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AIM: The Ilizarov external fixator (IEF) is frequently used in trauma and elective orthopaedics. Many of its biomechanical variables (ring size, wire diameter, wire number, half pins vs wires, etc.) and their influence on stability and stiffness have been investigated. There is, however, a paucity in the literature regarding the influence of the connecting rod numbers and configurations between the rings on IEF stability. The primary aim of this biomechanical study was to compare the stability between four- and three-rod IEF configurations. Secondarily to assess the difference in stability between symmetrical and asymmetrical spacing of the IEF rods. MATERIALS AND METHODS: A custom jig was designed to facilitate mounting of a basic two-ring IEF in a hydraulic press. Controlled centre and off-centre (thus simulated bending) axial loading was then applied across the frame. The configurations were loaded up to 4,000 N. The frame deformation was plotted and the data were then analysed and interpreted. RESULTS: Negligible differences were observed between different four- and three-rod configurations as long as the applied force at the loading point (LP) was within the area of support (AOS) created by the rods. The different four-rod constructs were always more stable than the three-rod constructs during bending. CONCLUSION: There is comparable stiffness between a four-rod and a three-rod IEF construct as long as the LP is within the AOS created by the rods. A four-rod IEF is stiffer than a three-rod IEF in bending. CLINICAL SIGNIFICANCE: This study will possibly change some paradigms regarding the planning and application of IEFs by Orthopaedics Traumatologists and Reconstruction Surgeons. HOW TO CITE THIS ARTICLE: Thiart G, Herbert C, Sivarasu S, et al. Influence of Different Connecting Rod Configurations on the Stability of the Ilizarov/TSF Frame: A Biomechanical Study. Strategies Trauma Limb Reconstr 2020;15(1):23-27.
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BACKGROUND: Injuries inflicted by gunshot wounds (GSWs) are an immense burden on the South African (SA) healthcare system. In 2005, Allard and Burch estimated SA state hospitals treated approximately 127 000 firearm victims annually and concluded that the cost of treating an abdominal GSW was approximately USD1 467 per patient. While the annual number of GSW injuries has decreased over the past decade, an estimated 54 870 firearm-related injuries occurred in SA in 2012. No study has estimated the burden of these GSWs from an orthopaedic perspective. OBJECTIVE: To estimate the burden and average cost of treating GSW victims requiring orthopaedic interventions in an SA tertiary level hospital. METHODS: This retrospective study surveyed more than 1 500 orthopaedic admissions over a 12-month period (2012) at Groote Schuur Hospital, Cape Town, SA. Chart review subsequently yielded data that allowed analysis of cost, theatre time, number and type of implants, duration of admission, diagnostic imaging studies performed, blood products used, laboratory studies ordered and medications administered. RESULTS: A total of 111 patients with an average age of 28 years (range 13 - 74) were identified. Each patient was hit by an average of 1.69 bullets (range 1 - 7). These patients sustained a total of 147 fractures, the majority in the lower extremities. Ninety-five patients received surgical treatment for a total of 135 procedures, with a cumulative surgical theatre time of >306 hours. Theatre costs, excluding implants, were in excess of USD94 490. Eighty of the patients received a total of 99 implants during surgery, which raised theatre costs an additional USD53 381 cumulatively, or USD667 per patient. Patients remained hospitalised for an average of 9.75 days, and total ward costs exceeded USD130 400. Individual patient costs averaged about USD2 940 (ZAR24 945) per patient. CONCLUSION: This study assessed the burden of orthopaedic firearm injuries in SA. It was estimated that on average, treating an orthopaedic GSW patient cost USD2 940, used just over 3 hours of theatre time per operation, and necessitated a hospital bed for an average period of 9.75 days. Improved understanding of the high incidence of orthopaedic GSWs treated in an SA tertiary care trauma centre and the costs incurred will help the state healthcare system better prioritise orthopaedic trauma funding and training opportunities, while also supporting cost-saving measures, including redirection of financial resources to primary prevention initiatives.