Biomechanical study of minimally invasive correction of hallux valgus fixation with absorbable screws: A finite element analysis

Abstract

AbstractBackground Absorbable screws have been applied in clinical practice for the treatment of minimally invasive hallux valgus, but most of the available publications are the results of clinical follow-up, lacking the related biomechanical studies. The aim of this study was to evaluate mechanical responses and stabilities of absorbable screws fixation after the distal metatarsal osteotomy in hallux valgus treatment. Methods In this study, the finite element method was used to construct models of hallux valgus fixation with hallux valgus angles of 30° and 40° using one or two 2.7mm and 4.5mm absorbable screws after osteotomy. Then, the stress of the materials in the bone, the anti-rotation performance, and the inter-fragmentary strain (IFS) results were analyzed by finite element analysis. Results The stress results for the two fixing methods with hallux valgus angles of 30° and 40° under the two working conditions are within the safe range under all conditions. It was also found that the screws had excellent anti-rotation performance whether the osteotomy fragment was fixed with two 2.7mm or one 4.5mm absorbable screws. All the results of inter-fragmentary strain are in the range between 0.9% and 11% which is suitable for bone healing. Conclusions The results indicate that using two 2.7mm screws or one 4.5mm screw to fix the first metatarsal minimally invasive osteotomy can both achieve satisfactory mechanical effect. There was not much difference in the simulation effect between the two fixation methods, and either method can be selected indiscriminatingly in clinical application.