Multiple etiologies have been implicated in the pathogenesis of rotator cuff tear mainly of two types: extrinsic, such as subacromial and internal impingement, tensile overload, repetitive stress; intrinsic, such as poor vascularity, alterations in material properties, matrix composition, and aging. The work of Yamamoto [1] statistically identified that the risk factors associated with rotator cuff tears in the general population were a history of trauma, the dominant arm, and age. In subjects who were under 49 years of age, rotator cuff tears were more strongly associated with the dominant arm and a history of trauma. These results indicated that extrinsic factors were more closely associated in the tears of the younger patients. The same study found 6.7 % of patients in their 40s with rotator cuff ruptures, 12.8 % in their 50s, 25.6 % in their 60s, 45.8 % in their 70s, and 50.0 % in their 80s, with the prevalence increasing with age. Despite these results, 16.9 % of the subjects without symptoms have also a rotator cuff rupture.
