Greater trochanteric preserving hip arthroplasty in the treatment of infantile septic arthritis: long-term results

Background  

Balanced forces around the hip joint are critical for normal development of the hip joint, so it should be considered in every hip reconstructive procedure.     

Free functioning gracilis transplantation for reconstruction of elbow and hand functions in late obstetric brachial plexus palsy

Background: In late obstetric brachial plexus palsy (OBPP), restoration of elbow and hand functions is a difficult challenge. The use of free functioning muscle transplantation in late OBPP was very scarcely reported. In this study, we present our experience on the use of free functioning gracilis transfer for restoration of elbow and hand functions in late cases of OBPP. Patients and Methods: Eighteen patients with late OBPP underwent free gracilis transfer for reconstruction of elbow and/or hand functions. The procedure was indicated when there was no evidence of reinnervation on EMG and in the absence of local donors. Average age at surgery was 102.5 months. Patients were evaluated using the British Medical Research Council (MRC) grading system and the Toronto Active Movement Scale. Hand function was evaluated by the Raimondi scoring system. Results: The average follow‐up was 65.8 ± 41.7 months. Contraction of the transferred gracilis started at an average of 4.5 ± 1.03 months. Average range of elbow flexion significantly improved from 30 ± 55.7 to 104 ± 31.6 degrees (P <0.001). Elbow flexion power significantly increased with an average of 3.8 grades (P = 0.000147). Passive elbow range of motion significantly decreased from an average of 147 to 117 degrees (P = 0.003). Active finger flexion significantly improved from 5 ± 8.3 to 63 ± 39.9 degrees (P < 0.001). Finger flexion power significantly increased with an average 2.7 grades (P < 0.001). Only 17% achieved useful hand (grade 3) on Raimondi hand score. Triceps reconstruction resulted in an average of M4 power and 45 degrees elbow extension. Conclusion: Free gracilis transfer may be a useful option for reconstruction of elbow and/or hand functions in late OBPP. © 2015 Wiley Periodicals, Inc. Microsurgery 35:350–355, 2015.     

In Vitro and Computational Thrombosis on Artificial Surfaces With Shear Stress

Implantable devices in direct contact with flowing blood are associated with the risk of thromboembolic events. This study addresses the need to improve our understanding of the thrombosis mechanism and to identify areas on artificial surfaces susceptible to thrombus deposition. Thrombus deposits on artificial blood step transitions are quantified experimentally and compared with shear stress and shear rate distributions using computational fluid dynamics (CFD) models. Larger steps, and negative (expanding) steps result in larger thrombus deposits. Fitting CFD results to experimental deposit locations reveals a specific shear stress threshold of 0.41 Pa or a shear rate threshold of 54 s^?1 using a shear thinning blood viscosity model. Thrombosis will occur below this threshold, which is specific to solvent‐polished polycarbonate surfaces under in vitro coagulation conditions with activated clotting time levels of 200–220 s. The experimental and computational models are valuable tools for thrombosis prediction and assessment that may be used before proceeding to clinical trials and to better understand existing clinical problems with thrombosis.     

Centromedullary pinning of radial neck fractures: length matters!

ABSTRACT:: Centromedullary pinning provides an excellent alternative to open reduction in severely displaced radial neck fractures. It has a low complication rate because it is an extra-articular and minimally invasive technique. The functional results have been shown to be good or excellent in most cases. The technique is described clearly in the literature but has posed us with certain difficulties. We present a useful technical tip on performing centromedullary pinning based on our experience of treating radial neck fractures by this method.     

Synthesis and biologic studies of iodinated (I/I) ethidium

An iodinated (¹²⁵I/¹²⁷I) ethidium derivative (3,8-diamino-5-[6′-(p-iodobenzoylamino)-4′-azahexyl]-6-phenylphenanthridinium chloride hydrochloride) was synthesized and characterized. The labeling yield of the ¹²⁵I-labeled derivative was 75% for carrier-free ¹²⁵I, with a radiochemical purity of 95%. The incubation of iodoethidium with calf thymus DNA resulted in a substantial enhancement of fluorescence yield, indicating the intercalation of this compound into DNA. In the presence of iodoethidium, the nuclei of methanol-treated mammalian cells fluoresced, while those of viable cells did not (since the plasma membrane is impermeable to iodoethidium). When viable cells were incubated with the reduced form of the derivative, ¹²⁵I/¹²⁷I-dihydroethidium traversed the plasma membrane, was oxidized in the cytoplasm, and intercalated into nuclear DNA. Finally, we tested the hypothesis that larger malignant solid tumors, containing a relatively greater percentage of degenerating permeable cells, can be targeted with ¹²⁵I-ethidium. In-vivo studies demonstrated a small but positive correlation (R = 0.72) between tumor volume and the uptake of the derivative. Because of the ubiquitous presence of abnormal permeable cells and necrosis in tumors, our results support the belief that radiolabeled DNA-intercalating or DNA-binding molecules may be of diagnostic and therapeutic value for a variety of solid tumors in humans.     

