Temporary circular external fixation for spanning the traumatised ankle joint: A cohort comparison study

Temporary spanning fixation aims to provide bony stability whilst allowing access and resuscitation of the traumatised soft-tissue envelope. Conventional monolateral fixators are prone to half-pin morbidity in feet, variation in construct stability and limited weight-bearing potential. This study compares traditional delta-frame monolateral external fixators to ankle spanning circular fixators.

Two cohorts were matched for demographics and fracture patterns. The quality of initial reduction and the maintenance of reduction until definitive surgery was assessed by two authors and categorised into four domains. Secondary measures included fixator costs, time to definitive surgery and complications.

Fifty-five delta-frames and 51 circular fixators were statistically matched for demographics and fracture pattern. "Excellent" and "Good" initial reduction was achieved in 50 (91%) delta-frames and 51 (100%) circular fixators (p = 0.027). Deterioration of initial reduction quality was seen in 12 (22%) delta-frames and two (4%) circular fixators (p < 0.001). Post-fixator dislocation occurred in five (9%) delta-frames and one (2%) circular fixator (p = 0.147). Median duration in spanned fixation was 11 days in both groups (p = 0.114). Three (5%) delta-frames and 13 (25%) circular fixators were used as definitive fixation. The mean implant cost was 4,307 USD for delta-frames and 3747 USD for circular fixators.

Temporary spanning circular fixation offers superior intra-operative reduction and maintenance of reduction and provides more opportunity to be used as definitive fixation. Circular fixation implants also proved to be less expensive and protected against further scheduled or unscheduled returns to theatre.

IV, retrospective cohort study.