Hydroxyapatite in total hip arthroplasty: five-year clinical experience.

Excellent clinical and radiographic results are seen with HA-coated femoral components at 5-year follow up. These stems are well fixed proximally, and the transmission of stress is noted to occur at the transition from the coated to uncoated stem. Longer follow up is needed to determine if the currently stable HA-coated implants will become threatened by wear debris and subsequent osteolysis, as has been the case in many long-term studies of other hip implants.