Title : Biomechanical characteristics analysis of Sanders type II and III calcaneal fractures fixed by open reduction and internal fixation and percutaneous minimally invasive fixation
Abstract:
Background:
This study explored the biomechanical variances between open reduction and internal fixation (ORIF) and percutaneous minimally invasive fixation (PMIF) in addressing Sanders type II and III calcaneal fractures. These differences were examined utilizing finite element analysis, providing insights into the mechanical performance of each surgical approach.
Methods:
Utilizing computed tomography (CT) images of the human foot and ankle, key anatomical landmarks—the sustentaculum tali, anterior process, and calcaneal tuberosity—were identified and stabilized in accordance with the three-point fixation principle. Based on these landmarks, three-dimensional finite element models were constructed to represent Sanders type II and III calcaneal fractures, treated with both open reduction and internal fixation (ORIF) and percutaneous minimally invasive fixation (PMIF). To mimic balanced standing, constraints were applied to the proximal surfaces of the tibia, fibula, and surrounding soft tissues. Additionally, loads representing ground reaction force and Achilles tendon force were incorporated into the model.
Results:
The finite element analysis revealed maximum stress values of 81.23 MPa, 199.29 MPa, and 113.88 MPa on the calcaneus, screws, and plates, respectively, in the ORIF group. In comparison, the PMIF group exhibited maximum stresses of 70.02 MPa and 209.46 MPa on the calcaneus and screws, respectively. Regarding displacement, the ORIF group displayed maximums of 0.21 mm, 0.22 mm, and 0.14 mm on the calcaneus, screws, and plates, while the PMIF group showed 0.20 mm and 0.14 mm on the calcaneus and screws, respectively. Notably, all these values remained within the allowable stress and elastic deformation limits of the materials used, indicating no substantial stress concentration. When repairing Sanders type II and III calcaneal fractures, both the maximum stress and displacement were marginally lower in the PMIF group compared to the ORIF group.
Conclusions:
This study offers valuable insights that can guide the refinement of implant designs, the creation of tailored preoperative strategies, and the selection of optimal surgical techniques.
Key Words:
Calcaneal fracture, Biomechanics, Sander classification, Internal fixation, Finite element analysis
