Subacromial impingement and tendinopathy

You go to the doctor with a complaint of severe shoulder pain. The pain is at the top and side of your shoulder and causing you great discomfort. You tell your doctor that the pain is much worse when you do anything where you have to reach over your head. Further, you tell your doctor that you also have a hard time sleeping at night because the pain is worse when you lay down. You may get an examination and your doctor may look for how much range of motion you have in your shoulder. If you have a lot of pain, you may be recommended to get an MRI of your shoulder.

Once the pain is determined to come from the subacromial space of the shoulder, that is the area of the rotator cuff tendons and the subacromial bursa, then rotator cuff tendinopathy, (shoulder impingement) is often diagnosed. The impingement occurs when the Acromion’s underside, presses against the rotator cuff tendons causing wear and tear.

In April 2023 in the online medical journal StatPearls (x), researchers write: “Shoulder impingement syndrome is most commonly seen in individuals who participate in sports and activities that require repetitive overhead activities, including but not limited to handball, volleyball, swimming, carpenters, painters, and hairdressers. Other extrinsic risk factors that may predispose to the development of impingement syndrome include bearing heavy loads, infection, smoking, and fluoroquinolone antibiotics.”

Shoulder Impingement and compression

“Swimmer’s shoulder”

If you are a swimmer, then you may have heard your subacromial shoulder pain called “swimmer’s shoulder.” Swimmer’s shoulder should be thought of as more than an impingement only disorder. Many people I see have a significant problem with shoulder instability leading their shoulder pain to be a multi-cause problem. This was point out by a paper in the journal Current reviews in musculoskeletal medicine.(1)

“Swimmer’s shoulder is the term used to describe the problem of shoulder pain in swimmers. Originally described as supraspinatus tendon impingement under the coracoacromial arch, it is now understood that several different pathologies can cause shoulder pain in competitive swimmers, including subacromial impingement syndrome, overuse and subsequent muscle fatigue, scapular dyskinesis, and laxity and instability.”

Overhead throwing athlete’s shoulder

A December 2022 paper (x) also describes these same issues in overhead throwing athletes. “Recent investigation has shown that throwers and other overhead athletes are more likely to present with subtle subluxation events rather than discrete dislocations as their primary symptom. While overhead athletes with discrete anterior (front of shoulder) dislocation events are likely to begin with non-operative management, many progress on to surgical intervention. . . The optimal management of shoulder instability in the overhead athlete continues to be a controversial topic due to the complex work-up, an increasing number of surgical options with varying indications, and low volume of high-quality studies comparing any of the treatment options. . .”

Subscapularis and supraspinatus tendinopathy

A July 2022 paper (13) examined the prevalence of an MRI documented injury in elite swimmers’ shoulders compared to non-swimmer’s shoulders. Sixty (aged 16-36 years) elite Australian swimmers and 22 healthy active, age and gender matched controls (aged 16-34 years) entered the study. All participants completed a demographic, and training load and shoulder pain questionnaire and underwent shoulder MRI.

  • Subscapularis and supraspinatus tendinopathy was the most common tendon abnormality identified in swimming participants, being reported in at least one shoulder in 48/60 (73 %) and 46/60 (70 %) swimmers, respectively. There was no significant difference between dominant and non-dominant shoulders for either tendinopathy, however, grade 3 tendinopathy was significantly more prevalent in subscapularis than in supraspinatus
  • Compared with controls, significantly more abnormalities were reported in swimmers’ shoulders in both subscapularis and supraspinatus tendons along with the labrum and acromioclavicular joint.

Conclusions: “This data confirms that tendon abnormality is the most common finding in elite swimmers’ shoulders. Furthermore, that subscapularis tendinopathy is not only as common as supraspinatus but has a greater prevalence of grade 3 tendinopathy.” Next the researchers of this study suggested, the MRI is a tool to help assess the swimmer’s shoulder, but not be the sole tool of assessment. Here the researchers wrote: “With significant varied abnormalities including tendinopathy being so common in both symptomatic and asymptomatic shoulders of swimming athletes’, clinicians should consider imaging findings alongside patient history, symptom presentation and clinical examination in determining their relevance in the presenting condition.”

