ORTHOPEDICS | Healio.com/Orthopedics n Feature Article abstract Full article available online at Healio.com/Orthopedics. Search: 20130624-26 Intramedullary nailing is one of the most convenient biological options for treating distal femoral fractures. Because the distal medulla of the femur is wider than the middle diaphysis and intramedullary nails cannot completely fill the intramedullary canal, intramedullary nailing of distal femoral fractures can be difficult when trying to obtain adequate reduction. Some different methods exist for achieving reduction. The purpose of this study was determine whether the use of blocking screws resolves varus or valgus and translation and recurvatum deformities, which can be encountered in antegrade and retrograde intramedullary nailing. Thirty-four patients with distal femoral fractures underwent intramedullary nailing be- tween January 2005 and June 2011. Fifteen patients treated by intramedullary nailing and blocking screws were included in the study. Six patients had distal diaphyseal fractures and 9 had distal diaphyseo-metaphyseal fractures. Antegrade nailing was performed in 7 patients and retrograde nailing was performed in 8. Reduction dur- ing surgery and union during follow-up were achieved in all patients with no signifi- cant complications. Mean follow-up was 26.6 months. Mean time to union was 12.6 weeks. The main purpose of using blocking screws is to achieve reduction, but they are also useful for maintaining permanent reduction. When inserting blocking screws, the screws must be placed 1 to 3 cm away from the fracture line to avoid from propaga- tion of the fracture. When applied properly and in an adequate way, blocking screws provide an efficient solution for deformities encountered during intramedullary nailing of distal femur fractures. The authors are from the Department of Orthopaedics and Traumatology (MS, FD, AG), Acibadem Kadikoy Hospital; the Department of Orthopaedics and Traumatology (SC), GATA Haydarpasa Hospital, Istanbul, Turkey; and Harris Orthopaedic Laboratory (SC), Massachuasetts General Hospital, Boston, Massachusetts. The authors have no relevant financial relationships to disclose. Correspondence should be addressed to: Selami Cakmak, MD, Harris Orthopaedic Laboratory, Massachusetts General Hospital, 55 Fruit St, Boston, MA 02114 (selamicakmak@gmail.com). doi: 10.3928/01477447-20130624-26 Blocking Screws for the Treatment of Distal Femur Fractures MUSTAFA SEYHAN, MD; SELAMI CAKMAK, MD; FERDI DONMEZ, MD; AREL GERELI, MD A Figure: Illustrations showing the use of blocking screws to correct recurvatum deformity on the sagittal plane. A blocking screw is placed on the large distal fragment anterior to the guidewire from the wide-angle corner (formed by fracture line with bone cortex) in a lateral to medial direction (A). When the nail is reapplied, reduction is mostly achieved (B). B e936