1 . The results of transplanting the greater trochanter in 225 "low-friction" arthroplasties of the hip have been examined.

2. Non-union occurred in an average of 7 per cent of cases.

3. When non-union occurred the results still showed improvement.

4. Four different methods of fixation were used, of which that using two wires, crossed in the horizontal and coronal planes, never failed to secure union.

5. Transplantation of the greater trochanter to the best position is only possible if the neck of the femur is shortened or if the centre of motion of the arthroplasty is displaced medially by deepening the acetabulum, or by a combination of both.

6. In the best position the transplanted trochanter considerably improved active abduction against gravity.