Forschung & Innovation
Publikationen
From load-bearing to load-sharing
PMU Autor*innen
Marianne Hollensteiner, Markus Greinwald, Mischa Muhling, Dirk Baumeister, Peter Augat
Alle Autor*innen
Marianne Hollensteiner, Martina Schindler, Markus Greinwald, Mischa Muhling, Dirk Baumeister, Peter Augat
Fachzeitschrift
ARCHIVES OF ORTHOPAEDIC AND TRAUMA SURGERY
Kurzfassung
Locked plate osteosynthesis functions as an internal fixator, yet load-induced plate-bone and fragment-fragment contacts - key transitions from load-bearing to load-sharing - remain poorly characterized. This study quantified their effects on construct stiffness, plate strain, and interfragmentary motion under axial loading. Twenty-seven configurations were tested using epoxy-glass surrogate bone fixed with titanium LCP plates, varying fracture gap (3-9 mm), working length (49-121 mm), and plate-bone distance (0-3 mm). Digital image correlation measured strain and motion. Contact events were identified manually from characteristic transitions in the force-displacement response, supported by corresponding changes in plate-surface strain progression. Geometric parameters dominated initial stiffness (125-442 N/mm), decreasing with plate elevation and working length in elevated setups. Within the investigated load range up to 600 N, 16/27 configurations showed non-linear transitions associated with contact events: fragment-fragment contact caused pronounced stiffness increases and strain stagnation at the fracture gap, whereas plate-bone contact was associated with local plate-surface strain stagnation at the location overlying the contact while strain at the fracture gap continued to increase. Interfragmentary motion stagnated after contact, confirming contact-dependent shifts in load transfer. Response surface regression explained 81.9% of the variance in initial stiffness and 89.6% of the variance in axial interfragmentary motion, identifying outcome-specific associations with geometric parameters and selected interaction terms. In conclusion, load-dependent contact events were associated with distinct transitions in construct stiffness, plate-surface strain progression, and interfragmentary motion, complementing the observed associations between geometric parameters and initial mechanical behavior.
Keywords
CONSTRUCT STIFFNESS, INTERFRAGMENTARY MOTION, Bone contact, Bridge plating, Load-sharing, Locked plate osteosynthesis, Plate strain