Surgical technique: Tscherne-Johnson extensile approach for tibial plateau fractures.

BackgroundThe standard approach to lateral tibial plateau fractures involves elevation of the iliotibial band (IT) and anterior tibialis origin in continuity from Gerdy's tubercle and metaphyseal flare. We describe an alternative approach to increase lateral plateau joint exposure and maintain iliotibial band insertion to Gerdy's tubercle.Description of techniqueThe approach entails a partial tenotomy of the anterior half of the IT band leaving the posterior IT band insertion attached to Gerdy's tubercle. Fracture lines around Gerdy's tubercle are completed or the tubercle was osteotomized and externally rotated and the joint overdistracted, allowing direct visualization of the joint depression. Joint elevation, grafting, and internal fixation are performed through this window.MethodsWe retrospectively reviewed 76 patients (two groups), Schatzker Types I to II and IV to VI fractures (66 patients), between 1989 and 2005, and 10 patients, with 10 bicondylar posterior plateau fractures, from 2002 to 2010. All patients were followed a minimum of 12 months (average, 3.9 years; range, 12 months to 10 years). Ten patients, with posterior plateau fractures, received anterolateral plateau intraarticular osteotomy for exposure of centroposterior and posterolateral articular depression.ResultsAverage knee ROM was 2° of flexion (range, -3° to 5°) to greater than 120° of flexion (range, 100°-145°). In 66 patients, average articular depression improved from 7.4 mm to 1 mm (range, 0-5 mm) and, in 10 posterior fractures, from 18 mm to 1 mm (range, 0-4.5 mm). Infection occurred in one of the 76 patients; acute débridement and intravenous antibiotics resulted in control of the infection.ConclusionsThis approach reliably increases direct visualization of the lateral plateau articular fractures and maintains IT band insertion. Articular osteotomy of the anterolateral plateau provides access to extensive posterior plateau fractures

Direct Anterior versus Lateral Approach for Femoral Neck Fracture: Role in COVID-19 Disease

Background: During the COVID-19 emergency, the incidence of fragility fractures in elderly patients remained unchanged. The management of these patients requires a multidisciplinary approach. The study aimed to assess the best surgical approach to treat COVID-19 patients with femoral neck fracture undergoing hemiarthroplasty (HA), comparing direct lateral (DL) versus direct anterior approach (DAA). Methods: A single-center, observational retrospective study including 50 patients affected by COVID-19 infection (30 males, 20 females) who underwent HA between April 2020 to April 2021 was performed. The patients were allocated into two groups according to the surgical approach used: lateral approach and anterior approach. For each patient, the data were recorded: age, sex, BMI, comorbidity, oxygen saturation (SpO2), fraction of the inspired oxygen (FiO2), type of ventilation invasive or non-invasive, HHb, P/F ratio (PaO2/FiO2), hemoglobin level the day of surgery and 1 day post operative, surgical time, Nottingham Hip Fractures Score (NHFS) and American Society of Anesthesiologists Score (ASA). The patients were observed from one hour before surgery until 48 h post-surgery of follow-up. The patients were stratified into five groups according to Alhazzani scores. A non-COVID-19 group of patients, as the control, was finally introduced. Results: A lateral position led to a better level of oxygenation (p < 0.01), compared to the supine anterior approach. We observed a better post-operative P/F ratio and a reduced need for invasive ventilation in patients lying in the lateral position. A statistically significant reduction in the surgical time emerged in patients treated with DAA (p < 0.01). Patients within the DAA group had a significantly lower blood loss compared to direct lateral approach. Conclusions: DL approach with lateral decubitus seems to preserved respiratory function in HA surgery. Thus, the lateral position may be associated with beneficial effects on gas exchange

The functional outcome of direct lateral approach for fixation of proximal humeral fractures: A case series from a tertiary care hospital

Displaced proximal humeral fractures warrant surgical fixation for early rehabilitation and better functional outcome. These fractures are traditionally fixed by delto pectoral surgical approach. Direct lateral approach has recently gained interest as it involves less soft tissue dissection and is particularly helpful in certain fracture patterns. However, there have been concerns of axillary nerve damage with this approach. We report a case series of proximal humerus fractures fixed by direct lateral approach from our institution. All displaced Type 2 and 3 fractures were included in our study. Pathological and comminuted Type 4 fractures and fractures with ipsilateral clavicle or elbow fractures were excluded. Oxford Shoulder Score was done at regular intervals for assessment of functional outcome. We did not observe any axillary nerve damage in our case series and the outcomes of 70.5% of our patients were excellent while in 29.5% it was good. We recommend direct lateral approach for specific pattern of proximal humerus fractures

Surgical approach in primary total hip arthroplasty: Anatomy, technique and clinical outcomes

©2015 8872147 Canada Inc. Total hip arthroplasty (THA) has revolutionized the treatment of hip arthritis. A number of surgical approaches to the hip joint exist, each with unique advantages and disadvantages. The most commonly used approaches include the direct anterior, direct lateral and posterior approaches. A number of technical intricacies allow safe and efficient femoral and acetabular reconstruction when using each approach. Hip dislocation, abductor insufficiency, fracture and nerve injury are complications of THA, although their relative risk varies by approach. Numerous clinical trials have sought to elicit differences in patient-reported outcomes, complication rates and return to function among the surgical approaches. This review outlines some of the technical pearls of performing a THA through either a direct anterior, direct lateral or posterior approach. A literature review outlines the impact of surgical approach on clinical outcomes and clinically relevant complication rates

When atomic-scale resolution is not enough: Spatial effects in in situ model catalyst studies

We investigate transport effects in in situ studies of defined model catalysts using a multi-scale modeling approach integrating first-principles kinetic Monte Carlo simulations into a fluid dynamical treatment. We specifically address two isothermal flow setups: i) a channel flow with the gas-stream approaching the single crystal from the side, as is representative for reactor scanning tunneling microscopy experiments; and ii) a stagnation flow with perpendicular impingement. Using the CO oxidation at RuO2 (110) as showcase we obtain substantial variations in the gas-phase pressures between the inlet and the catalyst surface. In the channel geometry the mass transfer limitations lead furthermore to pronounced lateral changes in surface composition across the catalyst surface. This prevents the aspired direct relation between activity and catalyst structure. For the stagnation flow the lateral variations are restricted to the edges of the catalyst. This allows to access the desired structure-activity relation using a simple model.Comment: 22 pages, 7 figure

Intermolecular Effect in Molecular Electronics

We investigate the effects of lateral interactions on the conductance of two molecules connected in parallel to semi-infinite leads. The method we use combines a Green function approach to quantum transport with density functional theory for the electronic properties. The system, modeled after a self-assembled monolayer, consists of benzylmercaptane molecules sandwiched between gold electrodes. We find that the conductance increases when intermolecular interaction comes into play. The source of this increase is the indirect interaction through the gold substrate rather than direct molecule-molecule interaction. A striking resonance is produced only 0.3 eV above the Fermi energy.Comment: 4 pages, 5 figure

Soft tissue damage after minimally invasive THA: A comparison of 5 approaches

Methods 5 surgeons each performed a total hip arthroplasty on 5 fresh frozen cadaver hips, using either a MIS anterior, MIS anterolateral, MIS 2-incision, MIS posterior, or lateral transgluteal approach. Postoperatively, the hips were dissected and muscle damage color-stained. We measured proportional muscle damage relative to the midsubstance cross-sectional surface area (MCSA) using computerized color detection. The integrity of external rotator muscles, nerves, and ligaments was assessed by direct observation. Results None of the other MIS approaches resulted in less gluteus medius muscle damage than the lateral transgluteal approach. However, the MIS anterior approach completely preserved the gluteus medius muscle in 4 cases while partial damage occurred in 1 case. Furthermore, the superior gluteal nerve was transected in 4 cases after a MIS anterolateral approach and in 1 after the lateral transgluteal approach. The lateral femoral cutaneous nerve was transected once after both the MIS anterior approach and the MIS 2-incision approach. Interpretation The MIS anterior approach may preserve the gluteus medius muscle during total hip arthroplasty, but with a risk of damaging the lateral femoral cutaneous nerv

A Model for Isotropic Crystal Growth from Vapor on a Patterned Substrate

We developed a consistent mathematical model for isotropic crystal growth on a substrate covered by the mask material with a periodic series of parallel long trenches where the substrate is exposed to the vapor phase. Surface diffusion and the flux of particles from vapor are assumed to be the main mechanisms of growth. A geometrical approach to the motion of crystal surface in two dimensions is adopted and nonlinear evolution equations are solved by a finite-difference method. The model allows the direct computation of the crystal surface shape, as well as the study of the effects due to mask regions of effectively nonzero thickness. As in experiments, lateral overgrowth of crystal onto the mask and enhanced growth in the region near the contact of the crystal and the mask is found, as well as the comparable crystal shapes. The growth rates in vertical and lateral directions are investigated.Comment: 21 pages; submitted to the Journal of Crystal Growt