title: In vivo shoulder function after surgical repair of a torn rotator cuff: glenohumeral joint mechanics, shoulder strength, clinical outcomes, and their interaction.
abstract: BACKGROUND
  Surgical repair of a torn rotator cuff is based on the belief that repairing the tear is necessary to restore normal glenohumeral joint (GHJ) mechanics and achieve a satisfactory clinical outcome.
  
  
  OBJECTIVE
  Dynamic joint function is not completely restored by rotator cuff repair, thus compromising shoulder function and potentially leading to long-term disability.
  
  
  METHODS
  Controlled laboratory study and Case series; Level of evidence, 4.
  
  
  METHODS
  Twenty-one rotator cuff patients and 35 control participants enrolled in the study. Biplane radiographic images were acquired bilaterally from each patient during coronal-plane abduction. Rotator cuff patients were tested at 3, 12, and 24 months after repair of a supraspinatus tendon tear. Control participants were tested once. Glenohumeral joint kinematics and joint contact patterns were accurately determined from the biplane radiographic images. Isometric shoulder strength and patient-reported outcomes were measured at each time point. Ultrasound imaging assessed rotator cuff integrity at 24 months after surgery.
  
  
  RESULTS
  Twenty of 21 rotator cuff repairs appeared intact at 24 months after surgery. The humerus of the patients' repaired shoulder was positioned more superiorly on the glenoid than both the patients' contralateral shoulder and the dominant shoulder of control participants. Patient-reported outcomes improved significantly over time. Shoulder strength also increased over time, although strength deficits persisted at 24 months for most patients. Changes over time in GHJ mechanics were not detected for either the rotator cuff patients' repaired or contralateral shoulders. Clinical outcome was associated with shoulder strength but not GHJ mechanics.
  
  
  CONCLUSIONS
  Surgical repair of an isolated supraspinatus tear may be sufficient to keep the torn rotator cuff intact and achieve satisfactory patient-reported outcomes, but GHJ mechanics and shoulder strength are not fully restored with current repair techniques.
  
  
  CONCLUSIONS
  The study suggests that current surgical repair techniques may be effective for reducing pain but have not yet been optimized for restoring long-term shoulder function.
authors: Bone and Joint Center, Henry Ford Hospital, Detroit, MI 48202, USA. bey@bjc.hfh.edu
authors: Michael J
authors: MJ
authors: Bey
authors: Cathryn D
authors: CD
authors: Peltz
authors: Kristin
authors: K
authors: Ciarelli
authors: Stephanie K
authors: SK
authors: Kline
authors: George W
authors: GW
authors: Divine
authors: Marnix
authors: M
authors: van Holsbeeck
authors: Stephanie
authors: S
authors: Muh
authors: Patricia A
authors: PA
authors: Kolowich
authors: Terrence R
authors: TR
authors: Lock
authors: Vasilios
authors: V
authors: Moutzouros
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D019637:Orthopedic Procedures / Q000379:methods / Q000534:rehabilitation; D017060:Patient Satisfaction; D011859:Radiography; D017006:Rotator Cuff / Q000503:physiopathology / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D012782:Shoulder / Q000000981:diagnostic imaging / Q000502:physiology / Q000601:surgery*; D020069:Shoulder Pain / Q000503:physiopathology / Q000534:rehabilitation / Q000601:surgery; D013708:Tendon Injuries / Q000503:physiopathology / Q000534:rehabilitation / Q000601:surgery*; D016896:Treatment Outcome