Assessment of the initial viscoelastic properties of a critical segmental long bone defect reconstructed with impaction bone grafting and intramedullary nailing

• Published in: Medical engineering & physics 2014-01, Vol.36 (1), p.39-48
• Main Authors: Costi, John J, Stanley, Richard M, Ding, Boyin, Solomon, Lucian B
• Format: Article
• Language: English
• Subjects: Animals; Bending stiffness; Biomechanical testing; Bone allograft; Bone Nails; Bone Transplantation; Compression stiffness; Elasticity; Fixation stability; Fracture Fixation, Intramedullary - instrumentation; Fracture stability; Impaction bone grafting; Materials Testing - instrumentation; Materials Testing - methods; Phase angle; Radiology; Segmental defect; Sheep; Tibia; Tibia - injuries; Tibia - surgery; Torsion stiffness; Viscosity
• ISSN: 1350-4533; 1873-4030
• DOI: 10.1016/j.medengphy.2013.09.003

Abstract Introduction This study compared the initial viscoelastic properties of a segmental tibial defect stabilized with intramedullary nailing and impaction bone grafting to that of a transverse fracture stabilized with intramedullary nailing. Materials and methods Seven sheep tibiae were tested in compression (1000 N), bending and torsion (6 Nm) in a six degree-of-freedom hexapod robot. Tests were repeated across three groups: intact tibia (Intact), transverse fracture stabilized by intramedullary nailing (Fracture), and segmental defect stabilized with a nail and impaction bone grafting (Defect). Repeated measures ANOVA on the effect of group on stiffness/phase angle were conducted for each loading direction. Results The Intact group was significantly stiffer than the Fracture and Defect groups in bending and torsion ( p < 0.022 for both loading directions), and was marginal for the Defect group in compression ( p = 0.052). No significant differences were found between the Fracture and Defect groups ( p > 0.246 for all loading directions) for stiffness/phase angle. In compression and bending, phase angles were significantly greater for the Fracture and Defect groups compared to Intact ( p < 0.025), with no significant differences between groups in torsion ( p = 0.13). Sensitivity analyses conducted between the Fracture and Defect group differences found that they were not of clinical significance. Conclusion The initial properties of a segmental defect stabilized with intramedullary nailing and impaction bone grafting was not clinically significantly different to that of a transverse fracture stabilized with intramedullary nailing.