The knowledge of distribution of nociceptive and proprioceptive nerve fibers in cruciatre ligaments in human knee joint would provide insight in understanding the sensory role of cruciate ligaments. The ligaments have been mainly considered as
mechanical and structural joint stabilizer. However, ligaments and other joint structures may serve as more refined sensors.
The innervation of 24 human anterior and posterior cruciate ligaments obtained during total knee arthroplasty, mainly total knee arthroplasty, was studied. Immunocytochemical technique using monoclonal antibody to substance P (SP),
leucine-enkephalin
(leu-Enk), neurofilament (NF) 200 and glial fibrillary acidic protein (GFAP) and acetylcholinesterase (AChE) histochemistry were employed to identify sensory nerve fibers.
The nerve fibers and nerve endings were found in synovium, fat pad and intrafascicular connective tissue of cruciate ligaments. The nerve fiber was myelinated showing GFAP-immunoreactive and/or unmyelinated showing GFAP-nonreactive. The nerve
fiber
was
immnogreactive to SP, leu-Enk and NF 200 and had terminal nerve strctures with free nerve endings providing nociception and supplying blood vessels, Ruffini corpuscles and Facinian corpuscles. Both of the corpuscles were known to be
mechanoreceptors.
These three kind of nerve endings were observed in all cruciate ligaments and distributed denser in both end of cruciate ligaments. AChE-positive nerve fibers and Ruffini corpuscles were observed, more common in posterior cruciate ligament than
anterior. In intrafascicular space of cruciate ligamjent, Pacinian corpuscles was noted, but other two nerve endings not. Golgi organ wasnot found in every cruciate ligament.
The presence of nociceptive receptors and nerve fibers in the anterior and posterior cruciate ligaments were confirmed by a immunocytochemical method using monoclonal antibody for SP, leu-Enk, NF 200 and GFAP and AChE histochemistry.
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