Second metacarpal cortical percentage and psoas muscle index in predicting loss of reduction after non-operative treatment of distal radius fractures in adult women.

Abstract

Objectives: This study aims to investigate whether second metacarpal cortical percentage (2MCP) and psoas muscle index (PMI) were associated with loss of reduction after closed reduction and cast immobilization.

Patients and methods: A total of 91 adult female patients with distal radius fractures (DRFs) treated with closed reduction and cast immobilization between January 2014 and June 2025 were retrospectively analyzed. Patients with standardized serial radiographs and lumbar computed tomography (CT) performed within ± 3 months of injury were included. Clinical characteristics, AO/OTA fracture type, Lafontaine instability criteria, lumbar CT densitometry T-scores, 2MCP, and PMI were evaluated. Loss of reduction was defined radiographically during follow-up. Multivariate logistic regression was performed using predefined cut-off values, and receiver operating characteristic (ROC) curve analysis was used to explore cut-off values for 2MCP and PMI.

Results: The mean age was 63.0 ± 8.2 (range, 44 to 84) years. Loss of reduction occurred in 23 patients (25.3%). In group comparisons, AO/OTA Type C fracture pattern, Lafontaine instability, CT densitometry-defined osteoporosis, 2MCP-defined osteoporosis, and low PMI were more frequent among patients with loss of reduction. In the multivariate analysis, 2MCP-defined osteoporosis was independently associated with loss of reduction (adjusted OR = 7.22; 95% CI: 1.16-45.06; p = 0.034). Low PMI was also independently associated with loss of reduction (adjusted OR = 25.52; 95% CI: 5.33-122.14; p < 0.001). The ROC curve analysis identified cut-off values of 48% for 2MCP and 3.65 for PMI.

Conclusion: Our study results showed that 2MCP-defined osteoporosis and low PMI were independently associated with loss of reduction after non-operative treatment of DRFs in female patients. These imaging-based parameters may support exploratory risk stratification.