MP Joint
Arthritis
What is
it?
The knuckle joints in the fingers act as
hinges between the long bones in the hand
and the smaller bones in the fingers. These
joints are called metacarpophalangeal joints
or MP joints of the hand. The MP joints are
important to the hand for gripping and
holding things. Pain and deformity in the
knuckle joints of the fingers are common in
rheumatoid arthritis. This pain and
deformity may be caused by trauma, gout,
psoriasis, or other diseases. Diseases such
as those mentioned can injure the MP joints
by ruining the structures and muscles that
move the joint, or by destroying the surface
of the joint causing pain and deformity in
the knuckle.
Signs
and symptoms.
Difficulty in using the hand for daily
activities (holding or gripping a cup, tool,
or eating utensils for example) is the most
common complaint of patients with MP joint
disease. These problems in using the hand
may be due to deformity, pain, or both. Many
patients notice their fingers slowly
drifting (leaning) to the little finger side
of their hand. Daily activities may become
more difficult with time.
What
causes it?
There can be many reasons for these symptoms
to occur. The ligaments that hold the joint
in place can be loosened by the disease,
causing the joint to slip out of place and
eventually dislocate. The tendons at the top
of the joint may slip out of place and lose
their ability to straighten the fingers.
Treatment.
Treating the symptoms can sometimes be done
without surgery. Medication, splinting,
changes in daily activity, and injections of
anti-inflammatory medicine may be
recommended by your hand surgeon in the
early stages of MP joint disease. If these
forms of non-surgical treatment do not work,
surgery may be needed.
Some advanced
cases of MP joint disease may need surgery.
Two types of surgery are commonly performed.
The first is generally done in less severe
cases and is called synovectomy or
soft-tissue replacement. If the tendons have
slipped out of place, they are put back into
place over the knuckle joint. If the small
muscles of the fingers are causing the
fingers to lean toward the small fingers,
the muscles are operated on to stop the
fingers from being pulled toward the little
finger. The second type of surgery is joint
replacement and is generally used on more
severe cases of MP joint disease. The
diseased metacarpophalangeal joint is
replaced with an artificial joint.
Complications with this type of surgery may
happen. Infection is possible or the
artificial joint may eventually break or
wear down. There is a possibility that a
second replacement of the joint or fusion of
the joint may be recommended in later years.
The goals of
treatment are pain relief and restored
motion to the fingers. Your hand surgeon can
advise you on the best treatment for your
situation.
Rehabilitation.
Rehabilitation following joint replacement
under the close supervision of your hand
surgeon is as important as the surgery. The
hand is usually immobilized for several days
following surgery. A therapy program,
consisting of exercises and special splints,
usually starts the first week after surgery
and continues for four to six weeks. In some
cases the splinting portion of the program
is continued for a longer period of time.
Figure 1
Loss of position of tendons on top of MP
joint result in loss of ability to
straighten fingers and the drift of fingers
toward little finger-side of the hand.
Figure 2
With joint replacement an artificial joint
is placed between the bone ends and tendons
are repositioned. This procedure allows the
fingers to straighten and the drift is
corrected.
Copyright © American
Society for Surgery of the Hand 2001
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