Varus/valgus alignment of the tibial component in total knee arthroplasty

The varus/valgus alignment of the tibial components of 350 total knee arthroplasties was assessed radiologically. All the tibial components were implanted using an extramedullary guide under the supervision of the senior author. Of components, 96.3% were implanted within 2° of the perpendicular to the longitudinal axis of the tibia. In order to validate our X-ray assessment, a subgroup of 40 knees was re-assessed using a CT scanogram. Analysis of this subgroup showed a close correlation between the results using the two different methods (mean difference 0.88°, S.D. 0.75). We believe that with anticipated future advances in robotic and computer assisted surgery it is important to set the benchmark for what can be achieved with current technology.