Screw fixation for supracondylar humerus fractures in children: a report of seventeen cases.

PURPOSE: Supracondylar fractures in the pediatric population are common. For years, K-wires have been the preferred method of surgical fixation. However, fixation with K-wires alone may lead to multiple complications. This study reports the results of surgical care of supracondylar humerus fractures using screw fixation with K-wires or screw fixation alone. METHODS: This study retrospectively reviewed all patients with supracondylar humerus fractures treated with screw fixation between 2007 and 2013. Patients treated only with smooth wires, or having a displaced medial epicondyle, or presenting with lateral condyle fractures were excluded from the study. Flynn's criteria were used to determine the outcome. RESULTS: Seventeen patients who met inclusion criteria formed the study group. All patients were followed until union, resolution of complications, and return to preinjury activity level. Satisfactory outcome was reported in 70.6% of patients with less than 15° loss of either flexion or extension. Mean time to union was 6.5 weeks (range 3.3-12.1 weeks). Screw fixation alone had a shorter mean time to union (5.5 weeks) than compared screw fixation with K-wires group (6.9 weeks). Full range of motion following surgical invention was associated with Flynn's criteria (p value = 0.044). CONCLUSION: Screw fixation for pediatric supracondylar fractures is a viable option to achieve healing and early motion in highly unstable fractures as well as fractures which require (1) increased stability, (2) maintenance of stability during wound checks in the immediate postoperative period and after discontinuation of the cast, or (3) if further exploration like associated vascular injury is warranted.

Pediatric Chondromyxoid Fibroma-Like Osteosarcoma.

Chondromyxoid fibroma-like osteosarcoma (CMF-OS) is a low-grade osteosarcoma, often misdiagnosed on initial biopsy as a benign lesion, with five cases previously described. We report a 13-year-old male with an intramedullary lytic CMF-OS of the right tibial proximal metaphysis with cortical destruction and soft tissue extension. Diagnosis was based on malignant new bone formation, increased mitotic figures, lamellar bone permeation with bony destruction, and correlation with imaging studies. There were no metastasis at presentation and the tumor showed good response to standard chemotherapy with >95% necrosis.

Toward Higher-Order Mass Detection: Influence of an Adsorbate's Rotational Inertia and Eccentricity on the Resonant Response of a Bernoulli-Euler Cantilever Beam.

In this paper a new theoretical model is derived, the results of which permit a detailed examination of how the resonant characteristics of a cantilever are influenced by a particle (adsorbate) attached at an arbitrary position along the beam's length. Unlike most previous work, the particle need not be small in mass or dimension relative to the beam, and the adsorbate's geometric characteristics are incorporated into the model via its rotational inertia and eccentricity relative to the beam axis. For the special case in which the adsorbate's (translational) mass is indeed small, an analytical solution is obtained for the particle-induced resonant frequency shift of an arbitrary flexural mode, including the effects of rotational inertia and eccentricity. This solution is shown to possess the exact first-order behavior in the normalized particle mass and represents a generalization of analytical solutions derived by others in earlier studies. The results suggest the potential for "higher-order" nanobeam-based mass detection methods by which the multi-mode frequency response reflects not only the adsorbate's mass but also important geometric data related to its size, shape, or orientation (i.e., the mass distribution), thus resulting in more highly discriminatory techniques for discrete-mass sensing.

Eosinophilic/T-cell Chorionic Vasculitis: Histological and Clinical Correlations.

Eosinophilic T-cell chorionic vasculitis (E/TCV) is composed of eosinophils and T-lymphocytes originating within chorionic vessels, radiating toward the intervillous space and away from the amnion in a fashion different from the fetal vascular response seen in amnionitis. Clinical significance and risk factors are not well established. We report four pregnancies (five infants, one triplet was spared) with E/TCV, gestational ranging from 23 weeks to term. All had concurrent acute chorioamnionitis, three had the typical acute fetal inflammatory response. One had placental fetal obstructive vasculopathy and an upper extremity reduction defect (radio-ulnar synostosis), the mother had pre-eclampsia. A second case involved 2 of 3 23 week previable triplets. Our third case had a metatarsus varus resistant to casting, the mother had gestational diabetes. The last case was a normal infant. We review the literature, discuss the clinical findings and present the histologic characteristics of this infrequently recognized lesion.

