Background Perthes disease most commonly affects children 5 to 7 years old, and nonoperative management, such as weightbearing and activity restrictions, is generally recommended. In earlier research in children aged 8 to 14 years who had Perthes disease, we found that the restrictions were associated with worse mobility, but mental health or social health measures were not linked. However, Perthes disease most commonly affects children 5 to 7 years old who are more emotionally and cognitively immature. Children in this age group are beginning school and organized sports experiences while developing meaningful social relationships for the first time. Because of such different life experiences, it is important to One author (HKWK) holds a patent for an osteonecrosis treatment device. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request.