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Down's syndrome is associated with a number of musculoskeletal abnormalities, some of which predispose patients to early symptomatic arthritis of the hip. The purpose of the present study was to review the general and hip-specific factors potentially compromising total hip replacement (THR) in patients with Down's syndrome, as well as to summarise both the surgical techniques that may anticipate the potential adverse impact of these factors and the clinical results reported to date. A search of the literature was performed, and the findings further informed by the authors' clinical experience, as well as that of the hip replacement in Down Syndrome study group. The general factors identified include a high incidence of ligamentous laxity, as well as associated muscle hypotonia and gait abnormalities. Hip-specific factors include: a high incidence of hip dysplasia, as well as a number of other acetabular, femoral and combined femoroacetabular anatomical variations. Four studies encompassing 42 hips, which reported the clinical outcomes of THR in patients with Down's syndrome, were identified. All patients were successfully treated with standard acetabular and femoral components. The use of supplementary acetabular screw fixation to enhance component stability was frequently reported. The use of constrained liners to treat intra-operative instability occurred in eight hips. Survival rates of between 81% and 100% at a mean follow-up of 105 months (6 to 292) are encouraging. Overall, while THR in patients with Down's syndrome does present some unique challenges, the overall clinical results are good, providing these patients with reliable pain relief and good function.

A man presented with hypothyroidism, dilated cardiomyopathy, a pericardial effusion, liver failure, and polycythaemia. He had a history of bilateral hip replacements and new-onset hip pain. The patient progressed to develop shock. Given his acutely profound illness and constellation of symptoms, as well as the history of hip replacement, a diagnosis of cobalt toxicity was made., (Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Total hip arthroplasty has shown excellent results in decreasing pain and improving function in patients with degenerative disease of the hip. Improvements in prosthetic materials, designs and implant fixation have now resulted in wear of the bearing surface being the limitation of this technology, and a number of hard-on-hard couples have been introduced to address this concern. The purpose of this article is to review the origins, development, survival rates and potential advantages and disadvantages of the following hard-on-hard bearings for total hip arthroplasty: metal-on-metal standard total hip arthroplasty; metal-on-metal hip resurfacing arthroplasty, ceramic-on-ceramic total hip arthroplasty; and ceramic-on-metal bearings. Improvements in the manufacturing of metal-on-metal bearings over the past 50 years have resulted in implants that provide low wear rates and allow for the use of large femoral heads. However, concerns remain regarding elevated serum metal ion levels, potential teratogenic effects and potentially devastating adverse local tissue reactions, whose incidence and pathogenesis remains unclear. Modern total hip resurfacing has shown excellent outcomes over 10 years in the hands of experienced surgeons. Current ceramic-on-ceramic bearings have demonstrated excellent survival with exceptionally low wear rates and virtually no local adverse effects. Concerns remain for insertional chipping, in vivo fracture and the variable incidence of squeaking. Contemporary ceramic-on-metal interfaces are in the early stages of clinical use, with little data reported to date. Hard-on-hard bearings for total hip arthroplasty have improved dramatically over the past 50 years. As bearing designs continue to improve with new and modified materials and improved manufacturing techniques, it is likely that the use of hard-on-hard bearings will continue to increase, especially in young and active patients.

Objective: Although standard total hip arthroplasties have a long and successful history as the standard of care for advanced, symptomatic osteoarthritis, there is increasing patient demand and surgeon interest in femoral bone conserving resurfacing alternatives. The purpose of this study was to assess the state of the research that directly compares the outcomes of conventional total hip arthroplasty procedures with the current generation of metal-on-metal resurfacing hip arthroplasties., Methods: A comprehensive review was performed of the published literature that directly compared total hip arthroplasty and resurfacing hip arthroplasty and that considered basic science, radiographic, and clinical studies., Results: Of the basic science studies, two investigations found evidence that favored total hip arthroplasty, while three favored resurfacing hip arthroplasty. For the clinical studies, all reports showed that resurfacing hip arthroplasty had similar or better outcomes than total hip arthroplasty at short- to midterm follow-up. The gait studies suggest that resurfacing provides a more natural gait than conventional total hip arthroplasty., Conclusions: While there is still much debate and room for additional research on this topic, multiple midterm clinical results suggest that resurfacing hip arthroplasty represents a safe, effective alternative to conventional total hip arthroplasty, especially for younger, active patients.

Background: Some studies have suggested that resurfacing patients are generally more active postoperatively than their conventional total hip arthroplasty (THA)counterparts, but controversy remains over whether this is a reflection of preferential use of resurfacing for younger and higher-activity patients. We hypothesized that, when controlling for preoperative activity levels, in addition to relevant clinical and demographic factors, resurfacing provides similar results to conventional hip arthroplasty., Materials and Methods: The specific question asked was whether resurfacing patients had differences in postoperative activity level, clinical outcomes, or rate of revisions, as compared to a matched cohort of patients treated with conventional THA. Thirty-three patients (23 men and 10 women) who were treated with resurfacing arthroplasties were matched to a cohort of patients who underwent conventional hip arthroplasty by gender, age, body mass index (BMI), and preoperative activity level. Mean preoperative Harris hip scores and length of follow-up were similar for the two groups. Postoperative weighted activity scores, Harris hip scores, patient satisfaction score, pain scores, and revision rates were evaluated at a mean final follow-up of 42 months (range, 25 to 68 months) for the resurfacing group and 45 months (range, 24 to 67 months) for the conventional hip group, and analyzed for differences., Results: At final follow-up, activity levels were significantly higher in the resurfacing group, with a mean weighted activity score of 10.0 points (range, 1.0 to 27.5 points), as compared to a mean score of 5.3 points (range, 0 to 12.0 points) in the THA group. Mean Harris hip scores, patients satisfaction scores, and pain scores were similar for both groups. There were no revisions in either group., Conclusions: The results of this study suggest that patients treated with hip resurfacing arthroplasty have a significantly higher postoperative activity level, as compared to those treated with conventional THA, when controlled for preoperative factors.