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Introduction: Robotic technology in total knee arthroplasty has been proven to improve accuracy of component positioning, achieve alignment targets, and balance the knee objectively. However, the utility of robotics in correction of severe varus deformities of the knee has not been investigated in detail. The aim of this paper was to establish the utility and describe the technique of robotic-arm assisted total knee arthroplasty (RA-TKA) in achieving pre-balance in severe varus deformities of the knee., Materials and Methods: Among the existing Mako (Stryker, Kalamazoo, Michigan) RA-TKA workflows, pre-resection workflow is limited to knees which can be pre-balanced by component positioning according to functional alignment. Mid-resection workflow (distal femur/tibia first) is reserved for complex cases, whereby the extension gap is balanced first. In our experience, both workflows could not achieve pre-balance in severe varus deformities, necessitating the need to develop a novel technique. The ability of the robot to execute precise bone cuts allows for a provisional postero-medial femoral bone cut in flexion, giving access to remove large inaccessible posterior osteophytes and the tight posterior capsule, thus balancing the knee in extension. The flexion gap is subsequently matched to the extension gap by alterations in axial component positioning., Conclusion: This novel "enhanced mid-resection workflow" technique establishes the utility of the RA-TKA in balancing severe varus deformities of the knee. We also propose an algorithm which simplifies and helps surgeons choose between the three workflows to pre-balance knees irrespective of the severity of the varus deformity.

Introduction: The purpose of this study was to: 1) determine the incidence of revision total knee arthroplasty (TKA); 2) correlate the percent of glycated hemoglobin with incidence of revision; and 3) determine the cause of revision in diabetic patients stratified by a glycated hemoglobin level., Materials and Methods: We analyzed 424,107 patients from a national private payer database from 2007 to 2015 to determine who had diabetes and underwent TKA. We determined the incidence of revision TKA in the overall cohort and stratified it by glycated hemoglobin levels. Correlation analysis between the levels of glycated hemoglobin and the incidence of revision TKA was performed. We performed descriptive statistics of the underlying cause of revision TKA in both the overall and stratified cohorts., Results: There was a 3.2% incidence of revision in the overall cohort. When stratified by glycated hemoglobin levels, the cohort in the 6.6 to 7.0% category had the lowest incidence of revision (2.9%). The cohorts in the 8.6 to 9% glycated hemoglobin category had the highest revision rate (4.7%). There was a significantly positive correlation between rate of revision and ascending glycated hemoglobin levels, and a significantly negative correlation between descending glycated hemoglobin levels and revision incidence. The most common cause of revision was infection in the overall and stratified groups., Conclusion: Sub-optimal glycated hemoglobin levels in diabetic patients correlated with increased revision rates in those who underwent TKA. Management of diabetics should be optimized before undergoing TKA to minimize revision surgery risk.