CT scanogram for limb length discrepancy in comminuted femoral shaft fractures following IM nailing Rahul Vaidya, Brent Anderson, Ashraf Elbanna, Robert Colen, Daniel Hoard, Anil Sethi * Department of Orthopedics, Detroit Receiving Hospital, Detroit, MI 48201, USA Locked intramedullary nailing (IMN) is the preferred method for treating femoral shaft fractures. 1,2 IMN has a high rate of fracture union reported to be 99% and an infection rate as low as 1%. 3 Leg length discrepancy (LLD) following IMN of femoral shaft fractures is not uncommon. Although there are methods described to avoid this complication intra-operatively, including the use of a sterile Bovie cord or radiopaque ruler, 4 LLD may still occur in up to 43% of cases. 5 LLD is more common in fractures that are severely comminuted as the bony landmarks are lost. Winquist and Hansen found an incidence of LLD in 14.8% of type III and 22.8% of type IV fractures in their series. 3 LLD may cause unsightly gait abnormalities, lead to degenera- tive arthritis of the lower extremity or lumbar spine and may become a source of litigation after surgery. 6–8 To prevent these complications, it is imperative that postoperative limb length inequality be recognised early and corrected if deemed to be unacceptable. The degree of LLD that requires correction remains undefined. Winquist et al. 3 accepted up to 1.5 cm LLD in younger patients and up to 2.5 cm LLD in patients older than 65 years. Numerous methods have been described to assess limb length including a clinical examination and imaging modalities that comprise plain radiography, computed radiography, micro-dose digital radiography, ultrasonography, computerised tomography (CT) and magnetic resonance and imaging (MRI). 9 A recent report has highlighted the high accuracy and reliability of a CT scanogram in limb length measurements. 10 Further, CT scanogram has been reported to have comparable costs as plain radiographs with less gonadal radiation. 9,11 The purpose of this study was to investigate the suitability of routinely obtaining a CT scanogram postoperatively on patients with comminuted Winquist III and Winquist IV (AO/OTA type C1, C2 and C3) femoral shaft fractures treated with IMN and to Injury, Int. J. Care Injured 43 (2012) 1176–1181 A R T I C L E I N F O Article history: Accepted 26 March 2012 Keywords: Femur Leg length Fracture Scanogram A B S T R A C T Introduction: Leg length discrepancy (LLD) following intramedullary nailing of femoral fractures is not uncommon. We designed a prospective study to evaluate the efficacy of routine postoperative computed tomography (CT) scanograms for evaluation of limb length discrepancy in patients with comminuted Winquist III or IV femoral shaft fractures treated with intramedullary nailing. Methods: The study consisted of 15 patients with Winquist III and 13 with a Winquist IV femoral shaft fracture pattern with an average age of 37 years. The mechanisms of injury were motor vehicle collision (13), gunshot wound (12) and falls (three). All patients were treated with a statically locked intramedullary femoral nail (18 antegrade and 10 retrograde). A CT scanogram evaluated limb length in all patients. A discrepancy of greater than 20 mm was considered for correction during the same admission. An LLD of 15–20 mm was discussed with the patient extensively for correction. Results: In the 28 patients included in our study, the average limb length discrepancy was 9.1 mm with a range of À43.5 mm short to 10.3 mm long. The LLD was less than 10 mm in 18 patients (64%), 10–15 mm in four patients (14%), 15–20 mm in three patients (11%) and more than 20 mm in three patients (11%). Measurement of discrepancy as small as 0.5 mm showed that 18 patients were fixed with shortening and in 10 patients the operated femur was longer. Tibia lengths were also evaluated separately. Though none of the tibiae had a previous fracture, only three patients (10%) had tibiae of equal length. In 13 patients, an unequal tibia partially corrected the LLD whilst in 12 it added to the discrepancy. Five patients with LLD of greater than 15 mm underwent correction. Conclusions: A postoperative scanogram in patients with comminuted femoral shaft fractures treated with intramedullary nailing is useful to evaluate LLD and allows for early intervention. The ideal length where correction is necessary remains unclear. ß 2012 Elsevier Ltd. All rights reserved. * Corresponding author at: Department of Orthopedic Surgery, Detroit Receiving Hospital and University Health Center, 4201 St. Antoine Blvd. 4D-4, Detroit, MI 48201, USA. Tel.: +1 313 966 7852; fax: +1 313 966 8400. E-mail address: anilsethi09@gmail.com (A. Sethi). Contents lists available at SciVerse ScienceDirect Injury jo ur n al ho m epag e: ww w.els evier .c om /lo cat e/inju r y 0020–1383/$ – see front matter ß 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.injury.2012.03.022