Factors affecting stress shielding and osteolysis after reverse shoulder arthroplasty: A multicenter study in a Japanese population.

BACKGROUND: Stress shielding and osteolysis around the humeral stem after reverse shoulder arthroplasty causes loosening and periprosthetic fractures and reduces bone stock during revision surgery. In Japanese patients, who have relatively small bodies, different characteristics may exist regarding the occurrence of these changes compared with the characteristics of Westerners, who have relatively larger frames. The purpose of this multicenter study was to investigate the incidence and clarify the predictors of stress shielding and osteolysis in Japanese individuals who underwent reverse shoulder arthroplasty. METHODS: The occurrence of stress shielding and osteolysis was investigated in 135 shoulders that had undergone reverse shoulder arthroplasty at least 2 years prior in five Japanese hospitals. During post-surgical follow-up, which was conducted every 3 months, the locations of the stress shielding occurrences, such as cortical thinning and osteopenia (which primarily occurred in zones 1, 2, and 7, where 1 is the greater tuberosity and 7 is the calcar part), spot weld, and condensation lines, were recorded. Cases without any abnormal findings on radiographs obtained up to ≥2 years after surgery were regarded as having no abnormalities. Finally, the predictors of cortical thinning and proximal humeral osteolysis were assessed using univariate and multivariate regression analyses. RESULTS: Cortical thinning and osteopenia occurred in 68 shoulders, a condensation line occurred in 37 shoulders, and spot weld occurred in 23 shoulders. In particular, greater tuberosity and calcar osteolysis occurred in 40 and 47 shoulders, respectively. Long stem, cementless stem, and a larger proximal filling ratio were independent predictors of cortical thinning and osteopenia, whereas a cementless stem, larger metaphysis diameter, and a larger proximal filling ratio were associated with proximal humeral osteolysis. CONCLUSIONS: The predictors of stress shielding and osteolysis included the use of long stems, cementless stems, larger proximal filling ratios, and larger metaphysis diameters. LEVEL OF EVIDENCE: retrospective comparative study (Level III).

Peripheral venous lactate levels substitute arterial lactate levels in the emergency department.

BACKGROUND: Arterial lactate (AL) level is an important predictor of patient prognosis. AL and peripheral venous lactate (PVL) in blood gas analysis have a low concordance rate, and PVL cannot be used as a substitute for AL. However, if the AL range can be predicted from PVL, PVL may be an alternative method for predicting patient prognosis, and the risk of arterial puncture complications with AL may be reduced. This could be a safe and rapid test method. METHODS: This was a retrospective observational study of 125 cases in which blood gas analysis was performed on both arterial and venous blood with an infectious disease in an emergency department. Spearman's rank correlation coefficient (r) and Bland-Altman analyses were performed. Sensitivity, specificity, and area under the curve (AUC) were calculated for PVL to predict AL < 2 mmol/L or < 4 mmol/L. RESULTS: The median [interquartile range] AL and PVL were 1.82 [1.25-2.46] vs. 2.08 [1.57-3.28], respectively, r was 0.93 (p < 0.0001), and a strong correlation was observed; however, Bland-Altman analysis showed disagreement. When AL < 2 mmol/L was used as the outcome, AUC was 0.970, the PVL cutoff value was 2.55 mmol/L, sensitivity was 85.71%, and specificity was 96.05%. If PVL < 2 mmol/L was the outcome, the sensitivity for AL < 2mmol/L was 100%, and for PVL levels ≥ 3 mmol/L, the specificity was 100%. When AL < 4 mmol/L was used as the outcome, AUC was 0.967, the PVL cutoff value was 3.4 mmol/L, sensitivity was 100%, and specificity was 85.84%. When PVL < 3.5 mmol/L was the outcome, the sensitivity for AL < 4 mmol/L was 100%, and for PVL levels ≥ 4 mmol/L, the specificity was 93.81%. CONCLUSIONS: This study revealed that PVL and AL levels in the same critically ill patients did not perfectly agree with each other but were strongly correlated. Furthermore, the high accuracy for predicting AL ranges from PVL levels explains why PVL levels could be used as a substitute for AL level ranges.

Use of near-infrared imaging using indocyanine green associates with the lower incidence of postoperative complications for intestinal and mesenteric injury.

