What is Kienbock's disease? What causes Kienbock's disease?

Date: Aug-12-2013Kienbock's disease, also known as avascular necrosis of the lunate, occurs when one of the eight small carpal bones in the wrist - the lunate bone - becomes damaged because its blood supply is lost.

Kienbock's disease is a rare, debilitating disease process that can lead to chronic pain and dysfunction.

In the Journal of Hand Surgery1, avascular necrosis of the lunate is also referred to as "osteonecrosis of the lunate".

Avascular necrosis means death, damage or fracture of bone tissue due to interruption of blood supply.

Without an adequate blood supply, bone death or damage (osteonecrosis) can occur.

Robert Kienböck (1871-1953), an Austrian radiologist and pioneer in the use of x-ray technology for medical diagnosis and therapy, described a disorder in which the lunate bone in the wrist would break down.

Kienböck called the disorder "lunatomalacia". He published his findings in a dissertation titled "Traumatic malacia of the lunate and its consequences" (Über traumatische Malazie des Mondbeins und ihre Folgezuständ). The disorder was later called "Kienbock's disease".

The disease may be spelled "Kienböck's" or "Kienbock's".
The carpal bones in the wrist

In Kienbock's disease one of the carpal bones - the lunate - becomes damaged.

The carpal bones consist of eight wrist bones that connect the hand to the forearm. These bones facilitate flexible positioning of the hand.

The Lunate is one of the 8 bones in the carpus

The lunate bone is crucial for proper movement and support of the joint.

If the lunate bone is damaged, the patient may experience stiffness and pain, and eventually arthritis of the wrist.
What are the signs and symptoms of Kienbock's disease?

According to the National Institutes of Health2, at first, affected people may wonder whether they have sprained their wrist. However, in the case of Kienbock's disease the signs and symptoms do not go away - it is a progressive disease.

Kienbock's disease progresses differently from patient-to-patient. Generally, it develops slowly and subtly over a period of many years.

Initially, the patient might only experience pain and swelling. Later on the mechanics of the wrist become affected. This places abnormal stresses and wear inside the wrist.

According to the American Society for Surgery of the Hand3, Kienbock's diseases has four stages:

Stage 1 - the lunate has lost its blood supply. However, x-rays are unable to detect anything abnormal with the affected bone. There is some pain, possibly some swelling as well, and a risk of fracture.

Stage 2 - x-rays show that the bone is unusually dense. When bone loses its blood supply it hardens.

Stage 3 - the bone starts to shatter (fragments and collapses).

Stage 4 - the lunate has completely collapsed. The other bones next to the lunate have also become damaged and arthritic. No all patients reach this stage.

The following signs and symptoms are common in Kienbock's disease:

swollen wrist
painful wrist
stiffness in the wrist - the range of motion becomes progressively limited
clicking or clunking in the wrist
weaker grip strength
tenderness directly over the lunate bone
difficulty in turning the hand upward
pain when trying to turn the hand upward

What are the causes of Kienbock's disease?

Experts believe Kienbock's disease does not have a single cause, and is the result of multiple factors.

According to Massachusetts General Hospital4, the following factors are associated with a higher risk of developing Kienbock's disease:

Problems with blood supply (arteries). Most of us have two blood vessels supplying blood to the lunate bone. However, in some cases there is just one source.
Problems with blood drainage (veins).
Skeletal variations - possibly the lunate bone has an abnormal shape. The ulna, one of the bones in the forearm may be shorter than normal. If the ulna and radius bones are different lengths there may be extra pressure on the lunate in certain wrist motions - this extra stress could eventually lead to Kienbock's disease.
Some diseases may be linked to a greater risk, including lupus, cerebral palsy, sickle cell anemia and gout. One study found that 9.4% of cerebral palsy patients also had Kienbock's disease5.
Trauma - blood supply may have been affected by a single blow, as in a car accident, or "repeated significant trauma".

There is no compelling evidence suggesting that certain jobs may increase the risk of developing Kienbock's disease

How is Kienbock's disease diagnosed?

Most patients do not come to see a doctor until the symptoms start bothering them. In the majority of cases, this means they have been living with the progressive disease for several months, and even years.

Most patients will initially present with wrist pain.

The doctor will ask questions about the symptoms, medical history, whether there has been any serious trauma, and how long symptoms have been present.

The patient's hand and wrist will be examined.

