The Scottish Arthroplasty Project: outcomes of 601 total ankle replacements over a 20 year period

Z. Higgs, C.S. Osam, C. Watling, P.J. Jenkins, C.S. Kumar

Introduction: Total ankle replacement (TAR) is performed for post-traumatic arthritis, inflammatory arthropathy, osteoarthritis and a range of other indications. The Scottish Arthroplasty Project (SAP) began collection of data on TAR in 1997. In this study, using data from the SAP, we examined the annual incidence of TAR between 1997 and 2015. Implant survivorship and the rate of general and joint-specific complications were also analysed.

Methods: We identified 601 patients from a national arthroplasty database who had undergone total ankle replacement between 1997 and 2015 and followed up these patients to a maximum of 20 years. We used established methods of linkage with national hospital episode statistics, population and mortality data to examine the incidence of complications and implant survivorship.

Results: There were 601 primary TAR procedures with an overall incidence of 0.6 per 10⁵ population per year. Indications for ankle replacement included: posttraumatic arthritis/osteoarthritis 63%; inflammatory arthropathy 25% and other diagnoses including: haemophilia; haemochromatosis; psoriatic arthritis and avascular necrosis in 12%. The peak incidence was in the 6th decade. There was a female to male ratio of 1:1. The incidence of TAR increased over the study period (r= 0.9, p=< 0.0001). This may be due to a broadening range of indications and patient selection criteria, in turn due to increased surgeon experience with ankle replacement and the evolution of implant design. The overall 10 year survivorship was 90%. The rate of general and implant specific complications was comparable to published literature.

Conclusion: This study examines a large number of ankle replacements from an established arthroplasty dataset. The prevalence of TAR has increased over 19 years. Overall survivorship was similar to other published registry data on ankle replacements. Further work will look at the effect of surgeon volume on rate of complications, reoperation and survivorship.