NIHR Signal A surgical procedure for shoulder pain is less effective than previously thought

Published on 23 January 2018

An increasingly common surgical procedure for shoulder pain, subacromial decompression, was only slightly more effective than no treatment. In the first trial of this sort, improvements in pain and function following decompression or arthroscopy (a placebo surgery) did not reach a threshold of clinical importance compared with people allocated to no treatment at all.

This NIHR-funded study involved 313 people with shoulder pain that had not responded to physiotherapy and a steroid injection. The main intervention, decompression, involved removing any bony outgrowths that could have been causing the tendons around the shoulder to be “pinched”. This was compared with an arthroscopy used for investigation only; this did not include removing any bone or tissue. Those in the third “no treatment” arm did not receive any physiotherapy or advice.

The minimal differences between surgery and no treatment call into question the value of decompression for such a wide group of patients. It may be best reserved for people with a clear mechanical obstruction such as those with definite bony spurs.  

A surgical procedure for shoulder pain is less effective than previously thought

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Why was this study needed?

Shoulder pain affects 14 in every hundred adults in the UK. A common cause is inflammation and pressure on some of the tendons in the shoulder as they pass through a small arch termed the subacromial space. The arch is formed by the bone above the shoulder joint and a ligament attaching to the shoulder blade.  When the swollen tendon rubs on the acromion bone leading to pain on raising the arm. It can also cause the bone to produce spurs which can further inflame the tendon in a vicious cycle. 

Arthroscopic subacromial decompression opens up this space by removing bone and damaged soft tissue through keyhole surgery. In the UK in 2015/16 there were 30,669 admissions for this type of operation funded by the NHS. Rates of subacromial decompression have risen almost 8-fold from 5.2 per 100,000 population to 40.2 per 100,000 between 2001 and 2010 in England.

As it is not clear how well the procedure works, this study aimed to assess the effectiveness of the operation compared to a placebo procedure or nothing.

What did this study do?

This randomised controlled trial took place at 32 hospitals in the UK (51 surgeons). It included 313 adults with subacromial shoulder pain for at least three months that had not responded to exercise or at least one steroid injection. People with a rotator cuff tear were excluded from the study. They were randomised to either arthroscopic subacromial decompression, arthroscopy (an investigation with no bone or soft tissue removal) or no treatment. Both surgical groups received postoperative exercise therapy.

Interpretation of the results needs to take into account that a high proportion did not receive the intended intervention (23% decompression, 42% arthroscopy and 12% no treatment). The additional exercise therapy may have had a separate effect but would have been expected to increase the difference between the surgical groups and no treatment. Long and any differences between surgical waiting times may also have contributed to unfair between-group comparisons.

The main outcome measure for the study was the Oxford Shoulder Score assessed at six months, a validated patient-reported questionnaire it runs from 0 (worst) to 48 (best). A change of 4.5 points is the minimum change considered clinically important.

What did it find?

By six months:

  • There was no difference between the two surgical groups regarding pain and function (Oxford Shoulder Score). The decompression group average score improved from 25.2 to 32.7 while the arthroscopy group improved from 26.7 to 34.2 (mean difference [MD] ‑1.3, 95% confidence interval ‑3.9 to 1.3).
  • The no treatment group score improved slightly from 25.5 to 29.4 by six months. Though this improvement was less than for the decompression group (MD 2.8, 95% CI 0.5 to 5.2) and arthroscopy group (MD 4.2, 95% CI 1.8 to 6.6),
  • The differences were not considered to be clinically meaningful as they were less than 4.5 points.

By 12 months there had been further improvement in all groups. The decompression group scored 38.2, arthroscopy scored 38.4, and the score for those after no treatment had increased to 34.3. None of the differences between groups reached the threshold of clinical importance.

What does current guidance say on this issue?

