The dorsoradial ligament is the thickest and most consistently present of the dorsal thumb CMC ligaments, running from the dorsoradial surface of the trapezium to the dorsoradial base of the first metacarpal. Recent biomechanical studies have challenged the traditional view of the AOL as the sole primary stabiliser, with some evidence suggesting the dorsoradial ligament plays an equal or greater role in resisting metacarpal dorsal subluxation.
Resists dorsal and radial subluxation of the first metacarpal on the trapezium during lateral and tip pinch loading, and maintains dorsal joint capsule integrity during the wide arc of thumb opposition.
The dorsoradial ligament is the structure most consistently found to be attenuated or absent at the time of surgery in patients with CMC arthrosis, leading some surgeons to use it as the primary target for ligament reconstruction rather than the AOL. Eaton staging of thumb CMC arthrosis correlates with progressive dorsoradial ligament failure. The ligament is accessible through the dorsoradial surgical approach used for CMC arthroplasty and reconstruction.
Isolated dorsoradial ligament laxity produces a palpable laxity on the dorsal-radial aspect of the first CMC joint with a subluxation click on loading, often managed with thumb-based splinting and, if symptomatic, ligament imbrication or reconstruction.
