A recent study published in The Lancet evaluated whether surgery reduced shoulder pain, compared to a common treatment and a placebo surgery.
Shoulder pain is a common complaint at the doctor’s office. It can be debilitating for those affected, altering the quality of life and even keeping some sufferers out of employment.
One of the most common types of shoulder pain is subacromial pain, affecting 70% of those with shoulder pain. The term subacromial refers to a specific space within the shoulder that lies below a normal bony projection called the acromion.
Surgeons have long believed that the pain in the subacromial region is caused by a spur of bone or non-bony tissue impinging on the rotator cuff muscle as it runs through this space. As a result, a surgical procedure was developed in the 1970s, to remove the impinging bone spur or soft tissue. The procedure was named subacromial decompression surgery.
Is subacromial decompression surgery beneficial for shoulder pain?
Surgeons have been performing subacromial decompression surgery for shoulder pain more frequently. In the United Kingdom (UK) alone in 2010, 21,355 patients had this type of surgery. However, different research groups have published conflicting reports regarding how successful this surgery actually is for reducing shoulder pain.
A research group from the UK aimed to clarify the conflicting reports. They recently published their findings in The Lancet.
For the study, they enrolled 313 patients with shoulder pain into a study involving 32 different hospitals. To be eligible for the study, patients needed to meet the following criteria:
- Experienced shoulder pain for a minimum of three months
- Have intact rotator cuff tendons
- Have undergone an exercise therapy program
- Have had at least one steroid injection
The researchers aimed to see whether there is a difference in the degree of shoulder pain following decompression surgery, investigative surgery alone, or no treatment. They assigned the patients to one of these three groups at random.
Decompression surgery vs. investigative surgery
The patients in the groups having decompression surgery and investigative surgery all had two skin incisions and placement of a tiny camera, called an arthroscope, into the joint.
The decompression surgery differed from the investigative surgery in that it involved the placement of additional surgical instruments into the joint to remove the bone spurs or soft tissue present.
The investigative surgery involved simple placement of the arthroscope into the joint and the manipulation associated with looking around the joint, but no actual treatment.
The patients who were enrolled in the groups that underwent surgery were unaware of which type they were having: investigative or decompression. The purpose of withholding this information from the patient was to prevent any psychological effect or feeling better or worse that may occur through believing that they had or had not been treated.
The patients who were assigned to the group receiving no treatment had a clinical examination three months after they enrolled in the study. It was not feasible to prevent this group of patients from knowing the group to which they were assigned. The patients in all groups were evaluated for shoulder pain six and 12 months following surgery, or assignment to the group without treatment, through means of a questionnaire and a clinical examination.
No significant differences between the treatment groups
At the six and 12-month follow-up period, all patients had an improvement in their degree of shoulder pain. The researchers found that there was a small statistical difference between the patients that had surgery, of either type, compared to the patients who had no treatment. However, the difference was not clinically significant meaning that it was not enough for the researchers to be able to make a recommendation for surgery over no treatment at all.
Interestingly, when the patients who had decompression surgery were compared with those that had investigative surgery, no difference was seen. This finding led the researchers to conclude that there was no benefit of decompressing the joint space within the shoulder.
The authors discuss that the reason for the small statistical difference between patients who had surgery and those that did not may be the result of a placebo effect. They also discuss it may be due to the physiotherapy that this group of patients received after surgery.
To date, this was the largest study carrying out this kind of investigation. The results of the study caused the researchers to question the long-held belief that decompression surgery is beneficial for the treatment of subacromial shoulder pain. They suggest that the findings of their research be communicated to patients at the time that a decision on which treatment route to follow is made.
Written by Nicola Cribb, VetMB DVSc Dip.ACVS
Reference: Beard D, Rees J, Cook J, et al. Arthroscopic subacromial decompression for subacromial shoulder pain (CSAW): a multicentre, pragmatic, parallel group, placebo-controlled, three-group, randomised surgical trial. Lancet. 2018;391. doi:10.1016/S0140-6736(17)32457-1.
