The finger is a perfectly balanced anatomic structure. There are many important factors at play which ensure normal finger movement and correct positioning. When something disturbs this balance, the finger’s normal alignment and function may also be disturbed. This can result in what is called a ‘swan neck’ deformity where the finger becomes crooked due to a collapse in the equilibrium of structures supporting the finger.
Causes of swan neck deformity
A swan neck deformity results in hyperextension of the PIP joint and flexion of the DIP joint in the finger. This condition can be the result of a volar plate injury, when the finger is forced into hyperextension, or be associated with hyper mobility after a mallet finger injury. It may be due to destabilisation of the joint associated with an inflammatory disease (such rheumatoid arthritis).
Symptoms
The most prominent symptom of a swan neck deformity is, of course, the deformed finger, whereby the PIP joint is bent up in hyperextension and the DIP joint is bent downward in flexion. Moving the finger might be difficult and painful, and in particular, it may become difficult to initiate making a fist if the joint locks into extension.
Treatment from your hand therapist
Most swan neck deformities can be treated successfully without surgery.
Treatment involves splinting of the finger to prevent the PIP joint from moving into hyperextension. It will help to restore the tendon balance and allow the finger to function normally.
Surgical treatment
Surgical review may be required if the swan neck deformity does not respond to conservative treatment. More chronic cases of conditions that cause swan neck deformities may also require surgery. Your therapist can discuss with you and your GP and arrange a referral to a surgeon if required.
If you are suffering from swan neck deformity in the finger, or any other issues with the hand, arm or fingers, please feel free to get in touch with the Hand Therapy Group here, we’d be more than happy to help.