“What is the success rate of TMJ surgery?”

Depends on too many variables to say specifically. I recommend you see an Oral and Maxillofacial surgeon who is experienced with TMJ surgery for a better answer.

This isn't an easy question to answer because it depends on a lot of things. It's like asking how successful knee surgery is when there are a multitude of different types of surgery on both the knee and the TMJ. Anyone trying to answer this would be foolish if they didn't know exactly what you were having done, plus there's the variable of who is doing the surgery? I would get a professional opinion from an oral surgeon who does a fair amount of joint surgery about what the typical prognosis is, and maybe even get a third opinion before undergoing your surgery - it's irreversible and is always valuable to determine the risk/benefit ratio before making the decision. Lastly, make sure the person doing the surgery has done a lot of them because that's another variable if it's an unpredictable procedure.