The ASR (articular surface replacement) XL (DePuy, Warsaw, Ind) metal-on-metal hip arthroplasty offers the advantage of stability and increased motion. However, an alarming number of early failures prompted the evaluation of patients treated with this system. A prospective study of patients who underwent arthroplasty with the ASR XL system was performed. Patients with 2-year follow-up or any revision were included. Failure rates, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and radiographs were evaluated. Ninety-five patients (105 hips) were included. There were 16 revisions. Thirteen (12%) were aseptic acetabular failures. Eight were revised for aseptic loosening; 4, for metallosis; 1, for malposition; 2, for infection; and 1, for periprosthetic fracture. Mean time to revision was 1.6 years (0.18-3.4 years). The ASR XL with a revision rate of 12% is the second reported 1 piece metal-on-metal system with a significant failure rate at early follow-up. This particular class of implants has inherent design flaws that lead to early failure.
"The introduction of new implants in orthopedic surgery is intended to ultimately benefit patients and to improve clinical outcomes. However, new implants and new technology often produce unforeseen problems and generate inferior outcomes compared to traditional/preexisting technologies        . Such problems can only be discovered through methodical analysis of early and mid-term clinical outcome data retrieved from properly conducted studies. "
[Show abstract][Hide abstract] ABSTRACT: Bearing surface wear remains a potential concern amongst younger patients undergoing total knee arthroplasty (TKA). Because of the potential for lower prosthetic wear rates, oxidized zirconium is a potentially attractive bearing surface for TKA in young, active patients. This material is also well suited for patients with suspected nickel sensitivities as it has no measurable nickel content, in contrast to standard femoral bearings made of cobalt-chromium alloys. Although in vitro testing on knee wear simulators has demonstrated favorable wear characteristics of oxidized zirconium compared to traditional cobalt-chrome bearings, in vivo clinical outcome data with this novel bearing surface are sparse.
We retrospectively reviewed 109 consecutive TKAs in 82 patients at a minimum of five years postoperatively to determine prosthetic survivorship and to assess whether any adverse clinical consequences could be attributed to this bearing. Knees were evaluated with Knee Society scores, UCLA activity scores, clinical examinations, and radiographs. The mean age for this cohort was 58.7years.
Survivorship free of bearing related complications was 100% at a minimum of five years post-surgery. There were no revisions for loosening, osteolysis, implant failure, or deep infection. There were no knees with radiographic failure, visible wear, loosening, or osteolysis.
Oxidized zirconium remains an attractive option for patients with nickel sensitivities and in those patients at risk for prosthetic wear due to young age or high activity levels.
The Knee 08/2013; 21(1). DOI:10.1016/j.knee.2013.08.015 · 1.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of our study was to determine if authors with conflicts of interest are less likely to report negative study outcomes in metal-on-metal total hip arthroplasty. We performed a systematic review of 3 major orthopedic journals for articles related to metal-on-metal total hip arthroplasty over 12 years. A total of 64 studies reported clinical outcomes and were included. Reviewers assigned a positive, neutral, or negative label. Each study was noted for the presence of absence of a financial conflict. There was a significant trend from positive to negative study outcomes over time (P = .015). A similar negative trend was seen in studies written by authors with financial disclosures (P = .021). Authors with financial conflicts have contributed to the increase in negative outcomes reported in the literature.
The Journal of arthroplasty 06/2012; 27(8 Suppl):41-5.e1. DOI:10.1016/j.arth.2012.03.060 · 2.67 Impact Factor
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