Composite Bone Models in Orthopaedic Surgery Research and Education

Abstract

Composite bone models are increasingly used in orthopaedic biomechanics research and surgical education-applications that traditionally relied on cadavers. Cadaver bones are suboptimal for myriad reasons, including issues of cost, availability, preservation, and inconsistency between specimens. Further, cadaver samples disproportionately represent the elderly, whose bone quality may not be representative of the greater orthopaedic population. The current fourth-generation composite bone models provide an accurate reproduction of the biomechanical properties of human bone when placed under bending, axial, and torsional loads. The combination of glass fiber and epoxy resin components into a single phase has enabled manufacturing by injection molding. The high anatomic fidelity of the cadaver-based molds and negligible shrinkage properties of the epoxy resin results in a process that allows for excellent definition of anatomic detail in the cortical wall and optimized consistency of features between models. Recent biomechanical studies of composites have validated their use as a suitable substitute for cadaver specimens.Cadaver specimens have long been used in orthopaedic research and education specifically as well as medical education more broadly. 1 Biomechanical study of fracture fixation constructs and orthopaedic implants necessitates a substrate that reproduces the complex and anisotropic properties of organic human bone in order to produce clinically relevant insights. An accurate model of anatomy is also required in the educational setting for the instruction and practice of surgical technique. Accordingly, cadavers have remained a cornerstone of both research and education in orthopaedic surgery.Although cadaver specimens have distinct advantages in these settings, their use is complicated by a variety of factors. First, they are costly. Femurs, tibiae, and humeri-long bones commonly trialed in the biomechanical study of fracture fixation constructs-cost approximately $500 per specimen (Platinum Training, personal communication, 2013), compared with $170 for a fourth-generation composite equivalent. 2 A cadaver lower Dr. Elfar or an immediate family member has received research or institutional support from Synthes and Arthrex, and serves as a board member, owner, officer, or committee member of the American Society for Surgery of the Hand and the J. Robert Gladden Orthopaedic Society. None of the following authors or any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article: Mr. Menorca, Mr. Reed, and Dr. Stanbury. Logistical considerations also add cost to cadaver specimen use. Specimens must be preserved before, during, and after use. Freezing of fresh specimens is sometimes adequate but requires facility space and limits the duration and episodes of specimen use. 3 Use of traditional formalin-based embalming solutions may excessively stiffen soft tissues....

Biomechanical evaluation of a novel minimally invasive pedicle bone cement screw applied to the treatment of Kümmel’s disease in porcine vertebrae

“…To model osteoporosis, demineralization can be performed using reagents such as hydrochloric acid and hydrogen peroxide, but the models prepared using these methods differ from the pathological process of human osteoporosis, which is more like osteomalacia ( Elfar et al, 2014 ; Stewart et al, 2020 ). EDTA is a chelating agent that binds to the metal ion Ca 2+ and acts more slowly, preserving the natural biological structure of collagen better than the stronger and faster acting hydrochloric or nitric acids ( Lee et al, 2011 ).…”

Comparison of the fixation ability of headless compression screws and locking plate for metacarpal shaft transverse fracture

“…Because fresh cadaver metacarpal bones with similar bone strength are difficult to obtain, this study adopted artificial metacarpal bones for experiments by referring to a previous study [30] and a report published by the American Society for Testing and Materials. On the basis of previous experimental procedures, [31][32][33] we conducted cantilever bending tests to verify fixation effectiveness in which maximum fracture force and stiffness, 2 common indicators of fixation ability, [14,[33][34][35] were measured.…”

“…This study has several limitations. First, like most related studies, [30,31,33] we did not use fresh cadaver metacarpal bones but instead used artificial ones. Additionally, cantilever bending tests were conducted by referring to several studies.…”

Biomechanical analysis of a new cannulated screw for unstable femoral neck fractures

“…A study showed that the biomechanical properties of fourth-generation composite femurs under bending, axial and torsional loading were similar to those of cadaveric specimens, with less variability than that in cadaveric specimens ( Elfar et al, 2014 ). Referring to the efficacy analysis of Stoffel et al, 2017 ( Stoffel et al, 2017 ), we selected 10 Sawbone femurs (left, fourth generation, Pacific Research Laboratories, Washington, United States of America) to mimic a Pauwels type III femoral neck fracture.…”

“…A study showed that the biomechanical properties of fourthgeneration composite femurs under bending, axial and torsional loading were similar to those of cadaveric specimens, with less Frontiers in Bioengineering and Biotechnology frontiersin.org variability than that in cadaveric specimens (Elfar et al, 2014).…”