Clinical and Radiological Outcomes of Computer-Assisted Navigation in Primary Total Knee Arthroplasty for Patients with Extra-articular Deformity: Systematic Review and Meta-Analysis.

Background: Computer-assisted navigation surgery (CAS) during primary total knee arthroplasty (TKA) may help improve outcomes for patients with extra-articular deformity (EAD); however, this has not been extensively studied. Therefore, we aimed to investigate the clinical and radiological outcomes following primary TKA using CAS in patients with EAD. Methods: We searched Medline, Embase, and the Cochrane Library up to March 3, 2023 for studies investigating surgical outcomes of using the navigation system for TKA to treat patients with EAD. From 14 studies, 539 knees with EAD that underwent navigation TKA were enrolled. We investigated the knee range of motion (ROM), outcome scores at final follow-up (Knee Society Score [KSS] and Knee Functional Score [KFS]), and pre- and postoperative mechanical hip-knee-ankle (mHKA) angle using lower extremity scanogram. The meta-analysis was based on the single-arm method, and all data were pooled using a random-effects model. Results: Following our meta-analyses, the mean knee ROM changed from 87.0° (95% confidence interval [CI], 75.9°-98.1°) preoperatively to 109.4° (95% CI, 97.9°-120.8°) postoperatively. The adjusted KSS was 93.45 points (95% CI, 88.36-98.54 points), and the adjusted KFS was 91.57 points (95% CI, 86.80-96.33 points) in knees with EAD that underwent CAS-TKA. As a radiological outcome, the mHKA angle changed from 169.53° (95% CI, 166.90°-172.16°) preoperatively to 178.81° (95% CI, 178.31°-179.30°) postoperatively. Conclusions: CAS-TKA yielded positive clinical results and demonstrated a satisfactory alignment of the lower limb's mechanical axis. CAS-TKA showed promise for primary TKA procedures, demonstrating favorable clinical and radiological outcomes even in complex cases involving EAD.