Efficacy Study of Pre-emptive Etoricoxib for Postoperative Pain and Functional Outcome in Total Knee Arthroplasty

Inclusion Criteria: * Patients between the ages of 50 and 80 who are listed for single-knee TKA at Singapore General Hospital by one of 4 adult reconstructive surgeons for the treatment of osteoarthritis will be recruited upon the patient giving written informed consent. Exclusion Criteria: * \- Younger than 50, older than 80 * Known allergy to etoricoxib or other cycloxygenase-2 inhibitors, aspirin or any Non-steroidal Anti-inflammatory Drugs (NSAIDs) * American Society of Anaesthesiologists (ASA) grade IV * Renal insufficiency (Creatinine \> 110) * Known coagulation or hepatic disorder * Inflammatory arthritis * Inflammatory bowel disease * Concurrent conditions which would affect interpretation of pain eg spinal stenosis, lumbar nerve root impingement * Depression or usage of opioids, sedatives or hypnotics preoperatively * Special classes of subjects including those pregnant, cognitively impaired, prisoners or institutionalized patients * Patients with clinically significant abnormalities of laboratory safety tests at baseline, or a history of significant clinical or laboratory abnormality that in the opinion of the investigator would contraindicate the use of etoricoxib * Patients with unstable hypertension, uncontrolled diabetes mellitus, New York Heart Association (NYHA) class II-IV congestive heart failure, ischaemic heart disease, cerebrovascular disease or peripheral vascular disease (including patients who have recently undergone coronary artery bypass graft of angioplasty) * Patients with active gastric ulceration or gastrointestinal bleeding * Patients with a history of any illness that in the opinion of the investigator may confound the results of the study or pose additional risks to the patient * Occurrence of any surgical complication would exclude the patient from analysis