An ankle replacement procedure consists of replacing the worn-out joint surfaces of the ankle with metal and plastic components that are shaped to allow continued movement of the ankle. There are several different types of ankle replacement available. Infinity ankle implants are already routinely used in NHS hospitals. The INFINITY™ with ADAPTIS™ and EVERLAST™ ankle replacement system is a development of the Infinity ankle implant, designed to attach to the bone better and to wear out more slowly.

The purpose of the UK ADAPTIS™ Study is to assess the performance and function of the newly introduced INFINITY™ with ADAPTIS™ and EVERLAST™ technology Total Ankle System for total ankle replacement (TAR) or arthroplasty (TAA) and EVERLAST™ Poly Insert that modernises and streamlines Stryker's TAA/TAR portfolio.

UK ADAPTIS is a prospective multi-centre cohort series of INFINITY™ with ADAPTIS™ and EVERLAST™ Technology with Poly Insert for patients requiring primary total ankle replacement (TAR) i.e. Total Ankle Arthroplasty (TAA).

Patients meeting the criteria for the study will be asked to enrol by providing written informed consent.

The patients will be monitored clinically by post-operative follow-up examinations and Patient reported outcome measures (PROMs) (Manchester Oxford Foot & Ankle Questionnaire (MOXFQ), Ankle Osteoarthritis Scale (AOS), EQ5D-5L).

Intended use:

It is intended to give a patient limited mobility by reducing pain, restoring alignment, and replacing flexion and extension movement in the ankle joint.

Indications for use:

• Patients with ankle joints damaged by severe rheumatoid, post-traumatic, or degenerative arthritis.
• Patients with a failed previous ankle surgery.

Inclusion Criteria:

1. Male or non-pregnant female over the age of 21 years with a diagnosis of end stage ankle arthritis and requiring primary TAA/TAR and is suitable for the use of the ADAPTIS TAA/TAR
2. Patients who are physically and mentally willing and able to comply with the post-operative follow-ups and an appropriate rehabilitation schedule.
3. Patient can understand and provide written consent.

Exclusion Criteria:

1. Patients with previous ankle arthrodesis or Patients who require revision of previously implanted TAA/TAR.
2. Any patients presenting with clinically relevant conditions prior to implantation, that would contraindicate implantation of a TAA/TAR

It is anticipated that a publication of the anonymous study results will be compiled and submitted to a peer-reviewed journal. The CI of the study will have the responsibility of being primary author of such publications.

The study will be registered in the ISRCTN Trial Register and/or in clinicaltrials.gov by the CI.