Risk factor analysis of refracture in the same cemented vertebra after percutaneous kyphoplasty for Kümmell’s disease

OBJECTIVE: The objective of this study was to evaluate the factors that affect refracture in the same cemented vertebra after percutaneous kyphoplasty (PKP) for Kümmell's disease (KD) and establish a risk prediction score. METHODS: A total of 2932 patients who were treated with PKP for KD between January 2019 and December 2021 were retrospectively reviewed. After inclusion and exclusion criteria were applied, 191 patients were included in the study. According to the criteria for refracture, there were 50 patients in the refracture group and 141 patients in the no-refracture group. Twenty-five factors were analyzed. Patient demographics, medical history, imaging data, surgical data, and postoperative management were reviewed. Multivariate logistic regression modeling was used to identify the independent risk factors for refracture. Receiver operating characteristic (ROC) curve analysis was used to assess and establish a risk score system and further predict the risk of refracture. RESULTS: In this study, 50 (26.2%) patients developed a refracture. Through univariate analysis, bone mineral density (BMD) (p < 0.001), compression rate (p = 0.007), classification (i.e., the stages determined by the compression ratios) (p < 0.001), bone cement volume (p < 0.001), volume fraction (p < 0.001), distribution pattern (p = 0.007), non-PMMA endplate contact (p < 0.001), and anti-osteoporosis therapy (p < 0.001) were found to be significant factors for post-cement vertebral refracture after PKP in patients with KD. Three independent risk factors were found to be significant for refracture: small volume fraction, low BMD, and no anti-osteoporosis therapy. One point was assigned for each factor. The incidence rates of refracture in patients with scores of 0, 1, 2, and 3 were 3.7%, 4.4%, 42.0%, and 100%, respectively. The area under the ROC curve for this risk prediction score was 0.888 (p < 0.001), indicating moderate accuracy. CONCLUSIONS: Volume fraction, BMD, and osteoporosis therapy are the main factors influencing the refracture of the same cemented vertebra in KD. On the basis of these factors, the risk prediction score developed in this paper can be used to forecast the incidence of refracture.