Less common than ulnar collateral ligament injuries (game keepers thumb)
RCL is important in pinch and depression movements
RCL injury leads to static and dynamic instability
Grade 3 tears are usually treated surgically
Review article:
Edelstein DM et al. Radial Collateral Ligament Injuries of the Thumb. The Journal of Hand Surgery. Volume 33, Issue 5, May-June 2008, Pages 760-770