Efficacy of Celecoxib 200mg in Relieving Pain and Walking Dysfunction in Osteoarthritis of the Knee

Inclusion Criteria: * If female and of childbearing potential, must be using adequate contraception since last menses and will use adequate contraception during the study, * Diagnosed as having OA of the knee * Functional Capacity Classification of I-II (FCC) * If on active analgesic or anti-inflammatory pain medication, must have VAS pain score\>=30mm in signal knee related to walking on a flat surface within the previous 48 hours. Subjects who are not taking any pain medication must have a VAS pain score\>=40mm in the signal knee * At baseline visit, must have a history of pain in the signal knee\>=40mm when walking on the flat within the previous 48 hours. * In the Investigator's opinion, the patient requires and is eligible for therapy with an anti-inflammatory analgesic. * If on an NSAID or analgesic, patient must have completed a washout period prior to baseline assessments that is a minium of five half lives. * The patient has provided written informed consent before undergoing any study procedures. Exclusion Criteria: * Diagnosed as having inflammatory arthritis or acute trauma at the index joint. * Another painful condition that would interfere with his/her ability to walk or to make reasonable assessments of their pain. * Received an injection of corticosteroid into the signal knee within 3 months; or with a hyaluronan produce in the signal knee within the previous 6 months. * Requires the use of a cane or other assistive device to complete the walk. * Known cardiovascular disease which has been symptomatic in the past 12 months * History of blood clots or is at any increased risk for blood clotting. * Asthma or any breathing condition which would preclude walking briskly for 20 consecutive minutes or 40 minutes total. * Has taken any NSAIDs, COX-2 inhibitors, or any analgesic, with the exception of the rescue acetaminophen, within two days prior to Visit 2 * Active malignancies or any type or a malignancy that has recurred within 5 years before enrollment. * Diagnosed as having or has been treated for esophageal, gastric, pyloric channel, duodenal ulceration within 90 days * Active GI disease, a chronic or acute renal or hepatic disorder, or a significant coagulation defect. * Any chronic illness or laboratory abnormalities considered to be clinically significant. * Received any investigational medication within 30 days * Known hypersensitivity to celecoxib, NSAIDs, to sulfonamides * Use of the following drugs: 1. NSAIDs or COX-2 specific inhibitors 2. Analgesics except rescue medication within 24 hours of a study visit 3. Anticoagulants 4. Lithium 5. Glucosamine or chondroitin sulfate are excluded unless on stable dose for at least 3 months