Abstract
Aims: Because of the limitation of exposure inherent in minimally invasive surgical techniques for total knee replacement surgery, there is a significant risk of malalignment, malrotation, femoral notching and failure of soft tissue balance.
Methods: In this randomized study 50 patients with osteoarthritis of the knee, underwent TKR through a minimally invasive exposure using a navigation system; while a control group of 50 patients underwent the same surgery without navigation.
A subvastus approach was used with a less than 10 cm incision. Femoral component alignment is established with an intramedullary, and the tibial component, with an extramedullary alignment guide. The navigation system was used for fine adjustment and verification of cutting block position. The navigation system used for the study was the VectorVision® CT-Free Knee 1.5.1.
Results: The accuracy of prosthetic components positioning was significantly higher in the navigation group. The navigation system offered an objective analysis of medial and lateral ligament tension in full extension and 90 ° of flexion. In 8 cases navigation avoided femoral notching. No navigation related complications were registered. The additional surgery time for computer-assisted TKR was a mean 21 minutes. The nonnavigated implantation technique reached perfect component positioning in 62 % of the TKR.
Conclusion: Computer-assisted TKR results in predictable and accurate alignment, avoidance of femoral notching, avoidance of malrotation and appropriate balance of the soft tissue. Performing minimally invasive TKR without navigation has a higher risk of increased rate of unsatisfactory outcomes with shorter prosthetic survivorship when compared to the use of navigation.
Correspondence should be addressed to Ms Larissa Welti, Scientific Secretary, EFORT Central Office, Technoparkstrasse 1, CH-8005 Zürich, Switzerland
