Three-Dimensional Analysis of Acromial Morphologic Characteristics in Patients With and Without Rotator Cuff Tears Using a Reconstructed Computed Tomography Model

BACKGROUND: The relationship between rotator cuff tears and acromial shape has yet to be clarified. As a result, the most suitable location for acromioplasty for the treatment of rotator cuff tears is not known. PURPOSE: To determine whether any particular change in acromial shape is significantly associated with the presence of rotator cuff tears. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: From 2007 to 2010, we examined 25 consecutive patients with unilateral full-thickness rotator cuff tears who underwent arthroscopic repair and 17 consecutive patients with adhesive capsulitis but intact rotator cuffs who underwent arthroscopic capsular release. Before surgery, a reconstructed 3-dimensional computed tomography model was used to evaluate the acromial structure. Changes in the shape of the affected scapula were qualitatively evaluated relative to the unaffected, contralateral scapula by use of proximity mapping. Differences in acromial structure between affected and unaffected shoulders were assessed at the anterior, lateral, and medial edges and the inferior surface. The association between rotator cuff tear size and change in acromial structure was also evaluated. RESULTS: Rates of bony projection at the anterior (>2 mm) and lateral (>3 mm) edges of the acromion in patients with rotator cuff tears were significantly greater compared with rates in patients without rotator cuff tears (P < .01). Tear size was not correlated with changes in acromial structure (P = .37-.73). CONCLUSION: Bone spurs at the anterior and lateral edges of the acromion are associated with the presence of full-thickness rotator cuff tears in symptomatic patients.