What is Kienbock's Disease?
Kienbock's disease is a condition caused by the disruption of blood flow to the Lunatum bone, one of the eight bones located in the wrist joint. There are two rows of bones in the wrist: one is the "proximal row" closer to the forearm and the other is the "distal row" closer to the fingers. The Lunatum bone is located in the center of the proximal row, next to the scaphoid bone that covers both rows.
What Causes Kienbock's Disease?
As mentioned earlier, the disruption of blood flow to the Lunatum bone is the cause of Kienbock's disease, and there is probably no single cause for this disruption. The cause of Kienbock's disease encompasses many factors. Some of these factors include damage to the vessels that deliver clean blood to the bone (arteries) or the vessels that carry used blood away from the bone (vein vessels) or some skeletal variations.
Skeletal variations associated with Kienbock's disease include:
- Short ulna bone (one of the two bones in the forearm)
- Abnormality in the shape of the lunate bone itself.
Some cases associated with diseases such as Gaucher's disease and cerebral palsy have also been reported.
A single serious injury or repeated trauma (for workers who have to use impact devices) can affect the blood flow to the lunate bone. Generally, however, it is not thought that Kienbock's disease is associated with occupational hazards.
What are the Symptoms of Kienbock's Disease?
Most patients with Kienbock's disease have pain in the wrist.
There is usually sensitivity directly over the lunate bone.
How is Kienbock's Disease Diagnosed?
Kienbock's disease is diagnosed through history, physical examination, and X-rays. Sometimes special studies are needed to confirm the diagnosis. Magnetic Resonance Imaging (MRI) is the most reliable method to evaluate the blood source of the lunate. Computed Tomography (CT) is also used.
What is the Natural Course of Kienbock's Disease?
The progression of Kienbock's disease is variable and difficult to predict. Sometimes the disease can be diagnosed at an early stage. At this stage, there may only be pain and swelling and the X-ray image may be normal. As the disease progresses, changes in the lunate bone become evident on the X-ray. With further progression, small fractures occur in the lunate bone and bone fragments and collapses occur. As the collapse occurs, the mechanics of the wrist changes, causing abnormal strains and wear on the joints within the wrist. Kienbock's disease varies from patient to patient, and it is important to know that not every case will severely worsen and progress to the final stage of cartilage damage in the wrist joint.
What are the Treatment Options for Kienbock's Disease?
Treatment options depend on the severity and stage of the disease. In very early stages, treatment may be as simple as observation or stabilizing the wrist with a half-cast splint.
In more advanced stages, surgery typically aims to reduce the load on the lunate bone by lengthening, shortening, or fusing various bones in the forearm or wrist. Sometimes the lunate bone may require bone grafting or removal. If the disease has progressed significantly and the pain is severe and affecting the patient's daily life, wrist arthrodesis (freezing the wrist joint) may be the preferred treatment.
The results and treatment of Kienbock's disease vary significantly depending on the severity of involvement and whether the disease is progressing or not. The course of the disease and response to treatment will take several months. Sometimes various forms of treatment and even multiple surgeries may be required.
