Transtrochanteric curved varus osteotomy was designed to avoid some of the disadvantages of varus wedge osteotomy, such as post-operative leg-length discrepancy. In this retrospective study we investigated the leg-length discrepancy and clinical outcome after transtrochanteric curved varus osteotomy undertaken in patients with osteonecrosis of the femoral head. Between January 1993 and March 2004, this osteotomy was performed in 42 hips of 36 patients with osteonecrosis of the femoral head. There were 15 males and 21 females with a mean age at surgery of 34 years (15 to 68). The mean follow-up was 5.9 years (2.0 to 12.5). The mean pre-operative Harris hip score was 64.0 (43 to 85) points, which improved to a mean of 88.7 (58 to 100) points at final follow-up. The mean varus angulation post-operatively was 25° (12° to 38°) and the post-operative mean leg-length discrepancy was 13 mm (4 to 25). The post-operative leg-length discrepancy showed a strong correlation with varus angulation (Pearson’s correlation coefficient; r = 0.9530, p < 0.0001), which may be useful for predicting the leg-length discrepancy which can occur even after transtrochanteric curved varus osteotomy.

Our study describes the mid-term clinical results of the use of transtrochanteric valgus osteotomy (TVO) for the treatment of osteoarthritis of the hip secondary to acetabular dysplasia. The operation included valgus displacement at the level of the lesser trochanter, and lateral displacement of the greater trochanter by inserting a wedge of bone. We reviewed 70 hips. The mean age of the patients at operation was 44 years (14 to 59). Most (90%) had advanced osteoarthritis.

The scores for pain and gait had improved significantly at a mean follow-up of 9.4 years. The rate of survival until an endpoint of a further operation during a follow-up of ten years was 82%. The survival rate was 95% in patients with unilateral involvement who were less than 50 years of age at operation. TVO is a useful form of treatment for advanced osteoarthritis of the hip, particularly in young patients with unilateral disease.

We have studied the correlation between the prevention of progressive collapse and the ratio of the intact articular surface of the femoral head, after transtrochanteric rotational osteotomy for osteonecrosis. We used probit analysis on 125 hips in order to assess the ratio necessary to prevent progressive radiological collapse over a ten-year period. The results show that a minimum postoperative intact ratio of 34% was required. This critical ratio may be useful for surgical planning and in assessing the natural history of the condition.