This treatment helps to return some of the normal occurring chemicals back to the joint that are diminished in patients with arthritis. These can range from a single injection to a series of three injections. Insurance only approves these for diagnosis of knee arthritis. Other areas, such as shoulder, hip and elbow, are not approved. Results are variable but can last for up to 6 months and usually depend on the degree of arthritis. While a variety of injection brands are available, this choice is often dictated by your insurance.