Could tendonitis in the wrist be caused by having broken a bone?

Yes: Tendonitis can either be associated with an underlying break or symptoms of what is presumed to be tendonitis may actually be those of a un-recognized fracture. Likewise for ligament sprains. So if there are unresolved symptoms a plain x-ray, at the very least, is called for.

Tendonitis fracture: Tendoniitis can come fom a prominent bone or a boney spike or an irregular bone n the floor of a tendon sheath, however it is uncommon . If youi are not sure you have a bone and have symptoms of tendonitis and the tenodonitis is a mystery, an occult or hidden fracute may be responsible. A common bone that may give pain with negative xray is the scaphoid, add. Exam, mri, bone scan and hand surgeon.