The effects of two different closed kinetic chain exercises on muscle strength and proprioception in patients with patellofemoral pain syndrome

Objectives: The effects of two different closed kinetic chain exercises were compared in patients with patellofemoral pain syndrome (PFPS). Methods: Forty female patients with unilateral PFPS were randomly divided into two groups to receive exercises with the hip internally rotated (n=20, mean age 39.1 +/- 8.0 years) or externally rotated (n=20, mean age 36.1 +/- 8.7 years) with the use of the Monitored Rehab Functional Squat (MRFS) System. The duration of exercises was four weeks with a total of 20 sessions. Both groups were evaluated before therapy, after four weeks of exercises, and after six weeks of home exercise program with the MRFS System for muscle strength and proprioception, with a visual analog scale for pain, and with the Kujala questionnaire for functional assessment. Results: Among baseline features, the only significant difference between the two groups was in the mean height (p<0.05). Pain severity decreased significantly in both groups after treatment and home exercises (p<0.05). Concentric and eccentric peak forces, concentric proprioceptive deficit, and Kujala scores improved significantly in both groups after treatment (p<0.05), whereas improvements after home exercises were not significant in this respect (p>0.05). Eccentric proprioceptive deficit, however, did not change significantly both after treatment and home exercises (p>0.05). No significant differences were observed between the two groups during the study period with respect to the parameters assessed (p>0.05). Conclusion: Our results show that functional knee squat exercises with internally and externally rotated hip positions provide similar improvements in muscle strength and proprioception in patients with PFPS.