Mike: Hello, I'm Mike Clarke, podcast editor for the Cochrane Library. Osteoarthritis is the commonest type of arthritis and there are Cochrane reviews for many interventions that might be used to treat it. These were added to in October 2022 with a new review of the effects of using adjunctive therapies along with land-based exercise therapy for osteoarthritis of the hip or knee. In this podcast, I'm pleased to speak with lead author Helen French from the Royal College of Surgeons in Ireland, about the importance of the review and its findings.

Mike: Hello Helen, perhaps you could begin by telling us a little more about osteoarthritis.

Helen: Hello Mike. Osteoarthritis is a type of arthritis, which is often described as a degenerative arthritis, as opposed to an inflammatory arthritis, such as Rheumatoid Arthritis. It's the most common type of arthritis and one in ten of the world's population aged over 60 years has the condition. It most commonly affects the knee, hip and hand joints, but can also affect other joints in the body. The most significant symptom is pain, which can affect everyday function and activities, such as walking, going up and down stairs, participating in hobbies, physical activity, sports, work and everyday life generally. The pain can also be present at night, affecting sleep. All in all, osteoarthritis can negatively affect an individual's quality of life and their ability to live their best life.

Mike: It's clearly important to find effective therapies for it, and you've looked at ones called adjunctive therapies in your Cochrane review. What are they?

Helen: Adjunctive therapies are therapies that are used alongside core or first-line treatments such as exercise therapy and education. They include things such as manual (or hands-on therapy), psychological therapies, acupuncture, dietary interventions for weight management, and the use of heat or cold therapy. They can also include drug therapies and supplements, such as glucosamine, but we didn't include those in this review.

Mike: Moving on to the review, why was it important to do it?

Helen: We know from previous Cochrane reviews that exercise for knee or hip osteoarthritis reduces pain and increases physical function, and it's widely recommended as a core or first-line treatment for osteoarthritis. There have also been numerous Cochrane reviews of the adjunctive therapies we're interested in, such as heat, cold, TENS, ultrasound; but as stand-alone therapies, and, in reality, they are rarely given on their own. Instead, they might be used in conjunction with a first-line treatment, such as exercise therapy, and, so, we wanted to focus on the added benefits when these therapies are used alongside land-based exercise therapy when used for hip or knee OA (ie exercise on land rather than in water).

Mike: How much research did you find and did it contain the evidence you needed?

Helen: There was a lot of research out there. We identified 62 trials with just over 6500 participants across 24 countries. One of these included people with either hip or knee osteoarthritis, one included only people with hip osteoarthritis, and the other 60 trials were limited to people with knee osteoarthritis. Nearly all the studies focussed on outcomes such as pain and physical function and most measured these outcomes just after treatment finished or over the next six months. Few measured how participants were doing 6 or 12 months later, which is important to know for a chronic disease such as osteoarthritis.

Mike: How good was the research?

Helen: Quality varied a lot across the trials, which affects the certainty of the evidence, in particular in relation to blinding of patients and providers. For some therapies, such as laser or ultrasound, the machine can be switched on but deactivated so that the patient doesn't know that they are not getting an active dose but, in general, blinding patients and treatment providers so that they don't know what a patient is receiving can be very difficult, compared with drug trials where you can give a patient a dummy or placebo drug. For example, if the treatment provider is an inherent part of treatment delivery, such as with psychological interventions or manual therapy, it's very difficult to blind both them and the patient. This meant that only 22 of the trials had a placebo adjunctive therapy. There were also some other elements of trial design, such as the randomisation, that were either poorly done or not explained well in the trial reports.

Mike: Moving on to the findings of the review, what would you say are the most important?

Helen: Starting with the placebo-controlled trials, when we compared adjunctive therapies with exercise against the placebo adjunctive therapy with the identical exercise, we found that the differences for pain and physical function were not clinically meaningful in the six months after treatment and very few of these studies measured other outcomes such as quality of life.
When we compared the adjunctive therapies with exercise against exercise only, we also found that any differences in pain or physical function were not clinically meaningful. However, five studies did show that overall improvement in their condition as rated by the patients was significantly higher with adjunctive therapy.

Mike: What about safety? Did you find any evidence on complications and adverse events?

Helen: Only 8 of the 62 trials measured adverse (unwanted harmful) events. The most common were increased pain, stiffness or swelling and the number of adverse events when using additional therapies with exercise was similar to when using sham therapies with exercise. However, it was generally unclear if a reported adverse event was due to the exercise therapy or the adjunctive therapy or, even if it was directly related to treatment.

Mike: Overall, then, what are your take-home messages for practice and for research?

Helen: When we look across all the therapies in the 62 trials that we included, using adjunctive therapies alongside land-based exercise therapy for hip or knee osteoarthritis produced no added improvement in pain, physical function or quality of life compared to exercise alone in the six months after treatment. However, there may be a slight clinical benefit for adjunctive therapies plus exercise compared with exercise when it comes to patient-reported global assessment, but this was based on a small number of studies. For research, it would be good to see longer term follow-up because most studies to date have evaluated short-term effects only, with little evaluation beyond six months.

Mike: Thanks Helen. Finally, if people would like to read the review, where can they find it?

Helen: Thanks Mike. The review is published online in the Cochrane Library, which is at Cochrane Library dot com, and the review can be found by typing a search for 'adjunctive therapies for osteoarthritis'.