title: Arm lengthening after reverse shoulder arthroplasty: a review.
abstract: OBJECTIVE
  The purpose of this review is to provide a better understanding of biomechanical changes induced by reverse shoulder arthroplasty (RSA), discuss the different techniques of radiographic assessment of upper limb lengthening after RSA and determine the ideal soft tissue tension that provides the best functional outcome without increasing the risk of complications.
  
  
  METHODS
  Inclusion criteria were articles in which the primary interest was the technique of measuring upper-extremity lengthening after complications related to lengthening and its role in postoperative function; those written in English, French or German; and those that provided evidence levels I-IV relevant to search terms.
  
  
  RESULTS
  Seven articles met our inclusion criteria. Postoperatively, changes in humeral length varied from minus five to five millimetres, and changes in upper-extremity length varied from 15 mm to 27 mm. The acromiohumeral distance averaged 23 mm. Humeral and arm shortening increased the risk of dislocation and led to poor anterior active elevation. The type of surgical approach did not play a role in postoperative function. Subclinical neurological lesions were frequent.
  
  
  CONCLUSIONS
  Studies in this systematic review indicate that deltoid tensioning by restoring humeral length and increasing the acromiohumeral distance is critical for adequate postoperative function and to prevent dislocation. Excessive arm lengthening should be avoided, with zero to two centimetres of lengthening being a reasonable goal to avoid postoperative neurological impairment.
authors.affiliation: Division of Orthopaedics and Trauma Surgery, La Tour Hospital, Rue J.-D. Maillard 3, 1217, Meyrin, Switzerland, alexandre.laedermann@latour.ch.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Lädermann
authors.forename: Tom Bradley
authors.initials: TB
authors.lastname: Edwards
authors.forename: Gilles
authors.initials: G
authors.lastname: Walch
mesh_terms: D019643:Arthroplasty, Replacement / Q000379:methods*; D001696:Biomechanical Phenomena; D001852:Bone Lengthening; D006801:Humans; D006811:Humerus / Q000601:surgery*; D012785:Shoulder Joint / Q000601:surgery*