Inflammatory bowel disease related osteonecrosis: report of a large series with a review of the literature.

BACKGROUND: Osteonecrosis is a major complication of inflammatory bowel disease usually associated with steroid use. There are few large series available detailing the specifics of affected patients. AIM: To identify any specific characteristics of osteonecrosis in this cohort. A major focus was placed on steroid dose, the average time between diagnosis of IBD and appearance of osteonecrosis and the frequency of multiple joint involvement.
METHODS: Our study identified 23 patients in the practices of five gastroenterologists at the Mount Sinai Medical Center. We retrospectively reviewed their clinical history, as well as imaging studies. We classified osteonecrosis according to the Association Research Circulation Osseous (ARCO) staging system.
RESULTS: Although our prednisone dosing data could not be used as an accurate predictor of onset or joint distribution, there was a tendency for correlation between the average daily dosing and the ARCO score. The ARCO scoring system was consistent for patients with bilateral hip involvement. The distribution of affected joints in IBD is similar to other conditions associated with osteonecrosis, with hips being the most frequently involved joints. Data showed bilateral involvement in most hips, but usually unilateral disease in the shoulders and knees. Treatment options include core decompression for early stages, whereas joint replacement surgery is required for stages 3 and 4.
CONCLUSION: IBD predisposes patients to corticosteroid induced osteonecrosis. An exact threshold dose has not been determined. The data suggests that either long term therapy or short term high dose treatment increases the risk of osteonecrosis. Even if symptoms are limited to one joint, multiple joints are often involved and comprehensive testing with MRI is indicated in all cases.