Residual hip deformities secondary to Legg-Calvé-Perthes disease (LCPD) include growth disturbance of the proximal femoral physis with nonspherical femoral head, overriding greater trochanter with short femoral neck and secondary remodeling of the acetabulum. These deformities can change the mechanical function of the hip joint and contribute to femoroacetabular impingement. All these deformities need to be recognized and its contribution to the patient's symptoms understood before a treatment strategy can be planned. Safe surgical dislocation of the hip allows for complete inspection of the hip joint and dynamic assessment of femoroacetabular contact during hip motion. The goals of this paper are to review the pathophysiology, clinical presentation, imaging findings, and the management of femoroacetabular impingement in patients with LCPD. We sought to present our treatment philosophy for patients who were diagnosed and treated for LCPD as a child and present with femoroacetabular impingement as adolescents and young adults.