Ozone injections reduce pain in knee osteoarthritis: a systematic review and meta-analysis

The only intra-articular injections recommended by international guidelines for the treatment of knee osteoarthritis are injections of corticosteroids and hyaluronic acid; nonetheless, other substances including ozone, dextrose and platelet-rich plasma are also used in clinical. Intra-articular injections of ozone have been reported to have anti-inflammatory mechanisms and clinical benefits similar to intra-articular injections of corticosteroids in patients with knee osteoarthritis; however, this treatment has not been evaluated in a meta-analysis. The objective of this review is to evaluate the effectiveness of intra-articular injections of ozone for reducing pain and improving function in individuals with knee osteoarthritis when compared with intra-articular injections of corticosteroids. An online search was performed using the electronic databases PubMed, EMBASE, Central Cochrane and Web of Science, for controlled clinical trials that compared intra-articular injections of ozone and intra-articular injections of corticosteroid in the treatment of knee osteoarthritis. Seven clinical trials were included in this review, gathering 409 individuals with knee osteoarthritis. In the pooled analysis, ozone injections were found to be more effective in reducing pain in the short and medium terms than corticosteroids injections. Similarly, function improvement in the medium term was observed in favor of ozone injections. Our results suggest that ozone injections represent a good alternative to corticosteroids injections for reducing pain in the short and medium terms in individuals with knee osteoarthritis. Nonetheless, definitive conclusions could not be drawn due to the limited quality of the included studies. Better quality clinical trials are needed to strengthen the evidence and confirm these results.