The surgery to fix this – Arthroscopic subacromial decompression – is not effective – surgeons suggest not even offering it

In the late 1980’s and early 1990’s Arthroscopic subacromial decompression (ASD) was developed to be able to go in and shave away the acromion and give the tendon’s more space. Initial reports indicated good success rate. A 1987 study from the Department of Orthopaedic Surgery, University of California at Los Angeles wrote: “Eighty-eight percent of the cases were rated “satisfactory” (excellent or good), and 12% were rated “unsatisfactory” (fair or poor),” when performed by experienced physicians.(2) However, as the years went on, surgery began to fall out of favor as we will see in this progression of research that takes us to 2023.

As the years went on, doctors began to doubt the surgery.

In 2013, Dr. Robert Zaray Tashjian published research the Clinical journal of sports medicine suggesting that surgical interventions for subacromial impingement syndrome do not reveal one surgical technique to be better than another, nor do they show that surgery is superior in any way to conservative interventions.(3)

Further, data in the medical journal Arthroscopy showed when young athletes have arthroscopic stabilization surgery, it must be emphasized to the patients and their families that the recurrence rate (the need for another surgery) following arthroscopic procedures is higher in young people than in the adult population.(4)

Research like this suggests that shoulder impingement surgery may not be the fastest way back to sports or activity and the prospect of more surgery needs to be considered.

A patient with problems of the rotator cuff or shoulder impingement may think that surgery will be a quick fix. However, surgery is an invasive procedure that often requires lengthy recovery and physical therapy even if it is successful. Further, even “successful” surgery may not relieve the pain, and shoulder weakness can remain. Complications can also include nerve damage and increased weakness.

One study from doctors at New York University and published in The Journal of the American Academy of Orthopaedic Surgeons noted that “most patients experience pain relief and functional improvement following arthroscopic rotator cuff repair, but some continue to experience symptoms post-operatively. Patients with so-called failed rotator cuff syndrome, that is, with continued pain, weakness, and limited active range of motion following arthroscopic rotator cuff repair, present a diagnostic and therapeutic challenge.”(5)

Subacromial decompression no better than placebo surgery – 2018

The University of Helsinki reports on a landmark study from their researchers published July 19, 2018 in the British Medical Journal, Finnish researchers show that one of the most common surgical procedures in the Western world is probably unnecessary. Keyhole surgeries of the shoulder are useless for patients with “shoulder impingement”, the most common diagnosis in patients with shoulder pain.

“These results show that this type of surgery is not an effective form of treatment for this most common shoulder complaint. With results as crystal clear as this, we expect that this will lead to major changes in contemporary treatment practices,” said the study’s principal investigators chief surgeon Mika Paavola and professor Teppo Järvinen from the Helsinki University Hospital and University of Helsinki.

“By ceasing the procedures which have proven ineffective, we would avoid performing hundreds of thousands useless surgeries every year in the world”, Järvinen points out. You can read the press release here

Arthroscopic subacromial decompression for subacromial pain syndrome no better than a placebo surgery 2021

A paper from October 2021 (9) continued along the same line of research, exploring whether or not  arthroscopic subacromial decompression was able to get people back to work faster. In this paper patients received one of three treatments:

  • One group had an actual arthroscopic subacromial decompression surgery.
  • One group had a diagnostic arthroscopy which was consider the placebo surgery.
  • One group had exercise therapy

The researchers found no difference in the ability of any of these three treatments to get people back to work, writing: “”Arthroscopic subacromial decompression provided no benefit over diagnostic arthroscopy or exercise therapy on return to work in patients with shoulder impingement syndrome. We did not find clinically relevant predictors of return to work either.”

“Arthroscopic treatment should no longer be offered to people with subacromial impingement.” 2022

An August 2022 (11) opinion from Monash University writes: “Arthroscopic treatment should no longer be offered to people with subacromial impingement. In many people, subacromial impingement (or subacromial pain syndrome) is self-limiting and may not require any specific treatment. This is evident by the fact that almost 50% of people with new-onset shoulder pain consult their primary care doctor only once. The best-available evidence from randomized controlled trials indicates that glucocorticoid injection provides rapid, modest, short-term pain relief. Exercise therapy has also been found to provide no added benefit over glucocorticoid injection. Subacromial decompression (bursectomy and acromioplasty) for subacromial pain syndrome provides no important benefit on pain, function, or health-related quality of life. Acromioplasty does not improve the outcomes of rotator cuff repair.”

Research: Subacromial decompression – little if any benefit – but the surgery is still recommended

In March 2019, surgeons at McMaster University in Canada published their review which suggested evidence that surgical intervention has little, if any, benefit for impingement pathology in the middle-aged patient. In this study published in the Journal of the Canadian Medical Association (CMAJ Open (6)) the researchers stated emphatically:

  • “Surgical intervention for subacromial impingement syndrome may have little if any benefit with respect to pain and functional outcomes in the short and long term in comparison with nonoperative treatments such as exercise and physiotherapy alone. Our findings are strengthened by the inclusion of randomized controlled trials, a sufficiently large pooled sample of patients, confidence intervals that excluded our threshold of a minimal clinical importance and low heterogeneity across studies.” In other words, the researchers were pretty sure the surgery did not work.

At Monash University in Australia, doctors published a 2019 study (7) which made these suggestions:

  • The data in this (study) do not support the use of subacromial decompression in the treatment of rotator cuff disease manifest as painful shoulder impingement. High-certainty evidence shows that subacromial decompression does not provide clinically important benefits over placebo in pain, function or health-related quality of life. Including results from open-label trials (with high risk of bias) did not change the estimates considerably. Due to imprecision, we downgraded the certainty of the evidence to moderate for global assessment of treatment success; there was probably no clinically important benefit in this outcome either compared with placebo, exercises or non-operative treatment.”

In August 2021, the question as to whether to have this surgery or not was the subject of a paper on developing patient decision aids to help the patient decide if this surgery is warranted for them.(8)

What is the formula for successful shoulder surgery?

A February 2022 study (10) examined current treatment methods for subacromial impingement to create an algorithm to optimize clinical outcomes in subacromial impingement based on current, high-level evidence.

  • A total of 35 studies comprising 3,643 shoulders (42% female, age 50 ± 5 years) were included.
  • Arthroscopic decompression with acromioplasty ranked much greater than arthroscopic decompression alone for pain relief and patient reported outcome improvement, but the difference in absolute patient reported outcome improvement was not statistically significant.
  • Corticosteroid injection alone demonstrated inferior outcomes across all 3 domains (pain, patient reported outcome improvement, and range of motion) with low cumulative rankings.
  • Physical therapy with Corticosteroid injection demonstrated moderate-to-excellent clinical improvement across all 3 domains (pain, patient reported outcome improvement, and range of motion) whereas Physical therapy alone demonstrated excellent range of motion and low-moderate outcomes in pain and patient reported outcome improvement domains. PT with nonsteroidal anti-inflammatory drugs or alternative therapies ranked highly for patient reported outcome improvement outcomes and moderate for pain and range of motion domains.
  • Finally, platelet-rich plasma injections demonstrated moderate outcomes for pain, forward flexion, and abduction with very low-ranking outcomes for patient reported outcome improvements and external rotation.

When surgery should be recommended? Possibly when patients suffer from  greater pain sensitivity to pain

A July 2022 study’s  (12) findings suggest that while reduction in pain and improved sleep quality can be found in many patients embarking on and completing an 8-week course of exercise, patients with higher pain sensitization or lower tolerance to pain may not see improvement after exercise.

Shoulder Impingement Surgery Alternatives

Although “impingement” refers specifically to pressure on the tendons and bursa in the shoulder, it is a generalized term often used to refer to shoulder pain of unknown origin. Other terms used to describe pain that cannot be pinpointed are tendinitis, tendinosis, and bursitis. When a patient comes into our office we will perform a detailed physical examination of the shoulder looking for pain generators. Spots on the shoulder that elicit a pain response when pressed. Typically these are the spots of damage.

By isolating the areas that are damaged and injecting these spots with stem cells we can be confident that healing can occur.

The connection between Subacromial impingement of the rotator cuff and the development of rotator cuff tendinopathy is clear. In many patients we see the impingement and the tendinopathy are only parts and contributing factors to shoulder pain.

This is pointed out in our research which appears in the peer-reviewed journal Cogent Medicine. The study can be found here in its entirety: Treatment of shoulder osteoarthritis and rotator cuff tears with bone marrow concentrate and whole bone marrow injections with a June 20, 2019 publication date.

Here we were able to demonstrate that:

  • Patients with rotator cuff tendinopathy and degenerative shoulder disease would benefit from either one and two stem cell treatments. Patients reported significant improvements in resting pain, active pain, and functionality score when compared to baseline.
  • These groups also experienced a 42.25% and 50.17% overall improvement respectively.
  • The group that received two treatments experienced statistically significant improvements in active pain when compared to the group that received one injection.
  • There were no significant outcome differences between rotator cuff tear and osteoarthritis patients.

Conclusions: Our study demonstrated that patients diagnosed with shoulder osteoarthritis or rotator cuff tears experienced symptomatic improvements in pain and functionality when injected with bone marrow concentrate (BMC) or whole bone marrow (WBM). Further randomized control studies are needed to validate these findings.


1 De Martino I, Rodeo SA. The swimmer’s shoulder: multi-directional instability. Current reviews in musculoskeletal medicine. 2018 Jun;11(2):167-71.
2 Ellman H. Arthroscopic subacromial decompression: analysis of one-to three-year results. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 1987 Jan 1;3(3):173-81.
3 Tashjian RZ. Is there evidence in favor of surgical interventions for the subacromial impingement syndrome? Clin J Sport Med. 2013 Sep;23(5):406-7. doi: 10.1097/01.jsm.0000433152.74183.53.
4 Castagna A, Delle Rose G, Borroni M, Cillis BD, Conti M, Garofalo R, Ferguson D, Portinaro N. Arthroscopic stabilization of the shoulder in adolescent athletes participating in overhead or contact sports. Arthroscopy. 2012 Mar;28(3):309-15. doi: 10.1016/j.arthro.2011.08.302. Epub 2011 Nov 30.
5 Strauss EJ, McCormack RA, Onyekwelu I, Rokito AS. Management of failed arthroscopic rotator cuff repair. J Am Acad Orthop Surg. 2012 May;20(5):301-9.
6 Khan M, Alolabi B, Horner N, Bedi A, Ayeni OR, Bhandari M. Surgery for shoulder impingement: a systematic review and meta-analysis of controlled clinical trials. CMAJ open. 2019 Jan;7(1):E149.
7 Karjalainen TV, Jain NB, Page CM, Lähdeoja TA, Johnston RV, Salamh P, Kavaja L, Ardern CL, Agarwal A, Vandvik PO, Buchbinder R. Subacromial decompression surgery for rotator cuff disease. Cochrane Database of Systematic Reviews. 2019(1).
8 Zadro J, Jones C, Harris I, Buchbinder R, O’Connor DA, McCaffery K, Thompson RE, Karunaratne S, Teng MJ, Maher C, Hoffmann T. Development of a patient decision aid on subacromial decompression surgery and rotator cuff repair surgery: an international mixed-methods study. BMJ Open. 2021 Aug 30;11(8):e054032. doi: 10.1136/bmjopen-2021-054032. PMID: 34462283.
9 Bäck M, Paavola M, Aronen P, Järvinen TL, Taimela S. Return to work after subacromial decompression, diagnostic arthroscopy, or exercise therapy for shoulder impingement: a randomised, placebo-surgery controlled FIMPACT clinical trial with five-year follow-up. BMC Musculoskeletal Disorders. 2021 Dec;22(1):1-0.
10 Lavoie-Gagne O, Farah G, Lu Y, Mehta N, Parvaresh KC, Forsythe B. Physical Therapy Combined with Subacromial Cortisone Injection is a First-Line Treatment whereas Acromioplasty with Physical Therapy is Best if Non-Operative Interventions Fail for the Management of Subacromial Impingement: A Systematic Review and Network Meta-analysis. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2022 Feb 19.
11 Buchbinder R, Karjalainen TV, Gorelik A. Editorial Commentary: Arthroscopic Treatment Should No Longer Be Offered to People With Subacromial Impingement. Arthroscopy. 2022 Aug;38(8):2525-2528.
12 Lyng KD, Andersen JD, Jensen SL, Olesen JL, Arendt‐Nielsen L, Madsen NK, Petersen KK. The influence of exercise on clinical pain and pain mechanisms in patients with subacromial pain syndrome. European Journal of Pain. 2022 Jul 19.
13 Holt K, Delbridge A, Josey L, Dhupelia S, Livingston Jr G, Waddington G, Boettcher C. Subscapularis tendinopathy is highly prevalent in elite swimmer’s shoulders: an MRI study. Journal of Science and Medicine in Sport. 2022 Jul 14.


