Mallet finger injuries are injuries that occur to the tendon responsible for straightening the tip of our finger. They are classified as a flexion deformity injury due to the inability of the individual to straighten their fingertip. This results in a fingertip that is held in a bent or flexed position.
Anatomy
Tendons are what connect muscles to our bones. They are responsible for transferring force generated in our muscles to our bones so that we can move our joints. The extensor tendons in our hands are responsible for straightening (extending) our fingers. These tendons are found on the back of our hands and run to the fingers.
Mallet finger injuries occur when either there is a rupture of the extensor tendon, or an avulsion injury. An avulsion injury is when the extensor tendon pulls a piece of the bone it’s attached to, off the finger. In both circumstances there is complete dysfunction of the extensor tendon, resulting in an inability to straighten the fingertip.
Causes
Mallet finger injuries commonly occur in the sporting population. The most common cause of injury is taking a blow and forcing the tip of the finger into excessive flexion or hyperextension. This can routinely happen when playing sports such as basketball or baseball when the finger is jammed by the ball itself. However, mallet finger injuries can also occur around the home – for example, if the individual hits his or her fingertip with a hammer.
Signs and Symptoms
Signs and symptoms of a Mallet finger injury can include but are not limited to:
- Pain and tenderness around the fingertip and joint
- Swelling and redness around the fingertip and joint
- Inability to actively straighten fingertip
Examination
All patients with a suspected mallet finger injury should have an x-ray to determine if there is any bony involvement (avulsion injury) or not.
Range of movement testing should also be completed. Patients with this type of injury will not actively be able to extend their fingertip.
Strength testing can be completed as appropriate, but extension strength will be absent in these patients.
Management
Early management for mallet finger injuries is crucial to allow for adequate healing of the bone or tendon. If left untreated, a mallet finger injury will not heal and is likely to develop osteoarthritis or a permanent flexion deformity will occur. This is called a ‘swan neck’ deformity.
Standard treatment is immobilising the injured finger in an extension splint for 8 weeks. Extension splints can successfully be fitted by a physiotherapist. The splint must always be worn, 24 hours a day, to allow for healing. Patient compliance is often the most important factor in determining treatment success.
In the early stages ice can also be applied to help manage swelling and pain.
If conservative management fails, surgery may be considered. This is usually done approximately 6 months after the injury. Surgery often involves insertion of a wire into the finger and direct repair of the tendon itself. If a fracture is present, surgery may be considered at an earlier stage depending on the size and type of fracture.
Physiotherapy
Physiotherapy will be of particular importance once the splint is removed. Manual therapy, such as soft tissue massage and joint mobilisation, can assist in restoring normal movement and function to the finger and hand.
Prescription of a progressive exercise program assists in restoring range of motion and strength to allow patients to gradually return to normal everyday activities.