Summary

The aim of this study is to identify the most effective method for postoperative pain management in patients undergoing TKA surgery, through a single periarticular local infiltration analgesia (LIA).

Abstract

Introduction

Pain management after total knee arthroplasty (TKA) remains one of the most important challenges in the immediate postoperative time. Intra-articular local infiltrations have been shown to be effective, especially if performed intraoperatively. Different modalities and substances may be used to obtain pain relief, and no univocal consensus has been reached yet about it.
The aim of this study was to identify the most effective method for postoperative pain management comparing the intravenous opiate infusion protocol to a single periarticular local infiltration analgesia (LIA) in patients submitted to total knee arthroplasty (TKA) surgery.

Methods

50 patients prospectively randomized, mean age 73 years (r. 55-84), undergoing TKA surgery between 2013 and 2015, and were divided into two groups. Group A (25 patients, 4 males and 21 females): intravenous infusion of 20 ml/h of 0,3 mg of Buprenorphine, in 250 cl of normal saline. Group B (25 patients, 7 males and 18 females): single periarticular LIA (2 vials of Ropivacaine 10 mg/dl and 1 vial of Ketorolac 30 mg/dl) during surgery. 1 g of Paracetamol was infused every 6 hours during the day after surgery in both groups. No drainage used. Red blood cells transfusion performed in one patient per group.
For clinical assessment, the Knee Injury and Osteoarthritis Outcome Score (KOOS) pre- and postoperatively at 4 months follow-up (r.2-6 months), the range of motion (ROM) at 40 days after surgery, the Visual Analogue Scale (VAS) were assessed on surgery day, within 1 week and 40 days after surgery were evaluated. Hemoglobin (Hb) and hematocrit (Ht) recorded within 1 week after surgery, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) monitored 40 days after. Statistical analysis performed using Student-t test.

Results

Group A: mean preoperative KOOS score: 40,8 (SD 19,4), postoperative 75,6 (SD 19,5). Mean VAS score on surgery day: 3,2 (r. 0-6) (SD 1,7); VAS score within 1 week: 1,2 (r.0-7) (SD 1,6); VAS after 40 days: 2,1 (r. 0-7) (SD 2,3). Mean ROM after 40 days: 0°-0°-110°. Blood counts after 1 week: Hb 10,9 (r. 8-12,5) (SD 1,1), Ht 31,4 (r. 10,7-37,3) (SD 6,1). Mean ESR after 40 days: 40,4 (r.14-77) (SD 19,1); mean CRP: 5,5 (r. 0,1-36,6) (SD 9,5).
Group B: mean preoperative KOOS score: 42,1 (SD 17,8), postoperative 79,7 (SD 19,7). Mean VAS score on surgery day: 1,1 (r.0-5) (DS 1,8); mean VAS score within 1 week: 0,7 (r.0-6) (SD 1,3); VAS score after 40 days: 1 (r. 0-8) (SD 1,8). Mean ROM after 40 days: 1°-1°-110°. Blood counts within 1 week: Hb 11,8 (r. 9,4-21,1) (SD 2,3), Ht 32,8 (r. 27,5-38,1) (SD 2,9). Mean ESR after 40 days: 35,5 (r. 9-93) (SD 21,3); mean CRP: 4,3 (r. 0,3-16) (SD 4,6).
Student-t test showed no significant difference in functional outcomes and blood counts. A significant difference was reported regarding the VAS of the day of surgery (p value=0,0001). The lower VAS scores in Group B are due to the LIA, prolonging the anesthesia effect in the immediate postoperative hours.

Conclusions

The significant reduction of postoperative pain through the use of LIA enables rapid mobilization and accelerates functional recovery, avoiding several opioid complications and collateral effects.