Ozone-therapy for osteoarthritis? No, thanks!

“Unless positive evidence emerges, the risk/benefit balance of ozone therapy for any condition fails to be positive.”  This is the conclusion I recently drew after assessing the evidence for or against this therapy. Now a new review has just been published. Does it change my verdict?

This review evaluated the available literature on the application of oxygen-ozone therapy (OOT) in the treatment of knee osteoarthritis (KOA) to understand its therapeutic potential and to compare it with other conservative treatment options.

Eleven studies involving 858 patients met the inclusion criteria. Patients in the control groups received different treatments:

• placebo in 1 trial;
• hyaluronic acid in 2 studies;
• hyaluronic acid and PRP in 1 trial;
• corticosteroids in 4;
• hypertonic dextrose, radiofrequency, or celecoxib + glucosamine in the remaining 3 trials.

The quality of these studies was poor; none of the studies included reached “good quality” standard, 2 were ranked as “fair,” and the rest were considered “poor.” No major complications or serious adverse events were reported following intra-articular OOT, which provided encouraging pain relief at short term. On the basis of the available data, no clear indication emerged from the comparison of OOT with other established treatments for KOA.

The authors concluded that the analysis of the available RCTs on OOT for KOA revealed poor methodologic quality, with most studies flawed by relevant bias, thus severely limiting the possibility of drawing conclusions on the efficacy of OOT compared with other treatments. On the basis of the data available, OOT has, however, proven to be a safe approach with encouraging effects in pain control and functional recovery in the short-middle term.

The use of ozone for treatment of KOA is highly controversial. The mechanism of action of ozone therapy for the treatment of KOA is unclear. Some studies have suggested that ozone injections results in pain relief, reduction of oedema, and improved mobility. The above review might be valuable in summarising the evidence, however, I fing its conclusion odd:

• The authors write that they cannot arrive at a verdict about efficacy because of the poor quality of the primary studies. I think the conclusion is very clear and should have been expressed bluntly. THE AVAILABLE DATA FAIL TO SHOW EFFICACY; THE THERAPY IS THUS UNPROVEN AND SHOULD THEREFORE NOT BE USED. Simple!
• I also disagree that OOT was proven to be safe. No treatment can be proven to be safe on the basis of just a few studies. This would require a much, much greater sample size.

This leaves us with the following situation:

1. OOT is not plausible.
2. OOT is unproven.
3. The risks of OOT are unknown.

To me this means that we should stop using it (and I don’t need to change my above-quotes verdict).