Evaluation of joint thickness in the hip before and after osteotomy using three-dimensional modelling.

Joint thickness was assessed using three-dimensional modelling techniques before and after the Bombelli intertrochanteric valgus-extension osteotomy. Before operation, the average thickness of the entire hemispherical surface was 2.3 mm, which was significantly thinner than that of the controls. After operation, 11 of 12 patients showed an average increase in thickness to 3 mm, nearly equal to that of the controls, and this was accompanied by clinical improvement.