Effectiveness of Periarticular Local Infiltration Analgesia in Primary Total Knee Arthroplasty: A Retrospective Case Series

Background Periarticular local infiltration analgesia (LIA) is widely used within multimodal and enhanced recovery after surgery (ERAS)-based pathways for total knee arthroplasty (TKA). However, real-world data remain heterogeneous, particularly regarding simplified injection regimens without adjuvants. This study aimed to describe early postoperative outcomes following a standardized periarticular LIA protocol in primary TKA. Methods This retrospective single-center case series included 30 consecutive patients undergoing primary TKA for knee osteoarthritis between January and June 2025. All patients received spinal anesthesia and a standardized three-stage periarticular infiltration protocol using diluted bupivacaine and lidocaine without adjuvants. Outcomes were analyzed descriptively and included visual analog scale (VAS) pain scores, documented opioid administration, time to mobilization, length of stay, complications, and patient satisfaction. Results The mean age was 72.2±7.3 years, and 73.3% of patients were women. Postoperative pain, assessed using the visual analog scale (VAS, 0-10), demonstrated a progressive decrease over the first 48 hours following surgery. At six hours postoperatively, the mean VAS score was 2±1 for all patients (n=30). At 12 hours, the mean VAS increased to 4±1, followed by a reduction to 3±1 at 24 hours, and further decreased to 1±1 at 48 hours. No postoperative opioid administration was documented in the reviewed medical records. Early mobilization occurred at 12 hours, with progressive functional recovery and a mean hospital stay of four days. No major complications or signs of local anesthetic systemic toxicity were observed. Patient satisfaction was high (93.3% satisfied or very satisfied). Conclusion This retrospective case series describes the implementation of a standardized periarticular LIA protocol associated with low early postoperative pain scores and favorable short-term recovery outcomes within a multimodal and ERAS-based pathway. Due to the retrospective design and absence of a control group, comparative efficacy cannot be established, and findings should be interpreted as descriptive and hypothesis-generating. Prospective controlled studies are required to evaluate its effectiveness against contemporary motor-sparing regional anesthesia techniques.