The selected design is a multi-center, non-randomized, prospective study of 200 subjects in the US with up to 13 investigational sites and a potential for more as needed to meet the enrollment requirements. The study subjects included are those with ankle joints damaged by severe rheumatoid arthritis, post-traumatic disease, and degenerative arthritis and implanted with the INFINITY™ With ADAPTIS™ Technology Total Ankle System.