CERAMIC-ON-CERAMIC HIP RESURFACING ARTHROPLASTY (RECERF): RADIOSTEREOMETRIC ANALYSIS OF IMPLANT MIGRATION AT ONE YEAR

Hip Resurfacing Arthroplasty (HRA) provides an alternative to Total Hip Arthroplasty (THA) for a select group of patients with end stage hip osteoarthritis. Compared to THA, HRA is a bone conserving procedure that has shown to reduce dislocation rates and improve return to sport and physically demanding jobs. The current licensed implant designs utilise a cobalt chromium, metal on metal (MOM) bearing which raises concerns with metal ion toxicity and adverse reaction to metal debris. Here we report 12-month radiostereometric (RSA) analysis of the MatOrtho ReCerf all ceramic HRA which provides an alternative to conventional MOM designs. To date 25 patients have been recruited to the study at Freeman Hospital, Newcastle and 12 patients have received their 12-month RSA exams. The study will conclude when 24-month data is available for the intended 30 cases. All RSA exams were analysed with model-based RSA by measuring cup and head migration via tantalum beads implanted during surgery on serial radiographs immediately post operatively and at 6, 12 and 24-months. Mean cup total translation at 12-months was 0.391 mm (95% CI 0.215 to 0.567 mm). Medial translation 0.109 mm (95% CI -0.013 to 0.231 mm), superior translation 0.118 mm (95% CI -0.041 to 0.276 mm), anterior translation 0.172 mm (95% CI -0.001 to 0.346 mm). Mean cup anteversion rotation 0.362 deg (95% CI -0.079 to 0.802 deg), inclination rotation -0.258 deg (95% CI - 0.516 to 0.000 deg). Head migration results are also available for presentation. The interim results from this 2-year RSA study suggests that the MatOrtho ReCerf HRA will have acceptably low rates of cup migration and be comparable to other prosthesis with proven low incidence of aseptic loosening. Whilst there is no 2-year data available yet, the rate of migration shown for all migration parameters decreased in the second 6-month period. Longer term follow up and completion of this study is required to substantiate these interim findings and support the wider use of the ReCerf HRA as an alternative to MOM HRA or THA.