The Subacromial Impingement Syndrome (SIS) is the most prevalent disorder of the shoulder in primary health care. Acromionplasty, as the main surgical treatment of SIS, is one of the most performed... Show moreThe Subacromial Impingement Syndrome (SIS) is the most prevalent disorder of the shoulder in primary health care. Acromionplasty, as the main surgical treatment of SIS, is one of the most performed orthopedic surgeries. However, its results are highly variable. Possibly, there are different etiologic subgroups of patients, that might need specific treatment approaches. Several etiologic mechanisms have been described for subacromial narrowing or __impingement__: i.e. 1) structural causes, including acromion shape, subacromial bony spurs, osteophytes; 2) narrowing of the subacromial space due to humerus cranialisation in patients with (micro)instability, or scapular dyskinesia; 3) intrinsic mechanisms such as primary degenerative tendinopathy of the rotator cuff. The aim of this thesis is to unravel the clinical entity __Subacromial Impingement Syndrome__ and to develop methods for identifying distinct etiological patient subgroups that need specific diagnostics and treatment strategies. To this end, we explore the terminological problems and opinions on the main characteristics of SIS amongst international health practitioners, study the prevalence of previously reported etiologic mechanisms in patients with SIS symptoms, develop clinical and biomechanical methods to evaluate and categorize patients with SIS symptoms in diagnostic subgroups, and compare treatment outcomes in trials and follow-up studies. Show less
