title: Biomechanical comparison of acute Hill-Sachs reduction with remplissage to treat complex anterior instability.
abstract: BACKGROUND
  Acute Hill-Sachs reduction represents a potential alternative method to remplissage for the treatment of an engaging Hill-Sachs lesion. This study biomechanically compared the stabilizing effects of an acute Hill-Sachs reduction technique and remplissage.
  
  
  METHODS
  Six cadaveric shoulders were tested. For the acute Hill-Sachs lesion, a unique model was used to create a 30% defect, compressing the subchondral bone while preserving the articular surface. Five scenarios were tested: intact specimen, bipolar lesion, Bankart repair, remplissage with Bankart repair, and Hill-Sachs reduction technique with Bankart repair. The Hill-Sachs lesion was reduced through a lateral cortical window with a bone tamp, and the subchondral void was filled with bone cement.
  
  
  RESULTS
  At 90° of abduction and external rotation (ER), total translation was 11.6 ± 0.9 mm for the bipolar lesion. This was significantly reduced after remplissage (5.9 ± 1.1 mm; P < .001) and after Hill-Sachs reduction (4.7 ± 0.4 mm; P < .001). Compared with an isolated Bankart repair, the average ER loss after remplissage was 4° ± 4° (P = .65), and the average ER loss after Hill-Sachs reduction was 1° ± 3° (P = .99). Similar joint stability was conferred after both procedures, with minimal change in range of motion.
  
  
  CONCLUSIONS
  Remplissage may still be the best way to address chronic Hill-Sachs lesions; however, the reduction technique is a more anatomic alternative and may be a potential option for treating an acutely engaging Hill-Sachs lesion.
authors.affiliation: Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, NY, USA.
authors.forename: Grant H
authors.initials: GH
authors.lastname: Garcia
authors.affiliation: Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, NY, USA.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Degen
authors.affiliation: Orthopaedic Biomechanics Laboratory, Long Beach Veterans Affairs Healthcare System, Long Beach, CA, USA; Department of Orthopaedic Surgery, University of California, Irvine, Orange, CA, USA.
authors.forename: Christopher N H
authors.initials: CNH
authors.lastname: Bui
authors.affiliation: Orthopaedic Biomechanics Laboratory, Long Beach Veterans Affairs Healthcare System, Long Beach, CA, USA.
authors.forename: Michelle H
authors.initials: MH
authors.lastname: McGarry
authors.affiliation: Orthopaedic Biomechanics Laboratory, Long Beach Veterans Affairs Healthcare System, Long Beach, CA, USA; Department of Orthopaedic Surgery, University of California, Irvine, Orange, CA, USA. Electronic address: tqlee@med.va.gov.
authors.forename: Thay Q
authors.initials: TQ
authors.lastname: Lee
authors.affiliation: Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, NY, USA.
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Dines
mesh_terms: D000208:Acute Disease; D000368:Aged; D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D012785:Shoulder Joint / Q000503:physiopathology / Q000601:surgery*
keywords: Hill-Sachs; anatomic reduction; bipolar lesion; bone loss; cadaveric study; instability; remplissage