Document Detail

The causes of insert backside wear in total knee arthroplasty.
MedLine Citation:
PMID:  12439265     Owner:  NLM     Status:  MEDLINE    
Wear of the insert backside occurs ostensibly because of micromotion at the undersurface articulation that occurs with loading. When a cyclic axial load was applied to contemporary knee implants, all inserts tested moved 2 to 25 microm in the shear plane relative to the metal backing suggesting that undersurface motion may be inevitable. Variables that increase the forces between the insert and metal backing can worsen relative micromotion and backside wear. Forces at the undersurface articulation, created during physiologic loading, are influenced by insert type, articular design, and surgical technique. Increasing articular insert constraint can cause forces at the main articulation to be resisted and transferred to this and the other interfaces. Designs with a cam post mechanism that force rollback at a certain flexion angle create a significant force in this shear plane. Inserts with highly conforming articular geometries can have a similar affect if used to inhibit anteroposterior or mediolateral motion of the femur on the tibial insert. Component alignment and position, and ligament balance also may influence backside wear as suggested by the great variability of wear patterns seen on like insert retrievals and by kinematic differences observed in fluoroscopic studies of the same implant design. Only by understanding these potential causes of backside motion and subsequent wear, can backside wear be mitigated.
Ray C Wasielewski
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Publication Detail:
Type:  In Vitro; Journal Article    
Journal Detail:
Title:  Clinical orthopaedics and related research     Volume:  -     ISSN:  0009-921X     ISO Abbreviation:  Clin. Orthop. Relat. Res.     Publication Date:  2002 Nov 
Date Detail:
Created Date:  2002-11-19     Completed Date:  2002-12-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0075674     Medline TA:  Clin Orthop Relat Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  232-46     Citation Subset:  AIM; IM    
Ohio State University Hospitals, Columbus, 43214, USA.
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MeSH Terms
Arthroplasty, Replacement, Knee*
Equipment Failure Analysis
Knee Joint / physiology*
Knee Prosthesis*
Prosthesis Design
Prosthesis Failure
Stress, Mechanical
Reg. No./Substance:

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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