Secondary Logo

Journal Logo

Competitive Sports: Section Articles

Musculoskeletal Overuse Injuries in the Pediatric Population

Magrini, Danielle DO, FAAP, CAQSM1; Dahab, Katherine S. MD, FAAP, CAQSM2

Author Information
Current Sports Medicine Reports: 11/12 2016 - Volume 15 - Issue 6 - p 392-399
doi: 10.1249/JSR.0000000000000303
  • Free

Abstract

Introduction

The benefits of exercise and sport are vast. For young athletes, sports participation improves physical fitness, enhances self-esteem, improves peer socialization, and improves academic performance (5,19,63). In today’s sports vernacular, terms, such as burnout, overtraining, and overuse injuries, conditions once thought to only occur in elite athletes, have become more mainstream (8,71). Data acquisition and surveillance, through systems such as the National High School Sports-Related Injury Surveillance System, High School Reporting Information Online (high school RIO), an Internet-based sports injury surveillance tool, have made specific classification and quantification of injuries in youth athletes possible. These systems have allowed us to discern a rise in gender-specific overuse injuries within high school athletes, the timing of which varies with gender (8,62). Historically, overuse injuries are underreported, so this increase may be due to better reporting strategies. Athletic trainers, the main mode of entry of athletic injuries into high school RIO, only report those injuries that result in lost playing time (62). If an athlete is continuing to play through an injury, it is likely to bypass the registry and thus go unreported. High school RIO only captures high school athletes and, by design, does not account for the millions of other youth athletes in club or recreational leagues. Furthermore, not all sports are represented through the surveillance program. This deficit is beginning to improve with time and the increased utilization of high school RIO across the United States. Even with these limitations, the trends that can be extrapolated from this data are impactful and support better understanding of the patterns of injury in this population. Overall, there is a lack of high-quality data sets relating to pediatric musculoskeletal overuse injuries, necessitating further studies (8).

It is estimated that nearly 30 million children in the United States participate in an organized team sport each year. The National Council of Youth Sports survey found that 60 million children ages 6 to 18 yr participate in some form of organized athletics, with nearly 44 million participating in more than one sport (56). Children are more consistently playing sports year-round. There may be inadequate rest periods when there is an early commitment and specialization to a single sport. Though there is a paucity of new research regarding specific overuse injuries or treatments in children, recent literature has trended toward identifying risk factors, both intrinsic and extrinsic, including early sports specialization (ESS), and how such risk factors may contribute to overuse injuries in youth athletes (19). Recent studies also have addressed variations within specific sports, gender differences related to injury patterns, and possible preventative measures (62,67,68). In this article, we will review some of these newer studies as well as some of the most common pediatric overuse injuries seen in clinical practice.

Definition and Intrinsic Risk Factors

Overuse injuries are typically related to repetitive, submaximal, physiologic stress, and loading of the musculoskeletal system without giving the body sufficient time to recover (19). Each results in tissue adaptation. Though such adaptation can be beneficial, detrimental tissue injury can ensue when ongoing stressors are coupled with inadequate rest (19). Anatomical growth and development, flexibility, age, sex, and BMI may all be factors that play a role in perpetuating overuse injuries in athletes.

Early Anatomical Differences

Young athletes may be intrinsically vulnerable to overuse injuries, most notably at the skeletal physeal-epiphyseal junction and at any number of tendinous-bone junctions or apophyses (58,72). Mixing these dynamically maturing areas with periods of intense training and inadequate rest theoretically could result in an additive effect promoting overuse injuries. These dynamically changing areas have shown tensile strength variability in laboratory studies examining the architecture of both bovine and human growth plate areas (58,72). The physeal zone is composed of multiple layers, and recent research suggests that the region made up of enlarging hypertrophic chondrocytes could be an area of inherent weakness (10,27,58). There also could be a relative decrease in bone mineralization and bone mass just before peak bone growth velocity, which may contribute an additive fracture risk during this perimaturation period (24). These variables could possibly explain the gender-related and injury timing differences among adolescent injuries in high school athletes (62).

Flexibility

Bony growth is accompanied by a lag in muscular and tendinous elongation, resulting in decreases in flexibility. Whether decreases in flexibility promote overuse or acute injuries is unclear. Further studies are needed to decipher if there is a true causal relationship (25). The association between gender and flexibility has been studied, and the link between gender variability and injury patterns is currently being examined in further detail (3). Generalized joint hypermobility (GJH) is not a static component of the physical examination. Fluctuations in GJH over various periods of growth and development are pertinent findings, though further longitudinal studies are needed to confidently assign an association with injury patterns (44). The usage of the Beighton’s score for hypermobility can be a clinically useful tool to assess the extent of a patient’s hypermobility. The impact of hypermobility on a patients’ risk for injury remains unclear in the pediatric population.

Age and Gender

Age and gender differences are known to play a role in the incidence and location of overuse injury. Stracciolini et al. (66) examined these factors among the pediatric population, dividing their sample into 2 subclassifications: a preadolescent and an adolescent subgroup. Their retrospective chart review compared injury patterns in young children ages 5 to 12 yr versus adolescents ages 13 to 17 yr. Overall, the lower extremity was the most commonly injured bodily area across both age groups. In the preadolescent subgroup, injuries were roughly equally distributed between the overuse and traumatic classifications. In the adolescent subgroup, however, significantly more patients were classified as overuse injuries when compared with acute or traumatic injuries.

