Authors of section

Authors

Fabio A Suarez, Aida Garcia

Executive Editor

Simon Lambert

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Dorsal approach to the 5th carpometacarpal joint

1. Indications

This approach is indicated for:

  • Intraarticular fractures of the 5th metacarpal base
  • Fracture-dislocations of the 5th carpometacarpal (CMC) joint
  • Tendon avulsion fractures of the extensor carpi ulnaris

It can also be used for the rare displaced extraarticular fractures of the 5th metacarpal base.

Skin incision of a dorsal approach to the 5th carpometacarpal joint

2. Surgical anatomy

The extensor tendons of the little finger converge slightly towards the center of the wrist joint.

Note: The dorsal sensory branch of the ulnar nerve and longitudinal veins must be protected.

The insertion of the extensor carpi ulnaris tendon is onto the ulnar side of the 5th metacarpal base.

Surgical anatomy of the dorsal aspect around the 5th carpometacarpal joint

3. Skin incision

Perform a curved skin incision, running parallel to the 5th metacarpal on the dorsoulnar margin and curving radially over the hamate bone.

Note: The dorsal sensory branches of the ulnar nerve are especially vulnerable in the proximal third of the incision.
Skin incision of a dorsal approach to the 5th carpometacarpal joint

4. Retraction of extensor tendons

Retract the extensor tendons radially together with the surrounding loose connective tissue.

Retract the dorsal sensory branch of the ulnar nerve to the ulnar side, possibly together with the extensor carpi ulnaris tendon.

Retraction of extensor tendons during a dorsal approach to the 5th carpometacarpal joint

5. Capsulotomy

A longitudinal capsulotomy is made in case of intraarticular fractures.

Often, there is already a tear in the capsule, which can be extended.

Capsulotomy of the 5th carpometacarpal joint

6. Pearl: marking the joint with a hypodermic needle

If a capsulotomy is not needed, mark the position of the joint with a hypodermic needle or a small K-wire. The position may be checked with an image intensifier. This helps to avoid inadvertent penetration of the joint with screws.

This technique is helpful with arthroscopically assisted surgery.

Marking the 5th carpometacarpal joint with a hypodermic needle

7. Wound closure

Cover the implant with the periosteum as far as possible; this helps minimize contact between the extensor tendons and the implant.

If an intertendinous connection has been cut, it should be repaired.

Cross section showing periosteum covering a plate fixation at the 5th metacarpal base
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