title: Glenoid loosening after total shoulder arthroplasty: an in vitro CT-scan study.
abstract: Glenoid fixation failure has only been grossly characterized. This lack of information hinders attempts to improve fixation because of a lack of methodologies for detecting and monitoring fixation failure. Our goal was twofold: to collect detailed data of glenoid fixation fracture, and to investigate computed tomography (CT)-scanning as a tool for investigations of fixation failure. Six cadaver scapulas and six bone-substitute specimens were cyclically loaded and CT-scanned at clinical settings after 0, 1,000, 5,000, 10,000, 30,000, 50,000 and 70,000 load cycles. The fixation status was evaluated by inspection of the scans. After 70,000 cycles, the specimens were sectioned, and the fixation inspected by microscopy. The results of the microscopy analysis were compared to the CT-scan analysis. Fracture of the glenoid fixation initiated at the edge of the glenoid rim and propagated towards and around the keel of the implant. The entire process from initiation to complete fracture took place at the polyethylene implant-cement interface, while the cement, the adjacent bone, and the cement-bone interface remained intact. Thus, strengthening the polyethylene-cement interface should improve glenoid fixation. Microscopy results validated the CT methodology, suggesting that the CT technique is reliable.
authors.affiliation: Department of Orthopaedic Surgery, University Paris Descartes, APHP, European Hospital Georges Pompidou, Paris, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gregory
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hansen
authors.forename: Fabienne
authors.initials: F
authors.lastname: Taillieu
authors.forename: Toby
authors.initials: T
authors.lastname: Baring
authors.forename: Nicolas
authors.initials: N
authors.lastname: Brassart
authors.forename: Céline
authors.initials: C
authors.lastname: Mutchler
authors.forename: Andrew
authors.initials: A
authors.lastname: Amis
authors.forename: Bernard
authors.initials: B
authors.lastname: Augereau
authors.forename: Roger
authors.initials: R
authors.lastname: Emery
mesh_terms: D019643:Arthroplasty, Replacement / Q000009:adverse effects*; D002102:Cadaver; D006801:Humans; D066298:In Vitro Techniques; D011475:Prosthesis Failure; D012783:Shoulder Dislocation / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing