Multifocal osteonecrosis related to corticosteroid: ten years later, risk of progression and observation of subsequent new osteonecroses.

PURPOSE: No study has reported the risk of other site osteonecroses after the diagnosis of multifocal osteonecrosis related to corticosteroids in patients who continue this corticosteroid treatment. An analysis of the time-course to other sites of osteonecrosis, as well as the effects of underlying corticosteroid risk factor on the evolution of asymptomatic lesions at the time of diagnosis, is presented.
METHODS: Two hundred patients were followed prospectively every year during a minimum ten years with a radiograph if a joint became symptomatic. In absence of evidence of osteonecrosis on radiographs of a symptomatic or non-symptomatic joint (hips, shoulders, knees, ankles), patients had an MRI performed at the most recent follow up. The average duration of follow-up after inclusion of the patient in the study was 15 years (range 10-20).
RESULTS: Of the 200 patients followed for an average of 15 years (minimum 10 years, maximum 20 years), 35 patients developed new osteonecrosis lesions during the period of study. Asymptomatic lesions became symptomatic and a high number of collapse was observed resulting in 258 arthroplasties (187 hips, 51 shoulders, 20 knees) at the most recent follow up.
CONCLUSION: The continuation of peak doses (>200 mg) of corticosteroids predicted (p = 0.04) occurrence of new lesions and the continuation of corticosteroids without peak dose was a risk for quicker progression to collapse.