Factors affecting bone mineral mass loss after lower-limb fractures in a pediatric population.

BACKGROUND: The purpose of this study was to assess the effects of the durations of cast immobilization and non-weight-bearing periods, and decreases in vigorous physical activity (VPA) on bone mineral parameters in a pediatric population treated for a lower-limb fracture. METHODS: Fifty children and teenagers who had undergone a cast-mediated immobilization for a leg or ankle fracture were prospectively recruited. The durations of cast immobilization and non-weight-bearing periods were recorded for each participant. Dual-energy x-ray absorptiometry scans were performed at the time of fracture treatment (baseline) and at cast removal. Physical activity during cast immobilization was assessed using accelerometers. RESULTS: A strong negative correlation was found between the total duration of cast immobilization and decreases in both calcaneal bone mineral density (BMD) (r=-0.497) and total lower-limb bone mineral content (BMC) (r=-0.405). A strong negative correlation was also noted between the durations of the non-weight-bearing periods and alterations in calcaneal BMD (r=-0.420). No apparent correlations were found between lower BMD and BMC and decreased VPA. CONCLUSIONS: Bone mineral loss was correlated to the total duration of cast immobilization for all measurement sites on the affected leg, whereas it was only correlated to the durations of non-weight-bearing periods for calcaneal BMD and total lower-limb BMC. However, no correlations were noted between bone mineral loss and decreased VPA.

Nanoneedles of Mixed Transition Metal Phosphides as Bifunctional Catalysts for Electrocatalytic Water Splitting in Alkaline Media.

In this work, mixed Ni/Co and Ni/Fe metal phosphides with different metal ratios were synthesized through the phosphidization of high-surface-area hydroxides grown hydrothermally on carbon cloth. The materials were characterized by means of X-ray photoemission spectroscopy, X-ray diffraction, energy dispersive X-ray analysis, and electron microscopies. The electrocatalytic performance in the electrochemical water splitting was tested in alkaline media. With the aim of determining the chemical stability of the mixed phosphides and the possible changes undergone under catalytic conditions, the materials were characterized before and after the electrochemical tests. The best performances in the hydrogen evolution reaction were achieved when synergic interactions are established among the metal centers, as suggested by the outstanding performances (50 mV to achieve 10 mA/cm2) of materials containing the highest amount of ternary compounds, i.e., NiCoP and NiFeP. The best performances in the oxygen evolution reaction were reached by the Ni-Fe materials. Under these conditions, it was demonstrated that a strong oxidation of the surface and the dissolution of the phosphide/phosphate component takes place, with the consequent formation of the corresponding metal oxides and hydroxides.

Risk factors for post-traumatic osteoarthritis of the ankle: an eighteen year follow-up study.

PURPOSE: Long-term studies evaluating risk factors for development of ankle osteoarthritis (OA) following malleolar fractures are sparse. METHODS: We conducted a retrospective cohort study including consecutive patients treated by open reduction and internal fixation for malleolar fracture between January 1988 and December 1997. Perioperative information was obtained retrospectively. Patients were evaluated clinically and radiographically 12-22 years postoperatively. Radiographic ankle OA was determined on standardised radiographs using the Kellgren and Lawrence scale (grade 3-4=advanced OA). Uni- and multivariate regression analyses were performed to determine risk factors for OA. RESULTS: During the inclusion period, 373 fractures (372 patients; 9% Weber A, 58% Weber B, 33% Weber C) were operated upon. The mean age at operation was 42.9 years. There were 102 patients seen at follow-up (mean follow-up 17.9 years). Those not available did not differ in demographics and fracture type from those seen. Advanced radiographic OA was present in 37 patients (36.3%). Significant risk factors were: Weber C fracture, associated medial malleolar fracture, fracture-dislocation, increasing body mass index, age 30 years or more and length of time since surgery. CONCLUSIONS: Advanced radiographic OA was common 12-22 years after malleolar fracture. The probability of developing post-traumatic OA among patients having three or more risk factors was 60-70%.

Patient positioning on the operative table for more accurate reduction during elastic stable intramedullary nailing of the femur: a technical note.

Elastic stable intramedullary nailing is currently considered a clinical practice standard for the treatment of femoral fractures in children in the age-appropriate group. Malreduction, particularly in rotation, due to the closed reduction technique has been reported. We describe a new technique of positioning on a standard operating table that permits better control of rotational alignment during femoral elastic stable intramedullary nailing.

Osteoarticular infections in young children: what has changed over the last years?

Osteoarticular infections remain a significant cause of morbidity worldwide in young children. They can have a devastating impact with a high rate of serious and long-lasting sequelae, especially on remaining growth. Depending on the localisation of infection, they manifest as osteomyelitis, septic arthritis, a combination of both (i.e., osteomyelitis with adjacent septic arthritis) or spondylodiscitis. Osteoarticular infections can be divided into three types according to the source of infection: haematogenous; secondary to contiguous infection; or secondary to direct inoculation. During the last few years, many principles regarding diagnostic assays and the microbiological causes of these infections have evolved in a significant manner. In the present current-opinion review, we discuss recent concepts regarding epidemiology, physiopathology, and the microbiology of bone and joint infections in young children, as well as clinical presentations, diagnosis, and treatment of these infections. Clinicians caring for children need to be especially well versed in these newer concepts as they can be used to guide evaluation and treatment.