Diseases & Conditions
Kienböck's disease is a condition where the blood supply to one of the small bones in the wrist, the lunate, is interrupted. The lunate is a carpal bone.
Bone is living tissue that requires a regular supply of blood for nourishment. If the blood supply to a bone stops, the bone or parts of the bone can die. This is called osteonecrosis.
A loss of blood supply to the lunate causes the bone to lose its structural support, and it will collapse, causing a painful, stiff wrist. Over time, these changes can lead to arthritis of the surrounding bones in the wrist.
The cause of Kienböck's disease is not known. There may be one or more factors that cause a disruption of blood flow to the bone.
Many people with Kienböck's disease think they have a sprained wrist at first. They may have experienced some form of trauma to the wrist, such as a fall. This type of trauma can injure the blood vessels that supply the lunate.
Some things may put you more at risk for the disease. For instance:
- Some people may have fewer blood vessels that supply the lunate; most people have two arteries that supply blood to the lunate, but in some people there is only one source.
- Forces acting on the lunate may be different depending on the relative lengths of the two bones in the forearm (the radius and the ulna). If the radius and ulna are different lengths, extra pressure can be put on the lunate during some wrist motions and when pressure is applied to the wrist during activity, such as when doing a push-up. Over time, this extra pressure may lead to a compromise of blood flow to the lunate and cause Kienböck's disease.
The most common symptoms of Kienböck's disease include:
- Wrist pain
- Wrist swelling
- Limited range of motion in the affected wrist/wrist stiffness)
- Decreased grip strength
- Tenderness directly over the bone (on the top of the hand at about the middle of the wrist)
Kienböck's disease is a condition that progresses slowly, often over many months or years. Many people do not decide to see a doctor until they have lived with symptoms for several months, or perhaps longer.
During your first appointment, your doctor will discuss your symptoms and medical history, then examine your hand and wrist.
In its early stages, Kienböck's disease may be difficult for your doctor to diagnose because the symptoms are so similar to those of a sprained wrist. Imaging tests, such as X-rays and magnetic resonance imaging (MRI) scans, are used to make a diagnosis of Kienböck's disease. Even with special imaging studies, however, the early diagnosis of Kienböck's disease is not always clear or able to be confirmed.
Kienböck's disease progresses through four stages of severity. If you are diagnosed with Kienböck's disease, your doctor will plan your treatment based on several factors, most important, the stage of your progression.
- During the first stage of the disease, the symptoms are similar to those of a wrist sprain.
- Although the blood supply to the lunate has been disrupted, X-rays may still appear normal or suggest a possible fracture.
- An MRI scan can better detect the effects of abnormal blood flow and is helpful in making the diagnosis in this early stage.
- The lunate bone begins to harden due to the lack of blood supply during Stage 2. This hardening process is called sclerosis and is an abnormal increase in bone density.
- The lunate will appear brighter or whiter in areas on X-rays, which indicates that the bone is more dense.
- To better assess the condition of the lunate, your doctor may order either an MRI scan or a computed tomography (CT) scan.
- The most common symptoms during this stage include wrist swelling and intermittent pain, particularly when force is applied to the wrist, such as with weightbearing.
- In Stage 3, the necrotic or dead lunate bone begins to collapse and fragment (break) into pieces. As the bone begins to collapse or break apart, the surrounding bones become affected and may begin to shift position.
- During this stage, patients typically experience increasing pain, grip weakness in gripping, and limited wrist motion.
- If the condition progresses to Stage 4, the surfaces of the bones surrounding the lunate also deteriorate, and the wrist may become arthritic. Arthritis involves a loss of the articular cartilage or joint surface.
Although there is no complete cure for Kienböck's disease, there are several nonsurgical and surgical options for treating it. Treatment strategies consider the stage of the condition and the patient's symptoms.
The goals of treatment are to relieve the pressure on the lunate and to try to restore blood flow within the bone.
In the very early stage of the disease:
- Pain and swelling may be managed with anti-inflammatory medications, such as aspirin or ibuprofen.
- Immobilizing your wrist for a period of time can help relieve pressure on the lunate.
- Your doctor may recommend a short period of splinting or casting.
It is important to monitor any changes in your symptoms during the early stage of Kienböck's disease. If the pain is not relieved with simple treatments or it returns, your doctor may recommend surgery.
Occasionally, if the diagnosis is not certain, your doctor may recommend repeating the imaging studies for your wrist after this period of initial treatment.
There are several surgical options for treating Kienböck's disease. The choice of procedure will depend on several factors, in particular how far the disease has progressed.
The key factors in decision-making include:
- The presence or absence of lunate collapse or fragmentation
- Joint arthritis
Additional factors to consider include:
- The patient's activity level
- The patient's personal goals
- The patient's symptom tolerance
- The surgeon's experience with the procedures
Revascularization. In some cases, it may be possible to restore the blood supply to the lunate bone. This procedure is called revascularization. It is more successful during early phases of the disease — stages 1 and 2 — before the lunate has collapsed or fragmented.
Revascularization involves removing a portion of bone with attached blood vessels from another bone — most often a forearm bone (radius) or an adjacent bone in the hand. This piece of bone with its blood supply is called a vascularized graft. It is moved carefully, preserving the feeder blood vessel, and inserted into the lunate bone.
To help the bones stay in place and to reduce pressure on the lunate bone during healing, an external fixator or a plate may be temporarily applied, spanning the forearm to the hand.
- This external fixator is a metal device that is attached to the outside of the wrist with pins that insert into the bones.
- A plate is placed below the skin directly against the forearm bone (radius), crossing the wrist joint and attaching to the metacarpal bone in the hand.
Both devices can relieve pressure on the lunate while the graft is healing and restoring a blood supply.
Joint leveling. If the two bones of the lower arm are not the same length, a joint leveling procedure may be recommended. Bones can be made longer using bone grafts or shortened by removing a section of the bone. This leveling procedure reduces the forces that compress the lunate and often stops the progression of the disease.
Proximal row carpectomy. If the lunate is severely collapsed or broken into pieces, it can be removed. In this procedure, the two bones on either side of the lunate are also removed. This procedure, called a proximal row carpectomy, will relieve pain while maintaining partial wrist motion.
Fusion (arthrodesis). To reduce pressure on the lunate, nearby wrist bones can be fused together to make one, solid bone. A fusion can be partial, in which just some of the wrist bones are fused together. This procedure relieves pain and retains some wrist motion.
If the disease has progressed to severe arthritis of the wrist, fusing all of the bones of the wrist to the radius will relieve pain and improve hand function. Although all wrist motion is eliminated in a complete fusion, forearm rotation is preserved.
Kienböck's disease varies considerably in its severity, as well as in its rate of progression. Each patient's response to treatment depends on the degree of damage to the lunate and surrounding wrist bones. Some patients may require more than one procedure over time if the disease continues to progress.
Kienböck's disease is a challenging condition to both diagnose and treat. Often, the progression of the disease is slow, and typically the condition is not discovered until the wrist becomes painful or problematic.
Treatment is based on the severity and stage of the condition. The condition of the lunate bone (collapse, fragmentation) and surrounding joint surfaces (arthritis) will determine treatment options.
While you should not expect to ever return to normal wrist function, appropriate treatment gives you the best opportunity for long-term pain relief and preservation of function.
AAOS does not endorse any treatments, procedures, products, or physicians referenced herein. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance should consult his or her orthopaedic surgeon, or locate one in your area through the AAOS Find an Orthopaedist program on this website.