Dr Budoff's Blog

Posts Tagged ‘finger arthritis’

Metacarpophlangeal (MP) Joint Replacement

Wednesday, November 23rd, 2011

The metacarpophalangeal (MP) joint is the large joint where the finger attaches to the hand. Arthritis of the MP joint can lead to pain, swelling and stiffness. Nonoperative management includes a steroid injection or two, activity limitation and buddy taping the finger to its neighbor. In patients with rheumatoid arthritis, all of the MP joints can be involved, and the fingers can deviate away from the thumb, making it difficult to use the hand to pick up and pinch objects. Rheumatoid arthritis causes the fingers to angulate, sublux and/or dislocate because it is a systemic disease that destroys not only the joint, but also the ligaments that hold the joint in position.

Once rheumatoid arthritis causes the MP joint to dislocate, joint replacement should be strongly considered. The reason is because following the dislocation, the finger starts to drift up into the palm of the hand. This causes the soft tissues to shorten. Then, when MP joint replacement is finally performed, the finger cannot be brought out to length. At this point, in order place the new joint, a significant amount of bone needs to be removed from the metacarpal bone of the hand. So now the MP joint replacement can no longer be placed in the wide area at the end of the bone. It now must be placed in the narrow shaft of the bone (think of how a dog bone in wider on either end than in the middle). Placing an MP joint replacement in the narrow shaft doesn’t provide as much stability as the wider bone ends do, predisposing to complications.

If non-operative management fails, MP joint replacement is an effective surgical option. Patients without rheumatoid arthritis usually have good tendons and ligaments, and can therefore benefit from the newer total joint replacements now available. These newer MP joint replacements are made of metal and polyethylene (a very tough plastic-like material). Each side of the joint is resurfaced by a separate piece, for a total of two pieces. These replacements are made of the same materials that hip, knee and shoulder replacements are made out of, and are believed to last longer and provide better function than the older single-piece hinged silastic (a rubbery material) joint replacements.

If the ligaments have been compromised, which is almost always the case with rheumatoid arthritis, than the newer type of total joint replacement cannot be used, because there are no ligaments to stabilize the two separate pieces. The older hinged silastic replacement must be used, as these single-piece joint replacements provide their own stability to the joint. These silastic implansts work well, but will eventually break after a number of years. Having said that, good function often remains even after they break; broken silastic joints don’t necessarily have to be replaced.

Both types of replacement provide an average of about 50% of normal motion. However, that amount of MP joint motion is still very functional. Even though it’s not full motion, having 50% of pain-free motion is almost always better than having motion that causes pain, as when a joint hurts its function is usually significantly compromised.

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Proximal Interphalangeal (PIP) Joint Replacement

Tuesday, August 2nd, 2011

The proximal interphalangeal joint is the middle joint of the finger. Injuries to the proximal interphalangeal joint often lead to arthritis. The treatment of proximal interphalangeal joint arthritis starts with buddy taping of the finger to its neighboring digit and a steroid injection into the proximal interphalangeal joint. If significant proximal interphalangeal joint pain continues then the options for treatment are usually either fusion or replacement.

The proximal interphalangeal joint of the index finger is best fused. The index finger is used for pinch. When the index finger opposes the thumb to create power during pinch, this creates a significant sideways stress on the proximal interphalangeal joint. Current proximal interphalangeal joint replacements simply cannot handle this sideways stress, and will become unstable. On the other hand, fusion leads to a stiff but pain-free and stable platform for pinching. The loss of proximal interphalangeal joint motion is not a significant problem for the index finger.

Because the middle, ring and small fingers are used for grasp, motion of the proximal interphalangeal joint of these digits is important. For that reason, proximal interphalangeal joint replacement may be considered. As for most joint replacements, they have less problems as the patient’s age increases. The reason for this is because joint replacements have a limited ‘life expectancy’, and do not last as long in younger, higher demand individuals. Having said that, the newer joint replacements may be better suited for younger, higher demand individuals, within reason.

