Evaluation of postoperative MRI in pediatric patients after orthopaedic hardware implantation

Abstract

Background: MRI is a valuable diagnostic tool in musculoskeletal imaging. However, concerns exist regarding MRI examinations in the presence of metallic implants, including loosening, heating, and migration of the implant, and magnetic field interactions. Few studies have discussed the safety of MRI in the presence of orthopaedic implants, particularly in the immediate postoperative period. This study aimed to evaluate the safety of MRI within 24 hr after orthopaedic hardware implantation and whether MRI may compromise the integrity of fixation. Methods: A retrospective chart review was performed at a single tertiary care pediatric hospital to identify patients who underwent postoperative MRI after hardware implantation (open reduction and femoral osteotomy) for the treatment of developmental dysplasia of the hip during the 6-year study period. Patient records and follow-up imaging were reviewed to assess time between implantation and postoperative MRI, magnetic field strength, implant type, and patient outcomes. Results: Twenty-eight patients (ages 6 mo to 5 yr) were included in this study, accounting for 32 postoperative MRIs. All MRIs were performed within 8 hr postoperatively (average time to MRI 131 min). Implants consisted of four-hole stainless steel plates and four screws in all patients. No complications were observed regarding implant migration, loosening, nonunion, compromised fixation, or thermal effects to soft tissues. Conclusions: To our knowledge, this is the largest cohort studied for the safety of postoperative MRIs, and the only exclusively pediatric study. Based on these findings, we conclude that orthopaedic implants can safely be imaged in the immediate postoperative period.