TWENTY-ONE YEARS OF EXPERIENCE WITH HEMI-SURFACE ARTHROPLASTY FOR OSTEONECROSIS OF THE HIPS. IMPROVING PREDICTABILITY OF CLINICAL RESULTS
Amstutz, HC, Beaule PE, Schmalzried TP, Leduff, MJ

Introduction: THA results for ON are not satisfactory. Among bone-preserving procedures for Ficat Staff III and IV ON, hemi-surface arthroplasty has been our preferred method of treatment.

Materials and Methods: 59 hips with Ficat Staff II, III, or early IV ON. Mean age was 33.9 (18-52) and 76% of the patients were males.

Results: Mean F/U 8.4 years (1.0-21.5), no dislocations, femoral neck fractures, or osteolysis. Mean UCLA hip scores for pain, walking, function, and activity improved to 8.2, 8.8, 7.7, and 5.8. Survivorship was 81%, 57% and 40% at 5, 10, and 15 years. Fourteen (14) hips were converted: 12 acetabular cartilage wear, 1 femoral loosening and 1 sepsis. Mean time to conversion 7.0 years. Longer duration of symptoms before surgery was associated with worse acetabular cartilage grading.

Discussion: 3 patients have passed the 20 year landmark. Survivorship is better when preoperative symptoms are present for 1 year or less. When necessary, conversation to total hip replacement is similar to primary THA.