SLR - November 2012 - John Mostafa
Reference: Dhawan R, Turner J, Sharma V, Nayak R. Tri-Component, Mobile Bearing, Total Ankle Replacement: Mid-term Functional Outcome and Survival, The Journal of Foot & Ankle Surgery. 51: 566-69, 2012
Scientific Literature Review
Reviewed by: John Mostafa, DPM
Residency Program: Mount Auburn Hospital, Harvard Medical School, Cambridge, MA
Podiatric Relevance:
Due to the high failure rates and unsuccessful functional outcomes of highly constrained cemented first generation ankle implants, a shift has been implicated to an uncemented two or three component second generation system. Few long term follow-up studies have been illustrated to show the success rate and functional outcomes of these second generation implants, with the longest follow-up being 10 years. This study illustrates a 13 year follow-up for a tri-component total ankle implant.
Methods:
This was a retrospective study conducted between 1996 and 2009 that consisted of 29 patients for a total of 30 total ankle replacements that were followed for up to 13 years. The tri-component Buechal-Pappas total ankle replacement system was used in this study. Radiographic outcomes were measured by noting alignment, radiolucency, and migration of components using IMPAX software. The functional outcomes were measured using the AOFAS ankle and hindfoot score at a one-year follow-up period. If any of the tibial or talar components required revisions for any reason or if the patients went on to an arthrodesis due to chronic significant pain, this would be considered a failure.
Results:
Only three of the 30 implants required reoperation and these revisions were due to malplacement of the talar component. All failures were noted in the male patients. There were only three complications that were considered failures and one of the three went on to an ankle arthrodesis. Radiolucent lines were noted on three ankles (10 percent) and a medial malleolar fracture seen on two ankles (6.7 percent), but were not considered failures by the authors. The mean AOFAS ankle and hindfoot score after one year was 81. The mean survival of the implant was 10 years with age being a significant factor.
Conclusions:
This was the longest follow-up study known to our knowledge describing the success rates and functional outcomes of a tri-component total ankle implant system. The limitations to the study included small number of patients, use of a non-validated instrument (AOFAS ankle and hindfoot score) and the fact that the AOFAS score was not reported preoperatively so a change in AOFAS score could be determined. Further long term studies are needed to support the success of tri-component ankle implants.