A multimodal imaging approach to predict carpal tunnel syndrome after distal radius fractures.

OBJECTIVE: Distal radius fractures are commonly associated with the development of carpal tunnel syndrome (CTS), yet current evidence primarily focuses on radiographic alignment parameters. The role of carpal tunnel morphology, particularly total carpal tunnel cross-sectional area (CSA) measured on computed tomography (CT), remains insufficiently investigated. This study aimed to evaluate the relationship between CSA, volar tilt, and the development of CTS in conservatively managed distal radius fractures, and to assess the predictive performance of these parameters when used in combination.

METHODS: This retrospective case-control study included 150 patients, comprising 50 patients who developed CTS and 100 controls without CTS. CSA was measured on CT scans obtained at initial presentation, while volar tilt was assessed using standard radiographs. Additional variables, including the presence of ulna fracture and fracture type, were analyzed. Group comparisons were performed using nonparametric tests. Multivariable logistic regression analysis was conducted to identify independent predictors of CTS. Diagnostic performance was evaluated using receiver operating characteristic (ROC) curve analysis.

RESULTS: Patients who developed CTS had significantly lower CSA and higher volar tilt values (both p < 0.001). The presence of an ulna fracture was inversely associated with CTS (p = 0.004). Multivariable analysis identified CSA (OR = 0.748, 95% CI: 0.643-0.871, p < 0.001), volar tilt (OR = 1.132, 95% CI: 1.051-1.219, p = 0.001), and ulna fracture (OR = 0.249, 95% CI: 0.076-0.817, p = 0.022) as independent predictors of CTS. ROC analysis showed moderate discriminative ability for CSA and volar tilt individually (AUC = 0.685 and 0.708, respectively), which improved when combined (AUC = 0.772). The highest predictive performance was achieved with the combined model including CSA, volar tilt, and ulna fracture (AUC = 0.802).

CONCLUSION: In conservatively managed distal radius fractures, carpal tunnel cross-sectional area (CSA) and volar tilt are independently associated with the development of CTS. While CSA alone demonstrates limited discriminative ability, its combination with radiographic parameters appears to improve predictive performance. These findings suggest that incorporating CT-based morphological measurements alongside conventional radiographic assessment may provide additional value in early risk stratification for CTS.

LEVEL OF EVIDENCE: Level III, retrospective casecontrol study.