Pulmonary embolism following ankle fractures treated without an operation - an analysis using National Health Service data.

The majority of ankle fractures are stable and can be treated without an operation, most commonly with cast immobilisation. Based on concerns regarding the risk of a venous thromboembolic event (VTE) while immobilised, there is currently debate as to whether these patients should receive VTE prophylaxis for the duration of treatment. Rates of pulmonary embolism (PE) in this patient group are unknown. This retrospective cohort study was designed to identify patients treated without an operation for ankle fracture and determine the occurrence of PE and inpatient mortality within 90 days of injury using the English National Health Service administrative databases. Logistic regression models were used to assess the influence of age, gender and Charlson co-morbidity score on these outcomes. We identified 14777 adult patients over a 54-month period (April 2007-September 2011) that met our linkage and inclusion criteria (isolated, unilateral closed ankle fracture that did not require hospitalisation). Mean age was 46.4 years (range 18-99) and the majority had a Charlson 0 score (97.7%). There were 32 (0.22%) PEs within 90 days of the fracture (including in one patient who subsequently died). After adjustment, Charlson score of ≥1 was associated with a greater risk of PE (Odds ratio = 11.97, p < 0.001) compared to Charlson 0. Risk for these patients was 2.08%. In total, fifteen patients (0.11%) died in hospital within 90 days. Pulmonary embolism is rare following ankle fractures treated without an operation. Patients with multiple co-morbidities are at a higher risk. Based on this evidence, an ankle fracture treated without an operation does not appear to be an indication for routine VTE prophylaxis.