This study aims to provide high quality evidence from a double-blinded, randomized controlled trial on the efficacy of perioperative pregabalin in reducing morphine requirements, improving pain scores and reducing chronic neuropathic pain when compared with placebo for primary total knee arthroplasty. It hence aims to improve on choice of analgesia adjuncts for total knee arthroplasty.

Aims:

Whether pregabalin given preoperatively and for one week postoperatively in addition to patient-controlled analgesia (PCA) morphine is effective in reducing morphine requirements, improving pain scores and reducing chronic neuropathic pain when compared with placebo for primary total knee arthroplasty.

Methodology:

A single-centre double-blind randomized controlled trial in patients undergoing primary total knee arthroplasty. All subjects receive PCA morphine, paracetamol 1g every six hours, etoricoxib 120mg once daily postoperatively. Subjects receive either pregabalin 75mg po preoperatively followed by 75mg OM and 25mg ON for two days postoperatively or matching placebo. The primary outcome is cumulative morphine consumption at 72 hr following surgery. Secondary outcome measures included pain scores, knee range of motion and patient satisfaction.

Inclusion Criteria:

• patients undergoing primary total knee arthroplasty

Exclusion Criteria:

• revision or bilateral arthroplasty, significant renal or hepatic impairment, documented allergy or intolerance to NSAIDs, paracetamol, morphine or pregabalin, chronic pain syndrome treated with chronic opioids, obstructive sleep apnea not treated with continuous positive airway pressure, seizures, breastfeeding, inability to use patient-controlled analgesia.