (ASCs). Doxycycline (dox)-inducible lentiviral vectors containing eGFP or IL-1Ra transgenes were immobilized to the PCL to transduce ASCs upon seeding, and constructs were cultured in chondrogenic conditions for 28 d. Constructs showed biomimetic cartilage properties and uniform tissue growth while maintaining their anatomic shape throughout culture. IL-1Ra–expressing constructs produced nearly 1 µg/mL of IL-1Ra upon controlled induction with dox. Treatment with IL-1 significantly increased matrix metalloprotease activity in the conditioned media of eGFP-expressing constructs but not in IL-1Ra–expressing constructs. Our findings show that advanced textile manufacturing combined with scaffold-mediated gene delivery can be used to tissue engineer large anatomically shaped cartilage constructs that possess controlled delivery of anticytokine therapy. Importantly, these cartilage constructs have the potential to provide mechanical functionality immediately upon implantation, as they will need to replace a majority, if not the entire joint surface to restore function. PMID:27432980

  6. Anatomically shaped tissue-engineered cartilage with tunable and inducible anticytokine delivery for biological joint resurfacing.

    PubMed

    Moutos, Franklin T; Glass, Katherine A; Compton, Sarah A; Ross, Alison K; Gersbach, Charles A; Guilak, Farshid; Estes, Bradley T

    2016-08-01

    Biological resurfacing of entire articular surfaces represents an important but challenging strategy for treatment of cartilage degeneration that occurs in osteoarthritis. Not only does this approach require anatomically sized and functional engineered cartilage, but the inflammatory environment within an arthritic joint may also inhibit chondrogenesis and induce degradation of native and engineered cartilage. The goal of this study was to use adult stem cells to engineer anatomically shaped, functional cartilage constructs capable of tunable and inducible expression of antiinflammatory molecules, specifically IL-1 receptor antagonist (IL-1Ra). Large (22-mm-diameter) hemispherical scaffolds were fabricated from 3D woven poly(ε-caprolactone) (PCL) fibers into two different configurations and seeded with human adipose-derived stem cells (ASCs). Doxycycline (dox)-inducible lentiviral vectors containing eGFP or IL-1Ra transgenes were immobilized to the PCL to transduce ASCs upon seeding, and constructs were cultured in chondrogenic conditions for 28 d. Constructs showed biomimetic cartilage properties and uniform tissue growth while maintaining their anatomic shape throughout culture. IL-1Ra-expressing constructs produced nearly 1 µg/mL of IL-1Ra upon controlled induction with dox. Treatment with IL-1 significantly increased matrix metalloprotease activity in the conditioned media of eGFP-expressing constructs but not in IL-1Ra-expressing constructs. Our findings show that advanced textile manufacturing combined with scaffold-mediated gene delivery can be used to tissue engineer large anatomically shaped cartilage constructs that possess controlled delivery of anticytokine therapy. Importantly, these cartilage constructs have the potential to provide mechanical functionality immediately upon implantation, as they will need to replace a majority, if not the entire joint surface to restore function. PMID:27432980

  7. Strain and micromotion in intact and resurfaced composite femurs: experimental and numerical investigations.

    PubMed

    Pal, Bidyut; Gupta, Sanjay; New, Andrew M R; Browne, Martin

    2010-07-20

    Understanding the load transfer within a resurfaced femur is necessary to determine the influence of mechanical factors on potential failure mechanisms such as early femoral neck fractures and stress shielding. In this study, an attempt has been made to measure the stem-bone micromotion and implant cup-bone relative displacements (along medial-lateral and anterior-posterior direction), in addition to surface strains at different locations and orientations on the proximal femur and to compare these measurements with those predicted by equivalent FE models. The loading and the support conditions of the experiment were closely replicated in the FE models. A new experimental set-up has been developed, with specially designed fixtures and load application mechanism, which can effectively impose bending and deflection of the tested femurs, almost in any direction. High correlation coefficient (0.92-0.95), low standard error of the estimate (170-379 muepsilon) and low percentage error in regression slope (12.8-17.5%), suggested good agreement between the numerical and measured strains. The effect of strain shielding was observed in two (out of eight) strain gauges located on the posterior side. A pronounced strain increase occurred in strain gauges located on the anterior head and neck regions after implantation. Experimentally measured stem-bone micromotion and implant cup-bone relative displacements (0-13.7 microm) were small and similar in trends predicted by the FE models (0-25 microm). Despite quantitative deviations in the measured and numerical results, it appears that the FE model can be used as a valid predictor of the actual strain and stem-bone micromotion. PMID:20392448

  8. Improved SB2 orbits for HIP 12081 and HIP 87895

    NASA Astrophysics Data System (ADS)

    Halbwachs, J.-L.; Arenou, F.; Guillout, P.; Pourbaix, D.; Tal-Or, L.; Famaey, B.; Lebreton, Y.; Mazeh, T.

    2013-11-01

    We are observing a selection of about 70 double-lined binaries (SB2s) with the T193/SOPHIE in order to improve their orbital elements. Our goal is to obtain the masses of the components with a 1 % accuracy when the astrometric observations of Gaia are available. After 6 semesters of observations, the two best observed stars are HIP 12081 and HIP 87895. These stars are used to verify that the 1 % accuracy could really be obtained at the end of the programme. The radial velocities of their components were derived using the TODMOR algorithm, and their orbital elements were calculated. It appears that the minimum masses of the components of HIP 12081 are already both obtained with an accuracy around 0.5 %. For HIP 87895, the relative precisions of the minimum masses of the primary and of the secondary component are 2.7 and 1.5 %, respectively, but they were obtained from only 9 spectra and they should be improved once more observations have been obtained. Ancient interferometric observations of HIP 87895 are also taken into account and the actual masses of the components are derived. Although these measurements are far from being as accurate as those expected from Gaia, the relative errors of the masses are only 2.6 and 1.5 % respectively. We thus conclude that our programme would lead to masses with the announced accuracy if the observations are continued.

  9. Autologous Matrix-Induced Chondrogenesis (AMIC): Combining Microfracturing and a Collagen I/III Matrix for Articular Cartilage Resurfacing.

    PubMed

    Benthien, J P; Behrens, P

    2010-01-01

    Options for the treatment of cartilage defects include chondral resurfacing with abrasion, debridement, autologous chondrocyte transplantation (ACT), matrix-induced chondrocyte transplantation (MACI), or osteochondral autologous transplantation (OATS). This article describes the new method of autologous matrix-induced chondrogenesis (AMIC), a 1-step procedure combining subchondral microfracture with the fixation of a collagen I/III membrane by a partially autologous fibrin glue. Indications and contraindications are provided; a technical note is given. This method is primarily applied in osteochondral lesions of the knee and ankle joints; other joints may qualify.

  10. Developmental dysplasia of the hip

    PubMed Central

    Noordin, Shahryar; Umer, Masood; Hafeez, Kamran; Nawaz, Haq

    2010-01-01

    Developmental dysplasia of the hip (DDH) is a spectrum of anatomical abnormalities of the hip joint in which the femoral head has an abnormal relationship with the acetabulum. Most studies report an incidence of 1 to 34 cases per 1,000 live births and differences could be due to different diagnostic methods and timing of evaluation. Risk factors include first born status, female sex, positive family history, breech presentation and oligohydramnios. Clinical presentations of DDH depend on the age of the child. Newborns present with hip instability, infants have limited hip abduction on examination, and older children and adolescents present with limping, joint pain, and/or osteoarthritis. Repeated, careful examination of all infants from birth and throughout the first year of life until the child begins walking is important to prevent late cases. Provocative testing includes the Barlow and Ortolani maneuvers. Other signs, such as shorting of the femur with hips and knees flexed (Galeazzi sign), asymmetry of the thigh or gluteal folds, and discrepancy of leg lengths are potential clues. Treatment depends on age at presentation and outcomes are much better when the child is treated early, particularly during the first six months of life. PMID:21808709

  11. Cementless Hydroxyapatite Coated Hip Prostheses

    PubMed Central

    Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda

    2015-01-01

    More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality. PMID:25802848

  12. The unstable total hip replacement

    PubMed Central

    D'Angelo, F; Murena, L; Zatti, G; Cherubino, P

    2008-01-01

    Background: Dislocation is one of the most common complications of total hip arthroplasty with a reported dislocation rate of 3.2%. Despite increased experience with hip replacement, the overall rate has not yet changed. The aim of this paper is to review the most recent literature published on this topic and indexed in Medline, in order to clarify the main risk factors, and to standardize a treatment protocol of such an important complication of prosthetic surgery. Materials and Methods: Medline database was searched using key words: “hip dislocation”, “hip instability” from 1980-2007. Studies were eligible for review and included if they met the following criteria: (1) publication in English, (2) clinical trials (3) review papers. Results: The risk of first-time dislocation as a function of time after the surgery is not well understood. Most, but not all, series have demonstrated that the risk of dislocation is highest during the first few months after hip arthroplasty; however, first-time late dislocation can also occur many years after the procedure. Several risk factors were described, including the surgical approach, the diameter of the head, impingement, component malposition, insufficient abductor musculature. In addition, there are also many treatment options, such as long-term bracing after closed reduction, component reorientation, capsulorraphy, trochanteric advancement, increasing offset, exchange of the modular head and the polyethylene liner, insertion of constrained liner. Conclusion: Preventing hip dislocation is obviously the best strategy. Surgeons must take into account patient and surgical risk factors. For patients at high risk for dislocation the surgeon should accurately restore leg length and femoral offset; the use of larger femoral heads, posterior transosseous repair of the capsulotendinous envelope if posterior approach is chosen or the use of a lateral approach should be considered. Proper patient education and postoperative

  13. The use of hip arthroscopy in the management of the pediatric hip

    PubMed Central

    Roy, Dennis R.

    2016-01-01

    Arthroscopy of the pediatric hip began in 1977 with a publication by Gross. Interest was relatively slow to develop in the 1980s and 1990s. Coupled with the success of hip arthroscopy in the adult, interest heightened in applying the procedure to a variety of pediatric hip disorders, given that the alternative was an open surgical hip dislocation. The success of this initial group of pediatric hip arthroscopist’s has further expanded the application of hip arthroscopy as the primary or adjunct procedure for the management of intra-articular problems of the pediatric hip. PMID:27583144

  14. Subspine Hip Impingement: An Unusual Cause of Hip Pain in an Elite Weightlifter.

    PubMed

    Nabhan, Dustin C; Moreau, William J; McNamara, Shannen C; Briggs, Karen K; Philippon, Marc J

    2016-01-01

    Anterior hip pain can be difficult to diagnose due to the many pathologies and overlapping pain patterns that exist in the hip region. Clinical findings of pain at the anterior inferior iliac spine with passive hip flexion, proximal quadriceps pain and weakness, and painful impingement tests of the hip may be indicative of subspine hip impingement. This report describes the diagnosis and treatment of anterior hip pain, including subspine impingement and femoroacetabular impingement in an elite weightlifter. This case also describes how with the correct diagnosis and treatment, the athlete returned to play to her previous level of sport 11 months after a complex hip injury. PMID:27618239

  15. The use of hip arthroscopy in the management of the pediatric hip.

    PubMed

    Roy, Dennis R

    2016-07-01

    Arthroscopy of the pediatric hip began in 1977 with a publication by Gross. Interest was relatively slow to develop in the 1980s and 1990s. Coupled with the success of hip arthroscopy in the adult, interest heightened in applying the procedure to a variety of pediatric hip disorders, given that the alternative was an open surgical hip dislocation. The success of this initial group of pediatric hip arthroscopist's has further expanded the application of hip arthroscopy as the primary or adjunct procedure for the management of intra-articular problems of the pediatric hip. PMID:27583144

  16. The Fatigue of Water Ice: Insight into the Tectonic Resurfacing of Tidally Deformed Icy Satellites

    NASA Astrophysics Data System (ADS)

    Hammond, N. P.; Barr, A. C.; Hirth, G.; Cooper, R. F.

    2015-12-01

    allow us to determine how subcritical crack growth rates vary as a function of stress intensity, temperature and frequency. We will use our data to extrapolate to conditions present in the near-surface of icy satellites to determine the effect of fatigue on icy satellite resurfacing. [1] Hubner H. and Jillik J., (1977) J. Material Sci. 12.

  17. Hip Squeaking after Ceramic-on-ceramic Total Hip Arthroplasty

    PubMed Central

    Wu, Guo-Liang; Zhu, Wei; Zhao, Yan; Ma, Qi; Weng, Xi-Sheng

    2016-01-01

    Objective: The present study aimed to review the characteristics and influencing factors of squeaking after ceramic-on-ceramic (CoC) total hip arthroplasty (THA) and to analyze the possible mechanisms of the audible noise. Data Sources: The data analyzed in this review were based on articles from PubMed and Web of Science. Study Selection: The articles selected for review were original articles and reviews found based on the following search terms: “total hip arthroplasty”, “ceramic-on-ceramic”, “hip squeaking”, and “hip noise.” Results: The mechanism of the squeaking remains unknown. The possible explanations included stripe wear, edge loading, a third body, fracture of the ceramic liner, and resonance of the prosthesis components. Squeaking occurrence is influenced by patient, surgical, and implant factors. Conclusions: Most studies indicated that squeaking after CoC THA was the consequence of increasing wear or impingement, caused by prosthesis design, patient characteristics, or surgical factors. However, as conflicts exist among different articles, the major reasons for the squeaking remain to be identified. PMID:27453238

  18. Surrogate markers of long-term outcome in primary total hip arthroplasty

    PubMed Central

    Malak, T. T.; Broomfield, J. A. J.; Palmer, A. J. R.; Hopewell, S.; Carr, A.; Brown, C.; Prieto-Alhambra, D.

    2016-01-01

    Objectives High failure rates of metal-on-metal hip arthroplasty implants have highlighted the need for more careful introduction and monitoring of new implants and for the evaluation of the safety of medical devices. The National Joint Registry and other regulatory services are unable to detect failing implants at an early enough stage. We aimed to identify validated surrogate markers of long-term outcome in patients undergoing primary total hip arthroplasty (THA). Methods We conducted a systematic review of studies evaluating surrogate markers for predicting long-term outcome in primary THA. Long-term outcome was defined as revision rate of an implant at ten years according to National Institute of Health and Care Excellence guidelines. We conducted a search of Medline and Embase (OVID) databases. Separate search strategies were devised for the Cochrane database and Google Scholar. Each search was performed to include articles from the date of their inception to June 8, 2015. Results Our search strategy identified 1082 studies of which 115 studies were included for full article review. Following review, 17 articles were found that investigated surrogate markers of long-term outcome. These included one systematic review, one randomised control trial (RCT), one case control study and 13 case series. Validated surrogate markers included Radiostereometric Analysis (RSA) and Einzel-Bild-Röntgen-Analyse (EBRA), each measuring implant migration and wear. We identified five RSA studies (one systematic review and four case series) and four EBRA studies (one RCT and three case series). Patient Reported Outcome Measures (PROMs) at six months have been investigated but have not been validated against long-term outcomes. Conclusions This systematic review identified two validated surrogate markers of long-term primary THA outcome: RSA and EBRA, each measuring implant migration and wear. We recommend the consideration of RSA in the pre-market testing of new implants. EBRA can

  19. Hip-Hop and the Academic Canon

    ERIC Educational Resources Information Center

    Abe, Daudi

    2009-01-01

    Over the last 30 years, the hip-hop movement has risen from the margins to become the preeminent force in US popular culture. In more recent times academics have begun to harness the power of hip-hop culture and use it as a means of infusing transformative knowledge into the mainstream academic discourse. On many college campuses, hip-hop's…

  20. Hip Replacement - Multiple Languages: MedlinePlus

    MedlinePlus

    ... Hip Replacement (Arabic) العربية Bilingual PDF Health Information Translations Bosnian (Bosanski) Total Hip Replacement Potpuna zamjena kuka - Bosanski (Bosnian) Bilingual PDF Health Information Translations Chinese - Simplified (简体中文) Total Hip Replacement 全髋关节置换 - 简体中文 ( ...

  1. Total hip replacement for arthritis following tuberculosis of hip

    PubMed Central

    Kumar, Vijay; Garg, Bhavuk; Malhotra, Rajesh

    2015-01-01

    AIM: To present the results of total hip arthroplasty (THA) for post tubercular arthritis of the hip joint. METHODS: Sixty-five patients (45 male, 20 female) with previously treated tuberculosis of the hip joint underwent cementless THA for post tubercular arthritis. The average age at the time of THA was 48 years (range 29 to 65 years). Erythrocyte sedimentation rate, C reactive protein, chest X-ray and contrast enhanced magnetic resonance imaging were done preoperatively to confirm resolution of the disease and to rule out any residual disease. Intra-operative samples were taken for microbiological examination, polymerase chain reaction (PCR) and histological examination. Patients were started on anti-tubercular drugs one week before the operation and continued for 6 mo post operatively. The patients were followed up clinically using the Harris hip score as well as radiologically for any loosening of the implants, osteolysis and any recurrence of tuberculosis. Any complications especially the recurrence of the infection was also recorded. RESULTS: The mean interval from completion of antitubercular therapy for tuberculosis to surgery was 4.2 years (range, 2-6 years). Preoperatively, 17 patients had ankylosis whereas 48 patients had functional but painful range of motion. The mean surgical time was 97 min (range, 65-125) whereas the mean blood loss was 600 mL (range, 400-900 mL). The average follow up was 8.3 years (range 6-11 years). The average Harris Hip score improved from 27 preoperatively to 91 at the final follow up. Seventeen patients had acetabular protrusion which was managed with impaction grafting and cementless acetabular cup. The bone graft had consolidated in all these 17 patients at the follow up. Two patients developed discharging sinuses at 9 and 11 mo postoperatively respectively. The discharge tested positive for tuberculosis on the PCR. Both these patients were put on antitubercular therapy for another year. Both of them recovered and had no

  2. 21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint femoral (hemi-hip) metal/polymer... § 888.3390 Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis is a...

  3. 21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint femoral (hemi-hip) metal/polymer... § 888.3390 Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis is a...

  4. 21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint femoral (hemi-hip) metal/polymer... § 888.3390 Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis is a...

  5. 21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal 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 femoral (hemi-hip) trunnion-bearing... Devices § 888.3380 Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis is a...

  6. 21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal 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 femoral (hemi-hip) trunnion-bearing... Devices § 888.3380 Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis is a...

  7. 21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint femoral (hemi-hip) metal/polymer... § 888.3390 Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis is a...

