Reliability of knee functional tests in patients with patellofemoral pain syndrome

Document Type : Original Articles


1 MSc in sport injury and corrective exercise, faculty of physical education and sport science, university of Tehran, Tehran, Iran.

2 MSc Students of Education and Sport Science, Islamic Azad University of Tehran, Markaz Branch, Tehran, Iran.



Abstract   Introduction: Patellofemoral pain syndrome (PFPS) is a common clinical term used to describe a variety of pathologic conditions related to the articulation between the patella and the femoral condyles. The aim of this study was to evaluate the reliability of knee performance tests in patients with Patellofemoral pain syndrome. Materials and Methods: 15 subjects with patellofemoral pain syndrome and 17 subjects without any pain in patellofemoral joint participated in this study. The Single-Leg Press, Step-down, Bilateral Squat and Antromedial Lung were the tests whose reliability was examined in the present study. For statistical analysis of data, the Pearson correlation coefficient, paired t-test and Interclass Correlation Coefficient (ICC) tests were used (α ≤ 0.05). Results: The reliability of 4 functional performance tests used in this study ranged from 0.79 to 0.94. With the exception of the Squat test, there was significant differences in number of test repetitions in the group with patellofemoral pain (P = 0.01). All functional performance tests correlated significantly with pain except the Squat test. Limb Symmetry Index (LSI) was 80% for the group with patellofemoral pain and 97% for the control group. The reliability between the four above-mentioned functional tests was high and it had a positive correlation with changes in pain. Conclusion: since the functional tests used in the present study proved to have high reliability, it is suggested that these tests be applied for evaluating patients with patellofemoral pain syndrome. Keywords: Reliability, Knee, Patellofemoral pain syndrome.