A comparison of robotic-assisted and manual techniques in restricted kinematically aligned total knee arthroplasty: coronal alignment improvement with no significant clinical differences

Purpose The purpose of this study was to compare radiographic and clinical outcomes of robotic-assisted and conventional manual techniques in restricted kinematically aligned TKA. Methods Patients who underwent either manual or robotic-assisted restricted kinematically aligned TKA between 2019 and 2020 were included in this retrospective comparative study. Radiographic outcomes comprised coronal plane measurements performed through standing full-length anteroposterior radiographs. The Knee Injury and Osteoarthritis Outcome Score (KOOS), Oxford score, Visual Analog Scale pain and satisfaction score, and Forgotten Joint Score were used to determine the clinical outcome. The continuous data were compared by Student’s t test according to the Kolmogorov‒Smirnov normality test. Results The manual group consisted of 46 patients (38 females, eight males) with a mean age of 68.1 years, and the robotic group consisted of 70 patients (58 females, 12 males) with a mean age of 65.7 years (n.s.). Preoperatively, no significant difference was observed between groups concerning demographic characteristics, radiographic measurements, and clinical scores except for the symptom and pain domains of the KOOS score, which was significantly worse in the manual group ( p = 0.011 and 0.035, respectively). At the postoperative 2-year follow-up, we observed significant differences between groups with respect to the mean HKA angle, mMPTA, and mLDFA ( p = 0.034, 0.041, and 0.005, respectively). A comparison of clinical scores at the postoperative 2-year follow-up demonstrated no significant differences between groups. Conclusion The current study demonstrated that using robotic-assisted technique for restricted kinematically aligned total knee arthroplasty (TKA) resulted in significantly better outcomes compared to the conventional manual technique in achieving normal ranges of lower extremity coronal alignment measurements. While the robotic-assisted group demonstrated better clinical scores, there was no statistically significant difference in clinical outcomes between the robotic-assisted group and the control group at the two-year follow-up. Concerning clinical relevance, the restoration of original anatomy and coronal alignment, a crucial concern in restricted kinematically aligned TKA, may be better achieved by the robotic-assisted technique. Level of evidence Level III (Retrospective cohort study).