The Royal College of Surgeons, Chartered Society of Physiotherapists and British Orthopaedic Association 2014 commissioning guideline recommends rest, simple pain killers and then physiotherapy for subacromial shoulder pain. A single injection of steroid can be tried, with a second injection after six weeks if there is a benefit. If there is still pain and disability, they recommend referral for surgical decompression.

The surgical recommendation is now being reconsidered by the British Orthopaedic Association and the British Elbow and Shoulder Society following the publication of this study.

What are the implications?

This study calls into question the benefits of surgical decompression. The small benefit of arthroscopy could have been a “placebo effect” or perhaps due to the post-operative physiotherapy this group received.

It may be that this, or a modified procedure, is effective for people with specific features such as bony spurs or there may be other subgroups of patients who could be further researched. This uncertainty could be discussed with patients alongside their non-surgical options.

These results might discourage surgeons from offering this procedure and dissuade patients from undergoing it. It is likely that the orthopaedic surgeons will consider this evidence and collectively review criteria for patient selection and any speciality guidance offered.

Citation and Funding

Beard DJ, Rees JL, Cook JL, et al. Arthroscopic subacromial decompression for subacromial

shoulder pain (CSAW): a multicentre, pragmatic, parallel group, placebo-controlled, three-group, randomised surgical trial. Lancet. 2017. [Epub ahead of print].

This project was funded by the National Institute for Health Research Biomedical Research Centre, Arthritis Research UK (Clinical Studies Grant 19707) and the Royal College of Surgeons (England).

Bibliography

BOA/BESS. Statement in response to recent studies regarding subacromial decompression. British Orthopaedic Association and British Elbow and Shoulder Society: London; 2017.

BESS/BOA/RCSEng. Commissioning Guide 2014: Subacromial Shoulder Pain. British Elbow & Shoulder Society, British Orthopaedic Association, Royal College of Surgeons for England (RCSEng): London; 2014.

NHS Digital. Hospital Admitted Patient Care Activity 2015/16: Procedures and Interventions. 2016.

Judge A, Murphy RJ, Maxwell R, et al. Temporal trends and geographical variation in the use of subacromial decompression and rotator cuff repair of the shoulder in England. Bone Joint J. 2014;96-B(1):70-4.

Why was this study needed?

Shoulder pain affects 14 in every hundred adults in the UK. A common cause is inflammation and pressure on some of the tendons in the shoulder as they pass through a small arch termed the subacromial space. The arch is formed by the bone above the shoulder joint and a ligament attaching to the shoulder blade.  When the swollen tendon rubs on the acromion bone leading to pain on raising the arm. It can also cause the bone to produce spurs which can further inflame the tendon in a vicious cycle. 

Arthroscopic subacromial decompression opens up this space by removing bone and damaged soft tissue through keyhole surgery. In the UK in 2015/16 there were 30,669 admissions for this type of operation funded by the NHS. Rates of subacromial decompression have risen almost 8-fold from 5.2 per 100,000 population to 40.2 per 100,000 between 2001 and 2010 in England.

As it is not clear how well the procedure works, this study aimed to assess the effectiveness of the operation compared to a placebo procedure or nothing.

What did this study do?

This randomised controlled trial took place at 32 hospitals in the UK (51 surgeons). It included 313 adults with subacromial shoulder pain for at least three months that had not responded to exercise or at least one steroid injection. People with a rotator cuff tear were excluded from the study. They were randomised to either arthroscopic subacromial decompression, arthroscopy (an investigation with no bone or soft tissue removal) or no treatment. Both surgical groups received postoperative exercise therapy.

Interpretation of the results needs to take into account that a high proportion did not receive the intended intervention (23% decompression, 42% arthroscopy and 12% no treatment). The additional exercise therapy may have had a separate effect but would have been expected to increase the difference between the surgical groups and no treatment. Long and any differences between surgical waiting times may also have contributed to unfair between-group comparisons.

