Arthroscopic ankle arthrodesis is known to offer high fusion rates, improvements in pain and functional outcomes, low risks of complications, and reinterventions. The aim of this study is to compare open vs. arthroscopic ankle arthrodesis in patients at high risk of complications.A single-centre retrospective comparative analysis of ankle fusions was conducted. Patient records were screened for demographics, type of arthrodesis, follow-up length, pre-operative diagnosis, risk factors for non-union, operative time, radiographic union, time to union, complications, and reinterventions. The American Orthopedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Scale, the Italian version of the Foot Function Index (FFI), and a visual analog scale (VAS) for pain scores collected pre-operatively and in the last follow-up were used to assess clinical outcomes.There were 23 open and 21 arthroscopic ankle fusions. Union rate was higher (90.5% vs. 65.2%, p < 0.05) and complication rate was lower (14.3% vs. 47.8%, p < 0.05) in the arthroscopic group. In addition, patients who underwent arthroscopic arthrodesis reported better pain control, with higher improvements in VAS for pain scores. There was no significant difference in length of operative time, time to fusion, AOFAS, and FFI scores improvements between the two groups.Arthroscopic ankle arthrodesis resulted in higher union rates, fewer complications, and lower reoperation rates in patients at high risk of complications.