DIGITAL ASSIST SYSTEM WITHOUT IMAGES FOR TOTAL KNEE ARTHROPLASTY: MULTICENTRIC STUDY OF 821 KNEES

Abstract

Purpose: The purpose of this study was to conduct a multicentric comparison of total knee arthroplasty using the conventional technique versus digitalized navigation.

Material and methods: A prospective comparative study was conducted in five centres in 821 patients using the same implant (Search®, Aesculap, Chaumont): 555 procedures with the Orthopilot® navigation system (Aesculap, tutligen, group 1) and 266 conventional procedures, group 2). Radiographic results were analysed by an independent investigator who examined telemetric images obtained three months after surgery.

Results: The mechanical femorotibial axis was within desired limits (3° frontal deformation) in 88.6% of the knees in group 1 and in 72.2% of the knees in group 2 (p< 0.001). The rate of unacceptable implantations (> 5° deviation) was 2.5% in group 1 and 9.8% in group 2).

Frontal orientation of the femoral component was satisfactory in 89.4% of the knees in group 1 and in 77.1% in group 2. Sagittal orientation of the femoral component was satisfactory in 75.5% of the knees in group 1 and in 70.7% of the knees in group 2. Frontal orientation of the tibial component was satisfactory in 91.9% of the knees in group 1 and in 83.5% of the knees in group 2. The sagittal orientation of the tibial piece was satisfactory in 81.3% of the knees in group 1 and in 69.9% of the knees in group 2. Optimal implantation, considering all criteria studied, was achieved in 275 patients (49.5%) in group 1 and in 82 patients (30.8%) in group 2 (p< à.001). Ther was no difference in results between centres.

Discussion: Computer-assisted navigation facilitated prosthesis implantation with the desired orientation in comparison with manual instrumentation. The number of unacceptable implantations was significantly lower. After a short learning curve, the reliability of this system has proven very satisfactory, facilitating its use since this study.