How is tenosynovitis in the flexor hallucis longus tendon sheath treated if it is not infected?

Overuse and chronic?: If its an overuse injury--running too much perhaps--then rest is of primary importance. This is normally the case so I'll assume this is what's happening with you. The more you can NOT flex down your big toe the better. That means no flip-flops and wearing stiff soled shoes as much as possible. If it becomes more and more bothersome so its difficult to walk normally see your doctor