52 WEEK, INTERNATIONAL, MULTI-CENTER, RANDOMIZED, DOUBLE-BLIND, DOUBLE-DUMMY, PARALLEL-GROUP CLINICAL TRIAL TO COMPARE RETENTION ON TREATMENT, SAFETY, TOLERABILITY & EFFICACY OF LUMIRACOXIB 100 MG OD, LUMIRACOXIB 100 MG BID & CELECOXIB 200 MG OD IN PTS WITH PRIMARY OA OF HIP, KNEE, HAND OR SPINE: