If I Get a Cortizone Shot in Knee 2 Weeks After Coolsculpting, Will It Stop Results?

The localized effect of the corticosteroid injection in the knee probably won't negatively interact in the beneficial effect of CoolSculpting for fat loss done elsewhere on the body.

The information provided in Dr. Shelton's answer is for educational purposes only and is not intended to constitute medical advice.  The information provided should not be relied upon as a substitute for consultations with a qualified health professional who may be familiar with your individual medical needs.

Thank you for your question. No, a cortisone shot in the knee two weeks after CoolSculpting will not stop results.

Your cortisone injection will not affect your CoolSculpting result.  CoolSculpting works by injuring fat cells with cold.  This injury causes fat cells to commit suicide (undergo apoptosis).  Your body has a method of clearing up these apoptotic cells, which is what happens during the 8 weeks after your treatment.  

Also, by the way, your cortisone injection will act locally (on your knee).  Full-body side effects from knee injections would be unusual.