Ileofemoral flaps--a clinical study (author's transl)]

The authors reveiw the anatomy, circulation, planning and techniques of preparing ileofemoral flaps. The possibilities of application of these flaps, advantages and disadvantages of the procedure are discussed. The authors use ileofemoral flaps as a new effective procedure for covering sores of the trochante area.     

Revisiting the concept of talar shift in ankle fractures

BACKGROUND: In 1976, Ramsey and Hamilton published a classic experiment investigating the biomechanical effects of talar shift in a simple ankle fracture model. Their finding was that 1 mm of talar shift resulted in a 42% decrease in tibiotalar contact surface area. Based on this conclusion, 1 mm of talar shift became the recognized indication for operative fixation. METHODS: Twelve cadaver ankles were dissected and the distal tibia coated with carbon powder. A 70-kg load was applied to the distal tibia that resulted in transference of the carbon onto the talus. The contact surface area was determined at 0, 1, 2, 4 and 6 mm of talar shift using spacers fixed in the medial gutter. Tracing paper was used to mark the outline of the contact area and measured using graph paper. RESULTS: Our results were similar to Ramsey and Hamilton's original experiment. One millimeter of lateral talar shift resulted in 40% loss of contact surface area compared with 42% in the original experiment. A large variance was seen in talar contact surface area depending on the morphology of the ankle joint. CONCLUSION: Ramsey and Hamilton's original experiment was valid.     

The molecular biology of pulmonary metastasis

Curing cancer requires the treatment of metastatic disease. Whether this is a patient with advanced disease and clinically apparent metastases, or if the patient with localized disease is at risk for development of dissemination, failure to control metastasis will result in a poor outcome. Here, we have presented a molecular guide to our current understanding of the processes underlying metastasis. Experimental clinical trials designed to further the understanding of metastasis are often limited by selection of patients with advanced disease. Therefore, our understanding of the processes involved in the metastatic cascade is limited by the availability of comprehensive experimental model systems. The study of metastasis relies most heavily on xenografts, tumors using human cell lines, or tumor tissue that can grow in mice. These models present a limited recapitulation of the patients. Xenograft models require some degree of immunosuppression on the part of the host, because mice with native immune systems will reject transplanted human tumors, preventing their growth. As a result, mice with immune defects ranging from depleted T cells (nude mice) to absent T, B, and NK cells (SCID-Beige) are used as hosts. As the evasion of the immune system is a key function demonstrated by the metastatic cancer cell, xenograft models, by necessity, subvert this step. Furthermore, recent studies have established that angiogenesis in transplanted tumors is different than in native tumors, further highlighting the limitations of these models. With these limitations, studies of metastasis may require development of models of autochthonous tumors, that is, tumors originating in the study animals. A number of cell lines of autochthonous murine tumors have been established that generate metastatic disease after implantation into mice. Moreover, some transgenic animals spontaneously develop metastatic tumors that, although occurring in genetically engineered animals, may represent the most complete model from early development to late effects. Finally, a very promising field of autochthonous tumor studies lies in work with companion animals (pets). Some dogs will have cancer, often with striking similarities to those of their human counterparts. These pets may represent an important study group, because they have autochthonous tumors, occurring spontaneously, in an outbred population. In all of these cases, the tumor, new vasculature, and the immune system are syngeneic with the host. In addition to the advances in model systems, advances in technology will further our understanding and ability to combat metastatic disease. As demonstrated, genomics is proving to be a powerful tool in identifying those at risk for metastasis. From these genetic signatures, molecular targets may be deduced from the genes altered in patients with poor prognoses. Furthermore, other molecular tools such as proteomic analysis may provide further information. Clearly, therefore, a synthesis of different technologies and complimentary information will be required to target metastases and improve the outcome for patients affected by them.     

