Osteonecrosis of the lateral femoral condyle in a patient with ulcerative colitis: report of a case.

Osteonecrosis is a major complication in patients with ulcerative colitis (UC). It appears most commonly in the femoral head, but sometimes occurs in the proximal humerus or femoral condyle. A 27-year-old Japanese woman presented with severe pain in the left knee in 2006. Osteonecrosis was found in the left lateral femoral condyle, and osteochondral autografting was performed. Ten and a half years prior to this episode, at the age of 17 years, she had been diagnosed as having UC, and after 18 months of medication, she had undergone total colectomy. A total prednisolone dose of 3020 mg had been administered before the operation, but the true pathogenesis-i.e. idiopathic or steroid-associated osteonecrosis-had not been determined at that time. The osteonecrosis occurred long after prednisolone therapy had been discontinued, and the total dose of prednisolone was not considered to be unusually high. In this case, osteochondral autografting was ultimately required for treatment of the osteonecrosis. However, conservative therapy is indicated for early-stage cases and should result in a good course. We report this case to draw attention to this relatively rare complication of UC and to facilitate early detection of similar lesions.