Support splinting of the thumb

A cast or splint is applied postoperatively. This allows for better pain and edema control and early mobilization of uninvolved joints.

Once swelling has subsided, the initial splinting may be changed to a thermoplastic splint.

The type of splint may vary depending on the injury type and should be decided on a case to case basis. Below is shown the application of a thumb spica splint.

Thumb spica splint (long)

A thumb spica splint with open 1st webspace helps to neutralize fracture displacing muscle forces and keep the fragments aligned.

This splint immobilizes the 1st MCP, 1st CMC, and wrist joints.

In proximal and diaphyseal metacarpal fractures, the IP joint should be left free to help with early EPL and FPL mobilization.

Thumb spica splint immobilizing the 1st MCP, 1st CMC, and wrist joints

The IP joint needs to be included in the splint if the fracture involves the MCP joint, eg, distal metacarpal fracture, tendon injuries, or any phalangeal fracture.

Thumb spica splint immobilizing the 1st IP, MCP, 1st CMC, and wrist joints

Thumb spica splint (short)

The thumb spica may be shortened leaving the wrist free. This may be used in ligamentous injuries and avulsion fractures of the MCP joint, eg, skier’s thumb.

Note: Phalangeal fractures may require additional immobilization of the wrist to neutralize the displacing extrinsic forces.

Thumb spica splint immobilizing the 1st IP, MCP, and 1st CMC joints

Immobilize the hand and wrist in a well-padded thumb spica splint with the wrist slightly extended and the 1st MCP joint immobilized in a position of abduction.

AO teaching video

Metacarpal and Phalanx—Fractures and Soft-tissue Injuries—Thumb Spica

Paul Demmer, Doron JM Frantzen, Nikolaas GJ Maritz

The thumb spica is a circular plaster cast used to immobilize the thumb. In this presentation the application of the thumb spica will be demonstrated.

Maintaining reduction of metacarpal injuries

During the application of the splint, it is important to maintain thumb abduction by pressure over the palmar aspect of the first metacarpal head and the dorsal aspect of the 1st metacarpal base.

Maintaining reduction of a carpometacarpal dislocation of the thumb during splint application

Pearl: Mold the splint with the thumb in abduction to maintain reduction. This adheres to the principle of three-point molding to maintain position.

Pitfall: Avoid pressing from the palmar aspect over the base of the proximal phalanx. This results in hyperextension of the MCP joint and redislocation of the CMC joint.

Molding the thumb spica splint to maintain reduction

Splinting

Protect the skin of the arm and hand with padding/cotton sleeve to avoid pressure sores, especially on the 1st webspace, distal ulna, and styloid process of the radius.

Thumb spica splint application - padding

Create a splint of several layers of cast bandage depending on the specific type of bandage available. It should cover the palmar half of the forearm, wrist, and thumb.

The wrist should be in neutral or slight extension.

Make sure that the splint does not extend too far distally, either at the level of the finger metacarpophalangeal (MCP) joints, or the interphalangeal joint of the thumb. The splint must not limit complete flexion of these joints.

Thumb spica splint application – allowing for full range of motion at the level of the joints of the fingers and IP joint of the thumb

The splint is held in place with an elastic bandage. The bandage should not be overtightened, especially at the level of the wrist joint and 1st webspace, to avoid pain and excessive swelling of the hand.

Direct skin contact with adjacent fingers should be prevented by placing gauze pads between them.

The patient should be instructed to add another elastic bandage if necessary.