The “floating ulna” injury in adults: a case report, literature review and proposed injury classification

Background Ipsilateral Galeazzi fracture with elbow dislocation, namely the “floating ulna” injury, is a rare injury pattern. A few reports have described this type of injury and its treatment. Case presentation A 33-year-old female at 38+ weeks gestational age presented with Galeazzi fracture and posterolateral elbow dislocation of the left upper extremity. The patient was treated with closed reduction of the elbow, open reduction, and internal fixation of the radial shaft fracture with a dynamic compression plate and K-wire stabilization of the unstable distal radioulnar joint. At the 12-month follow-up, the patient had no pain or signs of instability. Range of motion was 0–135° at the elbow, 70° extension and 80° flexion at the wrist, and 80° supination and 80° pronation at the forearm. Conclusion The “floating ulna” injury is a rare and special injury pattern with ipsilateral Galeazzi fracture and elbow dislocation. This type of injury was likely caused by significant amount of deforming force and the unique position of upper limb when the patient fell from a height of 1–2 m in high-energy trauma.

A comparison between the presence and absence of virtual viscosity in the behaviour of the two phase flow interface

In this paper, a numerical study is performed in order to investigate the effect of the virtual viscosity on simulation of separated two-phase flow of gas-liquid. The governing equations solved by shock capturing method which can provide predicting the interface without the flow field solving. In this work, in order to calculate the numerical flux term, first-order centred scheme (Force scheme) was applied cause of its accuracy and appropriate validation. Analysis approves that the obtained stability range of this research is consistent with the classic Kelvin-Helmholtz instability equation only for the long wavelength with small amplitude. Results reveal that when the wavelengths are reduced, the specified range is not consistent and wavelength affects on instability range and it is over predicted. An algorithm for water faucet problem was developed in Fortran language. Short wavelength perturbations induce unbounded growth rates and make it impossible to achieve converging solutions. The approach taken in this article has been to adding virtual viscosity as a CFD technique, is used to remedy this deficiency.

Axially symmetric shear-free fluids in f(R,T) gravity

In this work, we have discussed the implications of shear-free condition on axially symmetric anisotropic gravitating objects in [Formula: see text] theory. Restricted axial symmetry ignoring rotation and reflection entries containing three independent metric functions is taken into account for establishment of instability range. Implementation of linear perturbation on constitutive modified dynamical equations yield evolution equation. This equation associates adiabatic index [Formula: see text] with material and dark source components of physical parameters defining stable and unstable regions in Newtonian (N) and post-Newtonian (pN) approximations. It is remarked that the axial system evolving under shear-free condition implicates high levels of stability in anisotropic environment.

High tibial osteotomy in varus knees: indications and limits

Opening wedge high tibial osteotomy (OWHTO) is a surgical procedure that aims to correct the weight-bearing axis of the knee, moving the loads laterally from the medial compartment. Conventional indications for OWHTO are medial compartment osteoarthritis and varus malalignment of the knee; recently OWHTO has been used successfully in the treatment of double and triple varus. OWHTO, in contrast to closing wedge high tibial osteotomy, does not require fibular osteotomy or peroneal nerve dissection, or lead to disruption of the proximal tibiofibular joint and bone stock loss. For these reasons, interest in this procedure has grown in recent years.The aim of this study is to review the literature on OWHTO, considering indications and prognostic factors (body mass index, grade of osteoarthritis, instability, range of movement and age), outcomes at midterm follow-up, and limits of the procedure (slope modifications, patellar height changes and difficulties in conversion to a total knee arthroplasty).

Effects of some physical factors on the stability of collapsing stars

This paper formulates the instability regions of a general charged spherically symmetric matter distribution with anisotropic pressure, shear viscosity, radiation density and radial heat flux. Matching conditions are found by taking Reissner–Nordström–Vaidya spacetime as an exterior geometry. The perturbed forms of Einstein–Maxwell field equations and conservation laws are constructed to formulate the collapse equation. The instability regions are identified under N and pN limits for the stability analysis. We conclude that the adiabatic index identifies the instability range which depends upon physical parameters like anisotropic pressure, energy density, shear viscosity and electromagnetic field and heat flux but radiation density has no role.

BIFURCATIONS AND CHAOS OF AN AXIALLY MOVING PLATE UNDER EXTERNAL AND PARAMETRIC EXCITATIONS

The chaos and bifurcations in transverse motion of an axially moving thin plate under external and parametric excitations are studied herein. The geometric nonlinearity is introduced by using the von Karman large deflection theory. The coupled partial differential equations of transverse deflection and stress are truncated into a set of ordinary differential equations. By using the Poincaré map and the largest Lyapunov exponent, the dynamical behaviors including chaos are identified based on numerical solutions of the ordinary differential equations. The bifurcation diagrams are presented for different parameters, such as axially moving velocity, damping, external and parametric excitation amplitudes. The chaos is detected in both cases of external and parametric excitations. The interesting relevance between onset of chaos with the corresponding linear instability range are indicated in the external and parametric responses.

Peroneal Tendon Subluxation in Athletes: Fibular Groove Deepening and Retinacular Reconstruction

Background: The purpose of this study was to evaluate the results of operative treatment of recurrent peroneal tendon dislocations followed by accelerated rehabilitation incorporating early range of motion and intermittent immobilization. Methods: Four female and nine male athletes with an average age of 24 years had objective clinical evidence of peroneal tendon dislocation (14 ankles). Operative treatment involved removing a bone flap from the distal posterior fibula, deepening the posterior fibular groove, and reattaching the bone flap within the deepened groove. The superior peroneal retinaculum also was reconstructed. Postoperatively, a removable boot was worn for approximately 4 weeks, when it was replaced with a stirrup brace. Results: At an average followup of 35 months, no recurrent subluxation or dislocation of the peroneal tendons had occurred. All patients were able to return to sports by 3 months after surgery. Nine of the 14 ankles regained normal range of motion, and the remaining five were within 5 degrees of the opposite side. Four patients were completely pain free, and nine patients had mild occasional pain that did not limit their activities. Eight patients returned to preinjury sports participation, and five patients elected to participate in sports at a level lower than they had before surgery for reasons not related to their ankle injury. Conclusions: This procedure was reliable for preventing recurrent peroneal tendon instability. Range of motion was nearly normal, immobilization time was minimal, and all patients returned to daily activities and sports within 3 months of surgery.

Stability of solitary-wave solutions to a modified Zakharov–Kuznetsov equation

In the context of ion-acoustic waves in a magnetized plasma comprising cold ions and non-isothermal electrons, small-amplitude, weakly nonlinear waves have been shown previously by Munro and Parkes to be governed by a modified version of the Zakharov–Kuznetsov equation. In this paper, we consider solitary travelling-wave solutions to this equation that propagate along the magnetic field. We investigate the initial growth rate γ(k) of a small transverse sinusoidal perturbation of wavenumber k. The instability range is shown to be 0 < k < 3. We use the multiple-scale perturbation method developed by Allen and Rowlands to determine a consistent expansion of γ about k = 0 and k = 3. By combining these results in the form of a Padé approximant, an analytical expression for γ is found that is valid for 0 < k < 3. γ is also determined by using the variational method developed by Bettinson and Rowlands. The two results for γ are compared with a numerical determination.