Effects of knee bracing on the sensorimotor function of subjects with anterior cruciate ligament reconstruction

The sensorimotor performance of the knee joint in 31 subjects who had under gone unilateral anterior cruck ate ligament reconstruction at least 5 month s previously was tested under three bracing conditions, 1) the DonJoy Legen d brace, 2) a mechanical placebo brace, and 3) no brace, in random order. T he accuracy of the subjects' ability to reproduce specified knee joint angl es was tested as well as the isokinetic performance of their knee muscles a t 60 and 180 deg/sec. The results showed that subjects with the brace or pl acebo brace performed similarly in reproducing the knee joint positions, bu t both groups performed better than the subjects without a brace. Isokineti c tests revealed no difference among the three groups in extensor and flexo r peak torque production at 60 deg/sec or total work done by the extensors and flexors at 60 and 180 deg/sec. These results suggest that knee bracing can improve the static proprioception of the knee joint, but not the muscle contractile function, in subjects with anterior cruciate ligament reconstr uction under isokinetic testing conditions. The finding of similar performa nces for joint angle reproduction in the brace and placebo brace groups sug gests that the apparent improvement in proprioception with knee bracing was not due to the mechanical restraining action of the brace.