In a novel external fixation system for tibial fractures accurate reduction is achieved with a complex temporary device (Staffordshire Orthopaedic Reduction Machine: STORM) following which the reduced fracture is fixed using a simple titanium bar fixator (IOS). With the fracture reduced, the external fixator screws may be placed in the optimum position. The fixator is designed to allow controlled bending to optimise movement at the fracture site for callus growth. With no need for adjustable elements, the fixator is small and short enough for epicentric placement in the commonest fracture of the middle and distal thirds. Optimum 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.

In 40 tibial fractures (closed or grade I compound) the mean healing time was 15 weeks with a healing endpoint of bending stiffness of 15Nm/deg in two orthogonal axes and full weightbearing on fixator removal with no subsequent creep or refracture. Good reduction, defined as less than 5 deg of maximum angulation and less than 3mm of maximum translation, was achieved and maintained. The incidence of pin site complications was extremely low and there were no deep infections.

This new device thus far has had few of the drawbacks commonly associated with external fixation. The infection rate is low, healing time is comparable to other methods and there have been no malunions. We feel our strict adherence to fracture reduction and pin site hygiene are the most important factors in producing these excellent results.

Introduction: We present a prospective comparative study of 200 consecutive patients of closed tibial shaft fractures treated by external fixation using two different fracture reduction methods. Factors affecting fracture healing, including the effect of quality of reduction, was studied.

Methods: The healing time for all these fractures was determined by a combination of clinical, radiological and fracture stiffness measurements. The effect of smoking, AO classification type, associated fractures, initial and final angulation and translation on healing time was evaluated using nonparametric tests and regression analysis.

Results: Healing time was affected most by presence of Compartment syndrome followed by smoking status and final translation at fracture site. Having a compartment syndrome significantly increased fracture healing time (mean 286.7 days versus 139.2 days). There was no difference in healing times between the two different reduction machines. Angulation was found not to affect healing time, but translation did. Both initial and final translation were better using STORM (Staffordshire Orthopaedic Reduction Machine). The amount of axial shortening was also reduced by using STORM.

Conclusion: Healing time is affected by translation at fracture site, which is a factor under the control of the surgeon. The second reduction method using STORM, helps achieve better reduction.

Introduction: The Staffordshire Orthopaedic Reduction Machine (STORM) was developed to assist in the reduction of tibial shaft fractures prior to the application of an external fixator. Its use has now been extended to fractures of the tibial plateau and plafond, where it has been utilised to gain and hold a good reduction prior to the application of various internal and external fixation techniques.

Methods: The STORM was used sterile within the operative field on a standard radiolucent operating table. It was applied with two tensioned 2 mm wires: the distal through the calcaneum; the proximal through the proximal tibia for shaft and pilon fractures, and through the distal femur for plateau fractures.

Controlled traction was applied through these two wires. Torsion was independently corrected and locked. Translation and angulation was corrected using two translation arms each applied to the tibia with a single unicortical screw. The STORM was removed at the end of each operation.

Results: The STORM was used in 241 cases.

Pilon (n=42): bridging hinge 23 (t [mean operation time in minutes]=102.9), percutaneous plate 10 (t=131.4), ring fixator 5 (t=140), screws and fibula plate 3 (t=77), other 2.

Discussion: The STORM is a safe device for reliable reduction of tibial plateau, shaft and pilon fractures which allows good access for internal or external fixation. No significant complications attributable to the use of the current design of the STORM were encountered.

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.

It is widely accepted that the use of radiographs to assess fracture healing is, at best, misleading. It is also known that physical manipulation of the fracture can also produce misleading results. The determination of a fracture healing using a quantifiable rather than a qualitative assessment process is desirable for two reasons. Clinically, it avoids the premature or delayed removal of the treatment regime. In research it is required to better distinguish between treatment methodologies in comparative studies. The aim of this paper is to present the need for such a measurement and describe alternative methods that have been adopted. Further, a new device is presented that enables users to measure the linear and non-linear properties of healing callus with a high degree of certainty.

An initial trial of 21 patients with unstable diaphyseal tibial fractures was conducted. The patients had their fractures reduced using the Staffordshire Orthopaedic Reduction Machine and subsequently treated with an external fixator. From six weeks post treatment the progress of healing was assessed using manipulation, radiographs, fracture stiffness and multi-planar material property assessment. Fracture healing was deemed to have been obtained when a fracture stiffness in two planes was greater than 15 Nm/degree.

The paper presents results that demonstrate that the assessment of fracture healing using traditional manipulation and radiographs is erroneous. It will also demonstrate that the measurement of fracture stiffness can also be erroneous if loading rate is ignored. It further shows that fracture stiffness must be measured in two planes. Initial results examining principal stiffnesses will also be shown, along with the measurement of material properties based on work rather that stiffness.

This is a clinically based study to assess the reliability of fracture stiffness as a measurement of clinical union and investigate other indicators which may aid the clinician to accurately determine when fracture fixation may be removed.

A fracture bending stiffness in the sagittal plane of 15Nm/deg. has been stated as a satisfactory endpoint at which an external fixator may be removed from diaphyseal fractures of the tibia. However using this as a measure to determine when to remove support in a study of 76 patients 4 continued to a malunion. Fracture callus properties were measured in clinic. The fixator was removed for the tests and a specially designed system was used to measure displacement and load. Fracture stiffness was measured in different planes and at various loading rates. Passive stressing of the leg was performed whilst fracture displacement was recorded. A constant load was applied for a longer period to assess creep properties.

Fracture stiffness was found to vary between different planes of measurement and on load rate. The visco-elastic characteristics of the callus changed with time. In early measurements, the callus absorbed a large proportion of energy when a load was applied. Later tests showed a progressive change with the callus absorbing less energy. This demonstrates that the properties of the callus changed with time, with the viscous element diminishing and the elastic element increasing. This sometimes occurred with no change in the measured fracture stiffness.

Further investigation is needed, focusing on the visco-elastic properties of callus, to develop a more reliable method of determining clinical union.

A study was undertaken of externally fixed tibial fractures in which a fracture stiffness of greater than 15Nm/° was used to define when the frame was removed were included 37 patients were studied; 20 (54%) non-smokers and 17 (46%) smokers. The two groups were comparable (ANOVA p=0. 35) for other factors.

Mean healing times in the non-smokers was 15. 5 weeks and in smokers was 21. 2 weeks (t-test p=0. 05).

We encourage all patients with tibial fractures to stop smoking by quoting an increase of treatment time of six weeks.