Joint dislocation, with or without small bony or ligamentous avulsions, may be reduced closed, and the stability should then be evaluated. Often more than one carpometacarpal (CMC) joint is affected.
If closed reduction is not successful, obstructing soft tissues or fragments need to be removed by exposure of the affected CMC joints.
If there is persistent instability, the joint may be stabilized with a temporary K-wire. In noncompliant patients, K-wire stabilization is recommended.
Place the patient supine with the arm on a radiolucent hand table.
A dorsal approach to the affected CMC joints may be used.
If only the 5th CMC joint needs exposure, an approach to this joint may be used.
Protect the dorsal sensory nerve branches (radial and ulnar).
Dislocation is usually dorsally and may be reduced manually in a closed manner.
Open reduction is indicated if there are interposed soft tissue or bony fragments. Often, the joint capsules are ruptured, and the joint space is easily exposed.
Remove any soft tissue or bony fragments and reduce the joint.
Confirm reduction with an image intensifier and check the joint stability by passive flexion and extension of the fingers.
Often there is persistent instability, eg, subluxation or redislocation during the range of motion. In this case, add a temporary K-wire:
Repair the capsule if an open reduction was performed.
Bend the end of the K-wire above the skin and cut it with enough length to avoid migration.
This case shows K-wire stabilization of the 5th to the 4th metacarpal base and the hamate.
The aftercare can be divided into four phases of healing:
Full details on each phase can be found here.
Support the hand with a dorsal splint for about 2–4 weeks. This would allow for finger movement and help with pain and edema control. The arm should be actively elevated to help reduce the swelling.
To facilitate rehabilitation, it is important to control the postoperative pain adequately.
X-ray checks of joint position have to be performed immediately after the splint has been applied.
Follow-up x-rays with the splint should be taken after 1 week and possibly every 2 weeks.
The K-wire can be removed 4–6 weeks after surgery.
Splint immobilization is continued until about 4 weeks after the injury. At that time, an x-ray without the splint is taken to confirm healing, and range of motion should be pain-free.
Splinting can then usually be discontinued, and active mobilization is initiated. Functional exercises are recommended.
This case shows a dislocated 5th CMC joint.
In the lateral x-ray, the dislocation is seen most prominently.
AP and oblique x-rays showing the hand in a splint with the CMC joint reduced
Lateral view