Abstract
In revision surgery with proximal femoral bone loss, progressive bone atrophy due to stress shielding remains a concern. We compared 2-year radiological results between two types of cementless long titanium stems with different configurations and surface coatings. Of 17 hips implanted with a wholly hydroxyapatite-coated stem, 12 (71%) exhibited stress shielding of the second degree or higher according to Engh's criteria, and the mean relative bone mass index decreased from 22.1% pre-operatively to 14.6% at 2 years post-operatively. In 23 hips implanted with a sand-blasted, conically shaped stem, no hip showed stress shielding of the second degree or higher. The mean relative bone mass index increased from 21.6% to 31.4%. These results indicate that the configuration and surface coating of the stem have a significant influence on proximal bone remodelling after revision surgery.