<prompt> Joint LEAST involved in primary osteoahritis: March 2013 b, hHipTrapezio-metacarpalKneeCoraco-clavicular  <response>: Ans. D i.e. Coracoclavicular Osteoahritis Usually OA involves: - Hip, - Knee Does not affect MCP joint Interphalangeal joints nodes: - DIP - Heberdens node; PIP - Bouchard nodes X-ray shows: Osteophyte formation, narrowing of joint space etc. 