Abnormal knee joint position sense in individuals with patellofemoral pain syndrome.
The purpose of this cross-sectional study was to compare knee joint position sense (JPS) in 20 individuals with and 20 without patellofemoral pain syndrome (PFPS). Five active tests with ipsilateral limb matching responses were performed at 20 degrees and 60 degrees flexion under non-weightbearing conditions, and at 40 degrees flexion under uni- and bi-lateral weightbearing conditions. The response errors were calculated as the difference between each target and response position (accuracy) and the standard deviation of these differences (reliability). JPS was: (i) significantly less accurate and less consistent in the knees with PFPS during both the non-weightbearing and weightbearing tests when compared to the control subject knees; (ii) less accurate when the symptomatic and asymptomatic knees of the 12 uni-lateral PFPS subjects were compared and (iii) less accurate in the asymptomatic knees of the uni-lateral PFPS subjects and knees of the control subjects. The maximum intensity of pain experienced during each knee JPS test was not correlated to any of the JPS test results. The results confirm abnormal knee joint proprioception in individuals with PFPS. Although it cannot be determined whether the abnormality precedes or follows the development of PFPS, the results support including proprioceptive reeducation in management of PFPS.