Radiation Exposure and Safety in Minimally Invasive Foot and Ankle Surgery: A Comparative Analysis Between Minimally Invasive Distal First Metatarsal Transverse Osteotomy and Akin Osteotomy vs. Open Modified Lapidus Procedure

Abstract

Category: Midfoot/Forefoot, Bunion Diabetes

Keywords: Ankle, Degenerative, Hindfoot Deformity

Introduction/Purpose: Intraoperative fluoroscopy has become essential in orthopedic surgery, particularly with the rise of minimally invasive surgery (MIS) techniques. Despite the advantages of minimally invasive foot and ankle surgery, it raises concerns about radiation exposure to both patients and surgical staff. The purpose of this study was to evaluate fluoroscopy time and radiation dose (cumulative air kerma) associated with open versus MIS bunion correction, comparing the open modified Lapidus procedure and the minimally invasive distal first metatarsal transverse osteotomy and akin osteotomy (META). It was hypothesized that the META procedure would be associated with increased radiation dose and fluoroscopy time compared to the open modified Lapidus procedure.

Methods: A retrospective review was conducted for patients who underwent bunion surgery between January 2021 and June 2025 by two fellowship-trained orthopedic foot and ankle surgeons at a single academic institution. A total of 294 patients met inclusion criteria. Of these, 258 patients underwent a META procedure and 36 underwent an open modified Lapidus procedure. Fluoroscopy time (minutes) and radiation dose (mGy) were compared between groups.

Results: A mean fluoroscopy time of 2.13±1.27 (range, 0.06-7.05) minutes and a radiation dose of 2.02±1.30 (range, 0.05-7.52) mGy were observed in the META cohort. An average fluoroscopy time of 1.63±1.83 (range, 0.08-7.70) minutes and a radiation dose of 1.31±1.43 (range, 0.07-5.98) mGy were observed in the open modified Lapidus cohort. There was no significant difference in fluoroscopy time between cohorts (p=0.123), however the META group demonstrated a higher radiation dose than the open modified Lapidus group (p=0.007).

Conclusion: The META procedure had a significantly higher radiation dose compared to the open modified Lapidus procedure, though both remain substantially below the International Commission on Radiological Protection (ICRP) recommended occupational exposure of less than 20.00 mSv per year. Despite the META procedure generating an average radiation dose of 2.02 mGy per case, surgeons receive only 0.50% of the dose, thus, nearly 1,980 procedures would be required to exceed the 20.00 mSv annual occupational limit. These findings suggest that concerns about radiation exposure should not necessarily deter providers from performing the META technique for bunion correction.