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" and 60" flexion under non-weightbearing conditions, and at 40" 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 13 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.

Knee joint position sense was assessed by active tests with active limb matching responses in supine lying and in unilateral weightbearing (WB) stance using (re)positioning of the whole limb whilst focusing on the knee, and in supine lying using (re)positioning confined to the knee. Following five tests at approximately 45 degrees knee flexion in all three test conditions, position sense was found to be significantly more accurate and reliable following the WB procedure. Possible explanations are, first, that during WB the subjects were more able to assist identification of the test positions using cues obtained during movement of the knee to and from these positions. Second, a larger volume of proprioceptive afferent information may have been derived from sources outside the examined knee, and even outside the examined limb. Whilst WB joint position sense assessments are more functional, the obtained results may not characterise the capacity of the proprioceptors in and around the examined (knee) joint. Since the WB and NWB results were not correlated, one procedure cannot be used to predict results from the others. Also, predominantly unilateral WB stance is often impractical for subjects with limited balance or WB pain.

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Purpose. The ability to sense the position of limb segments is a highly specialised proprioceptive function important for control of movement. Abnormal knee proprioception has been found in association with several musculoskeletal pathologies but whether nociceptive stimulation can produce these proprioceptive changes is unclear. This study evaluated the effect of experimentally induced knee pain on knee joint position sense (JPS) in healthy individuals.Study design. Repeated measures, within-subject design.Metlzods. Knee JPS was tested in 16 individuals with no history of knee pathology under three experimental conditions: baseline control, a distraction task and knee pain induced by injection of hypertonic saline into the infrapatellar fat pad. Knee JPS was measured using active ipsilateral limb matching responses at 20" and 60" flexion whilst non-weightbearing (NWB) and 20" flexion single leg stance. During the tasks, the subjective perception of distraction and severity of pain were measured using 1 I-point numerical rating scales.Results. Knee JPS was not altered by acute knee pain in any of the positions tested. The distraction task resulted in poorer concentration, greater JPS absolute errors at 20" NWB, and greater variability in errors during the WB tests. There were no significant correlations between levels of pain and changes in JPS errors. Changes in JPS with pain and distraction were inversely related to baseline knee JPS variable error in all test positions (v = -0.56 to -0.91) but less related to baseline absolute error. Cotwlu.rion. Knee JPS is reduced by an attention-demanding task but not by experimentally induced pain.

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