Proprioception in poor- and well-functioning anterior cruciate ligament deficient patients

The aim of this study was to examine proprioception with and without muscle tension and knee function in two groups of chronic (> 1 year post-injury) patients with deficient anterior cruciate ligaments with distinctly different functioning levels. The well (WF) and poor functioning (PF) group was defined as those with a Tegner/Lysholm score equal to or greater than 6/95 (WF, n = 7), and equal to or less than 4/83 (PF, n = 7), respectively. Clinical examination included a Lachman, and a Pivot shift test, as well as a KT2000 arthrometer assessment. Single and triple hop tests assessed one-legged performance. Proprioception was measured as threshold of passive movement detection, and as the ability to reproduce flexion angles with (20% and 50% MVC) and without muscle tension. Mean Tegner/Lysholm scores were: WF: 7 (range 6-8)/98 (range 95-100), PF: 2 (range 1-4)/71 (range 62-80). There were significant differences between the Pivot shift tests of the groups (p = 0.01). The laxity (KT2000) assessment yielded a significant (3 mm, p < 0.05) side-to-side difference in both groups. One-leg hop tests yielded no side-to-side differences in any of the groups or between the groups. There were no significant differences between the groups in any of the proprioceptive tests, except in one of the angle reproduction tests with muscle tension (20%, p < 0.05). WF had larger mean errors than PF. There was not found any side-to-side difference in any of the proprioceptive tests, except in one of the angle reproduction tests with muscle tension (WF, 20%, p < 0.05). In conclusion, these data suggest that subjects with long standing anterior cruciate ligament deficiency in the present study did not have a knee joint proprioceptive deficit as measured by some commonly accepted methods. There was no difference in proprioception between the two groups despite their markedly different function levels and pivot shift evaluated knee laxity.