Comparative biomechanical study of different screw fixation methods for minimally invasive hallux valgus surgery: A finite element analysis.

BACKGROUND There are different screw configurations utilised for minimally invasive hallux valgus (HV) deformity despite limited biomechanical data assessing the stability and strength of each construct. We aimed to compare the strength of various screw configurations for minimally invasive HV surgery using finite element analysis (FEA). METHODS A FEA model was developed from a CT of a female with moderate HV deformity. Five screw configurations utilizing one or two bicortical or intramedullary screws were tested. Stress analysis considered osteotomy displacement, maximum and minimum principal stresses, and von Mises stress for both implants and bone for each screw configuration. RESULTS Fixation with two screws (one bicortical and one intramedullary) demonstrated the lowest values for osteotomy displacement, minimum and maximum total stress, and equivalent von Mises stress on the bone and screws in both loading conditions. CONCLUSION The optimal configuration when performing minimally invasive surgery for moderate HV is one bicortical and one intramedullary screw. LEVEL OF EVIDENCE Level III.