The natural history of legg-calve-perthes disease

Abstract

Background Legg-Calve-Perthes disease (LCPD) is uncommon with a reported incidence of 1 per 10,000. The management of LCPD is one of the most controversial areas in pediatric orthopedics. One reason is the lack of a robust outcome to predict the long term disability, which may take decades to be evident. In this paper, the authors tackled this issue and reported the results of two long term case series. The fi rst study investigated the relationship between a residual deformity of the hip joint and the likelihood of development of osteoarthritis (OA) after 40 years follow up. In the second study, using a classifi cation of hip deformities developed in the fi rst study, they identifi ed clinical and radiographic features of the hip during the active phase of the disease that were associated with the development of the classifi ed hip deformity. Methods The fi rst study reviewed 88 patients (99 hips) with a mean age of 40 years (range 30-60 years). No patient had operative intervention. Clinical evaluation of pain, function, and motion of the hip joint, Harris hip score (HHS) and Iowa hip score (IHS) were undertaken. Radiographic assessment included the nature and degree of residual deformity and the extent of osteoarthritis present. The second study consisted of 68 patients (72 hips), all had been seen early in the disease process and followed up to skeletal maturity with regular radiographs. The average age at presentation was 7.5 years (range 3-15 years). All were managed non-operatively. Results Based on the radiographic characteristics at skeletal maturity, hips in both groups were placed into one of fi ve classes. In the fi rst study, it was found that these fi ve classes were good predictors of development of OA and bad outcomes (Table 145.1 ). Classes IV and V were particularly associated with poor outcomes. In the second study, the authors investigated several clinical and radiographic profi les during the active stage of the disease that led to develop each one of the above fi ve classes. Table 145.2 summarises their fi ndings. Conclusions Hips with LCPD could be placed into one of fi ve classes of deformity based on its radiographic appearance at skeletal maturity. Each class showed a characteristic pattern of involvement during the active stages of the disease and had a specifi c long-term clinical and radiographic course. The clinical and radiographic course of an involved hip subsequent to childhood was related to the type of congruency that existed between the femoral head and acetabulum.