Postoperative Analgesia after Total Knee Arthroplasty: a Comparative Analysis of Current Treatment Techniques Effectiveness

The objective of the study was to evaluate the effectiveness and safety of high-volume local infiltration and epidural analgesic techniques after primary total knee arthroplasty versus standard systemic multimodal analgesia in the context of the postoperative analgesia protocols.

Materials and Methods. A single-center randomized comparative study included 84 patients who, from august 2017 to august 2018, underwent a primary total knee arthroplasty. Depending on the method of postoperative analgesia, we randomized patients into 3 groups. Group A consisted of 32 patients who received intraoperative infiltration of periarticular tissues with 0.2% solution of ropivacaine in combination with adrenaline and subsequent bolus injection of a local anesthetic solution via a catheter inserted into the wound. Group B included patients who received epidural analgesia with a constant infusion of a 0.2% solution of ropivacaine (n = 28). In patients of group C, neither regional nor local analgesia techniques were used for postoperative analgesia (n = 24). All patients received standard systemic multimodal analgesia using nonsteroidal anti-inflammatory drugs and tramadol. The pain intensity was measured by vas when the patient was motionless, and during knee flexion (before surgery, after surgery on resolution of motor block and during the initial postoperative 24 h), side-effects were recorded.

Results. The patients of Group C, during knee flexion in the postoperative period, reported the highest pain scores (6 (5; 8) during the initial postoperative 12 h and 6 (5; 6) during the initial postoperative 24 h). Severe pain, resistant to therapy and requiring the administration of narcotic analgesics (morphine 1.0 mg), was noted in 5 (15.6%) patients in group A and in 10 (41.6%) in group C, in contrast to patients of group B, where no pain was recorded in any patient, p = 0.056, p = 0.037 and p<0.0001. Hypotension was observed only in group B in 6 (22%) patients. Intra-articular and other infectious complications among all patients were not recorded.

Conclusion. High-volume local infiltration analgesia as a modality of postoperative analgesia is not inferior in the effectiveness to the epidural analgesia, does not require strict monitoring and is accompanied by a lower incidence of side-effects and complications, which can make it the procedure of choice in multimodal analgesia schemes for total knee arthroplasty.