Background. Total ankle arthroplasty is an accepted alternative to arthrodesis of the ankle. However, complication and failure rates remain high compared to knee and hip arthroplasty. Long-term results of the Scandinavian Total Ankle Replacement (STAR) are limited, with variable complication and failure rates observed. This prospective study presents the long-term survivorship and the postoperative complications of the STAR prosthesis. Additionally, clinical outcomes and radiographic appearance were evaluated. Methods. Between May 1999 and June 2008, 134 primary total ankle arthroplasties were performed using the STAR prosthesis in 124 patients. The survivorship, postoperative complications and reoperations were recorded, with a minimum follow-up period of 7.5 years. Clinical results were assessed using the Foot Function Index (FFI) and the Kofoed score. The presence of component migration, cysts and radiolucency surrounding the prosthesis components, heterotopic ossifications and progression of osteoarthritis in adjacent joints were determined. Results. The cumulative survival was 78% after a 10-year follow-up period (Figure 1). An ankle arthrodesis was performed in the 20 ankles that failed. Fourteen polyethylene insert fractures occurred. Other complications occurred in 29 ankles, requiring secondary procedures in 21 ankles. Nevertheless, the postoperative clinical results improved significantly. Osteolytic cysts were observed in 59 ankles and the surface area of these cysts increased during follow-up, without any association with the prosthesis alignment or clinical outcome. Heterotopic ossifications at the medial malleolus were present in 58 cases and at the posterior tibia in 73 cases, with no effect on clinical outcome. Osteoarthritis of the subtalar joint and talonavicular joint developed in 9 and 11 cases, respectively. Conclusion. The long-term clinical outcomes for the STAR were found to be satisfactory. These results are consistent with previous studies; however, the survival and complication rates are still disappointing compared to the results obtained in knee and hip arthroplasty. Higher rates of successful outcomes following ankle arthroplasty are required, and these results highlight the need for further research to clarify the origin and significance of the reported complications. Figure 1. Kaplan-Meier survivorship analysis with revision or removal of the tibia and/or the talus component for any reason as the endpoint, showing 78% (95% confidence interval 0.63–0.88) survival at 10.28 years follow-up. For figure, please contact authors directly

Background. Ankle arthroplasty is increasingly used to reduce pain and improve or maintain joint mobility in end-stage ankle arthritis. Both treatments show similar results with regard to functional outcome scores and sport related activities. However, the rates of complications and reoperations were higher after ankle replacement. Particularly for the first implant designs, with more promising results for newer designs. One of these newer designs is the Mobility Total Ankle System. Short term results in recent literature describe an improvement of functional outcomes; however complication rates vary widely, ranging from 9 to 37% and the 4-year survival rates ranging between 84 and 98 percent. Therefore, the aim of this study was to assess the clinical and radiographic short term results of the Mobility prosthesis. Methods. Between March 2008 and September 2013, 67 primary total ankle arthroplasties with the Mobility prosthesis were performed, in 64 patients, by one experienced foot and ankle surgeon. Complications, reoperations, failures and the survival rate were retrospectively examined. Patient reported outcomes were assessed with the use of the FFI score and visual analogue scale (VAS) for pain. Prosthesis alignment was measured on the first weightbearing radiographs of the ankle according to the procedure described by Rippstein et al.1 (Fig. 1). Results. The mean follow-up period was 40 months (range 12–78 months). There were two intraoperative and 13 postoperative complications, requiring seven reoperations. The reason for reoperation was painful impingement of the medial and/or lateral gutter (n=4), a deep infection (n=1), subsidence of the talus component (n=1) and a cyst located in the tibiofibular joint (n=1). Failure occurred in three of the 67 cases, with one early deep infection with a loose tibia component, one case of aseptic loosening and one case of chronic ankle pain without an assignable cause. A two-stage revision, ankle arthrodesis and amputation of the lower leg was performed, respectively. The mean cumulative survival after 61.4 months was 95% (CI 84–98) (Fig. 2). There was a significant decrease in the median FFI pain and disability score. The pain subscore decreased from 56.4 to 22.2 points and the disability score from 61.1 to 33.3 points. The mean VAS pain was 26.5 for the ankle region. The tibial components were placed in a mean of 1.5° varus relative to the mechanical axis of the tibia in the frontal plane. Malalignment (>5°) was observed in four cases with a mean of 6.0° varus. In the sagittal plane, a mean posterior slope of 1.6° relative to the mechanical axis of the tibia was measured, with one case of 7.5° of anterior slope. The talar component was centred too far posteriorly in five cases, which was considered as malalignment. Conclusion. Despite few intraoperative complications and satisfactory clinical and radiological outcome, the incidence of postoperative complications, reoperations and failure indicate the importance of further development and research in the field of ankle arthroplasty. To view tables/figures, please contact authors directly