Twelve-Year Follow-Up of Navigated Computer-Assisted Versus Conventional Total Knee Arthroplasty: A Prospective Randomized Comparative Trial

Abstract

Background: Navigated computer-assisted total knee arthroplasty (TKA) was introduced to expedite long-term survival based on improved postoperative implantation accuracy. However, long-term outcome data after 10 years or more are rare, even available meta-analyses show controversial study results.

Methods: In a prospective randomized trial, 100 conventional TKAs (group CONV) were compared with 100 computer-assisted TKAs (group NAV) after a mean follow-up of 12 years postoperatively. A long-leg weight-bearing X-ray was performed for measuring mechanical axis of the limb, lateral distal femoral angle, and medial proximal tibial angle. Tibial slope, patella alpha angle, and radiolucent lines were also observed. Clinical investigation included evaluation of 4 different scores: Insall Knee Score, Western Ontario and MacMaster University Index score, Hospital for Special Surgery Knee Score, and visual analog scale.

Results: Based on a follow-up rate of at least 75%, no difference in TKA survival was found 12 years postoperatively: 91.5% in group CONV vs 98.2% in group NAV (P = .181). Since 5-year follow-up, no additional TKA revision had been performed in both groups. Group CONV showed a nonsignificant higher inaccuracy of neutral lower limb axis (1.8° ± 1.4°) compared to group NAV (1.6° ± 1.7°, P = .700). All X-ray assessments were not significant different within both study groups (P ≥ .068). Clinical examination showed no differences in evaluations (P ≥ .204). All collected outcome score results were similar (P ≥ .222).

Conclusion: Twelve years postoperatively, no differences were found in terms of long-term survival, implantation accuracy, clinical outcome or score results.

Keywords: 12-year follow-up; TKA; comparison; computer-assisted; conventional; navigation.