Steroid injections don't do a lot to help relieve the pain of arthritis in the knees, a new study has found, suggesting the common treatment may be not be helpful.

The study found that giving patients cortisone injections every three months was no better than giving them a placebo injection for alleviating their knee pain in patients from osteoarthritis.

In fact, the researchers found that the steroid injections actually contributed to a loss in cartilage over two years.

Osteoarthritis is the most common type of arthritis, affecting more than three million Canadians. The condition is marked by the breakdown in joints of cartilage, which is the tough elastic material that protects the ends of bones.

When the underlying bones begin to rub together, it results in pain and stiffness. It can also lead to synovitis, which is an inflammation of the membrane that lines the joints.

There is no cure for the condition, but doctors sometimes inject corticosteroids directly into the knee joint in a bid to quickly reduce some of the inflammation.

Some doctors are reticent to offer the treatment since it's known that repeated injections can actually contribute to the breakdown of cartilage in the knee.

For the study, a team led by Dr. Timothy E. McAlindon, of Tufts Medical Center in Boston randomly assigned 140 patients with knee osteoarthritis and synovitis to injections of either a corticosteroid called triamcinolone, or a simple saline solution, every 12 weeks for two years.

“I’d hoped that we might see some benefit from the triamcinolone because it supresses inflammation and we know there is inflammation in the knee joints,” McAlindon said.

The researchers found that those receiving the injections of triamcinolone saw significantly greater cartilage volume loss than the saline group saw.

And though both groups experienced some relief from pain, there wasn't a significant difference between the two groups. Physical function remained about the same in both groups as well.

"The results of this study do not support the use of long-term, repeated corticosteroid injections for the management of pain or structural progression in osteoarthritis, and in fact indicate that there may be more cartilage loss in people who receive steroids," McAlindon said.

The study appears in the Journal of the American Medical Association.

Dr. Bheeshma Ravi, an orthopaedic surgeon at Sunnybrook Health Sciences Centre in Toronto, says the study confirms what a lot of surgeons have known for some time.

This study will really help doctors and patients understand these injections -- especially steroid injections -- don’t really have much of an impact on patient pain and should not really be part of the care,” he told CTV News.

Ravi believes that many steroid injections are "patient-driven," meaning it's patients who are requesting them because they have exhausted other pain management options but are leery of having joint replacement surgery.

"A lot of doctors use these injections in lieu of counselling patients that they may benefit from surgery," Ravi said

But the injections rarely work to relieve pain and only serve to delay joint replacement surgery, which has been shown to relieve pain and increase mobility.

"Sometimes people delay surgery for too long -- and sometimes they do that by using these injections and various other injections offered -- they may get to a stage where their function is so low, that the surgery can't really make much of a difference (to their ability to function)."

With a report by CTV News medical specialist Avis Favaro and producer Elizabeth St. Philip