Buprenorphine added to bupivacaine prolongs femoral nerve block duration and improves analgesia in patients undergoing primary total knee arthroplasty-a randomised prospective double-blind study.

The aim of the study was to determine whether the addition the long-acting opioid buprenorphine as an adjuvant to the local anaesthetic agent would improve quality and prolong duration of femoral nerve blockade in post-operative analgesia following primary total knee arthroplasty. The study involved 48 patients. The femoral nerve was anaesthetised with a 0.25% solution of bupivacaine with adrenaline or with the addition of 0.3mg of buprenorphine. The duration of the sensory block and analgesic effect was assessed according to NRS scale at 12, 24, 36, 48, 60 and 72 hours post-surgery. Patients who received buprenorphine as an adjuvant to the local anaesthetic had significantly longer sensory blockade and lower NRS-rated pain intensity with the difference reaching statistical significance at 12 hours post-surgery.