When someone with shoulder pain to told to consider acromioclavicular joint surgery, they will typically accept the surgery because they think it will help them get to sport or work sooner, or they will ask, “It won’t get better by itself?” or “Is there anything else we can do.” The answers to those questions should be made in a consultation. In this article we will examine the research surrounding someone with an MRI, that has been told to have the surgery, and are exploring options.
The MRI and its impact on the surgical decision
I have an extensive article on this site: What is a normal shoulder MRI and what is an abnormal shoulder MRI? that covers research and outcomes of MRIs in shoulder pain. In that article I discuss people with bad shoulder pain and terrible looking MRIs. I also point out that shoulder MRIs may present faulty or inaccurate information. In our many years experience, we have found that when MRI is the sole governing tool relied upon by doctors to recommend treatment, a patient will often be sent to a surgery with a shoulder that is not that bad. Let’s look at some research.
MRI is not helpful in making the diagnosis of acromioclavicular joint arthritis
In the medical journal Shoulder and Elbow, October 10, 2018: (1) Doctors in the United Kingdom made these observations after investigating whether magnetic resonance imaging (MRI) scans can accurately diagnose arthritis of the acromioclavicular joint.
- “MRI is not helpful in making the diagnosis of acromioclavicular joint arthritis. A focused history and clinical examination should remain the mainstay for surgical decision making.
What does the MRI show?
When there is no gross anatomical problems or the patient does not report that pain, and exploratory MRI may find the following as outlined in this June 2020 paper in the Journal of shoulder and elbow surgery. (2)
“Women had a higher chance of presenting with acromioclavicular joint pain than men. Patients with edema on magnetic resonance imaging were more likely to present with pain than patients without edema. Patients with acromioclavicular joint pain had longer shoulder pain duration than patients without pain, and subchondral bone edema on histologic examination was more frequent in patients with pain.”
Does the MRI show too much? Not enough?
In this study the MRI is showing too much, and this can lead to an unneeded surgery
A May 2022 study (3) questioned treatment methods for people suffering from acromioclavicular joint osteoarthritis that were seeking care for something else. Here is what the researchers reported: “Radiographic osteoarthritis of the acromioclavicular joint is a common incidental finding and an uncommon reason for people to seek care for shoulder symptoms. . . Given that a high base rate of incidental disease creates a low pre-test odds that radiological findings of disease correspond with symptoms, diagnosis of symptomatic acromioclavicular joint osteoarthritis is subject to substantial inaccuracy and should be made sparingly, mindful of the potential harms of a diagnosis that can lead to an ablative surgery.”
Management of acromioclavicular joint osteoarthritis
Another May 2022 study (4) asked patients, what where the treatment goals they were seeking from acromioclavicular joint surgery. In this study sixteen patients participated in five patient focus group discussions including 10 patients with acromioclavicular joint instability and six patients with acromioclavicular joint osteoarthritis. What the study revealed is that medical guidelines for assisting these patients did not include solutions to the problems that patients reported as being important to them. What were these problems?
The researchers wrote: “Although many factors affecting the acromioclavicular joint were common to instability and osteoarthritis pathology, several factors appear to be unique to each and do not appear in existing acromioclavicular joint joint metrics. . . Patients in this study identified several themes relevant to assessment and rehabilitation program development including pain location, type of pain (eg. burning pain), and specific activities that induced pain that do not exist in current existing tools. Our finding that certain themes were only raised in either acromio-clavicular instability or osteoarthritis suggests that there may be differences in important outcomes for patients depending on the underlying cause of the acromio-clavicular joint pathology.”
There appears to be no consensus on the best practice
A study from 2018 (5) demonstrates that acromioclavicular joint pain management remains at issue. “Shoulder pain secondary to acromioclavicular joint pain is a common presentation in primary and secondary care but is often poorly managed as a result of uncertainty about optimal treatment strategies. Osteoarthritis is the commonest cause. Although acromioclavicular pain can be treated non-operatively and operatively, there appears to be no consensus on the best practice pathway of care for these patients, with variations in treatment being common place.”
“Conservative and surgical treatments are both effective in acromioclavicular joint osteoarthritis management. However, available data did not allow to establish the superiority of one technique over another.”
