Mechanoreceptors of the ligaments and tendons around the knee

Abstract

Proprioceptive inputs from the joints and limbs arise from mechanoreceptors in the muscles, ligaments and tendons. The knee joint has a wide range of movements, and proper neuroanatomical organization is critical for knee stability. Four ligaments (the anterior (ACL) and posterior (PCL) cruciate ligaments and the medial (MCL) and lateral (LCL) collateral ligaments) and four tendons (the semitendinosus (STT), gracilis (GT), popliteal (PoT), and patellar (PaT) tendons) from eight fresh frozen cadavers were harvested. Each harvested tissue was divided into its bone insertion side and its tendinous part for immunohistochemical examination using S100 staining. Freeman-Wyke's classification was used to identify the mechanoreceptors. The mechanoreceptors were usually located close to the bone insertion. Free nerve endings followed by Ruffini endings were the most common mechanoreceptors overall. No Pacini corpuscles were observed; free nerve endings and Golgi-like endings were most frequent in the PCL (PCL-PaT: P = 0.0.1, PCL-STT: P = 0.00), and Ruffini endings in the popliteal tendon (PoT-PaT: P = 0.00, Pot-STT: P = 0.00, PoT-LCL: P = 0.00, PoT-GT: P = 0.00, PoT-ACL: P = 0.09). The cruciate ligaments had more mechanoreceptors than the medial structures (MS) or the patellar tendon (CR-Pat: P = 0.000, CR-MS: P = 0.01). The differences in mechanoreceptor distributions between the ligaments and tendons could reflect the different roles of these structures in the dynamic coordination of knee motion. Clin. Anat. 29:789-795, 2016. © 2016 Wiley Periodicals, Inc.

Anterior Cruciate Ligament Mechanoreceptors and their Potential Importance in Remnant-Preserving Reconstruction: A Review of Basic Science and Clinical Findings

“…22 Likewise, there is agreement that these receptors are located peripherally (in the subsynovial layer), alongside blood vessels, sitting within interfascicular gaps of the ligament. 16,20,22 Similar MRCs have been found in other structures of the knee including the posterior cruciate ligament (PCL), collateral ligaments, menisci, joint capsule, and skin. 20,[23][24][25] In these structures, the same distribution of MRCs (concentrated around bony attachments) is observed.…”

“…16,20,22 Similar MRCs have been found in other structures of the knee including the posterior cruciate ligament (PCL), collateral ligaments, menisci, joint capsule, and skin. 20,[23][24][25] In these structures, the same distribution of MRCs (concentrated around bony attachments) is observed. 20 The fibers, originating from these MRCs, form a network (alongside those originating from the ACL) resulting in an afferent signal.…”

“…20,[23][24][25] In these structures, the same distribution of MRCs (concentrated around bony attachments) is observed. 20 The fibers, originating from these MRCs, form a network (alongside those originating from the ACL) resulting in an afferent signal. Within the central nervous system, these signals are modulated and a response formed 24 -shown in ►Fig.…”

“…[14][15][16][17][18][19] Many studies have found the distribution of MRCs to be concentrated around the femoral and tibial insertion sites of the ACL. 15,16,[20][21][22] In a study of uninjured knees, Krauspe et al found 15 of 17 MRCs at the attachments leaving only 2 of 17 in the central region of the ligament. 22 There is no clear definition of the proximity of these fibers to the bony attachments and the exact distances are likely relative to specimen size and preparation.…”

Anatomy and Physiology of Knee Stability

“…However, there remains some controversy about the types and precise location of mechanoreceptors in human ligaments [41]. For example, Cabuk and Cabuk [42] examined a small sample of human cadaver ligaments and tendons to determine the presence and distribution of mechanoreceptors. The reported that free nerve endings followed by Ruffini endings and Golgi-like endings were the most prevalent type of mechanoreceptors.…”