Background Revision THA and TKA are growing and important clinical and economic challenges. Healthcare systems tend to combine revision joint replacement procedures into a single service line, and differences between revision THA and revision TKA remain incompletely characterized. These differences carry implications for guiding care and resource allocation. We therefore evaluated epidemiologic trends associated with revision THAs and TKAs. Questions/purposes We sought to determine differences in (1) the number of patients undergoing revision TKA and THA and respective demographic trends; (2) differences in the indications for and types of revision TKA and THA; (3) differences in patient severity of illness scoring between THA and TKA; and (4) differences in resource utilization (including cost and length of stay [LOS]) between revision THA and TKA. Methods The Nationwide Inpatient Sample (NIS) was used to evaluate 235,857 revision THAs and 301,718 revision TKAs between October 1, 2005 and December 31, 2010. Patient characteristics, procedure information, and resource utilization were compared across revision THAs and TKAs. A revision burden (ratio of number of revisions to total number of revision and primary surgeries) was calculated for hip and knee procedures. Severity of illness scoring and cost calculations were derived from the NIS. As our study was principally descriptive, statistical analyses generally were not performed; however, owing to the large sample size available to us through this NIS analysis, even small observed differences presented are likely to be highly statistically significant.One or more of the authors (SMK, KO, EL) are employees of Exponent, Inc, Menlo Park, CA, USA, and Philadelphia, PA, USA. One of the authors certifies that he (DJB), or a member of his or her immediate family, has received or may receive payments or benefits, during the study period, an amount in excess of USD 100,001-USD 1,000,000, from DePuy Orthopaedics, Inc (Warsaw, IN, USA). One of the authors (TPV) certifies that he has received or may receive payments or benefits, during the study period, an amount in excess of USD 10,001-USD 100,000 from DePuy Orthopaedics, Inc (Warsaw, IN, USA). One of the authors (HER) certifies that he has received or may receive payments or benefits, during the study period, an amount in excess of USD 100,001-USD 1,000,000, from Zimmer, Inc (Warsaw, IN, USA Clin Orthop Relat Res (2015) 473:2131-2138 DOI 10.1007/s11999-014-4078-8 Clinical Orthopaedics and Related Research ® A Publication of The Association of Bone and Joint Surgeons®Results Revision TKAs increased by 39% (revision burden, 9.1%-9.6%) and THAs increased by 23% (revision burden, 15.4%-14.6%). Revision THAs were performed more often in older patients compared with revision TKAs. Periprosthetic joint infection (25%) and mechanical loosening (19%) were the most common reasons for revision TKA compared with dislocation (22%) and mechanical loosening (20%) for revision THA. Full (all-component) revision was more common i...

Elevated levels of plasma homocysteine (Hcy) correlate with increased risk of cardiovascular and Alzheimer diseases. We studied the effect of elevated Hcy on the blood-brain barrier (BBB) to explore the possibility of a vascular link between the 2 diseases. On a hyperhomocysteinemic diet, cystathionine beta-synthase (Cbs)-heterozygous mice develop hyperhomocysteinemia. Intravital microscopy analysis of the mesenteric venules showed that leukocyte rolling velocity was markedly decreased and numbers of adherent cells were increased in the mutant mice. This was due at least in part to increased expression of P-selectin. BBB permeability was measured by Evans blue dye permeation and was found to be 25% greater in the Cbs(+/-) cortex compared with wild-type controls. Our study suggests an important toxic effect of elevated Hcy on brain microvessels and implicates Hcy in the disruption of the BBB.

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Porous tantalum tibial cones offer a promising management option for severe tibial bone loss. At the intermediate-term follow-up (five to nine years), porous tantalum tibial cones had durable clinical results and radiographic fixation. The biologic ingrowth of these implants offers the potential for successful long-term structural support in complex knee reconstruction.