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Wrist Disease
Kienbocks
Wrist Disease
Introduction
Kienbock's disease, properly spelled Kienböck's,
is also known as Avascular Necrosis of the Lunate, or
Lunatomalacia. It was first described by Viennese radiologist
Dr. Robert Kienbock in 1910. Kienbock's 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.
Stage 3 of Kienbocks Disease showing
collapse and possible fragmentation of the lunate bone
Cause
Doctors have not determined exactly what causes Kienbock's
disease. A number of factors seem to be involved. Usually
the patient has injured the wrist. The injury may be
a single incident, such as a sprain, or a repetitive
trauma. But the injury alone does not seem to cause
the disease.
The way that blood vessels supply the lunate is thought
to play a role in Kienbock's disease. Some bones in
the body simply have fewer blood vessels that bring
in blood. The lunate is one of those bones. A bone with
a limited blood supply may be more at risk of developing
the disease after an injury. The reduced blood supply
might be the result of a previous injury to the blood
vessels.
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.
Symptoms
- A painful and sometime swollen wrist
- Pain or difficulty in turning the hand upward
- Tenderness directly over the wrist bone
- Wrist stiffness
4 stages of progression:
Stage 1: Symptoms similar to that of wrist sprain.
Stage 2: The lunate bone begins to harden. The patient
may complain of persistent pain, swelling and tenderness.
Stage 3: The dead bone begins to collapse and break
into small pieces The patient will complain of intense
pain.
Stage 4: The surfaces of the adjoining bones are affected
which often results in arthritis.
Treatment
Treatment is not well-defined, because the cause is
not well known. Kienbocks is very difficult to diagnose
as the initial symptoms are so similar to a sprained
wrist. Even x-rays appear normal at the beginning but
the primary goal of treatment should be to help relieve
pressure on the lunate and assist blood flow.
Medical therapy: Treatment is primarily directed by
the level of symptoms. The primary methods of non-operative
treatment are immobilization and anti-inflammatory medications.
Because our best understanding of the disease is that
it is related to loss of blood supply to the lunate,
and because we know some patients can be cured if we
can just avoid trauma and collapse, this is our first
choice in the earlier stages. Younger patients tend
to have a better ability to re-establish blood flow
to various areas, so in a very young patient, we almost
always start with this approach, especially if the disease
is early, in hopes of allowing revascularization of
the lunate and prevention of disease progression.
Surgical therapy: Surgery is reserved for more advanced
disease. Although there is no cure, there are several
surgical options for treating the more advanced stages
of Kienböck’s disease. The right procedure
for you will depend on several factors, including disease
progression, your personal activity levels and goals.
The two most important pieces of information are the
stage of your disease and the presence or absence of
ulnar variance (the length of the ulna to the length
of the radius). Possible surgical procedures include:
- Excision of dead lunate
- Joint-leveling procedures (shortening the longer
bone or lengthening the shorter bone)
- Intercarpal fusions (remove some of the wrist bone
joints and make them grow together into one or more
bigger bones)
- Revascularization (returning the blood supply to
the bone)
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