Proximal interphalangeal joint replacement is performed as an outpatient surgery. The newer metal and polyethylene (a fancy plastic) replacements usually work better than the pyrocarbon implants that were popular a few years back. An example of the newer (SR-PIP) joint implant can be seen at www.totalsmallbone.com/us/products/hand/sr_pip.php4

After proximal interphalangeal joint replacement, motion is started within a few days after surgery with hand therapy. Ultimate motion is about 50% of normal, about 60°. It is unclear how long the newer proximal interphalangeal joint replacements will last.

Unfortunately, these newer unlinked proximal interphalangeal joint replacements are not appropriate for patients with advanced rheumatoid arthritis. Rheumatoid arthritis is a much rarer inflammatory condition than the typical osteoarthritis (wear and tear) that is much more common. If you’re not sure what type of arthritis you have, unless a rheumatologist (arthritis expert) has formally diagnosed you with rheumatoid arthritis, you most probably have simple osteoarthritis or a similar condition. People with rheumatoid arthritis have poor ligaments. Because of this, unlinked replacements, such as the SR-PIP, will become unstable. In cases of rheumatoid arthritis, one-piece linked silastic (a type of rubbery plastic) replacements provide some intrinsic stability and are better options. The post-operative therapy is the same. In cases of rheumatoid arthritis, motion is limited more by the conditions of the finger’s tendons than the joint replacement itself.

So if you are suffering with proximal interphalangeal joint arthritis, there are now better treatment options than were previously available. Most patients are very happy with the pain relief and function afforded by these newer implants.

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Mucous Cysts

Sunday, August 1st, 2010

I recently wrote an article on mucous cysts for the Journal of Hand Surgery. These are a very common cause of finger masses. Mucous cysts are actually ganglion cysts of the small joint of the finger closest to the tip.

Much like ganglion cysts around the wrist (please see my last blog for more information on these), I initially treat mucous cysts by aspirating the fluid inside them. Please don’t try this yourself. The cyst connects to the underlying joint, and if an infection occurs it can spread to the underlying joint, causing a serious problem. Injecting steroids has not been shown to increase the cure rate, and may predispose to an infection.

Unfortunately, 30-70% (approximately half) of the mucous cysts return following aspiration. As these are just hernations of joint fluid, usually from an arthritic joint, they are benign and can often be observed without further treatment.

However, if pain persists or the skin starts to thin, it is very reasonable to have the cyst surgically excised. Thinned skin may make the underlying joint more susceptible to infection. If the skin thins enough, a local flap (soft tissue rearrangement) may become necessary. Many people don’t like the way the cyst looks and desire to have them removed. In addition, the cysts can cause a nail deformity. Removing the cyst can improve or resolve the nail deformity in 60-100%, depending on how long it has been present.

In order to permanently remove the cyst, the underlying joint must be addressed. Many dermatologists and non-hand surgeons often just try to just cut out the cyst or freeze it. That doesn’t usually work too well and recurrences are common follow these inadequate techniques. As for wrist ganglions, the balloon around the joint (the joint capsule) must have a section removed to prevent reformation of the one-way valve that causes these cysts in the first place (please see previous blog). In addition, the bone spurs must often be partially removed to allow a larger open space to prevent rescarring of the tissues around the joint with the recreation of a one-way valve and a recurrence of the cyst. The surgery should be performed by a fellowship-trained hand surgeon, as injury to the tendons, ligaments, and/or nail bed about the joint, with resultant deformity, may occur when surgery in this area is performed by those less well-versed in the anatomy and techniques of hand surgery.

The surgery can be performed under local anesthesia. The dressing can be removed after one week and most activities resumed, including getting the wound wet. However, the finger should not be submerged under water for two weeks. Patients should be aware that at least part of the pain my be due to the underlying joint arthritis, and that removing the cyst won’t cure that part of the pain.

If the skin is very thinned, a flap may be required to provide adequate soft tissue coverage over the joint. This requires rearranging some of the skin and underlying fat on top of the finger, but can also be performed under local anesthesia. Fortunately, this works very well and doesn’t slow down rehabilitation very much.

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