Over 100 years ago, Dr. Robert Kienböck, an Austrian radiologist described (and named after himself) a breakdown of the lunate wrist bone. Now known as Kienböck disease, we still don’t know really what causes it or how to best treat it.
Kienböck disease is a condition in which one of the small bones of the wrist (the lunate) 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.
Bone sclerosis (hardening), fracture, collapse, and arthritis are just a few of the things that can happen with this disease. The patient suffers from pain, swelling, loss of motion, and loss of function sometimes leading to disability. Treatment can range from conservative (nonoperative) care to any one of a number of surgical procedures.
In this article, hand surgeons from the Division of Hand Surgery at the Rothman Institute in Philadelphia concentrate on surgical procedures based on staging of the disease. Staging of any disease is a way to classify the patient’s condition based on severity. In the case of Kienböck disease, X-rays are used to determine each patient’s stage. The following is a brief summary of the stages.
decreased signal throughout the bone is seen on MRI.
often present but bone is not collapsed and joint is not narrowed.
stage is divided into two parts. Part A: lunate has collapsed but without loss of joint alignment. Part B: There is lunate collapse plus other bones around the lunate have now shifted causing changes in wrist alignment.
The authors are clear in pointing out that X-ray findings and staging direct treatment but not without consideration for the patient’s symptoms. Some people can have severe symptoms with Stage 1 disease. Others can have no symptoms despite Stage 4 disease. And every possible combination can occur between those two extremes.
Most of the time, Stage 1 disease is treated conservatively with splinting or some other kind of immobilization. This gives the wrist a rest and the bone a chance to heal. If the patient develops Stage 2 or even Stage 3A disease, the focus of treatment is to restore blood supply to the bone and prevent the disease from getting worse.
In these cases, the surgeon has several options to choose from including the old tried and true “traditional” approaches as well as some new treatment procedures. Some of the more traditional methods include pinning the bone in place, taking a piece of bone out of the radius (forearm bone) to help take pressure off the wrist, or shortening one of the other wrist bones to unload the lunate.
One of the newer procedures involves bone grafting (e.g., pedicled bone graft or vascularized bone transfer). This approach amounts to taking bone that still has a good blood supply and using it to help create new and improved circulation to the defected area in the wrist. There are limited long-term studies showing the results of these procedures but early results show no further bone collapse or disease progression.
The surgeon may need to level the joint by removing from (shortening) or adding to (lengthening) bone from the forearm that makes up part of the wrist. The authors review when to use each procedure (and when NOT to use them!). They base their recommendations off the results of other studies’ reports of complications, successes, and safety concerns.
Stage 3B and Stage 4 require a different approach because the lunate bone has collapsed and sometimes the other bones have shifted as a result of the collapse. Choices of surgical treatment for Stage 3B disease include arthrodesis (bone fusion), osteotomy (partial bone removal), or complete excision (removal) of the lunate with soft tissue put in its place (called interposition arthroplasty).
Removing all of the bones in the first row of the wrist (called carpectomy) may be done when the Stage 3 disease process is more severe. But studies show this isn’t an ideal solution as patients often end up having the wrist fused. It is not recommended for anyone under the age of 35.
Stage 4 disease is considered past the point of being able to restore or reconstruct the bone, joint space, or alignment. Arthritis has permanently altered the joint so that treatment is considered more of a salvage approach. In other words, the surgeon does what he or she can to save as much as possible without further destroying the wrist. The hope is to ease the patient’s pain and prevent further progression of disease. In some cases, the nerves to the wrist have to be cut to achieve pain control.
In summary, the authors do a very fine job giving us a broad perspective of Kienböck disease over the last 100 years. They review what we know about causes, anatomy, natural history, and current treatment. X-rays, MRIs, and tables are also provided that summarize stages and treatment of this condition.