40 years patient having arthritis of PIP and DIP along with a carpometacarpal joint of the thumb and sparing of the wrist and metacarpophalangeal joint, most likely diagnosis is -
Involvement of PIP, DIP and 1st Carpometacarpal joint (Carpometacarpal joint of thumb) with sparing of the wrist and the metacarpophalangeal joint is characteristic of OA.