What are the complications of having both ankle joints debrided 2 years post trimaleolar fracture repair?

Ask your doctor. All surgeries can have complications such as scaring, infections, nerve injuries, blood vessel injury, clot in the legs which can be fatal, persistence of pain, progression of arthritis, need for additional surgeries, anesthesia complications etc. In your case, my concern would be persistence of your pain which required joint debridement possibly from developing arthritis. Check with surgeon.
Non relief of pain. Why are u having debridement? Hardware removal may be helpful if the screws cause irritation. Cleaning out the joint (commonly with a scope) may take care of some mechanical symptoms but the arthritis will still be there and cause some residual pain and likely will get worse over time.