Late metachronous involvement of the contralateral hip in Legg-Calve-Perthes disease

Bilateral hip involvement in Legg-Calve-Perthes disease occurs in similar t o 10-13% of cases. Although both synchronous and metachronous involvement o f the two hips have been described, metachronous involvement is rare and ge nerally occurs within 6 months to 4 years of initial diagnosis. We report t he cases of two patients diagnosed with late metachronous involvement of th e contralateral hip 8.5 and 9.8 years after initial presentation. This is l ater than previously reported metachronous involvement in Legg-Calve-Perthe s disease and emphasizes, that patients with Leg-Calve-Perthes disease may be at prolonged risk for recurrent disease.