Can a cortisone injection to the knee cause swelling?

Yes, a cortisone injection to the knee can cause temporary swelling as a side effect. This swelling may occur due to the body's reaction to the injection or from the cortisone itself, which can lead to fluid retention in the joint. Typically, this swelling is short-lived and may subside within a few days. If swelling persists or worsens, it’s advisable to consult a healthcare professional.