Relationship between vertebral height restoration, Cobb angle correction, and refracture after percutaneous vertebroplasty in osteoporotic vertebral compression fractures: a systematic review of primary studies

The relationship between anterior vertebral height restoration rate (AVHRR), Cobb angle correction rate (CACR), and postoperative refracture following percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) for osteoporotic vertebral compression fractures (OVCF) remains controversial. This systematic review of primary studies aims to critically appraise the available evidence and provide cautious, evidence-based clinical considerations. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines and was prospectively registered with PROSPERO (CRD420261440727; registered 15 January 2025). Literature searches were performed in PubMed/MEDLINE, Embase, Cochrane Library, Web of Science, CNKI, and Wanfang Data from inception to 15 August 2026. Only primary studies (randomized controlled trials [RCTs], cohort studies, and case–control studies) were included; systematic reviews and meta-analyses were excluded from the evidence synthesis to prevent duplicate counting of patient cohorts. Non-English and Chinese-language articles were professionally translated with independent back-translation verification. Study quality was assessed using the Newcastle–Ottawa Scale (NOS) for observational studies and the Cochrane Risk of Bias tool (RoB 2) for RCTs. Certainty of evidence was evaluated using the GRADE framework. Because of substantial clinical and methodological heterogeneity, quantitative meta-analysis was deemed inappropriate; a narrative synthesis stratified by refracture subtype was performed instead. Twenty-eight primary studies were included (14 retrospective cohorts, 4 prospective cohorts, 3 RCTs, and 7 case–control studies). GRADE assessments indicated very low to moderate certainty across outcomes; no outcome reached high certainty. Most high-quality primary studies support that over-correction is associated with increased refracture risk, but the association direction and magnitude varied by refracture subtype. For cemented vertebral re-collapse, Wu et al. (2025, n=168) identified CACR as an independent risk factor (odds ratio [OR] 1.070, 95% confidence interval [CI] 1.034–1.109, P < 0.001). Li et al. (2018, n = 180) reported that a higher anterior vertebral height ratio increased re-collapse risk (hazard ratio [HR] 9.29, 95% CI 1.32–65.60, P = 0.012). Yang et al. (2026, n = 180) similarly found AVHR (HR 9.29, 95% CI 1.32–65.60, P = 0.012) and Cobb angle restoration (HR 0.71, 95% CI 0.61–0.83, P < 0.001) as independent predictors. However, the identical HR, CI, and sample size between Li et al. (2018) and Yang et al. (2026) raise concern for overlapping cohorts or transcription error; we flag this uncertainty and urge cautious interpretation. For adjacent vertebral fracture, Gu et al. (2024), n = 528 observed higher refracture rates in the high-restoration group (7.9 vs. 4.4%). Wang et al. (2024), n = 198) reported that each 1-degree increase in CACR conferred approximately 17% higher adjacent-segment refracture risk (OR 1.168, 95% CI 1.028–1.426, P = 0.039). For distant new vertebral compression fracture, Zhang et al. (2025) identified 16.8% AVHRR as a critical inflection point. These thresholds are exploratory and require prospective validation. Yang et al. (2026) developed a four-factor predictive model (cement distribution, bone mineral density [BMD], AVHR, Cobb angle restoration) with an area under the curve (AUC) of 0.89. However, this single-center retrospective model lacks external validation and remains hypothesis-generating. Current primary evidence suggests a likely nonlinear relationship between AVHRR, CACR, and refracture after PVP/PKP, with moderate restoration appearing preferable to overcorrection. Exploratory observational thresholds (AVHRR approximately 10–16.8%; postoperative Cobb angle approximately 10–15 degrees) require prospective validation and should not be regarded as firm operative targets. Bone cement distribution pattern, BMD, and anti-osteoporosis treatment adherence are critical confounding modifiers. Multivariable predictive models, while conceptually promising, remain hypothesis-generating until externally validated. Clinical practice should embrace individualized, patient-centered decision-making that balances radiographic restoration with biomechanical safety, procedural risks, and skeletal protection.