title: Effect of glenoid implant design on glenohumeral stability: an experimental study.
abstract: BACKGROUND
  Though several glenoid implants were developed over the past years, a high rate of glenoid loosening remains. This complication is linked to the glenohumeral stability, defined as humeral head translation. In an intact shoulder, this concept is ensured by all active and passive elements, particularly the labrum. Two features of a glenoid implant can be adjusted to improve the stability, or, in other words, to decrease the translations: the first is the mismatch, defined as the difference of curvature between the prosthetic head and glenoid; the second is the shape of the glenoid component. Therefore, the objective of this study was to compare the performance of 2 glenoid components (Ceraver, Roissy, France): (1) a standard design and (2) a design named "labrum design" with a superior part simulating the anatomic labrum.
  
  
  METHODS
  An experimental device was developed to evaluate forces and kinematics. The device simulated active, dynamic and continuous abduction of an entire arm. It reproduced the Scapulo-Humeral Rhythm. The labrum design was installed first. To evaluate the effect of mismatch on the glenohumeral stability, 3 humeral heads were tested, corresponding to the ones recommended by the company. The experiment was repeated for the standard design.
  
  
  RESULTS
  The results obtained show a general decrease of the prosthetic head translation with the labrum design compared to the standard design. No noticeable effect of mismatch was found.
  
  
  CONCLUSIONS
  A proof of concept of the interest of the artificial labrum was provided since it improved the glenohumeral stability.
authors.affiliation: Laboratoire de recherche en Imagerie et Orthopédie, Centre de recherche, Centre hospitalier de l'Université de Montréal (CHUM), Montréal (QC), Canada. lauranne.sins@gmail.com
authors.forename: Lauranne
authors.initials: L
authors.lastname: Sins
authors.forename: Patrice
authors.initials: P
authors.lastname: Tétreault
authors.forename: Yvan
authors.initials: Y
authors.lastname: Petit
authors.forename: Natalia
authors.initials: N
authors.lastname: Nuño
authors.forename: Fabien
authors.initials: F
authors.lastname: Billuart
authors.forename: Nicola
authors.initials: N
authors.lastname: Hagemeister
mesh_terms: D001178:Arthroplasty; D001696:Biomechanical Phenomena; D002102:Cadaver; D061165:Glenoid Cavity / Q000503:physiopathology*; D006801:Humans; D058430:Humeral Head / Q000033:anatomy & histology / Q000502:physiology*; D007595:Joint Prosthesis; D008422:Materials Testing; D008953:Models, Anatomic; D020959:Polyethylene; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D012540:Scapula; D012785:Shoulder Joint / Q000033:anatomy & histology / Q000502:physiology*
chemical_list: D020959:Polyethylene