Dorsal approach to the metacarpophalangeal (MCP) joint of the thumb
This approach is indicated for intraarticular, or periarticular, fractures of the metacarpophalangeal (MCP) joint of the thumb. It is also used for arthrodesis of the MCP joint.
2. Skin incision
A straight, or gently curved, skin incision can be used. Start the incision 2 cm proximal to the MCP joint, extending it to approximately 2 cm distal to the MCP joint. Identify and protect the dorsal divisions of the dorsal sensory branch of the radial nerve, and the dorsal veins.
3. Exposure of the extensors
Elevate the skin and fine subcutaneous tissue as a single layer, by blunt dissection, and expose the tendons of extensor pollicis longus (EPL) and extensor pollicis brevis (EPB).
4. Splitting of the tendon
Incise between the EPL and the EPB tendons.
Be careful not to detach the insertion of the EPB from the base of the proximal phalanx.
After separating the extensor tendons, the joint capsule is exposed. A longitudinal capsulotomy is performed to enter the joint. Take care not to detach the collateral ligaments.
Exposure of the joint
Flex the thumb in order to expose the MCP joint fully.
6. Wound closure
Repair the capsulotomy with fine, interrupted mattress sutures. The separated tendons of EPL and EPB are approximated with sutures.