Hand Deformities

Geriatric Essentials

• Osteoarthritis (degenerative joint disease) is a common cause of pain and decreased hand function in the elderly. Erosive osteoarthritis, an inflammatory form, often produces deforming bony overgrowth of the proximal interphalangeal and distal interphalangeal joints.

Deformities can result from generalized disorders (eg, arthritis) or dislocations, fractures, and other localized disorders. Once a hand deformity becomes firmly established, it cannot be significantly altered by splinting, exercise, or other nonsurgical treatment.

Mallet finger: Mallet finger is a flexion deformity of the distal interphalangeal (DIP) joint in which the distal phalanx is flexed and cannot be extended (see Figure 55-1). This deformity may result from a tendon rupture or an avulsion fracture of the tendon's insertion. The joint may be only minimally flexed during the first few weeks after the injury. Closed injuries may be treated with splinting that holds the DIP joint in extension and leaves the proximal interphalangeal (PIP) joints free. Pure tendon injuries require about 8 to 10 wk for the collagen to heal sufficiently, whereas avulsion fractures are usually united after 6 wk. Surgery may be necessary to preserve function and prevent osteoarthritis if a fracture involves a large proportion of the joint surface or if the joint is subluxated.

Swan-neck deformity: Swan-neck deformity is hyperextension of the PIP joint, flexion of the DIP joint, and sometimes flexion of the metacarpal joint (see Figure 55-2). This deformity is characteristic of RA. Other causes include untreated mallet finger, volar plate ligament laxity, spasticity of the intrinsic hand muscles, entrapment or rupture of the flexor digitorum superficialis tendons that flex the proximal interphalangeal joints, and malunion of a fracture of the middle or proximal phalanx. Inability to overcome hyperextension of the PIP joint makes finger closure impossible and can cause severe disability.

True swan-neck deformity does not affect the thumb, which has only one interphalangeal joint. However, severe hyperextension of that joint with flexion of the metacarpophalangeal (MCP) joint (called a duck bill, Z [zigzag] type, or 90°-angle deformity) may occur. If the thumb is unstable, swan-neck deformity can greatly impair prehension. Swan-neck deformity can usually be corrected surgically; the underlying disorder is treated when possible (eg, by correcting the mallet finger or any bony misalignment, by rebalancing the extensor mechanism, or by releasing spastic intrinsic muscles).

Boutonnière deformity: Boutonnière deformity is flexion of the PIP joint and hyperextension of the DIP joint. Causes include tendon rupture, dislocation, fracture, osteoarthritis, and RA. Characteristically, disruption of the central slip of the middle phalanx extensor tendon creates so-called buttonholing of the proximal phalanx between the lateral bands of the extensor tendon (see Figure 55-2). Splinting may be effective if implemented before scarring develops. Surgical reconstruction is difficult and may be unsatisfactory.

Erosive (inflammatory) osteoarthritis: Erosive osteoarthritis is a form of osteoarthritis in the hand in which the DIP joints, some PIP joints, and the 1st carpometacarpal joints are genetically predisposed to extensive synovitis and cyst formation. Bony overgrowth of DIP (Heberden's nodes) and PIP (Bouchard's nodes) joints is present, often without significant soft-tissue swelling. Erosive osteoarthritis does not usually affect the MCP joints or wrists. On x-ray, erosions appear subchondral rather than marginal (as they usually appear in RA). The thumb base (carpometacarpal joint) is frequently involved and has a squared-off appearance. Erosive osteoarthritis does not normally produce systemic illness or significantly increase the ESR, but C-reactive protein may be mildly increased.

Treatment includes range-of-motion exercises in warm water, intermittent splinting as needed to prevent deformity, analgesics or NSAIDs, and occasional intra-articular injections of corticosteroid suspension to relieve pain and facilitate mobility of acutely symptomatic joints.

Dupuytren's contracture (palmar fibromatosis): Dupuytren's contracture is progressive contracture of the palmar fascial bands, producing flexion deformities of the fingers (see Figure 55-3). Dupuytren's contracture is common; the incidence is higher in men and increases after age 45. This autosomal dominant disorder with variable penetrance occurs most commonly in patients with diabetes, alcoholism, or epilepsy. However, the factor that causes the palmar fascia to thicken and contract is unknown.

The earliest manifestation is usually a tender nodule in the palm (most often at the base of the 3rd or 4th finger); it usually becomes nontender. Later, a superficial cord forms, which leads to contracture of the MCP and interphalangeal joints. Eventually, the contracture may worsen, and the hand can become arched. Some patients have fibrous thickening of the dorsum of the PIP joints (Garrod's pads), and about 7% of male patients develop Peyronie's disease. Rarely, Dupuytren's contracture develops on the plantar surface of the feet (plantar fibromatosis). Other types of flexion deformities of the fingers can occur with diabetes, systemic sclerosis, and chronic reflex sympathetic dystrophy, which need to be differentiated.

Injection of a corticosteroid suspension into the nodule can relieve local tenderness if given before contractures develop. If the hand cannot be placed flat on a table or, especially, if significant contracture develops at the PIP joints, surgery is usually indicated. Excision of the diseased fascia must be thorough because it surrounds neurovascular bundles and tendons. Incomplete excision or new disease results in recurrent contracture, especially in patients who are young at disease onset or who have a family history, Garrod's pads, Peyronie's disease, or plantar foot involvement. Injectable collagenase may reverse some contractures, but this treatment is not yet in widespread clinical use.

This topic was last updated May 2006.