Comparison of the radiographic results of total knee arthroplasty with or without using electromagnetic navigation / 中华骨科杂志

ABSTRACT

Objective To compare the lower limb alignment and prosthesis position after total knee arthroplasty (TKA) with or without using electromagnetic navigation.Methods Sixty-four patients (100 knees) underwent TKA under electromagnetic navigation,while 62 patients (100 knees) underwent conventional TKA.Three months after operation,the mechanical axial line angle and prosthesis position (angels α,β,γ) were measured via the full-length radiograph of both lower limbs and anteriorposterior and lateral Xrays of the knee.Results The average mechanical axial line angle and angle α were 1.20°±1.92°and 89.33°±1.64° in navigation group,respectively,and 2.31°±2.25° and 88.68°±2.57° in conventional group.And the differences were significant with regard to the above two indexes between two groups.The average angle β and angle γ were 89.64°±1.47° and 90.86°±2.37° in navigation group,respectively,and 89.26°±2.05° and 90.59°±3.44° in conventional group.However,the differences were not significant with regard to the above two indexes between two groups.After operation,mechanical axial line angle error was within ±3°in 86％ of patients in navigation group,while in 79％ of patients in conventional group; there was no significant difference between them.The angle α error was within 90°±3° in 92％ of patients in navigation group,while in 77％ of patients in conventional group; there was significant difference between them.However,there were no significant differences in percentage of patients whose errors of angle β and angle γ were within 90°±3° between two groups.Conclusion With using electromagnetic navigation in TKA,more precise prosthesis position and the mechanical axis can be achieved compared with the conventional technique.And its advantages mainly contribute to the coronal plane of the femoral side rather than the tibial side.