PURPOSE: To prospectively assess the frequency of abnormal sonographic findings in patients with posttraumatic shoulder pain and/or disability in whom ultrasound (US) was not considered and to assess the effect of sonographic findings on working diagnosis and therapeutic strategy, to analyze the possible role of US in the diagnostic workup of these patients. METHODS: A survey was performed under general practitioners and orthopedic surgeons. They were requested to refer patients with persistent posttraumatic complaints for an US examination of the shoulder and to fill out a questionnaire concerning working diagnosis and therapy. In 50 patients examinations were performed separately by two radiologists. Findings were confirmed with additional radiographs and/or MRI and/or surgery. Four weeks after the US examination, the survey was repeated to inquire about changes in diagnosis and/or treatment that resulted from US. RESULTS: US showed relevant pathology in 45 (90%) of 50 patients, a proximal humerus fracture in 25 (50%) patients, and a rotator cuff tear in 43 (86%) patients. Twenty-three (92%) fractures were accompanied by a rotator cuff tear, and 23 (54%) rotator cuff tears were accompanied by a fracture. Ten fractures were initially missed radiographically. US findings changed the working diagnosis and therapeutic strategy in 37 (74%) and 26 (52%) patients, respectively. CONCLUSION: In patients with posttraumatic shoulder complaints, US showed a high rate (90%) of relevant pathology. This changed the initial working diagnosis in 74% of the patients and the therapeutic strategy in more than half of the patients. Active referral for US examination may identify these abnormalities in an earlier phase and improve clinical outcome.