A minimally invasive percutaneous technique of intramedullary nail insertion in an animal model of fracture healing

Previous animal models of fracture repair have been shown to be reproducible but are often time-inefficient. We present a minimally invasive percutaneous technique for retrograde insertion of intramedullary pins in a model of rat femoral fracture healing. Forty Sprague-Dawley rats were divided into 3 groups: no fracture (n = 6), no fracture but pinned (n = 6), and fractured and pinned (n = 24). The pins were inserted in a percutaneous manner under fluoroscopic control. No incisions were made. All animals tolerated the procedure well and were using the operated leg within hours after the surgery. The mean time for the pinning procedure was 2.3 min (standard deviation 1.1 min). The mean fluoroscopic time for the first 15 procedures was 10 s (standard deviation 4.5 s). The mean fluoroscopic time for the last 15 procedures was 4.2 s (standard deviation 1.2 s). No patellar tendon ruptures or bleeding complications were seen in the postoperative period. The course of fracture healing was not altered by this new percutaneous technique of pin insertion.