title: Association of third body embedment with rim damage in retrieved acetabular liners.
abstract: Third-body effects are a major cause of the substantial variability of wear in total hip replacements. One potential mechanism by which third-body debris can access wear-critical central regions of closely conforming metal-on-polyethylene bearing couples is by fluid convection during incidents of subluxation accompanying neck-on-liner impingement. To provide evidence for this premise, we determined the association of severity of liner rim indentation damage (indicative of impingement frequency/vigor) and the presence of embedded third-body debris in 194 implants retrieved at revision. Rim damage was graded using the five-point Hospital for Special Surgery scale. Particle embedment was assessed both manually and by means of an image analysis computer program that detected the composition, size, and location of each particle. Sixty-eight percent of the cups showed rim indentation damage. We found an association between severity of rim damage and presence of embedded debris. There was substantial nonuniformity of the spatial distribution of the embedded debris, with the predominance of embedded debris at intermediate latitudes. These findings support the premise of convection of debris-laden joint fluid during lever-out subluxation as a mechanism for wear-consequential third-body particles to gain access to highly loaded regions of the bearing surface, thus potentiating increased wear.
authors: Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, IA 52242, USA.
authors: Hannah J
authors: HJ
authors: Lundberg
authors: Steve S
authors: SS
authors: Liu
authors: John J
authors: JJ
authors: Callaghan
authors: Douglas R
authors: DR
authors: Pedersen
authors: Michael R
authors: MR
authors: O'Rourke
authors: Devon D
authors: DD
authors: Goetz
authors: David A
authors: DA
authors: Vittetoe
authors: John C
authors: JC
authors: Clohisy
authors: Thomas D
authors: TD
authors: Brown
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation*; D020878:Device Removal; D019544:Equipment Failure Analysis; D006621:Hip Joint / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D004204:Joint Dislocations / Q000503:physiopathology*; D007593:Joint Instability; D008670:Metals / Q000737:chemistry*; D010014:Osteolysis / Q000209:etiology; D010316:Particle Size; D020959:Polyethylene / Q000737:chemistry*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D013314:Stress, Mechanical; D013499:Surface Properties; D013582:Synovial Fluid / Q000737:chemistry; D016896:Treatment Outcome; D016474:Weight-Bearing
chemical_list: D008670:Metals; D020959:Polyethylene