title: Does the latissimus dorsi tendon transfer for massive rotator cuff tears remain active postoperatively and restore active external rotation?
abstract: OBJECTIVE
  The purpose of this study is to evaluate the muscle activity with surface electromyography (EMG) and the clinical outcome of the latissimus dorsi transfer. It remains unclear whether the clinical results of the latissimus dorsi transfer for massive posterosuperior rotator cuff tears are achieved either by active muscle contractions or by a passive tenodesis effect of the transfer.
  
  
  METHODS
  Eight patients were evaluated preoperatively and at 1 year (SD, 0.1) after the latissimus dorsi transfer. Clinical evaluation of outcomes included active range of motion, Constant score, and visual analog scale (VAS) for pain and activities of daily living (ADL). Muscle activity was recorded with EMG during directional isometric abduction and adduction tasks.
  
  
  RESULTS
  The external rotation in adduction improved from 23° to 51° (P = .03). The external rotation in abduction improved from 10° to 70° (P = .02). The mean Constant score improved from 39 to 62 postoperatively (P = .01). The VAS for pain at rest improved from 3.3 preoperatively to 0.1 (P = .02). The VAS for ADL improved from 4.9 to 2.3 (P = .05). The transferred latissimus dorsi remained active in all cases, as reflected by increased latissimus dorsi EMG activity during abduction tasks. In addition, the latissimus dorsi EMG activity shifted from preoperative antagonistic co-activation in adduction to synergistic activation in abduction.
  
  
  CONCLUSIONS
  The latissimus dorsi has synergistic muscle activity after transfer. Apart from a tenodesis effect, directional muscle activity seems relevant for improved clinical outcome and pain relief. A specific gain was observed for external rotation in elevated arm positions, a motion essential for ADL tasks.
authors.affiliation: Department of Orthopaedics, Leiden University Medical Center, Leiden, The Netherlands; Laboratory for Kinematics and Neuromechanics, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: j.f.henseler@lumc.nl.
authors.forename: Jan Ferdinand
authors.initials: JF
authors.lastname: Henseler
authors.affiliation: Department of Orthopaedics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Jochem
authors.initials: J
authors.lastname: Nagels
authors.affiliation: Department of Orthopaedics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Rob G H H
authors.initials: RG
authors.lastname: Nelissen
authors.affiliation: Laboratory for Kinematics and Neuromechanics, Leiden University Medical Center, Leiden, The Netherlands; Department of Rehabilitation, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Jurriaan H
authors.initials: JH
authors.lastname: de Groot
mesh_terms: D000368:Aged; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D016059:Range of Motion, Articular; D020127:Recovery of Function; D012399:Rotation; D017006:Rotator Cuff / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D064171:Superficial Back Muscles / Q000503:physiopathology* / Q000601:surgery; D013708:Tendon Injuries / Q000503:physiopathology* / Q000601:surgery*; D013709:Tendon Transfer; D016896:Treatment Outcome
keywords: Rotator cuff tear; electromyography; irreparable; latissimus dorsi; tendon transfer; transplantation