Randomized prospective comparative study of adductor canal block versus periarticular infiltration on early functional outcome after unilateral total knee arthroplasty

Background: Total knee arthroplasty (TKA) is associated with significant post-operative pain. Effective pain relief is essential for early post-operative rehabilitation. Periarticular infiltration (PAI) and Adductor canal block (ACB) have become popular modes of pain management after TKA. Our aim is to compare their efficacy and impact on early functional outcome in patients undergoing TKA.

Methods: A single-blind randomised controlled trial, 100 patients undergoing unilateral primary TKA for symptomatic OA were allocated to either of the two groups (50 in each arm). Postoperative ultrasound guided single shot of ACB (Group A) or intra operative PAI (Group B). All patients underwent TKA without patella resurfacing under spinal anaesthesia. Pre-operative work up, surgical technique, post-operative management were standardised for all the patients. Patients were assessed for pain using VAS (Visual analogue scale) at 6, 12, 24 hrs after surgery, haemoglobin level preoperatively and post operatively on day 1 to calculate blood loss, hospital stay, tourniquet time (TT), operative time (OT) and post-operative complications by an independent observer blinded to the group allocation.

Results: Patients were matched for age, gender, ASA grade and Deformity. VAS (scale 0-10) between PAI & ACB at 6, 12 & 24 hours were significantly different (p<0.05) with higher score seen in the patients with ACB at all time points. TT and OT were significantly longer in the PAI than ACB. No significant difference in the hospital stay observed. No complications occurred during the study.

Conclusion: PAI achieves better pain control as compared to ACB in patients undergoing unilateral TKA.