title: Effects of exercise therapy for the treatment of symptomatic full-thickness supraspinatus tears on in vivo glenohumeral kinematics.
abstract: BACKGROUND
  The high incidence of rotator cuff disease combined with high failure rates for nonoperative treatment of full-thickness rotator cuff tears underlines the importance of improving nonoperative management of rotator cuff tears. The study objective was to assess changes in in vivo glenohumeral kinematics of patients with a symptomatic full-thickness supraspinatus tear before and after a 12-week exercise therapy program. It was hypothesized that successful exercise therapy would result in improved kinematics (smaller translations and increased subacromial space).
  
  
  METHODS
  Five patients were recruited for the study and underwent dynamic stereoradiography analysis before and after a 12-week exercise therapy protocol to measure changes in glenohumeral joint translations and subacromial space during coronal plane abduction. Strength and patient-reported outcomes (American Shoulder and Elbow Surgeons; Disabilities of the Arm, Shoulder and Hand; Western Ontario Rotator Cuff Index) were also evaluated.
  
  
  RESULTS
  After therapy, no subject went on to receive surgery. It was found that the contact path length of the humerus translating on the surface of the glenoid was reduced by 29% from 67.2% ± 36.9% glenoid height to 43.1% ± 26.9% glenoid height (P = .036) after therapy. Minimum acromiohumeral distance showed a small increase from 0.9 ± 0.6 mm to 1.3 ± 0.8 mm (P = .079). Significant improvements in strength and patient-reported outcomes were also observed (P < .05).
  
  
  CONCLUSIONS
  Successful exercise therapy for treatment of small full-thickness supraspinatus tears results in improvements in glenohumeral joint kinematics and patient-reported outcomes through increases in rotator cuff muscle strength and joint stability. This study may enable identification of prognostic factors that predict the response of a patient with a rotator cuff tear to exercise therapy.
authors.affiliation: Orthopaedic Robotics Laboratory, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: R Matthew
authors.initials: RM
authors.lastname: Miller
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Popchak
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Dharmesh
authors.initials: D
authors.lastname: Vyas
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Tashman
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: Irrgang
authors.affiliation: Orthopaedic Robotics Laboratory, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Volker
authors.initials: V
authors.lastname: Musahl
authors.affiliation: Orthopaedic Robotics Laboratory, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA. Electronic address: genesis1@pitt.edu.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Debski
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D011379:Prognosis; D059869:Radiostereometric Analysis; D017006:Rotator Cuff / Q000000981:diagnostic imaging* / Q000503:physiopathology; D000070636:Rotator Cuff Injuries; D012785:Shoulder Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology; D013708:Tendon Injuries / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*
keywords: Shoulder; biomechanics; exercise therapy; glenohumeral joint; kinematics; rotator cuff tear