DBEC: Damage vs. Wear in Knees - An Important Distinction

Retrieved knee devices sent to us by orthopaedic surgeons are assessed for damage, and also assessed for wear quanitatively to the extent possible. Dimensions of retrievals are compared to design specifications to calculate both articular and backside wear. Wear and wear rate are correlated with variables including polyethylene pedigree, articular bearing geometry, and device fixation. An important early outcome from this effort is the distinction between damage and wear of knee bearing inserts.

Damage of joint arthroplasty bearings can be visually striking, can be described semi-quantitatively according to published techniques, and can impact mechanical performance and kinematics of the implant. Wear that occurs by abrasive/adhesive processes can be very challenging to discern and quantify, yet can produce large volumes of small debris particles that can lead to osteolysis. Damage and wear are important but distinct phenomena that can have different impacts on clinical performance.