Ian Moorcroft
Technical Director
Intelligent Orthopaedics Ltd.
Stoke on Trent
UK
T: +44 (0) 1782 847 840
W: www.intelligentorthopaedics.co.uk
During the 1990s teams from the universities of Keele and Staffordshire, and the University Hospital of North Staffordshire, UK, were conducting research into the healing of long bone fractures, particularly fractured tibia. As part of one particular comparative clinical study it was necessary to precisely reduce tibial fractures in order to minimise the variable factors that could impact on healing times and eventual outcomes. The device that was originally made for this purpose was intended for the study only. However, all the surgeons that used the device found it to be so beneficial that they wanted to continue to use it after the study had concluded. It became apparent that the device, Staffordshire Orthopaedic Reduction Machine (STORM), would be a valuable surgical device in its own right.
Treating displaced or unstable fractures
STORM is used in the treatment of displaced or unstable fractures (Figure 1) where the patient will need a general anaesthetic and an operation. During the operation the surgeon will realign the fracture fragments, which is known as reduction. Obtaining an acceptable fracture reduction by other methods can be extremely difficult and time consuming as it requires considerable force to manipulate the fragments back into their correct alignment. In some circumstances the surgeon may need to open the fracture in order to achieve an acceptable reduction. The complexity of this process often results in the surgeon making a compromise between the quality of reduction and the time taken to achieve it. Once the fracture has been reduced the surgeon will then need to apply some kind of fixation to provide support to the fracture limb while it heals.
[[HHE06_fig1_T48]]
The type of fixation is dependent on a number of things including the type and location of the fracture, the facilities available at the point of treatment and the preferences of the surgeon and/or patient. In most methods the process of reducing the fracture is built into the operative technique and/or the design of the device, whether that be an intramedullary nail, screws and plate or external fixation system. In this way the fixation device must perform two distinctly different functions. First, it must allow the surgeon to manipulate the fragments to achieve a reduction. Second, it must support the fracture until it has united. The first function occurs in the sterile environment of the operating theatre and is for a short period only, while the second may last many weeks or months as the patient mobilises on the injured limb. These two opposing functions mean that the process of reducing the fracture is not optimised and current devices can be over complicated. Therefore, there is a need to make the process of fracture reduction easier to manage.
To perform the operative technique tensioned wires are inserted through the calcaneum and proximal tibia, and are held by a robust frame with independently controlled movements. Crucial to STORM’s function is the ability to apply uniform and sustained traction while allowing easy correction of rotation about the long axis of the bone. With traction applied and rotation corrected, unicortical bone screws are inserted into the proximal and distal fragments near to the fracture site and held in special attachments to the device. The bone screws can then be independently and accurately moved in both the sagittal and coronal planes. This enables precise alignment of the fracture ends. Once reduction is achieved, STORM firmly holds the bone fragments in place while the chosen method of fixation (internal or external) is applied. Figure 2 illustrates the STORM configuration.
[[HHE06_fig2_T49]]
Benefits
STORM, which has been used in over 300 operations on many types of lower limb fractures, aids the surgeon during fracture reduction by providing a controlled procedure, which lessens the unpredictability associated with lower leg fractures and, in most cases, results in perfect anatomical reductions. STORM also allows a progressive controlled technique to achieve the necessary distraction and then to correct rotation, angulation and translation.
The ability to accurately reduce the fracture before applying the fixation allows the surgeon to simply change the preferred fixation method during the operation to better suit the individual patient. Another proven benefit is that STORM helps in the planning of trauma cases where every case is different and can often present unexpected problems.
Patient and healthcare providers also benefit. Patients benefit from a shorter time under general anaesthetic and improved functional and aesthetic outcome. Healthcare providers benefit from shorter and more predictable operation times, which have direct cost savings, and allows for improved scheduling of operating lists.
STORM is used in conjunction with all main methods of fixation including; external fixators, minimally invasive plating systems, intramedullary nails, ring/frame and hybrid systems. In trials carried out in the University Hospital of North Staffordshire, the use of STORM with an external fixator was shown to shorten operating times by an average of 23% (p<0.02) and shorten the time to reduce the fracture by 53% (p<0.001). The accuracy of reduction using the STORM is significantly improved compared with conventional methods (p<0.01).
In the case of external fixation, the STORM method eliminates the need for complicated joint mechanisms in the fixator itself. Following the success of STORM the research team formed a spinout company, Intelligent Orthopaedics Ltd, which has since developed other product ideas. One of these, a simple external fixator, is designed for use in conjunction with the STORM. Figure 3 shows how this fixator can be easily applied with all pins in alignment while the STORM holds the bone fragments securely.
[[HHE06_fig3_T49]]
Finally, the emergence of Minimally Invasive Plating systems has presented new challenges including how to reduce the fracture without an open reduction technique. STORM helps in these cases by providing control of the bone fragments with minimal soft tissue damage (Figure 4).
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Conclusion
The STORM technique provides benefits to the patient, surgeon and healthcare provider. Patients benefit from a shorter time under general anaesthetic and improved fracture fragment proximity, which reduces the likelihood of complications during fracture healing. Evidence also suggests that shorter healing times and fewer long-term problems are associated with improved reduction.
Feedback from surgeons indicates that it gives greater control with more predictability when used with all common forms of fixation of unstable fractures from the tibial plafond to distal femur. Finally, healthcare providers can on average expect shorter and more predictable operating times enabling better scheduling of operating lists with improved direct and indirect costs.
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Reference
- Moorcroft CI,Ogrodnik PJ, Thomas PB, Verborg SA. A device for improved reduction of tibial fractures treated with external fixation. Proc Inst Mech Eng Part H 2000;214:449-57.