One of the largest studies to date, led by Schroeder et al. (62), sourced an extensive dataset from high school RIO. Injuries among 20 sports across 100 randomly chosen high schools across North America were included in their retrospective surveillance study. A total of 2,834 overuse injuries were reported during 18,889,141 athletic events (AEs), equating to a rate of 1.50 per 10,000 AEs. Within their sample, girls had a higher incidence rate at 1.88 injuries per 10,000 AE versus 1.26 in boys.

Age and development within the context of gender also play an important role. Although the proportion of overuse injuries appear equally distributed throughout high school, girls exhibit a higher and greater proportion of injuries at an earlier part in their high school career when compared with boys (Fig. 1) (62). Girls generally reach their pubertal growth time about 2 yr earlier than boys, which may account for these subtle yet significant statistical findings (19,62). The sports most commonly resulting in injury were girls’ track and field and field hockey. The lowest overuse injury rates occurred in boys’ volleyball and boys’ ice hockey. It is important to remember, however, that these data only include overuse injuries, excluding acute traumatic injuries (62).

F1
Figure 1:
Timing of overuse injuries in male and female high school athletes. (Reprinted from Schroeder AN, Comstock RD, Collins CL, Everhart J, Flanigan D, Best TM. Epidemiology of overuse injuries among high school athletes in the United States.

BMI

Yard and Comstock’s (74) data in high school athletes demonstrate that BMI impacts the incidence and type of injuries that young athletes experience. Nearly two thirds (61.4%) of injured high school athletes were normal weight. The prevalence of overweight and obesity was highest among injured football athletes (54.4%). Compared with normal weight athletes, obese athletes sustained a larger proportion of knee injuries. Compared with normal weight athletes, underweight athletes sustained a larger proportion of fractures.

Extrinsic Risk Factors

Extrinsic risk factors also can play a role in the development of overuse injuries in young athletes. Such factors may include incorrect training technique, higher training volumes, and ESS (19,52).

Early Specialization

ESS, a recently evolving concept in the field of sports medicine, also may play a crucial role in the growing number of injuries both overuse, acute, and a combination of both (19,41). Questions still remain about what constitutes the true definition of “early specialization” as well as the sport-specific variables of “intense” training. There is likely a significant degree of intersport and age variability, and ongoing studies are currently focused on exploring these factors and variables (19,41). The theory originally put forth by Ericsson and colleagues back in the 1990s stated that 10,000 h of “deliberate” work in one particular area raises one’s likelihood of success. This concept was originally extrapolated from studies of elite musicians, and its’ applicability and relatability to sport is still questionable (21,22). The literature found that musicians who specialized at an early age, early being 5 yr or younger, with a deliberate amount of practice volume did seem to achieve more success than their counterparts who began after age 5 yr and had less intense focus and time allotted to their art form (41). Although data quality is inconsistent and likely susceptible to intersport variability, studies in athletes exhibit more of an inverse relationship between elite status and onset of specialization. In retrospective reviews of elite athletes, the majority focused their effort on a single sport at a later age and few specialized before age 12 yr. The sample size for these data is small, as very few athletes go on to compete at the elite or world class and Olympic level. As a result, these studies are inherently under-powered.

The Training of Young Athletes (TOYA) study examined the factors that influence young British athletes, ages 8 to 17 yr, to increase their level of training or specialize in one particular sport. Results suggest that coaches are the primary influence (65%), whereas parental influences are a close second at 57% (7). The study is limited by a sample that was not able to consider all sports, including only swimming, tennis, gymnastics, and soccer. Lower socioeconomic status patients also were underrepresented.

Clinical anecdote supports an increase in year-round sport activity among young athletes. It is increasingly common to encounter, for instance, a young soccer player who plays competitively for multiple seasons each year, possibly on several competitive teams. Many youth athletes lack a true “off season” and have little time reserved for structure-free, recreational play (41). The rising trend of yearlong sport appears to be associated with several negative outcomes.

In studies of youth athletes participating in soccer and tennis, those who were allowed more time in unstructured recreational play had a higher rate of sport progression when compared with those with strict formalized practices (26,41). Those that specialized earlier and had less structure-free play were more inclined to become injured or discontinue their sport due to burn out (41). In a retrospective analysis, Jayanthi et al. found that injured athletes are more likely to be older than uninjured athletes and, overall, spent more hours per week involved in structured play. Of those injured, the majority was due to overuse injuries (67.4%). When correcting for age and hours spent training, their data suggest that specialization confers a dose-dependent risk of injury (42).

Further studies confirm the findings of Jayanthi et al. and also note an increased risk aphophyseal injuries of the lower extremity, especially Osgood-Schlatter disease (OSD) and Sinding-Larsen-Johansson (SLJ) syndrome, which appear at a four times greater incidence in those athletes who specialized in a single sport (34).

Clinical Pearls

When caring for a pediatric athlete, a thorough history and physical examination is critical. A thorough medical history should include the athlete’s schedule and commitments to academic-affiliated and club/league activities.

A determination of pubertal status as well as graphical growth parameters through the use of the U.S. Centers for Disease Control and Prevention’s (CDC) growth charts is important in assessing intrinsic risk factors facing the athlete.

The physical examination should address joints above and below the area in question, as referred pain may be a part of the underlying clinical picture. A complete examination of the area/joint in question should include an assessment of the dynamic and static stabilizers and anatomical landmarks within the region in question. A neuromuscular examination, including perfusion, sensation, and motor function, also is pertinent.

