title: Fluoroscopic, magnetic resonance imaging, and electrophysiologic assessment of shoulders with massive tears of the rotator cuff.
abstract: BACKGROUND
  It was the purpose of this paper to analyze structural, functional, and electrophysiologic variables that may determine preserved overhead function for patients with massive rotator cuff tears.
  
  
  METHODS
  Nineteen patients (20 shoulders) were prospectively included in either the pseudoparalytic (n = 9) or the non-pseudoparalytic group (n = 11). Fatty infiltration was graded according to Goutallier, and anterior (subscapularis) and posterior (infraspinatus and teres minor) tear extension was graded 0 (no involvement) to 4 (full tear) on magnetic resonance imaging. Glenohumeral and scapulothoracic rhythm was assessed by fluoroscopic motion analysis, and electromyographic evaluation of the deltoid muscle was performed.
  
  
  RESULTS
  We found no significant difference of fatty infiltration of the supraspinatus (3.9 vs 3.6), infraspinatus (3.9 vs 3.8), and teres minor (1.7 vs 0.6) or of the posterior tear extension (2.6 vs 2.0) between pseudoparalytic and non-pseudoparalytic shoulders. Global tear extension in the parasagittal plane (205° vs 163°) and subscapularis involvement (2.6 vs 1.2), however, showed significant differences between the two groups, and no patient with a full-thickness supraspinatus and infraspinatus tear with extension into the inferior half of the subscapularis was able to lift the arm to 90°. Fluoroscopic assessment revealed almost total loss of active glenohumeral abduction in the pseudoparalytic group.
  
  
  CONCLUSIONS
  Despite global tear extension, the single most important predictor for preserved shoulder function is the integrity of the inferior subscapularis insertion. Furthermore, electromyographic evaluation identifies a well-differentiated deltoid innervation as beneficial for a well-preserved shoulder function, but it does not protect from pseudoparalysis.
authors.affiliation: Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland. Electronic address: karl.wieser@balgrist.ch.
authors.forename: Karl
authors.initials: K
authors.lastname: Wieser
authors.affiliation: Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Rahm
authors.affiliation: Department of Neurology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Schubert
authors.affiliation: Department of Radiology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Fischer
authors.affiliation: Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.
authors.forename: Mazda
authors.initials: M
authors.lastname: Farshad
authors.affiliation: Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Gerber
authors.affiliation: Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland.
authors.forename: Dominik C
authors.initials: DC
authors.lastname: Meyer
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D057645:Deltoid Muscle / Q000503:physiopathology*; D004576:Electromyography; D005471:Fluoroscopy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D018908:Muscle Weakness / Q000503:physiopathology; D011446:Prospective Studies; D016059:Range of Motion, Articular; D017006:Rotator Cuff / Q000000981:diagnostic imaging*; D000070636:Rotator Cuff Injuries; D012421:Rupture / Q000150:complications / Q000503:physiopathology; D012785:Shoulder Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery
keywords: EMG; Massive rotator cuff tear; fatty infiltration; myotendinous retraction; pseudoparalysis