Comparison Of The Results Between Conventional And Navigated Simultaneous Bilateral Total Knee Arthroplasty

ObjectiveTo compare the radiological and clinical results of simultaneous bilateral total kneearthroplasties between computer-assisted-navigation and conventional total kneearthroplasties.MethodsWe prospectively compared the clinical results of primary TKAs using navigationsystem and primary TKAs using conventional technique. Simultaneous bilateral total kneearthroplasties were carried out in36patients (72knees). One knee was replaced with useof a computer-assisted surgical navigation system, and the other was replacedconventionally without use of computer-assisted surgical navigation. Radiologicalevaluations were conducted at6weeks postoperatively. To compare the radiographicresults, the following parameters were measured: mechanical femorotibial angle, coronal femoral component angle, coronal tibial component angle, sagittal femoral componentangle, and sagittal tibial component angle. VAS scores were conducted at5dayspostoperatively. Short-Form12scores and KSS scores were obtained at6weeks,6months, and12months postoperatively.ResultsThe navigation TKA showed better accuracy and precision in mechanical axis(1.19°±1.56°), coronal femoral component angle(90.60°±1.75°) and sagittal femoralcomponent angle(-0.35°±1.45°)(P<0.05). Ten knee implants (27.8%) in the conventionalgroup, compared with three knee implants (8.3%) in the navigation group, deviated>3°from the mechanical axis in the coronal plane. Prior femoral mechanical-anatomic anglewas significantly associated with coronal femoral component angle in the conventionalgroup. Inversely, there was no significant association between both variables in thenavigation group. No significant difference between groups with respect to the tibialcomponent position (P>0.05). Prior coronal tibial angle was significantly associated withcoronal tibial component angle in both groups. Patients in the navigation group hadsuperior VAS scores at3days postoperatively. The SF-12scores and KSS scores at allintervals from6weeks were not significantly better for patients in the navigation group.ConclusionThis study provides evidence that limb alignment and femoral component alignmentwith computer-assisted total knee arthroplasty, as measured with radiography, aresignificantly improved compared with that associated with conventional surgery.Modification of the computer-assisted technique for cutting is required when remarkableanatomic variation such as femoral bowing and tibial varus are observed on preoperativeradiographs. Computer-assisted technique can significantly relieve pain in the duration ofhospital stay. Whereas there seems to be increasing evidence that navigation in total kneearthroplasty is able to improve the alignment for the patients, there are no accessible dataon the clinical results after such a procedure.