Comparison of total knee arthroplasty using computer-assisted navigation versus conventional guiding systems: a prospective study.

PURPOSE To compare knee alignments in total knee arthroplasty (TKA) using computer-assisted navigation versus conventional guiding systems. METHODS Five men and 49 women aged 49 to 79 years underwent TKA for primary osteoarthritis of the knee with varus deformity. All valgus knees were associated with inflammatory arthritis and thus excluded. Computer-assisted navigation was used for the first 35 TKAs, whereas conventional extramedullary tibial and intramedullary femoral guiding systems were used for the next 35 TKAs. The mechanical axis, coronal tibial and femoral angles, sagittal tibial and femoral angles in the 2 groups were compared. RESULTS Sagittal tibial and femoral angles aligned more optimally in TKAs using computer-assisted navigation. In the respective computer-assisted navigation and conventional guiding systems, 33 (94%) and 26 (74%) of the TKAs attained a postoperative mechanical axis of <3 degrees varus/valgus. CONCLUSION Computer-assisted navigation gives a more consistent alignment correction and reduces outliers during implant positioning.