ObjectiveTo analyze the correlation between bone cement cortical leakage and injury degree of osteoporotic vertebral compression fracture (OVCF) after percutaneous kyphoplasty (PKP), and to provide guidance for reducing clinical complications. Methods A clinical data of 125 patients with OVCF who received PKP between November 2019 and December 2021 and met the selection criteria was selected and analyzed. There were 20 males and 105 females. The median age was 72 years (range, 55-96 years). There were 108 single-segment fractures, 16 two-segment fractures, and 1 three-segment fracture. The disease duration ranged from 1 to 20 days (mean, 7.2 days). The amount of bone cement injected during operation was 2.5-8.0 mL, with an average of 6.04 mL. Based on the preoperative CT images, the standard S/H ratio of the injured vertebra was measured (S: the standard maximum rectangular area of the cross-section of the injured vertebral body, H: the standard minimum height of the sagittal position of the injured vertebral body). Based on postoperative X-ray films and CT images, the occurrence of bone cement leakage after operation and the cortical rupture at the cortical leakage site before operation were recorded. The correlation between the standard S/H ratio of the injured vertebra and the number of cortical leakage was analyzed. Results Vascular leakage occurred in 67 patients at 123 sites of injured vertebrae, and cortical leakage in 97 patients at 299 sites. Preoperative CT image analysis showed that there were 287 sites (95.99%, 287/299) of cortical leakage had cortical rupture before operation. Thirteen patients were excluded because of vertebral compression of adjacent vertebrae. The standard S/H ratio of 112 injured vertebrae was 1.12-3.17 (mean, 1.67), of which 87 cases (268 sites) had cortical leakage. The Spearman correlation analysis showed a positive correlation between the number of cortical leakage of injured vertebra and the standard S/H ratio of injured vertebra (r=0.493, P<0.001). ConclusionThe incidence of cortical leakage of bone cement after PKP in OVCF patients is high, and cortical rupture is the basis of cortical leakage. The more severe the vertebral injury, the greater the probability of cortical leakage.