Leg lengthening using intramedullay skeletal kinetic distractor: Results of 57 consecutive applications Mohamed Kenawey a,b, *, Christian Krettek a , Emmanouil Liodakis a , Ulrich Wiebking a , Stefan Hankemeier a a Trauma Department, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany b Orthopaedic Surgery Department, Sohag Faculty of Medicine, 82524 Sohag, Egypt During the last two decades, many developments were achieved in the field of limb lengthening surgery, in which the main goal was to increase patients’ acceptance and comfort during lengthening. One important achievement is the use of totally implantable intramedullary lengthening nails. 2,3,7,10,16 In 2001, Cole et al. 3 reported their first experience with their mechanically activated lengthening nail—the intramedullary skeletal kinetic distractor (ISKD). ISKD nail lengthens by rotations of 3–98 through a ratchet mechanism around the longitudinal axis of the nail. 3,9,10 Reported advantages of lengthening nails include elimination of external fixator-associated complications, earlier rehabilitation, reduced risk of deep infection, malalignment and refracture, reduced pain and more rapid return to normal joint motion and activity. 9,10,16 On the other hand, larger series of lengthening using ISKD nail had recently reported significant concerns and complica- tions, in particular with the distraction mechanism and the resulting poor control of the distraction rate. 13,14,16 Reports of non- distracting or runaway ISKD nails are now present with an incidence of up to 45%; however, all of these reported difficulties were in femoral lengthening. 13,14,16 Injury, Int. J. Care Injured xxx (2010) xxx–xxx ARTICLE INFO Article history: Accepted 21 June 2010 Keywords: Leg lengthening Intramedullary skeletal kinetic distractor (ISKD) Intramedullary lengthening Implantable lengthening nails Limb length discrepancy ABSTRACT Background: Mechanically activated intramedullary lengthening nails are advantageous over external fixator. However, difficulties with the control of the distraction rate are the main drawbacks, which may in turn cause insufficient bone regenerate. Patients and methods: A total of 57 lengthening procedures were performed using intramedullary skeletal kinetic distractor (ISKD) nail in 53 patients (femoral = 45 and tibial = 12). Average length gain was 4.3  1.6 cm. The cause of shortening was post-traumatic (n = 33), congenital (n = 20), post-tumour resection (n = 1), cosmetic femoral lengthening (n = 2) and post-correction of distal femoral varus deformity (n = 1). Results: The desired lengthening was achieved in all patients. The mean follow-up period was 23  12 months. The healing index for patients with normal bone healing was 1.2  0.32 months/cm. Complications in femoral lengthening were superficial wound infection (n = 1), premature consolidation (n = 4) and insufficient bone regenerate (n = 11), while in the tibial lengthening, two developed equinus contractures, one had compartment syndrome following implantation of the nail and one insufficient bone regenerate. Furthermore, nine runaway nails and three non-distracting nails were present in the femoral lengthening. One non-distracting nail responded to manipulation under anaesthesia, one required exchange nailing and accidental acute lengthening of 3 cm took place while manipulating the third nail. Patients with femoral lengthening and those with insufficient regenerate had significantly higher distraction rates (P = 0.006 and 0.003, respectively). Six out of the nine runaway nails developed insufficient bone regenerate. In addition, 10.7-mm tibial ISKD nails were found to have lower rates of runaway nails compared with other used diameters. Conclusion: We emphasise the rule of distraction rates above 1.5 mm/day in the development of insufficient bone regenerate. Distraction problems with these nails are mostly due to dysfunction within the ratcheting mechanism, which may be related to the diameter of the nail. New designs for mechanically activated nails with a better control mechanism for the distraction rate are required. ß 2010 Elsevier Ltd. All rights reserved. * Corresponding author at: Trauma Department, Hannover Medical School, Carl- Neuberg-Str. 1, 30625 Hannover, Germany. Tel.: +49 176 87216625; fax: +49 511 532 5877. E-mail address: mohamed_kenawey@yahoo.com (M. Kenawey). G Model JINJ-4321; No. of Pages 6 Please cite this article in press as: Kenawey M, et al. Leg lengthening using intramedullay skeletal kinetic distractor: Results of 57 consecutive applications. Injury (2010), doi:10.1016/j.injury.2010.06.016 Contents lists available at ScienceDirect Injury journal homepage: www.elsevier.com/locate/injury 0020–1383/$ – see front matter ß 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2010.06.016