SLR - October 2017 - Sham J. Persaud

Survival of the Scandinavian Total Ankle Replacement (STAR): Results of 10 to 19 Years Follow-Up

Reference: Frigg A, Germann U, Huber M, Horisberger M. Survival of the Scandinavian Total Ankle Replacement (STAR): Results of 10 to 19 Years Follow-Up. Int Orthop. 2017 Jul 26.

Scientific Literature Review

Reviewed By: Sham J. Persaud, DPM
Residency Program: The Western Pennsylvania Hospital, Pittsburgh, PA

Podiatric Relevance: The use of total ankle replacements for the treatment of end-stage ankle arthritis is becoming more popular among foot and ankle surgeons. End-stage ankle arthritis is a debilitating condition with substantial impact on activity level and quality of life. Surgical management of this debilitating disorder includes arthrodiastasis, arthroscopy, arthrodesis or joint replacement. In the literature presented, 10-year survival rates for TAR range from 62 percent to 95 percent. The purpose of this study was to evaluate the STAR total ankle replacement survival and clinical success after a minimum of 10 years follow-up.

Methods: Forty-six patients, including 50 ankles with end-stage ankle osteoarthritis, underwent STAR prostheses operations by a single surgeon between 1996 and 2006. For the patients to be included within the study, a minimum follow-up of 10 years was required. Kofoed clinical scores and radiological assessments were taken before the operation and at one, 10 and 16 years. The authors looked at three primary end points to determine survival. End points were defined as exchange of the whole prosthesis or conversion to arthrodesis (def. 1), exchange of at least one metallic component (def. 2), or exchange of any component including the inlay (def. 3). Survival was estimated according to Kaplan-Meier statistical analysis.

Results: The results of the overall survival rates of the prosthesis were determined at both 10 and 19 years. The 10-year survival rate was (def. 1) 94 percent (CI 82–98 percent), (def. 2) 90 percent (CI, 77–96 percent) and (def. 3) 78 percent (CI 64–87 percent). The 19-year survival rate was (def. 1) 91 percent (CI 78–97 percent), (def. 2) 75 percent (CI 53–88 percent) and (def. 3) 55 percent (CI 34–71 percent). Considering any reoperations related to STAR, 52 percent (26/50) of prostheses were affected by reoperations. Mean preoperative Kofoed score was 49, which improved to 84 after one year (n = 50), to 90 after 10 years (n = 46) and to 89 after 16 years (n = 28).

Conclusions: Although the article shows a 52 percent need for some form of revision surgery with STAR implants after 10 years, the study shows the majority of these patients were able to keep their implants with minor revision surgery with component or poly exchange. Ten-year and 19-year total removal of the implant only occurred in six and nine percent respectively. Therefore, it can be said that the survival rate of the STAR implant is quite impressive compared with other literature present. Nevertheless, we should always try to improve the surgical technique and technology of total ankle replacements. 

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