Background: The association between tuberosity cysts and rotator cuff tears (RCTs) and the nature of the major contributing factors to tuberosity cyst formation continue to be controversial. The purpose of our study was to evaluate the strength of associations of RCT and various factors involved in the chronicity of RCT with tuberosity cysts, using magnetic resonance imaging (MRI) and radiographs.
Methods: We reviewed consecutive patients with various disease entities between August 2004 and July 2013. After excluding unsuitable patients, this study involved 1007 shoulders of 906 consecutive patients. Each tuberosity cyst was categorized as an anterior greater tuberosity (GT), posterior GT, lesser tuberosity, and bare-area cyst. The odds ratios (ORs) and 95% confidence intervals (CIs) between the tuberosity cysts and various factors were evaluated by logistic regression analyses; p-value was set below 0.05.
Results: Anterior GT cysts and posterior GT cysts on MRI or anterior GT cysts on radiographs were significantly associated with supraspinatus tendon (SST) tears ( p ≤ 0.019) and infraspinatus tendon (IST) tears ( p ≤ 0.004). Among the shoulder pathologies, RCTs only significantly associated with cyst formation (OR 4.23, 95% CI 3.17-5.65; p < 0.001). The retraction grade of Patte was significantly associated with anterior GT cyst (OR 3.65, 95% CI 2.42-5.48; p < 0.001).
Conclusion: Detecting an anterior GT cyst in a radiograph, even a low prevalence, in a patient with symptomatic shoulder indicates a need to consider RCT, especially of the SST, IST, and a high possibility of a retracted tear.
Keywords: MRI; radiographs; rotator cuff tear; tuberosity cyst.