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Rotator cuff tear incidence may be associated with osteophytes, not critical shoulder angle
In an evaluation of related factors for rotator cuff tears, results showed rotator cuff tears were more affected by heel-type osteophytes than critical shoulder angle.
Researchers categorized patients with (n=214) and without (n=109) full-thickness rotator cuff tears who underwent MRI and radiographic imaging of the shoulder into a high critical shoulder angle group of greater than 38°, a middle critical shoulder angle group of 33° to 38° and a low critical shoulder angle group of less than 33°. The presence of heel-type osteophytes and quadrangular osteophytes protruding inferiorly from the undersurface of the anterolateral acromion, like the heel of the shoe, were confirmed, while researchers excluded other types of osteophytes.
Results showed rotator cuff tears were present in 84.6% of the high critical shoulder angle group, 60.3% of the middle critical shoulder angle group and 68.3% of the low critical shoulder angle group. Researchers found 76.9%, 38.5% and 52.6% of patients without an osteophyte in the high, middle and low critical shoulder angle groups, respectively, had a rotator cuff tear. Rotator cuff tears were found in 92.3%, 80.3% and 92.2% of patients with an osteophyte in the high, middle and low critical shoulder angle groups, respectively, according to results. Univariate regression analysis showed rotator cuff tear was associated with critical shoulder angle group and the presence of osteophyte, but not with age or sex. Although presence of an osteophyte showed a significant relation with rotator cuff tear in multivariate logistic regression analysis, researchers found no significant relation between critical shoulder angle and rotator cuff tear.
“The present findings inform the clinically important suggestion that although [critical shoulder angle] CSA might be correlated with [rotator cuff tear] RCT, a CSA study without considering presence of an osteophyte should be interpreted with caution,” the authors wrote. – by Casey Tingle
Disclosures: The authors report no relevant financial disclosures.
Perspective
Back to TopKim and colleagues should be commended on their study "Rotator cuff incidence association with critical shoulder angle and subacromial osteophytes." This study tackled a controversial concept, the critical shoulder angle. Bjarnison and colleagues published that an increasing critical shoulder angle caused the deltoid to be directed superiorly in the coronal plane, and that this was associated with arthritis. Chalmers and colleagues performed a study and concluded that the critical shoulder angle was not related to the presence of rotator cuff disease, tear size or tear progression. The authors presently looked not only at the critical shoulder angle, but also at the presence of subacromial osteophytes. The presence of a heel-type osteophyte rather than the critical shoulder angle correlated with the presence of a rotator cuff tear. This information helps solidify the significance or lack thereof of the critical shoulder angle in contributing to rotator cuff tears. The one outstanding issue is the relationship between rotator cuff tears and subacromial osteophytes. The presence of a heel-type osteophyte correlates strongly with the presence of a rotator cuff tear. It is not known how or when these osteophytes arise, and whether they precede rotator cuff tears or are a secondary finding.
While in general, it supports an extrinsic mechanism for the generation of a rotator cuff tear, it doesn't exclude an intrinsic mechanism, so the debate continues. As always, there is likely contribution from both. Further study would be helpful to evaluate not only the progression of the rotator cuff tears, but also the development and progression of osteophytes in the etiology of the development of rotator cuff tears.
Shoulder and elbow reconstructive surgery
Icahn School of Medicine at Mount Sinai
Mount Sinai Health System