title: Retrieval analysis of squeaking ceramic implants: are there related specific features?
abstract: BACKGROUND
  Ceramic-on-ceramic total hip arthroplasty is routinely used for young and active patients with end stage of hip osteoarthritis. However, squeaking noise is a recently identified problem with such bearing surface. Many in vivo and in vitro studies have been conducted trying to find the potential causes of this phenomenon. However, we are not aware of any study analyzing retrieved ceramic implants for squeaking.
  
  
  OBJECTIVE
  Our primary hypothesis was that the surface analysis of retrieved ceramic implants with squeaking would present interesting deteriorations that could explain the squeaking noise.
  
  
  METHODS
  Nine retrieved squeaking implants from ceramic-on-ceramic total hip arthroplasty that were retrieved for various reasons (two exclusively for squeaking, four for recurrent dislocation, one for aseptic loosening and two for instability) were analyzed. Implant positioning was calculated, macroscopic damages were noticed and microscopic roughness was analyzed. The retrieved implants were then tested on a hip simulator reproducing flexion/extension motions in several situations in lubricated and non-lubricated conditions in order to reproduce squeaking.
  
  
  RESULTS
  Five cups were considered with borderline insufficient anteversion. Gross impingement damage was visible on seven implants. All the retrieved heads had visible metal transfer on their surface. Eight implants had visible stripe wear. Microscopic analysis showed roughness higher than six microns on the retrieved heads. Squeaking was reproduced in vitro in dry conditions. In lubricated conditions, squeaking did not occur for the retrieved hips.
  
  
  CONCLUSIONS
  This retrieval analysis suggests that problems of cup orientation and design which can lead to impingement can generate lubrication problems because of metal transfer plus/minus stripe wear which is a common theme in ceramic-on-ceramic bearings that squeak.
authors.affiliation: T-Pavilion, Department of Orthopaedic Surgery, Edouard-Herriot Hospital, 5, place d'Arsonval, 69437, Lyon cedex 03, France. christophe.chevillotte@chu-lyon.fr
authors.forename: C
authors.initials: C
authors.lastname: Chevillotte
authors.forename: R T
authors.initials: RT
authors.lastname: Trousdale
authors.forename: K-N
authors.initials: KN
authors.lastname: An
authors.forename: D
authors.initials: D
authors.lastname: Padgett
authors.forename: T
authors.initials: T
authors.lastname: Wright
mesh_terms: D000328:Adult; D000368:Aged; D000537:Aluminum Oxide / Q000737:chemistry*; D019644:Arthroplasty, Replacement, Hip; D002516:Ceramics / Q000737:chemistry*; D019544:Equipment Failure Analysis; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D054327:Lubricants / Q000737:chemistry; D008153:Lubrication; D008297:Male; D008422:Materials Testing / Q000379:methods*; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery; D011474:Prosthesis Design; D011475:Prosthesis Failure; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D054327:Lubricants; D000537:Aluminum Oxide