A comparison of intramedullary and extramedullary alignment systems for tibial component placement in total knee arthroplasty.

Fifty-two primary total knee arthroplasties (TKAs) using an intramedullary tibial jigging system to obtain ideal tibial alignment (90 degrees +/- 2 degrees) were compared with 62 TKAs using an extramedullary tibial jigging system. The Insall-Burstein total knee system was used in all cases, and all femoral components were positioned with extramedullary jigs. Postoperative evaluation consisted of a standing, hip-to-ankle anteroposterior roentgenogram and measurement of the following angles: (1) femorotibial, (2) tibial component, (3) femoral component, and (4) mechanical axis. Ideal tibial component alignment using the intramedullary system was statistically superior to alignment achieved with the extramedullary system. All other angle comparisons showed no statistical significance.