Clinical and radiographic outcomes of 139 hips with articular surface replacement total hip arthroplasty*.

Background: The articular surface replacement (ASR) total hip arthroplasty (THA) was recently recalled from the market due to high failure rates. This modality was used frequently by surgeons at our medical center.

Objectives: To assess the clinical and radiographic outcomes in patients following the surgery and determine the revision rate in our cohort.

Methods: Between 2007 and 2010 139 hips were operated on and evaluated in our clinic. All patients underwent a clinical interview, function and pain evaluation, as well as physical examination and radiographic evaluation. When necessary, patients were sent for further tests, such as measuring cobalt-chromium levels and magnetic resonance hip imaging.

Results: With an average follow-up of 42 months the revision rate was 2% (3/139). Patients reported alleviation of pain (from 8.8 to 1.7 on the Visual Analog Scale, P < 0.001), good functional outcomes on the Harris Hip Score, and improved quality of life. Overall satisfaction was 7.86 on the reversed VAS. For patients who required further tests, clinical and radiographic outcomes were significantly poorer than for the rest of the cohort. Average blood ion levels were high above the normal (cobalt 31.39 ppb, chromium 13.32 ppb), and the rate of inflammatory collection compatible with pseudotumors on MRI was 57%.

Discussion: While our study favors the use of the ASR implant both clinically and radiographically, some patients with abnormal ion levels and inflammatory collections on MRI might require revision in the future.