title: The prevalence of rotator cuff tears: is the contralateral shoulder at risk?
abstract: BACKGROUND
  Rotator cuff tears are a common cause of pain and disability of the shoulder. Information on the prevalence and identification of potential risk factors could help in early detection of rotator cuff tears and improve treatment outcome.
  
  
  OBJECTIVE
  Patients treated for a symptomatic rotator cuff tear on one side have a higher prevalence of rotator cuff tears and decreased shoulder function on the contralateral side compared with an age- and sex-matched group of healthy individuals.
  
  
  METHODS
  Case control study; Level of evidence, 3.
  
  
  METHODS
  One group consisted of 55 patients who had been arthroscopically treated on one shoulder for rotator cuff tear (tear group). In this group, the nonoperated contralateral shoulder was examined. For comparison, the matching shoulder in a control group consisting of 55 subjectively healthy individuals matched by age (±1 year) and sex to the tear group was included. Diagnosis of a rotator cuff tear was made by ultrasound. Outcomes were measured using the Constant score.
  
  
  RESULTS
  The prevalence of supraspinatus tears was significantly higher (P < .0001) in the tear group (67.3%) compared with the control group (11.0%). The Constant score for the activities of daily living subscale, however, was significantly lower (18.4) in the tear group compared with the control group (19.9; P = .012). No other subcategory score nor the overall score showed a significant difference. There was a significantly higher tear prevalence in the tear group of patients aged between 50 and 59 years (P < .001) and 60 and 69 years (P = .004). No tear was diagnosed in the control group in individuals younger than 60 years.
  
  
  CONCLUSIONS
  Patients treated for partial and full-thickness rotator cuff tears have a significantly higher risk of having a tear on the contralateral side and have noticeable deficits in their shoulder function regarding activities of daily living even if the tear is otherwise asymptomatic.
authors: Dennis Liem, Department of Orthopedics and Tumor Orthopedics, University Hospital Muenster, Albert-Schweitzer-Str 33, 48149 Muenster, Germany. dl@dennisliem.de.
authors: Dennis
authors: D
authors: Liem
authors: Vera Elisa
authors: VE
authors: Buschmann
authors: Carolin
authors: C
authors: Schmidt
authors: Georg
authors: G
authors: Gosheger
authors: Tim
authors: T
authors: Vogler
authors: Tobias L
authors: TL
authors: Schulte
authors: Maurice
authors: M
authors: Balke
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D001182:Arthroscopy; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D016059:Range of Motion, Articular / Q000502:physiology; D012306:Risk; D000070636:Rotator Cuff Injuries; D012421:Rupture / Q000453:epidemiology / Q000209:etiology / Q000473:pathology / Q000601:surgery; D020069:Shoulder Pain / Q000209:etiology* / Q000601:surgery*
keywords: asymptomatic; contralateral shoulder; prevalence; rotator cuff tear; shoulder function; ultrasound