Long-term outcomes of computer-assisted Ci™ navigation versus conventional total knee arthroplasty

The aim of this study was to investigate the long-term effects of computer-assisted Ci™ navigation on clinical, radiological, and functional results versus conventional total knee arthroplasty (TKA).

Between January 2005 and July 2011, a total of 85 patients (36 males, 49 females; mean age: 66.2±5.2 years; range, 59 to 84 years) who underwent P.F.C. Sigma™ knee system implantation using computer-assisted Ci™ navigation system (BrainLAB®, DePuy International, Leeds, UK) and completed a minimum follow-up of eight years were included in the study. In the control group, a total of 100 patients (40 males, 60 females; mean age: 68.3±3.9 years; range, 60 to 79 years) who completed a minimum follow-up of eight years were randomly selected from a dataset of implanted P.F.C. Sigma™ knee systems in the same period using Specialist® 2 instrumentation without navigation. An implant survival analysis was used to compare implant survivorship between the groups throughout 12 years. The Knee Society Score (KSS) and range of motion (ROM) were assessed. Based on long-format X-ray images, the implant position in the frontal and sagittal planes was evaluated.

The ratio for navigation to control group survival is approximately 1.01 at 12 years. The clinical outcomes showed no significant difference between the groups (knee scores, p=0.707 and functional scores, p=0.485). In the measured angles analysis, we observed a consistent pattern in both groups. In the control group, there was a trend toward implanting the tibial component with slight varus alignment (p=0.038) and a higher posterior slope (p<0.001). On average, the operation was prolonged by 13 min in the navigated group (p<0.001).

In conclusion, our study results demonstrate that while kinematic navigation in TKA improves the precision of implant alignment, it does not provide significant benefits in terms of long-term implant survival or functional outcomes compared to conventional TKA methods. The use of the computer-assisted Ci™ navigation system is associated with prolonged operation duration, although no technical complications related to the navigation device's software can be observed. Therefore, although navigation offers theoretical advantages in component positioning, its use may be more justifiable in cases with challenging alignment requirements rather than as a routine practice.