title: Natural history of infraspinatus fatty infiltration in rotator cuff tears.
abstract: OBJECTIVE
  Muscular fatty infiltration (FI) represents an important prognostic factor in rotator cuff repair. The goal of this study was to analyze the natural history of infraspinatus FI in rotator cuff tears to determine the timing of the appearance and the speed of progression of this phenomenon.
  
  
  METHODS
  The preoperative MRI or CT-arthrograms of 1688 patients operated for rotator cuff tears were reviewed. The degree of infraspinatus FI was correlated with the type of tendon tear, patient sex, dominant hand, presence of traumatic injury, delay between the onset of symptoms and imaging studies, and age of the patients at imaging. Infraspinatus FI was graded on axial images according to Goutallier classification and described as minimal (stage 0 or 1), medium (stage 2), and severe (stages 3 and 4). Statistical regression was used to determine the most significant factors.
  
  
  RESULTS
  Infraspinatus FI increased significantly in presence of an infraspinatus tendon tear and when multiple tendons were torn (P < .0005), with increasing delay between the onset of symptoms and imaging studies (P < .0005) and increasing patient age (P < .0005). Medium FI appeared on average 2 and a half years after the onset of symptoms, and severe FI appeared at an average of 4 years after symptom onset.
  
  
  CONCLUSIONS
  Larger tendon tears, longer delays after tendon rupture and older patient age are associated with more severe and frequent FI. Stage 2 FI appears at an average of 2 and a half years after the onset of symptoms, and surgical repair should be done within this time frame if possible.
authors.affiliation: Centre Orthopédique Santy, Lyon, France.
authors.forename: Barbara
authors.initials: B
authors.lastname: Melis
authors.forename: Bryan
authors.initials: B
authors.lastname: Wall
authors.forename: Gilles
authors.initials: G
authors.lastname: Walch
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000367:Age Factors; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology*; D011379:Prognosis; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D017006:Rotator Cuff / Q000473:pathology / Q000601:surgery; D000070636:Rotator Cuff Injuries; D012421:Rupture; D012720:Severity of Illness Index; D013708:Tendon Injuries / Q000473:pathology* / Q000601:surgery; D013997:Time Factors