  8. 21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal 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 femoral (hemi-hip) trunnion-bearing... Devices § 888.3380 Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis is a...

  9. 21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint femoral (hemi-hip) metal/polymer... § 888.3390 Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis is a...

  10. 21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal 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 femoral (hemi-hip) trunnion-bearing... Devices § 888.3380 Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis is a...

  11. 21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal 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 femoral (hemi-hip) trunnion-bearing... Devices § 888.3380 Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis is a...

  12. The impact of proximal femoral morphology on failure strength with a mid-head resection short-stem hip arthroplasty.

    PubMed

    Olsen, Michael; Al Saied, Mohamed; Morison, Zachary; Sellan, Michael; Waddell, James P; Schemitsch, Emil H

    2014-12-01

    Mid-head resection short-stem hip arthroplasty is a conservative alternative to conventional total hip replacement and addresses proximal fixation challenges in patients not suitable for hip resurfacing. It is unclear whether proximal femoral morphology impacts the ultimate failure load of mid-head resection implanted femurs, thus the aim of this study was to investigate the effect of native neck-shaft angle (NSA) and coronal implant alignment on proximal femoral strength. In total, 36 synthetic femurs with two different proximal femoral morphologies were utilized in this study. Of them, 18 femurs with a varus NSA of 120° and 18 femurs with a valgus NSA of 135° were each implanted with a mid-head resection prosthesis. Femurs within the two different femoral morphology groups were divided into three equal coronal implant alignment groups: 10° valgus, 10° varus or neutral alignment. Prepared femurs were tested for stiffness and to failure in axial compression. There was no significant difference in stiffness nor failure load between femurs implanted with valgus-, varus- or neutrally aligned implants in femurs with a NSA of 120° (p = 0.396, p = 0.111, respectively). Femurs implanted in valgus orientation were significantly stiffer and failed at significantly higher loads than those implanted in varus alignment in femurs with a NSA of 135° (p = 0.001, p = 0.007, respectively). A mid-head resection short-stem hip arthroplasty seems less sensitive to clinically relevant variations of coronal implant alignment and may be more forgiving upon implantation in some femoral morphologies, however, a relative valgus component alignment is recommended.

  13. Hip-Hop Pop Art

    ERIC Educational Resources Information Center

    Talley, Clarence, Sr.

    2011-01-01

    Art has a way of helping students better understand and appreciate the world around them, particularly the things that are most important to them. Hip hop is one of those generational genres that capture the attention of young students like few other things do. Drawing on this genre to get students to create art is an excellent way to demonstrate…

  14. [Congenital hip dysplasia, screening and therapy].

    PubMed

    Kolb, A; Windhager, R; Chiari, C

    2015-11-01

    Congenital hip dysplasia and hip dislocation are relatively common pathological conditions of the musculoskeletal system in infants. An early and certain diagnosis can now be achieved by sonographic hip screening within the framework of screening examination programs. This early diagnostic procedure in infants is essential particularly for a conservative treatment strategy. Therefore, apart from possessing in-depth knowledge, training of the examiner in specialist courses is of central importance. This article presents an overview of the entity of congenital hip dysplasia and hip dislocation, the diagnostics and treatment with special emphasis on recent developments. PMID:26489825

  15. Hip Imaging in Athletes: Sports Imaging Series.

    PubMed

    Agten, Christoph A; Sutter, Reto; Buck, Florian M; Pfirrmann, Christian W A

    2016-08-01

    Hip or groin pain in athletes is common and clinical presentation is often nonspecific. Imaging is a very important diagnostic step in the work-up of athletes with hip pain. This review article provides an overview on hip biomechanics and discusses strategies for hip imaging modalities such as radiography, ultrasonography, computed tomography, and magnetic resonance (MR) imaging (MR arthrography and traction MR arthrography). The authors explain current concepts of femoroacetabular impingement and the problem of high prevalence of cam- and pincer-type morphology in asymptomatic persons. With the main focus on MR imaging, the authors present abnormalities of the hip joint and the surrounding soft tissues that can occur in athletes: intraarticular and extraarticular hip impingement syndromes, labral and cartilage disease, microinstability of the hip, myotendinous injuries, and athletic pubalgia. (©) RSNA, 2016. PMID:27429142

  16. Techniques and Results for Open Hip Preservation

    PubMed Central

    Levy, David M.; Hellman, Michael D.; Haughom, Bryan; Stover, Michael D.; Nho, Shane J.

    2015-01-01

    While hip arthroscopy grows in popularity, there are still many circumstances under which open hip preservation is the most appropriately indicated. This article specifically reviews open hip preservation procedures for a variety of hip conditions. Femoral acetabular impingement may be corrected using an open surgical hip dislocation. Acetabular dysplasia may be corrected using a periacetabular osteotomy. Acetabular protrusio may require surgical hip dislocation with rim trimming and a possible valgus intertrochanteric osteotomy. Legg–Calve–Perthes disease produces complex deformities that may be better served with osteotomies of the proximal femur and/or acetabulum. Chronic slipped capital femoral epiphysis may also benefit from a surgical hip dislocation and/or proximal femoral osteotomy. PMID:26649292

  17. Techniques and Results for Open Hip Preservation.

    PubMed

    Levy, David M; Hellman, Michael D; Haughom, Bryan; Stover, Michael D; Nho, Shane J

    2015-01-01

    While hip arthroscopy grows in popularity, there are still many circumstances under which open hip preservation is the most appropriately indicated. This article specifically reviews open hip preservation procedures for a variety of hip conditions. Femoral acetabular impingement may be corrected using an open surgical hip dislocation. Acetabular dysplasia may be corrected using a periacetabular osteotomy. Acetabular protrusio may require surgical hip dislocation with rim trimming and a possible valgus intertrochanteric osteotomy. Legg-Calve-Perthes disease produces complex deformities that may be better served with osteotomies of the proximal femur and/or acetabulum. Chronic slipped capital femoral epiphysis may also benefit from a surgical hip dislocation and/or proximal femoral osteotomy. PMID:26649292

  18. [Prevention with hip protectors. Biomechanical aspects in falls and hip fractures].

    PubMed

    Lauritzen, J B

    1996-12-01

    The cascade of events leading to hip fracture is: a fall, protective responses, impact to the hip, local energy absorption and bone strength. A fall from standing height on the hip corresponds to a force of about 3500 N and the bone strength of the proximal femur in elderly women and men ranges between 2000 to 6000 N. Efficient hip protective systems have been developed and may be a significant factor in the prevention of hip fractures among the elderly with propensity to fall and osteoporosis. Theoretically, more than 90 per cent of all hip fractures can be prevented, and a substantial reduction in the rate of hip fractures can be obtained, when systematic intervention programs are initiated among nursing home residents. Prevention of hip fractures among home dwellers may be a greater challenge, although preliminary results seem promising. Improvement in design has made the protectors more compliant and may facilitate the aim of preventing hip fractures.

  19. Reproduction of Hip Offset and Leg Length in Navigated Total Hip Arthroplasty: How Accurate Are We?

    PubMed

    Ellapparadja, Pregash; Mahajan, Vivek; Deakin, Angela H; Deep, Kamal

    2015-06-01

    This study assesses how accurately we can restore hip offset and leg length in navigated total hip arthroplasty (THA). 152 consecutive patients with navigated THA formed the study group. The contra-lateral hip formed control for measuring hip offset and leg length. All radiological measurements were made using Orthoview digital software. In the normal hip offset group, the mean is 75.73 (SD- 8.61). In the reconstructed hip offset group, the mean is 75.35 (SD - 7.48). 95.39% had hip offset within 6 mm of opposite side while 96.04% had leg length restored within 6 mm of contra-lateral side. Equivalence test revealed that the two groups of hip offsets were essentially the same. We conclude that computer navigation can successfully reproduce hip offset and leg length accurately.

  20. Frontal plane kinematics of the hip during running: Are they related to hip anatomy and strength?

    PubMed

    Baggaley, Michael; Noehren, Brian; Clasey, Jody L; Shapiro, Robert; Pohl, Michael B

    2015-10-01

    Excessive hip adduction has been associated with a number of lower extremity overuse running injuries. The excessive motion has been suggested to be the result of reduced strength of the hip abductor musculature. Hip anatomical alignment has been postulated to influence hip abduction (HABD) strength and thus may impact hip adduction during running. The purpose of this study was to investigate the relationship between hip anatomy, HABD strength, and frontal plane kinematics during running. Peak isometric HABD strength, 3D lower extremity kinematics during running, femoral neck-shaft angle (NSA), and pelvis width-femur length (PW-FL) ratio were recorded for 25 female subjects. Pearson correlations (p<0.05) were performed between variables. A fair relationship was observed between femoral NSA and HABD strength (r=-0.47, p=0.02) where an increased NSA was associated with reduced HABD strength. No relationship was observed between HABD strength and hip adduction during running. None of the anatomical measurements, NSA or PW-FL, were associated with hip adduction during running. Deviations in the femoral NSA have a limited ability to influence peak isometric hip abduction strength or frontal plane hip kinematics during running. Hip abduction strength does also not appear to be linked with changes in hip kinematics. These findings in healthy individuals question whether excessive hip adduction typically seen in female runners with overuse injuries is caused by deviations in hip abduction strength or anatomical structure.

  1. Efficacy and Safety of Fractional CO2 Laser Resurfacing in Non-hypertrophic Traumatic and Burn Scars

    PubMed Central

    Majid, Imran; Imran, Saher

    2015-01-01

    Background: Fractional photothermolysis is one of the most effective treatment options used to resurface scars of different aetiologies. Aim: To assess the efficacy and safety of fractional CO2 laser resurfacing treatment in the management of non-hypertrophic traumatic and burn scars. Materials and Methods: Twenty-five patients affected by non-hypertrophic traumatic and burn scars were treated with four sessions of fractional CO2 laser resurfacing treatment at 6-weekly intervals. Patients were photographed at each visit and finally, 3 months after the end of treatment schedule. Response to treatment was assessed clinically as well as by comparing the initial photograph of the patient with the one taken at the last follow-up visit 3-months after the final treatment session. Changes in skin texture, surface irregularity and pigmentation were assessed on a quartile grading scale and scored individually from 0 to 4. A mean of the three individual scores was calculated and the response was labelled as ‘excellent’ if the mean score achieved was >2. A score of 1-2 was labeled as good response while a score below 1 was labeled as ‘poor’ response. The subjective satisfaction of each patient with the treatment offered was also assessed at the last follow-up visit. Results: The commonest site of scarring treated was the face followed by hands. Response to treatment was rated as excellent in 60% (15/25) patients while 24% (6/25) and 16% (4/25) patients were labeled as good and poor responders, respectively. Skin texture showed better response than other variables with average score of 2.44. Linear post-traumatic scars were seen to respond less than other morphological types. Majority of the patients (19 out of 25) were highly satisfied with the treatment offered. No long-term adverse effects were noted in any patient. Conclusions: Fractional photothermolysis with a fractional CO2 laser gives excellent results in patients with post-burn scars with minimal adverse

  2. South Pole-Aitken Basin: Evidence for Post-Basin Resurfacing from Lunar Orbiter Laser Altimeter (LOLA) Data

    NASA Astrophysics Data System (ADS)

    Head, J. W.; Fassett, C.; Kadish, S.; Smith, D. E.; Zuber, M. T.; Neumann, G. A.; Mazarico, E.

    2010-12-01

    The lunar farside South Pole-Aitken Basin is the largest and oldest documented basin on the Moon and is thus of interest from the point of view of the scale of production of impact melt at large basin-event sizes and its ring structure and potential depth of sampling at such a large diameter. We used new LOLA data from the Lunar Reconnaissance Orbiter 1) to characterize the basin interior topography, 2) to assess the nature of the nearby and relatively pristine Orientale basin and compare it to the SPA interior, and 3) to compile a new global crater database of all lunar craters ≥20 km in diameter and to assess the population of impact craters superposed on the SPA interior and exterior. We find that impact crater size-frequency distribution plots show that the exterior of the SPA basin is similar to the most heavily cratered regions of the Moon, but that the interior of the basin has a deficiency of craters in the 20-64 km diameter crater range. One interpretation of these data is that some resurfacing process (or processes) has modified the superposed crater population. Among the candidates are 1) impact crater proximity weathering/degradation by adjacent (e.g., Apollo) and nearby (e.g., Orientale) impact basin ejecta, 2) volcanic resurfacing by early non-mare volcanism, cryptomaria and/or maria, and 3) viscous relaxation removing crater topography. We consider viscous relaxation of crater topography to be the least likely due to the wavelength dependence of the process (rim-crests should be preserved and thus detected in our crater counts). Careful analysis of the impact ejecta thickness radial decay suggests that it is an important resurfacing mechanism within a basin radius from the rim crest, but is unlikely to be sufficient to explain the observed deficiency. Morphometric analysis of impact craters, modeling, and simulations of volcanic flooding suggest that the deficiency may be related to the patchy distribution of cryptomaria, suspected from mineralogic

  3. The Epidemiology and National Trends of Bearing Surface Usage in Primary Total Hip Arthroplasty in Korea

    PubMed Central

    Yoon, Pil Whan; Kim, Yunjung; Yoo, Seungmi; Lee, Sahnghoon; Kim, Hee Joong

    2016-01-01

    Background We analyzed the data for primary total hip arthroplasty (THA) in the Korean nationwide database to assess (1) the epidemiology and national trends of bearing surface usage in THAs and (2) the prevalence of each type of bearing surface according to age, gender, hospital type, primary payer, and hospital procedure volume. Methods A total of 30,881 THAs were analyzed using the Korean Health Insurance Review and Assessment Service database for 2007 through 2011. Bearing surfaces were sub-grouped according to device code for national health insurance claims and consisted of ceramic-on-ceramic (CoC), metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), and metal-on-metal (MoM). The prevalence of each type of bearing surface was calculated and stratified by age, gender, hospital type, primary payer, and procedure volume of each hospital. Results CoC was the most frequently used bearing surface (76.7%), followed by MoP (11.9%), CoP (7.3%), and MoM (4.1%). The proportion of THAs using a CoC bearing surface increased steadily from 71.6% in 2007 to 81.4% in 2011, whereas the proportions using CoP, MoP, and MoM bearing surfaces decreased. The order of prevalence was identical to that in the general population regardless of age, gender, hospital type, primary payer, and hospital procedure volume. Conclusions The trends and epidemiology of bearing surface usage in THAs in Korea are different from those in other countries, and the CoC bearing surface is the most prevalent articulation. In future, the results of a large-scale study using nationwide data of THAs involving a CoC bearing surface will be reported in Korea. PMID:26929796

  4. Internal snapping hip syndrome in dynamic ultrasonography

    PubMed Central

    Maczuch, Jarosław; Skupiński, Jarosław; Kukawska-Sysio, Karolina; Wawrzynek, Wojciech

    2016-01-01

    Snapping hip syndrome is an audible or palpable snap in a hip joint during movement which may be accompanied by pain or locking. It is typically seen in young athletes performing activities requiring repeated extreme movements of the hip. It may also follow a physical trauma, intramuscular injections or surgeries. There are two main forms of snapping hip: extra- or intra-articular. Extra-articular snapping hip is elicited by an abnormal movement of specific tendons and is divided into two forms: internal and external. The internal form of snapping hip syndrome is attributed to an abrupt movement of an iliopsoas tendon against an iliopectineal eminence. Radiograph results in patients with this form of snapping tend to be normal. Dynamic ultrasound is the gold standard diagnostic technique in both forms of extra-articular snapping hip syndrome. The objective of the following text is to describe a step-by-step dynamic ultrasonography examination in internal extra-articular snapping hip syndrome in accordance to the proposed checklist protocol. To evaluate abrupt movement of an involved tendon, the patient needs to perform specific provocation tests during the examination. With its real-time imaging capabilities, dynamic ultrasonography detects the exact mechanism of the abnormal tendon friction during hip movement in a noninvasive way. It also allows for a diagnosis of additional hip tissue changes which may be causing the pain. PMID:27679733

  5. Internal snapping hip syndrome in dynamic ultrasonography.

    PubMed

    Piechota, Małgorzata; Maczuch, Jarosław; Skupiński, Jarosław; Kukawska-Sysio, Karolina; Wawrzynek, Wojciech

    2016-09-01

    Snapping hip syndrome is an audible or palpable snap in a hip joint during movement which may be accompanied by pain or locking. It is typically seen in young athletes performing activities requiring repeated extreme movements of the hip. It may also follow a physical trauma, intramuscular injections or surgeries. There are two main forms of snapping hip: extra- or intra-articular. Extra-articular snapping hip is elicited by an abnormal movement of specific tendons and is divided into two forms: internal and external. The internal form of snapping hip syndrome is attributed to an abrupt movement of an iliopsoas tendon against an iliopectineal eminence. Radiograph results in patients with this form of snapping tend to be normal. Dynamic ultrasound is the gold standard diagnostic technique in both forms of extra-articular snapping hip syndrome. The objective of the following text is to describe a step-by-step dynamic ultrasonography examination in internal extra-articular snapping hip syndrome in accordance to the proposed checklist protocol. To evaluate abrupt movement of an involved tendon, the patient needs to perform specific provocation tests during the examination. With its real-time imaging capabilities, dynamic ultrasonography detects the exact mechanism of the abnormal tendon friction during hip movement in a noninvasive way. It also allows for a diagnosis of additional hip tissue changes which may be causing the pain. PMID:27679733

  6. Internal snapping hip syndrome in dynamic ultrasonography

    PubMed Central

    Maczuch, Jarosław; Skupiński, Jarosław; Kukawska-Sysio, Karolina; Wawrzynek, Wojciech

    2016-01-01

    Snapping hip syndrome is an audible or palpable snap in a hip joint during movement which may be accompanied by pain or locking. It is typically seen in young athletes performing activities requiring repeated extreme movements of the hip. It may also follow a physical trauma, intramuscular injections or surgeries. There are two main forms of snapping hip: extra- or intra-articular. Extra-articular snapping hip is elicited by an abnormal movement of specific tendons and is divided into two forms: internal and external. The internal form of snapping hip syndrome is attributed to an abrupt movement of an iliopsoas tendon against an iliopectineal eminence. Radiograph results in patients with this form of snapping tend to be normal. Dynamic ultrasound is the gold standard diagnostic technique in both forms of extra-articular snapping hip syndrome. The objective of the following text is to describe a step-by-step dynamic ultrasonography examination in internal extra-articular snapping hip syndrome in accordance to the proposed checklist protocol. To evaluate abrupt movement of an involved tendon, the patient needs to perform specific provocation tests during the examination. With its real-time imaging capabilities, dynamic ultrasonography detects the exact mechanism of the abnormal tendon friction during hip movement in a noninvasive way. It also allows for a diagnosis of additional hip tissue changes which may be causing the pain.

