ACL Pacinian mechanoreceptors: Conceptualizing a vasoregulatory microtrauma healing function

Abstract

Purpose: Improved understanding of important natural anterior cruciate ligament (ACL) tissue functions may strengthen the case for their preservation. This commentary revisits human and comparative animal research studies of Pacinian mechanoreceptor histology, morphology and function, including those near the native proximal ACL and relates these findings to accumulated microtrauma healing and graft remodelling. Methods: Using the PubMed, Google Scholar and Web of Science databases, the medical literature was searched for peer-reviewed information related to ACL morphology, knee joint circulation, ligament neuropeptides and vasoregulation, autonomic nervous system vasoregulation, Pacinian mechanoreceptors, ACL remodelling and nutrition, and psychological stressors and vasoregulation. Information from these searches was then synthesized into a conceptualization of a possible Pacinian mechanoreceptor role in primary ACL microtrauma healing and post-surgical repair or reconstruction tissue remodelling. Results: In association with autonomic nervous system function, Pacinian mechanoreceptors in the ACL may serve an important vasoregulatory function in addition to proprioception. Conclusion: Pacinian mechanoreceptor-mediated vasoregulation may be important for post-sport performance or exercise training during primary ACL healing from accumulated microtrauma. Proximal remnant preservation during ACL reconstruction or repair may facilitate the angiogenic and neurogenic processes that drive native tissue and graft remodelling. Experimental and clinical studies are needed to confirm these concepts. Level of Evidence: Level V.