Least common site to be involved in osteoahritis amongst the following is:
Answer is D (Metacarphalangeal joints) Wrists and Metacarpophalangeal joints are generally not involved in Osteoahritis - Harrison 16th/2040 Sparing of wrist and metacarpophalangeal joint with involvement of base of thumb (i.e. carpometacarpal joint) is very characteristic of 'osteoahritis'.
Hip joint
Knee joint
Carpometacarpal joint of thumb
Metacarpophalangeal joint