Temporary external fixators spanning the traumatised ankle joint has remained relatively unchanged since Sirkin et al. introduced the concept of “span-scan-plan” in 1999 [1]. This approach has subsequently been shown to be superior to splint immobilisation for both ankle and distal tibia fractures whilst awaiting definitive management [2,3].

Numerous constructs have been proposed to optimally immobilise the ankle joint whilst allowing elevation of the limb and access to the ankle for soft-tissue care [4], [5], [6], [7], [8], [9], [10]. Spanning constructs are generally based on implant availability and surgeon choice garnered through training or experience. These constructs may be subtly adjusted to accommodate bony and soft-tissue injuries, allowing flexibility to deal with individual case variation, avoid fixation in the zone of injury, and optimise access for soft-tissue reconstruction procedures [11]. To be effective, the chosen external fixator must provide 3-dimensional stability around the ankle without temporal deterioration of stability. In rare instances, patients may not be suitable for definitive fixation and might be definitively treated in a spanning fixator; therefore, the spanning construct will need to maintain its function for extended periods.

Monolateral “bar-and-clamp” spanning external fixators rely on half-pin fixation that may induce bone lysis pin site infections and prevent weight bearing when used in the foot. Calcaneal half-pins are particularly uncomfortable and can lead to adjacent lysis, instability, and potential loss of initial reduction due to the cancellous bone quality. Every effort must be made to provide the requisite stability until definitive fixation, which can vary significantly depending on associated soft-tissue and other concomitant injuries. As such, situations could arise where these external fixators are either mechanically suboptimal or over-engineered with excessive use of expensive components.

The proposed alternative is a spanning circular external fixator which does not require extensive Ilizarov frame expertise. The TrueLok (Orthofix, Italy) system provides unique features that allow a spanning circular fixator to be constructed and applied without expensive hexapod struts. The theoretical advantage of such a fixator is the circumferential, 3-dimensional stability it can provide.

This study aims to compare the quality of initial reduction and maintenance of reduction between a traditional bar-clamp monolateral external fixator (delta-frame) against a TrueLok (Orthofix) Trauma circular external fixator (CEF). Secondary objectives were a cost analysis between devices and assessing unplanned returns to the operating theatre.