Hybrid external fixation: a viable option for complex trauma of the lower limb?

Complex lower extremity trauma is a challenging problem and requires a multidisciplinary approach. These injuries often result from high-energy trauma, compromising vital structures and causing major tissue loss.

When facing severe polytrauma, whether to salvage or amputate the affected limb is a common question. Despite conflicting data, there is a trend to favor lower limb retention as long as it is painless and retains function. Although this is not always possible, as in cases of anatomical complete disruption of the posterior tibial nerve in adults, there have been several advances in surgical techniques and devices that allow for better management of such intricate injuries. 

One innovation is the development of hybrid external fixators, which enable secure fixation of comminuted fractures near joints. With hybrid systems, tensioned wires are placed across the bone fragments and connected to a ring fixator, which is in turn attached to the bone shaft with pins and rods.

In this article, we will explore the use of hybrid external fixators to manage complex traumas in the lower extremities, providing some examples of such devices.

Principles of hybrid external fixation

As previously mentioned, the basis of hybrid external fixation involves a construct in which percutaneous wires are used to reduce displaced metaphyseal and articular fragments in conjunction with a ring fixator. The construct is stabilized through attachment to the bone shaft using pins.

The use of small tensioned wires in hybrid fixators has become an accepted treatment option in complex lower limb traumas, since they can avoid the soft tissue complications that can result from other types of fixation. Research by Watson and colleagues has shown that the stability of a four-wire construct is comparable to the gold standard of dual plating internal fixation techniques in complex fractures of the proximal tibia, thus showing the clinical relevance of hybrid external fixation.

The use of hybrid external fixation has been reported in high energy intra-articular fractures of the proximal tibia, which can be quite challenging to manage when associated with marked loss of soft tissue. In a retrospective analysis of 33 patients with bicondylar tibial plateau fractures, Babis and colleagues evaluated if minimal intervention and hybrid external fixation using the Orthofix system could provide a fair outcome with less complications when compared with other methods of internal and external fixation. Based on their results, the authors concluded that the Orthofix hybrid external fixator performed well. A total of 26 patients regained functional use of the knee joint, good axis, without pain or instability, with minor complications such as pin tract infections, stiffness or malunion occurring in 5 patients. One patient suffered a major complication, with septic nonunion and osteomyelitis, but no amputation was required.

The possibility of less impact to already damaged soft tissue is one of the advantages of using a hybrid external fixator.

Orthofix understands the need for effective, easily available solutions in the trauma setting and has developed three types of hybrid external fixators: the XCaliber®, the Galaxy™, and the Procallus®.

The XCaliber® Hybrid Fixator is made of radiolucent material, packaged in a sterile kit in three configurations ready for application in different long bones. Its radiolucent material allows for easier visualization in radiographs while requiring less radiation exposure for the surgical team.

The Galaxy™ Hybrid Fixator combines the advantages of tensioned wires and cortical screws, having a fast assembly and offering versatility due to a comprehensive external fixation system composed of the TL-HEX ring connected to Galaxy clamps and rods using dedicated Galaxy TL-HEX Connecting Posts.

The Procallus Hybrid System™ is made of TL-HEX ring connected to the Procallus fixator body using a dedicated clamp, providing good stability by combining the advantages of tensioned wires and cortical screws. It allows for free wire placement at multiple levels and angulations prior to ring connection, resulting in fracture stabilization without compromising the soft tissues.

The philosophy underlying the number of options for specific anatomical areas is to provide adequate stability and allow for early functional recovery, thus improving the patient’s quality of life.

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