title: Is there any influence of humeral component retroversion on range of motion and clinical outcome in reverse shoulder arthroplasty? A clinical study.
abstract: OBJECTIVE
  Reverse shoulder arthroplasty becomes more widely used as treatment for patients with complex cuff arthropathy. Theoretically, a higher retroversion of the humeral component leads to an increase in external rotation ROM and a decrease in internal rotation ROM. There is no consensus in optimal retroversion orientation. We retrospectively describe the effect of retroversion of the humeral component. We hypothesize that 20° humeral retroversion improves postoperative ROM, strength or clinical outcome scores compared to neutral retroversion.
  
  
  METHODS
  A retrospective clinical study is performed. An Aequalis reverse shoulder prosthesis was placed in 65 shoulders from 58 patients with a mean age of 73.8 years (95% CI 72.0-75.6). Between October 2006 and May 2012, the humeral component was placed in neutral retroversion in 36 shoulders (55%). From June 2012 to June 2014, it was placed in 20° retroversion in 29 shoulders (45%). After a mean follow-up of 36 months with a minimum of 12 months, patients were invited for a study visit. ROM, strength, Constant-Murley and Oxford Scores were measured.
  
  
  RESULTS
  ROM, strength and Constant-Murley and Oxford Scores did not differ significantly between both groups.
  
  
  CONCLUSIONS
  With the Aequalis prosthesis, no significant effect of 0° or 20° retroversion on external and internal rotation ROM, strength or functional outcome scores was found.
authors.affiliation: Department of Orthopedic Surgery, HagaZiekenhuis, Sportlaan 600, 2566 MJ, The Hague, The Netherlands. frisodeboer@gmail.com.
authors.forename: F A
authors.initials: FA
authors.lastname: de Boer
authors.affiliation: Department of Orthopedic Surgery, HagaZiekenhuis, Sportlaan 600, 2566 MJ, The Hague, The Netherlands.
authors.forename: P M
authors.initials: PM
authors.lastname: van Kampen
authors.affiliation: Department of Orthopedic Surgery, HagaZiekenhuis, Sportlaan 600, 2566 MJ, The Hague, The Netherlands.
authors.forename: P E
authors.initials: PE
authors.lastname: Huijsmans
mesh_terms: D000368:Aged; D019643:Arthroplasty, Replacement / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006811:Humerus / Q000601:surgery; D007595:Joint Prosthesis; D008297:Male; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D000070636:Rotator Cuff Injuries / Q000601:surgery*; D012782:Shoulder / Q000601:surgery; D016896:Treatment Outcome
keywords: Component; Positioning; Prosthesis; Retroversion; Reverse; Shoulder