Corticosteroid/Ropivacaine Versus Corticosteroid/Saline Injections for Knee Osteoarthritis

Does Anesthetic Contribute to Symptomatic Relief in Corticosteroid Injections for Knee Osteoarthritis? A Double-Blind Randomized Trial Comparing Corticosteroid/Ropivacaine Versus Corticosteroid/Saline Injections

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.

The KOOS holds 42 items in five separately scored subscales: Pain, other Symptoms, Function in daily living (ADL), Function in Sport and Recreation (Sport/Rec), and knee-related Quality of Life (QOL). A Likert scale is used and all items have five possible answer options scored from 0 (No Problems) to 4 (Extreme Problems) and each of the five scores is calculated as the sum of the items included. Scores are transformed to a 0-100 scale, with zero representing extreme knee problems and 100 representing no knee problems.

Pain was measured by a Visual Analog Scale (VAS) marked from 0 (no pain) to 10 (unbearable pain) at rest and with activity. It was collected at baseline (pre-injection), immediately post-injection on the day of surgery, and at 2 weeks and 3 months.

The Tegner activity level scale is a scale that aims to provide a standardized method of grading work and sporting activities. The Tegner activity level scale is a graduated list of activities of daily living, recreation, and competitive sports. The patient is asked to select the level of participation that best describes their current level of activity and that before injury. A score of 0 represents sick leave or disability pension because of knee problems, whereas a score of 10 corresponds to participation in national and international elite competitive sports. A score >6 can only be achieved if the person participates in recreational or competitive sport.

Inclusion criteria: Age 18 or older Knee osteoarthritis (uni- or bilateral) as defined by the American College of Rheumatology (staged by Kellgren-Lawrence radiographic grading scale) Exclusion criteria: Rheumatologic/inflammatory disease Metabolic bone disease Crystalline arthropathy Current smoking BMI > 40 Knee injection with corticosteroid or viscosupplementation within previous 6 months History of knee prolotherapy, platelet rich plasma or cellular (stem cell) injection Knee surgery within the last year Chronic opioid use Chronic pain syndrome/fibromyalgia Pain behavior during the clinical encounter as judged by the injecting physician Physician specifically ordered injection of corticosteroid/anesthetic or other specific combined corticosteroid injection Diagnostic uncertainty by referring provider Referral for bilateral knee or multiple joint injections (*note that arthritis involving multiple joints alone is not an exclusion criteria, only the patient receiving more than 1 injection)