Does increased topside conformity in modular total knee arthroplasty lead to increased backside wear?
In this retrieval study, more conforming tibial inserts demonstrated more backside-normalized wear than the flatter designs. This suggests that in this modular total knee arthroplasty design, higher articular conformity to address the issues of high bearing contact stress comes at a price: increased torque transmitted to the backside insert-to-tray interface. We suggest further work be undertaken to examine newer insert designs to evaluate if our conclusions hold true with the newer generation locking mechanism, tibial tray finish and polyethylene designs, as more highly conforming tibial inserts are introduced into the market.
Morphine inhibits activator protein 1 activation by a mu opioid receptor pathway coupled to nitric oxide as second messenger. The decrease in CD14 expression caused by morphine may play a role in inhibition of activator protein 1 activation following lipopolysaccharide treatment of phagocytes.