Clinical suspicion is key: an unusual presentation of septic arthritis after distal pancreatectomy.

Septic arthritis is the result of an infectious agent gaining access a sterile joint. This results in a devastating inflammatory response that leads to rapid destruction of intra-articular cartilage and with it significant morbidity. This case study reports an unusual presentation of septic arthritis following abdominal surgery; specifically, a distal pancreatectomy performed for an enlarged, mid-body pancreas mass involving the splenic artery. This is the first reported case of septic arthritis following abdominal surgery, though the exact etiology is unknown.

Changes in femoral bone mineral density after total knee arthroplasty: a systematic review and meta-analysis.

BACKGROUND: Bone loss after total knee arthroplasty (TKA) may lead to periprosthetic fractures that are associated with significant costs (morbidity, economic, etc.) and pose a challenge to operative fixation. This meta-analysis quantifies the change in bone mineral density (BMD) of the distal femur after primary TKA. METHODS: A systematic review of six databases was performed by two independent reviewers. Studies that reported bone density after knee arthroplasty were identified and inclusion/exclusion criteria was applied. Data were extracted and analyzed using the Comprehensive Meta-Analysis Software. RESULTS: Fourteen studies were included in the analysis. The average decrease in BMD was 0.09 [0.05, 0.13], 0.14 [0.08, 0.20], 0.16 [0.10, 0.23], and 0.16 [0.12, 0.20] g/cm2 at 3, 6, 12, and 24 months, respectively, corresponding to a 9.3%, 13.2%, 15.8%, and 15.4% BMD loss. A high degree of heterogeneity existed between the studies (I2 > 90% at most time points). CONCLUSION: In summary, there is a rapid and significant 15% decrease in BMD in the first 6 months after TKA that is sustained to 24 months. Better understanding regarding how perioperative optimization of bone health may affect BMD loss and the incidence of periprosthetic fracture is essential. LEVEL OF EVIDENCE: Therapeutic Level II.

Intrinsic site-selectivity of ubiquitin dimer formation.

The post-translational modification of proteins with ubiquitin can take on many forms, including the decoration of substrates with polymeric ubiquitin chains. These chains are linked through one of the seven lysine residues in ubiquitin, with the potential to form a panoply of linkage combinations as the chain length increases. The ensuing structural diversity of modifications serves a variety of signaling functions. Still, some linkages are present at a much higher level than others in cellulo. Although ubiquitination is an enzyme-catalyzed process, the large disparity of abundancies led us to the hypothesis that some linkages might be intrinsically faster to form than others, perhaps directing the course of enzyme evolution. Herein, we assess the kinetics of ubiquitin dimer formation in an enzyme-free system by measuring the rate constants for thiol-disulfide interchange between appropriate ubiquitin variants. Remarkably, we find that the kinetically expedient linkages correlate with those that are most abundant in cellulo. As the abundant linkages also appear to function more broadly in cellulo, this correlation suggests that the more accessible chains were selected for global roles.