Incidence of Nonunion After Isolated Arthroscopic Ankle Arthrodesis

Purpose: To determine the incidence of nonunion after isolated arthroscopic ankle arthrodesis. Methods: Electronic databases and relevant peer-reviewed sources, including OvidSP/Medline (http://ovidsp.tx.ovid.com) and Google, were systematically searched for the terms "arthroscopic ankle arthrodesis" AND "nonunion". Additionally, we manually searched common American, British, and European orthopaedic and podiatric scientific literature for relevant articles. Studies were eligible for inclusion only if they included the following: isolated ankle arthrodesis, greater than 20 ankles, minimum mean follow-up of 12-months, a 2-portal anterior arthroscopic approach, fixation with 2 or 3 large-diameter cannulated cancellous screws, and the nonunion rate with no restriction on cause. Results: After considering all the potentially eligible articles, 7 (25.9%) met the inclusion criteria. A total of 244 patients (244 ankles) -148 (60.7%) male and 96 (39.3%) female patients, with a weighted mean age of 49.2 years-were included. For those studies that specified the exact follow-up, the weighted mean was 24.1 months. A total of 21 nonunions (8.6%) were reported, with 14 (66.7%) being symptomatic and requiring further intervention. Conclusions: The results of this systematic review reveal an acceptable incidence of nonunion of 8.6%. However it is important to recognize that of these nonunions, 66.7% were symptomatic. This supports the belief that regardless of approach, nonunion of an ankle arthrodesis is problematic. In light of this finding, additional prospective studies are warranted to compare directly the incidence of nonunion between open, minimum incision, and arthroscopic approaches with a variety of fixation constructs. Level of Evidence: Level IV, systematic review of level IV studies.