The Adolescent Athlete:Special Medical Concerns…

Introduction…

Over 20 million youths between the ages of 6 and 16 years participate in a wide array of community-based organized sports nationwide.

An additional 6 to7 million children are involved in school-sponsored activities.

It is estimated that approximately 3 million injuries occur annually during sports participation among children and adolescents.

Young girls playing organized sports have an estimated rate of 20 to 22 injuries per 100 participants per season, whereas boys are almost twice as likely to be injured, with a calculated risk of 39 injuries per 100 participants per season.

Recent injury data shows that sports and recreational activities account for 32.3% of all serious injuries in children ages 5 to 17 years.

At the youth sport level, there is rarely any involvement by trained medical personnel.

As a result, coaches and parents are often left to provide initial care for injured athletes.

Youth Sport in America

Organized youth sports have been a part of American culture for over a century.

As 19th-century America became increasingly industrialized and urbanized, local schools and churches formed youth sports organizations to help “build character” through physical activity.

In the 1890s, the YMCA first began offering young men the opportunity to compete against each other.

The founding of New York City’s Public School Athletic League in 1903 ushered in the explosion of organized sports participation in the first half of the 20th century, which culminated with the birth of Little League Baseball in 1939.

In the 21st century, concerns continue to be raised about the potential for young athletes suffering physical and emotional harm from sports competition.

Many elementary school athletic programs were disbanded in the 1930s, beginning a shift in philosophy that has had repercussions in youth sports for the past 70 years.

Despite continued opposition and calls for banning competitive leagues, youth sports have never been more popular.

The 1970s saw an influx of girls and young women entering the traditionally male-dominated youth sports culture as barriers were overcome both legally and socially.

The Growing Athlete…Puberty

Before proceeding with a discussion of common injury patterns, an understanding of the uniqueness of the growing athlete is required.

Emotionally and physically, children and adolescents respond far differently to the rigors of sports activity than do their adult counterparts.

Prior to reaching physical maturity, the young athlete’s body is in a dynamic state.

Change is constant as growth and development take place.

Puberty…

Puberty is defined as the time when children develop secondary sexual characteristics, experience an increase in the rate of liner growth, and add muscle mass.

Puberty usually begins at an average of 10 years in girls.At around the age of 12 years, boys will begin puberty.Growth during puberty may account for up to 20% of final

adult height.The average boy will see a doubling of his total muscle

mass between the ages of 10 and 17 years.Puberty may last from between 3 to 6 years.Longitudinal growth accelerates during early puberty, with

peak height velocity being attained at an average of age 12 years in girls and 14 years in boys.

Growth

The longitudinal growth of bones arises from the physis (growth plate) located near the ends of long bones.

Though a rather complex structure, the physis is basically an anatomic framework where rows of a cartilaginous matrix are progressively laid down to allow for longitudinal growth.

Each layer undergoes a series of physiologic transformations, culminating in complete ossification (new bone formation).

All bones continually lengthen beginning with embryonic development, but puberty signals a particularly rapid phase of bone growth.

Bone growth ends once the physis closes, signaling the attainment of skeletal maturity.

The average age of full skeletal development is approximately 14 years for girls and 16 years for boys, but there may be much variation.

The physes, apophyses, and the articular surfaces of long bones are three key anatomic structures susceptible to injury in the young athlete.

All three share the presence of growth cartilage.

The apophysis represents the site at which large muscle-tendon units attach to bones.

Similar in structure to the physis, these tendon sites typically mature and completely ossify prior to the closure of the physes.

The articular cartilage may be more susceptible to stress injury in young athletes, as the surface and underlying matrix have not yet achieved maturity.

Therefore, it is likely unable to attenuate stress as well as the adult tissue.

Skeletal muscle has no corresponding, “growth center” to that found in long bones.

In fact, muscles grow in length in a similar manner as they grow in size—they respond to increasing forces.

The progressive lengthening of the bone stimulates the muscles to correspondingly become longer.

Therefore, muscles lag behind bones in length, setting up for the potential for injury, particularly at times of rapid growth.

Injury Mechanisms

Two basic injury categories are seen in sports.Macrotrauma results from single, high-force

traumatic event. Examples include compound and comminuted fractures, joint

dislocations, and tendon ruptures. Though young athletes may suffer these injuries, they are more

likely to suffer trauma to the growth plate (physis) than to tear a ligament or fracture the shaft of a long bone.

As with any structure, the weakest point is the most susceptible to damage when subjected to a force.

The growth cartilage within the physis offers less resistance than the correspondingly stronger bones and joints.

There is no evidence that organized sports contribute more to macrotraumatic injuries than does free play.

Microtrauma results from chronic, repetitive stress to local tissues. These injuries are increasingly common in children

and adolescents and represent the majority of injuries seen in young athletes.

They are often classified as overuse injuries, typically resulting from repetitive activities such as throwing, swimming, and distance running.

There are multiple factors that lead to these injuries, which will be discussed in more detail throughout the chapter.

Ligament injuries

Severe ligamentous injuries are less common in adolescent athletes than in adults, but they still do occur.

