The results of medial displacement osteotomy for unstable intertrochanteric fractures demonstrate that instability exists whenever there is lack of continuity of bone cortex on opposing surfaces of the 2 main fragments after reduction of the fracture. In 88 patients, 5 were lost to follow-up; 83 were reviewed personally by the authors at an average follow-up period of 27 months; the complication rate (both local and general) was high. Eight per cent showed non-union of the fracture; 13% developed deep infection (2 suffered from septicemia). Fifteen of 83 patients required a second operation. The mortality rate at 6 months was 13%, owing to heart failure, bronchopneumonia or thromboembolism. Of the 56 living, only 24 (43%) demonstrated a good functional result. Medial displacement osteotomy should be combined with a sliding screw-plate device. Without a sliding screw plate, medial displacement osteotomy for unstable intertrochanteric fractures of the femur may not be as successful as would appear from reports in the literature.