Milwaukee shoulder: Correlating possible etiologic variables

The current study evaluated the relative correlation of apatite crystal-induced inflammation and rotator cuff deficiency in the development of cuff tear arthropathy. Thirty-seven patients with full thickness rotator cuff tears were evaluated by history, physical examination, and plain radiographs. Thirty patients had surgical intervention for their rotator cuff defects, and calipers were used intraoperatively to quantify the size of the tear in its largest diameter. The remaining seven patients were treated nonoperatively and the size of the tear was quantified using magnetic resonance imaging. Synovial fluid was obtained from all patients and analyzed for crystal content using an alizarin red stain. Synovial fluid also was analyzed for leukocyte count and differential, prostaglandin E., and matrix metalloproteinase. An unpaired Student's t test revealed that significantly higher levels of prostaglandin E-2 were found in the synovial fluid of patients with apatite crystals, shown by alizarin red stain. Chi squared analysis showed that patients with elevated crystal levels were significantly more likely to have large rotator cuff tears or glenolmmeral arthritis. Establishing such relations potentially can elucidate the etiology and treatment of this complex disorder.