What are types of acromions that contribute to rotator cuff injuries?

Updated: Oct 25, 2018
  • Author: Gerard A Malanga, MD; Chief Editor: Craig C Young, MD  more...
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Bigliani and Morrison classified 3 types of acromions based on cadaveric examination, as follows [6] :

  • Type I – Flat

  • Type II – Curved

  • Type III – Hooked

Bigliani noted a significant increase in rotator cuff tears in curved (type II) and hooked (type III) acromions. This work has led to the belief that rotator cuff pathology occurs secondary to the type of acromion and that treatment should be directed toward correcting pathoanatomic changes by making the acromion smoother and flatter. However, debate exists concerning whether the acromion shape causes pathology to the rotator cuff or is a result of a diseased rotator cuff that secondarily causes bony changes to the acromion.

Neer proposed that acromial changes are secondary to rotator cuff tendinopathy. [3] According to this view, the initial process is migration of the humeral head superiorly with repeated impingement, followed by secondary bony changes to the undersurface of the anterior acromion. This view was further corroborated by the work of Yamanaka and Fukuda, who found a greater incidence of partial rotator cuff tears on the articular surface of the rotator cuff rather than the bursal surface. [22] If acromial changes actually caused rotator cuff tendinopathies, one would expect the opposite (ie, higher incidence of pathology on the bursal surface).

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