Calcific Tendonitis of the Shoulder: Protector or Predictor of Cuff Pathology? A Magnetic Resonance Imaging-Based Study

Purpose: The purpose of this investigation is to assess the incidence of rotator cuff tears in cases of calcific tendonitis and evaluate for differences in the incidences of rotator cuff tears by magnetic resonance imaging (MRI) between calcific lesions of different morphology, size, or location. Methods: This single-center study involved a retrospective chart review searching for patients from January 2010 to April 2017 with a diagnosis of calcific tendonitis of the shoulder based on review of all MRI reads done on patients with shoulder pain. Anteroposterior radiographic and MRI studies were reviewed by a musculoskeletal radiologist to assess calcific tendonitis morphology, size, distance from cuff insertion, and any rotator cuff tear. An additional radiologist evaluated calcific tendonitis size, morphology, and location to evaluate the reliability of these variables. Results: In the final cohort of 318 shoulders with calcific tendonitis, the incidence of concomitant rotator cuff tears was 56%. Of all 177 tears, 164 (93%) were partial-thickness and 13 (7%) were complete. Type III calcification morphology (cloudy with soft contour) was most frequently associated with rotator cuff tears and demonstrated an increased odds of tear by a factor of 1.8 (CI 95% 1.1-2.9).There was no statistical difference regarding calcification size or location prognosticating rotator cuff tears or tear thickness. Intraclass correlation coefficients for calcification size, morphology, and location were 0.78, 0.30, and 0.50, respectively. Conclusions: The incidence of rotator cuff tears in cases of calcific tendonitis in this cohort of patients who underwent MRI is higher than previously reported. Cloudyappearing calcified lesions showed a significant association with rotator cuff tears with an odds ratio of 1.8. Specific locations or sizes of calcified lesions do not appear to be reliable factors to predict concomitant rotator cuff tears. Interobserver agreement for these radiographic variables ranged from fair to substantial and prompt a cautious interpretation of these results.