CPT® Code 26820

Fusion in opposition of the thumb at the carpometacarpal (CMC) joint is a surgical procedure primarily aimed at addressing conditions such as arthritis or instability affecting the joint. The CMC joint is crucial for thumb movement, particularly for opposition, which is the action of bringing the thumb across the palm towards the small finger. This procedure involves several technical steps, including making an incision on the lateral side of the thumb to access the CMC joint. The surgeon inspects the joint surfaces by incising the joint capsule and excising any damaged articular cartilage from both the metacarpal base and the trapezium bone. To ensure proper fit and function, the trapezium is reshaped using a bur. A bone autograft, typically harvested from the iliac crest, is then prepared to fill the defect created during the procedure. The graft is secured in place using internal fixation methods, such as pins or wires, to maintain the thumb's position in opposition while the joint heals and fuses. Finally, the soft tissues are meticulously repaired, and a short arm cast is applied to support the recovery process.