- Dorsal approach to the MCP joint
This approach is indicated for intraarticular fractures of the metacarpal head, injuries of the metacarpophalangeal (MCP) collateral ligaments (either avulsion fractures or ligament ruptures), and intra- or extraarticular fractures of the base of the proximal phalanx.
The tendons of the extensor digitorum and the extensor hood cover the MCP joints dorsally. The extensor tendon receives the insertions of the tendons of the interosseous and lumbrical muscles via the extensor hood.
Proximal to the index MCP joint, the extensor indicis tendon lies ulnar to the extensor digitorum tendon, and at the little finger, the extensor digiti minimi tendon is ulnar to the extensor digitorum tendon.
Make a gently curved longitudinal incision over the MCP joint.
Depending on the fracture pattern, the incision is placed over the dorsoradial or dorso-ulnar aspect of the MCP joint. In general, a radially curved incision is preferred over the second MCP joint, and a dorsoulnar curved incision over the fifth MCP joint.
Extension of the incision
If necessary, the incision can be extended distally or proximally in a curvilinear or longitudinal manner.
Exposure of the extensor apparatus
The skin flap is elevated from the extensor apparatus, without damaging the surrounding loose connective tissue, the sensory nerve branches or the longitudinal veins.
Exposure of the joint capsule
The extensor digitorum tendon can be split longitudinally. In the index and little fingers, the incision can be made between the two extensor tendons.
Alternatively, the extensor hood can be incised parallel to the extensor digitorum tendon, leaving a small fringe for subsequent repair. Depending on the fracture pattern, the incision is dorso-ulnar or dorsoradial. In general, a dorso-ulnar incision is preferable to prevent subluxation of the extensor tendon to the ulnar side, should the repair fail.
In general, a longitudinal capsulotomy is made to open the MCP joint.
The joint capsule is repaired with fine sutures. The extensor tendon can be repaired with a running suture, using either slowly resorbable or non-resorbable material.