Improving Tibial Component Coronal Alignment During Total Knee Arthroplasty with Use of a Tibial Planing Device

Background: The outcomes of knee arthroplasty have been shown to be affected by component alignment. Intramedullary and extramedullary alignment instrumentation are fairly effective for achieving the desired mean tibial component coronal alignment. However, there are outliers representing >3° of varus or valgus alignment with respect to the anatomic tibial shaft axis. We measured the efficacy of a custom tibial planing device for reducing the outliers in tibial alignment. Methods: We designed a tibial planing tool in an effort to improve tibial alignment. In one cohort (100 knees), we used traditional intramedullary alignment instrumentation to make the tibial bone cut. In a second cohort (120 knees), we used intramedullary alignment instrumentation to make the cut and also used a custom tool to check the cut and to correct an inexact cut. Tibial tray alignment relative to the long axis of the tibial shaft was measured in the coronal and sagittal planes on postoperative radiographs. The target coronal alignment was 90° with respect to the tibial shaft axis (with