Review Question - QID 8264

Adhesive wear occurs when 2 surfaces are forced together under a load experience motion. When the adhesive forces exceed the material strength, material is removed from the weaker material. Adhesive wear is the most common mechanism seen in well-functioning hips. Abrasive wear occurs under 2 modes: two-body and three-body abrasive wear. Two-body abrasive wear occurs when asperites or projections from 1 surface remove material from the opposed articulating surface. This is seen with a roughened or damaged surface such as a scratched femoral head. Three-body wear occurs when a third body particle is interposed between the bearing surfaces and results in removal of material from 1 or both of the articular surfaces. Delamination is a type of surface damage seen with oxidized polyethylene. Delamination is frequently seen in knees as a result of crossing wear patterns and high-contact stresses. Fatigue wear occurs when surface and subsurface cyclic shear stresses or strains in the softer material of an articulation exceed the fatigue limit for that material.