Overuse Injuries

Many of the sports related visits to our offices are made because of injuries that occur over time, that is overuse injuries, as opposed to violent collision injuries, which have an obvious cause. More and more of the children we treat are involved in competitive sports and are at risk for these overuse injuries. The following article addresses the most common of these injuries and gives the proper rehabilitation schedules as well as preventative guidelines.

By Chris G. Koutures, MD adapted from Contemporary Pediatrics November 2001

Overuse injuries have become common as more and more children participate in sports. A careful history can identify risk factors; targeted patient education can lead to successful rehabilitation and prevent injuries. Thanks to the growing number of young people participating in sports at an early age, training year-round, and competing at specialized or elite levels, the incidence of overuse injuries has risen in the past decade. Recent studies estimate that 30% to 50% of pediatric sports injuries are caused by overuse, with the frequency of injury equal among boys and girls. For older patients, the proportion of injuries that are due to overuse is even higher.

Ideally, children should participate in sports for one reason-to have fun. Along with that fun should come the pride of acquiring and mastering new skills in a social environment. Regrettably, lack of fun is often a leading reason for dropping out. Understanding both the intrinsic and extrinsic demands placed on the young athlete can help identify risk factors for overuse injuries.. Always maintain a high level of suspicion for problems caused by overuse. Even the most innocent-appearing injury may have elements of overuse.

The problem defined
In simple terms, overuse injuries can be defined as the product of "too much, too fast, too soon." How much is too much? How fast is too fast? How soon is too soon? The answers vary from athlete to athlete.

A program that overtaxes one participant may be acceptable to another of the same age and ability. Certain characteristics, however, can clue you in to possible over training or overuse. Mild discomfort or soreness after physical activity, rating no higher than 2 or 3 on a pain scale of 0 to 10, is common. If pain exists during activity, or if pain after activity rates higher than 3, that activity is perhaps "too much," "too fast," or "too soon" for that particular athlete. 6

The use of ice and nonsteroidal anti-inflammatory drugs (NSAIDS such as Motrin or Advil) immediately after exercise is common. But the need for increasing amounts of ice or NSAIDS, or the need to use them for a longer duration, should raise the suspicion of overuse. If pain or soreness causes changes in gait, body mechanics, or sport technique, this too may suggest overuse. Other signs of a possible problem include diminished success or enjoyment in sports participation and changes in mood, peer relations, or school and work performance.

Children should never "play through" any pain or disability. Regrettably, because they fear being removed from activity or disappointing parents and coaches, many young athletes continue painful activities. Parents and coaches must learn to temper their desire to "let the child continue to play" and seek early and appropriate care to prevent long-term consequences. When any athlete is experiencing pain, he or she should stop exercising and begin rehabilitation. Rehabilitation of any injury follows a three-step process (Table 1). During this process, focus on what the athlete can do rather than what the athlete can't do. Complete cessation of activity is often unnecessary and unlikely to be followed by a child athlete committed to his sport.

The absence of finite participation limits for young athletes is a growing risk factor for overuse injuries. While 6- to 9-year-olds may have developed important visual, balance, motor, and learning skills that allow for organized sport participation, there is a growing tendency to push such young athletes toward sport specialization and training regimens suited for more mature athletes. Children under 10 years should avoid specializing in one sport and participate in a variety of activities with other children who are appropriately matched in age, ability, and interest.

Shoulder and elbow problems
Experience indicates a direct relationship between the number of pitches thrown or time spent swimming a week and shoulder or elbow pain. Specific recommendations regarding age and number of pitches thrown or frequency and duration of swimming have been developed (Tables 2 and 3) and should be followed precisely. All pitches or meters count, whether in games or competition, in practice, playing with friends, or in private lessons.

Because the throwing motion involves both the shoulder and elbow, there may be elbow problems in shoulder injuries and shoulder problems in elbow injuries. Remember that shoulder and elbow pain are not limited to pitchers. Other high-volume throwing positions include catcher and shortstop. Be extremely suspicious of injury in a pitcher who plays these other positions when not on the mound.

The goal of exercise is to apply repetitive submaximal loads to connective tissue, muscle, and bone to build strength and endurance. Because the beneficial aspects of exercise actually take place during the recovery phase, adequate rest is essential to allow tissue to adapt and undergo further activity without injury.

