Proprioceptive acuity in patients with a torn anterior cruciate ligament following a rehabilitation programme

Introduction: Rupture of the Anterior Cruciate ligament (ACL) results in instability of theknee and repeated episodes of "giving away", where the knee fails under conditions ofrotary stress. This instability has been attributed to poor proprioception, which in turn hasbeen credited to disruption of the mechanoreceptors. Although several studies show thatproprioception is improved by neuromuscular training, most studies use the contra-laterallimb as a control, which raises the question of whether there may be a pre-disposingproprioceptive deficit leading to injury.Aims: To investigate the effect of rehabilitation of ACL deficient (ACLD) patients on avariety of tests that measure proprioceptive acuity.Methods: Subjects (N=18, mean age 34.5yrs) diagnosed with ACLD, were tested forproprioceptive acuity prior to, and after 6- and 12-weeks of rehabilitation. Joint positionsense (JPS) using a reproduction of limb position, single leg static balance (postural sway)using a stable force platform, and dynamic balance using the Star Excursion Balance(SEBT) test were used as measures of proprioceptive acuity.Results: Results show that there are significant differences in proprioception betweeninjured and non-injured limbs in terms of JPS and the SEBT although this was not inmeasurement of postural sway. Furthermore these observed differences remained even after12-weeks rehabilitation. There was a significant difference in the frontal planemeasurements of SEBT between the uninjured contra-lateral limbs when compared to agroup of normal knees of uninjured subjects.Conclusions: It appears that JPS and dynamic balance is significantly affected by injury tothe ACL; however, the results suggest that some aspects of proprioception (posturalcontrol) may well be a predisposing factor to ACL injury, whilst other aspects such as jointposition sense, occur as a result of injury. A 12-week rehabilitation period does not appearto significantly improve proprioceptive acuity