The main outcome measure for the study was the Oxford Shoulder Score assessed at six months, a validated patient-reported questionnaire it runs from 0 (worst) to 48 (best). A change of 4.5 points is the minimum change considered clinically important.

What did it find?

By six months:

  • There was no difference between the two surgical groups regarding pain and function (Oxford Shoulder Score). The decompression group average score improved from 25.2 to 32.7 while the arthroscopy group improved from 26.7 to 34.2 (mean difference [MD] ‑1.3, 95% confidence interval ‑3.9 to 1.3).
  • The no treatment group score improved slightly from 25.5 to 29.4 by six months. Though this improvement was less than for the decompression group (MD 2.8, 95% CI 0.5 to 5.2) and arthroscopy group (MD 4.2, 95% CI 1.8 to 6.6),
  • The differences were not considered to be clinically meaningful as they were less than 4.5 points.

By 12 months there had been further improvement in all groups. The decompression group scored 38.2, arthroscopy scored 38.4, and the score for those after no treatment had increased to 34.3. None of the differences between groups reached the threshold of clinical importance.

What does current guidance say on this issue?

The Royal College of Surgeons, Chartered Society of Physiotherapists and British Orthopaedic Association 2014 commissioning guideline recommends rest, simple pain killers and then physiotherapy for subacromial shoulder pain. A single injection of steroid can be tried, with a second injection after six weeks if there is a benefit. If there is still pain and disability, they recommend referral for surgical decompression.

The surgical recommendation is now being reconsidered by the British Orthopaedic Association and the British Elbow and Shoulder Society following the publication of this study.

What are the implications?

This study calls into question the benefits of surgical decompression. The small benefit of arthroscopy could have been a “placebo effect” or perhaps due to the post-operative physiotherapy this group received.

It may be that this, or a modified procedure, is effective for people with specific features such as bony spurs or there may be other subgroups of patients who could be further researched. This uncertainty could be discussed with patients alongside their non-surgical options.

These results might discourage surgeons from offering this procedure and dissuade patients from undergoing it. It is likely that the orthopaedic surgeons will consider this evidence and collectively review criteria for patient selection and any speciality guidance offered.

Citation and Funding

Beard DJ, Rees JL, Cook JL, et al. Arthroscopic subacromial decompression for subacromial

shoulder pain (CSAW): a multicentre, pragmatic, parallel group, placebo-controlled, three-group, randomised surgical trial. Lancet. 2017. [Epub ahead of print].

This project was funded by the National Institute for Health Research Biomedical Research Centre, Arthritis Research UK (Clinical Studies Grant 19707) and the Royal College of Surgeons (England).

Bibliography

BOA/BESS. Statement in response to recent studies regarding subacromial decompression. British Orthopaedic Association and British Elbow and Shoulder Society: London; 2017.

BESS/BOA/RCSEng. Commissioning Guide 2014: Subacromial Shoulder Pain. British Elbow & Shoulder Society, British Orthopaedic Association, Royal College of Surgeons for England (RCSEng): London; 2014.

NHS Digital. Hospital Admitted Patient Care Activity 2015/16: Procedures and Interventions. 2016.

Judge A, Murphy RJ, Maxwell R, et al. Temporal trends and geographical variation in the use of subacromial decompression and rotator cuff repair of the shoulder in England. Bone Joint J. 2014;96-B(1):70-4.

Arthroscopic subacromial decompression for subacromial shoulder pain (CSAW): a multicentre, pragmatic, parallel group, placebo-controlled, three-group, randomised surgical trial

Published on 25 November 2017

Beard, D. J.,Rees, J. L.,Cook, J. A.,Rombach, I.,Cooper, C.,Merritt, N.,Shirkey, B. A.,Donovan, J. L.,Gwilym, S.,Savulescu, J.,Moser, J.,Gray, A.,Jepson, M.,Tracey, I.,Judge, A.,Wartolowska, K.,Carr, A. J.

