Chances are, you probably know someone who's had a knee or hip replacement. Each year, more than 750,000 Americans undergo one of those procedures. But how about a knuckle replacement?

Yes, it's possible to have the tiny joints in your fingers replaced with prostheses to ease the pain and suffering associated with arthritis. And although this type of surgery (known as arthroplasty) is still being perfected and is far less common for knuckles than for knees or hips, it can provide rapid relief to people whose hands are ailing.

"Patients are happy right off the bat," says Arnold-Peter Weiss, MD, a hand surgeon, professor of orthopedics, and associate dean of medicine at Brown University Medical School, in Providence, R.I. "It even surprises me."

The procedure is quick and relatively straightforward, but it's not appropriate for everybody and does carry a risk of complications and failure. Moreover, some experts argue that knuckle replacements have not been studied thoroughly enough to justify their widespread use in arthritis patients. Still, it's a viable option for people in severe pain.
More about arthritis

Is knuckle replacement right for you?
Knuckle replacements have been around since the 1950s. In general, the surgery is used only in people with severe pain or lack of mobility. That typically means arthritis patients whose pain interferes with daily activities and people whose pain isn't alleviated by nonsurgical treatments like finger braces, splints, or anti-inflammatory medications such as Advil or Aleve.

Historically, knuckle replacement was most common in patients with rheumatoid arthritis (which can cause hand deformities), although the procedure is pretty evenly split now between RA and osteoarthritis patients, says Jay Bridgeman, MD, assistant professor of hand and microvascular surgery at the Penn State College of Medicine. Improvements in rheumatoid arthritis medications over the years have reduced the number of surgeries that are necessary, he explains.

The purpose of the surgery is to remove the damaged cartilage, tissue, and bone, and insert an artificial replacement joint in the remaining healthy bone. Although the new joint doesn't entirely restore mobility, it can almost completely eliminate pain and return the hands to their normal shape.

Dr. Weiss, who practices at Rhode Island Hospital, says he performs anywhere from one to three knuckle-replacement surgeries each month, usually on the knuckles at the base of the fingers (known as the metacarpophalangeal joints). Osteoarthritis patients typically get one or two of these joints done at once, while rheumatoid arthritis patients often have all four of them "go bad" at the same time, he says.

[ pagebreak ]Nortin Hadler, MD, a rheumatologist and professor of medicine at the University of North Carolina at Chapel Hill, says he doesn't recommend the procedure to as many patients as he once did. "Now rheumatologists are more aggressive at treating the diseases—because we can be," he says. "The medications are better and the disease is milder—partly because of earlier diagnosis—and we are less enthusiastic about the surgery."

The effectiveness of knuckle replacement is a matter of ongoing debate among hand surgeons and rheumatologists. Surgeons, not surprisingly, are more likely to believe it's a worthwhile procedure. In a 2003 survey, 83% of hand surgeons said that knuckle replacement "always" or "usually" improves hand function, compared with just 34% of rheumatologists. Likewise, 92% of surgeons and 60% of rheumatologists replied that the surgery always or usually relieves pain.

What are the options?
Depending on the joint that needs to be repaired and the finger in which it is located, there are various options for treatment. These include a total knuckle replacement, fusing the existing joint together (known as arthrodesis), or cleaning away damaged cartilage and bone.

The small knuckles at the tip of the finger aren't usually replaced, as studies have shown that failure and poor longevity can be a problem with this joint. Fusion is typically effective at relieving pain in these knuckles, though it does not restore mobility, Dr. Bridgeman says.

By contrast, the middle knuckles are usually replaced, particularly those on the ring and middle finger, which need to retain flexibility for gripping. (The exception is the middle knuckle on the index finger. Fusion is generally preferred because this joint gets heavy use and prosthetics tend to wear out too quickly.)

The bottom knuckles, where the fingers meet the hand, are the largest and are almost always replaced, especially in rheumatoid arthritis patients.

Several types of replacement knuckles exist. The most widely used versions—including a model patented by Dr. Weiss—are made from flexible silicone rubber and act like spacers between the remaining healthy bones. Although these implants allow flexibility, they tend to break and slip.

To avoid these complications, researchers are trying to make better metal-and-plastic replacement joints that work like a ball-and-socket—like most prosthetic knees and hips—so they fit in the joint more tightly.

Regardless of which knuckle is being replaced or what device is used, the surgery is a quick outpatient procedure. Each knuckle takes about 30 minutes, Dr. Weiss estimates. The procedure is covered by Medicare, which reimburses doctors about $600 per joint, although the full cost of the procedure may vary widely.
Next Page: Recovery time

[ pagebreak ]Recovery time
The procedure carries a small possibility of complications. As with any surgery, there is a slight risk of infection, and cases of enlarged lymph nodes (lymphadenopathy) have been reported.

In most cases, patients typically feel about 90% better almost immediately, Dr. Weiss says. But Dr. Hadler says that the recovery is neither simple nor brief.

After surgery, patients are required to undergo physical therapy, which can last anywhere from six to 12 weeks. Rheumatoid arthritis patients tend to need more rehab than those with osteoarthritis, because they usually also have to work on problems in their shoulders and elbows, Dr. Weiss says.

During that time they gradually regain their strength and mobility. Patients are in a splint for the first few weeks, and after that they wear the splint only at night and use the hand normally during the day.

The surgery is very effective at reducing pain, Dr. Bridgeman says, but most patients lose range of motion in the joint over time.

There is also a small risk of damage to the implant. Up to 30% of replacement knuckles break, although some studies have found higher rates of fracture.

If that doesn't happen, knuckle implants—like artificial knees—tend to break down after about 10 to 15 years, at which point the finger begins to feel unstable and wobbly, Dr. Weiss says. Five to 10 years after surgery, some patients experience stiffness, joint breakage or dislocation, and recurrent pain.

The number of people potentially needing knuckle replacement surgery could rise in the coming years as more Baby Boomers are afflicted with osteoarthritis—a disease that occurs as we age. But Dr. Hadler says he and other doctors would be wise to help patients improve their joints and work around problems in lieu of having surgery.

"The goal is make it so our patients don't need the surgery in the first place," he says. "I would rather we have them use large pens and get different doorknobs [that are easier to grip] than have surgery."