DESIGN: In this 2 × 2 factorial randomized controlled trial, 206 adults (mean age 66 years) who met the American College of Rheumatology criteria for hip or knee OA were randomly allocated to receive manual physiotherapy (n = 54), multi-modal exercise physiotherapy (n = 51), combined exercise and manual physiotherapy (n = 50), or no trial physiotherapy (n = 51). The primary outcome was change in the Western Ontario and McMaster osteoarthritis index (WOMAC) after 1 year. Secondary outcomes included physical performance tests. Outcome assessors were blinded to group allocation.