A quantitative analysis of bone defects in displaced proximal humeral fractures using virtual reduction technique

Abstract

Background and Objective

Medial column disruption in proximal humeral fractures (PHFs) is associated with poor outcomes following reduction and internal fixation. Current assessments of unstable medial columns rely on qualitative descriptors such as disrupted hinges and insufficient osseous contact, often overlooking the quantification of bone defects. This study aims to quantitatively analyze bone defect characteristics in varus PHFs using advanced computer image processing techniques.

Methods

A retrospective cohort study was conducted on 202 patients diagnosed with varus proximal humeral fractures who received treatment at two tertiary hospitals between January 2017 and December 2022. Three-dimensional (3D) fracture models were reconstructed using Mimics software based on preoperative computed tomography (CT) scans, followed by virtual reduction procedures performed in 3-matic software. Comprehensive demographic and morphological data were collected, including patient age, gender distribution, fracture classification, and quantitative parameters of bone defects the volume of bone defect (VBD), extent of bone defect area (EBDA), main defect region (MDR), and maximal defect height (MDH).

Results

Quantile regression demonstrated that age exhibited strong positive associations with VBD across all quantiles (P < 0.001). EBDA and MDH showed consistently significant positive associations with VBD at every quantile level (all P < 0.001). For Sex, males showed no statistically significant differences compared to females (all P > 0.05). Among fracture classifications, 2-part fracture and 3-part fracture had comparable VBD values to 4-part fracture in most quantiles (all P > 0.05), except for 2-part fracture at Q90 (P = 0.017).

Conclusion

This study demonstrates that all varus PHFs with significant displacement are associated with bone defects. Age, EBDA, and MDH are positively correlated with VBD, highlighting the importance of considering these factors in surgical planning.