Additively Manufactured Bone Surrogates for Reproducing Screw Insertion Behavior in Cadaveric Bone

Abstract

Reliable preclinical testing of orthopedic implants in osteoporotic bone remains challenging because cadaveric specimens show substantial inter-specimen variability and limited availability [1]. This is particularly problematic for screw-based fixation, where local bone architecture strongly affects anchorage and insertion behavior. Bone surrogates therefore offer considerable potential for establishing more reproducible test environments [2-3].

The present study investigates whether additively manufactured bone surrogates can reproduce the screw insertion behavior of osteoporotic cadaveric bone. First, instrumented screw insertion tests were performed on cadaveric bone from aged body donors, using the distal radius as an example application, in order to characterize the characteristic torque–angle response during screw insertion. Then, surrogate specimens were manufactured by stereolithography from a rigid photopolymer resin, with solid regions at the top and bottom representing cortical bone and a lattice-based trabecular architecture with varying relative densities in between. The same screw insertion experiments were then performed on the printed specimens using a dedicated test bench, and the resulting torque–angle curves were compared with the cadaveric reference and analytical model predictions.

The additively manufactured surrogates exhibited torque–angle profiles with similar curve morphology to those observed in osteoporotic cadaveric bone. Quantitative parameters derived from the insertion process, including peak torque and torque rise characteristics, also showed close agreement. These findings support the development of patient- and disease-specific bone surrogates for more reproducible preclinical evaluation of orthopedic implants.

[1]   Oldham, Blaine, et al. "The current state of biomechanical analyses of the adult human femur: A systematic review." Journal of the Mechanical Behavior of Biomedical Materials(2025): 107158.

[2]   Hollensteiner, Marianne, Andreas Traweger, and Peter Augat. "Anatomic variability of the human femur and its implications for the use of artificial bones in biomechanical testing." Biomedical Engineering/Biomedizinische Technik 69.6 (2024): 551-562.

[3]   Zdero, Radovan, Pawel Brzozowski, and Emil H. Schemitsch. "Biomechanical properties of artificial bones made by Sawbones: a review." Medical engineering & physics 118.1 (2023): 104017.