In-Plane Vibration of Hammerhead Resonators for Chemical Sensing Applications.

Thermally excited and piezoresistively detected in-plane cantilever resonators have been previously demonstrated for gas- and liquid-phase chemical and biosensing applications. In this work, the hammerhead resonator geometry, consisting of a cantilever beam supporting a wider semicircular "head", vibrating in an in-plane vibration mode, is shown to be particularly effective for gas-phase sensing with estimated limits of detection in the sub-ppm range for volatile organic compounds. This paper discusses the hammerhead resonator design and the particular advantages of the hammerhead geometry, while also presenting mechanical characterization, optical characterization, and chemical sensing results. These data highlight the distinct advantages of the hammerhead geometry over other cantilever designs.

Infantile fibrosarcoma successfully treated with chemotherapy, with occurrence of calcifying aponeurotic fibroma and pleomorphic/spindled celled lipoma at the site 12 years later.

The treatment of infantile fibrosarcoma has traditionally been wide resection. Chemotherapy has been investigated as an adjuvant and primary treatment in cases in which surgery would cause unacceptable morbidity. Recurrences normally occur within a year of completion of the chemotherapy and display the same histology. We present a child with an infantile fibrosarcoma of the elbow, successfully treated with chemotherapy alone, who developed a calcifying aponeurotic fibroma and a spindle cell/pleomorphic lipoma at the tumor site 12 years later.

Comparative severity of pediatric osteomyelitis attributable to methicillin-resistant versus methicillin-sensitive Staphylococcus aureus.

BACKGROUND: Staphylococcus aureus remains the most common etiology of hematogenous osteomyelitis in children. Recently emerged virulent strains of methicillin-resistant S. aureus (MRSA) strains now predominate. It remains uncertain whether these pathogens cause a measurably more severe illness than methicillin-sensitive strains. METHODS: We reviewed records of 97 pediatric patients with hematogenous osteomyelitis of varying etiologies to determine whether there were significant differences among the groups in terms of predetermined measures of disease severity. These measures included degree and duration of elevated temperature, acute-phase reactants, length of hospitalization, the number of surgical procedures required, and long-term sequelae. RESULTS: Differences in the clinical course of illness were observed. Patients with MRSA had a significant increase in degree and duration of elevated temperature (P = 0.0001 for both), acute-phase reactant measures (white blood cell count, P = 0.0001; C-reactive protein, P = 0.0058; erythrocyte sedimentation rate, P = 0.0046), initial length of hospital stay (P = 0.0001), and surgical interventions (all procedures, P = 0.0001; therapeutic procedures, only P = 0.0002) as compared with patients with osteomyelitis caused by other bacterial pathogens and culture-negative osteomyelitis. A similar general pattern was observed when the analysis was restricted to culture-positive staphylococcal cases only. CONCLUSIONS: Our results support the hypothesis that MRSA produces more severe bone infection and is likely to require more aggressive surgical and medical management.

Generalized model of resonant polymer-coated microcantilevers in viscous liquid media.

Expressions describing the resonant frequency and quality factor of a dynamically driven, polymer-coated microcantilever in a viscous liquid medium have been obtained. These generalized formulas are used to describe the effects the operational medium and the viscoelastic coating have on the device sensitivity when used in liquid-phase chemical sensing applications. Shifts in the resonant frequency are normally assumed proportional to the mass of sorbed analyte in the sensing layer. However, the expression for the frequency shift derived in this work indicates that the frequency shift is also dependent on changes in the sensing layer's loss and storage moduli, changes in the moment of inertia, and changes in the medium of operation's viscosity and density. Not accounting for these factors will lead to incorrect analyte concentration predictions. The derived expressions are shown to reduce to well-known formulas found in the literature for the case of an uncoated cantilever in a viscous liquid medium and the case of a coated cantilever in air or in a vacuum. The theoretical results presented are then compared to available chemical sensor data in aqueous and viscous solutions.

