Early Failure of Articular Surface Replacement XL Total Hip Arthroplasty
ABSTRACT 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.
SourceAvailable from: Gabrielle Kelly[Show abstract] [Hide abstract]
ABSTRACT: Following the global recall of all ASR metal on metal hip products, our aim was to correlate MRI findings with acetabular inclination angles and metal ion levels in patients with these implants. Both cobalt and chromium levels were significantly higher in the presence of a periprosthetic fluid collection. There was no association between the presence of a periprosthetic mass, bone marrow oedema, trochanteric bursitis or greater levels of abductor muscle destruction for cobalt or chromium. There was no association between the level of periprosthetic tissue reaction and the acetabular inclination angle with any of the pathologies identified on MRI. The relationship between MRI pathology, metal ion levels and acetabular inclination angles in patients with ASR implants remains unclear adding to the complexity of managing patients.The Journal of arthroplasty 03/2014; 29(8). DOI:10.1016/j.arth.2014.03.030 · 2.37 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Taper junctions of large diameter metal-on-metal femoral heads and femoral stems were described as metal ion generator due to accelerated wear and corrosion. However, literature about the Articular Surface Replacement™ (ASR™) total hip arthroplasty (THA) invariably deals with stems manufactured by DePuy Orthopedics (Warsaw, IN, USA). Nothing is known whether different stems with common 12/14mm tapers affect failure rate or ion release. 99 ASR™ THA (88 patients) implanted with CoxaFit® or ARGE Geradschaft® stems (K-Implant, Hannover, Germany) were retrospectively analyzed. After a mean follow-up of 3.5 years revision rate was 24.5%, mostly due to adverse reaction to metal debris (ARMD). CT-scan revealed component loosening in 10.3% and pseudotumoral lesions in 12.6%. Elevated ion concentrations (> 7μg/l) were found in 38.6%. ARMD was even found in asymptomatic patients with ion levels < 7μg/l.The Journal of Arthroplasty 11/2014; 29(11). DOI:10.1016/j.arth.2014.06.025 · 2.37 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: In this study, periacetabular pressures produced by different acetabular liner geometries were analyzed using Finite Element Method. The cup models consist of hemispherical metal shells fitted with normal and different chamfered polyethylene liner geometries, with the same degree of femoral head coverage. The aim of this study was to understand the influence of the design parameters of the chamfered liners, which are primarily designed to increase the range of motion (ROM) of the hip joint and reduce the risk of impingement, on the acetabular contact pressures. The cup models were loaded to simulate periacetabular pressures during routine activities. The results show that the difference in contact pressure between the normal and chamfer models was not substantial in the given orientation of the cup. Also, the increase of the chamfer angle has a small influence on the maximum contact pressures, although that could be also dependent on the reduction of the polyethylene thickness. Pre-clinical testing of total hip prostheses using Finite Element Method enables the evaluation of contact pressures and stress distribution, and proves to be a valuable tool to analyze the parameters reducing the contact pressure.Key Engineering Materials 03/2014; 601:159-162. DOI:10.4028/www.scientific.net/KEM.601.159