Duration of symptoms and outcome of hemiresurfacing for hip osteonecrosis

Thirty-seven hips with Ficat Stage LI, III, or early TV osteonecrosis were treated with hemiresurfacing. The purpose of this study is to analyze speci fically the clinical and radiographic results of patients who had hemiresur facing to refine the indications for the procedure and identify factors sub stantially affecting clinical outcome and survivorship. At an average follo wup of 6.5 years, the average University of California Los Angeles hip scor es for pain, walking, function, and activity improved significantly from 4. 3, 6.0, 5.3, and 4.2 to 8.0, 8.8, 7.9, and 5.8, The overall survivorship wa s 79%, 59%, and 45% at 5, 10, and 15 years. Eleven hips have been converted : 10 hips for acetabular cartilage wear and one hip for femoral loosening. The average time to conversion was 7.5 years. A longer duration of symptoms before surgery (16.6 months versus 12.1 months) was associated with a wors e acetabular cartilage grading and suggested a relationship with a shorter time to conversion, although the difference was not statistically significa nt at the 5% level. Survivorship is better when preoperative symptoms are p resent for 1 year or less, possibly because the articular cartilage is heal thier. When necessary, conversion to total hip replacement can be done with out adverse results.