Comparative study of adductor canal block versus femoral nerve block for effect on quadriceps muscle strength and postoperative pain in the patients undergoing Total knee replacement surgery

Background: Total knee replacement (TKR) patients experience severe pain during the early postoperative period1 as it involves extensive bone resection and soft tissue manipulation. The objective of this prospective, randomized, comparative study is therefore to compare the adductor canal block (ACB) with femoral nerve block (FNB) on quadriceps muscle strength preservation and analgesic efficacy in the patients undergoing TKR. Material and Methods: Present study conducted in ppatients of age group 35-70 years, ASA physical status class I, II and III patients posted for unilateral TKR. 50 ppatients were randomized equally by block randomization technique. Group 1 received Adductor Canal Block (15 ml bolus of 0.18% ropivacaine followed by infusion at the rate of 8-10ml/hr), Group 2 received Femoral Nerve Block (15 ml bolus of 0.18% ropivacaine followed by infusion at the rate of 8-10ml/hr) with electromechanical infusion pump for 24 Hours. Results: Gender, BMI distribution between two groups doesn’t have significant difference. Out of 50 patients in our study 19.6% (9) patients were ASA I, 75% (39) were ASA II and 5.4% (2) patients were ASA III. Heart rate, systolic blood pressure and diastolic blood pressure were measured preoperatively, post-operative at 6-8 hrs, at 12 hrs. and at 24 hrs. The difference in those parameters at any given time was not statistically significant. ACB is similar to FNB with respect to quadriceps muscle strength measured by MRC grading at 6 hours. However ACB is very effective in preserving the quadriceps muscle strength measured by MRC grading at 12 and 24 hours with a statistically significant ‘P’ value of 0.0001. Conclusion Adductor canal block makes early rehabilitation after total knee replacement without the risk of inpatient falls.