{"title":"Comprehensive validation of a custom three-point bending system for standardized diabetic fracture models in rats.","authors":"Qidong Guo, Weijie Wang, Zheng Guo","doi":"10.1186/s13018-025-05754-8","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Diabetes mellitus (DM) significantly impairs fracture healing, necessitating reliable animal models to study diabetic fracture repair mechanisms and therapeutic interventions. This study aimed to develop and comprehensively validate a standardized three-point bending system for inducing precise, reproducible mid-shaft transverse femoral fractures in rats, addressing existing methodological gaps of insufficient reproducibility and detailed calibration in previous models.</p><p><strong>Methods: </strong>A custom-designed three-point bending fracture induction system was developed using AutoCAD software based on the original principle introduced by Einhorn et al. (1984). After manufacturing and calibration, the system was validated first using 22 cadaveric rat femurs and subsequently applied to live rats (n = 44), including diabetic (streptozotocin-induced, n = 22) and non-diabetic animals (n = 22). Fracture induction reproducibility was assessed through radiographic, histologic and mechanic analysis. Additionally, statistical analysis was conducted using GraphPad Prism 9 software. Coefficients of variation (CV) for fracture-healing parameters (callus diameter, calcification ratio, maximum bending force at re-fracture) were calculated and compared statistically with similar parameters from previously published rat femoral fracture studies.</p><p><strong>Results: </strong>Cadaveric validation confirmed that the optimal blade travel distance, set as half the femoral diameter, consistently produced standardized transverse fractures without comminution. A significant correlation between body weight and femoral diameter (Femoral diameter = 1.0276 ln [Body weight] - 1.349) allowed accurate preoperative determination of optimal blade travel distance. Live animal testing demonstrated consistent fracture patterns, stable intramedullary pin fixation, and no complications during surgical procedures. Statistical analysis revealed significantly lower coefficients of variation for healing parameters in this study compared to previously published models (p < 0.05). Histological analysis indicated the fracture type was transverse. Callus was found around fracture site.</p><p><strong>Conclusion: </strong>Our validated three-point bending system significantly enhances reproducibility, consistency, and methodological rigor in animal fracture research. This standardized model provides an ideal foundation for future preclinical studies investigating diabetic fracture healing mechanisms and potential therapeutic interventions.</p>","PeriodicalId":16629,"journal":{"name":"Journal of Orthopaedic Surgery and Research","volume":"20 1","pages":"328"},"PeriodicalIF":2.8000,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11959989/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Orthopaedic Surgery and Research","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1186/s13018-025-05754-8","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ORTHOPEDICS","Score":null,"Total":0}
引用次数: 0
Abstract
Background: Diabetes mellitus (DM) significantly impairs fracture healing, necessitating reliable animal models to study diabetic fracture repair mechanisms and therapeutic interventions. This study aimed to develop and comprehensively validate a standardized three-point bending system for inducing precise, reproducible mid-shaft transverse femoral fractures in rats, addressing existing methodological gaps of insufficient reproducibility and detailed calibration in previous models.
Methods: A custom-designed three-point bending fracture induction system was developed using AutoCAD software based on the original principle introduced by Einhorn et al. (1984). After manufacturing and calibration, the system was validated first using 22 cadaveric rat femurs and subsequently applied to live rats (n = 44), including diabetic (streptozotocin-induced, n = 22) and non-diabetic animals (n = 22). Fracture induction reproducibility was assessed through radiographic, histologic and mechanic analysis. Additionally, statistical analysis was conducted using GraphPad Prism 9 software. Coefficients of variation (CV) for fracture-healing parameters (callus diameter, calcification ratio, maximum bending force at re-fracture) were calculated and compared statistically with similar parameters from previously published rat femoral fracture studies.
Results: Cadaveric validation confirmed that the optimal blade travel distance, set as half the femoral diameter, consistently produced standardized transverse fractures without comminution. A significant correlation between body weight and femoral diameter (Femoral diameter = 1.0276 ln [Body weight] - 1.349) allowed accurate preoperative determination of optimal blade travel distance. Live animal testing demonstrated consistent fracture patterns, stable intramedullary pin fixation, and no complications during surgical procedures. Statistical analysis revealed significantly lower coefficients of variation for healing parameters in this study compared to previously published models (p < 0.05). Histological analysis indicated the fracture type was transverse. Callus was found around fracture site.
Conclusion: Our validated three-point bending system significantly enhances reproducibility, consistency, and methodological rigor in animal fracture research. This standardized model provides an ideal foundation for future preclinical studies investigating diabetic fracture healing mechanisms and potential therapeutic interventions.
期刊介绍：
Journal of Orthopaedic Surgery and Research is an open access journal that encompasses all aspects of clinical and basic research studies related to musculoskeletal issues.
Orthopaedic research is conducted at clinical and basic science levels. With the advancement of new technologies and the increasing expectation and demand from doctors and patients, we are witnessing an enormous growth in clinical orthopaedic research, particularly in the fields of traumatology, spinal surgery, joint replacement, sports medicine, musculoskeletal tumour management, hand microsurgery, foot and ankle surgery, paediatric orthopaedic, and orthopaedic rehabilitation. The involvement of basic science ranges from molecular, cellular, structural and functional perspectives to tissue engineering, gait analysis, automation and robotic surgery. Implant and biomaterial designs are new disciplines that complement clinical applications.
JOSR encourages the publication of multidisciplinary research with collaboration amongst clinicians and scientists from different disciplines, which will be the trend in the coming decades.
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