  7. Economic viability of geriatric hip fracture centers.

    PubMed

    Clement, R Carter; Ahn, Jaimo; Mehta, Samir; Bernstein, Joseph

    2013-12-01

    Management of geriatric hip fractures in a protocol-driven center can improve outcomes and reduce costs. Nonetheless, this approach has not spread as broadly as the effectiveness data would imply. One possible explanation is that operating such a center is not perceived as financially worthwhile. To assess the economic viability of dedicated hip fracture centers, the authors built a financial model to estimate profit as a function of costs, reimbursement, and patient volume in 3 settings: an average US hip fracture program, a highly efficient center, and an academic hospital without a specific hip fracture program. Results were tested with sensitivity analysis. A local market analysis was conducted to assess the feasibility of supporting profitable hip fracture centers. The results demonstrate that hip fracture treatment only becomes profitable when the annual caseload exceeds approximately 72, assuming costs characteristic of a typical US hip fracture program. The threshold of profitability is 49 cases per year for high-efficiency hip fracture centers and 151 for the urban academic hospital under review. The largest determinant of profit is reimbursement, followed by costs and volume. In the authors’ home market, 168 hospitals offer hip fracture care, yet 85% fall below the 72-case threshold. Hip fracture centers can be highly profitable through low costs and, especially, high revenues. However, most hospitals likely lose money by offering hip fracture care due to inadequate volume. Thus, both large and small facilities would benefit financially from the consolidation of hip fracture care at dedicated hip fracture centers. Typical US cities have adequate volume to support several such centers.

  8. Use of medical tourism for hip and knee surgery in osteoarthritis: a qualitative examination of distinctive attitudinal characteristics among Canadian patients

    PubMed Central

    2012-01-01

    Background Medical tourism is the term that describes patients’ international travel with the intention of seeking medical treatment. Some medical tourists go abroad for orthopaedic surgeries, including hip and knee resurfacing and replacement. In this article we examine the findings of interviews with Canadian medical tourists who went abroad for such surgeries to determine what is distinctive about their attitudes when compared to existing qualitative research findings about patients’ decision-making in and experiences of these same procedures in their home countries. Methods Fourteen Canadian medical tourists participated in semi-structured phone interviews, all of whom had gone abroad for hip or knee surgery to treat osteoarthritis. Transcripts were coded and thematically analysed, which involved comparing emerging findings to those in the existing qualitative literature on hip and knee surgery. Results Three distinctive attitudinal characteristics among participants were identified when interview themes were compared to findings in the existing qualitative research on hip and knee surgery in osteoarthritis. These attitudinal characteristics were that the medical tourists we spoke with were: (1) comfortable health-related decision-makers; (2) unwavering in their views about procedure necessity and urgency; and (3) firm in their desires to maintain active lives. Conclusions Compared to other patients reported on in the existing qualitative hip and knee surgery literature, medical tourists are less likely to question their need for surgery and are particularly active in their pursuit of surgical intervention. They are also comfortable with taking control of health-related decisions. Future research is needed to identify motivators behind patients’ pursuit of care abroad, determine if the attitudinal characteristics identified here hold true for other patient groups, and ascertain the impact of these attitudinal characteristics on surgical outcomes

  9. Osteonecrosis: avoiding total hip arthroplasty.

    PubMed

    Hungerford, David S

    2002-06-01

    Osteonecrosis of the femoral head afflicts approximately 20,000 new patients per year, at an average age of 38. Of the patients seen in our institution, 25% are <25 years old. Without treatment, most of these patients can be expected to need a total hip arthroplasty. Joint-preserving procedures have a significant failure rate, and some have significant morbidity. It is desirable to avoid or delay total hip arthroplasty because most patients with osteonecrosis outlive the current state-of-the-art prostheses. Four issues need to be weighed to arrive at a reasonable algorithm for the preservative treatment of osteonecrosis: i) patient risk factors, ii) morbidity of the proposed procedure, iii) size of the lesion, and iv) stage of the lesion. All of the issues must be considered to make sense out of a complex clinical situation.

  10. Total hip replacement for developmental dysplasia of hip and postoperative nursing.

    PubMed

    Zong, S J; Wang, F; Hu, S L

    2016-01-01

    This study was designed to determine the clinical effect of total hip replacement for the treatment of developmental dysplasia of the hip (DDH) and analyze the postoperative nursing. Sixty patients (78 hips) aged 18-75 years (average 58.6±2.31 years) who received total hip replacement for treatment of DDH at the Zhengzhou People’s Hospital, Henan, China, from April 2013 to June 2016 were selected as research subjects. Twenty-four patients were male (30 hips) and 36 were female (48 hips). Of the 60 patients, according to Crowe typing, 24 were type I (30 hips), 26 were type II (34 hips), 6 were type III (8 hips) and 4 were type IV (6 hips). According to the Harris hip score system, the score of all hips was 39.46±3.56 points average (18-56 points) before treatment and resulted as 89.60±4.25 points (79-98 points) at the last follow-up, showing a statistically significant difference (P < 0.05). Complications such as wound infection, dislocation, fracture of femoral shaft, femoral nerve and injury of sciatic nerve were not found after treatment. A total of 48 cases (58 hips) obtained excellent curative results (93.33% recovery), 8 cases (14 hips) good (92.31% recovery), and 4 cases (6 hips) medium. Total hip replacement proved to be effective in treating DDH and secondary osteoarthritis. Moreover, soft tissue release and an optimum degree recovery of anatomic form and physiological function of the diseased hip is an important basis for reconstructing the acetabulum and stabilizing acetabulum prosthesis. PMID:27049089

  11. Osteoporotic Hip and Spine Fractures

    PubMed Central

    Hill, Brian W.

    2014-01-01

    Hip and spine fractures represent just a portion of the burden of osteoporosis; however, these fractures require treatment and often represent a major change in lifestyle for the patient and their family. The orthopedic surgeon plays a crucial role, not only in the treatment of these injuries but also providing guidance in prevention of future osteoporotic fractures. This review provides a brief epidemiology of the fractures, details the surgical techniques, and outlines the current treatment guidelines for orthopedic surgeons. PMID:26246944

  12. Candida glabrata prosthetic hip infection.

    PubMed

    Bartalesi, Filippo; Fallani, Stefania; Salomoni, Elena; Marcucci, Massimiliano; Meli, Massimo; Pecile, Patrizia; Cassetta, Maria Iris; Latella, Leonardo; Bartoloni, Alessandro; Novelli, Andrea

    2012-11-01

    We present a case of a 60-year-old Caucasian woman carrying a 2-year-old hip prosthesis infected by Candida glabrata dose-dependent susceptible to fluconazole and voriconazole. Resection arthroplasty was performed. Six weeks of caspofungin plus liposomal amphotericin combination therapy achieved joint sterilization and allowed a successfully reimplantation arthroplasty. In addition we review 9 cases of C. glabrata prosthetic joint infection described to date in the literature.

  13. Hip arthroplasty by matching cups.

    PubMed

    Gerard, Y

    1978-01-01

    A total hip surface arthroplasty consisting of matching cups and uncemented prosthetic components is a noteworthy operation. The femoral cup obtains cylindrical support from the femoral head which is reamed in the shape of a cylinder. The acetabular cup is metallic with a polyethylene liner. It is mobile over the bone but its position is constrained by contact with the femoral cup and therefore "self-centering." On the femoral side, the cup must be placed strictly in the axis of the femoral neck. The main consideration in femoral head surface replacement is the vitality of the underlying bone. Necrosis was observed in the earliest clinical trials but there have been no cases of necrosis in the past 3 1/2 years. This is attributed to a more limited surgical approach in which only the anterior part of the gluteus medius is divided and all the posterior elements of the hip are preserved. The acetabulum is sufficiently reamed to receive the cup, which protrudes beyond the external margins of the acetabulum in all positions. Errors have been committed while perfecting the prosthetic material, but the results as determined by a 6 1/2 year follow-up on purely metallic cups are encouraging. Metal-polyethylene cups presently under investigation have almost a 2 year follow-up. The reaction of the acetabulum to an uncemented cup is not yet known. However, the existence of 2 sliding surfaces and the fact that the acetabular cup moves only during the extremes of hip movement, is reason to assume that if the acetabulum is not reamed to expose cancellous bone, the risks of protrusion are minimal or delayed. Total surface arthroplasty by concentric cups has been performed in 335 hips to date. The operation is especially recommended when osteotomy is no longer possible and disabling coxarthrosis is present in relatively young patients. PMID:729253

  14. Measurement outcomes from hip simulators.

    PubMed

    de Villiers, Danielle; Shelton, Julia C

    2016-05-01

    Simulation of wear in total hip replacements has been recognised as an important factor in determining the likelihood of clinical success. However, accurate measurement of wear can be problematic with factors such as number and morphology of wear particles produced as well as ion release proving more important in the biological response to hip replacements than wear volume or wear rate alone. In this study, hard-on-hard (CoCr alloy, AgCrN coating) and hard-on-soft (CoCr alloy and CrN coating on vitamin E blended highly cross-linked polyethylene) bearing combinations were tested in an orbital hip simulator under standard and some adverse conditions. Gravimetric wear rates were determined for all bearings, with cobalt and where applicable, silver release determined throughout testing. Isolation of wear particles from the lubricating fluid was used to determine the influence of different bearing combinations and wear conditions on particle morphology. It was found that cobalt and silver could be measured in the lubricating fluid even when volumetric wear was not detectable. In hard-on-hard bearings, Pearson's correlation of 0.98 was established between metal release into the lubricating fluid and wear volume. In hard-on-soft bearings, coating the head did not influence the polyethylene wear rates measured under standard conditions but did influence the cobalt release; the diameter influenced both polyethylene wear and cobalt release, and the introduction of adverse testing generated smaller polyethylene particles. While hip simulators can be useful to assess the wear performance of a new material or design, measurement of other outcomes may yield greater insight into the clinical behaviour of the bearings in vivo. PMID:26888886

  15. Resurfacing history of the northern plains of Mars based on geologic mapping of Mars Global Surveyor data

    USGS Publications Warehouse

    Tanaka, K.L.; Skinner, J.A.; Hare, T.M.; Joyal, T.; Wenker, A.

    2003-01-01

    Geologic mapping of the northern plains of Mars, based on Mars Orbiter Laser Altimeter topography and Viking and Mars Orbiter Camera images, reveals new insights into geologic processes and events in this region during the Hesperian and Amazonian Periods. We propose four successive stages of lowland resurfacing likely related to the activity of near-surface volatiles commencing at the highland-lowland boundary (HLB) and progressing to lower topographic levels as follows (highest elevations indicated): Stage 1, upper boundary plains, Early Hesperian, <-2.0 to -2.9 km; Stage 2, lower boundary plains and outflow channel dissection, Late Hesperian, <-2.7 to -4.0 km; Stage 3, Vastitas Borealis Formation (VBF) surface, Late Hesperian to Early Amazonian, <-3.1 to -4.1 km; and Stage 4, local chaos zones, Early Amazonian, <-3.8 to -5.0 km. At Acidalia Mensa, Stage 2 and 3 levels may be lower (<-4.4 and -4.8 km, respectively). Contractional ridges form the dominant structure in the plains and developed from near the end of the Early Hesperian to the Early Amazonian. Geomorphic evidence for a northern-plains-filling ocean during Stage 2 is absent because one did not form or its evidence was destroyed by Stage 3 resurfacing. Remnants of possible Amazonian dust mantles occur on top of the VBF. The north polar layered deposits appear to be made up of an up to kilometer-thick lower sequence of sandy layers Early to Middle Amazonian in age overlain by Late Amazonian ice-rich dust layers; both units appear to have outliers, suggesting that they once were more extensive.

  16. Pulsed and scanned carbon dioxide laser resurfacing 2 years after treatment: comparison by means of scanning electron microscopy.

    PubMed

    Trelles, Mario A; Garcia, Luisa; Rigau, Josepa; Allones, Inès; Velez, Marìano

    2003-05-01

    Studies have reported short-term and long-term (1-year) findings for laser skin resurfacing. Two of the most popular systems used for this procedure, the continuous-wave Sharplan 40C SilkTouch system and the pulsed Coherent 5000C UltraPulse system with a computer pattern generator, were previously compared for a range of follow-up times up to 1 year, using light microscopy and transmission electron microscopy. This study analyzed the 2-year morphological differences using scanning electron microscopy. Tissue samples were obtained from 10 patients (age range, 50 to 72 years; skin types II and III) who had undergone laser resurfacing 2 years previously. One half of the face of each patient had been treated with the continuous-wave system and the other half with the pulsed system. The samples were subjected to scanning electron microscopy. On the continuous-wave-treated side, significantly better dermal collagen organization was observed at 2 years, with plump-appearing fibers that were closely knit to form a compact structure. On the side treated with the pulsed system, the collagen fibers in the papillary dermis were more loosely arranged and appeared drier. In both the continuous-wave-treated and pulsed-treated areas, the epidermis appeared healthy and exhibited some signs of age-related deterioration, with slightly flatter plaques and somewhat more flaking keratin on the pulsed-treated side. Probably because of the greater degree of residual thermal damage associated with the continuous-wave system, at 2 years after treatment there was more prolific synthesis and better orientation of collagen fibers, which were maintained for longer times, compared with the pulsed-treated specimens.

  17. Congenital Dislocation of the Hip

    PubMed Central

    Specht, Elmer E.

    1976-01-01

    Congenital dislocation or subluxation of the hip (congenital acetabular dysplasia) is a complete or partial displacement of the femoral head out of the acetabulum. The physical signs essential for diagnosis are age related. In newborns the tests for instability are the most sensitive. After the neonatal period, and until the age of walking, tightness of the adductor muscles is the most reliable sign. Early diagnosis is vital for successful treatment of this partially genetically determined condition. Various therapeutic measures, ranging from abduction splinting to open reduction and osteotomy, may be required. Following diagnosis in the first month of life, the average treatment time in one recent series was only 2.3 months from initiation of therapy to attainment of a normal hip. When the diagnosis was not made until 3 to 6 months of age, ten months of treatment was required to achieve the same outcome. When the diagnosis is not made, or the treatment is not begun until after the age of 6, a normal hip will probably not develop in any patient. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6.Figure 7.Figure 8.Figure 9. PMID:1251603

  18. A Hip Implant Energy Harvester

    NASA Astrophysics Data System (ADS)

    Pancharoen, K.; Zhu, D.; Beeby, S. P.

    2014-11-01

    This paper presents a kinetic energy harvester designed to be embedded in a hip implant which aims to operate at a low frequency associated with body motion of patients. The prototype is designed based on the constrained volume available in a hip prosthesis and the challenge is to harvest energy from low frequency movements (< 1 Hz) which is an average frequency during free walking of a patient. The concept of magnetic-force-driven energy harvesting is applied to this prototype considering the hip movements during routine activities of patients. The magnetic field within the harvester was simulated using COMSOL. The simulated resonant frequency was around 30 Hz and the voltage induced in a coil was predicted to be 47.8 mV. A prototype of the energy harvester was fabricated and tested. A maximum open circuit voltage of 39.43 mV was obtained and the resonant frequency of 28 Hz was observed. Moreover, the power output of 0.96 μW was achieved with an optimum resistive load of 250Ω.

  19. Cover Story: The Miseducation of Hip-Hop.

    ERIC Educational Resources Information Center

    Evelyn, Jamilah

    2000-01-01

    Some higher education officials believe that hip-hop music is eating away at the morals, and ultimately the classroom experience, of today's college students. Discusses why the gap exists between student and faculty attitudes toward hip-hop, how hip-hop music represents blackness, how people perceive hip-hop youth, the positive side of hip-hop,…

  20. RSA wear measurements with or without markers in total hip arthroplasty.

    PubMed

    Börlin, Niclas; Röhrl, Stephan M; Bragdon, Charles R

    2006-01-01

    Novel algorithms for radiostereometric (RSA) measurements of the femoral head and metal-backed, hemi-spherical cups of a total hip replacement are presented and evaluated on phantom images and clinical double examinations of 20 patients. The materials were analysed with classical RSA and three novel algorithms: (1) a dual-projection head algorithm using the outline of the femoral head together with markers in the cup; (2) a marker-less algorithm based on measurements of the outline of the femoral head, the cup shell and opening circle of the cup; and (3) a combination of both methods. The novel algorithms improve current, marker-based, RSA measurements, as well as allows studies without marked cups. This opens the possibility of performing wear measurements on larger group of patients, in clinical follow-ups, even retrospective studies. The novel algorithms may help to save patient data in current RSA studies lost due to insufficiently marked cups. Finally, the novel algorithms simplify the RSA procedure and allow new studies without markers, saving time, money, and reducing safety concerns. Other potential uses include migration measurements of re-surfacing heads and measuring spherical sections as implant landmarks instead of markers.

  1. Posterior Hip Pain in an Athletic Population

    PubMed Central

    Frank, Rachel M.; Slabaugh, Mark A.; Grumet, Robert C.; Virkus, Walter W.; Bush-Joseph, Charles A.; Nho, Shane J.

