gms | German Medical Science

Objectives/Interrogation: Early biomechanical studies focus on the volar beak ligament as the primary stabiliser of the thumb carpometacarpal joint (CMCJ). However, more recent work summarised in a systematic review highlights the role of dorsal ligament complex (DLC) in stabilising the joint.

A common approach to stabilising the thumb CMCJ joint uses flexor carpi radialis to reconstruct the ligament, akin to an LRTI following trapeziumectomy.

Alternative approaches that account for the role of the DLC exist, such as Rayan's dorsoradial capsulodesis. However, such techniques tend to focus on one joint structure or the other.

We describe a novel modification of the FCR-based technique that simultaneously reconstructs the volar beak ligament and to DLC, and its use in a challenging case.

Methods: A 28-year-old right handed was treated for a recurrent left thumb CMCJ dislocation. The closed injury was sustained two months earlier in a motorbike road traffic collision and was initially treated with closed reduction and k wire fixation. However, the dislocation recurred after the wires were removed after 4 weeks.

Under regional block and tourniquet control, the FCR tendon was identified and divided proximally in the forearm and reflected into the hand maintaining its insertion. A drill hole was made through the base of the metacarpal and the cut end of FCR passed through this from volar to dorsal, as would be performed in an LRTI. This reconstructs that volar beak ligament.

Instead of immediately pulling the FCR around the metacarpal base and suturing it to itself as would be done in an FCR, the FCR was anchored to the dorsoradial aspect of the trapezium. This reconstructed the DLC.

This approach was supported by the biomechanical studies identified in a contemporary, PROSPERO-registered systematic review that combined index and free text searching of multiple databases.

Results and Conclusions: On table, the novel CMCJ stabilisation achieved immediate stability of the CMCJ throughout passive range of motion and was confirmed with image intensifier control.

The patient continues to make a good recovery.

In the systematic review, 55 studies were included of 345 identified from searches. The evolving understanding of the roles of the volar beak ligament and DLC from 1973 to the present demonstrates the importance of both.

This simple modification of CMCJ stabilisation demonstrates how systematic reviews can impact on clinical hand surgery practice.