It is a painful condition and, while not life-threatening, it is life-altering. It can force changes in lifestyle, hobbies, even professions, especially during treatment and possibly after treatment, even if the treatment is deemed "successful."

Through some traumatic event or series of events, the lunate -a bone in the wrist- is injured in such a way that the blood supply to the bone is cut off and the bone begins to die.

Only the lunate bone dies, and the condition does not "spread" to other bones or parts of the body.

As the bone dies, pain is generally reported. There may be a period of lesser pain afterward that may last for quite some time, maybe a few days or possibly even years, during which there are no substantial changes to the wrist structure.

Left undiagnosed or untreated, the lunate eventually flattens and collapses and may break into several pieces (fragment). These pieces can shift (displacement) causing pain and/or swelling. For some this is periodic or sporadic, for others it is excruciating and constant, or it can be anything in between.

As the lunate collapses, the other wrist bones (carpals) may migrate. This also causes discomfort in some and pain in others.

The motion of the wrist becomes restricted. It becomes impossible to bend the wrist completely forward (flexion) or backwards (extension). It is not something that can or should be forced; it simply will not go.

Strength is also gradually lost in the hand.

In the latter stages, generalized arthritis sets in.

As this is a Rare Disease, little is known about its cause or treatment.

It is believed that a difference in the lengths of the arm bones (the radius and ulna), known as Ulnar Variation --generally this is a negative ulnar variance, which means the ulna is shorter than the radius by a few millimeters-- is a predisposing factor. Because the bones are asymmetrical, greater "load" or stress is put on the lunate making it more susceptible to this condition. Especially in people with ulnar variance, it is possible to have this condition in both wrists (bilaterally).

A second predisposing factor would be a variation in the blood supply to the lunate itself. Normally there are multiple vessels supplying blood to the lunate, and an injury to one of them would be inconsequential, but some people were born with only one vessel to the lunate. An injury to that vessel could lead to Avascular Necrosis, which is to say, Kienbock's Disease.

Other possible causes are frequent, repetitive strains or a single trauma to the lunate such as a fracture, or abnormalities of the blood's clotting process (hypercoagulability or hypofibrinolysis).

A person is usually diagnosed when he has been in some pain for a while and has a doctor x-ray the wrist. Other times there may be a more-or-less sudden burst of pain that sends him to the doctor.

While an x-ray is adequate for diagnosing and staging the condition, an MRI is often ordered for a more complete look at the joint.

Every case of KD is different. No two joints will progress in exactly the same way or on the same schedule, but there are significant commonalities.

It is not contagious in any way.

Possibly the single most important thing that can be said to a person who is suffering from this condition is that it will get better. You will not have to live the rest of your days at this level of pain. Treatments are available.

As always, external links are prone to technical difficulties outside the control of DarkerBlue and may be removed at any time or for any reason. Bookmark and\or print information that is important to you.

For the purpose of this site, generalities are more important than the sort of full disclosure one would get from medical research, doctors, or the support group on Yahoo!. One of my aims is to point people toward joining the group where those types of details can be explored. At the very least, I hope to spawn better discussions between patients and their doctors, something best accomplished with generalities that inspire questions rather than details which may be interpreted as answers in and of themselves.

Be aware that this site was not written by nor intended to replace doctors. I don't think that a sane, intelligent person would act specifically and solely on the information presented in these pages, but in a litigious society, one must CYA at all times.

And finally, a note on external links. As the Internet is a fluid entity, I am quite reluctant to link external sites other than ones I know to have been around for many years and which I feel will be around for many more. As time allows, most of the external links from this site, aside from those on the Links page, will disappear as I format the information either myself or with the generous help of others. (In other words, bookmark 'em if you want 'em.)
The links to the Kienbock Disease Information Center will remain, as it is a premier site for information not otherwise covered here, has an excellent reputation, and is unlikely to disappear without ample warning and fanfare.

Thanks go out to all who have assisted with this endeavor. Thanks to Angela, the pioneer of Kienbock's Disease on the web, without whom we would have nowhere to turn.
An extra special thanks to Keith, without whom these pages would read like alien shorthand. --srhd