    2010-01-01

    Context: Posterior hip pain is a relatively uncommon but increasingly recognized complaint in the orthopaedic community. Patient complaints and presentations are often vague or nonspecific, making diagnosis and subsequent treatment decisions difficult. The purposes of this article are to review the anatomy and pathophysiology related to posterior hip pain in the athletic patient population. Evidence Acquisition: Data were collected through a thorough review of the literature via a MEDLINE search of all relevant articles between 1980 and 2010. Results: Many patients who complain of posterior hip pain actually have pain referred from another part of the body—notably, the lumbar spine or sacroiliac joint. Treatment options for posterior hip pain are typically nonoperative; however, surgery is warranted in some cases. Conclusions: Recent advancements in the understanding of hip anatomy, pathophysiology, and treatment options have enabled physicians to better diagnosis athletic hip injuries and select patients for appropriate treatment. PMID:23015944

  2. Hip involvement in early rheumatoid arthritis.

    PubMed Central

    Eberhardt, K; Fex, E; Johnsson, K; Geborek, P

    1995-01-01

    OBJECTIVE--To study early hip involvement in rheumatoid arthritis (RA) and to evaluate the usefulness of ultrasonography in the detection of hip joint synovitis in RA. METHODS--Study I: The number of hip joint replacements was recorded in a cohort of 113 patients with RA of at least five years disease duration followed from an early stage. Study II: Ultrasonography was evaluated as a method to identify hip joint synovitis in 76 patients with RA of shorter disease duration, by relating it to radiograms and clinical findings. RESULTS--Study I: Twenty one hip joint replacements were performed in 15 of the 113 patients. The median disease duration at the time of first arthroplasty was 48 (range 10-76) months; the annual incidence was approximately constant between two and six years. High disease activity at the start of the study was predictive of requirement for hip prosthesis. Study II: Hip ultrasonography was pathological in 13 of the 76 patients studied, bilaterally in nine. Hip joint synovitis could not be confirmed on clinical grounds only as seven of the patients with positive ultrasonographic findings were asymptomatic, and the remaining six patients had only mild symptoms of hip involvement. Also, six of the 63 patients with normal ultrasonography had mild symptoms. There was no difference regarding demographic, clinical, and laboratory findings in patients with and without hip synovitis. CONCLUSIONS--Early hip joint destruction giving symptoms mostly at a very late stage is frequent in RA. Ultrasonography rather than signs or symptoms could identify patients with hip joint involvement and provide a rationale for early treatment. Images PMID:7880121

  3. Pelvic Incidence in Patients with Hip Osteoarthritis

    PubMed Central

    Raphael, Ibrahim J.; Rasouli, Mohammad R.; Kepler, Christopher K.; Restrepo, Santiago; Albert, Todd J.; Radcliff, Kris E.

    2016-01-01

    Background: Hip osteoarthritis (OA) is a major cause of pain and disability that results in considerable social and medical costs. Mechanics such as posture, alignment and orientation of the hips and the spinal column and the relationship between these factors have been implicated in the development of both hip and spine pathologies. This study aims to test the hypothesis if pelvic incidence varies in patients with and without osteoarthritis. We assessed the relationship between spinopelvic alignment as measured by pelvic incidence (PI) and the presence of hip OA. Methods: We collected supine pelvis CT scans of 1,012 consecutive patients not known to have hip OA. Our first group consisted of 95 patients with moderate to severe hip OA as per radiology reports. The second group included 87 patients with no evidence of hip OA. Power analysis revealed the need for 77 patients per group to find a mean difference in PI of 5° or less between both groups. Two trained physicians independently measured the PI to account for inter-observer reliability. Results: Patients with moderate to severe hip OA had a mean PI of 56.5°±12.8°. The mean PI for patients without hip OA was 57.2°±7.5°. An independent samples t-test revealed no significant difference between the PI values of the two groups. Spearman’s correlation coefficient of 0.754 demonstrated a high inter-observer reliability. Conclusion: There was no difference in PI angle of hip OA patients and “healthy” patients. Our measurements of patients without OA were almost identical to the reported normal PI values in the literature. It appears that hip OA is not associated with PI angle, refuting the hypothesis made in previous studies, stating that elevated PI contributes to the future development of hip arthritis. CT scan seems to be a reliable and accurate way of assessing pelvic incidence. PMID:27200390

  4. Life Estimation of Hip Joint Prosthesis

    NASA Astrophysics Data System (ADS)

    Desai, C.; Hirani, H.; Chawla, A.

    2014-11-01

    Hip joint is one of the largest weight-bearing structures in the human body. In the event of a failure of the natural hip joint, it is replaced with an artificial hip joint, known as hip joint prosthesis. The design of hip joint prosthesis must be such so as to resist fatigue failure of hip joint stem as well as bone cement, and minimize wear caused by sliding present between its head and socket. In the present paper an attempt is made to consider both fatigue and wear effects simultaneously in estimating functional-life of the hip joint prosthesis. The finite element modeling of hip joint prosthesis using HyperMesh™ (version 9) has been reported. The static analysis (load due to the dead weight of the body) and dynamic analysis (load due to walking cycle) have been described. Fatigue life is estimated by using the S-N curve of individual materials. To account for progressive wear of hip joint prosthesis, Archard's wear law, modifications in socket geometry and dynamic analysis have been used in a sequential manner. Using such sequential programming reduction in peak stress has been observed with increase in wear. Finally life is estimated on the basis of socket wear.

  5. International variation in hip replacement rates

    PubMed Central

    Merx, H; Dreinhofer, K; Schrader, P; Sturmer, T; Puhl, W; Gunther, K; Brenner, H

    2003-01-01

    Objectives: To summarise epidemiological data on the frequency of hip replacements in the countries of the developed world, especially in countries of the Organisation for Economic Cooperation and Development (OECD), and to investigate whether missing consensus criteria for the indication for total hip replacement (THR) result in different replacement rates. Methods: Country-specific hip replacement rates were collected using the available literature, different data sources of national authorities, and estimates of leading hip replacement manufacturers. Results: According to administrative and literature data sources the reported crude primary THR rate varied between 50 and 130 procedures/100 000 inhabitants in OECD countries in the 1990s. The crude overall hip implantation rate, summarising THR, partial hip replacement, and hip revision procedures, was reported to range from 60 to 200 procedures/100 000 inhabitants in the late 1990s. Moreover, large national differences were seen in the relationship between total and partial hip replacement procedures. Conclusion: The reported differences in hip replacement rates in OECD countries are substantial. They may be due to various causes, including different coding systems, country-specific differences in the healthcare system, in total expenditure on health per capita, in the population age structure, and in different indication criteria for THR. PMID:12594106

  6. Surgical hip dislocation: techniques for success.

    PubMed

    Ricciardi, Benjamin F; Sink, Ernest L

    2014-01-01

    Surgical hip dislocation (SHD) is a versatile approach used to address both intra-articular and extra-articular pathology around the hip joint in both pediatric and adult patients. It allows anterior dislocation of the femoral head for direct visualization of the hip joint while preserving femoral head vascularity and minimizing trauma to the abductor musculature. Previously described indications for SHD include femoroacetabular impingement, deformity resulting from Legg-Calve-Perthes disease, slipped capital femoral epiphysis, periarticular trauma, benign lesions of the hip joint, and osteochondral lesions. In this review, we will describe current surgical techniques, indications, and clinical outcomes for SHD. PMID:25207733

  7. Burnishing Techniques Strengthen Hip Implants

    NASA Technical Reports Server (NTRS)

    2010-01-01

    In the late 1990s, Lambda Research Inc., of Cincinnati, Ohio, received Small Business Innovation Research (SBIR) awards from Glenn Research Center to demonstrate low plasticity burnishing (LPB) on metal engine components. By producing a thermally stable deep layer of compressive residual stress, LPB significantly strengthened turbine alloys. After Lambda patented the process, the Federal Aviation Administration accepted LPB for repair and alteration of commercial aircraft components, the U.S. Department of Energy found LPB suitable for treating nuclear waste containers at Yucca Mountain. Data from the U.S. Food and Drug Administration confirmed LPB to completely eliminate the occurrence of fretting fatigue failures in modular hip implants.

  8. Infection after primary hip arthroplasty

    PubMed Central

    2011-01-01

    Background and purpose The aim of the present study was to assess incidence of and risk factors for infection after hip arthroplasty in data from 3 national health registries. We investigated differences in risk patterns between surgical site infection (SSI) and revision due to infection after primary total hip arthroplasty (THA) and hemiarthroplasty (HA). Materials and methods This observational study was based on prospective data from 2005–2009 on primary THAs and HAs from the Norwegian Arthroplasty Register (NAR), the Norwegian Hip Fracture Register (NHFR), and the Norwegian Surveillance System for Healthcare–Associated Infections (NOIS). The Norwegian Patient Register (NPR) was used for evaluation of case reporting. Cox regression analyses were performed with revision due to infection as endpoint for data from the NAR and the NHFR, and with SSI as the endpoint for data from the NOIS. Results The 1–year incidence of SSI in the NOIS was 3.0% after THA (167/5,540) and 7.3% after HA (103/1,416). The 1–year incidence of revision due to infection was 0.7% for THAs in the NAR (182/24,512) and 1.5% for HAs in the NHFR (128/8,262). Risk factors for SSI after THA were advanced age, ASA class higher than 2, and short duration of surgery. For THA, the risk factors for revision due to infection were male sex, advanced age, ASA class higher than 1, emergency surgery, uncemented fixation, and a National Nosocomial Infection Surveillance (NNIS) risk index of 2 or more. For HAs inserted after fracture, age less than 60 and short duration of surgery were risk factors of revision due to infection. Interpretation The incidences of SSI and revision due to infection after primary hip replacements in Norway are similar to those in other countries. There may be differences in risk pattern between SSI and revision due to infection after arthroplasty. The risk patterns for revision due to infection appear to be different for HA and THA. PMID:22066562

  9. HIP Joining of Cemented Carbides

    SciTech Connect

    Derby, B.; Miodownik, M.

    1999-04-01

    Hot Isostatic Pressing (HIP) is investigated as a technique for joining the cermet WC-15% Co to itself. Encapsulation of the specimens prior to HIPing was carried out using steel encapsulation, glass encapsulation and self encapsulation. The bonds were evaluated using a four point bend method. It is shown that the glass and steel encapsulation methods have a number of inherent problems which make them inappropriate for near net shape processing. In contrast the novel self encapsulation method, described for the first time in this communication, is both simple and effective, producing joined material with bulk strength. The concept of self encapsulation is potentially widely applicable for joining composite materials.

  10. Making A Noble-Metal-On-Metal-Oxide Catalyst

    NASA Technical Reports Server (NTRS)

    Miller, Irvin M.; Davis, Patricia P.; Upchurch, Billy T.

    1989-01-01

    Catalyst exhibits superior performance in oxidation of CO in CO2 lasers. Two-step process developed for preparing platinum- or palladium-on-tin-oxide catalyst for recombination of CO and O2, decomposition products that occur in high-voltage discharge region of closed-cycle CO2 laser. Process also applicable to other noble-metal/metal-oxide combinations.

  11. Metal-On-Metal Bonding and Rebonding Revisited

    SciTech Connect

    Bogicevic, A.

    1999-02-23

    Density-functional calculations for a wide variety of metals show that, contrary to the rebonding view of adsorbate bonding, addimers do not have notably longer surface bonds than adatoms, do not reside farther above the surface, and do not meet the rebonding arguments for augmented mobility. Rebonding concepts are found to have some utility in explaining addimer stability.

  12. Implant Design in Cementless Hip Arthroplasty

    PubMed Central

    Kim, Jung Taek

    2016-01-01

    When performing cementless hip arthroplasty, it is critical to achieve firm primary mechanical stability followed by biological fixation. In order to achieve this, it is essential to fully understand characteristics of implant design. In this review, the authors review fixation principles for a variety of implants used for cementless hip replacement and considerations for making an optimal selection. PMID:27536647

  13. Process for HIP canning of composites

    NASA Technical Reports Server (NTRS)

    Juhas, John J. (Inventor)

    1990-01-01

    A single step is relied on in the canning process for hot isostatic pressing (HIP) metallurgy composites. The composites are made from arc sprayed and plasma sprayed monotape. The HIP can is of compatible refractory metal and is sealed at high vacuum and temperature. This eliminates outgassing during hot isostatic pressing.

  14. Hip Arthroscopy: Tales From the Crypt.

    PubMed

    Matsuda, Dean K; Philippon, Marc J; Safran, Marc R; Sampson, Thomas G

    2016-01-01

    Complications after hip arthroscopy vary in frequency and severity, even for experienced surgeons. It is important for surgeons to be aware of some of the more dramatic, often unusual, and always memorable (nightmarish) complications of hip arthroscopy and understand how they are caused, how they can be treated, and how they can be prevented.

  15. Hip Arthroscopy: Tales From the Crypt.

    PubMed

    Matsuda, Dean K; Philippon, Marc J; Safran, Marc R; Sampson, Thomas G

    2016-01-01

    Complications after hip arthroscopy vary in frequency and severity, even for experienced surgeons. It is important for surgeons to be aware of some of the more dramatic, often unusual, and always memorable (nightmarish) complications of hip arthroscopy and understand how they are caused, how they can be treated, and how they can be prevented. PMID:27049210

  16. Sonography of Sports Injuries of the Hip

    PubMed Central

    Dawes, Aaron R. L.; Seidenberg, Peter H.

    2014-01-01

    Context: Sports-related injuries of the hip are a common complaint of both competitive and recreational athletes of all ages. The anatomic and biomechanical complexity of the hip region often cause diagnostic uncertainty for the clinicians evaluating these injuries. Therefore, obtaining additional diagnostic information is often crucial for providing injured athletes with a prompt and accurate diagnosis so they can return to activity as soon as possible. Musculoskeletal ultrasound is becoming increasingly important in evaluating and treating sports-related injuries of the hip. Evidence Acquisition: The PubMed database was searched in May of 2013 for English-language articles pertaining to sonography of sports injuries of the hip using the following keywords in various combinations: musculoskeletal, ultrasound, hip, hip sonography, and sports. Study Design: Clinical review. Level of Evidence: Level 4. Results: Musculoskeletal ultrasound is currently being used for both diagnosis and treatment in a wide range of acute and chronic conditions affecting the hip, including tendinosis, tendon/muscle strains, ligamentous sprains, enthesopathies, growth plate injuries, fractures, bursitis, effusions, synovitis, labral tears, and snapping hip. Therapeutically, it is used to guide injections, aspirations, and biopsies. Conclusion: Musculoskeletal ultrasound use is expanding and will likely continue to do so as more clinicians realize its capabilities. Characteristics, including accessibility, portability, noninvasiveness, dynamic examination, power Doppler examination, and low cost highlight the potential of ultrasound. PMID:25364486

  17. Asymmetric Hip Rotation in Professional Baseball Pitchers

    PubMed Central

    McCulloch, Patrick C.; Patel, Jayesh K.; Ramkumar, Prem N.; Noble, Philip C.; Lintner, David M.

    2014-01-01

    Background: There is a renewed interest in examining the association between hip range of motion and injury in athletes, and the data on baseball players are conflicting. Understanding whether asymmetrical hip rotation is a normal adaptation or a risk factor for injury will help therapists, trainers, and physicians develop rehabilitation programs to improve kinetic energy transfer and prevent injury. As our knowledge of hip pathology among baseball pitchers improves, establishing baselines for hip motion is critical in the further assessment of injury. Hypothesis: Because of the repetitive nature of throwing sports and the adaptive changes documented in the shoulder, elite baseball pitchers would have characteristic patterns of hip internal and external rotations on their dominant throwing side (stance) and their nondominant side (stride) in extension. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Computer software was used to measure passive internal and external rotations on digital photographs of 111 professional baseball pitchers. Results: In right-handed pitchers, there was significantly more internal rotation in the stance hip than the stride hip (32.2° ± 8.2° vs 30.8° ± 8.4°; P = .0349) and significantly more external rotation in the stride hip than the stance hip (36.3° ± 7.7° vs 30.8° ± 9.7°; P < .0001). While the mean difference in external rotation was 4.7°, 32% of the subjects had a >10° increase in external rotation on the stride hip relative to the stance hip. This population was statistically different from the remaining group for older age (P = .0053), lower body mass index (P = .0379), and more years in professional baseball (P = .0328). In the smaller number of left-handed pitchers, side-to-side differences in hip rotation were found but were not statistically significant. Conclusion: Pitchers showed more internal rotation on their stance hip and more external rotation on their stride hip. Although the mean

  18. Auditing hip ultrasound screening of infants at increased risk of developmental dysplasia of the hip

    PubMed Central

    Lowry, C; Donoghue, V; Murphy, J

    2005-01-01

    Background: Clinical examination, while useful, has been shown to be insufficient as the sole screening method in infants. Ultrasound examination at 8 weeks in high risk infants is an integral part of the screening process in some units. Aims: To show the efficiency of hip sonography in detection of developmental dysplasia of the hips in those without clinically dislocated hips. Methods: All infants born at the National Maternity Hospital between January 1994 and December 2001 were included. All those with clinically dislocated hips were treated by a Pavlik harness and referred for follow up to a paediatric orthopaedic surgeon. An 8 week hip ultrasound scan was performed for those infants with stable hips on examination but who met the following criteria: (1) a first degree relative with congenital dislocation of hips; (2) breech presentation at birth; and (3) a persistent "click" at birth in an otherwise stable hip. Results: During the period of study a total of 52 893 infants were born in the National Maternity Hospital. Based on the criteria above, 5485 hip ultrasound scans were performed. Of those scanned, 18 (0.33%) were found to have dislocated hips and 153 (2.78%) to have dysplasic hips. The 18 infants with dislocation were treated with Pavlik harness; the remaining 153 were followed up by serial ultrasound examinations but did not require active intervention. Conclusions: Among the population of infants at increased risk of developmental dysplasia of the hip, the hip screening programme identified 18 cases among 5485 infants; a rate of 3.2 per 1000. Hip sonography is therefore worthwhile. PMID:15908620

  19. Persons with Chronic Hip Joint Pain Exhibit Reduced Hip Muscle Strength

    PubMed Central

    Mueller, Michael J.; Sahrmann, Shirley A.; Bloom, Nancy J.; Steger-May, Karen; Clohisy, John C.; Salsich, Gretchen B.