At first, Kienbock's disease may be difficult to diagnose accurately, because its signs and symptoms are similar to those found in many other conditions, such as wrist sprain and any cause of arthritis.

Even x-ray imaging during Stage 1 of the disease will show an apparently normal lunate bone.

Magnetic Resonance Imaging (MRI) can help the doctor assess the blood supply to the lunate. CT (computed tomography) scanning may be used in later stages to determine the number and sizes of the lunate fragments.

Even if the x-ray does not show any bone abnormality and the doctor does not order further MRI or CT scans, the x-rays will later pick up the signs when the bone starts to harden6 and lose its mineral content.
What are the treatment options for Kienbock's disease?

Treatment usually depends on how early on the disease is diagnosed.
Non-surgical options for Kienbock's disease

Resting the wrist - if it is diagnosed early enough, it might be possible to splint and cast the wrist for several weeks. Resting the wrist increases the likelihood of restoring blood flow to the lunate bone. However, this is only an option during Stage 1.

Anti-inflammatory drugs, such as ibuprofen or aspirin may help manage the symptoms of swelling and pain during the early stages.

Wrist injection with a cortisone type solution may also help symptoms.

Close monitoring of symptoms is important during Stage 1. If OTC (over-the-counter, no prescription required) anti-inflammatory medications start becoming less effective, the doctor may recommend surgery.

A specialized physical therapist can teach the patient "activity modification" - how to use the wrist in a way that is less painful and slows down the progression of the disease.
Surgical procedures for Kienbock's disease

There are several different surgical procedures available for patients with Kienbock's disease. Which one to recommend will depend on several factors. According to the American Academy of Orthopaedic Surgeons7, these options usually depend on:

The stage of the disease
The patient's level of activity
The patient's personal goals
How experienced the surgeon is

External fixator used in orthopaedic surgery
Revascularization - this means either restoring or augmenting the blood supply, which in this case is to the lunate bone.

Revascularization is an option during Stages 1 and 2, before the bone has deteriorated significantly.

The surgeon removes a portion of bone with all its attached blood vessels from another bone and inserts it into the lunate bone.

The portion of bone with that is attached is called a "vascularized graft".

The surgeon may temporarily apply an external fixator to make sure the bones stay in place while they heal. An external fixator is a metal device which is attached to the outside of the wrists, with pins that insert into the bone.

In the video below, Dr. Sergio Rowinski talks about a patient with advanced Kienbock's disease, and the option of vascularized bone graft:

Joint leveling - an option when the two bones - radius and ulna - of the forearm have different lengths. Either bone grafts are applied to lengthen bone, or a section of bone is removed to shorten it.

Joint leveling often stops the disease from progressing by reducing the forces that compress the lunate bone.

Proximal row carpectomy (PRC) - the removal of the lunate bone. An option if the bone is broken into pieces or severely collapsed. The surgeon also removes the two bones on either side of the lunate.

The Hand and Wrist Center of Houston8, Texas, explains the pros and cons of PRC. Advantage - PRC is straightforward surgical procedure. Disadvantage - "The two new bones that rub together do not match and arthritis develops where they make contact."

Fusion - this can be partial or complete fusion. In partial fusion some of the wrist bones are fused together, effectively becoming one solid bone. The aim here is to reduce symptoms of pain and maintain some wrist motion.

If the patient has severe arthritis of the wrist, the doctor may recommend fusing all the bones. The result will be much less pain and better hand function. Even though wrist motion will be completely lost, the patient is still able to rotate the forearm.

When the bones are fused, the result will last for the rest of the patient's life.

Implant arthroplasty - the lunate bone is replaced with a prosthetic replica made of a special, durable, pyrolytic carbon material.

According to the Hand and Wrist Center of Houston, this procedure preserves the normal anatomy of all the others bones.

As this procedure is relatively new in this part of the body, nobody knows what the long-term results of this treatment are.

Some patients may undergo several different procedures during their lifetime. Possibly starting off with casting, then a bone graft, radial shortening, proximal row carpectomy and finally wrist fusion.
What are the complications associated with Kienbock's disease?

If left untreated, the patient will experience progressive deterioration of the wirst, loss of wrist function and increasing pain.

Between Stages 2 and 4 of the disease, grip strength deteriorates by 40%.

Researchers from Shinshu University School of Medicine, Japan, wrote in the Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery9 that "Closed tendon rupture is a well-known complication of Kienbock disease."

Written by Christian Nordqvist

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