Corticosteroid/Ropivacaine Versus Corticosteroid/Saline Injections for Knee Osteoarthritis

Corticosteroid injections are commonly used for the symptomatic treatment of knee osteoarthritis. Common practice is to inject the joint with a combination of corticosteroid and local anesthetic, with the rationale of providing longer duration pain relief with the corticosteroid and immediate, though short duration relief with the anesthetic. However, multiple in vitro and animal studies have shown that local anesthetic may be harmful to chondrocytes. Despite this data, use of intra-articular anesthetic remains widespread. Many clinicians believe incorporating the anesthetic is important because it can provide immediate pain relief and facilitate patient confidence in the treatment program. However, there is no published data to validate this reasoning. Therefore, the anesthetic has unknown clinical benefit and may have adverse effects on articular cartilage. In light of this, the investigators question the routine use of anesthetics in joint injections. The purpose of this study is to compare the effects of knee joint injections using: 1) corticosteroid with local anesthetic versus 2) corticosteroid with normal saline.