The scenario that has been mentioned by you is very easy to happen.
Scaphoid fracture is a very easily missed fracture,because it is not very obvious on
x ray. It requires very careful scrutiny.So,that's why the orthopedic surgeon in your case picked up something, that was missed by the
radiologist.There is a very high chance that the orthopeadic surgeon was right in your case, and hence its advisable for you to follow his orders.