Kienbock’s disease is a rare bone disorder that affects the lunate, one of your eight wrist bones. The disorder prevents the lunate bone from receiving the necessary amount of blood supply. This lack of blood leads to the death of the bone, also known as avascular necrosis of the lunate.
The lunate is the central bone in your wrist that supports your wrist joint and aids in its movement. Kienbock’s disease can limit wrist movement and can cause pain, injury, or swelling in your wrist. It’s rarely seen in both wrists and most commonly affects men between ages 20 and 40.
What Causes Kienbock’s Disease?
Many factors can lead to the lessening of blood supply to the lunate bone. Some causes of Kienbock's disease include:
- Trauma. Trauma to the wrist due to accidents, like a slip or a fall, can cause injury or swelling.
- Uneven bones in your forearm. You have two bones in your forearm called the ulna and the radius. If your ulna is shorter than your radius bone, it can put pressure on your wrist and increase your risk of developing Kienbock’s disease.
- Irregular lunate bone. If the shape of your lunate bone is slightly irregular, you may develop Kienbock’s disease.
- Underlying medical conditions. Kienbock’s disease is also seen in people who have medical conditions that affect the blood supply. Conditions such as lupus, sickle cell anemia, and cerebral palsy can also cause Kienbock’s disease.
What Are the Stages of Kienbock's Disease?
Stage one. During the first stage of Kienbock’s disease, your lunate bone loses blood supply. This can make your bone weak. You may feel minor symptoms, like pain similar to that of a wrist sprain.
An X-ray may not be able to detect the condition in this early stage, as your bone will appear either normal or slightly weak. An MRI scan can better detect blood flow and can help diagnose Kienbock’s disease in the beginning stages.
Stage two. Due to lack of blood flow, your lunate bone becomes hard. The bone will appear brighter or whiter on X-rays. This shows that the bone is slowly dying. You may feel pain, soreness, and swelling in your wrist.
Stage three. The dead bone starts to slip, collapse, and break into small parts within your wrist. This can affect other bones in your wrist, causing them to shift their position. You may experience growing pain, weak grip strength, and limited wrist movement.
Stage four. In this stage, your bone collapses. This can injure the other bones or the connective tissue of your wrist.
Kienbock’s disease progresses slowly. You may have the condition for several months to a few years before experiencing symptoms.
What Are the Symptoms of Kienbock’s Disease?
Symptoms of this bone disorder include:
- Wrist pain
- Tenderness over the lunate bone
- Limited movement
- Wrist joint stiffness
- Decreased grip strength
How Is Kienbock’s Disease Diagnosed?
Your doctor will diagnose Kienbock’s disease by checking your medical history and doing a physical examination. They may suggest X-rays, but keep in mind that X-rays may not be able to detect the disease in the early stages. In order to get a better look, you may have to get an MRI or CT scan to check the blood supply to the lunate bone.
How Is Kienbock’s Disease Treated?
Based on the stage of the disorder, Kienbock's disease treatment options vary. The following treatments are used:
Medication. In the early stages, symptoms like pain and swelling can be controlled using anti-inflammatory medicines, such as aspirin or ibuprofen.
Immobilization. Immobilizing your wrist with a plaster cast for 2 to 3 weeks can relieve the pressure on the lunate bone.
Surgery. If the disease progresses and symptoms persist, you may have to have surgery.
The following surgical options are available to treat Kienbock’s disease:
- Revascularization. A common surgery done to treat early-stage Kienbock’s disease, revascularization consists of the transportation of blood cells from other parts of your wrist directly to your lunate. This restores the blood supply to the bone.
- Joint leveling. Your surgeon will perform this procedure to level out the uneven bones in your forearm. They will lengthen or shorten your radius or ulna so that they don’t apply pressure on your wrist.
- Lunate excision. This involves the full removal of the lunate bone or removal of the pieces of bone from your wrist. The surgeon may add an artificial bone to replace your lunate.
- Intercarpal fusion. In the late stages of the disorder, this surgery is performed to join the lunate to a neighboring wrist bone. It can be done along with revascularization to restore blood flow to the lunate bone.
- Proximal row carpectomy. In the last stage of Kienbock’s disease, you may get wrist arthritis because of the broken lunate bone. This surgery involves the removal of four of the eight bones in your wrist. It makes room for your wrist to move.
After surgery for Kienbock’s disease, your doctor will ask you to wear a splint for 3 to 4 months. You’ll have to visit the surgeon for a follow-up to ensure that the bone is healing. Once your wrist heals, you’ll have to start physical therapy for a few months to regain wrist strength and movement. When the pain goes away, you can resume daily activities.