Postmortem Retrieval Analysis of Metallosis and Periprosthetic Tissue Metal Concentrations in Total Knee Arthroplasty.

Background: The purpose of this study is to determine the preferred sampling location for tissue analysis in total knee arthroplasty (TKA) and to evaluate metal concentrations, inflammatory cytokines, component damage, and tissue metallosis.

Methods: Twenty TKA systems were collected at necropsy along with tissue samples from 5 distinct locations. Inductively coupled plasma mass spectrometry (ICP-MS) analysis was performed to determine cobalt (Co), chromium (Cr), and titanium (Ti) concentrations.

Is Soft Tissue Laxity Associated with Tissue Metal Concentrations after Total Knee Arthroplasty?

Increased joint laxity is associated with excessive polyethylene wear, but the correlation between laxity and metal wear has not been established. Fifteen necropsy-retrieved primary total knee replacements were mounted into a custom knee-testing machine that measured anterior-posterior, varus-valgus, and internal-external rotational laxity at 0°, 30°, 60°, and 90° of flexion. Inductively coupled plasma-mass spectrometry analysis was performed to measure the cobalt (Co), chromium (Cr), and titanium (Ti) concentrations in periprosthetic tissue samples.

Total Knee Post-Cam Design Variations and Their Effects on Kinematics and Wear Patterns.

Post-cam designs for posterior-stabilized total knee arthroplasy (TKA) implants have evolved over the last 2 decades. These designs have evolved from symmetric post and cam to asymmetric designs that include anterior post interactions to affect a kinematic change in full extension. All design changes have consequences on the resulting femorotibial contact kinematics and, depending on the amount of constraint built into the design, these changes may have significant consequences on the wear patterns on the tibial polyethylene insert.