Radiographic studies should be considered to support or refute the history and physical examination components. Comparative views of the contralateral side can be helpful when anatomical variants are unclear as either the source of the pathology versus being a normal variant in maturation. Open physes and apophyses should be noted. Further imaging, including magnetic resonance imaging (MRI) or computed tomography (CT), should be carefully considered when highly specific data are necessary for management.

If the injury is deemed as overuse, either from inadequate rest and/or due to modifiable risk factors, a trial of conservative management with rest and activity modification is almost always the first-line therapy. Removing the stress from the growing physis and/or apophysis frequently allows for adequate healing. Once pain levels improve, physical therapy can be initiated to augment musculoskeletal imbalances and to improve factors, such as flexibility and balance. Some athletes may complete such programs at home, whereas others may require a more formal or structured approach.

Upper Extremity Injuries

The overhead athlete such as the swimmer, baseball pitcher, tennis player as well as those athletes that extensively weight bear through the upper limbs, such as gymnasts, may seek out medical care for upper extremity overuse injuries.

Any alteration in biomechanics, training schedule, training equipment, or other factors, both intrinsic and extrinsic, can result in injury through repetitive athletic exposures.

Little League Shoulder (Proximal Humeral Epiphysiolysis)

The proximal humeral physis is a vulnerable area and can be prone to overuse injuries, particularly in baseball pitchers between the ages of 11 and 16 yr (46,59). The proximal humeral physis contributes approximately 80% of the longitudinal growth of the humerus and usually fuses between 19 and 22 yr of age (48). In boys, a period of rapid growth typically occurs between ages 11 and 14 yr, and there is direct correlation with this growth period and incidence of injury to the area (48).

Overhead throwing can be divided into a series of phases with variations in anatomical positioning and resultant force distribution seen throughout each phase. Consistent traction across the proximal humeral physis, and specifically the application of rotational torque, can stress and even result in microfractures across the hypertrophic zone of the physis resulting in injury (48).

Typical complaints made by the athlete include pain and increasing fatigue of the arm, which may manifest as loss of speed or decrease in overall accuracy (46,59). Examination findings include pain with direct palpation of the humeral physis, especially laterally. There may be some limitations in range of motion and pain with resisted range of motion testing, especially external rotation (46,59). Patients with this injury should be examined for disproportionate range of motion in internal compared with external shoulder rotation in both the dominant and nondominant arms as discrepancies are usually readily apparent. Scapular dyskinesis, posture, and truncal/core abdominal strength also should be examined and considered as potential areas of weakness affecting the overall kinetic chain of motion.

Quantifying pitch counts per day and week, as well as knowing the other field positions, if any, the player is rotating through, can help confirm the theory of an overuse injury. Eliciting whether the athlete plays year-round, on one team versus multiple teams, is crucial to understanding the origin of the injury.

Radiographic analysis can be normal or may display widening of the humeral physis, depending on the chronicity of the insulting injury (36). If there is any question, a contralateral radiographic view of the uninvolved side can be obtained and used as a comparative control (36). In a majority of cases, additional studies are not required because classically the diagnosis is clinical. The x-rays can be helpful in helping the clinician verify that there is no other confounding injury in the extremity.

Once diagnosed, the athlete will require a period of complete rest from throwing, usually lasting 6 wk or until pain significantly improves or resolves (36). Rehabilitation, after a period of rest, is critical to correcting certain imbalances that may have contributed to the initial injury pattern. The focus of therapy should include normalizing range of motion, muscular strength especially scapulothoracic, trunk, pelvic, and glutes. A gradual return to pitching protocol with implementation of proper mechanics and strict adherence to pitch counts can be invaluable in reducing the incidence of repeat injury.

Little League Elbow (Medial Epicondyle Apophysitis)

The pediatric elbow can be vulnerable to overuse because it has six ossification centers which appear and close at different ages of skeletal maturity as well as multiple muscle and ligamentous attachments. The repetitive motion of throwing, for example, can transfer high volumes of valgus-type forces through these immature growth centers or apophyses resulting in microtraumatic or even macrotraumatic insults (47,48). The centers that withstand the most impact from these valgus stresses include the medial epicondyle, ulnar collateral ligament, and the flexor-pronator mass with its associated apophysis (75). The medial epicondyle first originates at about 5 to 6 yr of age and fuses by about 14 to 16 yr in males and is the attachment site for the common tendon of the wrist flexors. In fact, the medial epicondyle is usually the last apophysis in the elbow to fuse (32,47,48). Anatomically, the medial collateral ligament (MCL) of the elbow is a three-part structure made up of anterior, posterior, and oblique bundles. The anterior band, which originates on the medial epicondyle of the humerus, is primarily responsible for stabilizing the elbow during valgus stress positions (32).

During the physical examination, pain over the medial epicondyle is the most common complaint. Range of motion may be limited secondary to pain and guarding by the patient. During muscle testing, there may be pain with resisted wrist flexion and forearm pronation and pain, possibly laxity, with valgus stress. The clinician should apply valgus stress through an arch of motion from flexion at 90 degrees to near neutral extension when possible. Special tests, such as milking maneuver, also can be very helpful for the clinician. Tinels’ test and assessment of the neurovascular elements of the entire upper extremity also will be key in ruling out other confounding pathology.

Diagnosis is usually clinical; however, x-rays can be helpful to look at the bony integrity of the elbow, the appearance of the apophysis itself, and to look for any other abnormalities. The x-rays are usually normal or may demonstrate early widening or fragmentation of the medial epicondyle apophysis (75). Any significant displacement may require a consultation with a pediatric orthopedic surgeon for operative repair, though surgery is rarely needed for a chronic overuse injury.

