Promising results for resurfacing with Conserve® Plus in patients less than 50 years of age
Clin Orthop Relat Res. 2007 Jul; 460: 159-64.
Amstutz HC
Ball ST
Le Duff MJ
Dorey FJ
Younger patients are at a higher risk of early failure with a conventional stemmed THA and modern generation resurfacing THA is an alternate form of treatment that could be well suited for this patient population in term of prosthetic survival and clinical results.
Resurfacing THA is an attractive treatment option for young patients because it saves the femoral head and is easily revisable. We assessed the clinical outcome of metal-on-metal hybrid total hip resurfacing for the treatment of 295 patients (350 hips) younger than 50 years of age (average, 41.2 years) and compared these results with those of patients 50 years or older (average, 57.4 years) at the time of surgery who were implanted with the same design. 75% of the patients were male. The average followup was 5.5 years; UCLA hip scores improved to 9.4 for pain; 9.6 for walking; 9.5 for function; and 7.6 for activity. We found no differences in survivorship between the younger and older patients, and postoperative clinical scores related to the patients’ physical health were comparable. There was no acetabular component loosening. Ten hips (2.8%) were revised for femoral aseptic loosening and one for femoral neck fracture. The study of intraoperative photographs and failed implant retrievals triggered surgical changes to improve bone preparation and increase femoral fixation area (second-generation fixation technique). In this subset (the last 190 hips of our series), there were only one revision (0.5% revision rate) and two asymptomatic stem radiolucencies (1.1%). There have been no failures when the metaphyseal stem was cemented, an adjunctive step we recommend in patients with cystic degeneration or diminished bone quality along with avoiding high-impact activities. We do not recommend cementing the metaphyseal femoral stem in patients with a large fixation area and good bone quality because these hips have performed well without stem cementation and because the potential adverse long-term effects of cementing the stem on stress shielding are still unclear.
Patient selection is an important factor in optimizing outcomes, and young adults with good bone quality had the best results. Surgical technique played a critical role, particularly in patients with risk factors. The 5-year survivorship of hips with good bone quality was 97.8%. There has been no femoral component loosening when the femoral stems were cemented irrespective of bone quality. Metal-on-metal resurfacing THA of the hip performs well at short to midterm followup in young, active adults despite high activity levels.