Alignment in Total Knee Arthroplasty: Is a Neutral Mechanical Axis the Target?
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One long-held tenet of mechanically aligned (MA) total knee arthroplasty (TKA) is that implant durability is promoted by setting the alignments of the femoral and tibial components referenced to the mechanical axes of the femur and tibia in the coronal plane. Kinematic alignment (KA) is an alternative alignment paradigm that co-aligns the axes and joint lines of the components with the three ‘kinematic’ axes and joint lines of the pre-arthritic or native knee without placing limits on the pre-operative deformity and post-operative correction and without ligament release. In 2018, the technique of kinematic alignment received FDA approval and CE marking, enabling use throughout the world. KA is of interest because three meta-analyses, three randomized trials, and a national multicenter study showed that patients treated with KA reported significantly better pain relief, function, flexion, and a more normal-feeling knee than patients treated with mechanical alignment (MA). This symposium will feature speakers' opposing views, which will provide insight on the benefits, risks, and shortcomings of both the mechanical and kinematic targets.