Kienböck 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. While the exact cause of this uncommon disease isn't known, a number of treatment options are available.
In this study, surgeons treating Kienböck Disease investigate the use of a procedure called lunate core decompression. The lunate bone in the wrist is the usual target of Kienböck Disease. Decompression is a surgical technique used to take pressure and load off the bone. The best result is a restoration of blood flow to the area called revascularization.
During the lunate decompression surgery, a small hole is drilled into the center of the bone. After surgery, the drill hole gradually fills with tissue. Sometimes, new bone forms within this area. The procedure may help increase the blood flow to the diseased area of bone and allow new blood vessels to form. Core decompression appears to slow down the disease process. It may even stop the progression of disease.
Before going on to discuss the results of the procedure, the authors reviewed other types of treatment used for this disease. One of those procedures is called joint-leveling. Here's a brief explanation of why joint-leveling is used.
Some experts think that a difference in length between the two bones of the forearm (radius and ulna) adds stress and pressure on the lunate. When the ulna is shorter than the radius, an imbalance of pressure is created in the wrist joint.
Normally, the ulna supports a portion of the force that needs to be transferred from the hand to the forearm. If the ulna is too short, this cannot occur. The lunate is caught between the capitate bone and the radius and must absorb more force when the hand is used for heavy gripping activities. Over time, this extra force may make it more likely for a person to develop Kienböck disease. Chronic repetitive trauma can lead to damage of the arteries supplying blood to the lunate.
A joint-leveling operation either shortens the bone that is too long (the radius) or lengthens the bone that is too short (the ulna). Joint leveling operations include ulnar lengthening and radial shortening osteotomy. But this procedure has come under question because of the many complications associated with it and also because the problem has been successfully treated in other ways.
One of those other treatment approaches is a vascularized bone graft. A piece of bone with its blood supply still intact is removed from one part of the body and transplanted to the area of the lunate. Bone grafts don't always "take" and the bone dies anyway.
That's why this study is so important. Lunate core decompression is a simple procedure that doesn't involve bone graft or removing bone. If successful, this type of surgery could be of real value to patients with early stages of Kienböck Disease.
Results of decompression for 20 patients with early stages of Kienböck Disease were measured using pain, wrist range-of-motion, function, disability, and X-ray images. All measures were taken before surgery and again five years later (after surgery). The results were very favorable for most of the patients. Only two of the 20 patients had a failed result requiring additional surgery.
Three of the patients still reported some tenderness at the wrist but this was much improved from the previous pain. Before surgery, 18 of the 20 patients reported tenderness over the lunate. X-rays showed no change in the alignment of the carpal (wrist) bones meaning that there was no collapse of the bones (something that happens as the disease gets worse). Best of all, there were no complications with the decompression procedure.
The authors concluded that lunate core decompression may be an acceptable and successful (simple) surgical treatment of early stages of Kienböck Disease. It may be possible to avoid the more invasive joint-leveling procedures. Likewise, complications such as nonunion, infection, and ulnar impingement are reduced and possibly even eliminated.
Reference: Saeed Mehrpour, MD, et al. Treatment of Kienböck Disease by Lunate Core Decompression.In The Journal of Hand Surgery. October 2011. Vol. 36-A. No. 10. Pp. 1675-1677.