An important concept in patellofemoral joint function is the quadriceps angle (Q angle), but there is a standardization problem with the measurement method. The aim of the study was to compare the change of the Q angle in relaxed or maximum voluntary contraction (MVC) of the quadriceps using a standardized measurement method in patients with patellofemoral pain syndrome (PFPS). This cross-sectional analytical study includes 34 sedentary female patients aged 18-50 years with a diagnosis of PFPS. Measurements were carried out with a manual extendable fixed-arm goniometer. For the first measurement, the patient was placed in quadriceps relaxed in supine position. Lower extremity rotation was neutralized using the axial rotation neutralizing apparatus (ARNA). For the second measurement, while the quadriceps was maximally contracted in the same position the midpoint of the patella was re-marked and then the measurement was repeated. The Q angle measurements taken in quadriceps relaxed and MVC were 18.44° ± 2.80° and 16.41° ± 2.83°, respectively (p = .00). It was determined that there was no correlation between age, height, weight, body mass index (BMI), leg length and Q angle measurements of the participants (p > .05). In conclusion, this measurement method offered measurement estimations that verified the effect of the quadriceps on the Q angle in patients with PFPS. The prevention of axial rotation in the leg and the use of an extendable fixed-arm goniometer contribute to the standardization of Q angle measurement.
ARNA, PFPS, Q angle, quadriceps