Deformities of the Hand

Deformities of the Hand

Hand deformities can occur in the bone or joints, or as a result of imbalance of different groups of muscles cause by nerve dysfunction, or due to congenital defects.

Bony deformities are due to fractures of bones that have healed in a crooked or displaced position. One of the commonest bones to be affected is the distal radius, a part of the forearm bone that make up part of the wrist. Caused usually by a fall on outstretched hands in the elderly, this fracture results in a “dinner fork” deformity (the shape of a dinner fork turned to face downwards). If the deformity is not too severe, it usually does not affect function. In some whose movement of the wrist is affected, surgical correction of the bone deformity with bone graft with fixation using titanium plate and screws can be done.

Bony deformities can also affect the fingers as a result of fractures that are not well treated. Deviation and rotation of the finger bone can result in criss-crossing (scissoring) of the fingers, especially when making a fist. These affect function and should be corrected with surgery.

Another common injury that affects the last joint of the fingers results in a “mallet” deformity (where the finger tip becomes bent at the joint, and cannot be straightened by the patient). This is usually successfully treated with a “mallet” splint, although there is usually a slight residual deformity despite treatment.

Deformities of the joints are due to destruction of joint cartilage or ligaments, caused by inflammatory arthritis (such as rheumatoid arthritis or gouty arthritis) or degenerative arthritis (osteoarthritis).

Rheumatoid arthritis destroys the cartilage lining and ligaments of synovial joints. This can affect all the joints of the body, from the spine to the hips and knees, ankles and toes, shoulders and elbows, and wrists and hands. Fortunately, with early treatment by the rheumatologist using better medication, deformities that result are becoming less frequent.

In the hand, this results in the fingers developing “swan neck” and “boutonniere” (button-hole) deformities, and the fingers deviating from the axis of the hand. The thumb may also become crooked.

At the wrist, there may be prominence of the bone (ulnar head), and associated synovitis (inflamed synovial tissue), limitation of motion, and sometimes pain. There may also be related tendon ruptures causing finger drop (inability to straighten the fingers).

Rheumatoid arthritis thus can cause debilitating and unsightly deformities. When function of the hand and wrist becomes affected, surgical correction can be done, with joint replacement combined with ligament and tendon reconstruction.

Deformities caused by osteoarthritis result in pain and stiffness of the joints. Often, the base of the thumb and small joints of the hand are affected. Treatment is by medication and splinting, or surgery with either fusion of the joints or replacement with artificial joints.

Nerve injuries or severe compression result in loss of function of groups of muscles controlled by the affected nerve, causing specific patterns of deformity (e.g., claw deformity). Treatment is targeted at the nerve pathology, which include relieving the nerve compression, and repairing or grafting the injured nerve when necessary. Tendon transfers are often done by using other muscles to take over the function of the muscles controlled by the diseased nerve.

Congenital deformities are less common nowadays, with syndactyly (adjacent fingers joined together) and thumb duplication being the commonest. Surgical reconstruction can be done to get a functional and cosmetically acceptable hand.