Comparative Analysis of Image-free Navigation System-Assisted TKA and Conventional TKA

ABSTRACT

PURPOSE: To compare the roentgenographic results between Image-free navigation system-assisted total knee arthroplasty (TKA) using the OrthoPilot(R) and conventional TKA. MATERIALS AND METHODS: Of 120 primary TKA that operated by one surgeon, 60 cases were operated with a Image-free navigation system (OrthoPilot(R) 4.0, Aesculap, Tuttlingen, Germany) (group A) and 60 cases were operated with conventional method (manual alignment system) (group B). The alignment of the lower extremity and the position of the components were determined on postoperative long-leg standing anteroposterior radiogram and lateral radiogram. RESULTS: Mechanical axis was significantly more accurate in group A than group B(95% compared with 80%). The coronal inclination of femoral component to mechanical axis (theta) was significantly more accurate in group A than group B(96.7% compared with 80%). There were no significant differences between two groups in the sagittal inclination of femoral component(gamma), the coronal inclination of tibial component (beta) and the sagittal inclination of tibial component(delta). In all five measurements being excellently implanted, a significantly higher number was in group A(60% compared with 40%). CONCLUSION: Image-free navigation system-assisted TKA using the OrthoPilot(R) led to significantly increased precision of restoration of the alignment of the lower extremity and the position of the components compared with the conventional method. Potential benefits in long-term outcome and functional improvement require further investigation.