Two recent studies presented at the American College of Rheumatology’s annual meeting in San Francisco in November looked at old and new treatment for knee osteoarthritis.

One study found that a popular therapy, steroid drug injections, do nothing to slow progression of osteoarthritis in the knee. This type of treatment is common, but has never been specifically tested, and there are concerns about its safety, according to a team led by Dr. Tim McAlindon, chief of rheumatology at Tufts Medical Center in Boston.

The study tracked outcomes for 140 people, mainly overweight white women, with knee osteoarthritis who averaged 58 years of age. The patients received either injections of the steroid triamcinolone hexacetonide, or placebo injections of saline, every three months for two years.

Steroid injection into an arthritic joint, usually combined with aspiration of inflammatory  fluid, is a time and tested treatment, often relieving pain and increasing mobility dramatically in the short term. Whilst they reduce inflammation they have never been designed to alter the longer term progression of osteoarthritis. They offer welcome relief and the all important chance to mobilise the joint, but many specialists believe their use should be limited to a lifetime total maximum as well as a minimum interval between each one.

This study recruited mostly obese subjects. Without effective weight loss it is not surprising the benefits were transitory.

On the horizon however, a second, small study found that injections of ozone gas into the joint reduced pain and improved movement for people with knee osteoarthritis.

The Brazilian trial included 63 patients who received injections of ozone gas into the knee and a control group of 35 who received injections of air. Previous research has suggested that ozone, a naturally occurring gas, may help reduce inflammation.

The patients who received the ozone gas showed significant improvements in pain, physical function, overall health and quality of life, compared to those in the control group, the researchers said. However, there were no major differences between the two groups in the amount of time it took them to stand up, walk, return and sit.

Ozone injections into damaged knee joints is an interesting development. Oxygen is an effective aid to healing in many conditions, but would I imagine be re-absorbed from a joint space fairly quickly. Perhaps ozone is retained within the joint for longer where it might also act as a cushion against further cartilaginous trauma.

This early study is small and inconclusive, but serves to remind us how important it is to constantly explore potential new treatments. It also demonstrates that when many treatments are designed for short term benefits, perhaps whilst addressing lifestyle corrections, few will ever be a substitute for long term disease modifying therapies.