If the injury can be managed conservatively based on clinical examination and x-rays, rest and discontinuation of all provocative maneuvers for at least 4 to 6 wk or until pain levels abate is necessary to reduce inflammation at the apophysis and adjacent soft tissue structures (46). Most of the time, the player is able to continue involvement in cardiovascular conditioning and some skill work, such as batting, if asymptomatic. He or she should not be throwing and pitching during the rest stage.

Once the athlete becomes pain-free, physical therapy will be essential in strengthening and rebuilding proper throwing mechanics before commencing a gradual return to pitching protocol. Pitch counts also should be adhered to, and ample downtime for recovery between practices and competition is vital to preventing reoccurrences or new injury patterns.

Gymnast Wrist (Distal Radial Epiphysitis)

Epiphysitis of the distal radius can be the source of pain in athletes who frequently bear weight through their upper extremities. With upper extremity weight-bearing activities, the distribution of forces across the wrist can amount to nearly twice one’s body weight. These forces are being transferred across the distal physes, predominantly the radial physis and, to a lesser extent, the ulnar physis. On a repetitive basis, compressive and shearing forces become more than a young athlete’s growing body is able to withstand, especially in the context of inadequate rest. Multiple authors report that wrist injuries in gymnasts are increasing in frequency, ranging anywhere from 50% to 80% of participants, with variations based on age and competitive status (13,53).

Caine and colleagues (9) reported higher injury rates in peri-pubertal female gymnasts at Tanner stages 2 and 3 compared with those more immature at Tanner stages 1 and those who were more mature at Tanner stages 4 and 5, regardless of level of competition. DiFiori and colleagues (18) also found similar results in female gymnasts when analyzing wrist pain over a 1-yr period. Athletes between the ages of 5 and 16 yr were studied and in those ranging from 10 to 14 yr, 73% reported pain and had a much higher overall incidence of injury than those younger than 10 yr or older than 14 yr, even after adjusting for training regimes and years in the sport. DiFiori and colleagues (18) also reported that floor exercise, the pommel horse, and the balance beam are the routines most associated with wrist pain.

Physical examination of the wrist is usually notable for tenderness over the distal radial physis. Associated areas of pain including the Triangular Fibrocartilage Complex (TFCC), the scapholunate junction and the metacarpal heads should lead the clinician toward associated injuries (20). Typically, range of motion of the wrist is normal.

Initial x-rays may demonstrate widening of the distal radial physis. Occasionally a MRI (± arthrogram) may be obtained for further assessment or for atypical presentations. Advanced imaging will confirm widening of the physeal region with thickened cartilage in the zone of provisional calcification and increased signal adjacent to the physis on both the metasphyseal and epiphyseal borders (20). The weakest portion of the physis is this hypertrophic layer adjacent to the zone of provisional calcification due to lack of a reinforcing collagen matrix (60). There is typically a paucity of bony edema because this injury is less likely acute and more likely due to repetitive microinsults to the region.

Conservative treatment includes a period of rest from weight-bearing activities, bracing of the wrist, and physical therapy. If left untreated, the repetitive loading could result in premature closure of the distal radius physis. This premature closure and shortening of the radius can continue to progress and lead to significant bone deterioration, instability, and chronic wrist pain secondary to arthritis (4,46).

Common Lower Extremity Overuse Injuries

Traction Apophysitis

Young athletes are vulnerable to lower-extremity apophysitis during times of rapid growth and development from the same general underlying anatomical theories seen in the upper extremities. The three areas in the lower extremity that are most commonly affected include the calcaneus, the tibial tubercle, and the inferior pole of the patella. A description of each of these areas will be described in more detail below.

Calcaneal Apophysitis (Sever’s Disease)

Calcaneal apophysitis presents clinically as heel pain in the active and growing child, with a peak incidence between ages 8 and 13 yr. Cleated athletes and gymnasts tend to be the most susceptible, though any young athlete can develop this overuse injury. The pain is often localized to the calcaneal apophysis, which runs from the medial to the lateral aspect of the posterior calcaneus and is the insertion point of the Achilles’ tendon (12,70). Symptoms tend to wax and wane with activity levels, typically improving with rest. The “calcaneal squeeze test,” performed by squeezing the medial and lateral aspects of the calcaneal apophysis, is pathognomonic. The diagnosis is clinical, and os calcis x-rays are typically normal.

Common treatment includes relative rest from activity, posterior chain stretching with particular attention to the heel chords and hamstrings. Gel heel cups may be used in shoes and cleats. Ice and nonsteroidal anti-inflammatory drugs (NSAIDs) may be helpful in the acute inflammatory stage of the disease. As symptoms improve, patients may gradually return to activity while maintaining a regular stretching protocol. Failure to improve with conservative treatment requires further investigation for other causes of pain, including calcaneal stress fractures.

Tibial Tubercle Apophysitis (OSD)

Repetitive microtrauma at the insertion of the patellar tendon into the tibial tubercle resulting in a traction apophysitis is commonly known as OSD (28). It was first described by two orthopedic surgeons in 1903. More recently, data published through the use of ultrasound, CT, and MRI studies demonstrate a dual component of apophyseal inflammation and possible degeneration of the patellar tendon resulting in tendonitis and occasion thickening of the tendon, and not just an isolated inflammation of the apophysis (61,69).

