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Patterns of Loosening of Polyethylene Keeled Glenoid Components After Shoulder Arthroplasty for Primary Osteoarthritis: Results of a Multicenter Study with More Than Five Years of Follow-up

Walch, Gilles MD; Young, Allan A. MD; Boileau, Pascal MD; Loew, Markus MD; Gazielly, Dominique MD; Molé, Daniel MD

Journal of Bone & Joint Surgery - American Volume: 18 January 2012 - Volume 94 - Issue 2 - p 145–150
doi: 10.2106/JBJS.J.00699
Scientific Articles

Background: The aim of this study was to radiographically analyze the long-term glenoid migration patterns following total shoulder arthroplasty to better understand the factors responsible for loosening.

Methods: Complete radiographic follow-up of more than five years was available for 518 total shoulder arthroplasties performed for primary glenohumeral osteoarthritis with use of an anatomically designed prosthesis with a cemented, all-polyethylene, keeled glenoid component. Radiographs were assessed for humeral head subluxation, periprosthetic radiolucent lines, and shifting of the position of the glenoid component. The type of migration of the glenoid was defined according to the direction of tilt, or as subsidence in the case of medial migration.

Results: Definite radiographic evidence of glenoid loosening was observed in 166 shoulders (32%) and was characterized by radiolucency of ≥2 mm over the entire bone-cement interface in thirty shoulders and by a migration of the glenoid component (shift or subsidence) in 136 shoulders. Three predominant patterns of migration of the glenoid component were observed: superior tilting in fifty-two shoulders (10%), subsidence in forty-one shoulders (7.9%), and posterior tilting in thirty-three shoulders (6.4%). Superior tilting of the glenoid was associated with three risk factors: low positioning of the glenoid component, superior tilt of the glenoid component on the immediate postoperative coronal plane radiographs, and superior subluxation of the humeral head (p < 0.05 for all). Subsidence of the glenoid component was associated with the use of reaming to optimize the seating and positioning of the glenoid component (p < 0.001). Posterior tilting of the glenoid component was associated with preoperative posterior subluxation (i.e., a Walch type-B glenoid) and with excessive reaming (p < 0.01 for both).

Conclusions: The three patterns of migration observed in this study underscore the potential importance of the supporting bone beneath the glenoid component. In some shoulders, use of a keel or pegs to provide fixation of a polyethylene component in the absence of good support from subchondral bone may not be sufficient to resist compressive and eccentric forces, resulting in loosening. Preserving subchondral bone may be important for long-term longevity of the glenoid component.

Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

1Centre Orthopédique Santy, 24 Avenue Paul Santy, F-69008 Lyon, France. E-mail address: walch.gilles@wanadoo.fr

2Sydney Shoulder Specialists, Level 2, 156 Pacific Highway, St. Leonards 2065, New South Wales, Australia

3Department of Orthopaedic Surgery and Sports Traumatology, Hôpital de L’Archet II, Medical University of Nice-Sophia Antipolis, 151 Route de St. Antoine de Ginestière, 06202 Nice, France

4University of Heidelberg, Schlierbacher Landstrasse 200a, 69118 Heidelberg, Germany

5Hopitaux Universitaires de Geneve, Service de Chirurgie Orthopédique, Rue Gabrielle Perret-Gentil 4, 1211 Genève 14, Switzerland

6Clinique de Traumatologie, 49 rue Hermite, F-54000 Nancy, France

Copyright 2012 by The Journal of Bone and Joint Surgery, Incorporated
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