Comparable clinical outcomes in functionally aligned computer-assisted and image-based robotic assisted total knee arthroplasty

Purpose: To determine the clinical outcomes differences and complications in two comparable groups of patients undergoing computer aided surgery (CAS) and robotic-assisted (RA) posterior stabilised (PS) total knee arthroplasty (TKA) following functional alignment (FA) principles with tibial pre-cut at a minimum of 4-year follow-up. Methods: This retrospective, monocentric and observational study included 94 consecutive patients undergoing PS TKA performed with CAS and RA-TKA following FA principles, between January 2017 and January 2020. Patients were followed with radiological and clinical assessment and evaluated with the Forgotten Joint Score-12 (FJS-12), Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and the 5-Level Likert Scale (5-LLS). Results: Out of 94 patients two were lost to follow-up and one deceased in the robotic branch, eight patients were lost to follow-up and two were deceased in the navigated branch. Hereby, a total of 84 patients (87 knees) with a mean age of 69.2 ± 8.4 years were considered. A total of 40 cases were included in the CAS group; 44 cases were included in the RA-TKA group. No revisions were performed in any of the two groups, resulting in an overall Kaplan-Meyer survivorship rate of 100% for both cohorts. At last follow-up, no statistically significant differences were recorded between CAS and RA-TKA relative to FJS-12, KOOS-JR and 5-LLS (FJS-12: 89.4 ± 9.5 vs 88.3 ± 13.4; KOOS-JR: 88.0 ± 10.2 vs 86.2 ± 11.5; 5-LLS 4.4 ± 1.7 vs 4.6 ± 2.1) respectively. Conclusions: No significant outcomes differences and complications were detected between patients undergoing PS-TKA performed with either CAS and RA at a minimum 4-year follow-up. TKA performed with a patient-specific FA technique and with a soft tissue-preserving approach, showed excellent results with both CAS and RA-TKA. Level of Evidence: Level III.