Management of growth arrest: Current practice and future directions.

INTRODUCTION: Premature growth arrest can pose a challenge to the orthopedic surgeon. Various options for treating physeal arrest exist. METHODS: Systematic searches were conducted on PubMed/Medline, ScienceDirect, OVID, and Cochrane Library. Secondary searching was performed, where certain articles from reference lists of the selected studies were reviewed that were not found in the primary search. RESULTS: This review article discusses the different methods of management for premature growth arrest. CONCLUSIONS: The use of mesenchymal stem cells provides a promising alternative treatment modality.

Study of viscoelastic effect on the frequency shift of microcantilever chemical sensors.

Microcantilevers coated with a chemically sensitive layer are increasingly being used in chemical detection systems. The sensitive coating, often a polymer, absorbs specific molecules, which can be detected by monitoring the shift in the mechanical resonant frequency. Usually, the frequency shift resulting from molecular absorption is interpreted as a mass loading effect. However, mass loading is not the only effect that has an impact on the frequency shift; the viscoelastic properties of the sensitive coating also are affected by the sorption process. Sorption-induced modulus changes are typically difficult to characterize. However, it is known that the sorption of analyte molecules in a polymer coating results in the plasticization of the coating. In most cases, the polymer becomes more rubbery with increasing concentration of analyte molecules, i.e., the coating becomes softer with increasing loss modulus, and the storage modulus decreases. Using a new analytical model developed for the resonant frequency expression of a hybrid microcantilever (elastic base and viscoelastic layer), the effects of the modification of the storage and loss moduli of the sensitive layer on the resonant frequency are examined. The main conclusion of this analytical study is that, even if the sensitive coating moduli are small compared to the base cantilever's Young's modulus, the effect of the change in the viscoelastic coating properties could contribute significantly to the overall frequency shift (8-23% in the simulations depending on the coating thickness, with even higher contributions for other sets of problem parameters).

Late radial head dislocation with radial head fracture and ulnar plastic deformation.

Type II Monteggia lesion equivalents produced by plastic deformation of the ulna are rare. Radial head fractures in skeletally immature patients are also uncommon. We report a late presentation of a Type II Monteggia equivalent injury with a fracture of the radial head and neck and plastic deformation of the ulna in an 11-year-old boy. The radial head was located on the initial injury radiographs and subsequently dislocated in a posterior direction. The radial head fracture was misdiagnosed as a coronoid fracture at presentation. The plastic deformation of the ulna was diagnosed several weeks after the injury when the dislocation was first noted. Magnetic resonance imaging was used to establish the diagnosis of a radial head fracture at the same time. The patient was treated successfully with an open reduction and internal fixation of the radial head combined with a dorsal closing-wedge ulnar osteotomy.

Congenital subcutaneous dendritic cell rich lymphoepithelial hamartoma.

We present the clinical, radiologic, histologic, immunohistochemical, and ultrastructural characteristics of a congenital pretibial subcutaneous lesion composed of a mixture of T and B cells, epithelial cells, and dendritic cells, probably representing a hamartoma. After total removal, there has been no recurrence. The prominent dendritic component of this lesion, demonstrated immunohistochemically and ultrastructurally, separates the lesion from cutaneous lymphadenoma and other adnexal tumors.

Giant cell tumor of tendon sheath arising in the toe.

Giant cell tumor of the tendon sheath (nodular synovitis) is a benign soft tissue tumor, usually affecting older women, that most often occurs in the interphalangeal joints of the fingers. Occurrence is rare in children. We present a 12-year-old boy and a 6-year-old girl with giant cell tumors of tendon sheaths occurring in the toes. The tumor from the 12-year-old demonstrated the cytogenetic finding of t(1;2)(p13;q37), which previously has been associated with giant cell tumor of tendon sheath in adults. Giant cell tumors of the tendon sheath occurring in children have similar histological and cytogenetic features as adults, however, there may be a predilection for lower extremity involvement.