Research has shown that corticosteroids injected into the joint work for reducing knee pain caused by osteoarthritis. But how long does the effect last? Osteoarthritis is a chronic problem, so long-term solutions are needed. Just how well do steroid injections work? According to the results of this study: the pain reducing effect lasts about one week. Steroid injections offer short-term pain relief but they aren't advised for more than that.

Since we know that almost half of all adults age 80 and older will have osteoarthritis of the knee, finding ways to decrease the painful symptoms is important if these folks are going to stay active and independent. Not only that, but almost one-quarter of the entire U.S. adult population have some symptoms of arthritis. That's a staggering statistic and a significant one given the focus on physical activity and exercise as the best way to stay healthy, avoid weight gain, and manage diseases like osteoarthritis as well as diabetes and high blood pressure.

The authors did an extensive electronic review of the published articles on the subject of corticosteroids for joint osteoarthritis. They were specifically looking for data that would show if corticosteroid injections work for this problem. And if so, how well do they work, and how long does the effect last? While they were compiling the data, they also decided to take a look at the various steroids used (e.g., betamethasone, methylprednisolone, triamcinolone) and see if one was better than the rest.

There weren't very many studies: only six trials reported in five different papers compared a corticosteroid to a placebo. And only four separate studies compared results using different types of corticosteroids. This type of review is called a systematic review. It is a good way to look at the evidence supporting or refuting any kind of treatment, including steroid joint injection. Individual doctors, clinicians, and even patients (consumers) just don't have the time to comb through all the literature looking for answers. Or in the case of consumers, they may not really know how to analyze and interpret what they read. Systematic reviews like this one do the leg work for us.

So, here's what they found out. Besides showing that knee pain was reduced for at least one week, there was also evidence that the pain was decreased by 30 per cent. Triamcinolone came out as the front-runner in providing the best results. But not all corticosteroids were included in comparative studies and the use of validated outcome measurements was very limited. Outcome measures refers to the way results are measured such as the visual analog scale (VAS) as a clinical indication of pain and change in pain. Other validated tests that could be used also include the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Short-form-36 (SF-36).

For those who are interested, the authors do provide some details about the studies included in this systematic review. A discussion of research methods, results, weaknesses of the studies, and tables to show how they were compared are provided. Each study design such as single-blind, double-blind, crossover was listed along with the type of corticosteroid used, dosage, and similar information regarding the placebo used.

It's always helpful when doing comparative studies to also compare patient demographics. Demographics refer to patient characteristics such as age, sex, education level, socioeconomic status, and type of diagnosis. For this study, an additional measure (duration of disease) was also included. Results were primarily measured in terms of pain relief and patients were followed anywhere from one to 24 weeks (six months). The idea that corticosteroid injections provide only short-term pain relief at best is supported by other studies. When a longer period of time for pain relief was reported, the differences between steroid group and placebo group were not considered significant.

Other studies have investigated whether or not physicians can really deliver the injection into the joint space. The overall conclusion of studies looking at this factor is that properly trained medical staff can deliver the medication into the knee joint with no problem at all. Other joints such as the hip or shoulder may be more problematic requiring the use of fluoroscopy, a special real-time (3-D) X-ray that allows the surgeon to see what her or she is doing.

Fortunately, even though steroids only give short-term pain relief, there are other effective treatments patients can use as well. Physical activity and exercise, nutritional supplements, antiinflammatory drugs, braces, topical creams, and if necessary, surgery are all acceptable treatment choices. Finding the most optimal single treatment or combination of treatments may be an individual decision. More research is clearly needed in comparing different steroid injections, the timing and dosage of the injections, and factors that predict which patients are most likely to respond.

Reference:
C. Tate Hepper, MD, et al. The Efficacy and Duration of Intra-articular and Steroid Injection for Knee Osteoarthritis: A Systematic Review of Level I Studies. In Journal of the American Academy of Orthopedic Surgeons. October 2009. Vol. 17. No. 10. Pp. 638-646.