Fractures of the scaphoid can be treated with splints, casts or surgery. For fractures at the thumb end of the scaphoid when the pain is not too bad, it might be possible to manage these in a splint.
For fractures of the waist small movements can impair bone healing, and so generally cast immobilisation is recommended. If there is a delay in bone healing, then an operation can be done to pass a screw across the scaphoid via a very small cut in the skin. These screws are designed to provide compression across the fracture, which allows the bone to heal.
For fractures of the forearm end of the scaphoid the blood supply is generally not good. There is very significant concern about healing in this region. Normally surgery is recommended, through an open approach, and often combined with the insertion of a bone graft to improve the healing rates. A screw is then passed over the bone graft.
For more info see:-
Scaphoid fractures – Rupert Wharton
References:-
Davis TRC Ann R Coll Surg Engl 2013; 95: 171–176 doi 10.1308/003588413X13511609956895