Comparative Efficacy of General and Regional Anesthesia in Total Knee Arthroplasty: A Single-Center Prospective Patient- And Assessor-Blinded Randomized Trial

BACKGROUND: Total knee arthroplasty (TKA) is associated with significant postoperative pain. It is assumed that implementing regional anesthesia techniques, such as adductor canal block (ACB) and infiltration of the space between the popliteal artery and femoral condyle (iPACK), may reduce postoperative pain intensity and, consequently, attenuate the surgical stress response. AIM: Comparative assessment of the analgesic efficacy, safety, and impact on the stress response of regional versus general anesthesia in primary total knee arthroplasty. METHODS: The study included 118 TKA patients, divided into three groups: I – general anesthesia (GA); II – femoral nerve block (FNB) combined with spinal anesthesia (SA); III – iPACK+ACB combined with SA. Pain intensity was assessed using the visual analog scale (VAS), serum cortisol and interleukin-6 levels were measured, opioid consumption was recorded, postoperative recovery quality was evaluated using the QoR-15 scale, and the incidence of chronic pain (CPS) was monitored. RESULTS: Pain intensity in Group I was higher compared with other groups at all time points (p=0,000). In Group II, pain levels at 12, 36, 48, and 72 hours exceeded those in Group III (p2,3=0,015; 0,001; 0,008; 0,000, respectively). Breakthrough pain episodes occurred in 13.98% of patients in the GA group and 5.71% in the FNB group. Cortisol levels on postoperative days 1 and 3 were significantly higher in Groups I and II (p1,3=0,001 at POD 0; p1,3=0,000, p2,3=0,000 at POD 1; and p1,3=0,000, p2,3=0,000 at POD 3). IL-6 concentrations were also lower in Group III on POD 1 and POD 3 (p1,3=0,001, p2,3=0,002; and p1,3=0,000, p2,3=0,000, respectively). Patients receiving iPACK+ACB demonstrated superior functional recovery scores. The time to first opioid request was 5.75 times longer in Group III than in Group I, and twice as long in Group II compared to Group I. No adverse events were recorded. The incidence of CPSP was 16.51% at 3 months, 11.93% at 6 months, and 10.09% at 12 months postoperatively. CONCLUSION: Regional anesthesia for total knee arthroplasty, specifically the combination of spinal anesthesia with iPACK+ACB blocks, is an effective perioperative analgesic technique and a strategic approach that limits the body’s stress response and reduces the risk of chronic pain in the future.