Damaged lymphatic system after tummy tuck, 3 years post op.

Thank you for your question. The lymphatics for the legs are not in the operative field, so the LN were not damaged during the TT. You stated that the thighs "seem swollen"; this could very well just be that you are noticing them more now that your abdomen is flatter. Have you gained weight? Some people have preferred spots for storing excess weight and yours may be your legs. There are multiple causes for lower extremity swelling, but the TT itself is not high on the list.  

The surgery is carried out above the lymph nodes that drain your lower extremities so it is very unlikely the tummy tuck contributed to the situation since it leaves that drainage system intact. It is possible that there are are other issues that need to be evaluated such as lipidema, lymphedema, and so forth. I would see a board certified plastic surgeon and an internist and be evaluated, especially if the swelling includes your ankles and feet.