Adductor canal catheters provide better pain control on postoperative day 1 prior to, during, and after patients’ first physical therapy session following total knee arthroplasty (TKA), compared with intra-articular catheters, according to a study presented here at the ANESTHESIOLOGY 2015, the Annual Meeting of the American Society of Anesthesiologists (ASA).

Furthermore, adductor canal catheters significantly reduced oxycodone consumption at 24 and 48 hours, compared with intra-articular catheters.

TKA is associated with severe postoperative pain, and multimodal analgesia, including peripheral nerve blocks, is recommended for relief of this pain. Adductor canal blockade has been shown to reduce opioid consumption in the first 48 hours after TKA while decreasing incidence of quadriceps weakness that is seen in femoral nerve blockade.

The advantage of perineural catheters is that they can extend pain relief for up to 48 hours after surgery. Intra-articular catheters are becoming increasingly popular and have proven to be effective in patients undergoing TKA compared with IV or intrathecal opioids while also preserving quadriceps strength. However, to date, there have been no randomized controlled trials comparing the efficacy of adductor canal catheters to intra-articular catheters in patients undergoing TKA.

For the current study, Marc W. Kaufmann, DO, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, and colleagues randomised 66 patients undergoing primary TKA to receive either an intraoperative intra-articular catheter or a postoperative adductor canal catheter.

The intra-articular catheter group received a constant infusion of 0.5% bupivacaine at 4 ml/hr while the adductor canal catheter group received 0.2% ropivacaine at 10 ml/hr. The groups were statistically similar in age, body mass index, sedation used, and time spent in the post-anaesthesia care unit.

According to a numeric scale (0-10) elicited during the patients’ first goniometric assessment on postoperative day 1, patients in the adductor canal catheter group experienced significantly less pain prior to, during, and after manipulation than those in the intra-articular catheter group.

Furthermore, oxycodone consumption at both 24 and 48 hours was significantly reduced in the adductor canal catheter group compared with the intra-articular catheter group. There was no difference between the groups in terms of the effects of opioid tolerance on pain scores or oxycodone consumption.

Dr. Kaufmann noted that the study is still going. “We have 15 more patients to include in the data set and will be looking at long term follow ups at 6 to 8 weeks post-op,” he said.

[Presentation title: A Randomized Controlled Trial Comparing the Adductor Canal Catheter (ACC) and Intra-Articular Catheter (IAC) Following Primary Total Knee Arthroplasty. Abstract A1298]