Comparison of Minimally Invasive Unicompartmental Knee Arthroplasty With or Without a Navigation System

The authors investigated the hypothesis that navigation system–assisted minimally invasive unicompartmental knee arthroplasty (NA-MIS UKA) produces better short-term clinical results than MIS UKA without a navigation system. After a minimum 2-year follow-up, short-term functional results and component alignment accuracies of 31 knees that underwent NA-MIS UKA (the NA-MIS group) were compared with those of 33 knees that underwent MIS UKAs without a navigation system (the MIS group). The Hospital for Special Surgery and Western Ontario and McMaster Universities Osteoarthritis Index scores of 2 groups showed significant improvement at final follow-ups, but no significant intergroup differences were observed (P = .071 and P = .096, respectively). However, NA-MIS UKA produced more improvement in the desired mechanical axis and a lower percentage of prosthetic alignment outliers than MIS UKA.