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Kienböck DiseaseKienböck disease or Kienböck's disease is a problem in the wrist caused by the loss of blood supply to the lunate. The lunate is one of the eight small bones that make up the “carpal bones” in the wrist (see Figure 1). There are two rows of bones: one closer to the forearm, the “proximal row;” the other closer to the fingers, the “distal row.” The lunate bone is in the center of the proximal row. It is next to the scaphoid bone, which spans the two rows.
Kienböck Disease CausesThere is probably no single cause for loss of blood supply to the lunate. The cause of Kienböck disease
seems to involve multiple factors. These factors include the blood supply (arteries), the blood drainage (veins), and skeletal variations. Skeletal variations associated with Kienböck ’s disease include a shorter length of the ulna, one of the forearm bones, and the shape of the lunate bone itself (see Figure 2). There may be some cases that are associated with diseases like gout, sickle cell anemia, and cerebral palsy. Trauma, either a single event or repeated significant trauma, may affect the blood supply to the lunate. In general, though, Kienbock disease is not felt to be related to occupational hazards. However, the presence of Kienböck disease can affect the treatment and prognosis for traumatic events. |
Figure 1. Normal wrist.
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Figure 2. Wrist with Kienbock's disease and ulna that is short compared to radius.
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Kienböck Disease DiagnosisMost patients with Kienböck disease present with wrist pain. There is usually tenderness directly over the lunate bone. The diagnosis of Kienböck disease is made by history, physical examination, and plain x-rays. Special studies are sometimes also needed to confirm the diagnosis. Probably the most reliable special study to assess the blood supply of the lunate is Magnetic Resonance Imaging, or MRI. CT scanning, specialized CT scanning, and bone scan may also be used.
Kienböck Disease SymptomsThe progression of Kienböck disease is variable and unpredictable. Sometimes the disease may be diagnosed at a very early stage. At this time, there may be only pain and swelling, and normal x-rays. As the disease progresses the x-ray changes in the lunate become more obvious. With further progression, the lunate develops small fractures and the bone fragments and collapses. As collapse occurs, the mechanics of the wrist become changed, which puts abnormal stresses and wear on the joints within the wrist itself. One should be aware that not every case of Kienböck disease progresses through all stages to the severely deteriorated arthritic end-stage.
Kienböck Disease TreatmentLess severe thumb arthritis will usually respond to non-surgical care. Arthritis medication, splinting and limited cortisone injections may help alleviate Treatment options depend upon the severity and stage of the disease. In very early stages, the treatment can be as simple as observation or immobilization. For more advanced stages, surgery is usually considered to try to reduce the load on the lunate bone by lengthening, shortening, or fusing various bones in the forearm or wrist.
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