Supraspinatus outlet view in the diagnosis of stages II and III impingement syndrome

PURPOSE: To compare supraspinatus outlet view (SOV) findings at different stages of the impingement syndrome (IS) with findings in asymptomatic age- and sex-matched controls. MATERIAL AND METHODS: Pre-operative SOVs were obtained of 37 shoulders of patients scheduled for unilateral open repair of a full-thickness rotator cuff tear (stage III IS) and 74 shoulders of patients scheduled for open (n=46) or arthroscopic (n=28) acromioplasty for tendinitis (stage II IS). Each view of a patient's shoulder was paired with a control view obtained from an age- and sex-matched person with no shoulder problems (n=111). RESULTS: There were no significant differences in acromial morphology as evaluated on the scale devised by BIGLIANI et al. or in the tilt, slope or length of the acromion between the study groups and their controls. However, hooked acromion seemed to be more common in the patients. The thickness of the anterior part of the acromion at the tendinitis stage and the acromial angle at the tear stage of IS were the only parameters that showed significant differences between patients and controls. CONCLUSION: Variation of the morphology of the acromion as evaluated on a basis of the SOV is associated with IS, but the association is weak and its value in the diagnosis of IS is therefore only as an adjunctive to other diagnostic modalities.