The etiology of OSD is likely multifactorial (55). It is more common to see symptoms during periods of rapid growth, especially the prepubertal growth phase that occurs usually 1 to 1.5 yr before puberty onset (49). It is suggested that the bony constituents tend to elongate more expeditiously than the soft tissues, and this asynchronous growth may create increased tension at the tendinous-bony junctions. OSD is more common in males than females and in those who are active in sports, especially running, jumping, and cutting sports (15,49).

The diagnosis of OSD is clinical. Radiographic studies are rarely needed unless physical examination findings suggest other etiologies.

Unfortunately, there are no double-blinded, randomized controlled studies evaluating for definitive treatment of OSD (28). Most physicians prescribe a host of conservative measures, including stretching, strengthening, NSAID, ice, and occasionally iontophoresis (28,45). Infrapatellar bracing, such as a cho-pat strap, may be beneficial in relieving some of the pressure directed at the insertional point of the tibial tubercle apophysis. Education will prepare the patient for the self-limited nature and natural fluctuations in symptomatology of this overuse injury.

Apophysitis at the Inferior Pole of the Patella (SLJ Disease)

Much like OSD, SLJ is most often seen in the rapid growing prepubescent child. SLJ disease is characterized by pain at the inferior pole of the patella secondary to repetitive traction of the patellar tendon. (39) Like OSD, SLJ disease tends to have a predilection for males between the ages of 10 and 14 yr of age, though it classically is seen before OSD (12,51,73).

Radiographs may demonstrate of fragmentation of the pole, though a normal study does not exclude a diagnosis of SLJ. The apophysis of the inferior pole of the patella must be open and present to make the diagnosis. Traction apophysitis, when present, can result in the deposition of calcium at the proximal attachment of the patellar tendon (39).

Treatment is conservative and includes stretching, strengthening, icing, and limiting activity as needed for symptomatic relief. An infrapatellar tendon strap or cho-pat strap can be worn during activity to help alleviate symptoms.

Pelvic and Back Injuries

Hip Apophysitis

The pelvis of a young athlete is full of open apophyses, which are prone to both acute and overuse injuries (Fig. 2). The tendon, muscle, and ossified bone are all much stronger than the dynamically evolving, part cartilaginous apophysis.

There are seven major sites of large muscle attachments in the pelvis, and these are usually the most common areas of involvement for both tendonitis and apophysitis based on the age and ossification closure status of the patient. Some of the sites, such as the ischial spine, for example, may not fully fuse until the mid 20s, making this area a potential source of apophysitis well past adolescence (36). Having a keen understanding of the anatomy can help the clinician in completing a proper examination and special tests that can isolate certain muscles and muscle groups. At the anterior superior iliac spine is the attachment of the sartorius. At the most superior part of the pelvis, the iliac crest, is the origin of the tensor fascia latae, and the insertion of the abdominal muscles, specifically the internal and external obliques and the transverse abdominis. At the anterior inferior iliac spine is the origin of the rectus femoris. At the greater trochanter is the insertion of the glute maximus and medius, piriformis, and the hip rotators. At the ischial tuberosity is the origin of the hamstrings. At the lesser trochanter is the insertion point for the iliopsoas and lastly at the body of the pubis and inferior pubic ramus is the origin of the adductors and gracilis (30,36).

Once a pelvic apophyseal injury is diagnosed, rest, removal of the repetitive forces through the injured area, and occasionally a period of non-weight-bearing are necessary for healing. Without proper attention and rest, these apophyseal areas may become widened and even progress to acute and sudden avulsion injuries (36).

F2
Figure 2:
Pelvic apophyses in the young athlete. Reprinted with permission from Ann & Robert H. Lurie Children’s Hospital of Chicago.

Spondylolysis and Spondylolisthesis

Back pain in athletes is concerning for a spondylolysis and/or spondylolisthesis, especially in those who perform repetitive hyperextension of the spine. The incidence of adolescent spondylolysis is in the range of 8% to 15 %. Of adolescent athletes who seek care for their low back pain, about 50% of them will have a spondylolysis (11,36,54,65). Athletes at high risk for such injuries include gymnasts, divers, wrestlers, weight lifters, throwing athletes, and even rowers, though any athlete could potentially develop this injury (65). Spondylolysis is a pars interarticularis fracture(s) of the vertebral arch and can be unilateral or bilateral. The pars portion of the bone is the weakest part of the neural arch, and with repetitive stress and mechanical loading through hyperextension maneuvers, the bony elements fatigue much like the mechanism behind a stress fracture elsewhere in the body (2,65).

Patients often present with focal low back pain that may or may not radiate to the buttock or proximal lower extremities (65). Weakness of the lower extremities, change in sensation, changes in bowel or bladder function are not classically seen, and should raise concern for a more serious injury or condition.

Physical examination commonly demonstrates tight hamstrings and increased lumbar lordosis, particularly in those with low back pain or spondylolysis (11,65). A stork test, whereby the patient stands in a single-leg stance and hyperextends may be positive. This test, however, is nonspecific and also can be positive in other etiologies of low back pain (11,65).

The textbook “scotty dog” sign may be seen on oblique X-rays, and if a spondylolysis is present, there may be a lucency or fracture line seen through the dog’s neck or collar area. Initial x-rays may be negative, which does not rule out a spondylolysis, and advanced imaging may be necessary (65).

