Objective
To assess the jumper's knee for the symptoms and diagnostics by MRI and ultrasonography in basket ball players.

Method
Twenty knees of 10 basketball players with chronic knee pain were assessed by the history taking, physical examination and diagnosis by magnetic resonance imaging and ultrasonography. Their average age was 17.4 years. Stanish classification is used for grading the symptoms of jumper's knee.

Results
Nine proximal patellar tendons were diagnosed as jumper's knees (45%) and 11 distal tendons were diagnosed as jumper's knees (55%). In ultrasonographic findings, average proximal patellar tendon thickness was 4.5 mm⁑1.2 mm, and distal patella tendon thickness was 7.1⁑1.1 mm. Sensitivity was 63% (12/19) and specificity was rated as 100% (21/21). By the MRI findings, sensitivity was rated as 32% (6/19) and specificity was rated as 90% (16/21). Study between the patient's clinical severity level by Stanish classification and thickness of patellar tendon showed no significant correlation (＜0.5).

Conclusion
The ultrasonography to be more convenient and easier as a diagnostic method for the jumper's knee than MRI.