Hip resurfacing (HR) is an alternative option to total hip arthroplasty (THA) in a population of selected patients (young and/or active).
The short-term survivorship rate is as least as good as that for THA with no abnormal increase in serum metal ion levels.
Materials and methods
A continuous prospective series of 502 hip resurfacings in 481 patients mean age 48.7 years old (±10.3; 18–68) (Conserve Plus, Wright Medical Technology) was analyzed clinically, radiologically and biologically (total blood chrome, cobalt and titanium metal ion levels). Mean follow up was 4.1 years (1.9–4.9).
There were no dislocations. There were 5 cases of revision surgery with component replacement (including 2 infections). Implant survivorship using implant removal as the criteria (excluding infection) was 99.4% at 4 years (CI 95%: 98.1–99.8). The evaluation of metal ion levels showed a significant increase in cobalt from a preoperative level of 0.24μg/L (0.01–3.6) to 0.86μg/L (0.01–5.7) at the final follow-up (P<0.001). Chrome and titanium levels went from 0.68μg/L (0.01–4.4) and 2.36μg/L (0.39–7) to 1.28μg/L (0.1–5.5) and 4.49μg/L (1.29–8.21) respectively (P<0.001). All clinical scores had significantly improved at the final follow-up. Mean frontal plane cup inclination was 42.7° (35–62).
In a selected population of young and/or active patients, the short-term results of hip resurfacing are excellent. At the postoperative 4-year follow-up the rate of complications (in particular the absence of dislocations) was less than that for THA in young and/or active patients. Certain conditions must be respected to obtain these results; frontal plane cup inclination of between 40 and 45°, a femoral head diameter of at least 48mm and good quality femoral bone.
Level of evidence
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Keywords : Femoral head diameter, Hip resurfacing, Ion levels, Survival