This study was performed to evaluate the effect and complications of an intraoperative regional analgesic injection in primary total knee replacement arthroplasty (TKRA).

As a prospective study, 50 patients who underwent bilateral TKRA were injected with 50 cc of mixed analgesics (morphine, norepinephrine and epinephrine) into the joint capsule, muscles around the knee joint on one side (study side) and the same amount of the normal saline on the other side (control side) before closure. The level of postoperative pain was evaluated in the visual analogue scale (VAS) at postoperative 4 hours, 12 hours, 1, 2, 4, 7, 14 days. The range of motion at postoperative 4, 7, and 14 days, the amount of hemovac drainage and the patients preference were also evaluated.

There was a significant decrease in the VAS on the study side at postoperative 4 hours, 12 hours and 1 day (p<0.05). There was no difference in the VAS thereafter. Patients preferred the injection site in 90% (45 side). The ROM at 4, 7, 14 days and hemovac drainage were similar in both sides (p>0.05).

An intraoperative regional analgesic injection in primary TKRA is effective in reducing the level of acute postoperative knee pain with minimal complications with the majority of patients preferring it.