Even with negative x-rays, a high index of suspicion should lead a clinician to obtain a low-dose radiation CT, MRI, or even a bone scan to see if a stress reaction or true stress fracture is present. With bilateral pars fractures, there is a possibility for anterior slippage of the vertebrae resulting in spondylolisthesis. This typically happens within the first 6 to 8 wk of the injury and is much more common in the adolescent population before age 16 yr (50). After age 16 yr, perhaps due to a more mature bone complex, less anterior slippage or lithesis is seen. Farfan and colleagues (23,50) denoted that during bone maturation the weakest site between two vertebrae may be the growth zone which is closely associated with the vertebral endplate and the intervertebral disc. This separation at the epiphyseal site may be the reason why this pediatric population is more prone to undergo spondylolisthesis. Single-photon emission computed tomography (SPECT) CT, and MRI are all good modalities used in the diagnosis of spondylolysis/lithesis, and it partly becomes user preference and experience as to which modality is chosen by the clinician. Radiation is a major consideration with both SPECT and CT, perhaps leading to the increased use of MRI.

Once an athlete is diagnosed with either a spondylolysis or a spondylolisthesis, the majority of activities, especially those that load the vertebral column, must cease. A period of relative rest eliminating ballistic movements while maintaining low-impact cardiovascular exercise that is pain-free is ideal. Rehabilitation and physical therapy focusing on back, core, and pelvic floor strengthening exercises as well as hamstring flexibility is an important part of the recovery process. Back braces for treatment are still controversial. The Boston Overlap Brace demonstrated good results with improved pain scores as well as favorable clinical outcomes in 80% of their adolescent athletes who were diagnosed with spondylolysis (17). Further studies defining the absolute indications for bracing, type of brace, and duration of use in these injuries are needed.

Conclusions

Overuse injuries in children are common, especially rapidly growing peripubescent and adolescent athletes. The increasingly competitive nature of youth sports, ESS, and year-round participation with inadequate periods of rest, appear to contribute to the rising prevalence of overuse injuries in the pediatric population. Pediatricians, sports medicine physicians, and orthopedic surgeons should be aware of the evolving landscape of musculoskeletal complaints.

Conveying the importance of rest and the potential harm of continuous activity on the actively growing body is essential to helping the patient understand how and why pathology occurs. Although further research is warranted to explore the causative and associated factors of overuse injury, the rising epidemic has triggered consensus and clinical guidelines. The American Academy of Pediatrics’ Council on Sports Medicine and Fitness encourages athletes to take 1 to 2 d of rest per week and 2 to 3 months of rest per year away from sport-specific training to transition to more free, recreational play (2). Current recommendations state that specialization in one sport should be delayed until late puberty to optimize success, protection from injury, and longevity in the sport itself (8,19).

The authors declare no conflict of interest and do not have any financial disclosures.

