Two consecutive series of patients who had cementless, porous-coated, congruent-contact, mobile-bearing total ankle replacements were evaluated during a 20-year interval using the New Jersey Orthopaedic Hospital ankle scoring scale to determine clinical outcome and overall implant survivorship with revision as an end point. The initial series of 38 patients (40 ankle replacements) using a shallow-sulcus design had diagnoses of: osteoarthritis, seven (17.5%); rheumatoid arthritis, nine (22.5%); posttraumatic arthritis, 21 (52.5%); and failed fusion, three (7.5%). Clinical results after 2–20 years, (mean, 12 years) were 28 (70%) good to excellent, two (5%) fair, and 10 (25%) poor. Postoperative ankle motion ranged from 10°–47° total arc (mean, 25° total arc). The 20-year overall survivorship for the shallow-sulcus design was 74.2%. A second series of 74 patients (75 ankle replacements) using a deep-sulcus design had diagnoses of: osteoarthritis, eight (11%); rheumatoid arthritis, nine (12%); osteonecrosis, three (4%); and posttraumatic arthritis, 55 (73%). Clinical results after 2–12 years, (mean 5 years) were 66 (88%) good to excellent, four (5%) fair, and five (7%) poor. Postoperative ankle motion ranged from 10°–50° total arc (mean, 29° total arc). The 12-year overall survivorship for the deep-sulcus design was 92%.