Hello and thank you for your question. CoolSculpting is FDA-approved for use in a variety of areas, including the upper arms, back, thighs, abdomen, flanks and more. It is not currently FDA-approved for treating the area behind the knees, although it may not necessarily be dangerous to do so. An experienced and qualified CoolSculpting provider may be able to go off-label and use the applicator to treat your specific area of concern. Before moving forward with any CoolSculpting treatments, make sure your physician is CoolSculpting certified. If you have any other questions about the CoolSculpting process, discuss them with your care provider during your in-person consultation. Hope this helps!