    2014-01-01

    STUDY DESIGN Controlled Laboratory Cross-Sectional Study OBJECTIVES To assess strength differences of the hip rotator and abductor muscle groups in young adults with chronic hip joint pain (CHJP) and asymptomatic controls. A secondary objective was to determine if strength in the uninvolved hip of those with unilateral CHJP differs from asymptomatic controls. BACKGROUND Little is known about the relationship between hip muscle strength and CHJP in young adults. METHODS 35 participants with CHJP and 35 matched controls (18 to 40 years of age) participated. Using hand-held dynamometry, strength of the hip external rotators (ERs) and internal rotators (IRs) was assessed with the hip flexed to 90° (ERs90°, IRs90°) and 0° (ERs0°, IRs0°). To assess ER and IR strength, the hip was placed at the end-range of external rotation and internal rotation, respectively. Strength of the hip abductors (ABDs) was assessed in sidelying, with the hip in 15° of abduction. Break tests were performed to determine maximum muscle force and the average torque was calculated using the corresponding moment arm. Independent samples t-tests were used to compare strength values between the 1) involved limb in participants with CHJP and corresponding limb in the matched controls and 2) the uninvolved limb in participants with unilateral CHJP and corresponding limb in the matched controls. RESULTS Compared to controls, participants with CHJP demonstrated weakness of 16–28%, (P<0.01) in all muscle groups tested in the involved hip. The uninvolved hip of 22 subjects with unilateral CHJP demonstrated weakness of 18% and 16% (P<0.05) in the ERs0° and ABDs, respectively when compared to the corresponding limb of the matched controls. CONCLUSION Our results demonstrate that persons with CHJP have weakness in the hip rotator and hip abductor muscles. Weakness also was found in the uninvolved hip of persons with CHJP. PMID:25299750

  20. Rehabilitation of the hip following sports injury.

    PubMed

    Tyler, Timothy F; Slattery, Aimee A

    2010-01-01

    An athlete often presents to the rehabilitation specialist with either a nonspecific referral, such as "hip pain," or with a diagnosis of a more specific hip pathology. The highly skilled clinician is trained to look at the "linkage" between the trunk and all parts of the lower extremity. Why is the hip not transferring the load well? Where is the breakdown? The gluteus medius, pelvic stability, and supportive muscular slings are of great importance when optimizing the function of the hip. The hip is subjected to forces equal to multiples of the body weight and requires osseous, articular and myofascial integrity for stability. This is the mind set when devising an athlete's rehabilitative program, looking at all influential factors that affect joint movement and integrity.

  1. Unstable total hip arthroplasty: detailed overview.

    PubMed

    Berry, D J

    2001-01-01

    Hip dislocation is one of the most common complications of THA. Good preoperative planning, good postoperative patient education, accurate intraoperative component positioning, rigorous intraoperative testing of hip stability, and good repair of soft tissues during closure all help prevent dislocation. Early postoperative dislocations and first or second dislocations usually are treated with closed reduction and a hip guide brace or hip spica cast, but when dislocation becomes recurrent, surgical treatment usually is needed. When possible, surgical treatment is based on identifying and treating a specific problem leading to the dislocation, such as implant malposition, inadequate soft-tissue tension, or impingement. In selected circumstances, constrained implants or bipolar or tripolar implants provide powerful tools to restore hip stability.

  2. Implant based differences in adverse local tissue reaction in failed total hip arthroplasties: a morphological and immunohistochemical study

    PubMed Central

    2014-01-01

    Background Adverse local tissue reaction (ALTR) is characterized by periprosthetic soft tissue inflammation composed of a mixed inflammatory cell infiltrate, extensive soft tissue necrosis, and vascular changes. Multiple hip implant classes have been reported to result in ALTR, and clinical differences may represent variation in the soft tissue response at the cellular and tissue levels. The purpose of this study was to describe similarities and differences in periprosthetic tissue structure, organization, and cellular composition by conventional histology and immunohistochemistry in ALTR resulting from two common total hip arthroplasty (THA) implant classes. Methods Consecutive patients presenting with ALTR from two major hip implant classes (N = 54 patients with Dual-Modular Neck implant; N = 14 patients with Metal-on-Metal implant) were identified from our prospective Osteolysis Tissue Database and Repository. Clinical characteristics including age, sex, BMI, length of implantation, and serum metal ion levels were recorded. Retrieved synovial tissue morphology was graded using light microscopy and cellular composition was assessed using immunohistochemistry. Results Length of implantation was shorter in the DMN group versus MoM THA group (21.3 [8.4] months versus 43.6 [13.8] months respectively; p < 0.005) suggesting differences in implant performance. Morphologic examination revealed a common spectrum of neo-synovial proliferation and necrosis in both groups. Macrophages were more commonly present in diffuse sheets (Grade 3) in the MoM relative to DMN group (p = 0.016). Perivascular lymphocytes with germinal centers (Grade 4) were more common in the DMN group, which trended towards significance (p = 0.066). Qualitative differences in corrosion product morphology were seen between the two groups. Immunohistochemistry showed features of a CD4 and GATA-3 rich lymphocyte reaction in both implants, with increased ratios of perivascular T

  3. Large-diameter total hip arthroplasty modular heads require greater assembly forces for initial stability

    PubMed Central

    MacLeod, A. R.; Sullivan, N. P. T.; Whitehouse, M. R.

    2016-01-01

    Objectives Modular junctions are ubiquitous in contemporary hip arthroplasty. The head-trunnion junction is implicated in the failure of large diameter metal-on-metal (MoM) hips which are the currently the topic of one the largest legal actions in the history of orthopaedics (estimated costs are stated to exceed $4 billion). Several factors are known to influence the strength of these press-fit modular connections. However, the influence of different head sizes has not previously been investigated. The aim of the study was to establish whether the choice of head size influences the initial strength of the trunnion-head connection. Materials and Methods Ti-6Al-4V trunnions (n = 60) and two different sizes of cobalt-chromium (Co-Cr) heads (28 mm and 36 mm; 30 of each size) were used in the study. Three different levels of assembly force were considered: 4 kN; 5 kN; and 6 kN (n = 10 each). The strength of the press-fit connection was subsequently evaluated by measuring the pull-off force required to break the connection. The statistical differences in pull-off force were examined using a Kruskal–Wallis test and two-sample Mann–Whitney U test. Finite element and analytical models were developed to understand the reasons for the experimentally observed differences. Results 36 mm diameter heads had significantly lower pull-off forces than 28 mm heads when impacted at 4 kN and 5 kN (p < 0.001; p < 0.001), but not at 6 kN (p = 0.21). Mean pull-off forces at 4 kN and 5 kN impaction forces were approximately 20% larger for 28 mm heads compared with 36 mm heads. Finite element and analytical models demonstrate that the differences in pull-off strength can be explained by differences in structural rigidity and the resulting interface pressures. Conclusion This is the first study to show that 36 mm Co-Cr heads have up to 20% lower pull-off connection strength compared with 28 mm heads for equivalent assembly forces. This effect is likely

  4. Reconstruction of the Acetabulum in Developmental Dysplasia of the Hip in total hip replacement.

    PubMed

    Sakellariou, Vasileios I; Christodoulou, Michael; Sasalos, Gregory; Babis, George C

    2014-09-01

    Developmental dysplasia of the hip (DDH) or congenital hip dysplasia (CDH) is the most prevalent developmental childhood hip disorder. It includes a wide spectrum of hip abnormalities ranging from dysplasia to subluxation and complete dislocation of the hip joint. The natural history of neglected DDH in adults is highly variable. The mean age of onset of symptoms is 34.5 years for dysplastic DDH, 32.5 years for low dislocation, 31.2 years for high dislocation with a false acetabulum, and 46.4 years for high dislocation without a false acetabulum. Thorough understanding of the bony and soft tissue deformities induced by dysplasia is crucial for the success of total hip arthroplasty. It is important to evaluate the existing acetabular deformity three-dimensionally, and customize the correction in accordance with the quantity and location of ace tabular deficiencies. Acetabular reconstruction in patients with DDH is challenging. Interpretation of published data is difficult and should be done with caution because most series include patients with different types of hip disease. In general, the complication rate associated with THA is higher in patients with hip dysplasia than it is in patients with osteoarthritis. Overall, clinical and functional outcomes following THA in patients hip dysplasia (DDH) differ from those treated for primary hip osteoarthritis, possibly due to the lower age and level of activity. Although function scores decline with age, the scores for pain and range of motion presented with a statistically significant improvement in the long-term. PMID:25386570

  5. Revision of minimal resection resurfacing unicondylar knee arthroplasty to total knee arthroplasty: results compared with primary total knee arthroplasty.

    PubMed

    O'Donnell, Turlough M P; Abouazza, Omar; Neil, Michael J

    2013-01-01

    We compared a cohort of patients undergoing revision of a minimal resection resurfacing unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA) with a cohort of patients undergoing primary TKA. Both cohorts were matched in terms of age, sex, and body mass index. We collected data on preoperative and postoperative range of motion, International Knee Society scores, and radiologic data. We also collected data on the modes of failure of the primary UKA. There were 55 patients in each cohort. The average time the UKA was in place was 48.3 months. The average follow-up period from the time of revision was 39.2 months. The most common reason for revision was subsidence of the tibial base plate (58%). Forty percent of patients required particulate bone grafting for contained defects. Two patients required metal augments, and 1 required stems. There was no significant difference between the 2 groups in terms of range of motion, functional outcome, or radiologic outcomes. Revision of these types of implants to TKA is associated with similar results to primary TKA and is superior to revision of other forms of UKA.

  6. Iron isotopic evidence for convective resurfacing of recycled arc-front mantle beneath back-arc basins

    NASA Astrophysics Data System (ADS)

    Nebel, O.; Arculus, R. J.; Sossi, P. A.; Jenner, F. E.; Whan, T. H. E.

    2013-11-01

    observations suggest sub-arc convective flow transports melt-exhausted and metasomatized wedge mantle into deeper mantle regions. Reciprocally, asthenospheric, fertile mantle may supply back-arc ridges distal to the trench by shallow, lateral mantle ingress, insinuating initial wedge mantle depletion in its back-arc region. Here we show that light Fe isotope compositions of the Central Lau Spreading Centre located in the Lau back-arc basin on the farside of the Tonga-Kermadec arc are indicative for derivation from a modified arc-front mantle with elemental and Nd-isotopic memory of former slab fluid addition. We propose that this shallow wedge material has been transported from the sub-arc mantle to the back-arc either convectively or in a buoyant diapir. This implies that melt-depleted mantle in subduction zones is, at least in parts, recycled in a resurfacing loop. This can explain the depletion in back-arc regions, and the progressively depleted nature of island arc sources in maturing arc systems.

  7. Epidemiology of osteoporotic hip fractures in Spain

    PubMed Central

    Martínez, Angel Antonio; Ferrandez, Luis; Gil, Enrique; Moreno, Alonso

    2005-01-01

    We conducted a multicentre study, divided into a retrospective and a prospective portion. The retrospective study evaluated osteoporotic hip fractures that occurred during 2002. The prospective study evaluated osteoporotic hip fractures that occurred during May 2003. The study was conducted in 77 hospitals in Spain and comprised patients 60 years of age and over. In the retrospective study we registered 13,195 hip fractures. Of the patients, 74% were women and 26% were men. The mean age was 80.7±8.4 years. The average incidence was 6.94±0.44 hip fractures per 1,000 inhabitants/year (95% CI, 6.07–7.82). In the prospective study, we registered 1,399 hip fractures. This represents a monthly incidence of 0.60±0.04 hip fractures per 1,000 inhabitants/year (95% CI, 0.51–0.69). Of the subjects, 74% were women and 26% were men. The mean age was 81.4±8.1 years. Using these data, we calculated the average annual prevalence in 2003 to be 7.20 fractures per 1,000 inhabitants. Thirty-three percent had previously suffered a hip fracture. Prior to the fracture, only 18% had received medical treatment for osteoporosis. After discharge from the hospital, only 26% were receiving pharmacological treatment for osteoporosis. PMID:16328387

  8. Mechanical Evaluation of Polymer Composite Hip Protectors

    PubMed Central

    Melo, Jose Daniel Diniz; Barbosa, Ayrles S. Gonçalves; Guerra, Ricardo Oliveira

    2010-01-01

    Hip fractures often result in serious health implications, particularly in the geriatric population, and have been related to long-term morbidity and death. In most cases, these fractures are caused by impact loads in the area of the greater trochanter, which are produced in a fall. This work is aimed at developing hip protectors using composite materials and evaluating their effectiveness in preventing hip fractures under high impact energy (120 J). The hip protectors were developed with an inner layer of energy absorbing soft material and an outer rigid shell of fiberglass-reinforced polymer composite. According to the experimental results, all tested configurations proved to be effective at reducing the impact load to below the average fracture threshold of proximal femur. Furthermore, an addition of Ethylene Vinyl Acetate (EVA) to the impacted area of the composite shell proved to be beneficial to increase impact strength of the hip protectors. Thus, composite hip protectors proved to be a viable alternative for a mechanically efficient and cost-effective solution to prevent hip fractures. PMID:20871841

  9. BLEEDING OF FEMORAL HEAD DURING TOTAL HIP ARTHROPLASTY FOR OSTEOARTHROSIS

    PubMed Central

    Schwartsmann, Carlos Roberto; Spinelli, Leandro de Freitas; Sotomayor, Marco Yánez; Yépez, Anthony Kerbes; Boschin, Leonardo Carbonera; Silva, Marcelo Faria

    2015-01-01

    ABSTRACT Objective: To evaluate the bleeding of the femoral head on hip osteoarthritis in patients who underwent total hip arthroplasty. Methods: One hundred and three hips affected by primary hip osteoarthritis were evaluated. After surgical dislocation, the femoral head was divided into four quadrants, and micro perforations were made in order to observe and assess the presence of bleeding, as early type (EB), late type (LB) or without bleeding (WB). Results: We observed early bleeding (EB) in the upper quadrant in 16 hips (15.5%), late bleeding in 14 hips (13.6%) and no bleeding (WB) in 73 hips (70.9%). The anterior quadrant showed EB in 24 hips (23.3%), LB in 7 hips (6.8%) and WB in 72 hips (69.9%). The lower quadrant presented EB in 40 hips (38.8%), LB 14 hips (13.6%) and WB in 49 hips (47.6%). The posterior quadrant showed EB in 39 hips (37.9%), LB 19 hips (18.4%) and WB in 45 hips (43.7%). Comparing BMI and gender, we found no association between these parameters (p> 0.05). Conclusions: The inferior and posterior quadrant had the highest bleeding levels, following the path of the medial circumflex artery. Level of Evidence III, Therapeutic Study. PMID:26981036

  10. [Dysplasia in the development of the hip].

    PubMed

    Moraleda, L; Albiñana, J; Salcedo, M; Gonzalez-Moran, G

    2013-01-01

    Developmental dysplasia of the hip (DDH) causes anatomical changes that cause early coxarthrosis. Although risf factors have been determined, the aetiology and physiopathology remains exactly unknown. Neonatal screening with physical examination and ultrasound have been stablished in order to diagnose this disease early in life. A diagnosis in the first months of life is essential as it enables a normal hip to form and prevent the appearance of early coxarthrosis. Treatment principles are to be able to reduce the hip without provoking avascular necrosis of the femoral head, and to normalize the acetabular development. Knowledge of the orthopaedic and surgical options is essential in order to achieve success in the treatment.

  11. Mesoderm Differentiation from hiPS Cells.

    PubMed

    Miwa, Hiroyuki; Era, Takumi

    2016-01-01

    Human induced pluripotent stem (hiPS) cells are very attractive tools for modeling diseases and regenerative medicine. However, to achieve them, the efficient differentiation methods of hiPS cells into aimed cell type in vitro are necessary. Because mesoderm cells are useful in particular, we have developed the differentiation of mouse embryonic stem (mES) cells into mesoderm cells previously. In this time, these methods were improved for hiPS cells and now human mesoderm cells are able to be obtained efficiently. It is certain that the new methods are applicable to various studies and therapies.

  12. Wear Particles Derived from Metal Hip Implants Induce the Generation of Multinucleated Giant Cells in a 3-Dimensional Peripheral Tissue-Equivalent Model

    PubMed Central

    Dutta, Debargh K.; Potnis, Pushya A.; Rhodes, Kelly; Wood, Steven C.

    2015-01-01

    heralds metal on metal hip failures. PMID:25894745

  13. Comparison of trunk and hip muscle activity during different degrees of lumbar and hip extension.

    PubMed

    Kim, Sang-Min; Yoo, Won-Gyu

    2015-09-01

    [Purpose] This study compared the activity of trunk and hip muscles during different degrees of lumbar and hip extension. [Subjects] The study enrolled 18 participants. [Methods] Two exercises (hip and lumbar extension) and two ranges (180° and <180°) were studied. [Results] Differences in degree of extension affected the percentage maximal voluntary isometric contraction of the lumbar erector spinae and biceps femoris muscles, with significantly higher average values at >180° than at 180° lumbar extension. No significant differences were found in gluteus maximus activity according to exercise type or range. [Conclusion] Hip extension may be more effective and safer for lumbar rehabilitation than lumbar extension.

  14. Are Hip Precautions Necessary Post Total Hip Arthroplasty? A Systematic Review

    PubMed Central

    Barnsley, Leslie; Page, Richard

    2015-01-01

    Purpose: Total hip arthroplasty (THA) is a common and effective treatment of hip osteoarthritis. Activity restrictions known as hip precautions are widely practiced in rehabilitation post THA, aiming to foster healing and prevent hip dislocation. The focused clinical question was: Does the application of hip precautions in patients post THA versus unrestricted activities significantly decrease the risk of prosthetic dislocation? Methods: A comprehensive literature search was conducted for randomized controlled trials or cohort studies with a comparative group and minimum 6 months follow-up, with dislocation as an end point. Retrieved titles were assessed independently by 2 reviewers for inclusion and underwent standardized data extraction. Results: Title search produced 80 potentially relevant articles. Five articles were retrieved for data extraction of which 2 met a prior eligibility criteria. No eligible studies were found that concerned posterior approaches to hip arthroplasty, so the results of this review concern only anterolateral approaches. Neither included study showed any benefit of hip precautions in preventing dislocation. Conclusion: The rate of dislocation after anterolateral THA is low and is not improved by hip precautions. Hip precautions are associated with a slower return to activities, significant expense, and decreased patient satisfaction. Existing studies risk being compromised by a type II error, but a definitive study may be prohibitively large and expensive. PMID:26328242

  15. Catastrophic failure of ceramic-on-ceramic total hip arthroplasty presenting as squeaking hip

    PubMed Central

    Malem, David; Nagy, Mathias Thomas; Ghosh, Sabyasachi; Shah, Bhavik

    2013-01-01

    A 68-year-old woman with osteoarthritis had a ceramic-on-ceramic left total hip arthroplasty, including ceramic femoral head and acetabular liner. At 5 years after surgery, the patient developed onset of a very loud squeaking noise, which could be heard 25 m from her, associated with limited hip movement. Findings at revision surgery included a broken ceramic femoral head component, complete wear of the ceramic acetabular component, and black wear debris. Squeaking hip after ceramic-on-ceramic total hip arthroplasty may be associated with catastrophic failure of the arthroplasty components. PMID:23429031

  16. Risks of hip and knee replacement

    MedlinePlus

    ... JW, Crockarell JR. Arthroplasty of the hip In: Canale ST, Beaty JH, eds. Campbell's Operative Orthopaedics . 12th ... 24820247 . Mihalko WM. Arthroplasty of the knee. In: Canale ST, Beaty JH, eds. Campbell's Operative Orthopaedics . 12th ...

