The Role Of The Carpometacarpal Ligaments Of The Thumb In Stability And The Development Of Osteoarthritis Lesions : An Anatomical Study

Abstract

This study aims to assess ligament lesions and subluxations of the carpometacarpal (CMC) joint of the thumbs and the role that these ligament ruptures play in the pathophysiology of osteoarthritis (OA). Twenty-five fresh-frozen cadaver hands were dissected. There were 14 female and 11 male with mean age 65 years (51-92 years old). The origin, insertion, and fibre orientation of the ligaments were identified based on Berger´s anatomical descriptions. Length, thickness and width of the main ligaments were measured. The ligament ruptures and the metacarpal translation associated with these ruptures were measured (mm). Cartilage thickness in the trapezium and metacarpal of specimens was assessed. We investigated the relationship between the ligament ruptures and the area of chondromalacia and OA. In the specimens that showed an isolated or combined rupture in DRL we found a significant increase in the dorsal translation of metacarpal with a mean of 1.7 mm. Statistical analysis of data demonstrates a significant difference (P = 0.006). There was a relationship between the presence of a tear in the DRL and OA in the radial quadrants (P = 0.032). These observations suggest a translation of metacarpal on trapezium in the production of arthritic lesions and support a hypothesis that pathologic joint instability could be a cause of CMC osteoarthritis. This study suggests that repairing the DRL during ligament reconstruction of the CMC joint should be considered.