Medium-term results of hip arthroplasty with ASR XL (DePuy)

Abstract

The purpose - to identify factors affect on instability and to access the medium-term survivorship of metal-on-metal X-large heads total hip prostheses. Material and methods. From January 2007 March 2009 we performed 134 ASR XL head - Corail total hip arthroplasties in 119 patients. The medium-term results were studied in 94 (105 hips). Mean follow-up was 76±3 months. Radiological evaluation was carried out in standard views. Clinical and functional results were accessed with Harris Hip Score. We determined metal ions concentration in whole blood with atomic absorption spectrometry (AAS) and mass spectrometry in the induced coupled plasma (ICP-MS). Changes in periprosthetic tissues were studied at high field magnetic resonance imaging (MRI) with subsequent histological confirmation. “Gamma test” was applied for statistic analysis revision risk factors. Results. Medium-term survivorship of studied implants amounted to 85.5% (95% CI 78.7% to 92.3%). Average ions concentration in the whole blood of amounted to 3.2 ppb and 2.9 ppb foe Co and Cr respectively Specific risk factors of instability were gender (female), small size of the cups, and high angle of abduction (>45°). The main reason for revision was cup loosening (over 50%). Conclusions. Patients in this cohort are in a great danger of early aseptic loosening, especially in the presence of specific risk factors. So the annual monitoring is considered mandatory for them. The indications for revision surgery are not only the evident implant instability, but also the pathological changes in periprosthetic tissues associated with high ions level in whole blood.

Keywords

• пара трения металл-металл
• выживаемость эндопротезов
• ревизионная артропластика
• metal-on-metal implants
• medium-term survivorship
• revision arthroplasty