Introduction: Subtalar arthrodesis is a surgical procedure aimed at fusing the subtalar joint. One of the most common com plications of this procedure is non-union. This article aims to analyze the study and management of non-union in general, as well as its specific approach in the context of subtalar arthrodesis. Given that this is a common complication, it is crucial to enhance knowledge on this topic. Case Report: 42-year-old healthy male patient with a background of post-traumatic osteoarthritis of the left ankle, initially treated with tibiotalar arthrodesis in 2022 with subsequent revisions due to poor outcomes, presenting osteoarthritis of the subtalar joint that required management with a subtalar arthrodesis. The latter evolved with symptomatic non-union and it was decided to perform a revision subtalar arthrodesis in July 2024. Result: The patient showed a favourable postoperative clinical evolution, with adequate alignment and position of the osteosynthesis elements, with no signs of infection. At the last check-up (one month postoperatively), protected loading with an orthopaedic boot was started, showing a good recovery. Conclusions: Non-unions in joint fusions, particularly in subtalar arthrodesis, represent a significant challenge in traumatology, with high complication rates. Evaluation of non-unions should include a thorough clinical examination, laboratory testing and imaging techniques. Identification of risk factors, both systemic and local, along with proper surgical planning, are essential in preventing complications. Treatment strategies should address the underlying causes; surgical options and their success should have a multidi mensional approach that addresses both technical and biological aspects of the procedure. Finally, the implementation of well-structured diagnostic and therapeutic algorithms is crucial to improve functional outcomes and ensure successful bone fusion.