Association of Hip and Foot Factors With Patellar Tendinopathy (Jumper's Knee) in Athletes

Study Design Clinical measurement, cross-sectional. Background Investigations on the causes of patellar tendinopathy (PT) should consider impairments at the hip and foot/ankle since they are known to influence movement patterns and affect patellar tendon loading. Objectives To investigate, by means of CART analysis, impairments of the hip and foot/ankle that are associated with PT in volleyball and basketball athletes. Methods One-hundred and ninety athletes were assessed for impairments of the hip and foot/ankle including: shank-forefoot alignment (SFA), ankle dorsiflexion range of motion (DF ROM), iliotibial band flexibility, passive hip internal rotation (IR) ROM, and hip external rotator (ER) and hip abductor isometric strength. Athletes with tenderness and/or pain at the inferior pole of the patella were considered as having PT. Athletes with VISA-P scores above 95 points, no pain at single-leg decline squat and no history of patellar tendon pain history were considered as not having PT. CART analysis was performed to identify interacting factors associated with PT. Results Interactions among passive hip IR ROM, SFA, hip ER and abductor strength identified athletes with and without PT. The model achieved 71.2% sensitivity and 74.4% specificity. The area under the ROC curve was 0.77 (95% confidence interval: 0.70 - 0.84; p