title: Biomechanical evaluation of proximal tibial behavior following unicondylar knee arthroplasty: modified resected surface with corresponding surgical technique.
abstract: Persistent pain and periprosthetic fracture of the proximal tibia are troublesome complications in modern unicondylar knee arthroplasty (UKA). Surgical errors and acute corners on the resected surface can place excessive strains on the bone, leading to bone degeneration. This study attempted to lower strains by altering the orthogonal geometry and avoiding extended vertical saw cuts. Finite element models were utilized to predict biomechanical behavior and were subsequently compared against experimental data. On the resected surface of the extended saw cut model, the greatest strains showed a 50% increase over a standard implant; conversely, the strains decreased by 40% for the radial-corner shaped model. For all UKA models, the peak strains below the resection level increased by 40% relative to an intact tibia. There was no significant difference among the implanted models. This study demonstrated that a large increase in strains arises on the tibial plateau to resist a cantilever-like bending moment following UKA. Surgical errors generally weaken the tibial support and increase the risk of fractures. This study provides guidance on altering the orthogonal geometry into a radial-shape to reduce strains and avoid degenerative remodeling. Furthermore, it could be expected that predrilling a posteriorly sloped tunnel through the tibia prior to cutting could achieve greater accuracy in surgical preparations.
authors: Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan.
authors: Tsung-Wei
authors: TW
authors: Chang
authors: Chan-Tsung
authors: CT
authors: Yang
authors: Yu-Liang
authors: YL
authors: Liu
authors: Wen-Chuan
authors: WC
authors: Chen
authors: Kun-Jhih
authors: KJ
authors: Lin
authors: Yu-Shu
authors: YS
authors: Lai
authors: Chang-Hung
authors: CH
authors: Huang
authors: Yung-Chang
authors: YC
authors: Lu
authors: Cheng-Kung
authors: CK
authors: Cheng
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D020342:Finite Element Analysis; D055595:Mechanical Phenomena; D019300:Medical Errors; D008953:Models, Anatomic; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D013977:Tibia / Q000601:surgery*; D016896:Treatment Outcome