The Analgesic Efficacy of Local Anaesthetic Wound Infiltration Versus Intrathecal Morphine for Total Knee Replacement

A Comparison of the Analgesic Efficacy of Local Anaesthetic Wound Infiltration Versus Intrathecal Morphine for Total Knee Replacement

Total knee replacement (TKR) is associated postoperatively with considerable pain and analgesic requirement. Total knee replacement is routinely performed under spinal anaesthesia with intrathecal bupivacaine plus preservative free morphine. We hypothesize that infiltration of the surgical site with peri- and intraarticular levobupivacaine local anaesthetic would be an efficacious pain management technique and would not be inferior to intrathecal morphine for postoperative pain management.

We further hypothesize that the use of this surgical site infiltration technique would decrease post-operative systemic opioid requirements as well as the side effects associated with intrathecal and systemic opioids.

Inclusion Criteria:

• Patients scheduled for unilateral total knee replacement
• Consent to spinal anaesthesia
• ASA Grade I to III

Exclusion Criteria:

• Patient refusal
• Mini-Mental Score < 25 (see appendix 3)
• Allergy to bupivacaine, morphine, paracetamol, diclofenac
• Skin lesions/infection at site of injection
• Uncorrected renal dysfunction
• Coagulation disorders
• chronic pain condition other than knee pain