Great question and a problem I see all of the time. The skin just above the knee is perhaps the toughest skin in the world to get to tighten with either liposuction and/or Smartlipo. I am fairly good at getting skin to tighten in many areas all over the body using Smartlipo and a technique called "Superficial Technique" and even i find it very difficult if not impossible to see an improvement in this area with these techniques. There is a procedure called a "Body Lift" that might improve this area somewhat or an extended medial thigh lift, but both of these procedures are very aggressive and leave large scars on your body.
If one has significant loose skin above the knees (rolls), only an excision or so called knee lift will be effective. While effective the ultimate question is whether the resultant scar is a worthy trade-off. The interpretation of that scar is a personal one and is influenced by how bad one feels about the suprapatellar knee rolls. Looking at pictures of those scars makes that answer very clear.
This area can be treated with great results if you find an expert at body contouring and skin tightening. I suggest you post photos or see a body contouring specialist who does many of these procedures. Best, Dr. Emer