title: The influence of superior labrum anterior to posterior (SLAP) repair on restoring baseline glenohumeral translation and increased biceps loading after simulated SLAP tear and the effectiveness of SLAP repair after long head of biceps tenotomy.
abstract: OBJECTIVE
  Biomechanical studies have shown increased glenohumeral translation and loading of the long head biceps (LHB) tendon after superior labrum anterior to posterior (SLAP) tears. This may explain some of the typical clinical findings, including the prevalence of humeral chondral lesions, after SLAP lesions. The first hypothesis was that SLAP repair could restore the original glenohumeral translation and reduce the increased LHB load after SLAP lesions. The second hypothesis was that SLAP repair after LHB tenotomy could significantly reduce the increased glenohumeral translation.
  
  
  METHODS
  Biomechanical testing was performed on 21 fresh frozen human cadaveric shoulders with an intact shoulder girdle using a sensor-guided industrial robot to apply 20 N of compression in the joint and 50 N translational force at 0°, 30°, and 60° of abduction. LHB loading was measured by a load-cell with 5 N and 25 N preload. Type IIC SLAP lesions were created arthroscopically, and a standardized SLAP repair was done combined with or without LHB tenotomy.
  
  
  RESULTS
  No significant difference of glenohumeral translation and increased LHB load in SLAP repair compared with the intact shoulder was observed under 5 N and 25 LHB preload, except for anterior translation under 25 N LHB preload. After LHB tenotomy after SLAP lesions, no significant difference of translation was observed with or without SLAP repair.
  
  
  CONCLUSIONS
  SLAP repair without associated LHB tenotomy helps normalize glenohumeral translation and LHB loading. The stabilizing effect of the SLAP complex is dependent on the LHB. After biceps tenotomy, SLAP repair does not affect glenohumeral translation.
authors.affiliation: Department of Orthopaedics, University Hospital of Düsseldorf, Düsseldorf, Germany. th.patzer@web.de
authors.forename: Thilo
authors.initials: T
authors.lastname: Patzer
authors.forename: Peter
authors.initials: P
authors.lastname: Habermeyer
authors.forename: Christof
authors.initials: C
authors.lastname: Hurschler
authors.forename: Evgenij
authors.initials: E
authors.lastname: Bobrowitsch
authors.forename: Mathias
authors.initials: M
authors.lastname: Wellmann
authors.forename: Joern
authors.initials: J
authors.lastname: Kircher
authors.forename: Markus D
authors.initials: MD
authors.lastname: Schofer
mesh_terms: D001182:Arthroscopy; D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology / Q000601:surgery*; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures / Q000379:methods*; D012785:Shoulder Joint / Q000601:surgery; D013708:Tendon Injuries / Q000503:physiopathology / Q000601:surgery*; D013710:Tendons / Q000601:surgery*; D058971:Tenotomy / Q000379:methods*