Proprioception of the knee joint in patellofemoral pain syndrome

Objectives: The importance of proprioception in the etiol¬ogy, treatment, and prevention of sports injuries and joint diseases has become increasingly clear. The purpose of this study was to investigate knee proprioception in pa¬tients with patellofemoral pain syndrome (PFPS). Methods: The study included 28 patients (18 females, 10 males; mean age 28 years; range 16 to 48 years) with a clini¬cal diagnosis of unilateral PFPS and 27 normal volunteers (13 females, 14 males; mean age 26 years; range 19 to 32 years) without any complaint related to the knee. The mean duration of complaints was 35.8 weeks (range 2 weeks to 3 years). In both patient and control groups, proprioception of the knee was measured by means of active joint position sense at four different target angles (15°, 30°, 45°, 60°) with the use of a digital goniometer and the results were compared. Results: Proprioceptive errors were greater at all target angles in the affected knees compared to those measured in the con- tralateral knees and both knees of the controls. Differences between affected knees and contralateral knees ranged from 1.01±0.25° to 1.65±0.43° and were significant at three target angles (15°, 30°, 60°; p<0.05). Comparisons between the af¬fected knees and both knees of the controls also showed signifi¬cant differences at all target angles ranging from 2.48±0.92° to 3.87±2.46° (p<0.001). Errors obtained in the normal knees of the patients were also significantly greater compared to those seen in both knees of the controls, exceeding 2.7° at some tar¬get angles (p<0.001). Conclusion: Our results show that patients with PFPS have impaired proprioception in the affected knee accom¬panied by significant losses in the proprioception of the contralateral normal knee. Based on these findings, propri¬oceptive rehabilitation techniques should be incorporated into the treatment of PFPS.