FRACTURE OF THE HUMERUS IN CHILDREN ­ CAUSES AND MECHANISMS OF INJURY. / PRIJELOMI NADLAKTICNE KOSTI U DJECE ­ OKOLNOSTI I UZROCI NASTANKA.

Due to hyperactivity, children are often exposed to injuries of the upper arm and fractures of the humerus can leave permanent damage even after the surgical treatment. The high incidence of fractures justifi es questioning the possible prevention of this injury. Preventive actions are possible only with the knowledge of the causes and circumstances of the fracture. Aim is to analyze the circumstances of the injury, critical places and activities engaged in at the time of the humeral fracture by age groups. The paper analyzed 102 children that were treated at the University Hospital Centre in Zagreb due to fractures of the humerus in the period from 2010 to 2014. In this study, we analyzed 45 girls (44%) and 57 boys (56%). The average age of children was 8.3 years. Fractures of the distal third of the humerus accounted for 4/5 of all analyzed fractures. The right hand was affected more frequently. Nearly 80% of fractures were unstable, which generally require surgical treatment. The injury occurred most often among the 5-9 year-olds. Most injuries took place at the recreational facilities (47%), followed by injuries at home (31%), on streets or roads (15%) and at school or kindergarten (7%). Mechanism of the injury was mainly a fall onto the arm (94%) and the rest of the injuries were due to a direct blow. Almost half of the children got injured in sports or recreational activities. Due to close physical contact and engagement in games, children in preschool and early school age are by far the most susceptible to injuries. To reduce the incidence of such injuries, preventive actions should be taken during daily activities under the supervision of parents towards the most vulnerable age group (5-9 years), along with increasing the supervision in preschools and schools. Of all the activities, the most dangerous to cause fractures of the humerus occur in sports grounds and recreational facilities of preschool children and children in the lower grades of elementary school.

[EXOTHERMIC REACTIONS OF PLASTER IMMOBILIZATION ­ ANALYSIS OF THREE KINDS OF PLASTER BANDAGES].

Exothermic reaction of plaster is a very important characteristic to understand, especially when it comes to complications which can occur during local temperature change during molding plaster of Paris. And these complications directly influence the speed and quality of treatment. In this paper we measured temperatures of plaster bandage tiles 10×10 cm, from three different manufacturers in Croatian hospitals: Safix plus (Hartmann, Germany), Cellona (Lohmann &Rauscher, Austria) and Gipsan ( Ivo Lola Ribar, Croatia). We made three different plaster tiles 10×10 cm, from 10, 15 and 30 layers of plaster bandages. We immersed plaster tiles in two different water temperatures, one group in water 22 °C, and another in 34 °C. Although all plaster bandages have similar chemical characteristics, we have measured some differences. All three kinds of plaster bandages used in Croatia have low exothermic reaction when plaster molding is done in standard conditions, average local temperature is low and there is no danger of local burns. We immersed a plaster tile with 15 layers in water on 34° C, and highest average temperature was measured at Gipsan (46.2 °C), then Cellona (41.3 °C) and Safix plus (38.9 °C). On the same water immersion temperature, on plaster tile with 30 layers average temperatures were Gipsan (48.4°C), Cellona (45.4 °C), and lowest in Safix plus (41.3 °C). Plaster tiles form all manufacturers, when used 15-30 layers thick, and water immersion temperature is 34°C, develop average temperature over 40°C, in duration from 8-12 minutes. Between three different plaster bandages analyzed, Gipsan (Ivo Lola Ribar, Croatia) developed highest temperature, and some plaster tiles were measured over 50 °C.

[PHYSICAL PROPERTIES OF PLASTER BANDAGES]. / FIZIKALNA SVOJSTVA SADRENIH ZAVOJA.

The physical properties of plaster bandages are a very important factor in achieving the basic functions of immobilization (maintaining bone fragments in the best possible position), which directly affects the speed and quality of fracture healing. This paper compares the differences between the physical properties of plaster bandages (mass, specific weight, drying rate, elasticity and strength) and records the differences in plaster modeling of fast bonding 10 cm wide plaster bandages, from three different manufacturers: Safix plus (Hartmann, Germany), Cellona (Lohman Rauscher, Austria) and Gipsan (Ivo Lola Ribar ltd., Croatia). Plaster tiles from ten layers of plaster, dimension 10 x 10 cm were made. The total number of tiles from each manufacturer was 48. The water temperature of 22 °C was used for the first 24 tiles and 34 'C was used for the remainder. The average specific weight of the original packaging was: Cellona (0.52 g/cm3), Gipsan (0.50 g/cm3), Safix plus (0.38 g/cm3). Three days after plaster tile modeling an average specific weight of the tiles was: Gipsan (1.15 g/cm3), Safix plus (1.00 g/cm3), Cellona (1.10 g/cm3). The average humidity of 50% for Safix plus and Cellona plaster tiles was recorded 18 hours after modeling, while for the Gipsan plaster tiles, this humidity value was seen after 48 hours. On the third day after plaster modeling the average humidity of the plaster tiles was 30% for Gipsan, 24% for Safix and 16% for Cellona. Cellona plaster tiles made with 34 °C water achieved the highest elasticity (11.75±3.18 MPa), and Gipsan plaster tiles made with 22 °C had the lowest (7.21±0.9 MPa). Cellona plaster tiles made with 34 °C water showed maximum material strength (4390±838 MPa), and Gipsan plaster tiles made with 22 °C water showed the lowest material strength (771±367 MPa). The rigidity and strength of Cellona and Gipsan plaster are higher in tiles made in warmer water, and for Safix plus are higher in tiles made in cooler water. All three types of plaster differentiate in physical properties. The differences in mass and specific weight before and after plaster modeling are minimal. There are greater differences in drying rate, elasticity and strength between the three different plaster materials.

[HAND FRACTURES IN CHILDREN - CAUSES AND MECHANISMS OF INJURY]. / PRIJELOMI KOSTIJU SAKE U DJECE - OKOLNOSTI I UZROCI NASTANKA.

Hand is extremely exposed to various loads and traumas of everyday tasks and activities, resulting in fist fractures being fairly common injuries. The most common mechanism of injury is a direct blow. This retrospective study analyzed the data on 274 children admitted for hand fractures at Clinical Hospital Center Zagreb in the period from 2006 to 2014. The study included 76 girls (28%) and 198 boys (72%). The average patient age was 11.9 years and most were between 10 and 13 years of age. Phalangeal fractures accounted for 80%, metacarpal fractures for 17%, and carpal fractures for 3% of all injuries. Most commonly injuries occurred during recreation (4 1%), at home (37%), at school (18%) and in the street (4%). Direct blow was the major cause of injury (76%), and 24% were caused by fall. Injuries during sport activities are the most common cause of the hand fractures in pediatric population and direct blow is the main mechanism of injury. The peak incidence is at the age of 10-13 years in boys and girls, so prevention should be aimed at this age group. Preventive actions should be focused on injuries that tend to occur in parks, schools and during sport activities.