VBQ and Hounsfield Units Predict Subsequent Fractures After Vertebral Augmentation

This systematic review and meta-analysis evaluated the diagnostic accuracy of vertebral bone quality (VBQ) scores and Hounsfield Units (HU) values for identifying subsequent fractures (SF) following vertebral augmentation (VA) in patients with osteoporosis. The analysis included 7364 patients from multiple studies, comparing those who developed SF (SF group) with those who did not (non-SF group). The primary outcome was the diagnostic performance of VBQ and HU for predicting SF.

Results showed that VBQ scores were significantly higher in the SF group compared with the non-SF group, with a mean difference of 0.58 (95% CI: 0.41-0.74, P < 0.001). Conversely, HU values were significantly lower in the SF group, with a mean difference of -24.69 (95% CI: -28.46 to -20.92, P < 0.001). These findings indicate that both markers are associated with fracture risk, but in opposite directions: higher VBQ (indicating poorer bone quality) and lower HU (indicating lower bone density) predict subsequent fractures.

Diagnostic accuracy was assessed using hierarchical summary receiver operating characteristic (HSROC) curves. The area under the HSROC curve for VBQ was 0.85, compared with 0.82 for HU. Sensitivity for VBQ was 0.85, and specificity was 0.66. For HU, sensitivity was 0.79, and specificity was 0.70. These results suggest that VBQ has slightly better overall diagnostic performance, particularly in sensitivity, while HU offers higher specificity.

Heterogeneity was substantial, with I² values of 85% for VBQ and 87% for HU, indicating considerable variability across studies. The source of heterogeneity for VBQ was identified as the site of subsequent fracture (SF site), but no significant modifiers were found for HU. This heterogeneity limits the precision of pooled estimates and suggests that results should be interpreted cautiously.

Safety and tolerability data were not reported in this meta-analysis, as the focus was on diagnostic accuracy rather than intervention outcomes. No adverse events, serious adverse events, or discontinuations were described. Funding sources and conflicts of interest were also not reported.

Compared with prior studies, this meta-analysis consolidates evidence on two imaging biomarkers for fracture prediction after VA. Previous research has established low HU as a risk factor for osteoporosis-related fractures, but the role of VBQ—a measure of bone marrow fat content—is less well-known. This analysis suggests VBQ may be a complementary or superior tool, though the high heterogeneity warrants caution.

Key methodological limitations include the substantial heterogeneity across studies, which may reflect differences in patient populations, imaging protocols, or definitions of subsequent fracture. The analysis did not adjust for potential confounders such as age, sex, or comorbidities. Additionally, the retrospective nature of included studies may introduce selection bias. The absence of safety data and funding disclosures further limits the assessment of study quality.

Clinically, these findings suggest that both VBQ and HU can be used to identify patients at higher risk for subsequent fractures after vertebral augmentation. VBQ appears to have better sensitivity, making it useful for screening, while HU offers higher specificity. However, due to heterogeneity, these markers should be integrated with other clinical risk factors rather than used in isolation.

Several questions remain unanswered. The optimal threshold values for VBQ and HU in this context have not been established. Prospective studies are needed to validate these findings and to determine whether interventions based on these markers can reduce fracture risk. The impact of different VA techniques and postoperative management on the predictive value of these markers also requires investigation.