title: Retraction of supraspinatus muscle and tendon as predictors of success of rotator cuff repair.
abstract: BACKGROUND
  The structural failure rate of rotator cuff repair can exceed 50%. Important predictors for repair failure are preoperative fatty muscle infiltration and myotendinous retraction.
  
  
  OBJECTIVE
  To quantitatively assess the prognostic value of preoperative retraction of both the supraspinatus muscle and tendon for the outcome of supraspinatus repair.
  
  
  METHODS
  Cohort study; Level of evidence, 3.
  
  
  METHODS
  In 33 shoulders with complete supraspinatus tendon ruptures subjected to arthroscopic repair, magnetic resonance imaging (MRI) scans taken preoperatively and after a mean follow-up of 24 months were studied. The exact position of the lateral extension of the supraspinatus muscle and of the tendon end was evaluated and correlated with the preoperative stage of fatty infiltration (Goutallier) and the failure rate of tendon repair.
  
  
  RESULTS
  The mean lengthening of the muscle and tendon end was -3 mm and 4 mm in the failed repairs (n = 19) and 14 mm and 8 mm in the successful repairs (n = 14). If the supraspinatus had preoperative Goutallier stages 2 to 3 and a tendon length of less than 15 mm, the failure rate was 92%, but if the tendon length was greater than 15 mm, the failure rate was only 33%. With Goutallier stages 0 to 1, the corresponding failure rates were 57% and 25%, respectively.
  
  
  CONCLUSIONS
  Rotator cuff repair lengthens the tendon, even if the repair fails. The possibility to lengthen the myotendinous unit is related to the preoperative length of the tendon. The combination of Goutallier grading and preoperative tendon length appears to be a more powerful predictor for the reparability of a tendon tear than Goutallier grading alone.
authors.affiliation: Balgrist University Hospital, Orthopaedic Department, University of Zurich, Zurich, Switzerland.
authors.forename: Dominik C
authors.initials: DC
authors.lastname: Meyer
authors.forename: Karl
authors.initials: K
authors.lastname: Wieser
authors.forename: Mazda
authors.initials: M
authors.lastname: Farshad
authors.forename: Christian
authors.initials: C
authors.lastname: Gerber
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001182:Arthroscopy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000293:injuries* / Q000601:surgery; D011379:Prognosis; D017006:Rotator Cuff / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D012421:Rupture; D013708:Tendon Injuries / Q000175:diagnosis / Q000601:surgery*; D013710:Tendons / Q000601:surgery; D017211:Treatment Failure; D016896:Treatment Outcome