title: Factors involved in the presence of symptoms associated with rotator cuff tears: a comparison of asymptomatic and symptomatic rotator cuff tears in the general population.
abstract: BACKGROUND
  The mechanisms underlying symptom development in rotator cuff tears are still unknown. The purpose of this study was to identify the characteristics associated with symptoms of rotator cuff tears.
  
  
  METHODS
  We performed a medical checkup on residents of a mountain village. The subjects of this study included 211 individuals with 283 shoulders in which a full-thickness rotator cuff tear was observed through ultrasonography. We recorded the subjects' background and medical history and then performed physical examinations. The subjects were divided into 2 groups according to whether they had any pain or disabilities that they felt subjectively while performing their usual daily activities. We determined the prevalence of an asymptomatic rotator cuff tear and conducted a statistical analysis to compare any differences between the 2 groups.
  
  
  RESULTS
  Of the 283 subjects, 65.4% with rotator cuff tears had no symptoms involving the shoulder. Asymptomatic rotator cuff tears were associated with a tear in the nondominant arm, a negative impingement sign, higher active forward elevation, and intact muscle strength in abduction and external rotation. A logistic regression analysis showed that a positive impingement sign, weakness in external rotation, and presence of a tear in the dominant arm were significantly associated with the presence of symptoms of rotator cuff tears.
  
  
  CONCLUSIONS
  In the general population, in approximately two-thirds of all rotator cuff tears, there are no symptoms, and the factors involved in the presence of symptoms associated with rotator cuff tears were identified to be a positive impingement sign, weakness in external rotation, and presence of a tear in the dominant arm.
authors: Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Gunma, Japan. a.yamamoto@gunma-u.ac.jp
authors: Atsushi
authors: A
authors: Yamamoto
authors: Kenji
authors: K
authors: Takagishi
authors: Tsutomu
authors: T
authors: Kobayashi
authors: Hitoshi
authors: H
authors: Shitara
authors: Toshihisa
authors: T
authors: Osawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D016059:Range of Motion, Articular / Q000502:physiology; D012399:Rotation; D017006:Rotator Cuff / Q000000981:diagnostic imaging; D000070636:Rotator Cuff Injuries; D019534:Shoulder Impingement Syndrome / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014463:Ultrasonography