According to a study, placebo treatment for hip osteoarthritis is as good as physiotherapy. Why?

Norwegian physiotherapy magazine’s editor-in-chief John Henry Strupstad writes in Fysioterapeuten number 6 2014 (1) about a study on the effect of physiotherapy for patients with hip osteoarthritis. The study concluded that physiotherapy was no better than placebo treatment (2). The result is hardly surprising. Explanation can be found in the theoretical basis of the treatments used and how those treatments are administered. An underestimation is made of the physiological and psychological mechanisms that explain the positive expectations that occur in the meeting between therapist and patient, the placebo effect (3-7). Similarly, the biomedical physiotherapy methods are overrated. Methods that many more or less mechanically trust and repeat in study after study without critically reflecting on whether the methods used are the right ones.

The patients received a total of ten treatments over twelve weeks. The first week two treatments, and then one treatment a week for six weeks. The following six weeks, one treatment every two weeks. It is a good design if one inadvertently wants to show that a physiotherapy intervention is not more effective than placebo. How can one expect that, so few treatments spread over such a long time have effects beyond positive expectations? The physiotherapy consisted of manual techniques described in the article as “hip thrust manipulation” and manual mobilization of the hip and lumbar spine. Patients also received deep massage, stretching, and four to six home exercises performed four times a week. The focus was on strengthening the hip abductors and quadriceps. The patients in the physiotherapy group also practiced functional balance and gait training. During the six-month long follow-up period, the patients in the active physiotherapy group would continue to do home exercises three times a week.

Why all this manual therapy for hip osteoarthritis patients? I just don’t get it. What is the theoretical basis for giving such treatment to all patients in the active physiotherapy group? I know that manual therapy still has a very high status in the physiotherapy profession and may therefore be uncritically tried on most things. I argue that such treatment of this patient group is maltreatment (iatrogenic treatment). Perhaps this is one of the explanations why significantly more negative experiences were recorded in the patients in the active physiotherapy group compared to the patients who received placebo treatment. As many as 19 of 46 patients (41%) in the active physiotherapy group reported adverse events during treatment compared to only 7 of 49 patients (14%) of those receiving placebo. This is astonishing information. The fact that the study shows that the active physiotherapy had significantly more nocebo effects (3-7) (the opposite of the placebo), indicates that the treatment was perhaps too heavy-handed and not suitable for the patient. Then it is this deep painful massage that certainly some patients have a positive expectation that it will help (8,9), but I can also imagine that some patients do not get the same positive experiences. The question is why we through our treatment methods should impose so much unnecessary pain on our patients.

So, the patients were given exercises with a focus on strengthening certain muscle groups. In this study, the researchers found it important to strengthen the abductors and quadriceps. Why only these muscles? What is the theoretical basis for why it is especially important to strengthen these muscles for patients with hip OA? Why not activate all functional movement patterns in the hip region, back and lower extremities? We know today that the central nervous system is organized to perform movements in functional movement patterns. The brain is not organized to recognize a single muscle, nor does it make sense for human function.

And then there was this thing with pain and strength (10). Why do we continue with this incorrect form of exercise for patients with pain? Why don’t we differentiate between strength and endurance training for healthy people with no pain and pain modulating exercise therapy for patients with pain? Today, there is a wealth of research that shows that it is the pain experience that is the problem (11). The pain affects psychological and physiological mechanisms that inhibit maximal muscle contractions (strength). The pain is also the reason why movements become uncoordinated. Reduced coordination equals reduced muscle power. It is the pain and the consequences of the pain that are the cause of reduced muscle strength. Therefore, the physiotherapeutic exercise therapy should focus on activating the body’s own pain modulating system so that the patient feels safe and motivated in the exercise therapy given. And in order for the exercise therapy to have positive clinical effects beyond a positive expectation (placebo), the exercise therapy must be carried out with an adapted exercise dose, which is carried out over a sufficiently long period of time, and which is gradually increased (12-14).

This perspective is missing in the study from Australia (2), which may also explain why the active physiotherapy was not better than the placebo. I argue that the theoretical basis for the exercises given is flawed. Too few exercises with too few series and too few repetitions of each series, altogether too low exercise dose. Did the patients even break a sweat from this exercise therapy? I don’t think so. When you include that the exercises were performed over too short a period and that there were too few exercises, it is not difficult to understand that the result turned out the way it did. The exercise dose was too low to have any positive clinical effect, too low to physiologically activate the body’s pain modulating system (15,16).

The placebo treatment was placebo ultrasound (not active ultrasound) which, together with a gel, was gently applied to the front and back of the hip by a non-blinded physiotherapist (the physiotherapist knew that he/she was giving a placebo treatment). Patients in the placebo group received the same number of treatments as in the active group. The placebo group received no exercises or manual therapy. After the treatment with placebo ultrasound and during the follow-up period of 6 months, the patients massaged gel over the hip for about 5 minutes 3 times a week. It is not difficult for me to understand that this intervention produces positive clinical effects equivalent to active physiotherapy. Who wouldn’t massage their hip with soft gel instead of doing boring, painful home exercises with rubber bands.

When a patient receives help from a physiotherapist, different parts of the central nervous system are activated. Various neurotransmitters and hormones are released which have a pain-relieving effect (placebo). Research shows that positive expectations not only affect pain but also psychological factors such as mood (depression), motor function, immune and endocrine systems. Man is a physiological being who constantly unconsciously/consciously evaluates his surroundings. This has been crucial for our survival and development here on earth. In our everyday life, we constantly evaluate what is good and what is bad. We do it at home and in the workplace. The patients do this in the meeting with the physiotherapist. Soft gel massaged gently on a painful hip is also done with a positive expectation that it will help. This activates the pain-modulating systems that provide pain relief (16-22). The massage with the soft gel activates various receptors in the skin which send nerve impulses to the spinal cord where various chemical reactions inhibit nociceptive input. At the same time, different brain areas are activated which stimulate the descending pain inhibitory system. Cortical and spinal inhibition of nociceptive input modulates, reshapes, and reduces hip pain.

Thinking about what is good and what is bad are basic cognitive mechanisms for living a good life. This is the placebo effect, or positive expectations as many prefer to describe these mechanisms as (3-6). Negative expectations, nocebo, are the opposite of placebo and activate different parts of the brain associated with anxiety (7). Nocebo activates stress reactions and can worsen symptoms. So, placebo is not a defect (23), it is being a whole living person (5,24).

As for many other professional groups in healthcare, the challenges lie ahead for us physiotherapists. One challenge is that effect studies are published daily that show that active physiotherapy is insufficient (25). I think the reason is that the exercise dose is generally too low, and the exercises given to painful, thus the theoretical basis for the exercise therapy treatment needs to be updated. If not, then the results from randomized controlled trial will be inconclusive or showing that physiotherapy is no better than placebo. For us to elevate our profession and truly be the professional group within healthcare that specializes in treating various forms of pain conditions, physiotherapists must have a good knowledge of what pain is. We must be open to new knowledge about how we use dosed exercise therapy for pain modulation, as an anti- allodynia-, anti-nociceptive therapy (26). We need to update ourselves in areas such as the psychology and physiology of pain (3-7,21,24). It is time we accept that there are no pain receptors, no pain impulses, knowledge that has existed for more than 40 years (27,28).

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