Biomechanical advantage of low lateral hinge location in medial closing wedge distal femoral osteotomies.

• Main Author: Ong, Daniel Xing Xiang
• Other Authors: Chou Siaw Meng
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/167826
• Institution: Nanyang Technological University

Medial Closing-Wedge Distal Femoral Osteotomy (MCDFO) is a recognized medical procedure for managing lateral compartment cartilage injuries, degenerative conditions like knee osteoarthritis (OA), and genu valgum (knock-knee). However, there is a high incidence of Lateral Hinge Fracture (LHF) after MCDFO, resulting in complications and loss of correction. The hypothesis suggests that a lower hinge point, located under the metaphyseal flare and at the origin of the gastrocnemius tendon, can safeguard the hinge against lateral hinge fracture, as a result of the metaphyseal bone's properties. The overall objective of this project is to develop and design a fixture for comparative biomechanical testing to measure the strength of the remaining bone hinge at both the higher and lower hinge locations, to prevent Lateral Hinge Fracture (LHF). The study employs the use of 12 fresh goat femurs, and MCDFO is performed at either a lower or higher point. To quantitatively evaluate the resilience of the remaining bone hinge at these two distinct positions, a custom fixture was employed to secure the specimens at the distal femur, and they were attached to an Instron machine. The femoral diaphysis underwent cyclic loading, which caused the osteotomy gap to open and close repeatedly, and the maximum load sustained before hinge failure was measured to assess the hinge's capacity to resist failure. While premature cortical hinge fracture during specimen preparation prevented the hypothesis's validation, the periosteum's stiffness in the low hinge group was higher than the high hinge group, suggesting that even with cortical hinge failure, the periosteum of the low hinge group provided more support. The results provide valuable insights into the mechanical behavior of the lateral hinge and highlight the need for further research to investigate the impact of hinge location on preventing LHF in MCDFO.