THE RELATIONSHIP BETWEEN QUADRICEPS ANGLE AND ANTERIOR KNEE PAIN SYNDROME

Anterior knee pain syndrome (AKPS) represents a significant challenge for patients and for clinicians. The purposes of this study were: 1) to determine the reliability of the Q-angle measurement, 2) to quantify Q-angle changes that occur with knee flexion, and 3) to determine if subjects with AKPS (N = 52) have a significantly different Q-angle than subjects without AKPS (N = 50). With the knee in an extended position, intratester Q-angle intraclass correlation coefficients (ICC) ranged from .84 to.90, and standard error of measurement (SEM) values ranged from 2.01 to 2.23-degrees. Intertester Q-angle ICC was .83, and the SEM was 2.49-degrees. With the knee flexed, the intratester ICC was .83 for both testers, and SEM values ranged from 0.68 to 2.45-degrees. Intertester ICC and SEM were .65 and 3.50-degrees, respectively. No significant difference was found in intratester Q-angle values be-tween the extended and flexed knee positions (p > 0.05). No significant difference in Q-angle was found between asymptomatic subjects (11.1 +/- 5.5-degrees) and symptomatic subjects (12.4 +/- 5.1-degrees) (p = 0.07). Increased Q-angles were not responsible for AKPS in this group of patients. Other factors were hypothesized to be responsible for their symptoms.