Creech JA, Silver S. Shoulder impingement syndrome. InStatPearls [Internet] 2021 Jul 26. StatPearls Publishing.

In June 2023, doctors published data (x) comparing the effectiveness of single intra-bursal injection of platelet-rich plasma versus corticosteroid under ultrasonography guidance for shoulder impingement syndrome.

This study was conducted on 60 participants with a clinical diagnosis of shoulder impingement syndrome. Thirty participants in each arm were given a single dose of either PRP or triamcinolone acetonide into the subacromial sub-deltoid bursa under ultrasonography guidance.

  • At 1 week, the triamcinolone arm showed a statistically significant reduction of pain when compared to PRP. In the long term, PRP showed statistically significant improvement in shoulder abduction, compared to the triamcinolone injection.

Hewavithana, P.B., Wettasinghe, M.C., Hettiarachchi, G., Ratnayaka, M., Suraweera, H., Wickramasinghe, N.D. and Kumarasiri, P.V.R., 2023. Effectiveness of single intra-bursal injection of platelet-rich plasma against corticosteroid under ultrasonography guidance for shoulder impingement syndrome: a randomized clinical trial. Skeletal Radiology, pp.1-8.

An April 2023 paper (x) Platelet-rich plasma (PRP) is a revolutionary treatment that harnesses the regenerative power of the body’s own platelets to promote healing and tissue regeneration. While PRP therapy has emerged as a promising option for augmenting biologic healing in the shoulder, the complexity of shoulder disorders makes it difficult to draw definitive conclusions about the efficacy of PRP across different conditions and stages of disease. However, the authors noted, “(only) recommend the use of PRP therapy for adhesive capsulitis and rotator cuff repair of medium to large tears. However, they do not recommend the use of PRP for subacromial impingement based on current evidence but leave the door open to “the clinician’s discretion to decide whether PRP therapy is appropriate for individual cases.”

Rosso C, Morrey ME, Schär MO, Grezda K. The role of platelet-rich plasma in shoulder pathologies: a critical review of the literature. EFORT Open Reviews. 2023 Apr 1;8(4):213-22.

An April 2023 paper (x) examined the effects of scapular mobilization in addition to an exercise program in people with subacromial impingement syndrome (SIS): “Scapular mobilization is a manual therapy technique widely used in the management of musculoskeletal disorders of the shoulder.”

  • Seventy-two adults with subacromial impingement syndrome were randomly allocated to 1 of 2 groups. The control group (36 people) participated in a 6-week exercise program, and the intervention group 36 people) participated in the same exercise program plus passive manual scapular mobilization. Conclusions: In the short-term, the addition of scapular mobilization did not provide significant clinical benefits in terms of function, pain or scapular motion in participants with 36 people.


An April 2023 study (x) summarizes the controversies surrounding Subacromial decompression (SAD) surgery.”

“Subacromial decompression (SAD) surgery remains a common treatment for individuals suffering from subacromial pain syndrome, despite numerous studies indicating that Subacromial decompression provides no benefit over conservative care. Surgical protocols typically recommend surgery only after exhausting conservative measures; however, there is no consensus in the published literature detailing (with) what constitutes conservative care “best practice” before undergoing surgery. To explore this question, investigators examined the data from forty-seven studies.

These studies covered physical therapy, home exercise programs, Subacromial injections, non-steroidal anti-inflammatories (NSAIDs). The duration of conservative care varied from 1.5 months to 16 months. The investigators concluded: “Conservative care that individuals with subacromial pain syndrome receive to prevent advancement to Subacromial decompression appears inadequate based on the literature. Interventions, such as physical therapy, subacromial injections, and non-steroidal anti-inflammatories (NSAIDs), are either underreported (as being prescribed) or not offered to individuals with subacromial pain syndrome prior to advancing to surgery. Many questions regarding optimal conservative management for subacromial pain syndrome persists.”

Signorino JA, Thompson AG, Young JL, Hando BR. Identifying Conservative Interventions for Individuals with Subacromial Pain Syndrome Prior to Undergoing a Subacromial Decompression: A Scoping Review. International Journal of Sports Physical Therapy. 2023;18(2):293.

Do You Have Questions? Ask Dr. Darrow

Most Popular