Distal locking using an electromagnetic field-guided computer-based real-time system for orthopaedic trauma patients

OBJECTIVES: To compare the efficacy of distal interlocking during intramedullary nailing using a freehand technique versus an electromagnetic field real-time system (EFRTS). DESIGN: A prospective, randomized controlled trial. SETTING: Level I academic trauma center. PATIENTS/PARTICIPANTS: Patients older than 18 years who sustained a femoral or tibial shaft fracture amenable to antegrade intramedullary nailing were prospectively enrolled between August 2010 and November 2011. Exclusion criteria included injuries requiring retrograde nailing and open wounds near the location of the distal interlocks (distal third of the femur, knee, or distal tibia). INTERVENTION: Each patient had 2 distal interlocking screws placed: one using the freehand method and the other using EFRTS. MAIN OUTCOME MEASUREMENT: Techniques were compared on procedural time and number of interlocking screw misses. Two time points were measured: time 1 (time to find perfect circles/time from wand placement to drill initiation) and time 2 (drill initiation until completion of interlocking placement). RESULTS: Twenty-four tibia and 24 femur fractures were studied. EFRTS proved faster at times 1 and 2 (P < 0.0001 and P < 0.0002) and total time (P < 0.0001). This difference was larger for junior residents, though reached statistical significance for senior residents. Senior residents were faster with the freehand technique compared with junior residents (P < 0.004), but the 2 were similar using EFRTS (P = 0.41). The number of misses was higher with free hand compared with EFRTS (P = 0.02). CONCLUSION: These results suggest that EFRTS is faster than the traditional freehand technique and results in fewer screw misses. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.