Can viscosupplements alleviate osteoarthritis?
Osteoarthritis is often referred to as “wear and tear” arthritis and affects a large part of the population. It happens as people grow older, but can also be caused by obesity or joint injuries.
No cure for osteoarthritis
Weight-bearing joints like the hips, feet, spine and knees are the areas that are most affected by osteoarthritis.
According to the American National Institutes of Health (NIH) osteoarthritis mostly affects cartilage. Cartilage is the slippery tissue that covers the ends of bones in a joint, allowing bones to glide over each other. In osteoarthritis, the top layer of cartilage wears away, which causes bones under the cartilage to rub together.
Read: Knee cartilage regrown
This rubbing motion can cause symptoms like pain, swelling, tenderness, stiffness, loss of flexibility, “grating” and bone spurs.
Apart from joint replacement surgery there is no cure for osteoarthritis, but a lot can be done to alleviate symptoms and prevent the situation from becoming worse. Some ways to relieve the pain of osteoarthritis and improve mobility are:
- Weight loss
- Anti-inflammatory medication
- Pain relievers
- Steroid injections
- Corticosteroid injections
- Hyaluronic acid injections/viscosupplementation
- Alternative medicine
- Physical devices
- Physical therapy
Hyaluronic acid injections
When nothing else has worked, many doctors are willing to give hyaluronic acid injections a try before turning to surgery (knee replacement), especially if the patient can’t take painkillers like ibuprofen and paracetamol. The side effects are mild, recovery time is short, and there is a lot of anecdotal evidence for the effectiveness of viscosupplementation.
Read: Total knee replacement
Hyaluronic acid is a natural substance in the synovial fluid surrounding joints where it lubricates bones, enabling them to move smoothly over each other. Osteoarthritis sufferers have less hyaluronic acid in their joints than other people and the idea is that injecting hyaluronic acid into the affected joint will provide relief from arthritic symptoms.
According to SANOFI, to prepare your knee for injection your doctor may:
- Clean your knee with alcohol and/or iodine
- Apply a local anaesthetic to your knee
- Insert a needle into your joint
- Withdraw any excess fluid from your joint
- Inject the viscosupplement into your knee joint (intra-articular injection)
The procedure only takes a few minutes and you can go home directly afterwards. At home the patient is advised to rest and to avoid putting strain on the knee. Any pain may be alleviated with an ice pack. Side effects are usually mild and temporary.
Sanofi says that for people with osteoarthritis of the knee relief has been shown to last up to a year with three viscosupplement injections. Success varies from person to person and repeat treatment is safe and effective.
Hyaluronic acid is often made from rooster combs, and patients who are allergic to chicken products should avoid viscosupplements from avian sources.
'Minimal or nonexistent benefit'
Viscosupplementation is widely used for symptomatic knee osteoarthritis to improve biomechanical function, and the FDA approved it in 1997.
Although popular, the therapy is controversial, and Anne W.S. Rutjes, PhD, with the Institute of Social and Preventive Medicine, at the University of Bern, in Bern, Switzerland, and colleagues reported their findings regarding the practice online June 12, 2012 in the Annals of Internal Medicine.
The conclusion of the authors’ meta-analysis was: “The benefit of viscosupplementation on pain and function in patients with symptomatic osteoarthritis of the knee is minimal or nonexistent." They also found that the procedure increased the risk for “serious adverse events”.
The American Academy of Orthopaedic Surgeons (AAOS) also recently stated in their guidelines for the treatment of osteoarthritis of the knee that they cannot recommend using hyaluronic acid (HA) for patients with symptomatic osteoarthritis of the knee. (This is bad news for companies like SANOFI that sell hyaluronic acid [HA].)
Health24 asked Cape Town rheumatologist Dr David Gottlieb about the use of viscosupplementation for osteoarthritis. He replied via email that he has no strong belief in the therapy and doesn’t “think it works any better than a cheap cortisone injection” and doesn’t use it anymore.
For some it works
There are however influential organisations that strongly advocate the use of viscosupplementation.
An article by the American Arthritis Foundation gives what is probably the best assessment of the situation, stating that the weight of evidence suggests that a (hyaluronic acid) shot in the knee may bring some osteoarthritis patients relief. And although studies of viscosupplementation have yielded some disappointing results, many doctors who treat osteoarthritis say that, in their clinical experience, hyaluronic acid can produce significant relief for some patients.
Arthritis Research UK also sends out a generally positive message: “Hyaluronan injections are most useful in osteoarthritis when the smooth, highly polished surfaces of the joint have become roughened but there’s no significant inflammation.”
Cost of viscosupplementation
According to The Journal of Family Practice the cost of one hyaluronic acid (30 mg/mL) injection is approximately $230 (R3 500). If you receive a course of three to five weekly knee injections, your total cost per treatment could be more than $1 000 (R15 500) per knee. This is a lot of money and the benefit of viscosupplementation must be carefully compared with other therapies.