These dislocations usually occur when great force is applied to the wrist and it is bent backward.
The wrist and hand are painful and may look misshapen, and people cannot move them normally.
Symptoms and the circumstances of the injury suggest the diagnosis, but doctors take x-rays to confirm it.
Doctors manipulate the bones back in place without making an incision, apply a splint, and refer people to an orthopedist because surgery is often needed.
(See also Overview of Dislocations.)
The carpal (wrist) bones are located at the base of the hand, between the forearm bones (radius and ulna) and the long metacarpal bones of the hand. There are eight small carpal bones.
Two of the carpal bones are commonly dislocated:
Dislocation of the capitate is called a perilunate dislocation. Perilunate dislocations are more common than lunate dislocations.
These dislocations result from great force that causes the wrist to bend backward, usually a fall on an outstretched hand or an injury in a car crash.
When one of these bones is dislocated, the wrist and palm of the hand are painful. People cannot move the wrist and hand normally. The wrist usually looks misshapen, and the hand swells.
The fingers may tingle and feel numb because the dislocated bone puts pressure on the carpal tunnel (a narrow passageway of fibrous tissue) and the nerves and blood vessels it contains (causing carpal tunnel syndrome). The blood supply to bones in the wrist may be reduced or disrupted, and bone tissue may die. Over time, the wrist joint may deteriorate, causing disabling arthritis.
Prompt diagnosis and treatment of wrist dislocations can help reduce the risk of complications, such as arthritis and death of bone tissue.
People should go to an emergency department if they think that they have dislocated these bones.
People can wait up to a day before deciding whether to call the doctor if the wrist looks and moves normally and if pain can be controlled with over-the-counter drugs. However, if symptoms last more than a day, they should see a doctor.
Doctors suspect perilunate and lunate dislocations based on symptoms and the circumstances of the injury. X-rays are taken to confirm the diagnosis.
Doctors manipulate the wrist bones back in place, without making an incision (called closed reduction). Then a splint is applied to immobilize the wrist and elbow. Usually doctors also immediately refer people to an orthopedist.
Most perilunate and lunate dislocations must be surgically repaired because people have better use of the hand after surgical repair.
Recovery typically takes months.