Does Computer Navigation Improve the Results of MIS Technique in Total Knee Arthroplasty?

The Minimal Invasive Surgery (MIS) technique used for knee arthroplasty implantation implies a less aggressive surgery and reduces the aesthetic impact. Its most notable disadvantage is the poor visualization of bone structures, which may lead to alterations in the correct placement of the prosthetic components. Navigation-assisted surgery may help avoid such mistakes, and thus navigation coupled with the MIS technique may be an alternative for the future. This is a prospective randomized study of 50 patients who received a total knee arthroplasty. In 25 cases the MIS technique was used, whereas in the other 25 navigation was also employed. Mean age of the patients was 71.63 years, and the mean body mass index was 31.19. Results were assessed based on the definitive radiographic position of the femoral, tibial, and limb axis prosthetic components, as well as according to the Visual Analogue Scale (VAS), the Knee Society Score (KSS), Western Ontarioand McMaster Universities Arthritis Index (WOMAC), Short Form version 12 (SF-12) questionnaires, and the “up-and-go” test. Differences were found between both groups for duration of the procedure (p = 0.0005). No differences were found in the need for analgesics, amount of drained blood, or mean stay time. There were differences regarding the best radiographic position of the tibial component in the navigation group, but not in the final mechanical axis of the limb, even though out-of-range cases were more abundant in the standard-MIS group. At one year after surgery, clinical, functional and quality of life outcomes were similar in both groups. The combined use of surgical navigation and the MIS technique does not yield advantages in terms of limb alignment nor clinical results at one year after surgery.