Percutaneous intra-articular injections of ropivacaine, and tranexamic acid and removal of the drainage tube one day after total knee arthroplasty as a component of enhanced recovery after surgery: a randomized control trial

Background: Intraoperative injections of ropivacaine and tranexamic acid have an increasing role as part of analgesia and haemostasis for enhanced recovery after Total Knee Arthroplasty. However, drug efficiency gradually disappears one day after surgery. Drainage tube placed for too long can cause various complications. This study evaluates whether the postoperative injections of ropivacaine, and tranexamic acid and removal of the drainage tube one day would promote recovery after TKA. Methods: A total of 80 participants were randomly assigned to two groups. One group was treated with additional intra-articular injections at 08:30 on postoperative day 1 and the removal of drainage tube simultaneously (Trial Group). Another group was dealt with no injection and removal of the drainage tube responding to the amount of drainage fluid (Control Group). The multi-drug solution included 100 mg ropivacaine, and 1 g tranexamic acid, and 10 mL saline. The primary outcomes assessed included visual analog scale score, length of hospital stay after surgery, the circumference of the knee, total blood loss volume. Results: The group that received an additional intra-articular injection of ropivacaine had a significantly lower area under the curve for visual analog scale score than the no injection group at rest (424 ± 32 compared with 515 ± 39, p = 0.003). The Trial Group can reduce the length of hospital stay after surgery over the Control Group (7.1 ± 3.1 days compared with 8.7 ± 3.2 days, p = 0.003). The group that received an additional intra-articular injection of tranexamic acid have no difference in total blood loss volume & the circumference of knee joint over the no additional intra-articular injection group (910.6 ± 385.3 mL compared with 974.8 ± 408.2 mL, p=0.47 & 38.9 ±5.4cm compared with 38.8±2.4cm，p=0.91). Conclusions: Intra-articular injection of ropivacaine, and tranexamic acid and removal of the drainage tube one day after TKA can further promote recovery after TKA. Keywords: enhanced recovery after surgery, total knee arthroplasty, tranexamic acid, ropivacaine