The Natural History of the Periacetabular Fragment Following Ganz Osteotomy

The vascularity of the acetabular free fragment in Ganz osteotomies has remained a concern. This study aims to assess the role of MR imaging in the postoperative evaluation of Ganz osteotomies. Twenty patients (19 females, 1 male), average age 24 years (range, 12–36 years), had sequential magnetic resonance imaging studies of the pelvis at 6 weeks and 6 months following Ganz osteotomies. Normal healing with no evidence of periosteotomy edema was seen in 17 patients at 6 weeks. Three patients showed evidence of reduced vascularity. In two of these, there were focal changes suggestive of subclinical ischemia. The other had gross signal changes in the osteotomy fragment suggestive of diffuse ischemia. The patients with focal changes were asymptomatic and had normal 6-month scans. The patient with diffuse changes complained of persistent groin pain, which resolved after 4 months. The 6-month scan showed some persistent vascular changes. The scan at 1 year showed complete resolution. The study suggests that Ganz osteotomy has minimal effect on the vascularity of the acetabular free fragment. (Journal of Surgical Orthopaedic Advances 13(2):91–93, 2004)