An increased laxity of the ligaments prior to skeletal maturity contributes to this, as does the relative plasticity of the long bones, which may act to absorb some forces, thus attenuating many blows.

As previously discussed, the physis offers less resistance to force than the ligaments and in many instances is the site of injury.

Ligament injuries

For example, if a young athlete suffers a lateral blow to the knee, the valgus force will more likely result in a distal femoral or proximal physis fracture than in the medial collateral ligament (MCL) sprain often seen in skeletally mature athletes.

Interestingly, an increasing body of evidence supports the fact that prior to puberty, ligamentous injuries may occur more commonly than previously thought.

Prior to the pubertal growth spurt, the physis and its attachment site to the underlying bone may actually be stronger than the ligaments.

Ligament injuries…

When evaluating potential ligament injuries in adolescents, the basic principle of comparing the injured joint with the contralateral joint must always be remembered.

The examiner may initially suspect ligamentous disruption owing to the increased laxity of immature joints.

Similar laxity in the contralateral joint confirms a normal finding.

Tendon injuries…

Chronic, microtrauma injuries to the immature apophysis and the resultant inflammation have long been recognized.

Osgood (1903) and Schlatter each described traction injury at the tibial tubercle in 1903.

Other commonly involved sites include the calcaneus and medial humerus.

Apophyseal injuries provide excellent examples of the multiple factors that lead to injury in the growing athlete.

As disussed, muscles lengthen in response to bone growth.

Tendon injuries…

Therefore, a susceptible period exists when the muscle is shorter than necessary for optimal function in relation to the bone.

The result is constant tension on the apophysis, which is exacerbated by repetitive activity.

With repeated traction placed on the apophysis, there may be some weakening within the growth cartilage matrix, culminating in inflammation, pain, and loss of function.

Tendon injuries…

Young athletes are ore susceptible to apophysitis during times of rapid bone growth, but overtraining; poor technique, and chronic misuse all may inflict damaging forces across joints and contribute to injury. Apophysitis is defined as inflammation of the apophysis

High-force injuries may result in the complete disunion of the apophyseal growth cartilage, the adolescent equivalent of a complete tendon avulsion.

Initial treatment of apophyseal injuries is similar to the treatment of other musculoskeletal injuries.

Tendon injuries…

Stretching of the involved muscle groups, changes in activity level, and anti-inflammatory medications may also help.

Calcaneal apophysitis (Sever’s disease) is often particularly emenable to the placement of the heel lift in the shoe of the involved foot.

The heel lift acts to functionally shorten the pull of the gastrocnemius and soleus muscles, lessening the tension at the calcaneal apophysis.

Growth Plate Injuries…

Injuries to the physis may result from microtrauma as well as macrotrauma.

In the 1960s, Salter and Harris classified five injury patterns seen after trauma to the physis.

Growth Plate Injuries…

The Salter-Harris type 1 fracture is by far the most common physis injury and represents a “separation” of the cartilaginous zone.

The diagnosis is most often made based on physical exam findings, because radiographs are typically normal.

Such an injury should always be suspected when the athlete presents with a joint injury, but with tenderness predominantly over the distal or proximal portion of the bone and a normal joint examination.

Injuries to the distal fibula and distal radius are most often seen.

Treatment consist of casting for 4 to 6 weeks, and complications are rare.

Growth Plate Injuries…

Injuries in the Salter-Harris classification become progressively more serious as the corresponding type number increases.

Types III and IV involve fractures of the bone’s articular surface and usually require surgical repair.

Growth Plate Injuries…

Type V injuries represent a compression of the growth plate and carry the highest incidence of premature closure and growth arrest.

Growth Plate Injuries…

Over the years another type of growth plate injury has been recognized.

Chronic, repetitive axial loading of a physis may lead to microvascular injury and resultant growth arrest.

This injury is most commonly seen in gymnasts, who present with radial deviation of their hands secondary to overgrowth of the ulna as compared with the shortened radius.

Growth Cartilage

The articular surfaces of all bones are covered with cartilage.

As well as providing a low-friction articulating surface, cartilage acts to absorb and disperse forces in weight-bearing joints.

Growth cartilage may be somewhat softer than its adult equivalent and subjects the underlying tissues to damage.

Though less common than the two injury patterns mentioned earlier, injuries do occur.

The primary example is osteochrondritis of the radial head capitellum, found in Little League Elbow.

Contributors to Injury

Sports medicine specialist nationwide are in agreement that sports-related injuries among adolescents and children have risen dramatically over the past two decades.

Multiple factors are responsible for the rise and are most easily categorized as intrinsic and extrinsic contributors to injury.

Through multiple factors exist, we will concentrate our discussion on those believed to be most important and amenable to change.

It must also be remembered that many injuries are the result of a combination of factors rather than a single entity.

Intrinsic Factors…

The most important intrinsic factor involved in youth sports injuries is the growing body itself.

The susceptibility to injury of growth cartilage and the decreased flexibility of the muscle-tendon unit represent factors that are under only limited control.