Thigh pain in cementless total hip arthroplasty. A comparison of two systems at 2 years' follow-up.

Cementless total hip arthroplasties using 110 porous-coated anatomic (PCA) and 105 consecutive Mallory-Head (MH) prostheses were reviewed using prospectively gathered clinical data and a detailed radiographic analysis. In an earlier experience with the PCA, 13% of patients experienced thigh pain at 1 year and 23% at 2 years. Positive radiographic correlates with thigh pain included subsidence, distal cortical hypertrophy, a tight diaphyseal fit, and stem tip sclerosis. In the current MH study group, the incidence of thigh pain was 7% at 1 year and 3% at 2 years. No radiographic findings correlated positively with thigh pain. The results of this short-term clinical comparison suggest that a long, straight, tapered design offered better initial stability than its anatomic counterpart as reflected in the much lower incidence of thigh pain. These results may translate into improved osseous integration and long-term success.