  17. Deciding to have knee or hip replacement

    MedlinePlus

    ... JW, Crockarell JR. Arthroplasty of the hip In: Canale ST, Beaty JH, eds. Campbell's Operative Orthopaedics . 12th ... 3. Mihalk WM. Arthroplasty of the knee. In: Canale ST, Beaty JH, eds. Campbell's Operative Orthopaedics . 12th ...

  18. Understanding and Treating the Snapping Hip.

    PubMed

    Yen, Yi-Meng; Lewis, Cara L; Kim, Young-Jo

    2015-12-01

    Snapping hip, or coxa saltans is a palpable or auditory snapping with movement of the hip joint. Extra-articular snapping is divided into external and internal types, and is caused laterally by the iliotibial band and anteriorly by the iliopsoas tendon. Snapping of the iliopsoas usually requires contraction of the hip flexors and may be difficult to distinguish from intra-articular coxa saltans. Ultrasound can be a useful modality to dynamically detect tendon translation during hip movement to support the diagnosis of extra-articular snapping. Coxa saltans is typically treated with conservative measures including anti-inflammatories, stretching, and avoidance of inciting activities. Recalcitrant cases are treated with surgery to lengthen the iliopsoas or the iliotibial band. PMID:26524554

  19. Microbial assisted High Impact Polystyrene (HIPS) degradation.

    PubMed

    Mohan, Arya J; Sekhar, Vini C; Bhaskar, Thallada; Nampoothiri, K Madhavan

    2016-08-01

    The efficacy of newly isolated Pseudomonas and Bacillus strains to degrade brominated High Impact Polystyrene (HIPS) was investigated. Viability of these cultures while using e-plastic as sole carbon source was validated through Triphenyl Tetrazolium Chloride (TTC). Four days incubation of HIPS emulsion with Bacillus spp. showed 94% reduction in turbidity and was 97% with Pseudomonas spp. Confirmation of degradation was concluded by HPLC, NMR, FTIR, TGA and weight loss analysis. NMR spectra of the degraded film revealed the formation of aliphatic carbon chain with bromine and its release. FTIR analysis of the samples showed a reduction in CH, CO and CN groups. Surface changes in the brominated HIPS film was visualized through SEM analysis. Degradation with Bacillus spp showed a weight loss of 23% (w/w) of HIPS film in 30days.

  20. Hip fracture as the tracer condition.

    PubMed

    Kassim Javaid, M; Chana, Jasroop; Cooper, Cyrus

    2013-12-01

    Hip fractures represent the most severe complication of osteoporosis from the perspectives of the patient, carer, health care system and society. Given the strong association with age, numbers are set to rise significantly in the next few decades despite evidence that the age adjusted rates in some countries are either plateauing or falling. Given the almost invariable need for inpatient admission, hospital administrative data for hip fractures remain a robust measure of number of hip fractures in the community and can be extrapolated to determine the total expected number of clinical fragility fractures from the same population. Both process and outcome standards have now been developed to benchmark clinical quality in the care of patients with hip fractures and fragility fractures at other sites. PMID:24836330

  1. Taking care of your new hip joint

    MedlinePlus

    ... Cabrera AL. Total hip replacement. In: Frontera, WR, Silver JK, Rizzo TD, eds. Essentials of Physical Medicine ... Groomes TE. Total knee replacement. In: Frontera, WR, Silver JK, Rizzo TD, eds. Essentials of Physical Medicine ...

  2. Hip and groin injuries in athletes.

    PubMed

    Anderson, K; Strickland, S M; Warren, R

    2001-01-01

    Although athletic injuries about the hip and groin occur less commonly than injuries in the extremities, they can result in extensive rehabilitation time. Thus, an accurate diagnosis and well-organized treatment plan are critical. Because loads of up to eight times body weight have been demonstrated in the hip joint during jogging, presumably even greater loads can occur during vigorous athletic competition. The available imaging modalities are effective diagnostic tools when selected on the basis of a thorough history and physical examination. Considerable controversy exists as to the cause and optimal treatment of groin pain in athletes, or the so-called "sports hernia." There has also been significant recent attention focused on intraarticular lesions that may be amenable to hip arthroscopy. This article briefly reviews several common hip and groin conditions affecting athletic patients and highlights some newer topics. PMID:11476397

  3. Apparent spontaneous joint restoration in hip osteoarthritis.

    PubMed

    Guyton, Gregory P; Brand, Richard A

    2002-11-01

    Dramatic spontaneous restoration of the joint space in osteoarthritis of the hip is rare, although limited fibrocartilaginous repair is common. Regeneration of the apparent radiographic joint space seems to be associated with peripheral osteophyte formation, but it is difficult to isolate other well-defined factors that promote it. Previous documentation of the phenomenon exists in scattered case reports before the era of widespread total hip replacement. Two recent cases are presented in which patients with bilateral disease had unilateral total hip replacement with simultaneous diminished pain in the contralateral hip accompanied by restoration of the radiographic joint space. Secondary stability, unloading, peripheral osteophyte formation, and other possible factors likely contribute to these unusual natural outcomes of coxarthrosis.

  4. American Association of Hip and Knee Surgeons

    MedlinePlus

    ... Replacement Surgery Will my artificial joint set off airport security metal detectors? Preventing Infection in Your Joint at ... Knee Replacement Will my artificial joint set off airport security metal detectors? Contact Us Draft Hip Arthroplasty Performance ...

  5. Wear of 36-mm BIOLOX(R) delta ceramic-on-ceramic bearing in total hip replacements under edge loading conditions.

    PubMed

    Al-Hajjar, Mazen; Fisher, John; Tipper, Joanne L; Williams, Sophie; Jennings, Louise M

    2013-05-01

    Ceramic-on-ceramic bearings have become of great interest due to the substantial improvements in the manufacturing techniques and material properties and due to polyethylene wear debris-induced osteolysis and the issues with metal wear debris and ion release by metal-on-metal bearings. Edge loading conditions due to translational malpositioning (microseparation conditions) have been shown to replicate clinically relevant wear mechanisms and increase the wear of ceramic-on-ceramic bearings; thus, it was necessary to test new bearing materials and designs under these adverse conditions. The aim of this study was to assess the effect of increasing head size on the wear of BIOLOX(®) delta ceramic-on-ceramic bearings under edge loading conditions due to rotational (steep cup inclination angle) and translational (microseparation) malpositioning. In this study, six 36-mm ceramic-on-ceramic bearings (BIOLOX delta, CeramTec, Germany) were tested under standard and edge loading conditions using the Leeds II hip simulator and compared to the 28-mm bearings tested and published previously under identical conditions. The mean wear rate under standard gait conditions was below 0.1 mm(3)/million cycles for both the 28-mm and the 36-mm ceramic-on-ceramic bearings, and increasing the inclination angle did not affect the wear rates. The introduction of microseparation to the gait cycle increased the wear rate of ceramic-on-ceramic bearing and resulted in stripe wear on the femoral heads. Under microseparation conditions, the wear rate of size 36-mm bearings (0.22 mm(3)/million cycles) was significantly higher (p = 0.004) than that for size 28-mm bearings (0.13 mm(3)/million cycles). This was due to the larger contact area for the larger bearings and deprived lubrication under edge loading conditions. The wear rate of BIOLOX delta ceramic-on-ceramic bearings under microseparation conditions was still very low (<0.25 mm(3)/million cycles) compared to earlier generation

  6. Arthroscopic Hip Revision Surgery for Residual FAI

    PubMed Central

    Larson, Christopher M.; Giveans, Russell; Bedi, Asheesh; Samuelson, Kathryn M.; Stone, Rebecca M.

    2014-01-01

    Objectives: There is a steep surgical learning curve when managing femoroacetabular impingement (FAI) and residual FAI can lead to continued pain and disability. There is very limited data reporting outcomes after revision arthroscopy for residual FAI. Methods: The records of patients that underwent arthroscopic hip revision surgery for residual FAI based on plain radiographs and 3D CT scans were reviewed. Pre and post-operative structural pathomorphology, intra-operative findings, and pre and post-operative outcomes measures using Modified Harris Hip Scoring (MHHS), SF-12 scoring, and pain on a visual analogue scale (VAS) were evaluated. Outcomes after revision arthroscopic FAI correction were compared to a cohort that underwent primary arthroscopic FAI correction. Results: 59 patients (85 hips) underwent arthroscopic revision FAI correction (mean 20.8 months follow-up). There were 98 previous arthroscopic surgeries and 4 previous surgical dislocations. There were 39 males and 46 females with a mean age of 29.5 years (range 16 - 59). 80 hips had residual cam-type FAI, and 64 hips had residual pincer-type FAI and underwent femoral and rim resections, respectively. The labrum was debrided in 27 hips, repaired in 48 hips and reconstructed with allograft in 8 hips. Adhesions were excised for 54 hips. The results of revision arthroscopic FAI correction were compared to 154 patients (169 hips) that underwent primary arthroscopic FAI correction (mean 25.2 months follow-up). The mean improvement for outcomes scores after revision FAI correction was 18.9 points (MHHS, p<.01), 13.4 points (SF-12, p<.01), and 2.2 points (VAS, p<.01) compared to 23.7 points (MHHS, p<.01), 22.3 points (SF-12, p<.01), and 4.6 points (VAS, p<.01) after primary arthroscopic FAI correction. Most recent outcomes scores and mean improvement in outcome scores were significantly better after primary (81.1% good/ excellent results) compared to revision (69.8% good/excellent results) FAI correction (MHS

  7. An overview of hip injuries in running.

    PubMed

    Paluska, Scott A

    2005-01-01

    Running has steadily gained in worldwide popularity and is the primary exercise modality for many individuals of all ages. Its low cost, versatility, convenience and related health benefits appeal to men and women of broad cultural, ethnic and economic backgrounds. With more children and adults participating in recreational and competitive running, the incidence of injuries has steadily increased. Most running-related injuries affecting the lower extremities are due to preventable training errors, and some may necessitate medical evaluation or a significant reduction in training. Hip injuries in runners are due to interactions of intrinsic and extrinsic factors that adversely affect the complex regional anatomy. Acute or chronic hip pain presents a diagnostic and therapeutic challenge because the vague, nonspecific symptoms and signs may originate from local, regional or distant foci. Muscle strains and tendonitis are the most common aetiologies of hip pain and typically result from sudden acceleration/deceleration manoeuvres, direction changes or eccentric contractions. Apophysitis and avulsion fractures may affect younger runners and produce localised pain at muscle attachment sites. Iliotibial band syndrome is a common cause of lateral hip and knee symptoms characterised by sharp or burning pain that is exacerbated by activity. Bursitis, due to repetitive activity or acute trauma, may affect the trochanteric, ischial or iliopectineal bursae. Hip osteoarthritis may also produce persistent pain that worsens with running. Stress fractures are potentially serious conditions that affect women more frequently than men. Snapping hip syndrome is a benign condition that results from tight connective tissues' passing repeatedly over the greater trochanter, anterior hip capsule, lesser trochanter, femoral head or iliopectineal eminence. Acetabular labral tears, sports hernias and nerve entrapment syndromes are also potential causes of persistent hip pain in runners

  8. NEW BEARING SURFACES IN TOTAL HIP REPLACEMENT

    PubMed Central

    Schwartsmann, Carlos Roberto; Boschin, Leonardo Carbonera; Gonçalves, Ramiro Zilles; Yépez, Anthony Kerbes; de Freitas Spinelli, Leandro

    2015-01-01

    Total hip arthroplasty is being increasingly indicated for younger and more active patients, in addition to a naturally growing demand for the procedure because of increasing life expectancy among patients. The high costs of this surgery and the controversies regarding implant performance have made this topic the subject of constant research, seeking new materials with better resistance to wear and better biocompatibility. The present article provides a review of new surfaces in total hip arthroplasty. PMID:27042614

  9. Celiac Disease in Women with Hip Fractures

    PubMed Central

    LeBoff, Meryl S.; Cobb, Haley; Gao, Lisa Y.; Hawkes, William; Yu-Yahiro, Janet; Kolatkar, Nikheel S.; Magaziner, Jay

    2014-01-01

    Objective Celiac disease is associated with decreased bone density, however, the risk of fractures in celiac disease patients is unclear. We compared the prevalence of celiac disease between a group of women with hip fractures and a group of women undergoing elective joint replacement surgery and the association between celiac disease and vitamin D levels. Methods Two hundred eight community dwelling and postmenopausal women were recruited from Boston, MA (n=81) and Baltimore, MD (n=127). We measured tissue transglutaminase IgA by ELISA to diagnose celiac disease and 25-hydroxyvitamin D (25(OH)D) levels by radioimmunoassay in both women with hip fractures (n=157) and the control group (n=51), all of whom were from Boston. Subjects were excluded if they took any medications or had medical conditions that might affect bone. Results Median serum 25(OH)D levels were significantly lower (p< 0.0001) in the hip fracture cohorts compared to the elective joint replacement cohort (14.1 ng/ml vs. 21.3 ng/ml, respectively). There were no differences in the percentage of subjects with a positive tissue transglutaminase in the women with hip fractures versus the control group (1.91% vs. 1.61%, respectively). Conclusion Vitamin D levels are markedly reduced in women with hip fractures, however hip fracture patients did not show a higher percentage of positive tissue transglutaminase levels compared with controls. These data suggest that routine testing for celiac disease among hip fracture patients may not prove useful, although larger prospective studies among hip fracture subjects are needed. PMID:23732553

  10. Snapping hip: etiopathogenesis and surgical treatment.

    PubMed

    Noia, F; Miceli, D; Rotini, R; Fontanesi, G

    1999-01-01

    Snapping hip is a polymorphous pathology the genesis of which is multifactorial, characterized by a snapping sensation which may be painful, and occurring during movement of the hip or during walking. Clinical and instrumental diagnosis for an accurate etiopathogenetic classification is essential to correct surgical treatment, that must be reserved only for cases with painful symptoms and with disorders in walking. The authors provide a classification system of the syndrome, describing four different varieties of the pathology and relative surgical treatment.

  11. [Treatment of hip fractures in elderly patients].

    PubMed

    Hack, Juliana; Bliemel, Christopher; Ruchholtz, Steffen; Bücking, Benjamin

    2015-04-01

    Hip fractures are among the most common fractures in elderly people. The annual number of femoral fractures is even expected to increase because of an aging society. Due to the high number of comorbidities, there are special challenges in treating geriatric hip fracture patients, which require a multidisciplinary management. This includes surgical treatment allowing full weight bearing in the immediate postoperative period, osteoporosis treatment and falls prevention as well as an early ortho-geriatric rehabilitation program.

  12. Hip adductors' strength, flexibility, and injury risk.

    PubMed

    Hrysomallis, Con

    2009-08-01

    The hip adductor muscle group plays an important role in both movement and stability at the hip joint in many athletic pursuits. Injury to this muscle group has been reported in a number of sports, among them, ice hockey, soccer, Australian football, and swimming. The identification of muscle characteristics that predispose a muscle to injury is an important step in developing conditioning programs to reduce injury risk. Muscle strength and range of motion are 2 parameters that may influence injury risk. The aim of this review was to examine the relationship between hip adductors' strength, flexibility, and injury risk. Strength testing has involved isokinetic or hand-held dynamometry. Flexibility has usually been assessed by goniometry during maximal hip abduction. An association has been reported between adductor strength deficits and injury for ice hockey players. Low adductor flexibility has also been identified as a risk factor for injury in soccer players. An intervention program that strengthened the hip adductors had some success in reducing injury risk for ice hockey players. There is some low- to moderate-level evidence from cohort studies to suggest that flexibility and strength are related to injury risk in particular sports and that an intervention program may be effective in reducing injury risk. Higher level evidence from randomized controlled trials is required to firmly establish the link between hip adductor flexibility, strength, and injury. PMID:19620912

  13. Quality of life impairments after hip arthroscopy in people with hip chondropathy

    PubMed Central

    Filbay, Stephanie R.; Kemp, Joanne L.; Ackerman, Ilana N.; Crossley, Kay M.

