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.

80 patients undergoing primary uncemented hip arthroplasty were randomized to receive surgery with the regular omnifit-HA 1017 hydroxyapatite (HA)-coated stem or the shorter omnifit-HA 1090 hydroxyapatite-coated stem. Over 24 months, the patients that received the shorter stem demonstrated increased proximal fixation compared to the regular stem patients. However, patients that received the short stem experienced more pain than the regular stem patients. It was therefore concluded that, although the short stem displays increased proximal fixation, it may lead to diminished mechanical stability.