Objective:To identify the risk factors affecting the healing of defective bony nonunion.Methods:The studies reporting the risk factors for healing of defective bony nonunion between January 2000 and March 2022 were retrieved by computer from the VIP, Wanfangdata, CNKI, Web of Science, PubMed, and Medline databases. The Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of the included studies. the RevMan 5.3 software was used to perform a meta-analysis of the general factors, injuries and surgical-related factors affecting the healing of defective bony nonunion.Results:Included in this Meta analysis were 17 studies with 1,236 patients. The NOS score of the included studies was from 5 to 8. The meta-analysis showed the following: age ( MD=-4.27, 95% CI: -8.29 to 2.91, P < 0.01), smoking ( OR=3.56, 95% CI: 2.81 to 6.32, P < 0.01), soft tissue defect ( OR=3.54, 95% CI: 2.21 to 5.69, P < 0.01), combined ipsilateral fibular fracture ( OR=4.18, 95% CI: 1.24 to 14.03, P=0.02), venous thrombosis ( OR=4.27, 95% CI: 1.05 to 17.44, P=0.04), and postoperative infection ( OR=2.96, 95% CI: 1.97 to 4.47, P < 0.01) were significant risk factors for the healing of defective bone nonunion. Minor bone defect ( SMD=-0.67, 95% CI: -1.25 to -0.10, P=0.02), proximal to distal bone transport ( OR=-0.42, 95% CI: 0.22 to 0.77, P < 0.01), short-term external fixation ( MD=-3.92, 95% CI: -7.10 to -0.73, P=0.02), and autologous bone grafting ( OR=0.39, 95% CI: 0.16 to 0.95, P=0.04) were protective factors for the healing of defective bony nonunion. Conclusions:High age (senility), smoking, soft tissue defect, ipsilateral fibular fracture, venous thrombosis, and postoperative infection are risk factors affecting the healing of defective bony nonunion. Minor bone defect, proximal to distal bone transport, short-term external fixation, and autologous bone grafting are protective factors affecting the healing of defective bony nonunion. Surgeons can predict early the prognosis of patients with defective bony nonunion based on the above factors.