Relationship Between Mechanoreceptors in the Posterior Cruciate Ligament and Patient Age or Osteoarthritis Severity

Abstract

Background: Mechanoreceptors in the posterior cruciate ligament (PCL) can produce proprioception, which is an important reason why patients choose cruciate-retaining total knee arthroplasty (TKA). The number of mechanoreceptors in the PCL of patients with knee osteoarthritis (OA) is unknown. Purpose: To provide a theoretical basis for estimating the number of mechanoreceptors in the PCL by evaluating the relationship between this number and patient age or OA severity. Study Design: Cross-sectional study; Level of evidence, 3. Methods: An overall 28 PCLs from patients with knee OA were collected at the time of TKA and grouped according to patient age (group A, 60-69 years [n = 8]; group B, 70-79 years [n = 12]; group C, ≥80 years [n = 8]) and OA based on Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score (group I, ≤80 [n = 8]; group II, 81-120 [n = 10]; group III, >120 [n = 10]). Hematoxylin and eosin and S-100 immunohistochemical staining were performed on the slices near the tibial attachment of the PCL, and the number of mechanoreceptors in each slice was counted. Multifactor analysis of variance was used to evaluate the relationship between the number of mechanoreceptors and patient age or WOMAC score. Results: The number of mechanoreceptors (mean ± SD) in groups A, B, and C was 24.00 ± 15.19, 30.92 ± 11.41, and 23.38 ± 11.39, respectively, with no significant between-group differences. The number of mechanoreceptors in groups I, II, and III was 43.50 ± 4.99, 25.00 ± 5.27, and 15.20 ± 5.61, with significant differences between groups I and II, groups I and III, and groups II and III ( P < .001 for all). Conclusion: In patients with knee OA, age had no significant effect on mechanoreceptor count, but the number of mechanoreceptors in the PCL decreased significantly with higher (worse) WOMAC score. These findings suggest that in patients of any age with high WOMAC scores, there may be little value as it relates to knee proprioception in performing a PCL-retaining TKA.

Proprioception and Mechanoreceptors in Osteoarthritis: A Systematic Literature Review

“…Comparable results were also obtained examining a larger cohort of OA patients [34]. Moreover, it was demonstrated that the number of PCL mechanoreceptors decreased with increasing WOMAC score (a measure of knee OA severity) [33]. The presence of neural structures in the PCL resected during posterior stabilized arthroplasty and during primary total knee arthroplasty were found, respectively, in ~67.5% and 77% of OA patients, with the neurovascular bundle being degenerated in 65% of the cases [35,36].…”

“…Several findings were noted in the study. First, there was no observed correlation between the quantification of neural elements and the age of the individuals in the study [33,37]. However, within the OA group, a statistically significant reduction in neural elements was observed in males compared to females.…”

“…Several factors related to knee OA have been hypothesized as possible causal factors for impaired proprioceptive accuracy, particularly mechanoreceptors alterations. Changes in the presence of specific types of mechanoreceptors (Ruffini, Pacini, and Golgi-Mazzoni corpuscles) were evaluated in most studies (9/14) using a combination of immunohistochemistry and histology (S-100, p75, PGP9.5, and hematoxylin-eosin staining) [28][29][30][31][32][33][34][35][36][37][38][39][40][41]. It was found that the numbers of Golgi corpuscles, Ruffini corpuscles, free nerve endings, total nerve endings, and small vessels in the PCL were low in OA patients [28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”

“…Almost all the studies considered both female and male patients, with a higher prevalence of females. Two studies did not specify the sex [32,33]. Except for two studies [29,30] that evaluated the proprioceptive feedback mechanism in the OA carpometacarpal joint, all the other studies analyzed proprioception in the OA knee joint, particularly focusing on…”

“…Almost all the studies considered both female and male patients, with a higher prevalence of females. Two studies did not specify the sex [32,33]. Except for two studies [29,30] that evaluated the proprioceptive feedback mechanism in the OA carpometacarpal joint, all the other studies analyzed proprioception in the OA knee joint, particularly focusing on the posterior cruciate ligaments (PCLs) where the changes and presence of specific types of mechanoreceptors (Ruffini, Pacini, and Golgi-Mazzoni corpuscles) were evaluated.…”