St. James Hospital / Services & Specialties / Orthopaedics and Physical Performance / Sports Medicine / Services / Injection Therapy Injection Therapy Cortisone (Corticosteroid) Injections: Corticosteroids are not pain relievers—they reduce inflammation, often working within minutes. Once the inflammation is gone, the pain usually disappears as well. You can receive an injection in the doctor’s office, and one injection may be effective for months or even longer. Trigger Point Injections: Knots of muscle that cause pain are called trigger points. These can be treated with direct injections of an anesthetic called lidocaine, which works by breaking up the tight band of muscle. Hyaluronan Injections (Viscosupplementation): If you are diagnosed with mild to moderate knee osteoarthritis, this injection may be helpful to you. Hyaluronan is a natural substance that is in the joint fluid in a normal knee. Your doctor will inject hyaluronan several times over the course of weeks, and you will begin to feel the greatest relief from pain several weeks after the first injection.