Adductor Canal Block After Total Knee Replacement - a Suture-method Catheter vs a Standard Catheter vs a Single Bolus

Comparison of the Analgesic Effect of an ACB (Adductor Canal Block) Using a New Suture-method Catheter vs a Standard Perineural Catheter vs a Single Bolus: A Randomized, Blinded, Controlled Study

In this study we wish to investigate the analgesic effect of the administration of 0.2% ropivacaine for an adductor canal block as repeated boluses (20 ml every 8 hours) through a new suture-method catheter or a standard perineural catheter compared with a single bolus (20 ml), in patients following primary total knee arthroplasty.

The aim of the study is to compare the clinical effects of three different administration forms for an ACB: repeated intermittent boluses through a Certa catheter (CC) versus repeated boluses through a standard catheter (through the needle) (SC) versus a single bolus (SB). Our dual hypothesis is that repeated boluses through a catheter (either Certa or standard catheter) reduces opioid consumption (primary outcome), as well as reduces pain scores, enhances ambulation and muscle strength compared with a single bolus, and that the Certa catheter is superior to a standard catheter.

Inclusion Criteria:

• Patients scheduled for unilateral total knee arthroplasty in spinal anesthesia
• Patients who gave their written informed consent to participating in the study after having fully understood the contents of the protocol and restrictions
• ASA 1-3
• Ability to perform a TUG test preoperatively

Exclusion Criteria:

• Patients who cannot cooperate
• Patients who cannot understand or speak Danish.
• Patients with allergy to the medicines used in the study
• Patients with a daily intake of strong opioids (morphine, oxycodone, ketobemidone, methadone, fentanyl) during the last 4 weeks
• Patients suffering from alcohol and/or drug abuse - based on the investigator's assessment
• Rheumatoid arthritis
• BMI > 40
• Neuromuscular pathology in the lower limbs
• Pregnancy