Clinical significance of altered gastrocnemius muscle coordination in anterior cruciate ligament-deficient knees

Abstract

In a study of conservatively treated patients with isolated anterior cruciate ligament (ACL) ruptures, 7 patients with good or excellent results (Lysholm score > 84) and 7 patients with poor results (Lysholm score < 64) were compared considering muscle coordination, which was assessed by means of electromyographic (EMG) recordings from the thigh muscles and the medial head of gastrocnemius and heel contact recordings while the patient walked on a treadmill at different gradients. The results of this study revealed that significant differences were seen only in the medial gastrocnemius. An earlier onset, an earlier peak, a longer activation of EMG and a greater normalized root mean square amplitude, correlating with muscular tension, were seen in the medial gastrocnemius of the patients with good or excellent Lysholm score. This study is the first to investigate and demonstrate EMG differences between ACL-deficient patients with good and poor functional results. Furthermore, it reveals that the strength and coordination of the gastrocnemius might be of importance and should be considered in the search for optimal training programmes.