688 ORTHOPEDICS | Healio.com/Orthopedics n tips & techniques Section Editor: Steven F. Harwin, MD Prevention of Cortical Breach During Placement of an Antegrade Intramedullary Femoral Nail John A. Scolaro, MD; Christina Endress, MD; Samir Mehta, MD T he average human femur has a radius of curvature between 114 and 120 cm. 1,2 Most commercially manu- factured femoral intramedul- lary implants have a radius of curvature between 150 and 300 cm, 3 and the intramedul- lary devices are straighter than the anatomic curvature of the femur. This mismatch is not often clinically significant during antegrade femoral nail- ing with a proper starting point and surgical technique in non- pathologic bone. Anterior cortical breach during nail placement is a rare occurrence. Ostrum and Levy 4 reported 3 cases of penetration of the distal femoral anterior cortex during intramedullary nailing of subtrochanteric fe- mur fractures. They suggested that fracture pattern and starting point, along with the femoral radius of curvature, may have contributed to this occurrence. 4 Pankaj et al 5 suggested that Poller screws (ie, “blocking” screws or cortical replacing screws) be used to deflect an intramedullary nail posteriorly and protect the anterior cortex of the femur when indicated. The diameter of such screws was noted to be a concern with- in the narrow metadiaphyseal region of the femur and, there- fore, could potentially be an is- sue with such a technique. 5 The current authors describe a technique that uses a modifi- cation of the concept of Poller screws to assist in the safe pas- sage of a femoral nail in the clinical scenario with excessive anterior bow to the femur and concern that a standard femoral intramedullary nail may not be able to be passed safely. This technique requires minimal soft tissue disruption, is performed percutaneously, requires only a basic Steinmann pin set and power driver, and leaves only small-diameter cortical defects along the anterior femur (even- tually bypassed with the intra- medullary nail). Not to be used frequently, it is a technique re- served for cases in which safe passage of the nail is in question because of the patient’s anato- my or the fracture pattern. It is not meant to compensate for an improper starting point or other technical error. CASE REPORT A 69-year-old woman re- ported right thigh pain. Her medical history was notable for obesity (height, 154.2 cm; weight, 84.4 kg; body mass index, 36.3), rickets, and hy- pertension, and her surgical history revealed prior gastric bypass surgery, bilateral total knee arthroplasty, and open reduction and internal fixation of a left periprosthetic femur fracture approximately 3 years previously. The patient noted intermittent achiness and dis- comfort in the right thigh with prolonged weight bearing. Radiographs demonstrated cortical hypertrophy along the medial aspect of the proximal femur at the junction of the subtrochanteric/diaphyseal border, consistent with a stress fracture (Figures 1, 2). Of note, the patient had no history of bisphosphonate use. Protected The authors are from the Department of Orthopaedic Surgery (JAS, CE); and the Orthopaedic Trauma & Fracture Service (SM), Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. The authors have no relevant financial relationships to disclose. Correspondence should be addressed to: Samir Mehta, MD, Orthopaedic Trauma & Fracture Service, Hospital of the University of Pennsylvania, 3400 Spruce St, 2 Silverstein Pavilion, Philadelphia, PA 19104 (samir.mehta@ uphs.upenn.edu). doi: 10.3928/01477447-20130821-03 Abstract: The radius of curvature of femoral intramedullary nails does not match the average radius of curvature of the hu- man femur. Anterior cortical breach of the distal femur during nail placement has been reported in certain fracture patterns, in femora with a smaller radius of curvature, and at the starting point of the nail. The authors describe a novel technique used to prevent anterior cortical disruption of the femur using multi- ple percutaneously placed Steinmann pins. This technique en- sures safe passage of medullary reamers and the femoral nail.