Kienbock’s disease, also known as avascular necrosis of the lunate, is a condition in which the lunate bone, one of eight small bones in the wrist, loses its blood supply, leading to death of the bone. The lunate is a central bone in the wrist that is important for proper movement and support of the joint (Figure 1). It works closely with the two forearm bones (radius and ulna) to help the wrist move.
Damage to the lunate can lead to pain, stiffness, and sometimes arthritis of the wrist if some time has passed. Kienbock’s disease is most common in men between the ages of 20 and 40 and rarely affects both wrists.
There is no single cause of Kienbock’s disease. It can be caused by multiple factors such as:
- Skeletal variations: The ulna can be shorter than the radius, which may cause issues. Or, the shape of the lunate bone may be irregular (see Figure 2).
- Trauma: A single incident or multiple incidents may cause this disease.
- Other medical conditions: Kienbock’s disease can be found more commonly in people who have medical conditions that affect blood supply, and it is also associated with diseases like lupus, sickle cell anemia and cerebral palsy.
SIGNS AND SYMPTOMS
Most patients with Kienbock’s disease have the following symptoms:
- Wrist pain
- Tenderness directly over the lunate bone
- Decreased motion or stiffness of the wrist
The diagnosis of Kienbock’s disease can often be made by reviewing your history, performing a physical examination, and taking x-rays. In early stages of this disease, the x-rays may be normal and other tests are needed to confirm the diagnosis. Most likely, the most reliable test to assess the blood supply of the lunate is Magnetic Resonance Imaging (MRI) (Figure 3). CT scanning, specialized CT scanning and bone scan may also be used.
This is a slow-progressing disease, and patients often have the condition for months or even years before they seek treatment. It can be difficult to diagnose in its earlier stages.
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. Hand therapy does not change the course of the disease; however, it can help to minimize impairment from the disease. Treatment is designed to relieve pain and restore function.
Your hand surgeon will advise you of the best treatment options and explain the risks, benefits and side-effects of various treatments for Kienbock’s disease.
Figure 1: Normal wrist
Figure 2: Wrist with Kienbock’s disease showing an ulna that is shorter than the radius
Figure 3: MRI of a wrist with Kienbock’s disease showing loss of blood supply to the lunate in a patient with a short ulna
© 2016 American Society for Surgery of the Hand