Abstract
Background: Studies assessing proprioceptive acuity in anterior cruciate ligament (ACL)-deficient knees have only considered proprioception for knee movements in the sagittal plane rather than in the transverse plane (ie, rotation), despite the fact that the ACL plays a critical role in knee rotational stability and that the ACL is injured almost exclusively with a rotation mechanism. Therefore a test of proprioception is needed that involves movements similar to the mechanism of injury, in this case, rotation.
Purpose: To determine whether proprioceptive acuity in rotation changes after ACL injury and reconstruction, and to examine differences in proprioceptive acuity, range, laxity, and activity level among injured knees, contralateral knees, and healthy controls.
Design: Cohort study; Level of evidence, 2.
Methods: Proprioceptive acuity for active knee rotation movements, passive rotation range of motion, anterior knee laxity, and knee function were measured in 20 consecutive participants with unilateral ACL rupture and 20 matched controls. Reconstruction was performed using a single-incision technique with a 4-strand hamstring tendon autograft. Thirty participants (15 control and 15 ACL reconstructed) were retested at 3 months, and 14 with ACL reconstruction were tested at 6 months.
Results: A deficit was found in preoperative knee rotation proprioception compared with healthy controls (P = .031). Three months after reconstruction, there was a significant improvement (P = .049) in proprioceptive acuity, single-plane anterior laxity (P = .01), and self-reported knee function (P = .001). At 3 months after reconstruction, proprioceptive acuity of the ACL-reconstructed knee was correlated with reported activity level (r = .63; P = .021).
Conclusion: Knee rotation proprioception is reduced in ACL-deficient participants compared with healthy controls. Three to 6 months after reconstruction, rotation proprioceptive acuity, laxity, and function were improved. While these findings are consistent with a return to previous activity level 6 months after reconstruction, the extent of graft maturation and restoration of kinematics should also inform the decision about return to sport.