What Is Swan Neck Deformity?
Swan neck deformity is a deformity of the finger wherein the joints are bent towards the opposite of their natural positions and resemble a swan’s neck. In medical terms, Swan neck deformity is called DIP (distal interphalangeal joint) flexion with PIP (proximal interphalangeal joint) hyperextension.1
Causes of Swan Neck Deformity
Any condition which causes the PIP joint to loosen and hyperextend can cause a swan neck deformity of the finger. Rheumatoid arthritis is a common condition which causes Swan neck deformity.2 The PIP joint is chronically inflamed in rheumatoid arthritis. Due to this, the PIP joint becomes loose and bends back into hyperextension. The extensor tendon loses balance and the DIP joint gets pulled down into flexion. As the DIP joint flexes and the PIP joint hyperextends, swan neck deformity occurs.
Symptoms of Swan Neck Deformity
Inflammation due to injury or rheumatoid arthritis can cause swelling and pain of the PIP joint. The DIP flexes and the PIP hyperextends, leading to the swan neck shape of the finger which is termed swan neck deformity.
Diagnosis of Swan Neck Deformity
The Swan neck deformity is pretty much evident to the naked eye. The doctor may order an X-ray to check for any fracture and to check the condition of the joint surfaces and examine the joint alignments.3
Treatment of Swan Neck Deformity
Treatment for swan neck deformity varies on whether the PIP joint is flexible or not.
Conservative Treatment of Swan Neck Deformity
If the PIP joint is supple and flexible, then the treatment for Swan neck deformity will be based on restoring balance in the structures of the hand and fingers. Effort will be made to align the PIP joint and prevent hyperextension to help restore DIP extension. If these measures do not work, a surgical approach may be required to correct Swan neck deformity.
Professional rehabilitation in the form of physical or occupational therapy will help address the imbalances that have caused the swan neck deformity. Stretching, massage, and joint mobilization are used to try to restore finger alignment and function.
A splint may be used to keep the PIP joint lined up, avoid hyperextension and still allow movement of the PIP joint. The PIP joint needs to be supple for this approach to be successfully used.
A six week course of splinting and a therapy program will be followed to improve PIP joint mobility before performing surgery.
Surgical Treatment of Swan Neck Deformity:
- In cases where splinting fails to correct Swan neck deformity, surgical reconstruction of the structures around the PIP joint may be required. Following surgery, a well designed and rigorous exercise program needs to be followed for early recovery from Swan neck deformity.
- In cases of swan neck deformity where the PIP joint is stiff, arthroplasty is required. A new implant is put in place of the old surfaces of the PIP joint and ensures the new joint can move easily.
- In cases of rheumatoid arthritis, when a mallet deformity occurs, the DIP joint can be fused. This aids in easing pain, stabilizing the joint, helps prevent additional deformity. PIP joint fusion is recommended when past treatments, including surgery, do not stop inflammation or deformity in the PIP joint.
Recovery Period for Swan Neck Deformity
With surgical treatment, the patient wears a splint/brace right after surgery to correct Swan neck deformity. At least three weeks later, physical or occupational therapy treatment starts. PT for Swan neck deformity goes on for 3-4 months. Full recovery post surgery for Swan neck deformity takes 6 months approximately.