A prospective comparative study of local infiltration versus adductor block versus combined use of the two techniques following knee arthroplasty.

BACKGROUND

Pain management after total knee arthroplasty (TKA) is important as acute postoperative pain can affect patient's ability to walk and participate in rehabilitation required for good functional outcome. This is achieved by effective intra-operative and post-operative analgesia to facilitate early recovery. Adductor canal block (ACB) and local infiltration analgesia (LIA) are analgesic regimens and commonly used for effective post-operative analgesia after TKA. Our aim was to compare the efficacy and outcomes of these two methods, combined and independently.

METHODS

Our study included 120 patients undergoing unilateral TKA, who were randomized into three groups: LIA (Group I), ACB (Group II) and combined LIA + ACB (Group III). Patients were operated by a single surgeon. The outcome was defined by post-operative analgesia achieved by the three techniques (measured by the NPRS) and amount of fentanyl consumed postoperatively. Secondary outcome was evaluated based on postoperative functional outcomes in terms of ability to stand, distance covered, range of motion of knee on the 1st post-operative day, complications and WOMAC (Western Ontario & McMaster Universities Osteoarthritis Index) scores.

RESULTS

All patients were available for analysis. Numerical Pain Rating Scale for pain showed significant differences at 24 h between Group I and Group II, with a p value of 0.018 (GroupI was better), significant differences were found at 24 h between Group III and Group II, with p values being 0.023 and 0.004 (GroupIII was better). No significant differences were found between Group I and Group III at 24 h. Total fentanyl consumption was significantly less in Group III than in Group I and Group II, with p value being 0.042 and 0.005, respectively (Group III was better and consumed less fentanyl). No significant differences were found in WOMAC scores between the three groups at baseline, 2 and 6 weeks after operation.

CONCLUSION

In patients undergoing TKA, analgesic effect of combined ACB and LIA was superior, as indicated by reduced opioid consumption and no differences in functional outcomes and complications were observed as compared to separate use of the two techniques.