Minimally invasive navigation-assisted versus conventional total knee arthroplasty: a meta-analysis

Purpose: It is unclear whether the minimally invasive navigation-assisted (MINA) or conventional (CONv) approach for primary total knee arthroplasty (TKA) leads to better clinical and radiographic outcomes. This meta-analysis compared the clinical and radiographic outcomes of the MINA and CONv approaches after primary TKA. It was hypothesized that there was no difference in clinical and radiographic outcomes between the two surgical approaches for primary TKA. Methods: This meta-analysis reviewed all studies that compared surgical time, incision length, flexion range of motion (ROM), Knee Society Score (KSS), coronal mechanical axis (CMA), and coronal femoral component angle (CFCA) with various measurement tools, from direct interview to plain radiography, between the MINA and CONv approaches. Results: Five studies met the inclusion/exclusion criteria for the meta-analysis. The findings of this study suggest that surgical time (95 % CI −18.51 to 39.09; n.s.), KSS (95 % CI −8.55 to 30.84; n.s.), CMA (95 % CI −1.01 to 0.54; n.s.), and CFCA (95 % CI −0.91 to 2.97; n.s.) were similar between the two surgical approaches, whereas incision length (95 % CI −5.18 to −3.69; P < 0.001) was significantly shorter in the MINA approach and flexion ROM (95 % CI 14.26–19.01; P < 0.001) was significantly greater in the MINA approach. Conclusions: There were no significant differences in clinical and radiographic outcomes, including surgical time, KSS, CMA, and CFCA, in patients who underwent MINA and CONv approach for primary TKA, but the MINA approach resulted in a slightly shorter incision length and increased flexion ROM than the CONv approach. Therefore, if particular attention has to be paid to patient’s selection with appropriate counselling and surgeon’s experience, MINA approach can provide early clinical benefit when compared with CONv approach. Besides, orthopaedic surgeons need to master the MINA and CONv approaches because both approaches have similar clinical and radiographic outcomes. Level of evidence: Therapeutic study, Level II.