Kienbock's disease is a condition in which one of the small bones of the wrist loses its blood supply and dies, causing pain and stiffness with wrist motion. In the late stages of the disease, the bone collapses shifting the position of other bones in the wrist. This shifting eventually leads to degenerative changes and osteoarthritis in the joint.
You will experience pain in the wrist and limited wrist movement. Pain may vary from slight discomfort to constant pain. In the early stages there may be pain only during or after heavy activity using the wrist. The pain usually gets slowly worse over many years. The wrist may swell. The area over the back of the wrist near the lunate bone may feel tender. You may not be able to move your wrist as much as normal or grip objects as well.
Kienbock’s usually progresses slowly over many years. To help understand the disease and recommend the best treatment surgeons divide the progression of the disease into four stages:
Stage 1 The bone loses its blood supply and a fracture of the lunate may occur.
Stage 2 The bone hardens (called sclerosis) because of the lack of blood supply.
Stage 3 The dead lunate bone collapses. It may break into several pieces and move out of its normal position.
Stage 4 The surfaces of the nearby wrist bones are damaged, resulting in arthritis of the wrist.
Stage 1 Kienbock's is usually treated using non-surgical treatments. Your surgeon may suggest immobilising the wrist in a cast for up to 3 months. It is possible that the blood supply to the lunate will return and the disease will clear up during this time. If the patient has what's known as transient (meaning short lived) osteonecrosis rather than true Kienbock's disease, the condition may also clear up during this time. Transient osteonecrosis sometimes develops briefly after an injury.
Stage 2 and Stage 3 Kienbock's often requires surgery when immobilising the wrist does not help. Attempts to restore the blood flow to the lunate are most likely to be successful at this point. The procedure to restore blood flow is called Revascularisation. During the operation, the surgeon moves a small section of blood vessels (and also possibly bone) from elsewhere on the patient. The segment is attached to the deteriorating lunate bone. This is done to restore blood flow to the lunate and halt its deterioration. This is a newer procedure to treat Kienbock's disease and is not always successful.
Arthroscopy and fusion uses an arthroscope to operate and makes a small incision over the lunate. The surgeon cleans the area around the lunate and then fuses the lunate to the carpal bone next to it. Bringing an extra blood vessel to revascularise the lunate (described above) is not necessarily a part of the treatment.
Lunate decompression is used at this stage to take some of the pressure off (decompress) the lunate bone. Doing this may allow the bone to heal and revascularise, or it may at least slow the progression of the disease.
Operations to do this include a Radial shortening osteotomy. In this operation, removing a small section of the bone near the wrist shortens the radius bone, allowing the bone to heal together in this shortened position.
Sometimes a capitate shortening (known as the Almquist procedure) is carried out, which shortens a carpal bone on the other side of the lunate. Lunate decompression and capitate shortening are both helpful for reducing the force on the lunate.
Surgeons focus on treating the wrist osteoarthritis that results when the lunate collapses and dies in Stage 4. One surgical option at this stage is Proximal-row carpectomy. Carpectomy means excision (removal) of one or more of the carpal bones. The wrist is made up of two rows of carpal bones, four in each row. The lunate is in the proximal row (the row closest to the forearm). When the lunate has collapsed, but the wrist joint is not terribly arthritic, the four carpal bones of the proximal row may simply be removed. This allows the distal row (the other four bones) to slide down a bit and to begin moving against the forearm bones instead. The wrist joint seems to work pretty well after this procedure. The advantage is that you will still have a reasonable degree of wrist motion, unlike wrist fusion (described below). A proximal row carpectomy is a good solution when you need a flexible wrist more than you need a strong one, such as in someone who plays piano for a living. During this procedure, the surgeon can also take out a section of the nerve that supplies feeling to the wrist joint to reduce wrist pain. This will not affect the feeling in your hand, because it only affects the nerve that goes to the wrist joint itself, below the skin level.
Finally, your surgeon may also suggest a Wrist fusion (arthrodesis of the wrist) when the entire wrist has become arthritic. Fusion is an operation that allows all the bones of the wrist to grow together to form one bone. This makes the wrist stiff. You will not be able to bend the wrist after a fusion. You will be able to turn the wrist palm up and palm down.
A fusion is a good solution when you need a strong wrist more than you need wrist movement, such as someone who does manual labour.
You will be placed in a splint for about 12 weeks after surgery. Your surgeon will x-ray thewrist several times after surgery to make sure that the bones are healing properly. Once your wrist has begun to heal, you can safely begin a rehabilitation programme. After surgery, you may need physiotherapy for 8 to 12 weeks. The first few treatments will focus on controlling the pain and swelling. You will work into doing exercises to help strengthen and stabilise the muscles around the wrist joint. Other exercises are used to improve fine motor control and dexterity of your hand.