The results of the first placebo-controlled trial in shoulder surgery were published in The Lancet on Tuesday 21st November.
The study was jointly led by Prof Andrew Carr, lead for the NIHR (National Institute for Health Research) Oxford BRC Musculoskeletal Theme and Nuffield Professor of Orthopaedic Surgery at the University of Oxford, and Prof David Beard, co-Director of Oxford University’s Surgical Trials Intervention Unit.
The research found that although both types of surgery were slightly more effective at reducing pain compared to no treatment, the difference was small and not likely to result in a noticeable effect.
The surgery, called subacromial decompression, is one of the most commonly used surgeries in orthopaedics, and is being increasingly used in England – with the number of patients rising from 2,523 in 2000, to 21,355 in 2010.
The authors of the study say the findings call into question the value of this operation for shoulder impingement, when the tendon rubs and catches in the joint. They say patients considering undergoing the operation should be informed.
Prof Carr said: “Over the past three decades, patients with shoulder pain and clinicians have accepted this surgery in the belief that it provides reliable relief of symptoms, and has low risk of adverse events and complications.
“However, the findings from our study suggest that surgery might not provide a clinically significant benefit over no treatment, and that there is no benefit of decompression over placebo surgery.”
In the study, which involved 32 hospitals and 51 surgeons across the UK, 90 people underwent decompression surgery, 94 placebo surgery and 90 no treatment; they then completed questionnaires about their level of pain at six months.
Decompression surgery is a keyhole surgery that involves removing a small area of bone and soft tissue in the shoulder joint to open up the joint and prevent rubbing or catching when the arm is lifted.
In the placebo surgery, surgeons conducted a procedure to look inside the joint only.
Both surgeries were completed as keyhole procedures to ensure that patients were not aware of which surgery they had had. Surgery participants had one to four physiotherapy sessions afterwards, while those having no treatment only had a check-up appointment three months after the start of the trial.
Six and 12 months after they entered the trial, the participants completed questionnaires rating their level of pain (from 0-48, with a higher number meaning less pain). Overall, pain diminished in all three groups from the start of the trial.
At six months, people who had had decompression surgery and those who had had placebo surgery rated their pain at a similar level, with no statistical difference (32.7 points and 34.2 points, respectively).
Comparatively, both forms of surgery showed a small benefit over no treatment (29.4 points). However, the difference is unlikely to result in a noticeable difference in symptoms.
The authors suggest that the difference could be attributable to a number of factors, including a placebo effect related to surgery, a nocebo effect related to having no treatment, other unintended effects of the placebo surgery, or because people undergoing surgery were given physiotherapy and told to rest.
The authors state that the findings of the study should be communicated to patients and doctors considering this type of surgery, and that other ways of treating shoulder impingement, such as painkillers physiotherapy and steroid injections, should be considered.