Coronal and Sagittal Balancing of Total Knee Arthroplasty Old Principles and New Technologies.

The number of total knee arthroplasties performed in the United States is growing, and a leading cause of failure is postoperative knee instability from suboptimal coronal or sagittal balancing. This article reviews native knee anatomy as well as several guiding principles of total knee arthroplasty such as limb axis, femoral referencing, and implant constraint. Next, techniques that can be used by the surgeon to achieve ideal sagittal balance and coronal balance are discussed in detail. Finally, due to the growing use of computer and robotic technologies in knee replacement, the impact of advanced technologies on total knee arthroplasty balancing and alignment is reviewed. An in-depth understanding of these topics will enable surgeons to optimize the outcome of their total knee arthroplasty patients.