Chapter 6 - Epiphyseal Disorders of the Knee: Distal Femur, Proximal Tibia, and Proximal Fibula

Abstract

This chapter discusses the current understanding of the stages, etiology, and pathogenesis of several epiphyseal disorders of knee including osteochondritis dissecans, infantile tibia vara, adolescent tibia vara, and Osgood-Schlatter disease. There are many developmental irregularities in the radiologic appearance of the distal femoral epiphysis, particularly of the secondary ossification center, which are well within a normal range and must not be mistaken for pathological processes. The irregularities include rough or serrated margins of the secondary ossification center, thin bony protuberances from the margins of the secondary center, and small accessory ossification centers. Osteochondritis dissecans is an epiphyseal disorder in which a localized segment of subchondral bone undergoes necrosis and gets demarcated from the surrounding normal bone. When accompanied with fracture and failure of repair it can become separated, along with the overlying articular cartilage, partly or completely from the joint surface, forming an osteocartilaginous loose body or joint mouse. The disorder is seen most commonly in the knee (distal femur), but also in the elbow (capitellum) or ankle (talus), and even more rarely in the proximal humerus and proximal femur.