Impact of the surgical workflow and technology change on early clinical outcomes in total knee arthroplasty.

Abstract

Total knee arthroplasty (TKA) encompasses diverse surgical workflows that vary in bone cut sequencing and alignment strategies. This study evaluates the impact of transitioning from femur-first measured resection (MR) to tibia-first gap balancing (GB) using the same computer-assisted orthopaedic surgery system (CAOS). The clinical and technical impact of this transition was assessed across two phases of GB adoption to capture effects of surgical learning and workflow adaptation. A retrospective review was conducted on 225 TKA cases performed by a single senior surgeon. Patients were grouped into three cohorts: (1) MR (75 cases), (2) GB early (first 75 GB cases), and (3) GB late (subsequent 75 GB cases). All cases used the same CAOS system and GB cases utilized a force-controlled distractor integrated into the CAOS system to acquire dynamic joint gap data for full-arc-of-motion. KOOS Jr. scores were collected preoperatively and at one-year follow-up. Intraoperative parameters including femoral and tibial alignment, tibia slope, tibial insert thickness, and planned and checked joint gaps were analyzed. Postoperative KOOS Jrimprovement was highest in the GB late cohort (34.1 ± 20.9), significantly greater than both MR (27.3 ± 15.8, p = 0.025) and GB early (27.7 ± 16.1, p = 0.036). MR and GB early were not significantly different (p = 0.89). Compared to MR, GB cohorts showed greater variability in femoral resection parameters, along with increased femoral flexion and tibial slope. From GB early to GB late, there was a clear refinement in technique, with GB late demonstrating significantly tighter and more consistent medial and lateral gaps. Transitioning to a tibia-first GB workflow with a force-controlled distractor enabled more precise and individualized gap management, leading to improved clinical outcomes. While early GB clinical outcomes were comparable to MR, continued use of the GB technique was associated with refined surgical execution and superior clinical outcomes.