title: The effect of supraspinatus tears on glenohumeral translations in passive pitching motion.
abstract: BACKGROUND
  Supraspinatus tears are common in pitchers. However, the effect of these tears on glenohumeral (GH) mechanics is incompletely understood.
  
  
  OBJECTIVE
  To describe the effect of supraspinatus tears and repairs on GH kinematics during an abbreviated throwing motion using the intact shoulder girdle. The hypothesis was that supraspinatus tears would lead to an increase of GH translation in the coronal plane and supraspinatus repairs would restore GH kinematics.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Six shoulders from 3 fresh-frozen cadavers were tested in a novel 7 degrees of freedom robotic testing system. Torsos were mounted and the wrist was pinned to an actuator mounted on an upper frame. After the deltoid was removed, the shoulders were studied during an abbreviated throwing motion (ATM) from maximum external rotation to the midcoronal plane to establish a baseline. The ATM was repeated after creation of a 1-cm supraspinatus tear, after creation of a 3-cm supraspinatus tear, and after repair with a transosseous equivalent (TOE) technique. Retroreflective bone markers and high-speed infrared cameras were used to measure GH kinematics and calculate the center of rotation of the GH joint (CORGH) instantaneously.
  
  
  RESULTS
  The 1- and 3-cm supraspinatus tears did not significantly alter GH translation. The TOE repair shifted the CORGH posteriorly, as evidenced by a significant decrease in the overall GH translation in all 3 planes (P = .003, .019, and .026, for x-y, y-z, and x-z planes, respectively).
  
  
  CONCLUSIONS
  In contrast to a TOE repair of the supraspinatus tendon, isolated supraspinatus tears did not perturb GH kinematics in this cadaveric model of the throwing shoulder.
  
  
  CONCLUSIONS
  In throwing athletes, treatment of rotator cuff tears should be addressed with caution to avoid an unintended alteration in GH kinematics due to overtightening of the tendon.
authors.affiliation: Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA Orthopaedic Department, University Hospital Basel, Basel, Switzerland.
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Mueller
authors.affiliation: Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA Orthopaedic Department, University Hospital Basel, Basel, Switzerland.
authors.forename: Claudio
authors.initials: C
authors.lastname: Rosso
authors.affiliation: Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Vahid
authors.initials: V
authors.lastname: Entezari
authors.affiliation: Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Brett
authors.initials: B
authors.lastname: McKenzie
authors.affiliation: Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hasebroock
authors.forename: Andrea
authors.initials: A
authors.lastname: Cereatti
authors.affiliation: Information Engineering Unit, POLCOMING Department, University of Sassari, Sassari, Italy.
authors.forename: Ugo
authors.initials: U
authors.lastname: Della Croce
authors.affiliation: Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA anazaria@bidmc.harvard.edu.
authors.forename: Ara
authors.initials: A
authors.lastname: Nazarian
authors.affiliation: Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Arun J
authors.initials: AJ
authors.lastname: Ramappa
authors.affiliation: Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: DeAngelis
mesh_terms: D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D012371:Robotics; D017006:Rotator Cuff / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D012785:Shoulder Joint / Q000502:physiology*; D053441:Suture Anchors; D013536:Suture Techniques
keywords: glenohumeral joint; pitching; shoulder biomechanics; supraspinatus tear; translation