How to Improve the Efficacy of
Shoulder Injections

Corticosteroid injections serve as one of the principal medical treatments for shoulder pain¹, and recent research sheds new light on how this treatment can be made more consistently effective. Since 1997, numerous studies have used radiography or MRI to assess the accuracy of shoulder injections. Even in expert hands, accuracy of injections has proved to be as low as 29% in subacromial injections.² Three other studies have found overall accuracy to be closer to 70%.^3-5 Researchers have assessed the accuracy of subacromial injections and glenohumeral injections in the hands of rheumatologists, orthopedic surgeons and others. They have studied posterior, anteromedial, and anterior approaches. No one approach stands out as particularly accurate. These four studies also demonstrated that a physician’s confidence in the injection did not correlate strongly with an accurate infiltration. When the physician was confident that he had accurately infiltrated the correct structure, he was right only 66% to 75% of the time.

Where shoulder injections are concerned, accuracy seems to correlate with efficacy. One study published in 2002 suggests that when practitioners miss the subacromial bursa and instead infiltrate the deltoid muscle, that pain relief is still achieved.³ However, older and more recent studies found that accuracy affects the efficacy of shoulder injections.^2,5,6 The most recent study was the only one to use MRI to gauge injection accuracy, and it showed that practitioners will sometimes infiltrate many different structures in the course of one injection. Henkus et al also found that injections into the rotator cuff muscle caused increased pain.⁶

Hypothesizing that increased accuracy would improve the results of shoulder injections, Naredo et al compared ultrasound guided injections with palpation guided injections.⁶ They treated 41 shoulder pain patients with no history of trauma, chronic inflammatory arthritis, or physical therapy treatment. They assessed patients before injection and six weeks post-injection. On a visual analog scale for pain ranging from 0 to 100, the ultrasound guided injections created an average improvement of 35 points while the palpation guided injections created an average improvement of only seven points. On a shoulder function assessment scale of 0 to 70, the ultrasound guided injections created an average improvement of 15 points while the palpation guided injections only averaged a 6 point improvement.

Implications for your practice

• A high incidence of palpation guided injections that miss the subacromial bursa suggests that repeated palpation guided injections to the shoulder may be contraindicated.
• Neal Taub, MD, ABPM&R performs ultrasound guided injections at his physiatry practice in Charlotte. When shoulder injections are indicated, practitioners can consider a referral to Dr. Taub to attain the improved results demonstrated in Naredo’s research.
• Alternatively, when palpation guided injections fail to produce the desired results, a referral to Dr. Taub for ultrasound guided injections can be considered.

Ultrasound guidance can also improve outcomes when you refer for injections of the knee, sacroiliac, piriformis, wrist, or plantar fascia. The private, physiatry practice of Dr. Neal S. Taub is referral based. Dr. Taub treats for specific complaints falling under the physiatry realm of expertise and returns your patient to you for ongoing care.

References:

1. van der Windt DA, et al. “Effectiveness of corticosteroid injections versus physiotherapy for treatment of painful, stiff shoulder in primary care: randomised trial.” BMJ November 7, 1998; 317: 1292-6.
   
2. Eustace J, Brophy D, Gibney R. “Comparison of the accuracy of steroid placement with clinical outcome in patients with shoulder symptoms.” Ann Rheum Dis. 1997 Jan; 56 (1): 59-63.
   
3. Yamakado K. “The targeting accuracy of subacromial injection to the shoulder: an arthrographic evaluation.” Arthroscopy. 2002 Oct; 18 (8): 887-91.
   
4. Sethi P, El Attrache N. “Accuracy of intra-articular injections of the glenohumeral joint: a cadaveric study.” Orthopedics. 2006 Feb; 29 (2): 149-52.
   
5. Henkus H, Cobben L, Coerkamp E, et al. “The accuracy of subacromial injections: a prospective randomized magnetic resonance imaging study.” Arthroscopy. 22 (3): 277-82. March 2006.
   
6. Naredo E, Cabero F, Beneyto P. “A randomized comparative study of short term response to blind injection versus sonographic-guided injection of local corticosteroids in patients with painful shoulder.” J Rheumatol. 2004 Feb; 31(2) 308-14.