Regular vs ad-lib albuterol for patients hospitalized with acute asthma

STUDY OBJECTIVES: Inhaled, short-acting beta-agonists and systemic corticosteroids form the mainstay of therapy in acute asthma exacerbation. Asthma, however, is an inflammatory disease of the airways, and its underlying pathology is not impacted by short-acting beta-agonists. While the efficacy of ad-lib beta-agonist administration in outpatient management of asthma symptoms is well established, little data exist to support this strategy in patients with acute, severe asthma. We postulate that as long as patients hospitalized with severe asthma exacerbation receive systemic corticosteroids, regular, scheduled administration of short-acting beta-agonists is unnecessary. Similar therapeutic outcomes can be achieved with the ad-lib administration of the short-acting beta-agonists. DESIGN: Prospective, randomized, double-blind, placebo-controlled trial. SETTING: Pulmonary floor of a 600-bed municipal hospital.Patients or participants: Sixty-two patients hospitalized for acute asthma. INTERVENTIONS: Patients were randomized to receive either albuterol nebulizations (regular albuterol group) or saline solution nebulizations (ad-lib group) every 4 h with management of breakthrough symptoms with albuterol metered-dose inhaler or nebulizations for both groups. All patients received systemic corticosteroids. Peak expiratory flows, asthma symptoms, and need for rescue bronchodilator were followed up on each patient until discharge. RESULTS: There was no significant difference in the length of hospitalization (median length, 48 h for ad-lib group vs 57.5 h for regular albuterol group, p = 0.82), rate of improvement in peak flow, or symptoms between the two groups. Ad-lib beta-agonist use compared to regular albuterol scheduled use resulted in a significant reduction in the total number of albuterol treatments administered (median, 7 treatments vs 19 treatments, p = 0.001) during hospitalization. CONCLUSIONS: In the management of asthma exacerbation, ad-lib administration of albuterol is therapeutically as effective as regular, scheduled administration. This method of drug administration also reduces the total dose of beta-agonists received by the hospitalized patient.     

Porous polysulfone coatings for enhanced drug delivery

The synthesis of a porous polysulfone (PSU) coating for use in drug delivery applications is presented. PSU can serve as a functional surface coating for drug delivery vehicles, such as intraocular biomicrorobots. The coatings can be applied using spin coating or dip coating. The porosity is introduced by selectively dissolving calcium carbonate nanoparticles embedded in the bulk polymer. The network of pores thus formed increases by a factor of thirty the amount of Rhodamine B (model drug) that can be loaded and by a factor of fifteen the amount that can be released. The films do not affect cell viability and exhibit poor cell adhesion. The straightforward synthesis and predictability of porosity enables the tuning of the amount of drug that can be loaded.     

Kinematics of medial osteoarthritic knees before and after posterior cruciate ligament retaining total knee arthroplasty

Total knee arthroplasty (TKA) is a widely accepted surgical procedure for the treatment of patients with end‐stage osteoarthritis (OA). However, the function of the knee is not always fully recovered after TKA. We used a dual fluoroscopic imaging system to evaluate the in vivo kinematics of the knee with medial compartment OA before and after a posterior cruciate ligament‐retaining TKA (PCR‐TKA) during weight‐bearing knee flexion, and compared the results to those of normal knees. The OA knees displayed similar internal/external tibial rotation to normal knees. However, the OA knees had less overall posterior femoral translation relative to the tibia between 0° and 105° flexion and more varus knee rotation between 0° and 45° flexion, than in the normal knees. Additionally, in the OA knees the femur was located more medially than in the normal knees, particularly between 30° and 60° flexion. After PCR‐TKA, the knee kinematics were not restored to normal. The overall internal tibial rotation and posterior femoral translation between 0° and 105° knee flexion were dramatically reduced. Additionally, PCR‐TKA introduced an abnormal anterior femoral translation during early knee flexion, and the femur was located lateral to the tibia throughout weight‐bearing flexion. The data help understand the biomechanical functions of the knee with medial compartment OA before and after contemporary PCR‐TKA. They may also be useful for improvement of future prostheses designs and surgical techniques in treatment of knees with end‐stage OA. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:40–46, 2011     

Gender differences in the knees of Chinese population

The goal of this study was to characterize the geometry of the distal femur and proximal tibia in the Chinese population. Three-dimensional models of twenty female and twenty male knees were constructed using CT images. The morphologic measurements of the distal femur included mediolateral (ML) and anteroposterior dimension of medial and lateral condyles (MAP, LAP), femoral aspect ratio (ML/LAP), medial and lateral condylar width, intercondylar notch width, notch width index (NWI), and trochlear groove orientation. The sagittal profiles of the medial and lateral femoral condyles and tibial plateaus were also characterized. The results showed that the size of the distal femur of the females was significantly smaller than that of the males. Furthermore, when normalized by LAP, the females had a significantly narrower distal femur (ML), and a shorter MAP compared to the males. In the sagittal plane, the radius of the lateral distal circle of the femur was significantly smaller than that of the medial condyle in both genders. There were no significant gender differences in the proximal tibial geometry. The data of the present study may enable suitable modification of total knee prosthesis sizing/geometry for Asia-Pacific patients.