A patient on colles cast present after two weeks with the inability to extend his thumb, the most likely reason is:

Ans: A (Rupture of extensor pollicis longus tendon) Ref: Apleys System of Orthopaedics and Fractures, 9th edition, p 774Explanation:Rupture of extensor pollicis longus occasionally occurs a few- weeks after an apparently trivial undisplaced fracture of the lower radius.The patient should be warned of the possibility and told that operative treatment is available.