Introduction: Intraarticular pathologies are a common finding during arthroscopy for rotator cuff lesions. Both rotator cuff tears as well as cartilage lesions have been described as correlating with the acromion index.
Methods: In the current study, we aimed to determine the incidence of intraarticular lesions in calcifying tendinitis, to compare the incidence in patients with partial- and full-thickness tears of the rotator cuff, and to determine the acromion index in these groups. The incidence and type of accompanying intraarticular lesions were compared between three consecutive, age-matched groups of 64 patients each: those with calcifying tendinitis (group A), and those with partial- (group B) and full-thickness rotator cuff tears (group C). Also, the acromion index was measured from plain radiographs and compared between the groups.
Results: The incidence of intraarticular pathology was 43% in group A, 41% in group B and 84% in group C. The differences between groups A and C as well as B and C were significant (p < 0.0001), but not between groups A and B (p = 0.858). Even though the acromion index was larger in group C than in the other two groups, the difference was not significant (A vs. B, p = 0.505; A vs. C, p = 0.180; and B vs. C p = 0.446). The incidence and type of intraarticular lesions in calcifying tendinitis are comparable to age-matched shoulders with partial- rather than full-thickness rotator cuff tears.
Conclusion: The acromion index is not different between shoulders with calcifying tendinitis, and partial- or full-thickness rotator cuff tears.