BENNETT'S FRACTURE

GENERAL

A Bennett's Fracture is a fracture + dislocation of the Metacarpal bone at the base of the thumb.

The fracture involves the joint surface and is often significantly displaced. This is a highly unstable injury and occurs commonly in football.



Many people think that a "fracture" is different from a "break", but they are the same.



From a functional view the thumb is as important as the other 4 fingers put together. An inadequately treated Bennett's fracture can result in an uneven joint surface at the base of the thumb and predispose to late onset arthritis in this joint. This can have a significant impact on overall hand function.

When the forces are severe the bone may end up in multiple pieces (the fracture is then called a Rolando fracture.)

When a bone breaks there is bleeding from the bone ends. Bleeding leads to swelling which results in stiffness particularly in the fingers and thumb.

TREATMENT OF BENNETT'S FRACTURE

"Reduction" means pulling the bones back into place. This can be done "Closed" in which no cut is made and a plaster or splint is applied or "Open" where a cut is performed and the bones are directly repositioned. An open reduction often requires the use of wires, plates and screws.

1. Control and Reduce Swelling

• Ice Packs.
• Elevation.

2. Wire and Plaster

It is inadequate to treat this unstable fracture with plaster treatment alone. After the fracture is reduced a wire is inserted through the skin and a plaster applied.

Advantages...

• No cut.
• Less dissection of muscle.
• Less risk infection.
• Smaller procedure.

Disadvantages...

• Plaster for 6 weeks.
• Must keep dry.
• Increased stiffness.
• Increased risk of late infection along wire.

3. Open Reduction

Involves cut at base of thumb and insertion of screws and/or wires across the fracture site.

Advantages...

• Allows accurate alignment of joint surface under direct vision.
• Gentle movements may be started early if screw fixation is noted to be strong at time of surgery.

Disadvantages...

• Cut over base of thumb involves muscle dissection to expose the joint.
• Increased risk of injury to skin nerves.
• Increased risk of early infection.

An open reduction using 1 or 2 screws is usually the preferred option in treatment. At the end of the procedure the screw position is checked using a special X-ray machine in the operating theatre.

  

RESULTS

Stiffness is the most common problem and so movement is started as soon as it is safe to do so. Please closely follow the recommendation of your surgeon and hand therapist.

It is common for the thumb to feel weak for 6 months after this injury.

Occasionally loss of bone alignment occurs and additional treatment may be required.

In general it takes 6 weeks for a hand fracture to heal and at least another 6 weeks for it to remodel and consolidate.