Central somatosensory changes and altered muscle synergies in subjects with anterior cruciate ligament deficiency.
A disturbed proprioception has been described in patients with an anterior cruciate ligament (ACL) deficient knee. The relation to demographic data and to different commonly associated anatomical lesions, as well as to subjective knee function, was prospectively studied in 16 consecutive patients after an acute knee ligament injury. All patients had a complete rupture of the ACL, but variable associated anatomical lesions. The threshold to detect a passive motion, as a measure of their proprioceptive ability, was registered repeatedly during the first year after injury. Four of the patients had consistently severe and persistent deficits at 1, 2 and 8 months. These four individuals had more chondral lesions and a lower subjective rating of their knee function than the remaining patients. In the whole group there were significant correlations between the recorded thresholds and associated chondral lesions, meniscal lesions and the subjective rating of knee function. We found no significant relation between age, gender, activity level, grade of mechanical laxity increase or a medial collateral ligament rupture, and the proprioceptive recordings. Thus, morphological lesions other than a rupture of the ACL seem to contribute to the proprioceptive deficits after a knee ligament injury, and the patients’ ability to detect a passive motion showed a relation to subjective knee function from the time of injury onwards.