Abstract
Introduction
Ankle replacement is now common in the UK.
In a tertiary referral NHS practice, between 1997–2011 we implanted two types of cementless mobile bearing total ankle replacements (TAR).
Methods
We reviewed our operative database and electronic patient records and confirmed the number of prosthesis with our theatre records. All case notes and radiographs were reviewed. Failure was taken as revision, and patients were censored due to death or loss to follow-up. The survivorship was calculated using a life table (the Kaplan-Meier method), with 95% confidence intervals.
Results
We found a total of 358 NHS patients had a TAR from Jan 1997 to April 2012 total ankle replacements; the mean follow up was 76 months. The principle indications for surgery included primary OA (n=146) and inflammatory arthritis in (n=79). Overall survival was 90.9% (94–84) at 10 years.
A complication requiring revision developed in 42 ankles and 36 were revised or fused. Thirty-two TAR's underwent further hind foot fusions which were not attributed as a failure of the prosthesis. We arthroscoped 6 TAR's for hetrotrophic calcification.
When we separated the implants we found the STAR (implanted from 1997–2004) had a 5-year survival of 95.2% (98–91) and the Mobility (implanted from 2004–11) of 92.6% (96–88). We found early failures (within 2 years of implantation) were higher within 2 years of introduction of TAR and on changing our prosthesis.
Conclusion
In a study of TAR undertaken at one centre principally by an experienced surgeon and team, we have shown a learning curve.
Cementless mobile bearing total ankle replacements (TAR) conducted on a routine basis with careful patient selection has a 90.9% survivorship over a 10-year period. The difference in survival for two implants is not statistically significant.
