LIGAMENT-MUSCLE REFLEX ARC AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION - ELECTROMYOGRAPHIC EVALUATION

The purpose of this study was to determine if a ligament-muscle reflex are exists between the bone-patellar tendon-bone autograft after ante rior cruciate ligament (ACL) reconstruction and the hamstring muscle g roup. We studied four patients, average age 34.2 years (range 32-36 ye ars). The mean time between the ACL reconstruction and the study exami nation was 56.2 months (range 5-108 months). All patients underwent a second-look arthroscopy for meniscal injuries, cyclops lesions, or adh esions. Five patients with a normal ACL served as a control group befo re we performed an arthroscopic meniscectomy. Electromyographic (EMG) activity was measured using fine wire electrodes under two different t esting conditions. No unequivocal EMG activity could be detected in th e ACL-reconstructed knees when we pulled on the graft or in the contro ls. Three of four patients and all controls felt pain when we touched the graft or normal ACL or applied strain on it with the hook. In conc lusion, the ACL autograft presents a noxious sensory innervation, the Lachman test maneuver stimulates a reflex are with hamstrings activati on, and an unequivocal ligament-muscle reflex are from the graft tu th e hamstring muscle group could not be demonstrated.