    2016-01-01

    Many young individuals undergoing hip arthroscopic surgery have hip chondropathy. The impact of mild or more severe hip chondropathy 1–2 years following arthroscopy is poorly understood. The purpose of this study was to (i) compare health-related quality of life (HRQoL), anxiety and depression scores between people who underwent arthroscopic treatment for hip chondropathy 1–2 years previously and pain-free controls; (ii) compare HRQoL, hip-related quality of life (QoL) and anxiety/depression scores in people with mild versus severe hip chondropathy and (iii) compare hip-related QoL items between chondropathy groups. The Hip disability and Osteoarthritis Outcome Score (HOOS), International Hip Outcome Tool (iHOT-33), EuroQol-5D and Hospital Anxiety and Depression Scale (HADS) were compared between 71 individuals aged 18–60 years following arthroscopic treatment for hip chondroplasty (12–24 months previously) and 46 healthy controls. Comparisons were also performed between people with mild (Outerbridge grade 1–2) and severe (Outerbridge grade 3–4) hip chondropathy. Participants following arthroscopic treatment for hip chondroplasty reported worse HRQoL, hip-related QoL and anxiety, compared with pain-free controls (all P < 0.05), but no difference in self-care (P = 0.20). There were differences between mild and severe chondropathy groups for pain during sport/recreation [median (IQR) 20 (5–80) versus 60 (25–90) P = 0.01), pain after activity (40 (20–75) versus 75 (50–90) P = 0.01), difficulty maintaining fitness (30 (10–70) versus 75 (35–85) P = 0.02) and reduced hip confidence. Hip chondropathy was associated with significant QoL impairment, with severe chondropathy associated with the greatest impairment. The identification of specific areas of QoL impairment provides avenues to target rehabilitation and support. PMID:27583152

  14. Quality of life impairments after hip arthroscopy in people with hip chondropathy.

    PubMed

    Filbay, Stephanie R; Kemp, Joanne L; Ackerman, Ilana N; Crossley, Kay M

    2016-07-01

    Many young individuals undergoing hip arthroscopic surgery have hip chondropathy. The impact of mild or more severe hip chondropathy 1-2 years following arthroscopy is poorly understood. The purpose of this study was to (i) compare health-related quality of life (HRQoL), anxiety and depression scores between people who underwent arthroscopic treatment for hip chondropathy 1-2 years previously and pain-free controls; (ii) compare HRQoL, hip-related quality of life (QoL) and anxiety/depression scores in people with mild versus severe hip chondropathy and (iii) compare hip-related QoL items between chondropathy groups. The Hip disability and Osteoarthritis Outcome Score (HOOS), International Hip Outcome Tool (iHOT-33), EuroQol-5D and Hospital Anxiety and Depression Scale (HADS) were compared between 71 individuals aged 18-60 years following arthroscopic treatment for hip chondroplasty (12-24 months previously) and 46 healthy controls. Comparisons were also performed between people with mild (Outerbridge grade 1-2) and severe (Outerbridge grade 3-4) hip chondropathy. Participants following arthroscopic treatment for hip chondroplasty reported worse HRQoL, hip-related QoL and anxiety, compared with pain-free controls (all P < 0.05), but no difference in self-care (P = 0.20). There were differences between mild and severe chondropathy groups for pain during sport/recreation [median (IQR) 20 (5-80) versus 60 (25-90) P = 0.01), pain after activity (40 (20-75) versus 75 (50-90) P = 0.01), difficulty maintaining fitness (30 (10-70) versus 75 (35-85) P = 0.02) and reduced hip confidence. Hip chondropathy was associated with significant QoL impairment, with severe chondropathy associated with the greatest impairment. The identification of specific areas of QoL impairment provides avenues to target rehabilitation and support. PMID:27583152

  15. Comparative Effectiveness of Ceramic-on-Ceramic Implants in Stemmed Hip Replacement

    PubMed Central

    Sedrakyan, Art; Graves, Stephen; Bordini, Barbara; Pons, Miquel; Havelin, Leif; Mehle, Susan; Paxton, Elizabeth; Barber, Thomas; Cafri, Guy

    2014-01-01

    Background: The rapid decline in use of conventional total hip replacement with a large femoral head size and a metal-on-metal bearing surface might lead to increased popularity of ceramic-on-ceramic bearings as another hard-on-hard alternative that allows implantation of a larger head. We sought to address comparative effectiveness of ceramic-on-ceramic and metal-on-HXLPE (highly cross-linked polyethylene) implants by utilizing the distributed health data network of the ICOR (International Consortium of Orthopaedic Registries), an unprecedented collaboration of national and regional registries and the U.S. FDA (Food and Drug Administration). Methods: A distributed health data network was developed by the ICOR and used in this study. The data from each registry are standardized and provided at a level of aggregation most suitable for the detailed analysis of interest. The data are combined across registries for comprehensive assessments. The ICOR coordinating center and study steering committee defined the inclusion criteria for this study as total hip arthroplasty performed without cement from 2001 to 2010 in patients forty-five to sixty-four years of age with osteoarthritis. Six national and regional registries (Kaiser Permanente and HealthEast in the U.S., Emilia-Romagna region in Italy, Catalan region in Spain, Norway, and Australia) participated in this study. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. We present the results of the fixed-effects model and include the results of the random-effects model in an appendix. SAS version 9.2 was used for all analyses. We first compared femoral head sizes of >28 mm and ≤28 mm within ceramic-on-ceramic implants and then compared ceramic-on-ceramic with metal-on-HXLPE. Results: A total of 34,985 patients were included; 52% were female. We found a lower risk of revision associated with use of ceramic-on-ceramic implants when a larger head

  16. Safe and effective one-session fractional skin resurfacing using a carbon dioxide laser device in super-pulse mode: a clinical and histologic study.

    PubMed

    Trelles, Mario A; Shohat, Michael; Urdiales, Fernando

    2011-02-01

    Carbon dioxide (CO(2)) laser ablative fractional resurfacing produces skin damage, with removal of the epidermis and variable portions of the dermis as well as associated residual heating, resulting in new collagen formation and skin tightening. The nonresurfaced epidermis helps tissue to heal rapidly, with short-term postoperative erythema. The results for 40 patients (8 men and 32 women) after a single session of a fractional CO(2) resurfacing mode were studied. The treatments included resurfacing of the full face, periocular upper lip, and residual acne scars. The patients had skin prototypes 2 to 4 and wrinkle degrees 1 to 3. The histologic effects, efficacy, and treatment safety in various clinical conditions and for different phototypes are discussed. The CO(2) laser for fractional treatment is used in super-pulse mode. The beam is split by a lens into several microbeams, and super-pulse repetition is limited by the pulse width. The laser needs a power adaptation to meet the set fluence per microbeam. Laser pulsing can operate repeatedly on the same spot or be moved randomly over the skin, using several passes to achieve a desired residual thermal effect. Low, medium, and high settings are preprogrammed in the device, and they indicate the strength of resurfacing. A single treatment was given with the patient under topical anesthesia. However, the anesthesia was injected on areas of scar tissue. Medium settings (2 Hz, 30 W, 60 mJ) were used, and two passes were made for dark skins and degree 1 wrinkles. High settings (2 Hz, 60 W, 120 mJ) were used, and three passes were made for degree 3 wrinkles and scar tissue. Postoperatively, resurfaced areas were treated with an ointment of gentamycin, Retinol Palmitate, and DL-methionine (Novartis; Farmaceutics, S.A., Barcelona, Spain). Once epithelialization was achieved, antipigment and sun protection agents were recommended. Evaluations were performed 15 days and 2 months after treatment by both patients and

  17. Pressure sores and hip fractures.

    PubMed

    Haleem, S; Heinert, G; Parker, M J

    2008-02-01

    Development of pressure sores during hospital admission causes morbidity and distress to the patient, increases strain on nursing resources, delaying discharge and possibly increasing mortality. A hip fracture in elderly patients is a known high-risk factor for development of pressure sores. We aimed to determine the current incidence of pressure sores and identify those factors which were associated with an increased risk of pressure sores. We retrospectively analysed prospectively collected data of 4654 consecutive patients admitted to a single unit. One hundred and seventy-eight (3.8%) of our patients developed pressure sores. Patient factors that increased the risk of pressure sores were increased age, diabetes mellitus, a lower mental test score, a lower mobility score, a higher ASA score, lower admission haemoglobin and an intra-operative drop in blood pressure. The risk was higher in patients with an extracapsular neck of femur fracture and patients with an increased time interval between admission to hospital and surgery. Our studies indicate that while co-morbidities constitute a substantial risk in an elderly population, the increase in incidence of pressure sores can be reduced by minimising delays to surgery. PMID:18234201

  18. [Candida infection in hip alloarthroplasty].

    PubMed

    Prenzel, K L; Isenberg, J; Helling, H J; Rehm, K E

    2003-01-01

    A 46-year-old polytoxicomanic patient underwent a total hip replacement for necrosis of the femoral head. The patient suffered additionally from chronic pancreatitis with insulin-dependent diabetes and polyneuropathy. Three weeks later he developed a deep wound infection followed by surgical revision. The infection persisted despite further revision operations and systemically and locally applied antibiotics. After removal of the prosthesis,microbiology revealed Staphylococcus aureus, enterococcus,and Candida parapsilosis. Five additional revision operations, application of suction-irrigation drainage, and systemically administered antibiotics could not stop the infectious process. The patient was transferred to our institution 3 months after primary surgery. The joint defect was filled with a PMMA Palacos spacer. This time biopsies were only positive for Candida albicans. After 12 days of antifungal therapy with fluconazole,microbiological biopsies were sterile. The spacer was removed and femoral extension applied. After 4 weeks of further antifungal therapy, a revision prosthesis was implanted. Until now no signs of infection have appeared.

  19. Efficacy of Punch Elevation Combined with Fractional Carbon Dioxide Laser Resurfacing in Facial Atrophic Acne Scarring: A Randomized Split-face Clinical Study

    PubMed Central

    Faghihi, Gita; Nouraei, Saeid; Asilian, Ali; Keyvan, Shima; Abtahi-Naeini, Bahareh; Rakhshanpour, Mehrdad; Nilforoushzadeh, Mohammad Ali; Hosseini, Sayed Mohsen

    2015-01-01

    Background: A number of treatments for reducing the appearance of acne scars are available, but general guidelines for optimizing acne scar treatment do not exist. The aim of this study was to compare the clinical effectiveness and side effects of fractional carbon dioxide (CO2) laser resurfacing combined with punch elevation with fractional CO2 laser resurfacing alone in the treatment of atrophic acne scars. Materials and Methods: Forty-two Iranian subjects (age range 18–55) with Fitzpatrick skin types III to IV and moderate to severe atrophic acne scars on both cheeks received randomized split-face treatments: One side received fractional CO2 laser treatment and the other received one session of punch elevation combined with two sessions of laser fractional CO2 laser treatment, separated by an interval of 1 month. Two dermatologists independently evaluated improvement in acne scars 4 and 16 weeks after the last treatment. Side effects were also recorded after each treatment. Results: The mean ± SD age of patients was 23.4 ± 2.6 years. Clinical improvement of facial acne scarring was assessed by two dermatologists blinded to treatment conditions. No significant difference in evaluation was observed 1 month after treatment (P = 0.56). Their evaluation found that fractional CO2 laser treatment combined with punch elevation had greater efficacy than that with fractional CO2 laser treatment alone, assessed 4 months after treatment (P = 0.02). Among all side effects, coagulated crust formation and pruritus at day 3 after fractional CO2 laser treatment was significant on both treatment sides (P < 0.05). Conclusion: Concurrent use of fractional laser skin resurfacing with punch elevation offers a safe and effective approach for the treatment of acne scarring. PMID:26538695

  20. Results of fractional ablative facial skin resurfacing with the erbium:yttrium-aluminium-garnet laser 1 week and 2 months after one single treatment in 30 patients.

    PubMed

    Trelles, Mario A; Mordon, Serge; Velez, Mariano; Urdiales, Fernando; Levy, Jean Luc

    2009-03-01

    The erbium:yttrium-aluminium-garnet (Er:YAG) laser has recently been used in the fractional resurfacing of photo-aged skin. Our study evaluated the results after one single session of fractional resurfacing with Er:YAG. Thirty women participated in the study, with an average age of 46 years, skin types from II to IV, and wrinkle grades I to III. The 2,940 nm Er:YAG system used (Pixel, Alma Laser, Israel) had variable pulse durations (1 ms to 2 ms) and energy densities (800 mJ/cm(2) to 1,400 mJ/cm(2)) which, together with the number of passes (four to eight), were selected as a function of wrinkle severity. All patients received only one treatment. Postoperative side effects were evaluated. The number of wrinkles was documented with clinical photography and was scored. Histological assessment was carried out on two patients before and 2 months after treatment. All patients completed the study. Of the patients, 93% reported good or very good improvement of the degree of their wrinkles, with a satisfaction index of 83%. Pain was not a problem during treatment, and there were no side effects except for in one phototype IV patient, who had hyperpigmentation. Histology 2 months after the single treatment demonstrated younger morphology of both the epidermis and dermis, with improvement of the pretreatment typical elastotic appearance. At the parameters used in our study, only one treatment session of Er:YAG laser could achieve effective skin rejuvenation, with effects recognized in both the dermis and, more importantly, the epidermis. This regimen offers an interesting alternative to the conventional approach of multi-session fractional resurfacing.

  1. Ablative non-fractional lasers for atrophic facial acne scars: a new modality of erbium:YAG laser resurfacing in Asians.

    PubMed

    Lee, Sang Ju; Kang, Jin Moon; Chung, Won Soon; Kim, Young Koo; Kim, Hei Sung

    2014-03-01

    Atrophic facial scars which commonly occur after inflammatory acne vulgaris can be extremely disturbing to patients both physically and psychologically. Treatment with fractional laser devices has become increasingly popular, but there has been disappointment in terms of effectiveness. The objective of this study was to assess the safety and efficacy of ablative full-face resurfacing on atrophic acne scars in the Korean population. A total of 22 patients, aged 25-44 years, underwent a new modality of resurfacing combining both short-pulsed and dual-mode erbium:yttrium-aluminum garnet (Er:YAG) laser. The patients had Fitzpatrick skin types ranging from III to V. Photographs were taken before and up to 6 months after treatment. Results were evaluated for the degree of clinical improvement and any adverse events. Degree of improvement was graded using a four-point scale: poor (1) = <25%, fair (2) = 25-50%, good (3) = 51-75%, and excellent (4) = >75%. Based on the blinded photo assessments by two independent reviewers, clinically and statistically significant mean improvement of 3.41 was observed (one-sample Wilcoxon signed rank test, P < 0.001). Complete wound healing occurred between 6 and 9 days. Erythema occurred in all patients and lasted longer than 3 months in two patients (9.1%). Postinflammatory hyperpigmentation occurred in ten patients (45.5%) and lasted longer than 3 months in one patient (4.5%). One patient experienced mild hypopigmentation (4.5%). Mild to moderate acne flare-up occurred in five patients (22.7%). No other adverse effects were observed. A new modality of Er:YAG laser resurfacing combining short-pulsed and dual-mode Er:YAG laser is a safe and very effective treatment modality for atrophic facial acne scars in Asians with darker skin tones.

  2. Hip reconstruction osteotomy by Ilizarov method as a salvage option for abnormal hip joints.

    PubMed

    Umer, Masood; Rashid, Haroon; Umer, Hafiz Muhammad; Raza, Hasnain

    2014-01-01

    Hip joint instability can be secondary to congenital hip pathologies like developmental dysplasia (DDH) or acquired such as sequel of infective or neoplastic process. An unstable hip is usually associated with loss of bone from the proximal femur, proximal migration of the femur, lower-extremity length discrepancy, abnormal gait, and pain. In this case series of 37 patients coming to our institution between May 2005 and December 2011, we report our results in treatment of unstable hip joint by hip reconstruction osteotomy using the Ilizarov method and apparatus. This includes an acute valgus and extension osteotomy of the proximal femur combined with gradual varus and distraction (if required) for realignment and lengthening at a second, more distal, femoral osteotomy. 18 males and 19 females participated in the study. There were 17 patients with DDH, 12 with sequelae of septic arthritis, 2 with tuberculous arthritis, 4 with posttraumatic arthritis, and 2 with focal proximal femoral deficiency. Outcomes were evaluated by using Harris Hip Scoring system. At the mean follow-up of 37 months, Harris Hip Score had significantly improved in all patients. To conclude, illizarov hip reconstruction can successfully improve Trendelenburg's gait. It supports the pelvis and simultaneously restores knee alignment and corrects lower-extremity length discrepancy (LLD). PMID:24895616

  3. Hip reconstruction osteotomy by Ilizarov method as a salvage option for abnormal hip joints.

    PubMed

    Umer, Masood; Rashid, Haroon; Umer, Hafiz Muhammad; Raza, Hasnain

    2014-01-01

    Hip joint instability can be secondary to congenital hip pathologies like developmental dysplasia (DDH) or acquired such as sequel of infective or neoplastic process. An unstable hip is usually associated with loss of bone from the proximal femur, proximal migration of the femur, lower-extremity length discrepancy, abnormal gait, and pain. In this case series of 37 patients coming to our institution between May 2005 and December 2011, we report our results in treatment of unstable hip joint by hip reconstruction osteotomy using the Ilizarov method and apparatus. This includes an acute valgus and extension osteotomy of the proximal femur combined with gradual varus and distraction (if required) for realignment and lengthening at a second, more distal, femoral osteotomy. 18 males and 19 females participated in the study. There were 17 patients with DDH, 12 with sequelae of septic arthritis, 2 with tuberculous arthritis, 4 with posttraumatic arthritis, and 2 with focal proximal femoral deficiency. Outcomes were evaluated by using Harris Hip Scoring system. At the mean follow-up of 37 months, Harris Hip Score had significantly improved in all patients. To conclude, illizarov hip reconstruction can successfully improve Trendelenburg's gait. It supports the pelvis and simultaneously restores knee alignment and corrects lower-extremity length discrepancy (LLD).

  4. Invariant hip moment pattern while walking with a robotic hip exoskeleton.

    PubMed

    Lewis, Cara L; Ferris, Daniel P

    2011-03-15

    Robotic lower limb exoskeletons hold significant potential for gait assistance and rehabilitation; however, we have a limited understanding of how people adapt to walking with robotic devices. The purpose of this study was to test the hypothesis that people reduce net muscle moments about their joints when robotic assistance is provided. This reduction in muscle moment results in a total joint moment (muscle plus exoskeleton) that is the same as the moment without the robotic assistance despite potential differences in joint angles. To test this hypothesis, eight healthy subjects trained with the robotic hip exoskeleton while walking on a force-measuring treadmill. The exoskeleton provided hip flexion assistance from approximately 33% to 53% of the gait cycle. We calculated the root mean squared difference (RMSD) between the average of data from the last 15 min of the powered condition and the unpowered condition. After completing three 30-min training sessions, the hip exoskeleton provided 27% of the total peak hip flexion moment during gait. Despite this substantial contribution from the exoskeleton, subjects walked with a total hip moment pattern (muscle plus exoskeleton) that was almost identical and more similar to the unpowered condition than the hip angle pattern (hip moment RMSD 0.027, angle RMSD 0.134, p<0.001). The angle and moment RMSD were not different for the knee and ankle joints. These findings support the concept that people adopt walking patterns with similar joint moment patterns despite differences in hip joint angles for a given walking speed. PMID:21333995

  5. HIP HOP for HIV Awareness: Using Hip Hop Culture to Promote Community-Level HIV Prevention

    ERIC Educational Resources Information Center

    Hill, Mandy J.; Hallmark, Camden J.; McNeese, Marlene; Blue, Nike; Ross, Michael W.

