Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon

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Traumatic injuries

Children and adolescents are injured more often than adults, but their injuries are usually less serious. This may partly be due to the fact that children are physically smaller than adults, so that less force is involved in the injury. Children’s tissues are significantly different from those of adults: their bone structure is more resilient and adaptable, and their muscles, tendons, and ligaments are relatively stronger and more elastic. Unlike the situation in adults, the articular cartilages have some blood supply, enabling injuries in those areas to heal to some extent.
The skeleton is the most vulnerable structure in adolescents. Though the bones are adaptable to various stresses, and in this respect are superior to those of adults, they are not as adaptable as the cardiovascular system and the muscles. In children and adolescents who participate in regular training, the musculature can develop more rapidly than the skeleton, which may be hazardous because of the unusual stress it imposes.Because of the resilience of the tissues, overuse injuries are relatively rare in children and young people, although in recent years their incidence has been increasing noticeable, probably because of more intensive training in younger children.

Injuries to the growth zones
Growth in length of the skeleton takes place in the growth zones or epiphyseal cartilages. In the femur 70% of the growth occurs in the lower epiphysis and 30% in the upper. Corresponding figures for the lower leg are 55% and 45% respectively. The epiphyseal cartilages are weaker than the rest of the skeleton and are susceptible to injury.The age of the skeleton has a role in determining the effect of physical training on the epiphyseal cartilages. Hormone factors are also important. The epiphyseal cartilages are at their weakest during puberty and towards the end of the growth period when they are beginning to lose their elastic properties.

Epiphyseal cartilages are weaker than normal tendons and ligaments in adolescents, and an impact that would cause a total tear of a major ligament in adults, tends in adolescents to cause an avulsion of the epiphysis. So an impact against the side of the knee joint in children and adolescents may cause an epiphyseal injury, while a similar impact in an adult would tear the medial collateral and anterior cruciate ligaments. When tears of major ligaments are suspected in adolescents, X-rays should be taken so that the epiphyseal cartilages can be checked and any skeletal injuries discovered.The epiphyseal cartilage (growth zone) is weaker than the connective tissue joint capsules, so that dislocations of major joints resulting from accidents are less common than injuries to the epiphyseal cartilage in children and adolescents.

Common fractures
Bone tissue is softer in adolescents than in adults, and the younger the person the less likely it is to break. For this reason, fractures in children show different characteristics (Figure 16.2). The skeleton also has a better blood supply in children than in adults which reduces the time needed for fractures to heal. Treating fractures in children and adolescents involves principles different from those in treating adults.

– The fractures heal better and fewer visible signs remain in children and young people than in adults. An X-ray of a fracture taken 18 months after the injury will show perfect healing and no sign of a fracture in an adolescent, while a change in the shape of the bone is often seen in an adult.
– Fractures heal faster in adolescents than in adults, and therefore children and young people do not have to wear a cast for so long.
– Adolescents sustain different types of fractures from adults. Bones that are still growing are resilient, and can therefore be bent quite vigorously before breaking. An example of this is the ‘greenstick’ fracture, which can occur in the lower arm in children.

Avulsion fractures
In adolescents the strength of the tendons, the ligaments, and the muscles is greater than that of the bones, while this situation is reversed in adults. This means that children and adolescents usually suffer skeletal injuries as a result of accidents or overuse. The bony attachment of the ligament or muscle is torn away from its origin, instead of the muscle or ligament itself tearing. Such avulsion fractures are often located in the growth zones of the flat bones and are most common in the front of the pelvis and also in the ischium where the posterior hamstring muscles have their origins. Avulsion fractures often occur suddenly during hard, rapid loading of the muscles.

When an adolescent has suffered accidental injury, and tenderness, swelling, and effusion of blood are present in the injured area, an X-ray should be taken. If bone attachments have been torn away and displaced to such an extent that they cannot reattach to their original site, surgery should be considered in order to reposition the fragments. A large displacement of the fragment can impair future functioning of the ligaments or muscles if the injury is not treated correctly.
Sometimes it is not fragments of the bone that are torn away but only the periosteum to which the tendon or ligament is attached. This can cause a loss of function in the muscle or ligament, but is not visible on Xray.For this reason, functional testing of muscles and joint stability is of the utmost importance to make the correct diagnosis and choose the correct treatment. Magnetic resonance imaging can be helpful.

An injury caused by avulsion can be more serious than a straightforward rupture of a muscle or tendon, since it has the same implications as fracture. Injuries due to avulsion should therefore be distinguished from the muscle ruptures that often occur in adults who have been subjected to similar violence. Healing times are longer for avulsion fractures than for ruptures of a muscle and can be anything from 1 month to 6 months depending on treatment. It is essential that avulsion fractures are diagnosed at an early stage so that adequate treatment can be started. If these injuries are neglected, the result can be chronic pain and impairment of joint or muscular function resulting in instability or impaired mobility.

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