ABSTRACT
OBJECTIVE: This study was designed to compare the accuracy, time, and radiation exposure during the insertion of intramedullary nail locking screws using either standard fluoroscopic assistance or an electromagnetic (EM)-based navigational system without fluoroscopy. DESIGN: Prospective. SETTING: Level I academic trauma center. METHODS: Patients were divided into 2 groups: group 1 (fluoroscopic assistance), consisted of standard freehand fluoroscopically assisted insertion of locking screws (OEC 9900; G.E. HealthCare, Waukesha, WI), whereas group 2 (EM), consisted of EM navigationally assisted insertion without fluoroscopy (SureShot; Smith & Nephew, Memphis, TN). Technician arrival time, setup (SU) time, screw insertion (SI) time (seconds), fluoroscopy time (seconds), radiation exposure (mrads), and accuracy (hit or miss) were recorded for each screw. For group 1, the SU time was recorded as the time and radiation required to obtain "perfect circles" before insertion, and for group 2, the SU time was recorded as the time required to set up the navigational EM unit. Data collected regarding SI were then compared using standard analysis of variance. RESULTS: Forty-one locking screws were inserted in group 1, whereas 60 screws were inserted in group 2. Accuracy was 100% for both groups. For group 1, mean technician wait time was 77 seconds plus a mean perfect circle SU time of 105 seconds (9.2 mrads and 10 seconds of fluoroscopy). Mean SU time for group 2 was 94 seconds (no fluoroscopy). Mean insertion time was 342 seconds per screw for group 1 (32.9 mrads and 18 seconds of fluoroscopy) compared with 234 seconds per screw for group 2 (no fluoroscopy). These differences were statistically significant (P = 0.006). CONCLUSIONS: The use of EM navigation (SureShot; Smith & Nephew) for the insertion of intramedullary nail locking screws demonstrated accuracy similar to conventional fluoroscopic-guided insertion. However, EM-guided locking SI resulted in a significantly shorter total procedural time and completely eliminated radiation exposure. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
