Correction of Talar Sagittal Alignment Using a Novel Biased Polyethylene Insert for a Fixed Bearing Total Ankle Arthroplasty

Category: Ankle Arthritis; Ankle Introduction/Purpose: The Cadence Total Ankle System is unique in that it has modular polyethylene components with both an anterior and posterior biased option that may improve reduction of the talus in the sagittal plane. As such, the purpose of this study is to evaluate the effectiveness of anterior and posterior biased polyethylene liners in improving sagittal component alignment and functional outcomes after TAA. Methods: This was a retrospective cohort study of consecutive patients that underwent TAA with the Cadence Total Ankle system using biased polyethylene liners with at least 12 months follow-up. Results: Study included 66 TAAs that required the use of a biased polyethylene liner. The primary outcome was radiographic sagittal talar alignment, the cohort was broken down into three groups depending on preoperative sagittal alignment: anterior alignment (A, n=38), neutral alignment (N, n=17), and posterior alignment (P, n=11). Patients with anterior or posterior preoperative sagittal alignment demonstrated significant improvement in sagittal alignment using both the TT ratio and talar station. Overall, the proportion of patients that achieved neutral sagittal balance significantly improved from 25.76% to 50.00% postoperatively (χ2 [df=1, n=66] = 18.24, p < 0 .01). Anterior bias liners were associated with anterior preoperative alignment, while posterior bias liners were associated with neutral and posterior preoperative alignment (χ2 [df=2, n=66] = 17.55, p < 0 .01, V = 0.52). Conclusion: The Cadence TAA system has novel anterior and posterior biased polyethylene liners that may augment correction of sagittal talar deformities. This study demonstrates that biased liners are effective in correction of pathological sagittal talar deformities to near anatomic alignment clinical with significant improvement in functional outcomes.