Accuracy of implantation during computer-assisted minimally invasive Oxford unicompartmental knee arthroplasty A comparison with a conventional instrumented technique

The prognosis of unicompartmental knee arthroplasty (UKA) is strongly associated with the accuracy of the component alignment To determine the accuracy of navigated UKA during primary minimally invasive Oxford UKA twenty-nine knees of 29 consecutive patients (Group A) Implanted using conventional instrumented UKA were followed by 23 knees of 17 consecutive patients (Group B) implanted by navigation assisted UKA and radiological results regal ding alignments of the femorotibial mechanical axis femur and tibial component were compared in the two groups Assessments of mechanical limb alignment revealed statistically significant Increases in mechanical limb alignment post-operatively in both groups (p = 0 0 for both) In terms of component alignment Group B had more prostheses implanted in the satisfactory range (>+/- 3 from the targeted values) for the femoral and tibial components than Group A There were no significant differences in the rate of prosthesis Implanted within the range of radiographic alignment variations for the coronal implantation of either femoral or tibial components in both groups (Radiographic alignment variation coronal orientation of femoral components 90 +/- 10 sagittal orientation of femoral components 90 +/- 5 coronal orientation of tibial components from 10 varus to 5 valgus sagittal orientation of tibial components from 7 of posterior tibial flexion to 5 of anterior tibial flexion) However significant increases in the accuracies of sagittal implantation of femoral and tibial components were observed in Group B versus Group A Our data suggest that navigated implantation improves the accuracy of the radiological implantation of the Oxford UKA prosthesis without increasing complications versus conventional UKA (C) 2009 Elsevier B V All rights reserved