Shoulder instability: classification and methods of clinical examination

The shoulder is a complex joint whose stability relies on both dynamic and static factors. Dysfunction of one of these components gives rise to shoulder problems. Diagnosis of shoulder instability depends on a detailed history and appropriate physical examination. Despite the presence of many tests, none has proved to be purely diagnostic for shoulder instability. Therefore, these tests should be regarded as a part of the diagnostic procedure rather than a referral to diagnosis itself. Tests performed to assess laxity and instability are different in nature; thus, positive laxity tests do not necessarily show instability unless supported by further evidence. The reliability of the tests for superior labrum anterior-posterior lesions has not been adequately validated by clinical studies and few anatomical studies have examined the effect of these tests on the superior labral complex.