The INBONE-2 Total Ankle Prosthesis: Outcomes At 5 to 9 Years Follow-Up

CATEGORY: Ankle; Hindfoot; Other INTRODUCTION/PURPOSE: Short and medium term outcomes of the INBONE I and INBONE II tibial stems have been favorable. The INBONE-2 talus has been shown to have lower reoperation and failure rates compared to its predecessor, INBONE-1 at short term follow-up. The purpose of the present study was to assess mid-term outcomes for the INBONE-2 prosthesis at 5 to 9 years follow-up considering both the tibial and talar components. METHODS: All patients who underwent primary total ankle arthroplasty (TAA) with INBONE-2 between July 2010 and July 2014 at a single institution and who were at least 5 years postoperative were included. A total of 15 ankles with a mean follow up 85 (range, 61-113) months met the criteria. Radiographs were assessed using coronal and sagittal alignment parameters preoperatively, at 6 weeks postoperative, and at the most recent follow-up. Medical records were reviewed and revisions, reoperations, and complications were classified according to the criteria established by Vander Griend et al. and Glazebrook at el., respectively. RESULTS: Survivorship for the INBONE-2 at a mean of 85 months was 93.7%. Coronal and sagittal tibiotalar alignment improved after surgery (p=0.081, p=0.15), and was maintained at the most recent follow-up (p=0.684, p=0.837). One ankle (6.7%) required early component revision; while 4 (26.7%) required a non-implant related revision. Six complications (2 high grade, 1 intermediate, and 3 low) in 5 ankles (33.3%) were recorded according to the Glazebrook classification system. CONCLUSION: The present study is the first to report midterm follow-up after TAA with the INBONE-2. High survivorship, maintenance of correction, and a low incidence of major complications was observed. The most common complication overall was lateral gutter impingement, which accounted for the majority of the non-revisional reoperations.