Nearly 5 per cent of 728 hips showed separation and migration of the trochanteric fragment after total hip replacement using the transtrochanteric approach and a cruciate two-wire technique of reattachment. In the 728 consecutive hips, thirty-five trochanters showed separation and eighteen patients had a positive Trendelenburg test. The abductor weakness was correlated with the amount of separation especially if it exceeded two centimeters. Trochanteric separation was attributed to osteoporosis or poor technique in all but two hips, and trauma was implicated in one.