Proximal tibial strains following unicompartmental knee arthroplasty (UKA) : a finite element study

• Main Author: Muhammad Hidayat Salleh
• Other Authors: Chou Siaw Meng
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/54131
• Institution: Nanyang Technological University

Stress fracture on the medial tibia plateau following unicompartmental knee arthroplasty (UKA) has been reported for years yet the reason for such occurrences has not been fully understood. Previous indications show that the strength of the tibia was compromised and the support beneath the implant has deteriorated due to UKA but the origin of such failure is still being studied. This project examined the stress distribution on the proximal tibia following UKA via finite element analysis. Investigations were carried out on how pinholes and extended saw-cuts affect the stress distribution on the medial tibial plateau. Parametric variables include varying the height of the pinholes to the L-cut edge, depth of the pinholes, horizontal distance between the pinholes and the depth of extended sagittal saw-cut. From the results obtained, it was found that the model with shortest pinhole depth of 18 mm has the lowest stress at the regions in the pinholes. It is also found that the highest level of stress is found at the top edge of the web cut directly in contact with the implants. The results also showed that fracture was most probable with the extended sagittal saw-cut, increasing the probability with a deeper cut. In addition to fracture, loosening may also occur from cutting error. Hence utmost care has to be taken during UKA procedures to perform the cut with accuracy. Further work may include re-examining of constraints and interaction applied between implants and tibia, methods of prevention of loosening of implants, replacing the web cut, effects of extended-sloped saw-cut and validation of the model.