Ultrastructure and Innervation of Thumb Carpometacarpal Ligaments in Surgical Patients With Osteoarthritis

Abstract

Background The complex configuration of the thumb carpometacarpal (CMC-1) joint relies on musculotendinous and ligamentous support for precise circumduction. Ligament innervation contributes to joint stability and proprioception. Evidence suggests abnormal ligament innervation is associated with osteoarthritis (OA) in large joints; however, little is known about CMC-1 ligament innervation characteristics in patients with OA. We studied the dorsal radial ligament (DRL) and the anterior oblique ligament (AOL), ligaments with a reported divergent presence of mechanoreceptors in nonosteoarthritic joints. Questions/purposes This study's purposes were (1) to examine the ultrastructural architecture of CMC-1 ligaments in surgical patients with OA; (2) to describe innervation, specifically looking at mechanoreceptors, of these ligaments using immunohistochemical techniques and compare the AOL and DRL in terms of innervation; and (3) to determine whether there is a correlation between age and mechanoreceptor density. Methods The AOL and DRL were harvested from 11 patients with OA during trapeziectomy (10 women, one man; mean age, 67 years). The 22 ligaments were sectioned in paraffin and analyzed using immunoflourescent triple staining microscopy. Results In contrast to the organized collagen bundles of the DRL, the AOL appeared to be composed of disorganized connective tissue with few collagen fibers and little innervation. Mechanoreceptors were identified in CMC-1 ligaments of all patients with OA. The DRL was significantly more innervated than the AOL. There was no significant correlation between innervation of the DRL and AOL and patient age. Conclusions The dense collagen structure and rich innervation of the DRL in patients with OA suggest that the DRL has an important proprioceptive and stabilizing role. Clinical Relevance Ligament innervation may correlate with proprioceptive and neuromuscular changes in OA pathophysiology and consequently support further investigation of innervation in disease prevention and treatment strategies.

The 2014 ABJS Nicolas Andry Award: The Puzzle of the Thumb: Mobility, Stability, and Demands in Opposition

“…5A-F) and thin volarly (Fig. 6A-D), both as measured in thickness and cellular content [45,62,65,75,109]. We have verified their presence from outside-in with gross dissection, and from inside-out with arthroscopic evaluation (Fig.…”

“…Since the volar ligaments in our studies were deemed insufficient to provide static stability, we believe the thenar muscles, intimal to the volar capsule, are of primary importance in volar CMC joint stability. A followup study we performed examining the ligaments of 11 arthritic subjects at time of surgery (10 women, one man) confirmed the predominance of mechanoreceptors in the dorsal radial ligament and paucity in the anterior oblique ligament [75]. These subjects underwent surgery for symptomatic arthritis and thus may have altered neural and ligament structure compared to asymptomatic individuals; the causal relationship of symptoms, ligament pathology, and mechanoreceptors remains unclear.…”

Hand osteoarthritis: clinical phenotypes, molecular mechanisms and disease management

“…Notable associations between self-reported pain and function have been reported for these patients. Furthermore, compared with healthy individuals, patients with this condition have reduced grip and pinch strength 32 , including a decrease in cylindrical grasp and key pinch strength that can begin in the early stages of disease 33,34 . Some of these presentations might be due to changes in the structure and composition of the joint and changes in the innervation of the dorsal radial ligament, which has an important proprioceptive and stabilising role for the thumb base 35 .…”

Immunohistochemical Mapping of Sensory Nerve Endings in the Human Triangular Fibrocartilage Complex

“…Unclassifiable corpuscles were the second most common mechanoreceptor type, suggesting a high morphologic variety of sensory nerve endings, also observed in other studies [18,26]. It also points to a possible limitation of the existing gold standard classification of Freeman and Wyke [4], modified by Hagert [8], because many sensory nerve endings apparently will not fit into the established and limited classification schemes.…”