Document Detail

Optimal screw placement for base plate fixation in reverse total shoulder arthroplasty.
MedLine Citation:
PMID:  20926311     Owner:  NLM     Status:  In-Data-Review    
HYPOTHESIS: Scapular cortical thickness has not been fully characterized from the perspective of determining optimal screw placement for securing the glenoid base plate in reverse shoulder arthroplasty.
MATERIALS AND METHODS: Twelve fresh frozen cadaveric scapulae underwent high resolution CT scans with 3-dimensional reconstructions and wall thickness analysis. Digital base plates were positioned and virtual screws were placed according to 2 scenarios: A - intraosseous through the entire course and exits a "safe region" with no known neurovascular structures; B - may leave and re-enter the bone and penetrates the thickest cortical region accessible regardless of adjacent structures.
RESULTS: For scenario A, the optimal screw configurations were: (superior screw) length = 35 mm, 9° superior, 2° posterior; (inferior screw-A) length = 34 mm, 16° inferior, 5° anterior; (inferior screw-B) length = 31 mm, 31 inferior, 4 posterior; (posterior screw) length 19 mm, 29° inferior, 3° anterior. For scenario B: (superior screw) length = 36 mm, 28° superior, 10° anterior; (inferior screw) length = 35 mm, 19° inferior, 4° anterior; (posterior screw) length 37 mm, 23° superior, 3° anterior. The anterior screw was consistent between scenarios A and B, averaged 29 mm in length and was directed 16° inferior and 14° posterior.
CONCLUSION: Thicker cortical regions were present in the lateral aspect of the suprascapular notch, scapular spine base, anterior/superior aspect of inferior pillar and junction of glenoid neck and scapular spine. Regions with high cortical thickness were accessible for both scenarios except for the posterior screw in scenario A.
James Guido Distefano; Andrew Y Park; Thuc-Quyen D Nguyen; Gerd Diederichs; Jenni M Buckley; William H Montgomery
Publication Detail:
Type:  Journal Article     Date:  2010-10-06
Journal Detail:
Title:  Journal of shoulder and elbow surgery / American Shoulder and Elbow Surgeons ... [et al.]     Volume:  20     ISSN:  1532-6500     ISO Abbreviation:  J Shoulder Elbow Surg     Publication Date:  2011 Mar 
Date Detail:
Created Date:  2011-03-14     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9206499     Medline TA:  J Shoulder Elbow Surg     Country:  United States    
Other Details:
Languages:  eng     Pagination:  467-76     Citation Subset:  IM    
Copyright Information:
Copyright © 2011 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.
Department of Orthopaedic Surgery, St. Mary's Medical Center, San Francisco, CA, USA.
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