Linked Life Data

10220187

Source:http://linkedlifedata.com/resource/pubmed/id/10220187

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1999-6-16
pubmed:abstractText
Clinical and radiographic data for 15 McKee-Farrar hip replacements that had failed because of aseptic loosening (4 stem loosening, 9 cup loosening, and 2 loosening of both components) between 0.6 and 21 years (average, 8.3 years) were compared with 15 hips in which the McKee-Farrar total hip replacement has survived between 21 and 26 years. Hips that loosened were biomechanically disadvantaged compared with those that demonstrated long-term survival. Radiographic evaluation demonstrated that in hips that were revised for aseptic femoral loosening, the offset was decreased by a mean of 1.4, whereas it was increased by a mean of 4.9 mm in the surviving hips (P = .04). Further, in hips revised for aseptic loosening, the center of rotation was medialized by a mean of only 1.4 mm, whereas the center of rotation was medialized by a mean of 6.4 mm in the surviving hips (P = .1). Unfavorable biomechanics results in increased joint reaction forces that could contribute to loosening of these prostheses. Five of 6 McKee-Farrar stems revised for aseptic loosening compared with 7 of 15 surviving stems were in varus (P = .1) and, as a result, had cement mantle defects in zones III and VII. Thus, in the McKee-Farrar, similar to what has been seen in hips with metal-on-plastic bearings, curved stems are associated with varus positioning, cement mantle defects, and loosening. Wear of the metal-on-metal articulation does not appear to be the cause of failure in these cases. Wear could not be detected radiographically. At revision surgery, there was no indication of excessive bearing wear or gross metal staining of periprosthetic tissues. Microscopic analysis of tissue sections demonstrated both metal and polymethylmethacrylate particles of variable size and shape. The variability of the particles suggests that they are likely the result of loosening and that they were not generated by bearing surface wear that could cause loosening. Although it is hoped that improvements in the wear resistance of the bearing will increase survivorship, this experience and analysis of the McKee-Farrar total hip replacement illustrates the importance of the implant design, biomechanics of the reconstruction, and role of surgical implantation technique.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0883-5403
pubmed:author
pubmed:issnType
Print
pubmed:volume
14
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
326-32
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Lessons learned from loosening of the McKee-Farrar metal-on-metal total hip replacement.
pubmed:affiliation
Division of Orthopaedic Surgery, Harbor-UCLA Medical Center, Torrance, California, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't