Intrinsic risk factors for the development of patellar tendinitis in an athletic population - A two-year prospective study

Retrospective studies have suggested various factors that might cause a dis position to develop patellar tendinitis, but no prospective data exist to d etermine any relationships. The purpose of this study was to determine the intrinsic risk factors for the development of patellar tendinitis in an ath letic population. Before the study, 138 male and female students of physica l education were evaluated for anthropometric variables, leg alignment char acteristics, and muscle tightness and strength parameters. During the 2-yea r study, 19 of the 138 students developed patellar tendinitis. In all cases the diagnosis was confirmed by the presence of a hypoechogenic nodular les ion in the proximal region of the patellar tendon. Univariate and stepwise discriminant function analyses were performed comparing the various measure ments. These analyses revealed that the only significant determining factor was muscular flexibility, with the patellar tendinitis patients being less flexible in the quadriceps and hamstring muscles (P < 0.05). The results o f this study demonstrate that lower flexibility of the quadriceps and hamst ring muscles may contribute to the development of patellar tendinitis in an athletic population. Therefore, the prevention of this condition in athlet es should be focused on screening for and treating poor quadriceps and hams tring muscle flexibility.