RESPONSES OF MECHANORECEPTOR NEURONS IN THE CAT KNEE-JOINT CAPSULE BEFORE AND AFTER ANTERIOR CRUCIATE LIGAMENT TRANSECTION

It is known that afferent neurons play a protective role in knees made unstable by transection of the anterior cruciate ligament. However, i t is not known whether cutting the anterior cruciate ligament has an e ffect on the response of the sensory neurons that innervate the joint. In this study, the responsiveness (activation threshold and position sensitivity) of single, mechanically sensitive afferent neurons from t he cat knee was evaluated by a series of extension, internal, and exte rnal rotations. The anterior cruciate ligament then was cut and the sa me procedure was repeated. Transection of the ligament increased joint laxity for all types of rotations. The responsiveness of the neurons was not changed significantly by cutting the ligament (p > 0.05). Ther efore, capsule afferents continue to behave normally in joints in whic h the anterior cruciate ligament has been transected.