Chapter 19. Injuries of the musculoskeletal system in children

The provision of trauma care to children has a number of significant differences that distinguish pediatric traumatology in a separate specialty that requires special training of medical personnel. These differences relate to the anatomical and physio-logical characteristics of the child's body, the mechanism of damage, the collection of complaints and anamnesis, the principles of diagnosis and treatment, rehabilitation measures.

Anatomical and physiological features

As a result of the lower mineral content, the bones of the child are more flexible and elastic than in an adult, but thinner and less durable. Bone durability and elasticity depend on the ratio of organic (ossein) and mineral parts (1:2). In young children, the content of ossein in the bones is relatively higher - up to 50%.

Periosteum in children is much thicker and provides not only additional elasticity and bone protection but also accelerated (2-2.5 times faster than in adults) fusion of the fracture due to the rich blood supply. Even with a significant displacement of bone fragments, with their minimal mutual contact, as a rule, consolidation occurs. False joints in children are exceptionally rare. The absence of osteoporosis in a healthy child practically excludes such injuries typical for the elderly and senile age, as fractures of the femoral neck, shoulder neck, distal metaepiphysis of the forearm bones. These fractures in children can occur only as a result of a strong direct blow.

The junction of the metaphyseal zone of tubular bones with the epiphysis by elastic cartilage tissue gives the bone additional flexible properties, but it is also a zone of reduced strength, which can be damaged in trauma. Such injuries - epiphysiolyses-constitute a significant danger for further development of the child's skeleton, since this is where the bone growth zone is located (Table 19.1). Violation of these zones (both in case of trauma or surgical interventions) leads to a slowdown or complete cessation of bone growth and development with the formation of skeletal deformities.

Ossification ("closure") of growth plates occurs at different times depending on the localization and is mainly completed by 15-17 years of age. With preserved growth plates, as a result of high plasticity of bone and connective tissue in children, angular post-traumatic deformities of diaphyses up to 10-20°, displacements in width almost to the diameter of the bone and shortening along the length to 2 cm can be completely leveled. Such spontaneous correction is the more pronounced the younger the child.

Table 19.1. The importance of epiphyseal zones for bone growth in length (Digby diagram)

Due to increased hydrophilicity of tissues, children are characterized by a rapid (within 1-3 hours) development of post-traumatic edema of soft tissues, which complicates reposition, can lead in a short time to the development of limb ischemia, and after the edema subsides - to a secondary displacement of bone fragments in a plaster cast. In addition, in the first days after the injury, the child is characterized by general hyperthermia up to 38 °С.

Types of bone damage in children

In addition to the variants of fractures, characteristic of adults, the following injuries are typical for children:

• greenstick fractures - are characteristic of damage to the diaphyseal part of the bone (more often the forearm). The bone is bent; on its convex side, there is a fracture of the outer layers; on its concave side, the bone is not damaged due to elasticity;
• subperiosteal fractures - are also characteristic of the diaphyseal part of the tubular bones (more often the forearm and lower leg) when forces are exerted along the longitudinal axis. The bone is damaged, but the periosteum remains intact, holding fragments, the displacement of which is either completely absent or insignificant;
• epiphysiolysis and osteoepiphysiolysis - occur only in children and adolescents until the end of the ossification process, as they are damage to the cartilage tissue in the connection of the tubular bone metaphysis with the epiphysis. According to the mechanism of injury, epiphysiolysis is similar to dislocation in adults and occurs where the joint capsule attaches to the epiphyseal plate: the growth epiphyseal plate is destroyed with the separation and displacement of the epiphysis relative to the metaphysis (Fig. 19.1, a). In osteoepiphysiolysis, a part of the metaphysis is also damaged (Fig. 19.1, b).
• apophysiolysis (detachments of apophysis along the line of the germ cartilage) - extra-articular injuries are akin to detachable fractures of similar localization in adults (Fig. 19,1, b).

Fig. 19.1. Damage to the cartilage in the germ zone of the bone in children: a) epiphysiolysis; b) osteoepiphysiolysis; c) apophysiolysis

Mechanisms of injury

Each age period has its most typical situations, fraught with injuries. We can distinguish birth injuries, as well as injuries in children under the age of one year (until the child began to walk), from one year to 6-7 years (preschool period), over 7 years (school period). A body weight less than in adults and a more pronounced array of soft tissues in combination with a small growth, lead to the fact that fractures and dislocations in children in case of fall (and children fall, especially in the first years of life, very often) are relatively rare. At the same time, a small muscle mass, relative weakness of the capsular-ligamentous apparatus of the joints cause a number of typical injuries for each age period that are not characteristic of adults. These injuries are discussed in the following sections.