title: Biomechanical comparison of locking plate and crossing metallic and absorbable screws fixations for intra-articular calcaneal fractures.
abstract: The locking plate and percutaneous crossing metallic screws and crossing absorbable screws have been used clinically to treat intra-articular calcaneal fractures, but little is known about the biomechanical differences between them. This study compared the biomechanical stability of calcaneal fractures fixed using a locking plate and crossing screws. Three-dimensional finite-element models of intact and fractured calcanei were developed based on the CT images of a cadaveric sample. Surgeries were simulated on models of Sanders type III calcaneal fractures to produce accurate postoperative models fixed by the three implants. A vertical force was applied to the superior surface of the subtalar joint to simulate the stance phase of a walking gait. This model was validated by an in vitro experiment using the same calcaneal sample. The intact calcaneus showed greater stiffness than the fixation models. Of the three fixations, the locking plate produced the greatest stiffness and the highest von Mises stress peak. The micromotion of the fracture fixated with the locking plate was similar to that of the fracture fixated with the metallic screws but smaller than that fixated with the absorbable screws. Fixation with both plate and crossing screws can be used to treat intra-articular calcaneal fractures. In general, fixation with crossing metallic screws is preferable because it provides sufficient stability with less stress shielding.
authors.affiliation: Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065, China.|Pudong New Area People's Hospital, Shanghai, 201299, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Ni
authors.affiliation: Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: Duo Wai-Chi
authors.initials: DW
authors.lastname: Wong
authors.affiliation: Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065, China.
authors.forename: Jiong
authors.initials: J
authors.lastname: Mei
authors.affiliation: Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065, China. niu@tongji.edu.cn.|Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), Shanghai, 201619, China. niu@tongji.edu.cn.
authors.forename: Wenxin
authors.initials: W
authors.lastname: Niu
authors.affiliation: Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D002102:Cadaver; D002111:Calcaneus / Q000000981:diagnostic imaging / Q000293:injuries* / Q000503:physiopathology; D003198:Computer Simulation; D020342:Finite Element Analysis; D005592:Fracture Fixation / Q000295:instrumentation* / Q000379:methods; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D016059:Range of Motion, Articular; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed
keywords: absorbable screw; biomechanics; calcaneal fracture; finite-element analysis; in vitro experiment; plate fixation