Proximal/distal mismatch: type A and C femurs.

Femoral deformity in primary total hip arthroplasty can make restoration of joint biomechanics difficult. The S-ROM (DePuy Orthopaedics Inc., Warsaw, Ind) prosthesis' modular design allows for independent matching of diaphyseal and metaphyseal anatomy. Corrective osteotomy may also be performed because the stem achieves both proximal and distal stability, which resists the micromotion and torsional loads that would otherwise prevent ingrowth. Seventy-three hips were reviewed at a minimum of 10 years' follow-up. Osteolysis was common, occurring in 55% of hips, but no osteolysis distal to the stem/sleeve junction was present. At mean 12 years' follow-up, the stem remains stable and no failures of the modular junction have been reported.