Knee joint proprioception in ACL-deficient knees is related to cartilage injury, laxity and age: a retrospective study of 54 patients.

BACKGROUND ACL-deficient patients have been found to have proprioceptive defects, but the cause of these defects has not been identified nor has the relationship between proprioception and subjective function, laxity, activity level and age been adequately studied. PATIENTS AND METHODS Therefore, we analyzed proprioception, defined as the threshold to detect a slow passive motion (TTDPM), in relation to activity level, laxity, meniscal injuries, collateral ligament injuries, cartilage injuries, age and subjective function in 54 patients with a previous ACL rupture. We used multiple pair-wise correlation analyses, followed by a stepwise linear regression model. RESULTS We found that poorer proprioception was related to lateral cartilage lesions, increased laxity and older age while a high activity level before injury was related with better proprioception after injury. The results also suggest a relation between proprioception and subjective knee function. INTERPRETATION Anatomical injuy classification may need to be considered when discussing proprioceptive ability in patients with an ACL injury, laxity is related to proprioception and proprioception may decrease with age.