Causes of Swan Neck Deformity
At first glance, diagnosing Swan Neck Deformity seems like a "no brainer". You have visual confirmation of hyperextension of the proximal interphalangeal (PIP) joint and flexion of the distal interphalangeal (DIP). The finger is contorted into the shape of a swan neck. And, your patient has Rheumatoid Arthritis (RA).
Yes. Swan Neck Deformity does show up in about half of all RA patients; but, there are a surprising number of other causes, including Cerebral Palsy, Lupus, Stroke, Parkinson’s Disease (PD), Ehlers-Danlos Syndrome (EDS), Marfans, post-traumatic flexor tendon ruptures and ischemic injuries.
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To boot, this is not a matter-of-fact condition. Over time, this malformation becomes a significant and painful disability as the imbalance between muscles and tendons progresses. The patient loses the capacity for bending, pinching, gripping, and grasping. If treated incorrectly or left untreated, muscles may contract permanently and joint capsules may rupture.
Evaluating Patients for a Swan Neck Deformity
Swan Neck Deformity patients need a careful evaluation to determine the severity and sources of their PIP hyperextension and DIP flexion. For example, is the hyperextension caused by extrinsic extensor tightness? Is the intrinsic tightness caused by spasticity pertaining to CVA or PD? Is the DIP flexion a result of weakened, disrupted, or perhaps a ruptured terminal extensor tendon?
A thorough examination will more precisely define the severity of the deformity, precise alignment issues, and the best means for correcting the mechanics. (See bottom of page for Nalebuff classification.)
Particularly with Swan Neck Deformity, proper diagnosis and early intervention are key to successful management and finding the best means of righting the imbalance. Physical and occupational therapy, based on the root cause and severity of the deformity, may include daily massage, stretches, and exercise.
Treating Swan Neck Deformity
Splints are an integral part of treatment for re-aligning the joints. Oval-8 Finger Splints that block hyperextension without limiting flexion are often very successful long-term solutions in patients with mild to moderate Swan Neck Deformity. These comfortable, unobtrusive splints keep the finger in proper alignment and prevent hyperextension at the PIP joint. When hyperextension at the PIP joint is controlled, the ability to control motion at the DIP joint is also improved.
In severe cases, surgical options should be considered and may include soft tissue repair, arthroplasty, replacement, or fusion. Splinting is indicated prior to and following surgery.
With careful adherence to splinting and therapy, most Swan Neck Deformity patients can regain and maintain balance and function in the finger.
In 1989, Hand Clinics (Elsevier) published “The rheumatoid swan-neck deformity” by orthopedic surgeon Edward A. Nalebuff, MD, FACS. Today, Dr. Nalebuff’s classification is used to guide the treatment choices for patients with swan neck deformities. Dr. Nalebuff, who received his medical degree from Tufts University School of Medicine in 1953, retired in 2014.
The Nalebuff classification of swan-neck deformities
- Type I - proximal interphalangeal joints are flexible in all positions.
- Type II - proximal interphalangeal joint flexion is limited in certain positions.
- Type III - proximal interphalangeal joint flexion is limited in all positions.
- Type IV - proximal interphalangeal joints are stiff and have a poor radiographic appearance.)