Section 5. Bone, Joint, and Muscle Disorders

Chapter 71. Hand Disorders

Topics: Introduction | Ganglia | Deformities | Carpal Tunnel Syndrome | Cubital Tunnel Syndrome | Radial Tunnel Syndrome | Kienböck's Disease | Shoulder-Hand Syndrome | Injuries | Infections

Deformities

See the figure When the Fingers Are Abnormally Bent.

Hand deformities may be caused by an injury or may result from another disorder (for example, rheumatoid arthritis (see Section 5, Chapter 67)). Deformities should be treated promptly, if possible. Otherwise, they tend not to respond to simple treatments, such as splinting or exercises, and often require surgery.

Mallet Finger

Mallet finger is a deformity in which the fingertip is curled in and cannot straighten itself.

This deformity usually results from injury, which either damages the tendon or tears the tendon from the bone. It can affect one or more fingers. A doctor can make the diagnosis by examining the finger. An x-ray is usually taken to be sure that there is no fracture. The usual treatment is placing a splint on the finger with the finger straightened. The tendon may take 6 to 8 weeks to heal. Mallet finger rarely requires surgery, unless a large fragment of bone has broken off or the joint is partially dislocated, even in the splint.

Swan-Neck Deformity

Swan-neck deformity is a bending in (flexion) of the base of the finger, a straightening out (extension) of the middle joint, and a bending in (flexion) of the outermost joint.

The most common cause is rheumatoid arthritis. Other causes include untreated mallet finger, looseness (laxity) of the fibrous plate inside the hand at the base of the fingers or of the finger ligaments, muscle spasm affecting the hands, and a misalignment in the healing of a fracture of the middle bone of the finger. Closing the finger may become impossible; the deformity can therefore result in considerable disability.

True swan-neck deformity does not affect the thumb, which has one less joint than the other fingers. However, in a variant of swan-neck deformity, called duck-bill deformity, the top joint of the thumb is severely overstraightened with a bending in of the joint at the base of the thumb to form a 90° angle. If duck-bill deformity and swan-neck deformity of one or more fingers occur together, the ability to pinch can be seriously reduced.

A doctor makes the diagnosis by examining the hand and finger. Treatment is aimed at correcting the underlying cause when possible. Mild deformities may be treated with finger splints (ring splints), which correct the deformity while still allowing a person to use the hand. Problems with the ability to pinch can be greatly improved by surgically realigning the joints or by fusing the thumb or finger joints together (called interphalangeal arthrodesis) into positions that allow for optimal function.

Boutonnière Deformity

Boutonnière deformity (buttonhole deformity) is a deformity in which the middle finger joint is bent in a fixed position inward (toward the palm) and the outermost finger joint is bent excessively outward (away from the palm).

This disorder most often results from rheumatoid arthritis (see Section 5, Chapter 67) but can also occur from injury (deep cuts, joint dislocation, fractures) or osteoarthritis (see Section 5, Chapter 66). People with rheumatoid arthritis can develop the disorder because they have long-standing inflammation of the middle joint of a finger. If the deformity is due to an injury, the injury usually occurs at the base of a tendon (called the middle phalanx extensor tendon). As a result, the middle joint (called the proximal interphalangeal joint) becomes "buttonholed" between the outer bands of the tendon that runs to the end of the finger. The deformity can, but need not, interfere with hand function. The doctor makes the diagnosis by examining the finger.

A boutonnière deformity caused by an extensor tendon injury can usually be corrected with a splint that keeps the middle joint fully extended for 6 weeks. When splinting is ineffective, or when buttonhole deformity is due to rheumatoid arthritis, surgery may be needed.

Erosive (Inflammatory) Osteoarthritis

Erosive (inflammatory) osteoarthritis is a form of hereditary osteoarthritis that, in the hand, causes swelling, pain, and formation of cysts on the finger joints (particularly the outermost ones).

Osteoarthritis of the hand is apparent by enlargement of bones over the outermost joints of the fingers (Heberden's nodes) and overgrowth of bones over the middle joints of the fingers (Bouchard's nodules). With erosive osteoarthritis, there is also swelling of surrounding tissues. The joints between the fingers and hand and the wrists are usually not affected. The involved joints can become misaligned.

The deformity can be seen on x-rays. Unlike in rheumatoid arthritis, results of blood tests that indicate inflammation (such as the erythrocyte sedimentation rate [ESR] and the numbers of white blood cells) are usually normal, regardless of how severe the disorder is.

Treatment includes range-of-motion exercises in warm water to relieve pain during the exercises and to keep the joints as flexible as possible, splinting intermittently to prevent deformity, and use of analgesics or nonsteroidal anti-inflammatory drugs (NSAIDs) to relieve pain and swelling. Occasionally, a corticosteroid suspension may need to be injected into severely affected joints to relieve pain and increase range of motion. Rarely, when osteoarthritis is advanced and other treatments are not effective, the joint may need to be reconstructed or fused surgically.

Dupuytren's Contracture

Dupuytren's contracture (palmar fibromatosis) is a progressive shrinking of the bands of fibrous tissue (called fascia) inside the palms, producing a curling in of the fingers that eventually can result in a clawlike hand.

Dupuytren's contracture is a common hereditary disorder that occurs particularly in men and especially after age 45. However, having the abnormal gene does not guarantee that someone will have the disorder. The prevalence of Dupuytren's contracture in the United States is about 5%; the prevalence worldwide ranges from 2 to 42%. The disorder affects both hands in 50% of people; when only one hand is affected, the right hand is involved twice as often as the left.

Dupuytren's contracture is more common in people with diabetes, alcoholism, or epilepsy. The disorder is occasionally associated with other disorders, including thickening of fibrous tissue above the knuckles (Garrod's pads), shrinking of fascia inside the penis that leads to deviated and painful erections (penile fibromatosis [Peyronie's disease] (see Section 21, Chapter 238)), and nodules on the soles of the feet (plantar fibromatosis). However, the precise mechanism that causes the fascia of the palm to thicken and curl in is unknown.

The first symptom is usually a tender nodule in the palm (most often at the third or fourth finger). The nodule may initially cause discomfort but gradually becomes painless. Gradually, the fingers begin to curl. Eventually, the curling worsens, and the hand can become arched (clawlike). The doctor makes the diagnosis by examining the hand.

See the figure What Is Trigger Finger?

An injection of a corticosteroid suspension into the nodule may help decrease the tenderness in the area but will not delay progression of the disorder. Surgery is usually needed when the hand cannot be placed flat on a table or when the fingers curl so much that hand function is limited. Surgery to remove the diseased fascia is difficult, because the fascia surrounds nerves, blood vessels, and tendons. Dupuytren's contracture may recur after surgery if removal of the fascia was incomplete. It may also recur spontaneously, especially in people in whom the disorder appeared at a young age, those with the disorder running in the family, and those with Garrod's pads, Peyronie's disease, or nodules on the soles of the feet.