Probably a visit to an orthopaedic specialist would answer your questions. It is hard to say how to solve the problem without knowing the cause of it.
I have one leg that
seems about 1/2 inch longer than the other. Actually, my pelvis is not symetrical, so the
affect is one leg longer than the other. But when I wear slacks or a skirt with a belt, you can see the slope at the waistline and notice that is where the discrepancy is. I never really knew it until I went to a sports medicine specialist and he measured and xrayed me. The funny thing is, I always wondered why sometimes I was 5'2" tall, and sometimes 5'3" tall. The reason? Because at the times my height was measured, sometimes I put my weight on the left foot, sometimes on the right foot. Depending on whether or not I was standing on the "long" leg or the "short" leg, my height measured differently.
Going to the doctor finally solved my question of why all my skirt hems always looked crooked.

Now I know that I need to sew a sloping hem on the skirt, and then it looks straight when I wear it.
Orthonic "lifts" do help some conditions.
Where on your leg is your "dent"? Is it in the muscle tissue, or at a joint?
If it doesn't bother you too much, then special inserts for your shoes might be a less drastic option than surgery.
Going to a doctor is probably the best idea because as our bodies age little problems sometimes become bigger problems.
