Functionally graded 3D printed plates for rib fracture fixation

• Published in: Clinical biomechanics (Bristol) 2024-01, Vol.111, p.106151-106151, Article 106151
• Main Authors: Gupta, Richa, Judkins, Lauren, Friday, Chet S, Ulsh, Joseph B, Kovach, 3rd, Stephen J, Mehta, Samir, Tomonto, Charles, Manogharan, Guha, Hast, Michael W
• Format: Article
• Language: English
• Subjects: Biomechanical Phenomena; Bone Plates; Bone Screws; Fracture Fixation; Fracture Fixation, Internal; Humans; Printing, Three-Dimensional; Rib Fractures - surgery; Ribs
• ISSN: 0268-0033; 1879-1271; 1879-1271
• DOI: 10.1016/j.clinbiomech.2023.106151

Design freedom offered by additive manufacturing allows for the implementation of functional gradients - where mechanical stiffness is decreased along the length of the implant. It is unclear if such changes will influence failure mechanisms in the context of rib fracture repair. We hypothesized that our novel functionally graded rib implants would be less stiff than controls and decrease occurrence of secondary fracture at implant ends. Five novel additively manufactured rib implants were tested along with a clinically used Control implant. Fracture reconstructions were modeled with custom synthetic rib bones with a transverse B1 fracture. Ribs were compressed in a cyclic two-point bend test for 360,000 cycles followed by a ramp to failure test. Differences in cyclic stiffness, 3D interfragmentary motions, ramp-to-failure stiffness, maximum load, and work to failure were determined. The Control group had lower construct stiffness (0.76 ± 0.28 N/mm), compared to all novel implant designs (means: 1.35-1.61 N/mm, p