Abstract
Introduction: In a new external fixation system for tibial fractures, accurate reduction was achieved with a complex temporary device, the Staffordshire Orthopaedic Reduction Machine (STORM) following which the fracture was fixed using a simple titanium bar fixator (IOS). The fixator was designed to allow controlled bending to optimise movement at the fracture site for callus growth. Ideal mechanical properties are approached: elastic return is to the reduced position; epicentric placement minimises shear and distraction on weightbearing. Integral healing assessment measures bending stiffness. The device is single-use.
Methods: Closed or grade I compound unstable tibial shaft fractures in 38 patients were externally fixed using the STORM in the operating theatre to reduce the fracture prior to application of an IOS fixator. Immediate full weight-bearing was encouraged. Bending characteristics of the fixator allowed 1 mm of axial movement for 20 kg loading. Fixator removal time was determined by fracture stiffness measurements against which the integral IOS stiffness measurement was compared.
Results: Mean healing time was 18.1 weeks, shortest time 9.5 weeks. The healing endpoint was fixator removal at a bending stiffness of 15 Nm/deg in two orthogonal axes. There was no subsequent creep or re-fracture. Good reduction, defined as less than 3 deg of maximum angulation and less than 3 mm of maximum translation, was achieved and maintained.
Discussion: The IOS/STORM system allows safe and effective treatment of tibial shaft fractures. With the fracture reduced, the external fixator screws can be placed in optimum positions. Good reductions were achieved and maintained. The IOS bending characteristics appear to approach the optimum for callus growth. The simple integral fracture stiffness measurement method has been validated against more complex devices.
Correspondence should be addressed to BLRS c/o BOA, at the Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London, WC2A 3PE, England.
