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Published originally at OnHealth.com, March 29, 2000.
Can new treatments oil creaky knees?
By Sally James
It is the dawning of the Age of Arthritis, if you are old enough to remember the sweet anthem of the 1960s about the Age of Aquarius.
Your knees are stiff, and maybe they hurt after you play basketball or twist through an hour of aerobic dance. Nobody can diagnose you here but let's just say that 20 million other Americans have osteoarthritis, according to the Arthritis Foundation. That number will grow as the Baby Boomers age.
There's no cure for osteoarthritis, or OA, but some new therapies may make painful knees feel better. One of these is called viscosupplementation.
OA is a disease of the articular cartilage, the tough material that covers the ends of the bones. When this protective covering breaks down or thins out entirely, it causes pain, stiffness and eventually can be crippling when bone scrapes naked against bone. Patients get relief from pain medications, and sometimes from steroid injections to the knees, but both of those treatments carry a risk of side effects. Everyone is looking for alternatives.
Two new compounds have been approved and are in use now: Hyalgan and Synvisc. In both cases, they are fluids injected with a needle directly into the knee joint. The two are chemically different, but both are substitutes for a naturally occurring substance in the human body, hyaluronic acid or HA. Patients receive either a series of three or a series of five injections. The benefits usually show up after about 8 weeks and last six months or longer. While the compounds differ, their basic strategy is to help the fluid inside the knee do a better job of lubricating and absorbing the shock of movement.
Bernard Stulberg, M.D., is an orthopedist and the chair of a national committee that reviewed this area of therapy for the American Academy of Orthopaedic Surgeons. He and his partner at the Cleveland Center for Joint Replacement have used it about 150 times.
"There is very little downside," Stulberg explained in an interview. "The material is quite safe and there have been few reported side effects." He believes it offers a valuable new choice to patients with few other alternatives if pain medication and steroid injections don't work. The Food and Drug Administration approved the two compounds in 1997 as injectable medical devices, not as drugs.
Both orthopedists and rheumatologists can offer the therapy, but not every doctor does. The compounds are expensive, costing between $500 and $640 for a series of injections. Medicare does reimburse for the treatment, but some insurers do not.
Hyalgan and Synvisc are both aiming to improve the effectiveness of the synovial fluid. This marvel of biochemical engineering responds to changing conditions in the joint. Sometimes it behaves like a lubricant to help parts slide against each other. Under a sudden load, such as landing from a jump, it changes to more of a solid shock absorber to cushion the impact.
Just as important as the fluid's slippery and shock-absorbing qualities is its ability to help injured cartilage rebuild. Here is where the science shrinks down to the size of molecules and gets extremely murky. Researchers know that HA is an important player in the chemistry, but not precisely why. Put more of this in the joint, the theory goes, and the joint should work better.
Early research shows that both Hyalgan and Synvisc can be effective about 60 percent of the time at temporarily relieving the pain of patients with OA and increasing their ability to move. More studies are needed to clarify why. But patients are not waiting for studies.
"I put my cane down," wrote one 39-year-old woman, about her benefit after a series of injections. She is just one voice of many at on-line chat room for people in line for artificial knees. A San Francisco nurse wrote that she could walk without a limp after her first series.
"It was high relief. Like taking a deep breath and finding the discomfort gone," she described. However, when she had a second series, she felt no relief. Others at the chat room told stories of failure, or of side effects like swelling in their knee. What is crucial for patients to understand is that viscosupplementation does not stop the disease process from continuing. If a patient has end-stage osteoarthritis, they are probably facing joint-replacement surgery sooner or later. The key is whether the new therapy can delay that surgery.
Critics say the early clinical studies are not exhaustive enough and not definitive enough to prove the effectiveness of this therapy. Many doctors say moderate exercise and losing weight are lifestyle changes that cost nothing and can make a dramatic difference for many OA patients.
Ironically, the doctors most likely to prescribe supplementation are specialists who see patients with advanced OA and the therapy might be more effective on patients with milder disease.
Rheumatologist Steven Overman, who is an assistant clinical professor at the University of Washington in Seattle, sees enough promise in this therapy that he had it done to his own arthritic knees. Even if the relief is temporary, he argues, it may allow patients who would be otherwise disabled by pain to continue moving and exercising. In his case, he quit running for exercise and switched to swimming.
Tantalizing, but unproven, is the theory that increasing the amount of HA in the joint fluid could help actually delay the progress of OA and stimulate the body to produce HA on its own. More studies, with larger groups of patients, will be needed to test this out.
Like the Tin Man, whom Dorothy frees from rust with her oil can, arthritis patients hope and wait for the day that someone can design a perfect "oil" for joints that have lost their easy movement. That day is still far off, but this therapy is one step down a long road toward understanding.