Clinical Measures and Their Contribution to Dysfunction in Individuals With Patellar Tendinopathy

Context: Patellar tendinopathy (PT) is prevalent in physically active populations, and it affects their quality of living, performance of activity, and may contribute to the early cessation of their athletic careers. A number of previous studies have identified contributing factors for PT; however, their contributions to self-reported dysfunction remain unclear.

Objective: The purpose of this investigation was to determine if strength, flexibility, and various lower-extremity static alignments contributed to self-reported function and influence the severity of PT.

Design: Cross-sectional research design.

Setting: University laboratory.

Participants: A total of 30 participants with PT volunteered for this study (age: 23.4 [3.6] y, height: 1.8 [0.1] m, mass: 80.0 [20.3] kg, body mass index: 25.7 [4.3]).

Main outcome measures: Participants completed 7 different patient-reported outcomes. Isometric knee extension and flexion strength, hamstring flexibility and alignment measures of rearfoot angle, navicular drop, tibial torsion, q-angle, genu recurvatum, pelvic tilt, and leg length differences were assessed. Pearson's correlation coefficients were assessed to determine significantly correlated outcome variables with each of the patient-reported outcomes. The factors with the highest correlations were used to identify factors that contribute the most to pain and dysfunction using backward selection, linear regression models.

Results: Correlation analysis found significant relationships between questionnaires and body mass index (r = -.35-.46), normalized knee extension (r = .38-.50) and flexion strength (r = -.34-.50), flexibility (r = .32-.38, q-angle (r = .38-.56), and pelvic tilt (r = -.40). Regression models (R² = .22-.54) identified thigh musculature strength and supine q-angle to have greatest predictability for severity in patient-reported outcomes.

Conclusions: These findings put an emphasis of bodyweight management, improving knee extensor and flexor strength, and posterior flexibility in PT patients.