Jumper's knee.

Jumper's knee (patellar or quadriceps tendon tendonitis) is found in a high number of athletes, especially in volleyball and basketball players. Conservative treatment (rest, stretching, physical therapy and antiinflammatory drugs) is usually successful. The athletes often recover completely and resume their sports activity. The purpose of this study is to present the histologic findings and our surgical repair of 18 knees of patients who underwent surgery after failure of conservative treatment. Histologic findings confirm that the so-called "jumper's knee" is a pathology localized at the bone-tendon junction. In all cases the following abnormalities were found: pseudocystic cavities at the borderline between mineralized fibrocartilage and bone, disappearance of the "blue line," increased thickness of the insertional fibrocartilage with myxomatous and hyaline metaplasia, mineralization, and ossification of the fibrocartilage far from the "blue line." Abnormalities of the patellar tendon were observed only in one patient who received local injection of corticosteroids. Eleven of the 18 surgically treated knees obtained a satisfactory result with complete resumption of sports activity.