Bummer to hear about your ankle.
How is the healing/recovery progressing?

The synovium is a lining of the protective sheath that covers tendons. Tenosynovitis is inflammation of this sheath. 
What are you doing to reduce inflammation?
Are you using a splint or removable brace to keep the tendon(s) still?
Surgery to remove the inflammation around the tendon may be used in some cases. I don’t believe it is a  first option.

Did you have a cut or infection in the area?
If so, antibiotics are needed.
Are you seeing any  improvements with what you have been doing?