Dynamic Response Properties of Lower Extremity Subjected to Side Impact Loading

KANETA, Yutaku; OHKAWA, Hisashi; SUZUKI, Yushi; HARA, Toshiaki · 2008 · DOAJ

DOI: 10.1299/jbse.3.461

archive: archived pipeline: cataloged verified

Get this paper ↗ (DOI — opens at the source; we link to it, we don't host it)

Summary

This study addresses the biomechanical mechanisms of lower extremity injuries in pedestrian-vehicle collisions, motivated by the global increase in elderly populations and the corresponding rise in traffic accidents. While head injuries are often fatal, leg injuries are the most common nonfatal outcome, significantly impairing mobility and quality of life. The authors aim to quantitatively evaluate the risk of femoral fracture using biological specimens, filling a gap in experimental research that has largely relied on dummy or mathematical models since earlier cadaver studies. To simulate side-impact loading, the researchers constructed an experimental setup using a torsion spring and slider-crank mechanism to launch a 3 kg impactor at velocities between 6 and 20 km/h. Fresh porcine hind legs served as biological proxies for human lower extremities, with soft tissues removed except for key knee ligaments and menisci. The specimens were fixed at the proximal femur, and the impactor struck the tibia 5 mm below the knee joint level to replicate bumper-height impacts. Six strain gages were bonded directly to the cortical bone of the femoral diaphysis at heights of 90, 100, and 110 mm above the knee to measure dynamic responses. Tests were conducted with impacts directed toward both the lateral and medial sides of the leg. The results indicated that compressive strains occurred on the medial side of the femur, while tensile strains were observed on the lateral side. Maximum strain values increased linearly with height from the knee joint, with higher strains recorded in regions nearer to the proximal end. At lower and middle measurement heights, medial strains exceeded lateral strains, though values equalized at the highest point. This asymmetry persisted regardless of impact direction, attributed to the unsymmetrical structure of the lower extremity, specifically the fibula’s role in absorbing lateral impact loads. The mean input impact load was 1.9 kN, which caused no macroscopic damage but allowed for quantitative fracture risk prediction. The study concludes that directly measuring dynamic cortical bone strain is an effective method for elucidating injury mechanisms and predicting fracture risks in biological tests. The linear increase in strain toward the proximal femur aligns with cantilever bending moment principles, suggesting that while the femoral neck bears the highest theoretical stress, the femoral diaphysis is the likely site of fracture due to protective ligaments at the hip. These findings provide a validated experimental approach for improving pedestrian safety standards and understanding the specific biomechanical vulnerabilities of the lower extremity in side-impact scenarios.

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed.

Summary generated by qwen3.6-27b-prismaquant on 2026-06-26; verification: verified.

Topics

Ranked by relevance to this paper. Hover a topic for its definition.

• incidence prevalence