Thank you for your question. I recommend a combination of procedures for optimal results.
ThermiTight utilizes a small electrode inserted under the skin to heat tissue to a selected therapeutic temperature. Literature has shown that elevating skin to a therapeutic temperature level can contract collagen molecules and stimulate collagen production, which may give the appearance of lifting or tightening. Fat reduction is rare, unless set to high temperatures and kept at high temperatures for a significant amount of time .
To best answer your question, it depends on how much skin laxity you have. ThermiTight can work well in the thigh area to tighten skin that is mild to moderately laxity. Surgery may be a better option, if you have excessive laxity. Results with ThermiTight vary from patient to patient. You should experience some overall improvement.
The best way to assess and give true advice would be an in-person exam.
Please see a board-certified plastic surgeon that specializes in aesthetic and restorative plastic surgery.
Best of luck!
Board Certified Plastic Surgeon