Angular position of proximal screw fixation during minimally invasive hallux valgus surgery in the sagittal plane

Minimally invasive surgery for hallux valgus correction has evolved from early techniques, which used minimal or no hardware, to the current generation of more advanced, fixated osteotomies. These modern techniques often incorporate various forms of fixation, with recommendations on screw placement to optimize outcomes. Specifically, it is recommended that the proximal screw in the transverse plane should purchase two cortices of the first metatarsal to ensure maximum stability. While the ideal position of the screw in the anteroposterior view has been well documented in the literature, there is limited information available regarding the optimal parameters for fixation in the lateral view. The primary aim of this retrospective study is to examine the angular position of the proximal fixation screw in relation to the mechanical axis of the first metatarsal in the sagittal plane, based on radiographic analysis. In addition, the study reviews complications associated with hardware placement in this plane, providing critical insights for surgeons performing minimally invasive surgery for bunion correction. A total of 49 radiographs from 38 patients who met the inclusion criteria were analyzed. The mean angular position of the proximal screw with respect to the mechanical axis of the first metatarsal in the sagittal plane was determined to be 4.75 ± 4.17 degrees. Additionally, the secondary outcome, measuring the angle of the proximal screw in relation to the weight-bearing surface, was found to be 19.5 ± 8 degrees. These findings offer valuable guidance for preoperative planning and intraoperative fixation placement to avoid complications like metatarsal explosion.