Surgical Template Fabrication Using Cost-Effective 3D Printers.

PURPOSE: This in vitro study aimed to evaluate the accuracy of surgical templates fabricated using three different 3D printing technologies. MATERIALS AND METHODS: Ten identical surgical templates were printed using four 3D printers (two of an identical make and model). Each of the surgical templates was scanned by a reference scanner and then imported into the inspection software. Inspection software utilized a best-fit alignment to automatically calculate the 3D variation at all points. RESULTS: Statistically significant differences were found among the three groups (χ2[2] = 12.880, P = .0016). Mean 3D deviation was also significantly different between the two printers of an identical make and model (χ2[1] = 8.251, P = .0041). CONCLUSION: All of the tested printers had a high level of accuracy in the fabrication of surgical templates, which would justify the trial of cost-effective printers for clinical fabrication of surgical implant templates.

Particulate and ion forms of cobalt-chromium challenged preosteoblasts promote osteoclastogenesis and osteolysis in a murine model of prosthesis failure.

This study investigated the interactive behavior of the particulate and ion forms of cobalt-chromium (Co-Cr) alloy challenged preosteoblasts during the process of prosthetic implant loosening. Preosteoblasts were challenged with Co-Cr particles or Co(II) ions for 72 h, followed by the proliferation and PCR assays. For in vivo test, a titanium pin was implanted into proximal tibia of SCID mice to mimic knee replacement. Co-Cr particles or Co(II) ion challenged preosteoblasts (5 × 105 ) were intra-articularly injected into the implanted knee. The animals were sacrificed 5 weeks post-op, and the prosthetic knees were harvested for biomechanical pin-pullout testing, histological evaluations, and microCT assessment. In vitro study suggested that Co-Cr particles and Co(II) ions significantly suppressed the proliferation of preosteoblasts in a dose-dependent manner. RT-PCR data on the challenged cells indicated overexpression of receptor activator of nuclear factor kappa-B ligand (RANKL) and inhibited osteoprotegerin (OPG) gene expression. Introduction of the differently challenged preosteoblasts to the pin-implant mouse model resulted in reduced implant interfacial shear strength, thicker peri-implant soft-tissue formation, more TRAP+ cells, lower bone mineral density, and bone volume fraction. In conclusion, both Co-Cr particles and Co(II) ions interfered with the growth, maturation, and functions of preosteoblasts, and provides evidence that the metal ions as well play an important role in effecting preosteoblasts in the pathogenesis of aseptic loosening. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 187-194, 2019.

The Utility of a Syndemic Framework in Understanding Chronic Disease Management Among HIV-Infected and Type 2 Diabetic Men Who Have Sex with Men.

Syndemic theory posits that epidemics of multiple physical and psychosocial problems co-occur among disadvantaged groups due to adverse social conditions. Although sexual minority populations are often stigmatized and vulnerable to multiple health problems, the syndemic perspective has been underutilized in understanding chronic disease. To assess the potential utility of this perspective in understanding the management of co-occurring HIV and Type 2 diabetes, we used linear regression to examine glycemic control (A1c) among men who have sex with men (MSM) with both HIV and Type 2 diabetes (n = 88). Bivariable linear regression explored potential syndemic correlates of inadequate glycemic control. Compared to those with adequate glycemic control (A1c ≤ 7.5 %), more men with inadequate glycemic control (A1c > 7.5 %) had hypertension (70 vs. 46 %, p = 0.034), high triglycerides (93 vs. 61 %, p = 0.002), depression (67 vs. 39 %, p = 0.018), current substance abuse (15 vs. 2 %, p = 0.014), and detectable levels of HIV (i.e., viral load ≥75 copies per ml blood; 30 vs. 10 %, p = 0.019). In multivariable regression controlling for age, the factors that were independently associated with higher A1c were high triglycerides, substance use, and detectable HIV viral load, suggesting that chronic disease management among MSM is complex and challenging for patients and providers. Findings also suggest that syndemic theory can be a clarifying lens for understanding chronic disease management among sexual minority stigmatized populations. Interventions targeting single conditions may be inadequate when multiple conditions co-occur; thus, research using a syndemic framework may be helpful in identifying intervention strategies that target multiple co-occurring conditions.