Natural Convection Heat Transfer in a Porous Cavity with Sinusoidal Temperature Distribution Using Cu/Water Nanofluid: Double MRT Lattice Boltzmann Method

In this study, natural convection flow in a porous cavity with sinusoidal temperature distribution has been analyzed by a new double multi relaxation time (MRT) Lattice Boltzmann method (LBM). We consider a copper/water nanofluid filling a porous cavity. For simulating the temperature and flow fields, D2Q5 and D2Q9 lattices are utilized respectively, and the effects of different Darcy numbers (Da) (0.001-0.1) and various Rayleigh numbers (Ra) ($10^3$-$10^5$) for porosity ($ε$) between 0.4 and 0.9 have been considered. Phase deviation ($θ$) changed from 0 to $π$ and the volume fraction of nanoparticles (Ø) varied from 0 to 6%. The present results show a good agreement with the previous works, thus confirming the reliability the new numerical method proposed in this paper. It is indicated that the heat transfer rate increases at increasing Darcy number, porosity, Rayleigh number, the volume fraction of nanoparticles and phase deviation. However, the most sensitive parameter is the Rayleigh number. The maximum Nusselt deviation is 10%, 32% and 33% for Ra=$10^3$, $10^4$ and $10^5$, respectively, with $ε = 0.4$ to $ε = 0.9$. It can be concluded that the effect of Darcy number on the heat transfer rate increases at increasing Rayleigh number, yielding a maximum enhancement of the average Nusselt number around 12% and 61% for Ra=$10^3$ and Ra=$10^5$, respectively.     

Collagen nerve protector in rat sciatic nerve repair: A morphometric and histological analysis

Peripheral nerve repair is often complicated by fibroblastic scar formation, nerve dysfunction, and traumatic neuroma formation. Use of bio‐absorbable protective wraps may improve outcomes of these repairs. This study histologically compared the incidence of neuroma formation, connective tissue proliferation, and axonal regrowth in transected rat sciatic nerves repaired with and without tubular collagen nerve sleeves. Twenty Sprague‐Dawley rats underwent unilateral sharp sciatic nerve transection and microscopic nerve repair with four epineural sutures and were randomly treated with or without an encircling collagen nerve sleeve. Normal nerves from the contralateral sciatic nerve were also examined. At sacrifice three months later, the nerves were evaluated for traumatic neuroma formation, perineural scar formation, and morphometric analysis. Histological examination of normal and repaired nerves by a neuropathologist demonstrated healing, minimal Wallerian degeneration and no traumatic neuroma formation. Distal section analysis (nine nonwrapped, 10 wrapped), revealed no significant differences in total fascicular area, myelinated fibers per nerve, fiber density, myelin area per nerve, myelinated fiber diameter, axon diameter, myelin thickness, or G‐ratio. Significantly greater (P = 0.005) inner epineural connective tissue formation was observed in nonwrapped nerves (0.62 mm² ± 0.2) versus wrapped nerves (0.35 mm² ± 0.16). The ratio of connective tissue to fascicular area was larger in nonwrapped (1.08 ± 0.26) versus wrapped nerves (0.63 ± 0.22) (P < 0.001). This study demonstrated decreased inner epineural connective tissue formation with use of a collagen nerve wrap during primary repair of peripheral nerve transection in a rat sciatic nerve model. © 2010 Wiley‐Liss, Inc. Microsurgery 30:392–396, 2010.     

Improved Fracture Risk Assessment Based on Nonlinear Micro‐Finite Element Simulations From HRpQCT Images at the Distal Radius

More accurate techniques to estimate fracture risk could help reduce the burden of fractures in postmenopausal women. Although micro‐finite element (µFE) simulations allow a direct assessment of bone mechanical performance, in this first clinical study we investigated whether the additional information obtained using geometrically and materially nonlinear µFE simulations allows a better discrimination between fracture cases and controls. We used patient data and high‐resolution peripheral quantitative computed tomography (HRpQCT) measurements from our previous clinical study on fracture risk, which compared 100 postmenopausal women with a distal forearm fracture to 105 controls. Analyzing these data with the nonlinear µFE simulations, the odds ratio (OR) for the factor‐of‐risk (yield load divided by the expected fall load) was marginally higher (1.99; 95% confidence interval [CI], 1.41–2.77) than for the factor‐of‐risk computed from linear µFE (1.89; 95% CI, 1.37–2.69). The yield load and the energy absorbed up to the yield point as computed from nonlinear µFE were highly correlated with the initial stiffness (R² = 0.97 and 0.94, respectively) and could therefore be derived from linear simulations with little loss in precision. However, yield deformation was not related to any other measurement performed and was itself a good predictor of fracture risk (OR, 1.89; 95% CI, 1.39–2.63). Moreover, a combined risk score integrating information on relative bone strength (yield load‐based factor‐of‐risk), bone ductility (yield deformation), and the structural integrity of the bone under critical loads (cortical plastic volume) improved the separation of cases and controls by one‐third (OR, 2.66; 95% CI, 1.84–4.02). We therefore conclude that nonlinear µFE simulations provide important additional information on the risk of distal forearm fractures not accessible from linear µFE nor from other techniques assessing bone microstructure, density, or mass. © 2013 American Society for Bone and Mineral Research.