The AO triangular external fixator: a backup option in the treatment of ankle fractures in geriatric patients?

PURPOSE To analyze the indications, radiological short-term outcomes, and complications of ankle fractures in geriatric patients treated with a triangular external fixator (AEF) until fracture healing. Furthermore, the effect of an additional osteosynthesis to AEF on the radiological outcome was investigated. METHODS Retrospective analysis of ankle fractures treated in a Level I Trauma Center between 2005 and 2015 with an AEF in patients aged ≥ 65 years until fracture has healed. The combination of AEF and at least one additional osteosynthesis of a malleolus was defined as hybrid external fixator (HEF). At the time of AEF removal, a preserved ankle joint congruity was defined as good radiological outcome. Incongruity more than 2 mm was defined as poor radiologic results. RESULTS 16 patients (13 women, 3 men) with a mean age of 74 years (SD 6.2) were treated with AEF until fracture healing, 9 with a single AEF and 7 with a HEF. Stabilization with HEF (n = 7 [100%]) showed higher rates of good radiological outcome than AEF alone (n = 4 [44%] of 9; p = 0.034). The duration of therapy did not differ between HEF and AEF (70 day vs 77 days). 4 patients (22%) required surgical revision. CONCLUSION It could be shown that osteosynthesis in addition to AEF leads to a better radiological short-term results than using AEF alone. Therefore, in the situation where an AEF is considered as the definitive treatment option for an ankle fracture in geriatric patients with expected or existing soft tissue problems, it should be done or completed as a HEF. LEVEL OF EVIDENCE Therapeutic level IV.