Abstract and Introduction
Abstract
Objective: Although some disagreement exists amongst practitioners as to the efficacy of corticosteroid injection into the osteoarthritic knee, this procedure remains the most common reason to perform knee joint injection. There is disagreement too over the most efficacious corticosteroid for the procedure; the dose required at injection; the frequency, and total quantity of corticosteroid that can be injected into the knee. This paper examines the controversies surrounding the efficacy of corticosteroid injection into the osteoarthritic knee, and attempts to provide guidance as to appropriate corticosteroid selection, dose, and treatment interval.
|Method: Searches were made of electronic databases, and appropriate papers were identified and hand-searched.
Results and Conclusion: Although numerous investigations have been conducted in an attempt to identify the optimal corticosteroid agent, and its optimal dosing regimen for the intra-articular treatment of osteoarthritis, a consensus has not been established. The current recommendations for dosing interval appear to have arisen as a consequence of a misinterpretation of previously published works. This paper recommends that practitioners refine and individually tailor their selection of agent and dosing regimen to patient needs and clinical response.
Introduction
There are two ways to inject (or aspirate) the knee – my way and the wrong way.
(Traditional)
The knee is the largest synovial joint in the body. It is subject to a wide variety of insults which may necessitate aspiration and/or injection of the joint. Aspiration of the knee joint may be performed for the diagnosis of an unexplained effusion, or the evacuation of a painful one. Injection of the knee can be undertaken for radiological investigation of the knee, for the injection of corticosteroid into a joint suffering from a non-infectious inflammatory process, or for the injection of viscosupplementation. Of these indications for aspiration or injection of the knee joint, the most common is the injection of corticosteroid in cases of osteoarthritis (OA) of the knee.
In Australia, musculoskeletal (MSK) conditions (which includes the various arthritides) are the third leading reason (equal to that for 'cardiovascular problems') for a visit to a General Practitioner (GP) (17%), following 'respiratory problems' (22%), and 'unspecified general problems' (19%). Interestingly, the proportion of MSK presentations that are due to OA is unknown. Similarly, there is no data available regarding the breakdown of clinical presentations to Sport Doctors or Sport Physicians.
Osteoarthritis is the most common musculoskeletal (MSK) condition affecting Australians, with a reported prevalence of 15% of the population, or just under 3 million people (in 2000). Peat et al. reported that 10% of patients aged 55 or more in the UK and Netherlands experience painful, disabling OA of the knee, and a quarter are severely disabled. A recent American report found that symptomatic knee OA occurs in 10% of men and 13% of women aged 60 years or older. It has been estimated that the incidence, or number of new cases/year in Australia, is some 27,000 new cases of radiological OA for women, and approximately 15,500 new cases for men. Guillemin et al. determined that knee OA prevalence in French men and women ranged from 2.1%–10.1% and 1.6%–14.9% respectively, and varied by geographical region. In a Chinese cohort, Hunter et al. reported the prevalence of radiographic tibiofemoral OA to be 21.9% in men and 41.8% in women, and the prevalence of radiographic patellofemoral OA to be 25.9% in men and 35.7% in women. Symptomatic knee OA was determined to be present in 9.7% of men and 20.3% of women. Tveit et al. reported that knee OA is more commonly found in male former elite athletes, and that knee OA is associated with a previous knee injury in former impact athletes, but not in non-impact athletes.
The initial recommended treatments for OA are the various non-pharmacological modalities (patient education, various self-management programmes, diet, and other therapies) and pharmacological therapies (involving non-opiate oral analgesics as well as the application of topical agents). The use of intra-articular (IA) corticosteroid can be considered in patients that are unresponsive to these treatments, and is recommended when signs of local inflammation with joint effusion are present. The first reported use of IA corticosteroid in knee OA was by Hollander in 1953, and the first clinical trial of IA steroid use for knee OA was reported by Miller, White and Norton in 1958.
A major Cochrane review by Bellamy et al. evaluated the efficacy and safety of IA corticosteroids in the treatment of knee OA. The review determined that there was evidence of benefit for both pain and patient global assessment at one week post-injection, and that there was no evidence for effect on function (but data for this measure was sparse). There was evidence at 2–3 weeks post-injection that corticosteroid was more effective than placebo in the reduction of pain. From 4 to 24 weeks post-injection, there was no compelling evidence of benefit, although some mid- and late-stage benefit in favour of corticosteroid was noted. The authors concluded that it appears that the beneficial effects of IA corticosteroid are rapid in onset, but may be relatively short-lived (1–3 weeks). There was no evidence of long-term efficacy. It is unknown why there is inter-patient variability in response to the various IA corticosteroids available.
Despite there being numerous publications concerning the use of IA corticosteroids in the treatment of the symptoms of knee OA, there is little agreement as to the most efficacious agent, nor is there agreement on the dose and dosing regimen of these agents.
This paper aims to examine the selection of corticosteroid agent, the dosing regimen, and frequency of injection of corticosteroid agent into the osteoarthritic knee, and makes recommendations as to the safe and optimal usage of these medications.