Adductor Canal Block With Continuous Infusion Versus Intermittent Boluses and Morphine Consumption

Adductor Canal Block With Continuous Infusion Versus Intermittent Boluses and Morphine Consumption: A Randomized, Triple-masked, Controlled Study

The investigators believe sufficient spread to all nerves within the adductor canal-and thereby sufficient analgesia-can only be obtained by bolus injections and not by continuous infusions via a catheter. The aim of the study is to investigate whether an adductor canal block performed as repeated intermittent boluses provides superior pain relief to continuous infusion. The investigators hypothesize that adductor canal block performed as intermittent boluses via a catheter will reduce morphine consumption and pain as well as enhance ambulation and muscle strength compared with continuous infusion.

Inclusion Criteria:

• Patients scheduled for 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
• American society of anesthesiologists 1-3
• Ability to perform a timed up and go 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