SLR - July 2015 - Joseph Baker

Intermediate to Long-Term Outcomes of Total Ankle Replacement with the Scandanavian Total Ankle Replacement (STAR)

Reference:  Daniels T, Mayich DJ, Penner M.  Intermediate to Long-Term Outcomes of Total Ankle Replacement with the Scandanavian Total Ankle Replacement (STAR).  Journal of Bone and Joint Surgery.  2015 June; 97(11): 895-903.

Scientific Literature Review

Reviewed By:  Joseph Baker, DPM
Residency Program:  Detroit Medical Center

Podiatric Relevance: The use of total ankle implants has increased in recent years, owing to improved implant design and technique.  Studies evaluating outcomes of these procedures is important in determining their clinical use.  The authors report intermediate- and long-term outcomes using the STAR implant at two Canadian centers.

Methods: A prospective study was carried out at two urban, teaching hospitals.  All consecutive patients who underwent total ankle arthroplasty with the STAR implant were included.  All patients underwent a procedure with the use of a cementless, mobile-bearing, three-component implant.  Additional procedures required intra-operatively were recorded.  Data included preoperatively included demographics, diagnoses, and comorbidities.  Patients were evaluated in clinic post-operatively. 

Outcomes were assessed with the Ankle Osteoarthritis Scale (AOS) and Short Form-36 SF-36).  Revision ankle arthroplasty was defined as the need to remove one or more metal components, or amputation.  Postoperative complications and the incidence of polyethylene exchange were also recorded. 

Results: There were one-hundred and eleven ankle that underwent total ankle arthroplasty with the STAR implant in this study.  The mean age was 61.9 ± 11.9 years; half of the patients were male.  Sixty-eight of the ankles required 121 additional procedures intra-operatively, including gastrocnemius release, subtalar arthrodesis, triple arthrodesis, Achilles tendon lengthening, and hardware removal. 

There was a mean duration of follow-up for all living patients without revision (seventy-three ankles) of 9.0 ± 1.0 years.  Metal component revision was required in thirteen (12%) of the ankles at a mean of 4.3 ± 3.0 years.  Polyethylene component exchange was recorded in twenty of the ankles (18%) at a mean of 5.2 ± 2.1 years.  The patient-reported outcomes showed a mean change of -36.5 ± 23.3 points for AOS pain, -38.6 ± 26.8 points for AOS disability, and 9.6 ± 10.3 points for the SF-36 component summary score.  The SF-36 mental component summary score did not change from pre-operative measurements. 

Conclusions: The authors showed that patient-reported outcomes for total ankle arthroplasty using the STAR implant were good, and that long-term outcomes had a 12% rate of metal component revision and 18% rate of polyethylene failure.  The revision rate was found to be higher in the first twenty ankle implants performed by the authors, however, they do point out that these patients had an additional two years of follow-up, which may influence the outcome.  The conclusions reached by the authors are similar to previous reports, which adds to the growing amount of literature on total ankle arthroplasty using the STAR implant.

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