References

1. af Ekenstam FW, Palmer AK, Glisson RR. The load on the radius and ulna in different positions of the wrist and forearm. A cadaver study. Acta Orthop. Scand. 1984; 55:363–5.
2. Afshani E, Kuhn JP. Common causes of low back pain in children. Radiographics. 1991; 11:269–91.
3. Allison KF, Keenan KA, Sell TC, et al. Musculoskeletal, biomechanical, and physiological gender differences in the U.S. military. U.S. Army Med. Dep. J. 2015:22–32.
4. Bak K, Boeckstyns M. Epiphysiodesis for bilateral irregular closure of the distal radial physis in a gymnast. Scand. J. Med. Sci. Sports. 1997; 7:363–6.
5. Baranowski T, Bar-Or O, Blair S, et al. Guidelines for School and Community Programs to Promote Lifelong Physical Activity Among Young People. Available from: http://www.cdc.gov/mmwr/preview/mmwrhtml/00046823.htm.
6. Bates DG, Hresko MT, Jaramillo D. Patellar sleeve fracture: demonstration with MR imaging. Radiology. 1994; 193:825–7.
7. Baxter-Jones AD, Maffulli N; TOYA Study Group. Parental influence on sport participation in elite young athletes. J. Sports Med. Phys. Fitness. 2003; 43:250–5.
8. Brenner JS; American Academy of Pediatrics Council on Sports Medicine and Fitness. Overuse injuries, overtraining, and burnout in child and adolescent athletes. Pediatrics. 2007; 119:1242–5.
9. Caine D, Cochrane B, Caine C, et al. An epidemiologic investigation of injuries affecting young competitive female gymnasts. Am. J. Sports Med. 1989; 17:811–20.
10. Carter SR, Aldridge MJ, Fitzgerald R, et al. Stress changes of the wrists in adolescent gymnasts. Br. J. Radiol. 1988; 61:109–12.
11. Cassas KJ, Cassettari-Wayhs A. Childhood and adolescent sports-related overuse injuries. Am. Fam. Physician. 2006; 73:1014–22.
12. Chang GH, Paz DA, Dwek JR, et al. Lower extremity overuse injuries in pediatric athletes: clinical presentation, imaging findings, and treatment. Clin. Imaging. 2013; 37:836–46.
13. Chawla A, Wiesler ER. Nonspecific wrist pain in gymnasts and cheerleaders. Clin. Sports Med. 2015; 34:143–9.
14. Dalton SE. Overuse injuries in adolescent athletes. Sports Med. 1992; 13:58–70.
    15. de Lucena GL, dos Santos Gomes C, Guerra RO. Prevalence and associated factors of Osgood-Schlatter syndrome in a population-based sample of Brazilian adolescents. Am. J. Sports Med. 2011; 39:415–20.
    16. Demirag B, Ozturk C, Yazici Z, et al. The pathophysiology of Osgood-Schlatter disease: a magnetic resonance investigation. J. Pediatr. Orthop. 2004; 13:379–82.
      17. d’Hemecourt PA, Zurakowski D, Kriemler S, et al. Spondylolysis: returning the athlete to sports participation with brace treatment. Orthopedics. 2002; 25:653–7.
      18. DiFiori JP, Benjamin HJ, Brenner JS, et al. Overuse injuries and burnout in youth sports: a position statement from the American Medical Society for Sports Medicine. Br. J. Sports Med. 2014; 48:287–8.
      19. DiFiori JP, Puffer JC, Aish B, et al. Wrist pain in young gymnasts: frequency and effects upon training over 1 year. Clin. J. Sport Med. 2002; 12:348–53.
      20. Dwek JR, Cardoso F, Chung CB. MR imaging of overuse injuries in the skeletally immature gymnast: spectrum of soft-tissue and osseous lesions in the hand and wrist. Pediatr. Radiol. 2009; 1:1310–6.
      21. Ericsson KA, Krampe RT, Heizmann S. Can we create gifted people? Ciba Found. Symp. 1993; 178:222–31.
      22. Ericsson KA, Krampe R, Tesch-Romer C. The role of deliberate practice in the acquisition of expert performance. Psychol. Rev. 1993; 100:363–306.
      23. Farfan HF, Osteria V, Lamy C. The mechanical etiology of spondylolysis and spondylolisthesis. Clin. Orthop. Relat. Res. 1976:40–55.
      24. Faulkner RA, Davison KS, Bailey DA, et al. Size-corrected BMD decreases during peak linear growth: implications for fracture incidence during adolescence. J. Bone Miner. Res. 2006; 21:1864–70.
      25. Feldman D, Shrier I, Rossignol M, et al. Adolescent growth is not associated with changes in flexibility. Clin. J. Sport Med. 1999; 9:24–9.
      26. Ford PR, et al. The role of deliberate practice and play in career progression in sport: the early engagement hypothesis. High Abil. Stud. 2009; 20:65–75.
      27. Frush TJ, Lindenfeld TJ. Peri-epiphyseal and overuse injuries in adolescent athletes. Sports Health. 2009; 1:201–11.
      28. Gholve PA, Scher DM, Khakharia S, et al. Osgood Schlatter syndrome. Curr. Opin. Pediatr. 2007; 19:44–50.
      29. Gottsegen C, Eyer B, White E, et al. Avulsion fractures of the knee: imaging findings and clinical significance. Radiographics. 2008; 28:1755–70.
        30. Grady MF, Goodman A. Common lower extremity injuries in the skeletally immature athlete. Curr. Probl. Pediatr. Adolesc. Health Care. 2010; 40:170–83.
        31. Gray H, Clemente CD, et al. Gray’s Anatomy of the Human Body. Philadelphia: PA. Lea and Febiger, 1985, pp. 283–4.
          32. Gregory B, Nyland J. Medial Elbow injury in young throwing athletes. Muscles Ligaments Tendon J. 2013; 3:91–100.
          33. Guler F, Kose O, Koparan C, et al. Is there a relationship between attention deficit/hyperactivity disorder and Osgood-Schlatter disease? Arch. Orthop. Trauma Surg. 2013; 133:1303–7.
            34. Hall R, Foss K, Hewett T, et al. Sports specialization is associated with an increased risk of developing anterior knee pain in adolescent female athletes. J. Sport Rehabil. 2015; 24:31–5.
            35. Hirano A, Fukubayashi T, Ishii T, et al. Magnetic resonance imaging of Osgood-Schlatter disease: the course of the disease. Skeletal Radiol. 2002; 31:334–42.
              36. Hoang QB, Mortazavi M. Pediatric overuse injuries in sports. Adv. Pediatr. 2012:359–83.
              37. Hosea T, Hannafin J, Bran J, et al. Aetiology of low back pain in athletes: role of sport type. Br. J. Sports Med. 2011; 45:352.
                38. Hosea TM, Hannafin JA. Rowing injuries. Sports Health. 2012; 4:236–45.
                  39. Iwamoto J, Takeda T, Sato Y, et al. Radiographic abnormalities of the inferior pole of the patella in juvenile athletes. Keio J. Med. 2009; 58:50–3.
