title: Augmented wedge-shaped glenoid component for the correction of glenoid retroversion: a finite element analysis.
abstract: BACKGROUND
  This study undertook a computational analysis of a wedged glenoid component for correction of retroverted glenoid arthritic deformity to determine whether a wedge-shaped glenoid component design with a built-in correction for version reduces excessive stresses in the implant, cement, and glenoid bone. Recommendations for correcting retroversion deformity are asymmetric reaming of the anterior glenoid, bone grafting of the posterior glenoid, or a glenoid component with posterior augmentation. Eccentric reaming has the disadvantages of removing normal bone, reducing structural support for the glenoid component, and increasing the risk of bone perforation by the fixation pegs. Bone grafting to correct retroverted deformity does not consistently generate successful results.
  
  
  METHODS
  Finite element models of 2 scapulae models representing a normal and an arthritic retroverted glenoid were implanted with a standard glenoid component (in retroversion or neutral alignment) or a wedged component. Glenohumeral forces representing in vivo loading were applied and stresses and strains computed in the bone, cement, and glenoid component.
  
  
  RESULTS
  The retroverted glenoid components generated the highest compressive stresses and decreased cyclic fatigue life predictions for trabecular bone. Correction of retroversion by the wedged glenoid component significantly decreased stresses and predicted greater bone fatigue life. The cement volume estimated to survive 10 million cycles was the lowest for the retroverted components and the highest for neutrally implanted glenoid components and for wedged components.
  
  
  CONCLUSIONS
  A wedged glenoid implant is a viable option to correct severe arthritic retroversion, reducing the need for eccentric reaming and the risk for implant failure.
authors.affiliation: Shiley Center for Orthopaedic Research and Education at Scripps Clinic, La Jolla, CA, USA.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Hermida
authors.affiliation: Shiley Center for Orthopaedic Research and Education at Scripps Clinic, La Jolla, CA, USA.
authors.forename: Cesar
authors.initials: C
authors.lastname: Flores-Hernandez
authors.affiliation: Division of Orthopaedic Surgery, Scripps Clinic, La Jolla, CA, USA.
authors.forename: Heinz R
authors.initials: HR
authors.lastname: Hoenecke
authors.affiliation: Shiley Center for Orthopaedic Research and Education at Scripps Clinic, La Jolla, CA, USA. Electronic address: ddlima@scripps.edu.
authors.forename: Darryl D
authors.initials: DD
authors.lastname: D'Lima
mesh_terms: D001168:Arthritis / Q000150:complications; D019643:Arthroplasty, Replacement / Q000379:methods; D001843:Bone Cements; D060751:Bone Retroversion / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D003198:Computer Simulation; D020342:Finite Element Analysis; D061165:Glenoid Cavity / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D016916:Joint Deformities, Acquired / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D007595:Joint Prosthesis; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D019736:Prostheses and Implants; D011859:Radiography; D012016:Reference Values; D013312:Stress, Physiological
chemical_list: D001843:Bone Cements
keywords: Shoulder arthroplasty; computer model; custom prosthesis; finite element analysis; glenohumeral arthritis; glenoid version; wedged glenoid