A 2021 study (6) continued this line of research seeking to clarify the management of acromioclavicular joint osteoarthritis, as well as to identify any existing gaps in the current knowledge of treatment. The researchers examined nineteen studies that assessed 861 shoulders. Mean age of participants was about 49 years old. Average follow-up was about 44 months. Four studies reported functional results after conservative treatment, whereas 15 studies were focused on surgical management. No studies directly compared conservative and surgical treatment. Seven studies reported a surgical approach after failure of previous conservative treatment. All studies reported functional improvement and pain relief. Complication rate was low. Overall methodological quality of included studies was very low. Conclusion: “Conservative and surgical treatments are both effective in acromioclavicular joint osteoarthritis management. However, available data did not allow to establish the superiority of one technique over another.”
“The specific source of persistent pain in the acromioclavicular joint remains ambiguous.”
A March 2022 study (7) looked at the acromioclavicular disk as a potential source of pain in AC joint injuries. The study notes: “Injuries of the acromioclavicular joint are common shoulder injuries that often lead to pain and dysfunction of the affected shoulder. Regardless of operative or nonoperative treatment, a relatively large number of patients remain symptomatic and experience pain. However, the specific source of persistent pain in the acromioclavicular joint remains ambiguous.” What this study determined was: the presence of nerve fibers within the intra-articular disk of the acromioclavicular joint suggesting that the disk itself could be an independent source of pain after injury and thus a possible explanation for recalcitrant pain after treatment.
Pain after rotator cuff surgery: “The acromioclavicular joint should be considered as a potential site of persistent pain after ARCR for small-to-medium rotator cuff tears.”
A December 2023 study wrote (8): “Bone marrow edema in the acromioclavicular joint may occur after arthroscopic rotator cuff repair, resulting in persistent postoperative acromioclavicular joint pain. . . The rate of occurrence of bone marrow edema in the acromioclavicular joint after arthroscopic rotator cuff repair was 9.96 %. Patients with bone marrow edema were significantly more likely to have acromioclavicular joint tenderness and positive cross-body adduction test. Bone marrow edema in the acromioclavicular joint often occurs within 6 months to 1 year after arthroscopic rotator cuff repair of small-to-medium rotator cuff tears, suggesting a relationship with postoperative functional improvement of the shoulder joint.” The acromioclavicular joint should be considered as a potential site of persistent pain after ARCR for small-to-medium rotator cuff tears.
References
1 Singh B, Gulihar A, Bilagi P, Goyal A, Goyal P, Bawale R, Pillai D. Magnetic resonance imaging scans are not a reliable tool for predicting symptomatic acromioclavicular arthritis. Shoulder & Elbow. 2017 Aug 17:1758573217724080.
2 de Souza Bomfim L, Ejnisman B, Belangero PS. Histologic and magnetic resonance image evaluation in acromioclavicular joint osteoarthritis. JSES international. 2020 Jun 1;4(3):536-41.
3 Rossano A, Manohar N, Veenendaal WJ, van den Bekerom MP, Ring D, Fatehi A. Prevalence of acromioclavicular joint osteoarthritis in people not seeking care: A systematic review. Journal of Orthopaedics. 2022 Jul 1;32:85-91.
4 Aldhuhoori S, Almasri M, Nicholls SG, Pollock JW, Rollins M, Howard L, Lapner P. What outcomes are important in the recovery from acromio-clavicular (AC) joint pathology? A focus group study with patients and surgeons. Disability and Rehabilitation. 2020 Aug 14:1-9.
5 Chaudhury S, Bavan L, Rupani N, Mouyis K, Kulkarni R, Rangan A, Rees J. Managing acromio-clavicular joint pain: a scoping review. Shoulder & Elbow. 2018 Jan;10(1):4-14.
6 Soler F, Mocini F, Djemeto DT, Cattaneo S, Saccomanno MF, Milano G. No differences between conservative and surgical management of acromioclavicular joint osteoarthritis: a scoping review. Knee Surgery, Sports Traumatology, Arthroscopy. 2021 Jul;29(7):2194-201.
7 Ostermann RC, Moen TC, Siegert P, Bukowsky C, Lang S, Heuberer PR, Pauzenberger L. Acromioclavicular Disk as a Potential Source of Pain in AC Joint Injuries. The American Journal of Sports Medicine. 2022 Mar;50(4):1039-43.
8 Kajita Y, Takahashi R, Sagami R, Harada Y, Iwahori Y. Bone marrow edema in the acromioclavicular joint after arthroscopic rotator cuff repair. Journal of Orthopaedic Science. 2023 Dec 22.
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