Comparison of two hydroxyapatite-coated femoral stems - Clinical, functional, and bone densitometry evaluation of patients randomized to a regular or modified hydroxyapatite-coated stem aimed at proximal fixation

Clinical function, bone mineral density (BMD), and radiographs of 80 randomly allocated, hydroxyapatite-coated femoral stems of two differing lengths were studied for 2 years. The short stein was optimized for proximal fixation. The predictive value of bone densitometry was also Studied. After 2 years, significantly more bone apposition and a higher BMD percentage were observed in Gruen zone 7 of the short stem. We Conclude that stern design can be enhanced to achieve more proximal fixation. However, We found a higher incidence of pain with the short stem, indicating a trade-off between increased proximal fixation and diminished overall mechanical stability. No strong correlations between clinical function and radiographic evaluation of remodeling were found with BMD, suggesting that dual-energy x-ray absorptiometry has no predictive value for short-term clinical outcome.