Comparative study between surgical wound catheter, femoral nerve block, and adductor canal block for postoperative analgesia after knee arthroplasty: A double blind randomized clinical trial

Objectives: The present study compared the surgical wound catheter (SWC), femoral nerve block (FNB), and adductor canal block (ACB) for postoperative analgesia after knee arthroplasty.

Methods: The study included (180) patients scheduled for unilateral total knee replacement and were randomly allocated into three groups. Patients received postoperative analgesia via continuous infusion of ropivacaine 0.2% (10 ml bolus followed by continuous infusion of 5 ml/hour) through the SWC, FNB, or ACB groups. All groups received supplemental analgesia by IV morphine using patient controlled analgesia. Pain scores were assessed at rest and during movements, the worst and least pain scores, and how often were in worst pain during the first 72 hours. The functional activity and patient's satisfaction were also recorded.

Results: The study showed significant reductions in pain scores at rest and during movements in all groups compared to the baseline scores. Significant reductions in pain scores were observed in both ACB and FNB groups compared to the SWC group (P < 0.05). The worst pain scores were (6.15 ± 2.9, 5.85 ± 2.7, and 5.025 ± 1.513), least pain scores (2.06 ± 0.72, 1.92 ± 1.34 and 1.89 ± 1.76), percentage of time in worst pain (17.67 ± 9.15, 11.42 ± 7.50, and 9.8.8 ± 8.14) and the total morphine consumption (39.24 ± 6.82, 34.55 ± 7.86, and 26.40 ± 8.47 mg) in the SWC, FNB, and ACB groups, respectively. Functional assessments and patient's satisfaction, at 6 and 24 hours, were significantly better in ACB followed by SWC, and lastly FNB group (P < 0.5). No significant differences in the incidence of side effects (P > 0.05). Local anesthetic leak from the SWC was a continuous concern by the orthopedic surgeons.

Conclusions: In terms of efficiency, ACB provided the highest quality of analgesia in terms of pain relief, functional activity, and patient's satisfaction. Both ACB and FNB provided higher quality of analgesia compared to the SWC. While ACB and SWC provided better functional improvements compared to FNB.