RESUMEN
Osteonecrosis of the femoral head affects mainly young patients with high functional needs this increases the risk of dislocation. Dual mobility cups known for low rate of dislocation and high mobility range seems indicated. We evaluate functional efficiency, survival and dislocation rate of dual mobility cup for total hip arthroplasty for osteonecrosis in young patients. Monocentric retrospective clinical study, from 2000 to 2008. With a clinical analysis in pre-operative and over ten years of follow-up of one cohort of patients under 55 years old with an indication of THA for ONFH. The judgement criteria was: clinical scores at the maximal follow-up, the dislocation rate, and the cumulate survival rate over ten years follow-up. Forty THA in 31 patients, nine bilateral cases, 23 males and eight females with average age of 44 (±4) years old. In pre-operative: PMA 11 (±3.3), HHS 50,8 (±15.5). At the final follow-up of 129.8 (±33.8) months: PMA (17.4 ± 1.12), HHS (95.7 ± 6.9), no dislocation. We had 11 deaths on average at 95.2 ± 47.3 months. The cumulate survival rate over ten years follow-up is 100% without revisions or long-term dislocation. Analysis concludes to very significant functional improvement without any dislocation despite the young population with high level of activity. Thus, dual mobility cups is a reliable choice preventing dislocation with a very good survival rate without premature wear, preserving mobility and activity.