Swan neck deformity: My dad, who has had rheumatoid arthritis for many years, has recently developed a problem with the middle finger of his right hand. His specialist says it is something called a swan neck deformity, but can you tell me if the condition is as a result of his arthritis?
Although swan neck deformity can occur as a result of many things including muscle spasm, misalignment of a healing fracture of the middle bone of the finger and laxness of the ligaments in the hand and fingers, the most common cause is rheumatoid arthritis.
Although not as severe, he also has a deformity of his thumb as well. Could this also be a swan neck deformity?
The swan neck deformity of the fingers is so called because it resembles a swan's neck. This is due to flexion at the base of the finger, extension of the middle joint and flexion of the distal joint.
The condition can affect the four fingers but not usually the thumb as it has one less joint.
However, a variant of the condition called a duck bill deformity can affect this digit. When a person develops both a swan neck and duck bill deformity, the functional use of the hand can be severely compromised.
Yes, we've noticed that he is having difficulty with his grip, but can anything be done about it?
The main problem with these types of deformity is that they affect the functional use of the sufferer's hand. Those with mild to moderate degrees of the condition may lose the ability to perform pinch movement with the fingers, while in severe cases it may be impossible to close the finger, leading to considerable restrictions in terms of hand function.
Treatment is aimed at correcting the deformity and improving functional use. In mild to moderate cases special splints called ring splints will be used to correct the deformity. These are usually designed and fitted by an occupational therapist and the splints have the advantage of not only correcting the problem but also allowing the person to continue to use their hand.
If splinting doesn't work, what's the alternative treatment?
When splinting is unsuitable or unsuccessful for these types of contractures, the conditions can be treated with surgery. This aims to realign the joints or in some cases fuse the joints - a process called interphalangeal arthrodesis - allowing for optimal hand function.