Post- Approval Hintermann Series H® Study 1

Inclusion Criteria: * Skeletally mature * Primary diagnosis of osteoarthritis, post-traumatic arthritis or rheumatoid arthritis * Primary total ankle replacement * Unilateral or the first ankle implanted if bilateral and the surgery dates for both sides are at least 6 months apart * Implanted with the correct device without screws (for investigational arm), * 3rd generation Hintermann Series H3 Total Ankle Replacement; * Poor pre-operative American Orthopaedic Foot and Ankle Society Hindfoot Score (\< 60 points) * Implanted in 2013 or earlier). Note that all subjects implanted in 2013 or earlier were included regardless of whether they were revised prior to the 2 year endpoint. * Gave informed consent (unless IRB/Ethics Committee waived this requirement) Exclusion Criteria: * Prior TAR or arthrodesis at the involved ankle joint