Keinböck’s disease is a condition affecting one of the small bones of the wrist, the lunate. In this disease, the blood supply to the lunate is blocked. Bones require a constant blood supply in order to survive. Without this blood supply, the bone gradually dies, a condition is known as osteonecrosis. The loss of the blood supply to the lunate seen in Keinböck’s disease can be caused by trauma to the wrist, but often the cause is unknown.
Diagnosis of Keinböck’s disease can be difficult because at first it is often mistaken for a sprained wrist. In the early stages of the disease, even an X-ray may not show bone damage. Symptoms of Keinböck’s include pain and tenderness of the wrist, difficulty in turning over the wrist, decreased grip strength, and stiffness.
There are four stages commonly seen in the disease. In the first stage, symptoms resemble a sprained wrist (tenderness, stiffness, and pain). An MRI may help make a diagnosis, but an X-ray is unlikely to be helpful. In the second stage, the lunate begins to die. In this stage, an X-ray will show a brightening of the bone. A CT scan or MRI may also be helpful in diagnosis. In the third stage, the dead lunate bone begins to break apart. In this stage, you may experience a limited range of motion and continued weakening of grip strength. Further pain, swelling, and tenderness are also common. The breaking apart of the lunate may cause surrounding bones to shift position, further limiting range of motion. In the fourth stage, arthritis occurs as a result of damage to the surface of surrounding bones.
There are several surgical options which may improve the symptoms of Keinböck’s disease. It is possible in some cases to re-supply the lunate with blood by using a bone graft from the lower arm. Other surgeries focus on removing pressure on the lunate, which can halt progression of the disease if caught early. In later-stage cases, it may be necessary to remove the lunate and several surrounding bones. This limits the range of motion in the affected wrist, but will get rid of the pain caused by the disintegrating bone. When the disease has already progressed to arthritis, fusing several of the bones of the wrist may improve pain symptoms. Your surgeon can discuss the best options for your disease course, activity level, and lifestyle.