Portal de Periódicos da CAPES

Overuse Injury of the Physis: A “Growing” Problem

2010; Lippincott Williams & Wilkins; Volume: 20; Issue: 5 Linguagem: Inglês

10.1097/jsm.0b013e3181ebb55d

1536-3724

John P. DiFiori,

Shoulder Injury and Treatment

Approximately 27 million children and adolescents between the age of 6 and 17 years participate regularly in team sports in the United States, and an untold several million more are involved in individual sports.1 Beyond the training and competition associated with the “seasonality” of a given sport, increasingly more youngsters are involved in “year-round” sport activity. Driven by the ever-increasing requirements for success in athletics, fuelled at times by parental dreams of collegiate scholarships, and captivated by visions of Olympic medals and professional contracts, many begin to specialize in a single sport at a young age. A focus on a single sport may lead to further intense training with personal coaches, fitness trainers, and attendance at sport-specific and position-specific training camps. Travel teams and club teams, usually with professional coaches and significant budgets funded with players' dues and other fees (no bake sales here!), are well established in many communities and operate in addition to local community-based leagues or high school teams. It is not uncommon for a young athlete to compete on a community-based team (eg, American Youth Soccer Organization) and a club team during the same “season.” As the race for collegiate athletic scholarships heats up in adolescence, some may choose to forgo playing for their high school to continue with a club program that may offer enhanced level and frequency of competition, more sophisticated coaching, and greater exposure to college coaches. Given this environment, it is no surprise that overuse injuries occur with great regularity. Although typical childhood injuries such as the common apophyseal injuries and patellofemoral pain are readily recognized and treated with little long-term sequelae, the bony growth plate, or physis, is a site of overuse injury that can easily be overlooked. Although their prevalence is not known, stress-related injuries involving the physis have been described in a multiplicity of sports including baseball, gymnastics, tennis, soccer, and distance running, among many others. The proximal humerus, distal radius, distal femur, and proximal tibia are the frequently reported sites of injury.2-4 Although extensive scientific data are not available, these injuries would seem to result from more prolonged repetitive loading, not from a simple increase in recent activity as might be seen in more commonly recognized overuse injuries. It is important to appreciate that, in some cases, stress injuries to the physis result in irreversible damage to bone growth.4,5 When diagnosed and treated with an appropriate period of rest, rehabilitation, and education, young athletes can successfully return to athletic activities-ideally in a way that will not result in further overuse injury to the still immature musculoskeletal system. Physeal stress injuries are thought to develop when repetitive loading of the extremity disrupts metaphyseal perfusion. This inhibits ossification of the chondrocytes in the zone of provisional calcification. Widening of the physis then develops as the chondrocytes continue to transition from the germinal layer to the proliferative zone, where they accumulate because they cannot calcify.6 This widening may be diffuse or limited to a focal area of cartilaginous extension into the metaphysis. Widening of the physis may be seen radiographically, whereas physeal cartilage extension has been best identified with magnetic resonance imaging.3,6,7 Most case series and cross-sectional data highlight the association of both training volume and intensity with physeal stress injuries.3,8 Basic science studies have demonstrated inhibition of long bone growth with excessive loading.9 Another key factor is the phase of rapid growth that occurs during adolescence-at this time, the physis is most at risk for both stress and acute injuries. Physeal injuries are more likely to occur during the phase of rapid growth than at any other period.10 A decrease in bone mineral density appears to occur in the 2 to 3 years before peak height velocity in boys and girls that correlates with the period of the greatest incidence of acute physeal fracture, and may also play a role in stress injury of the physis.11 These injuries must always be considered in young athletes experiencing pain during sports activities in the region of a physis-but especially in adolescents in the phase of rapid growth. Physical examination and radiographs may be normal, underscoring the need for a heightened awareness of the injury by all sport medicine practitioners. A magnetic resonance imaging examination can confirm the diagnosis but is usually not necessary. Treatment is straightforward: rest from loading of the extremity. Bracing is rarely needed unless symptoms occur with routine daily activity. Cross training or focusing on other sport-related skills that do not stress the injured site may be recommended to allow the child to remain active and interested. However, the real management “hurdle” is not the technical aspects of diagnosis and treatment but the difficulty in convincing the child, and more frequently the parents, of the need for rest to heal the injury. Discussions about the treatment of such injuries often reveal the motivations of the athlete and parents-motivations that may not always be in concert. The prevention of overuse injuries of the physis involves the same concepts for the prevention of other overuse injuries in children. Moderating activities to avoid excessive volume and intensity (particularly during the adolescent growth spurt), scheduled periods of rest, time away from sport, and delaying single-sport specialization are basic tenets. Educating parents and coaches not to ignore complaints of pain is important. Many may not consider that an injury can be present in a child who is describing pain yet is able to continue training and competing without apparent limitations. In summary, injuries to the physis are a form of overuse injury caused by prolonged repetitive stress usually over a period of many months. Clinicians should add this to their differential in the young athlete with activity-related pain because the symptoms and findings can be limited. Identifying and addressing the expectations of parents and other adults that often fuel the extensive and intense participation leading to these injuries is a more difficult challenge, but it is the key to ensuring an appropriate recovery and a return to healthy sport participation.