Orthopedic & Muscular System: Current Research
Open Access

Anterior Cruciate Ligament Innovations

The ACL receives nerve fibers from the posterior articular branches of the tibial nerve.  These fibers penetrate the posterior joint capsule and run along with the synovial and periligamentous vessels surrounding the ligament to reach as far anterior to the infrapatellar fat padMost of the fibers are associated with the endoligamentous vasculature and have a vasomotor function. The receptors he mechanoreceptors cited above (Ruffini, Pacini, and Golgi-like receptors) have a proprioceptive function and provide the afferent arc for signaling knee postural changes. Deformations within the ligament influence the output of muscle spindles through the fusimotor system.  Hence, activation of afferent nerve fibers in the proximal part of the ACL influences motor activity in the muscles around the knee; a phenomenon called ‘‘ACL reflex.’’ These muscular responses are elicited by stimulation of group II or III fibers (i.e. mechanoreceptors). The ACL reflex is an essential part of normal knee function and is involved in the updating of muscle programs.  This becomes even more obvious in patients with a ruptured ACL, where the loss of feedback from mechanoreceptors in the ACL leads to quadriceps