Trends in total knee arthroplasty implant utilization.

The incidence of total knee arthroplasty (TKA) has increased alongside our knowledge of knee physiology, kinematics, and technology resulting in an evolution of TKA implants. This study examines the trends in TKA implant utilization. Data was extracted from The Orthopedic Research Network to evaluate trends in level of constraint, fixed vs. mobile bearing, fixation, and type of polyethylene in primary TKAs. In 2012, 88% used cemented femoral and tibial implants, and 96% involved patellar resurfacing. 38% of implants were cruciate retaining, 53% posterior stabilized or condylar stabilized, 3% constrained. 91% were fixed-bearing, 7% mobile-bearing. 52% of tibial inserts were HXLPE. TKA implant trends demonstrate a preference for cemented femoral and tibial components, patellar resurfacing, fixed-bearing constructs, metal-backed tibial components, patellar resurfacing, and increased usage of HXLPE liners.

Trends in total hip arthroplasty implant utilization in the United States.

Total hip arthroplasty (THA) implant usage has evolved as experience has been gained with newer implant designs. The purpose of this study was to characterize trends in THA implant usage between 2001 and 2012. The Orthopedic Research Network, which includes 174 hospitals and ~105,000 THA, was used to evaluate trends in fixation, bearings, acetabular cup and liner, and femoral head usage. In 2012, 93% of THAs were cementless; 56% of THA bearings were metal-HXLPE; and 35% were ceramic-HXLPE. 99% of acetabular cups were modular. 61% of femoral heads were metal, 39% were ceramic, 51% were 36mm, and 28% were 32mm. THA implant usage trends favor cementless fixation, metal-on-polyethylene or ceramic-on-polyethylene bearings, modular acetabular cups, and large diameter femoral heads.

Impaired lymphocyte reactivity measured by immune function testing in untransplanted patients with cirrhosis.

The immune function test is an integrated measure of total mitogen-inducible CD4(+) T cell metabolic activity in the peripheral blood, and it is used to guide the dosing of immunosuppressive medications after solid organ transplantation. Recently, low CD4(+) T cell metabolic activity due to pharmacologic immunosuppression has been linked to rapidly progressive cirrhosis in hepatitis C virus (HCV)-infected liver transplant recipients. We speculate that either cirrhosis or HCV might adversely affect the CD4(+) T cell reactivity even in the absence of immunosuppressive medications. We thus performed this assay on a cohort of untransplanted hepatology patients who were not taking immunomodulatory drugs. Low mitogen-stimulated CD4(+) T cell metabolic reactivity was more commonly seen in untransplanted patients with HCV cirrhosis or with cirrhosis due to other causes but not in control patients or in those with chronic HCV in the absence of cirrhosis. The lowest mean CD4(+) T cell reactivities were seen in patients with both cirrhosis and HCV. Caution should be exercised when immune function test results are used to guide immunomodulatory therapy in transplant recipients with suspected cirrhosis, as low immune function test results may be a consequence of hepatic cirrhosis or of pharmacologic immunosuppression.