Study questions efficacy and safety of knee injections

If you're one of the estimated 27 million Americans with osteoarthritis, you're probably all too familiar with the feeling of aching, swollen, or stiff knees.

Nonsteroidal anti-inflammatory drugs such as ibuprofen may relieve those painful symptoms in most patients. But for others, doctors may prescribe a more invasive treatment that involves injecting hyaluronic acid in to the knee, called viscosupplementation. 

Now, a new report questions the efficacy of this treatment for osteoarthritis in the knee. 

Hyaluronic acid is a lubricating fluid that is naturally found in the knee, but degenerates over time in people with osteoarthritis. The effect of the injection used in viscosupplementation is to stimulate cells in the knee to increase production of hyaluronic acid.

In a meta-analysis of 177 reports that included data on more than 12,000 patients with osteoarthritis in the knee, researchers at the Institute of Social and Preventive Medicine at the University of Bern in Switzerland concluded that the treatment "has minimal benefits and potential for harm."

They write that "because of increased risks for serious adverse events and local adverse events, the administration of these preparations should be discouraged."

Dr. John Richmond disagrees. He is the Chairman of the Orthopedics Department at New England Baptist Hospital and the previous Chair of the American Academy of Orthopaedic Surgeons (AAOS) working group on treatment of osteoarthritis in knees.

"We have an epidemic of osteoarthritis of the knee and we have limited treatment options," says Dr. Richmond, who was not affiliated with the analysis but who reviewed the same data it was based on. "This needs to remain one of those limited treatment options and should be used appropriately by the physician giving it."

The most common side effects patients undergoing viscosupplementation may endure are flare-ups -  where the knee becomes hot and swollen within 24 hours after the injection - and effusions, where excessive joint fluid collects inside the knee.  The researchers in Switzerland reviewed the existing studies and concluded that viscosupplementation was associated with an increase in these and other adverse events.

Dr. Richmond, who has independently reviewed the same research when the AAOS was drafting their recommendations to treat osteoarthritis of the knee, argues that despite infrequent instances of those side-effects, viscosupplementation remains a solid treatment choice for some patients.

"This is most effective in relatively younger patients, 40 to 50 to 60 year olds, and...in people with mild to moderate forms of the disease," says Richmond. "This is not a first line treatment, but it's a reasonable treatment in those people who have been appropriately screened."

The authors of the study discourage patients from getting this treatment. However, Richmond says patients considering viscosupplementation should discuss this as a treatment option with their doctor.