Review Question - QID 219854

This patient presents with a traumatic dislocation of the carpometacarpal (CMC) joint with persistent joint incongruity following closed reduction. The dorsoradial ligament complex is the primary restraint to dorsal dislocation and subluxation (Answer/Structure 1).

A ligamentous dislocation at the first CMC joint is uncommon and accounts for less than 1% of all hand injuries. There is a paucity of clinical evidence, owing to the rarity of the injury pattern. Cadaveric studies demonstrate that, in all positions, the dorsoradial ligament is the main stabilizer against a dorsal force. The initial management of this injury in the acute setting is closed reduction and thumb spica immobilization. If a congruent joint cannot be obtained, level 5 evidence recommends closed reduction and percutaneous fixation with possible open capsulorrhaphy and/or ligament reconstruction.

Strauch et al. published the results of a cadaveric study in which 33 specimens had one thumb CMC joint ligament sectioned, followed by the application of a dorsal-directed force. The dorsoradial ligament was found to be the main restraint to dorsal dislocation as sectioning of the ligament demonstrated the largest degree of joint subluxation.

Esplugas et al. published a follow-up study of 11 fresh frozen cadavers. The authors sectioned one of three groups of ligaments (dorsal, volar, or ulnar) and then measured the translation of the CMC joint with external forces. The authors concluded that sectioning the dorsoradial ligament group resulted in the greatest dorsoradial translation.

Bosmans et al. published a review article on the anatomy, pathophysiology, and treatment of CMC joint dislocations. The authors acknowledge the limited evidence on the topic and recommend acute injuries be closed reduced and placed in thumb spica immobilization for 6 weeks. If closed manipulation fails, they recommend temporary percutaneous joint fixation or open reduction, temporary joint fixation, and capsulorrhaphy and/or ligament reconstruction.

Figure A shows the ligamentous stabilizers of the thumb CMC joint from a volar and dorsal perspective.

Incorrect Answers:
Answer 2: This is the dorsal central ligament.
Answer 3: This is the posterior oblique ligament.
Answer 4: This is the ulnar collateral ligament.
Answer 5: This is the anterior oblique ligament.