Ultrasound-guided Shoulder Injections Help Fortify Medical Decision-making

By: Gregory C. Mallo, M.D.

In 1977, Charles S. Neer II, M.D. first identified suspected rotator cuff disease by eliciting pain with passive abduction in the scapula plane and holding the arm in internal rotation. This became known as the “Neer sign.” Years later, temporary relief of a painful Neer sign with an injection of local anesthetic into the subacromial space indicated a positive “Neer test,” which increased diagnostic utility.

In today’s modern medicine, practitioners consider the subacromial injection a diagnostic staple for identifying shoulder pathology. More recently, the ubiquity of portable ultrasound technology has improved injection accuracy, further solidifying its use as a powerful diagnostic tool.

There have been several excellent articles in the literature discussing a myriad of diagnostic shoulder injections that many of us are familiar with. These include injections into the subacromial space, the acromioclavicular (AC) joint, the long head of the biceps tendon (LHBT), glenohumeral joint and suprascapular notch.

Thus, the purpose of this article is not to review these various indications and techniques, but instead to share how ultrasound-guided diagnostic injections dramatically impact some unique situations.

One such situation involves the treatment of shoulder pain in patients with moderate to severe glenohumeral joint osteoarthritis. In these cases, obvious X-ray findings of mild to moderate joint space narrowing may draw the clinician’s attention away from the actual source of pain. Yet, a history of severe anterior shoulder pain that is focal and reproducible when palpated may implicate biceps pathology as the true pain generator. A guided injection to the LHBT sheath confirms this suspicion. In this way, injection also helps quantify the amount of pain coming from the extra-articular biceps versus glenohumeral joint arthrosis.

Dramatic short-term relief of symptoms after a biceps groove injection may indicate that biceps pathology is responsible for nearly all the patient’s daily symptoms. In these cases, a patient can avoid the risk and morbidity of arthroplasty in favor of a less invasive biceps tenodesis or tenotomy.

Another complex clinical scenario where judicious use of diagnostic injection simplifies the treatment algorithm involves the patient with prior shoulder surgery. In such cases, MRI and other advanced imaging modalities are difficult to interpret.

Thus, in the absence of obvious exam findings or an MRI showing an overt recurrent full-thickness supraspinatus tear, for example, the source of pain can be difficult to elicit in this complex patient population.

A detailed physical examination of shoulder motion, as well as special testing for the biceps-labral complex and AC joint, may suggest a diagnosis, but reliable confirmation of this diagnosis is obtained only with a guided injection.

In addition, partial pain relief, or even no relief, after an injection also helps paint the overall clinical picture.

A glenohumeral joint injection for suspected adhesive capsulitis; a biceps groove injection for refractory tenosynovitis; or an AC joint injection for arthrosis indicates that particular pathology’s contribution to a patient’s overall pain experience.

We often discover that revision surgery involves addressing new pathology as opposed to revising a previous repair.

In practice, I will often ask the patient, “If surgery provided the same amount of relief as the injection, but relief would be permanent, would you want surgery?” The answer to this question guides surgical indications as well as patient expectations.

From the earliest days of our medical education, the information gleaned from a detailed patient history combined with a focused physical exam was championed over test results and imaging reports. As Dr. Neer taught us decades ago, injections about the shoulder act as diagnostic adjuncts to a detailed physical exam and serve to fortify medical decision-making.

References

1. Finnoff, J.T., Berkoff, D., Brennan, F., DiFiori, J., Hall, M.M., Harmon, K., Lavallee, M., Martin, S., Smith, J., Stovak, M. “American Medical Society for Sports Medicine Recommended Sports Ultrasound Curriculum for Sports Medicine Fellowships.” Clinical Journal of Sports Medicine. 2015 Jan;25(1):23-9.
2. McFarland, E., Bernard, J., Dein, E., Johnson, A. “Diagnostic Injections About the Shoulder.” Journal of the American Academy of Orthopaedic Surgeons. 2017 Dec;25(12):799-807. doi: 10.5435/JAAOS-D-16-00076
3. Phillips, N. “Tests for Diagnosing Subacromial Impingement Syndrome and Rotator Cuff Disease.” Journal of Shoulder and Elbow Surgery. 2014;6(3):215-221. doi: 10.1177/1758573214535368