                  40. Jayanthi NA, Pinkham C, Durazo-Arivu R, et al. The risks of sports specialization and rapid growth in young athletes. Clin. J. Sports Med. 2011; 21:157.
                    41. Jayanthi N, Pinkham C, Dugas L, et al. Sports specialization in young athletes: evidence-based recommendations. Sports Health. 2013; 5:251–7.
                    42. Jayanthi N, LaBella C, Fischer D, et al. Sports-specialized intensive training and the risk of injury in young athletes. Am. J. Sports Med. 2015; 43:794–801.
                    43. Johansson S. En forut ioke beskriven sjukdom i patella. Hygiea. 1922; 84:161–6.
                      44. Junge T, Larsen LR, Juul-Kristensen B, Wedderkopp N. The extent and risk of knee injuries in children aged 9–14 with generalised joint hypermobility and knee joint hypermobility—the CHAMPS-study Denmark. BMC Musculoskelet. Disord. 2015; 16:143.
                      45. Kabiri L. Evaluation and conservative treatment for Osgood-Schlatter disease: A critical review of the literature. Int. J. Ther. Rehabil. 2014; 21:91.
                      46. Kinsella S, Carl R. Upper extremity overuse injuries. Clinical Pediatric Emergency Medicine. 2013; 14:318–26.
                      47. Klingele KE, Kocher MS. Little league elbow: valgus overload injury in the paediatric athlete. Sports Med. 2002; 32:1005–15.
                      48. Kocher MS, Waters PM, Micheli LJ. Upper extremity injuries in the paediatric athlete. Sports Med. 2000; 30:117–35.
                      49. Kujala U, Kvist M, Heinonen O. Osgood-Schlatetter’s disease in adolescent athletes. Am. J. Sports Med. 13(4): 236–40.
                      50. Leone A, Ciantoni A, Cerase A, et al. Lumbar spondylolysis: a review. Skeletal Radiol. 2011; 40:683–700.
                      51. López-Alameda S, Alonso-Benavente A, López-Ruiz de Salazar A, et al. Sinding-Larsen-Johansson disease: analysis of the associated factors. Revista Española de Cirugía Ortopédica y Traumatología. 2012; 56:354–60.
                      52. Malina RM. Early sport specialization: roots, effectiveness, risks. Curr. Sports Med. Rep. 2010; 9:364–71.
                      53. Mandelbaum BR, Bartolozzi AR, Davis CA, et al. Wrist pain syndrome in the gymnast. Pathogenetic, diagnostic, and therapeutic considerations. Am. J. Sports Med. 1989; 17:305–17.
                      54. Micheli LJ, Wood R. Back pain in young athletes: significant differences from adults in causes and patterns. Arch. Pediatr. Adolesc. Med. 1995; 149:15–8.
                      55. Nakase J, Goshima K, Numata H, et al. Precise risk of Osgood Schlatter disease. Arthroscopy And Sports Medicine. 2015; 135:1277–128.
                      56. National Council of Youths Sports Report on Trends and Participation in Organized Youth Sports. 2008 [cited 2015 May 1]; Available from: http://www.ncys.org/pdfs/2008/2008-ncys-market-research-report.pdf.
                      57. Ogden JA. Skeletal Injury in the Child, 3rd edition. 2000;194–6.
                        58. Ogden JA, Beall JK, Conlogue GJ, et al. Radiology of postnatal skeletal development. IV. Distal radius and ulna. Skeletal Radiol. 1981; 6:255–66.
                        59. Osbahr DC, Kim HJ, Dugas JR. Little league shoulder. Curr. Opin. Pediatr. 2010; 22:35–40.
                        60. Poletto E, Pollock A. Radial epiphysitis (aka gymnast wrist). Pediatr. Emerg. Care. 2012:484–5.
                        61. Rosenberg ZA, Kawelblum M, Cheung YY, et al. Osgood-Schlatter lesion: fracture or tendinitis? Scintigraphic, CT, and MR imaging features. Radiology. 1992; 185:853–8.
                        62. Schroeder AN, Comstock RD, Collins CL, et al. Epidemiology of overuse injuries among high-school athletes in the United States. J. Pediatr. 2015; 166:600–6.
                        63. Seefeldt V, Ewing M. Youth sports in America: an overview. Available from: https://www.presidentschallenge.org/informed/digest/docs/199709digest.pdf.
                        64. Sinding-Larsen MF. A hithero unknown affection of the patella in children. Acta Radiol. 1921; 1:171–3.
                          65. Standaert CJ, Herring SA. Spondylolysis; a critical review. Br. J. Sports Med. 2000; 34:415–22.
                          66. Stracciolini A, Casciano R, Levey Friedman H, et al. Pediatric sports injuries: an age comparison of children versus adolescents. Am. J. Sports Med. 2013; 41:1922–9.
                          67. Stracciolini A, Casciano R, Levey Friedman H, et al. Pediatric sports injuries: a comparison of males versus females. Am. J. Sports Med. 2014; 42:965–72.
                          68. Stracciolini A. A closer look at overuse injuries in the pediatric athlete. Clin. J. Sport Med. 2015; 25:30–5.
                          69. Topol G, Podesta LA, Reeves KD, et al. Hyperosmolar dextrose injection for recalcitrant Osgood-Schlatter disease. Pediatrics. November 2011; 128(5).
                          70. Weiner DS, Morscher M, Dicintio MS. Calcaneal apophysitis: simple diagnosis, simpler treatment. J. Fam. Pract. 2007; 56:352–5.
                          71. Wiersma, Lenny D. Risks and benefits of youth sport specialization: perspectives and recommendations. Pediatr. Exerc. Sci. 2000:13–22. Available from: http://www.humankinetics.com/acucustom/sitename/Documents/DocumentItem/12188.pdf.
                          72. Williams J. Tensile properties of the physis vary with anatomic location, thickness, strain rate and age. J. Orthop. Res. 2001; 19:1043–8.
                          73. Wilson J, Rodenberg R. Apophysitis of the lower extremities. Contemp Pediatr. 2011. Available from: http://contemporarypediatrics.modernmedicine.com/contemporary-pediatrics/news/modernmedicine/modern-medicine-feature-articles/apophysitis-lower-extre?id=&sk=&date=&pageID=2.
                          74. Yard E, Comstock D. Injury patterns by body mass index in U.S. high school athletes. J. Phys. Act. Health. 2011; 8:182–91.
                          75. Zellner B, May MM. Elbow injuries in the young athlete—an orthopedic perspective. Pediatr. Radiol. 2013; 43:129–34.
                          Copyright © 2016 by the American College of Sports Medicine