Relationship between the patellar height and the disorder of the knee extensor mechanism in immature athletes.

The purposes of this study were to evaluate the outcome of longitudinal research on the patellar height of immature athletes, and to clarify the relationship with disorders of the knee extensor mechanism. The patellar height of 40 young male soccer players (80 knees) was observed with radiographs of the bilateral knee joint for 2 years. The patellar height was measured using the epiphyseal line method. No subject showed patella alta before the occurrence of the disorder. Of the 12 knees in which the disorder occurred during the observation period, 10 knees (83%) had higher patella after the onset of symptoms than before. The patellar height in the painful stage was considered significant compared with the normal group. Although the patellar position in the predisorder stage was relatively high, this state was considered within the normal scope of physiologic variation, such as the growth spurt.