A Meta-Analysis Study to Define Variations in Murine Long Bone Biomechanical Testing

Abstract

A systematic literature search and meta-analysis were performed to evaluate the variability in biomechanical testing of murine long bones, specifically focused on point-bending tests of mice femora. Due to the lack of standardized protocols for these tests, the assessment quantifies the heterogeneity in reported mechanical properties across existing literature. This study followed preferred reporting items for systematic reviews and meta-analyses (PRISMA) and strengthening the reporting of observational studies in epidemiology (STROBE) guidelines to search publicly available databases for relevant studies. After title and abstract screening, full-text reviews identified 73 articles meeting the inclusion criteria. Data was extracted from these studies, including stiffness, maximum load, modulus, and ultimate stress values for both three-point and four-point bending tests. The data were analyzed through ANOVA and metaregression to assess variability caused by age, sex, and genetic strain. The reviewers also assessed the quality of the included studies. The meta-analysis revealed significant heterogeneity in reported mechanical properties, with I2 values ranging from 72% to 100% in the three point-bend tests of pooled genetic strains. This heterogeneity persisted even after accounting for age, sex, and genetic strain differences. The review concludes that nonstandardized testing setups are the likely major source of the observed variability in reported data more than the population characteristics of the mice, highlighting the need for more consistent testing methodologies in future studies.