KIENBOCK’S DISEASE

Kienbock’s disease is a condition where the blood supply to the lunate (one of the small bones of the wrist), is interrupted. Bone requires a regular blood supply for nourishment in order to survive. If the blood supply is halted, the bone can die. This bone death is called osteonecrosis. Damage to the lunate can cause a stiff painful wrist and, over time, can lead to arthritis. The goals for treating Kienbock’s disease are to relieve the pressure on the lunate and to attempt to restore blood flow within the bone.

The exact cause of this disease is unknown but trauma, like a fall or direct blow to the wrist can disrupt the blood flow to the bone. You also may only have one blood vessel that supplies blood to the lunate. Most people have two but with only one, the blood flow to the bone is slowed down. Also, if the two forearm bones are different lengths, this can put extra pressure on the lunate during wrist motion which can lead to Kienbock’s disease.

Kienbock’s disease worsens overtime and its severity is characterized in four stages. Stage 1 mimics symptoms similar to a wrist sprain. On an x-ray, the lunate may appear normal or suggest a fracture. This image may not detect a loss in blood supply. The condition progresses to Stage 2 when sclerosis begins. Sclerosis is the process of bone hardening due to lack of blood supply. In an x-ray, the lunate may appear brighter/whiter which is an indication of bone death. There is usually wrist pain along with swelling and tenderness. During Stage 3, the bone will start to collapse and break into pieces, which can cause surrounding bones to also shift positions. There is usually more pain and weakness in the hand as well as limited range of motion. Stage 4 is the last stage of progression, where the other bones surround the lunate also start to deteriorate, leading to wrist arthritis.

Symptoms include a painful wrist that is occasionally swollen. The wrist may also be stiff, limiting range of motion. Grip strength can also decrease, making it difficult to hold onto certain objects. The goals for treating Kienbock’s disease are to relieve the pressure on the lunate and to attempt to restore blood flow within the bone. If caught early, the symptoms can be treated with anti-inflammatory medicines like ibuprofen or aspirin. Limiting wrist motion can also relieve the pressure on the lunate, so splinting or casting may be helpful.

If the condition must be treated surgically, your doctor will make a treatment plan based on how far your disease has progressed and personal needs. One procedure is called revascularization, in which the surgeon can return the blood supply to the lunate. A portion of a blood vessel will be removed from another bone and inserted into the lunate bone as a vascular graft. Joint leveling is another procedure that involves shortening or lengthening one of the forearm bones to match the other. This will reduce the pressure on the lunate and often stops the progression of the disease. If the disease has progressed to Stage 3, your doctor may perform a proximal row carpectomy, where the lunate and the two bones on either side are removed. One other option is an arthrodesis, where the surrounding bones are fused together to make one single bone. Both a proximal row carpectomy and an arthrodesis preserve some wrist motion and relieve pain.