Reliable Method for Avoiding Malrotation Deformity After Intramedullary Nailing of Comminuted Femur Fractures: Clinical Validation of a Previously Described Technique

Abstract

To evaluate a previously described technique using the inherent anteversion of intramedullary nail (IMN) to avoid malrotation in comminuted femur fractures and describe the use of magnetic resonance imaging (MRI) as an alternative method for assessing postoperative femoral version. Prospective consecutive cohort study. Level I trauma center. Twenty-five consecutive patients with comminuted femur fractures (Winquist III/IV, OTA/AO 32-B/32-C) treated by a single surgeon with IMN between September 1, 2011, and February 28, 2015. IMN on a fracture table with intraoperative femoral version set by the inherent version of the implant. All patients received a postoperative computed tomography (CT) or MRI to assess femoral version. Mean difference in postoperative femoral anteversion (DFA) between injured limb and uninjured limb as measured by CT or MRI. Mean difference in postoperative femoral version of the injured femur from the inherent version of the implant (12 degrees) was measured with CT or MRI. The mean postoperative DFA was 9.1 ± 5.6 degrees. Postoperative DFA greater than 15 degrees was found in 2 (8.0%) patients. Mean difference in postoperative version of the injured femur from the inherent 12 degrees of the implant was 7.1 ± 5.4 degrees. Patients tolerated MRI studies well. Our previously described technique using the inherent anteversion of an IMN is effective and leads to a very low rate of malrotation, even in highly comminuted fractures. The technique is particularly useful in treating bilateral femur fractures. MRI can be used safely and effectively to assess anteversion after fixation of femur fractures. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.