Broken thumb

The thumb is the thickest and shortest finger and consists of two phalanges (small bones). The other fingers each have three phalanges. A fracture of the thumb means that there is a break in one or both phalanges.

Fracture involving the joint

The break can also extend into the joint; this is called intra-articular. The consequence of this type of break is an increased risk of early osteoarthritis of the thumb joint.

With such an intra-articular break there are two different types:

• A Bennett fracture - first described by Edward Bennett in 1882 - means that the base phalanx of the thumb is both broken and displaced (dislocated).
• A Rolando fracture - first described by Silvio Rolando in 1910 - means that the phalanx closest to the hand (base phalanx), has sustained multiple fractures (comminuted).

How does a broken thumb occur?

The most common cause of a broken thumb is a direct blow, knock or fall on the thumb. Think, for example, of a thumb caught in a car door, a fall from a bicycle, a fight or a heavy impact on the thumb during sport.

Signs of a broken thumb

A broken thumb is mainly recognised by pain on touch. In addition, it is not possible to move the thumb without pain. Due to the break, the thumb can swell and turn blue. Making a pinch grip, bringing the tip of the thumb and the tip of the index finger together, is often no longer possible with a broken thumb. If nerves are also pinched due to the break, the thumb can be numb or tingle.

How is a broken thumb diagnosed?

During the consultation with the GP or physiotherapist it is important that the cause of the thumb complaints becomes clear. After this, a physical examination will be carried out into the strength and movements that can be made with the thumb. During the examination several tests can be performed to find out whether the bone is really broken.

If necessary, an X-ray will be taken. On an X-ray the size, location and direction of the fracture line can be seen. The specialist can additionally choose a CT scan. The CT scan provides even more information about the type of break and how it can best be treated.

Treatment of a broken thumb

With a simple and displaced break, the doctor will choose to realign the piece of bone. This is done under local anaesthetic. The thumb, and to support it the entire hand, must then heal in plaster or a splint. This period usually lasts four to six weeks. After this period the thumb will feel stiff and muscle strength is considerably reduced.

With a more severe break, such as a Bennett or Rolando fracture, the doctor may choose to operate. During the operation the bone fragments are put back in the correct position and held together with fixation material. This fixation material often consists of a metal plate and small screws. After the operation the thumb will need plaster for four to six weeks.

After the plaster period it is important to start using the thumb properly again. It is advisable to enlist the help of a hand physiotherapist. They will first reduce the stiffness and then strengthen the thumb with exercises.