Clinical alignment variations in total knee arthroplasty with different navigation methods

BackgroundWe compared the resulting alignment in 90° of flexion and in full extension after total knee arthroplasty (TKA) with two navigation systems using different techniques: a measured resection (MR) system and a gap — balancing (GB) system.MethodsVarus and valgus alignment in extension and flexion was compared in 100 consecutive patients who had TKA with an MR distal–femoral-cut-first technique at one institution and 100 consecutive patients in whom a GB tibial-cut-first technique was used at another institution. Alignment deviation of three degrees or more from neutral was considered an outlier.ResultsNo significant difference between the groups in coronal alignment in extension or flexion was found, but there were three times the number of outliers for clinical alignment in flexion for the MR group compared to the GB group.ConclusionsThe use of the GB tibial-cut-first computer-assisted TKA navigation may provide a more consistent clinical alignment in flexion than systems using an MR technique.Level of evidenceTherapeutic study. Level 2.