title: Wear performance of large-diameter differential-hardness hip bearings.
abstract: We hypothesized that differential-hardness hard-on-hard bearings would generate less wear debris compared with like-hardness metal-on-metal (M-o-M) bearings. We conducted wear testing on 3 types of large-diameter hard hip bearings: (1) contemporary cast-on-cast ("like" hardness) M-o-M; (2) differential-hardness M-o-M; and (3) differential-hardness ceramic-on-metal. A simulated gait profile ranging from 200 to 2000 N was applied to the bearings at a frequency of 1 Hz for 5 Mc. All bearings were tested in an anatomically inverted position in 90% alpha calf serum. Both differential-hardness bearing systems produced lower run-in wear rates (90%-97%), steady-state wear rate (45%-84%), and total metal wear (68%-88%) compared with the like-hardness bearing system. The ceramic-on-metal bearings exhibited the least wear followed by differential-hardness M-o-M bearings; like-hardness M-o-M bearings exhibited the greatest amount of wear. These findings support our hypothesis that differential-hardness hip bearing systems produce less metallic wear debris than those with like hardness and may result in lower metal ion release in vivo.
authors: Arkansas Specialty Orthopaedics, Little Rock, Arkansas 72205, USA.
authors: C Lowry
authors: CL
authors: Barnes
authors: David
authors: D
authors: DeBoer
authors: R Scott
authors: RS
authors: Corpe
authors: Satya
authors: S
authors: Nambu
authors: Michael
authors: M
authors: Carroll
authors: Irina
authors: I
authors: Timmerman
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D002516:Ceramics; D006244:Hardness; D006622:Hip Prosthesis; D008422:Materials Testing; D008670:Metals; D008855:Microscopy, Electron, Scanning; D011474:Prosthesis Design; D011475:Prosthesis Failure; D013499:Surface Properties
chemical_list: D008670:Metals