CT assessment of torsion following locked intramedullary nailing of tibial fractures. C.V.R. Prasad a, *, Mohamed Khalid a , P. McCarthy b , M.E. O'Sullivan a a Department of Orthopaedics, Merlin Park Regional and University College hospitals, Galway, Co. Galway, Ireland b Department of Radiology, University College Hospital,Galway, Co. Galway, Ireland Received 26 April 1998; accepted 9 February 1999 Abstract The aim of our study is to determine the incidence and extent of torsional malalignment in patients with tibial diaphyseal fractures treated with closed antegrade intramedullary (IM) nailing. We measured torsion using CT scanning in 22 patients. A dierence of 88 or more was found in 8 cases (36%) as compared with the uninjured side. Only 2 of these cases could be clinically detected and only one patient noted the problem. We also describe a method of directly calculating torsion from CT images captured on a single ®lm that is easy and does not require any special equipment. # 1999 Elsevier Science Ltd. All rights reserved. 1. Introduction Tibial torsion is de®ned as the physiologic twist of the proximal versus the distal articular axis of the tibial bone in the transverse plane [12,13]. An exagger- ation of this, either in the internal or external direc- tions is torsional malalignment and is known to occur after treatment of tibial shaft fractures by various means including closed IM nailing [3,7,8]. Clinical methods grossly underestimate the presence and/or the extent of torsional malalignment [2,10,15]. CT scan- ning is presently the investigation of choice [5]. Uncorrected tibial torsional malalignment is associated with knee and ankle osteoarthrosis [10,18,19], patello- femoral instability [6], patellar compression syndrome [11], pes planus [20] and gait abnormalities [20]. Therefore, we recommend that torsional deformity be considered a possible cause for less than optimal results following IM nailing for tibial shaft fractures and the problem be further investigated with CT Scanning. 2. Patients and methods Twenty two patients had their isolated tibial frac- tures treated with a Russell±Taylor delta IM nail. Fourteen of them were right tibiae and eight were left. The fractures were classi®ed using the AO classi®- cation (Table 1). The patients were positioned on the fracture table and skeletal traction applied through a Steinman pin in the os calcis. The second ray was aligned with the patella and the anterior superior iliac spine. The medullary canal was prepared and an appropriate size nail ®tted and locked proximally and distally except in patients 1, 5 and 11, which were locked only proximally. All patients were mobilised non-weight-bearing initially and then partially weight- bearing until clinical and radiological union and then mobilised full weight-bearing. 21 of these were done within one week of sustaining the injury. One patient (No. 6) had a Gustilo III open fracture that was in- itially treated with an external ®xator in another insti- tution and was converted to an IM nail after 2 months by us. Two patients had revision nailing for non-union at 11 and 14 months, taking the total to 24 IM nail- ings. All the patients were operated on by the senior surgeon (MO'S). None of these patients had any pre- Injury, Int. J. Care Injured 30 (1999) 467±470 0020-1383/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved. PII: S0020-1383(99)00132-1 www.elsevier.com/locate/injury * Corresponding author. Tel.: +353-91-524-222; fax: +353-91-756- 320.