When do you treat a Baker's cyst?

When it does not go away on its own, doctors treat a Baker's cyst by injecting the knee with a corticosteroid medication, draining the fluid and using physical therapy. Surgery may be necessary to treat a cartilage tear causing the cyst, notes Mayo Clinic.

The injection of cortisone into the knee reduces inflammation, but it may not keep the cyst from returning. To drain fluid from the knee, the doctor performs a needle aspiration while using ultrasound to guide the needle. Physical therapy may involve icing the knee and using crutches or a compression wrap. Gentle exercises and stretches can improve the knee's range of motion and alleviate symptoms caused by the cyst, according to Mayo Clinic.