Fluoroscopic navigation in TKR -Results of a prospective study -CAS-TKR vs. conventional TKR

摘要

Total knee replacement is an often performed surgical procedure in orthopedic surgery. Though the results in the most series show a survivorship of 90-95% after ten years we have to realize that the malalignment resulting from mechanical failure, instability and aseptic loosening is a severe problem in TKR. A valgus/varus deformity up to 3掳 is tolerable due to an acceptable alignment. To reach this aim CAS was established in TKR. Several systems are available, based on CT scan, kinematic and fluoroscopic. Material and Methods: We perform fluoroscopic based navigation with the ion-Station in TKR. A prospective study compares 50 TKR in patients without CAS and 50 patients navigated by the Ion station. The genesis II prosthesis is used in all cases. A cemented TKR of the tibial and femoral component is used in both groups. Two surgeons performed the TKR in the study. The average FU-time in both groups was 9 months (6-12). The questionnaire was performed before, 3 weeks, 3 and 6 months after surgery. X-rays were performed for measurement of the mechanical axis within the same time-table. Results: Age, gender and weight of the patients were in both groups the same. The average time for TKR in the non CAS group was with 67 minutes high-significant shorter than in the CAS-group 1156 minutes. Due to the learning curve the average time for the last 15 patients in the CAS-group was 80 minutes.