Pain trajectory after total knee arthroplasty (TKA) with prolonged use of outpatient adductor canal catheters.

Background: In this prospective observational study, we sought to evaluate whether the prolonged use of adductor canal nerve block catheters provides benefits for patients undergoing primary total knee arthroplasty. Methods: Patients aged 18 or older with an ASA score of 1-3 undergoing single primary total knee replacement were deemed eligible. After TKA procedure, adductor canal catheters were placed in the post-anesthesia care unit. Patients were followed for five consecutive days postoperatively. Inpatient data were obtained from the electronic medical record. After discharge, data were collected from daily phone calls. The main parameters were the average numeric pain score (0-10) at rest, the average numeric pain score (0-10) during and after physical therapy, and daily opioid consumption. Results: A total of 797 patients consented to take part in the study, 336 were lost to follow up, and 461 patients were included in the study. Among those with adductor canal catheters in place the average pain scores both at rest and during physical therapy decreased on Day 2 and Day 3. The average pain levels during physical therapy were significantly lower (p < 0.05) in patients with the catheter in place compared to those without, and opioid consumption was also decreased on these days. Conclusions: This study demonstrates that the prolonged use of adductor canal nerve block catheters may reduce pain and opioid consumption in patients undergoing primary TKA for up to 72 h postoperatively.