Preoperative incongruent subtalar joint predicts less favorable clinical outcome in total ankle arthroplasty

This study aimed to determine the clinical effect of incongruent subtalar joint space on total ankle arthroplasty (TAA). Thirty-four consecutive patients who underwent TAA were grouped according to the status of subtalar joint incongruency. A comparison of clinical and radiographic parameters between groups as well as multiple regression analysis was performed to identify contributing factors to the final functional outcome. The final American Orthopaedic Foot and Ankle Society (AOFAS) score was significantly higher in the congruent group compared to that of the incongruent group (p = 0.007). There were no significant differences between the two groups in measured radiographic angles. In multiple regression analysis, the female sex (p = 0.006) and incongruency of the subtalar joint (p = 0.013) were found to be significant contributing factors to the final AOFAS score. A thorough preoperative investigation should be taken into the state of the subtalar joint for TAA.