Biomechanics of Traumatic Brain Injury: A Systematic Review of Mechanisms, Computational Models, and Clinical Translation

Traumatic brain injury (TBI) is a major global health challenge. Biomechanical approaches linking external forces to tissue-level injury have advanced substantially with computational modelling. This systematic review synthesises recent evidence (2020–2025) on TBI biomechanics, focusing on computational models, injury thresholds, and clinical translation across sports, automotive, blast, and fall contexts.

A systematic search of PubMed/MEDLINE, Google Scholar, SciSpace, and ArXiv was conducted between 1 and 15 December 2025 following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Database-specific search strings, filters, and exact retrieval dates are reported in full in Supplementary Material 1, and the rationale for the database selection — including the non-inclusion of Embase, Scopus, Web of Science, and the Cochrane Library — is detailed in the Methods section. From 928 records, 267 unique papers were screened by two independent reviewers (κ = 0.82). Following sequential screening (267 → 50 → 30 eligible → 19 finally synthesised), nineteen studies underwent narrative synthesis with a customised quality assessment framework whose full scoring rubric is provided in Supplementary Material 3.

Included studies comprised computational modelling (n = 13), experimental (n = 3), reviews (n = 2), and combined designs (n = 1). Angular acceleration and velocity consistently predicted brain tissue deformation more strongly than linear acceleration. Maximum principal strain (MPS) emerged as a tissue-level predictor (concussion: MPS ≈ 0.15–1.0; diffuse axonal injury [DAI]: MPS ≈ 1.6); thresholds are model-dependent and should be interpreted with caution, as different validated finite element models produce substantially different strain values under identical loading conditions. Finite element models demonstrated variable validation performance (CORrelation and Analysis [CORA] scores: 0.50–0.85), with strain predictions differing meaningfully between models under identical loading conditions; CORA scores reflect kinematic fidelity rather than direct tissue-strain accuracy. Protective equipment reduced intracranial pressure by 19–52%. Females showed increased axonal susceptibility.

Computational biomechanics has proposed model-derived injury thresholds with practical utility for prevention and equipment design; however, these thresholds remain model-dependent and require cautious interpretation pending robust cross-model experimental validation. Findings from computational modelling describe model-predicted tissue deformation and biomechanical injury risk; direct inferences to clinically diagnosed TBI must be drawn cautiously and only where supported by experimental or clinical validation. Critical gaps remain in sex-specific modelling, age-specific thresholds, and cumulative subconcussive effects.