Hemiresurfacing for femoral head osteonecrosis.

A modified THARIES femoral resurfacing component was used as a hemiarthroplasty in 11 young adult patients (12 hips) with osteonecrosis. The mean follow-up period was 39 months (range, 24-62 months). In all of the hips, the necrosis had advanced to the stage of subchondral femoral head fracture and segmental depression, but there was a relatively normal acetabulum. Ten hips have maintained satisfactory improvement of UCLA pain, walking, and function hip scores. One hip was revised to an uncemented total replacement, and one has some residual pain. No case failed because of component loosening. The modified femoral THARIES component was used as a preferable alternative to unipolar or bipolar hemiarthroplasty, and the results appear to be comparable in this difficult group of patients. Hemiresurfacing was conceived not as a definitive procedure but rather as a time-buying measure to improve symptoms and function and to allow the performance of a technically uncompromised total hip arthroplasty at a future date.