A previous trauma is the most common origin of ankle osteoarthritis. Patients with post-traumatic osteoarthritis are generally younger. Due to the previous trauma and surgical treatment, the surrounding soft tissues are often scarred and inelastic. Structural changes of the osteoarthritic ankle are often significant, including deformity and instability, thus making the replacement surgery highly complex. Careful clinical examination and thorough radiographic assessment are mandatory to anticipate potential problems during TAR surgery and complications.