This study aimed to evaluate different fixation techniques and implants in oblique and biplanar chevron medial malleolar osteotomies using finite element analysis. Both oblique and biplanar chevron osteotomy models were created, and each osteotomy was fixed with two different screws (3.5 mm cortical screw and 4.0 mm malleolar screw) in two different configurations; (1) two perpendicular screws, and (2) an additional third transverse screw. Nine simulation scenarios were set up, including eight osteotomy fixations and the intact ankle. A bodyweight of 810.44 N vertical loading was applied to simulate a single leg stand on a fixed ankle. Sliding, separation, frictional stress, contact pressures between the fragments were analyzed. Maximum sliding (58.347µm) was seen in oblique osteotomy fixed with two malleolar screws, and the minimum sliding (17.272 µm) was seen in chevron osteotomy fixed with three cortical screws. The maximum separation was seen in chevron osteotomy fixed with two malleolar screws, and the minimum separation was seen in oblique osteotomy fixed with three cortical screws. Maximum contact pressure and the frictional stress at the osteotomy plane were obtained in chevron osteotomy fixed with three cortical screws. The closest value to normal tibiotalar contact pressures was obtained in chevron osteotomy fixed with three cortical screws. This study revealed that cortical screws provided better stability compared to malleolar screws in each tested osteotomy and fixation configuration. The insertion of the third transverse screw decreased both sliding and separation. Biplanar chevron osteotomy fixed with three cortical screws was the most stable model.
This is the author’s version of a work that was accepted for publication in The Journal of Foot and Ankle Surgery. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in The Journal of Foot and Ankle Surgery, ?, ?,, 2021 DOI: 10.1053/j.jfas.2021.07.017