According to the preset inclusion and exclusion criteria, randomized controlled trials and cohort studies on hyperbaric oxygen in the treatment of ORNJ were screened, and foreign language databases such as PubMed, EMBASE, and Cochrane library were searched via a computer; Chinese databases such as CNKI, VIP, Wanfang data, and CBM were searched from the established database to September 2020. Relevant books were searched manually to collect all literatures on the efficacy of hyperbaric oxygen and its related therapies in ORNJ treatment. Two researchers were independent and mutually blind, the papers were selected, data were collected, and the bias risk was evaluated. If any difference was detected, it would be decided by discussion or arbitrated by a third party. The data related to the efficacy of hyperbaric oxygen and its related therapy in the treatment of the ORNJ were extracted, and the Revman5.4 software was used for Meta-analysis. In case of large heterogeneity, sensitivity analysis was performed. A funnel chart was used to evaluate possible publication bias qualitatively.

Four randomized controlled trials and seven cohort studies were included in Meta-analyses. In ORNJ treatment, no significant differences between the group subjected to hyperbaric oxygen and both surgery and antibiotics and the group that underwent both surgery and antibiotics (RR=1.16, 95%CI: 0.86~1.58, P>0.05); between the group with hyperbaric oxygen and the group with antibiotics (RR=0.83, 95%CI: 0.63~1.09, P>0.05); between the group with hyperbaric oxygen and the group with antifibrotic drugs (RR=0.07, 95%CI: 0.00~155.86, P>0.05); between the group with single or combined use of HBO and the group with other intervention methods (RR=0.89, 95%CI: 0.67~1.19, P>0.05).

Hyperbaric oxygen therapy cannot replace surgery and antibiotic therapy. Hyperbaric oxygen therapy is not superior to antibiotics and antifibrotic drugs, but the benefits of antifibrotic drugs should be further explored.