Effect of Lateral Ankle Joint Anesthesia on Center of Balance, Postural Sway, and Joint Position Sense

The purpose of this study was to investigate the effects of induced anesthesia of the lateral ankle joint on proprioception as assessed in weight-bearing and non-weight-bearing conditions. Sixteen subjects were assessed under normal conditions and following an 8-cc injection of lidocaine into the anterior talofibular ligament of the ankle being tested. Center of balance and postural sway measurements were analyzed, revealing a significant lateral adjustment of center of balance during the stable tests compared to a medial adjustment during the dynamic tests under the anesthetized condition. ANOVA of postural sway scores revealed no main effect for condition (anesthesia vs. no anesthesia), but sway scores were higher during the two dynamic conditions as compared to the stable condition. ANOVA of joint position error scores revealed no main effect for condition. Findings suggest that inhibition of the joint receptor afferent fibers adversely affected joint proprioception as assessed while subjects were weight bearing but not while they were non-weight bearing.