Subscapularis management a critical part of shoulder arthroplasty, researcher says

Ultrasonography may help most in determining the extent or severity of subscapularis injuries.

Issue: November 2009

Subscapularis management during shoulder arthroplasty demands a critical attention to detail and may benefit most from the utilization of ultrasonography, according to investigators.

The findings were presented by John J. Brems, MD, at the 2009 Current Concepts in Joint Replacement Spring Meeting.

Brems said that studies document that ultrasonography offered more success than physical exams in evaluating the subscapularis. In addition, he outlined a number of examination options for various problems involving the rotator cuff.

Still, he pointed out, proper physical exams could eliminate the need for potentially expensive and unnecessary imaging in a number of cases.

Diagnosis

Brems reported that findings have indicated 67% of shoulder arthroplasty patients have clinical evidence of subscapularis failure and 92% have some dysfunction in their arm with a subscapularis tear.

“How is it diagnosed? I think the real question is: how valid are these tests?” Brems said. “Leesa Galatz, MD, and her group found that ultrasound is much more accurate in determining the integrity of the subscapularis following shoulder replacement surgery. Eighty-seven percent had ultrasound-proven subscapularis integrity despite the fact that there was much less correlation with the clinical examination findings.”

Subscapularis not to be ignored

According to Brems, the problem of subscapularis injury following shoulder arthroplasty can be prevented through careful attention to detail.

“Meticulous consideration of the subscapularis as a critical element is the most important issue,” he said. “It is not part of the routine closure that you send the resident to do while you go start your next case. A competent shoulder surgeon needs many arrows in his quiver with respect to subscapularis management.”

Brems reported that degenerative rotator cuff tears in the virgin shoulder tend to begin in the supraspinatus, propagating posteriorly. After shoulder arthroplasty, the earliest cuff tears occur in the subscapularis, often resulting in anterior instability. After 12 months or more, tears become more common in the supraspinatus and infraspinatus.

Still, Brems said the overall incidence of cuff tears following shoulder arthroplasty is low — around 2.5% on average.

The difference between subscapularis issues and supra- or infraspinatus issues can be simple.

“Excessive external rotation following shoulder arthroplasty usually suggests a subscapularis deficiency,” Brems said. “If there is anterior instability; think subscapularis deficiency. Weakness without pain means it is more likely the supra- and infraspinatus are going to be involved.”

Ultrasound: not yet proven

Moderator Evan L. Flatow, MD, felt it necessary to stress that the study Brems based his ultrasound findings on did not determine ultrasound to be definitively more effective.

“They didn’t prove that ultrasound was more accurate, they just assumed it was accurate,” Flatow said. “One of my only concerns about that is sometimes, in a non-impingement cuff tear, you can get a lengthening if the tendon does not heal. It will get sloppy, and it will look intact on an MRI or ultrasound but you will see the muscle tendon junction go a little bit more medially.”

For more information:

John J. Brems, MD, is the Fellowship Director for the Shoulder and Elbow Surgery Post Residency Training Program at the Cleveland Clinic. He can be reached at The Cleveland Clinic, 9500 Euclid Ave., Cleveland, Ohio 44195; 866-594-2091; e-mail: bremsj@ccf.org. He has no direct financial interest in any products or companies mentioned in this article.

Evan L. Flatow, MD, is a professor with the Mount Sinai School of Medicine. He can be reached at 5 East 98th St., 9th Floor, New York, NY 10029; 212-241-8892; e-mail: evan.flatow@msnyuhealth.org. He has no direct financial interest in any products or companies mentioned in this article.

References:

Armstrong A; et al. Ultrasound evaluation and clinical correlation of subscapularis repair after total shoulder arthroplasty. J Shoulder Elbow Surg. 2006;15(5):541-548.

Brems JJ. Rotator cuff tear following arthroplasty: Holes a poppin’. Paper #15, presented at the Current Concepts in Joint Replacement Spring 2009 meeting. May 18, 2009. Las Vegas.