Lancet , 2017

BACKGROUND: Arthroscopic sub-acromial decompression (decompressing the sub-acromial space by removing bone spurs and soft tissue arthroscopically) is a common surgery for subacromial shoulder pain, but its effectiveness is uncertain. We did a study to assess its effectiveness and to investigate the mechanism for surgical decompression. METHODS: We did a multicentre, randomised, pragmatic, parallel group, placebo-controlled, three-group trial at 32 hospitals in the UK with 51 surgeons. Participants were patients who had subacromial pain for at least 3 months with intact rotator cuff tendons, were eligible for arthroscopic surgery, and had previously completed a non-operative management programme that included exercise therapy and at least one steroid injection. Exclusion criteria included a full-thickness torn rotator cuff. We randomly assigned participants (1:1:1) to arthroscopic subacromial decompression, investigational arthroscopy only, or no treatment (attendance of one reassessment appointment with a specialist shoulder clinician 3 months after study entry, but no intervention). Arthroscopy only was a placebo as the essential surgical element (bone and soft tissue removal) was omitted. We did the randomisation with a computer-generated minimisation system. In the surgical intervention groups, patients were not told which type of surgery they were receiving (to ensure masking). Patients were followed up at 6 months and 1 year after randomisation; surgeons coordinated their waiting lists to schedule surgeries as close as possible to randomisation. The primary outcome was the Oxford Shoulder Score (0 [worst] to 48 [best]) at 6 months, analysed by intention to treat. The sample size calculation was based upon a target difference of 4.5 points (SD 9.0). This trial has been registered at ClinicalTrials.gov, number NCT01623011. FINDINGS: Between Sept 14, 2012, and June 16, 2015, we randomly assigned 313 patients to treatment groups (106 to decompression surgery, 103 to arthroscopy only, and 104 to no treatment). 24 [23%], 43 [42%], and 12 [12%] of the decompression, arthroscopy only, and no treatment groups, respectively, did not receive their assigned treatment by 6 months. At 6 months, data for the Oxford Shoulder Score were available for 90 patients assigned to decompression, 94 to arthroscopy, and 90 to no treatment. Mean Oxford Shoulder Score did not differ between the two surgical groups at 6 months (decompression mean 32.7 points [SD 11.6] vs arthroscopy mean 34.2 points [9.2]; mean difference -1.3 points (95% CI -3.9 to 1.3, p=0.3141). Both surgical groups showed a small benefit over no treatment (mean 29.4 points [SD 11.9], mean difference vs decompression 2.8 points [95% CI 0.5-5.2], p=0.0186; mean difference vs arthroscopy 4.2 [1.8-6.6], p=0.0014) but these differences were not clinically important. There were six study-related complications that were all frozen shoulders (in two patients in each group). INTERPRETATION: Surgical groups had better outcomes for shoulder pain and function compared with no treatment but this difference was not clinically important. Additionally, surgical decompression appeared to offer no extra benefit over arthroscopy only. The difference between the surgical groups and no treatment might be the result of, for instance, a placebo effect or postoperative physiotherapy. The findings question the value of this operation for these indications, and this should be communicated to patients during the shared treatment decision-making process. FUNDING: Arthritis Research UK, the National Institute for Health Research Biomedical Research Centre, and the Royal College of Surgeons (England).

Expert commentary

Disabling shoulder pain from a common condition called ‘subacromial impingement’ drives patients to seek effective treatment, but the best treatment strategy remains uncertain. A surgical ‘decompression’ has become commonplace, being increasingly offered to patients for this condition.

This study has raised further questions on the mechanism by which surgery may work and whether surgery is an appropriate early intervention for this condition.

It is time for us to re-consider and refine treatment pathways for this common cause of shoulder pain with more selective use of surgery for patients who are likely to derive the most benefit.

Amar Rangan, Professor of Orthopaedic Surgery, The James Cook University Hospital, Middlesbrough, Orthopaedic Research Lead, Royal College of Surgeons of England