    2014-01-01

    The goal of this paper was to determine the effectiveness of the HIP HOP for HIV Awareness intervention, an innovative model utilising an exchange of an HIV test for a hip hop concert ticket, in a metropolitan city among African American youth and young adults. A subset of intervention participants participated in standardised testing, sex…

  6. The 1963 Hip-Hop Machine: Hip-Hop Pedagogy as Composition.

    ERIC Educational Resources Information Center

    Rice, Jeff

    2003-01-01

    Proposes an alternative invention strategy for research-based argumentative writing. Investigates the coincidental usage of the term "whatever" in hip-hop, theory, and composition studies. Presents a "whatever-pedagogy" identified as "hip-hop pedagogy," a writing practice that models itself after digital sampling's rhetorical strategy of…

  7. Powered hip exoskeletons can reduce the user's hip and ankle muscle activations during walking.

    PubMed

    Lenzi, Tommaso; Carrozza, Maria Chiara; Agrawal, Sunil K

    2013-11-01

    In this paper, we study the human locomotor adaptation to the action of a powered exoskeleton providing assistive torque at the user's hip during walking. To this end, we propose a controller that provides the user's hip with a fraction of the nominal torque profile, adapted to the specific gait features of the user from Winter's reference data . The assistive controller has been implemented on the ALEX II exoskeleton and tested on ten healthy subjects. Experimental results show that when assisted by the exoskeleton, users can reduce the muscle effort compared to free walking. Despite providing assistance only to the hip joint, both hip and ankle muscles significantly reduced their activation, indicating a clear tradeoff between hip and ankle strategy to propel walking. PMID:23529105

  8. Arthroscopic intervention in early hip disease.

    PubMed

    McCarthy, Joseph C; Lee, Jo-Ann

    2004-12-01

    Advancement in diagnostic and therapeutic applications for hip arthroscopy have dispelled previous myths about early hip disease. Arthroscopic findings have established the following facts: Acetabular labral tears do occur; acetabular chondral lesions do exist; tears are most frequently anterior and often associated with sudden twisting or pivoting motions; and labral tears often occur in association with articular cartilage lesions of the adjacent acetabulum or femoral head, and if present for years, contribute to the progression of delamination process of the chondral cartilage. Magnetic resonance arthrography represents an improvement over conventional magnetic resonance imaging, it does have limitations when compared with direct observation. Although indications for hip arthroscopy are constantly expanding, the most common indications include: labral tears, loose bodies, chondral flap lesions of the acetabular or femoral head, synovial chondromatosis, foreign body removal, and crystalline hip arthropathy (gout, pseudogout, and others). Contraindications include conditions that limit the potential for hip distraction such as joint ankylosis, dense heterotopic bone formation, considerable protrusio, or morbid obesity. Complication rates have been reported between 0.5 and 5%, most often related to distraction and include sciatic or femoral nerve palsy, avascular necrosis, and compartment syndrome. Transient peroneal or pudendal nerve effects and chondral scuffing have been associated with difficult or prolonged distraction. Meticulous consideration to patient positioning, distraction time and portal placement are essential. Judicious patient selection and diagnostic expertise are critical to successful outcomes. Candidates for hip arthroscopy should include only those patients with mechanical symptoms (catching, locking, or buckling) that have failed to respond to conservative therapy. The extent of articular cartilage involvement has the most direct relationship

  9. The World Hip Trauma Evaluation Study 3

    PubMed Central

    Parsons, N.; Achten, J.; Griffin, X. L.; Costa, M. L.; Reed, M. R.

    2016-01-01

    Background Approximately half of all hip fractures are displaced intracapsular fractures. The standard treatment for these fractures is either hemiarthroplasty or total hip arthroplasty. The recent National Institute for Health and Care Excellence (NICE) guidance on hip fracture management recommends the use of ‘proven’ cemented stem arthroplasty with an Orthopaedic Device Evaluation Panel (ODEP) rating of at least 3B (97% survival at three years). The Thompsons prosthesis is currently lacking an ODEP rating despite over 50 years of clinical use, likely due to the paucity of implant survival data. Nationally, adherence to these guidelines is varied as there is debate as to which prosthesis optimises patient outcomes. Design This study design is a multi-centre, multi-surgeon, parallel, two arm, standard-of-care pragmatic randomised controlled trial. It will be embedded within the WHiTE Comprehensive Cohort Study (ISRCTN63982700). The main analysis is a two-way equivalence comparison between Hemi-Thompson and Hemi-Exeter polished taper with Unitrax head. Secondary outcomes will include radiological leg length discrepancy measured as per Bidwai and Willett, mortality, re-operation rate and indication for re-operation, length of index hospital stay and revision at four months. This study will be supplemented by the NHFD (National Hip Fracture Database) dataset. Discussion Evidence on the optimum choice of prosthesis for hemiarthroplasty of the hip is lacking. National guidance is currently based on expert opinion rather than empirical evidence. The incidence of hip fracture is likely to continue to increase and providing high quality evidence on the optimum Cite this article: A. L. Sims. The World Hip Trauma Evaluation Study 3: Hemiarthroplasty Evaluation by Multicentre Investigation – WHITE 3: HEMI – An Abridged Protocol. Bone Joint Res 2016;5:18–25. DOI: 10.1302/2046-3758.51.2000473 PMID:26825319

  10. Arthroscopic intervention in early hip disease.

    PubMed

    McCarthy, Joseph C; Lee, Jo-Ann

    2004-12-01

    Advancement in diagnostic and therapeutic applications for hip arthroscopy have dispelled previous myths about early hip disease. Arthroscopic findings have established the following facts: Acetabular labral tears do occur; acetabular chondral lesions do exist; tears are most frequently anterior and often associated with sudden twisting or pivoting motions; and labral tears often occur in association with articular cartilage lesions of the adjacent acetabulum or femoral head, and if present for years, contribute to the progression of delamination process of the chondral cartilage. Magnetic resonance arthrography represents an improvement over conventional magnetic resonance imaging, it does have limitations when compared with direct observation. Although indications for hip arthroscopy are constantly expanding, the most common indications include: labral tears, loose bodies, chondral flap lesions of the acetabular or femoral head, synovial chondromatosis, foreign body removal, and crystalline hip arthropathy (gout, pseudogout, and others). Contraindications include conditions that limit the potential for hip distraction such as joint ankylosis, dense heterotopic bone formation, considerable protrusio, or morbid obesity. Complication rates have been reported between 0.5 and 5%, most often related to distraction and include sciatic or femoral nerve palsy, avascular necrosis, and compartment syndrome. Transient peroneal or pudendal nerve effects and chondral scuffing have been associated with difficult or prolonged distraction. Meticulous consideration to patient positioning, distraction time and portal placement are essential. Judicious patient selection and diagnostic expertise are critical to successful outcomes. Candidates for hip arthroscopy should include only those patients with mechanical symptoms (catching, locking, or buckling) that have failed to respond to conservative therapy. The extent of articular cartilage involvement has the most direct relationship

  11. Basic Hip Arthroscopy: Supine Patient Positioning and Dynamic Fluoroscopic Evaluation.

    PubMed

    Mannava, Sandeep; Howse, Elizabeth A; Stone, Austin V; Stubbs, Allston J

    2015-08-01

    Hip arthroscopy serves as both a diagnostic and therapeutic tool for the management of various conditions that afflict the hip. This article reviews the basics of hip arthroscopy by demonstrating supine patient positioning, fluoroscopic evaluation of the hip under anesthesia, and sterile preparation and draping. Careful attention to detail during the operating theater setup ensures adequate access to the various compartments of the hip to facilitate the diagnosis of disease and treatment with minimally invasive arthroscopy. Furthermore, having a routine method for patient positioning and operative setup improves patient safety, as well as operative efficiency, as the operative team becomes familiar with the surgeon's standard approach to hip arthroscopy cases.

  12. Prevention of congenital dislocation of the hip in the newborn.

    PubMed

    Miranda, L; Palomo, J M; Monzonis, J; Marti, V

    1988-01-01

    Routine examination and early treatment of any instability in the hips of newborns has recently been called into question after a period of universal agreement. The hips of 49,937 neonates were prospectively studied by a general hip screening. Every unstable hip--449 in 317 children--was immediately treated with a Von Rosen splint for a 3-month-period. Overall, satisfactory reduction of the incidence of established congenital dislocation of the hip (CDH) was achieved. Risk factors leading to unstable hips (sex, first birth, and breech birth) and the development of CDH (time of stabilization) were considered.

  13. Neuromuscular hip biomechanics and pathology in the athlete.

    PubMed

    Torry, Michael R; Schenker, Mara L; Martin, Hal D; Hogoboom, Doug; Philippon, Marc J

    2006-04-01

    Although hip arthroscopic techniques have been developed and evolved over the last 5 to 10 years to help active athletes, the mechanisms of athletic hip injuries across various sports are not well understood. The purpose of this article is to review the literature related to the osseous and ligamentous support as well as the neuromuscular control strategies associated with hip joint mechanics. The neuromuscular contributions to hip stability and mobility with respect to gait will be provided because this data represents the largest body of knowledge regarding hip function. Further, this article will present and describe probable mechanisms of injury in sporting activities most often associated with hip injury in the young athlete.

  14. Natural acetabular orientation in arthritic hips

    PubMed Central

    Goudie, S. T.; Deakin, A. H.; Deep, K.

    2015-01-01

    Objectives Acetabular component orientation in total hip arthroplasty (THA) influences results. Intra-operatively, the natural arthritic acetabulum is often used as a reference to position the acetabular component. Detailed information regarding its orientation is therefore essential. The aim of this study was to identify the acetabular inclination and anteversion in arthritic hips. Methods Acetabular inclination and anteversion in 65 symptomatic arthritic hips requiring THA were measured using a computer navigation system. All patients were Caucasian with primary osteoarthritis (29 men, 36 women). The mean age was 68 years (SD 8). Mean inclination was 50.5° (SD 7.8) in men and 52.1° (SD 6.7) in women. Mean anteversion was 8.3° (SD 8.7) in men and 14.4° (SD 11.6) in women. Results The difference between men and women in terms of anteversion was significant (p = 0.022). In 75% of hips, the natural orientation was outside the safe zone described by Lewinnek et al (anteversion 15° ± 10°; inclination 40° ± 10°). Conclusion When using the natural acetabular orientation to guide component placement, it is important to be aware of the differences between men and women, and that in up to 75% of hips natural orientation may be out of what many consider to be a safe zone. Cite this article: Bone Joint Res 2015;4:6–10. PMID:25628463

  15. Arthroscopic Treatment for External Snapping Hip

    PubMed Central

    Yoon, Jae Youn; Kwak, Hong Suk; Yoon, Kang Sup; Chang, Jae Suk

    2014-01-01

    Purpose The purpose of this study was to evaluate the clinical outcome of arthroscopic treatment for recalcitrant external snapping hip. Materials and Methods Between September 2011 and June 2013, we evaluated 7 patients (10 cases) with snapping hip who were refractory to conservative treatments for at least 3 months. Two patients (4 cases) were impossible to adduct both knees in 90°of hip flexion. Surgery was done in lateral decubitus position, under spinal anesthesia. We made 2 arthroscopic portals to operate the patients, and used cross-cutting with flap resection technique to treat the lesion. We performed additional gluteal sling release in those 2 patients (4 cases) with adduction difficulty. Average follow-up length was 19 months (range, 12-33 months). Clinical improvement was evaluated with visual analog scale (VAS), modified Harris hip score (mHHS), and also investigated for presence of limping or other complications as well. Results The VAS decreased from 6.8 (range, 6-9) preoperatively to 0.2 (range, 0-2) postoperatively, and the mHHS improved from 68.2 to 94.8 after surgery. None of the patients complained of post-operative wound problem or surgical complications. Conclusion The clinical outcome of arthroscopic treatment for recalcitrant external snapping hip was encouraging and all patients were also satisfied with the cosmetic results. PMID:27536576

  16. Trajectories of depressive symptoms after hip fracture

    PubMed Central

    Cristancho, P.; Lenze, E. J.; Avidan, M. S.; Rawson, K. S.

    2016-01-01

    Background Hip fracture is often complicated by depressive symptoms in older adults. We sought to characterize trajectories of depressive symptoms arising after hip fracture and examine their relationship with functional outcomes and walking ability. We also investigated clinical and psychosocial predictors of these trajectories. Method We enrolled 482 inpatients, aged ≥60 years, who were admitted for hip fracture repair at eight St Louis, MO area hospitals between 2008 and 2012. Participants with current depression diagnosis and/or notable cognitive impairment were excluded. Depressive symptoms and functional recovery were assessed with the Montgomery–Asberg Depression Rating Scale and Functional Recovery Score, respectively, for 52 weeks after fracture. Health, cognitive, and psychosocial variables were gathered at baseline. We modeled depressive symptoms using group-based trajectory analysis and subsequently identified correlates of trajectory group membership. Results Three trajectories emerged according to the course of depressive symptoms, which we termed ‘resilient’, ‘distressed’, and ‘depressed’. The depressed trajectory (10% of participants) experienced a persistently high level of depressive symptoms and a slower time to recover mobility than the other trajectory groups. Stressful life events prior to the fracture, current smoking, higher anxiety, less social support, antidepressant use, past depression, and type of implant predicted membership of the depressed trajectory. Conclusions Depressive symptoms arising after hip fracture are associated with poorer functional status. Clinical and psychosocial variables predicted membership of the depression trajectory. Early identification and intervention of patients in a depressive trajectory may improve functional outcomes after hip fracture. PMID:27032698

  17. Cystic lesion around the hip joint

    PubMed Central

    Yukata, Kiminori; Nakai, Sho; Goto, Tomohiro; Ikeda, Yuichi; Shimaoka, Yasunori; Yamanaka, Issei; Sairyo, Koichi; Hamawaki, Jun-ichi

    2015-01-01

    This article presents a narrative review of cystic lesions around the hip and primarily consists of 5 sections: Radiological examination, prevalence, pathogenesis, symptoms, and treatment. Cystic lesions around the hip are usually asymptomatic but may be observed incidentally on imaging examinations, such as computed tomography and magnetic resonance imaging. Some cysts may enlarge because of various pathological factors, such as trauma, osteoarthritis, rheumatoid arthritis, or total hip arthroplasty (THA), and may become symptomatic because of compression of surrounding structures, including the femoral, obturator, or sciatic nerves, external iliac or common femoral artery, femoral or external iliac vein, sigmoid colon, cecum, small bowel, ureters, and bladder. Treatment for symptomatic cystic lesions around the hip joint includes rest, nonsteroidal anti-inflammatory drug administration, needle aspiration, and surgical excision. Furthermore, when these cysts are associated with osteoarthritis, rheumatoid arthritis, and THA, primary or revision THA surgery will be necessary concurrent with cyst excision. Knowledge of the characteristic clinical appearance of cystic masses around the hip will be useful for determining specific diagnoses and treatments. PMID:26495246

  18. Hip and ankle range of motion and hip muscle strength in young female ballet dancersand controls

    PubMed Central

    Bennell, K.; Khan, K. M.; Matthews, B.; De Gruyter, M.; Cook, E.; Holzer, K.; Wark, J. D.

    1999-01-01

    OBJECTIVES: To compare the hip and ankle range of motion and hip muscle strength in 8-11 year old novice female ballet dancers and controls. METHODS: Subjects were 77 dancers and 49 controls (mean (SD) age 9.6 (0.8) and 9.6 (0.7) years respectively). Supine right active hip external rotation (ER) and internal rotation (IR) were measured using an inclinometer. A turnout protractor was used to assess standing active turnout range. The measure of ER achieved from below the hip during turnout (non-hip ER) was calculated by subtracting hip ER range from turnout range, and hip ER:IR was derived by dividing ER range by IR range. Range of right weight bearing ankle dorsiflexion was measured in a standing lunge using two methods: the distance from the foot to the wall (in centimetres) and the angle of the shank to the vertical via an inclinometer (in degrees). Right calf muscle range was measured in weight bearing using an inclinometer. A manual muscle tester was used to assess right isometric hip flexor, internal rotator, external rotator, abductor, and adductor strength. RESULTS: Dancers had less ER (p<0.05) and IR (p<0.01) range than controls but greater ER:IR (p<0.01). Although there was no difference in turnout between groups, the dancers had greater non-hip ER. Dancers had greater range of ankle dorsiflexion than controls, measured in both centimetres (p<0.01) and degrees (p<0.05), but similar calf muscle range. After controlling for body weight, controls had stronger hip muscles than dancers except for hip abductor strength which was similar. Regression analyses disclosed a moderate relation between turnout and hip ER (r = 0.40). There were no significant correlations between range of motion and training years and weekly training hours. CONCLUSIONS: Longitudinal follow up will assist in determining whether or not hip and ankle range in young dancers is genetically fixed and unable to be improved with further balletic training. 


 PMID:10522638

  19. Impact of hip fracture on mortality: a cohort study in hip fracture discordant identical twins.

    PubMed

    Michaëlsson, Karl; Nordström, Peter; Nordström, Anna; Garmo, Hans; Byberg, Liisa; Pedersen, Nancy L; Melhus, Håkan

    2014-02-01

    Several studies have shown a long-lasting higher mortality after hip fracture, but the reasons for the excess risk are not well understood. We aimed to determine whether a higher mortality after hip fracture exists when controlling for genetic constitution, shared environment, comorbidity, and lifestyle by use of a nationwide cohort study in hip fracture discordant monozygotic twins. All 286 identical Swedish twin pairs discordant for hip fracture (1972 to 2010) were identified. Comorbidity and lifestyle information was retrieved by registers and questionnaire information. We used intrapair Cox regression to compute multivariable-adjusted hazard ratios (HRs) for death. During follow-up, 143 twins with a hip fracture died (50%) compared with 101 twins (35%) without a hip fracture. Through the first year after hip fracture, the rate of death increased fourfold in women (HR = 3.71; 95% confidence interval [CI] 1.32-10.40) and sevenfold in men (HR = 6.67; 95% CI 1.47-30.13). The increased rate in women only persisted during the first year after hip fracture (HR after 1 year = 0.99; 95% CI 0.66-1.50), whereas the corresponding HR in men was 2.58 (95% CI 1.02-6.62). The higher risk in men after the hip fracture event was successively attenuated during follow-up. After 5 years, the hazard ratio in men with a hip fracture was 1.19 (95% CI 0.29-4.90). On average, the hip fracture contributed to 0.9 years of life lost in women (95% CI 0.06-1.7) and 2.7 years in men (95% CI 1.7-3.7). The potential years of life lost associated with the hip fracture was especially pronounced in older men (>75 years), with an average loss of 47% (95% CI 31-61) of the expected remaining lifetime. We conclude that both women and men display a higher mortality after hip fracture independent of genes, comorbidity, and lifestyle. PMID:23821464

  20. HIP10680/HIP10679: a visual binary in the beta Pictoris association with the fastest rotating member

    NASA Astrophysics Data System (ADS)

    Messina, S.; Hentunen, V.-P.; Zambelli, R.

    2015-06-01

    We present the results of a multi-filter photometric monitoring of the wide binary HIP10680/HIP10679 WE found both component to be variable with amplitude up to delta V = 0.03 mag in the case of HIP10680 and delta V = 0.07 mag in the case of HIP10679. We could measure the rotation periods P = 0.2396 d of the hotter F5V component HIP10680 and P = 0.777 d of the cooler G5V component HIP10679. We found that the rotation axes of both components are aligned with an inclination i = 10.