Anastomotic leakage after intestinal resection is one of the most serious complications of surgical intervention for hollow viscus injury. Adequate vascular perfusion of the anastomotic site is essential to prevent anastomotic leakage. Near-infrared imaging using indocyanine green (NIR-ICG) is useful for the objective assessment of vascular perfusion. The aim of this study was to evaluate the association of NIR-ICG with intestinal and mesenteric injuries. This was a retrospective, single-center study of patients undergoing surgery for intestinal and mesenteric injuries. NIR-ICG was used to evaluate vascular perfusion. Postoperative complications were assessed between NIR-ICG and non-NIR-ICG groups.The use of NIR-ICG was associated with a lower incidence of Clavien-Dindo grade ≥ III complications with a statistical tendency (p = 0.076). When limited to patients that underwent intestinal resection, the use of NIR-ICG was significantly associated with a lower risk of perioperative complications (p = 0.009). The use of NIR-ICG tended to associate with the lower incidence of postoperative complications after intestinal and mesenteric trauma surgery. NIR-ICG was associated with a significantly lower risk of complications in patients undergoing intestinal resection. The NIR-ICG procedure is simple and quick and is expected to be useful for intestinal and mesenteric trauma.

Left subclavian and right femoral vein thrombosis in a pregnant patient with antithrombin deficiency.

Pregnancy is well-known risk factor for deep vein thrombosis (DVT), which usually occurs during the third trimester and in the left-sided lower extremity. We present a case of left subclavian and right femoral vein thrombosis in a pregnant woman with a gestational age of 10 weeks. A 39-year-old woman visited the emergency department complaining of acute pain and swelling of the left upper arm and right lower extremity. She showed swelling of the left upper arm and right lower extremity and a low antithrombin level of 40%. Ultrasound examination showed right femoral and left subclavian vein thrombosis. Her DVTs were treated with unfractionated heparin. Five months later, she received a cesarean delivery with intravenous unfractionated heparin and antithrombin replacement to prevent DVT, and she successfully gave birth. A genetic test for antithrombin deficiency confirmed hereditary antithrombin deficiency. DVT during pregnancy can occur in an upper extremity and at multiple sites. An undiagnosed coagulation disorder magnifies the risk of DVT in pregnant patients. We should examine all extremities for which there are complaints of pain and swelling with suspicion of DVT and consecutively search for an underlying coagulation disorder in pregnant patients with unusual clinical features of DVT. .

Selective sorting of polymers with different terminal groups using metal-organic frameworks.

Separation of high-molecular-weight polymers differing just by one monomeric unit remains a challenging task. Here, we describe a protocol using metal-organic frameworks (MOFs) for the efficient separation and purification of mixtures of polymers that differ only by their terminal groups. In this process, polymer chains are inserted by threading one of their extremities through a series of MOF nanowindows. Selected termini can be adjusted by tuning the MOF structure, and the insertion methodology. Accordingly, MOFs with permanently opened pores allow for the complete separation of poly(ethylene glycol) (PEG) based on steric hindrance of the terminal groups. Excellent separation is achieved, even for high molecular weights (20 kDa). Furthermore, the dynamic character of a flexible MOF is used to separate PEG mixtures with very similar terminal moieties, such as OH, OMe, and OEt, as the slight difference of polarity in these groups significantly changes the pore opening kinetics.

Semiquantitative FMO Analysis of Substituent Effect on the Reaction of Permanganate Ion with Unsymmetrical Alkenes.

The substituent effects on the reactions of permanganate ion with unsymmetrical alkenes are analyzed on the assumption of a concerted (3 + 2) cycloaddition model by using an equation obtained by approximation based on the FMO theory in which development and localization of the frontier molecular orbitals at the reaction sites with progress of the reaction are considered. The Hammett plots are successfully reproduced with the newly obtained rate data for the reactions of trans-chalcone and its derivatives and the data for methyl cinnamates, cinnamate ions, and alkyl vinyl ethers taken from the literature using FMO energies and orbital coefficients calculated by the PM3 method. It was indicated that a factor introduced to the basic equation in order to estimate the extent of localization of the molecular orbitals at the transition state is closely related to the position of the transition state along the reaction path.