PATELLAR TENDINOSIS (JUMPERS KNEE) - FINDINGS AT HISTOPATHOLOGIC EXAMINATION, US, AND MR-IMAGING

PURPOSE: To determine the histopathologic findings of patellar tendino sis (''jumper's knee'') demonstrated with ultrasonography (US) and mag netic resonance (MR) imaging. MATERIALS AND METHODS: Twenty-four athle tes (28 knees) with jumper's knee (23 men, one woman; mean age, 30.9 y ears) scheduled to undergo open tenotomy underwent US patellar tendon examination. Seventeen patients (19 knees) also underwent MR imaging. Tissue was obtained for histopathologic examination in all 28 cases. E leven age-, height-, and weight-matched athletes (22 knees) without pr evious knee symptoms served as control subjects for the US examination . Control material for histopathologic examination was obtained in 20 cadavers (39 knees). Data were analyzed with standard statistical meth ods. RESULTS: MR imaging and US both revealed an abnormal zone at the proximal patellar tendon attachment. Histopathologic examination revea led mucoid degeneration in all tendons in patients and in 8% (three of 39) of tendons in cadavers (P < .01). CONCLUSION: Jumper's knee is ch aracterized by consistent changes at MR imaging, US, and histopatholog ic examination and is appropriately described as patellar tendinosis.