Patients should have at least two full rest days a week, with a minimum of two rest days immediately after a pitching performance. This advice may be contrary to participation in weekend tournaments-staples of youth sports in which athletes are often required to perform several times in a two- or three-day period. Excessive demand and insufficient recovery result in tissue microtrauma with release of vasoactive substances, inflammatory cells, and enzymes that create clinical symptoms of pain, weakness, and diminished range of motion.3

In overhead sports, too much activity leads to fatigue of the supporting rotator cuff muscles, allowing for increased movement of the humeral head within the shoulder joint. In early phases of overuse, pain is vague and noted only with activity. Further progression leads to more sharp, localized pain during activity and at rest (Table 4). Besides pain, signs of shoulder or elbow weakness include decreased accuracy, endurance, and throwing velocity. Technical errors such as "dropping the elbow" during the acceleration phase of throwing or the out-of-water recovery and catch phases of freestyle swimming can also lead to fatigue of rotator cuff muscles.

Because of the valgus stresses placed on the elbow in throwing motion, athletes under 14 years of age, who have immature ligament and tendon attachments to the medial epicondyle apophysis, are at greater risk of injury than older athletes. Growth of the longitudinal bone occurs sooner than that of ligament, muscle, or tendon, creating an imbalance that places undue stress on the immature cartilage of these apophyseal attachment sites.

Back Pain
Back pain in a child or adolescent must be taken seriously.

Frequent back extension (heading a soccer ball, gymnastics, line play in football) places axial loads that stress the posterior elements of the lumbar column, often leading to stress injury of the pars interarticularis, most often at L5.

Optimally, athletes should take at least one week off between seasons. Many do not heed this recommendation.

The spectrum of lumbar region injury runs from a pre-stress reaction (lumbar pain without true fracture) to frank unilateral or bilateral spondylolysis (true stress fracture of the pars), culminating in spondylolisthesis (anterior motion of a lumbar segment relative to the next distal segment).

Spondylolysis often presents as midline lower lumbar pain of insidious onset with gradual worsening. Extension or rotation of the lumbar region often exacerbates the pain. Radiation of pain to the lower extremities or other neurologic symptoms suggests alternate diagnoses.

Radiologic imaging and subsequent management of suspected spondylolysis are controversial. Additional imaging studies, such as single-photon-emission computerized tomography (SPECT) scans or CT scans, may be indicated to determine acuity and delineate fracture pattern, respectively. Therefore, referral to spine specialists is highly recommended.

Rehabilitation strategies include bracing to limit lumbar extension, abdominal strengthening, and hamstring flexibility (see the discussion of knee pain in the following section). Often, athletes must refrain from at-risk activity for at least three to six months.

Leg Pain
Runners with leg pain often suffer from one of three entities: anterior knee pain, shin pain, or Achilles tendon and heel pain. These can be the cumulative result of increases in midseason training that overtax young athletes.

In general, the intensity, duration, and frequency of training should not be increased by more than 10% in a given week. So, a runner who runs 20 miles a week should run no more than 22 miles the next week at the same pace without adding hills or sprint work.

Table 5 lists specific age-based recommendations for maximum running distances.

Multiple minor injuries or repeated injuries to the same area are signs of inadequate rest and rehabilitation. The highest risk factor for subsequent injury is incomplete rehabilitation of a primary injury. Athletes with first-time injuries should therefore diligently rehabilitate before returning to play.

Special attention must be paid to a history of stress fractures anywhere in the body. In a female athlete, such a history may be the only obvious sign of the female athlete triad of osteoporosis, menstrual irregularities, and an eating disorder.16 Although no athlete is immune from the consequences of inadequate nutrition, a young woman who participates in an endurance activity or "appearance" sport such as figure skating and gymnastics is at particular risk.2

Substantial physical activity coupled with inadequate caloric and protein intake can lead to primary amenorrhea (no sexual development by 14 years of age or no menarche by 16 years) or secondary amenorrhea (three or more months between periods or fewer than six periods in 12 months). Such "athletic" amenorrhea is a diagnosis of exclusion made only after complete evaluation and exclusion of other causes. The consequences of amenorrhea include decreased circulating estrogen levels, leading to osteopenia or osteoporosis with an increased risk of stress fracture.

Active youth, particularly adolescents undergoing a growth spurt, often have astounding caloric needs-as many as 4,500 kcal/d.17 Aside from optimal caloric intake, the most crucial nutritional issues surround adequate calcium, iron, protein, and fluid intake (Table 6).

 

Anterior knee pain
In immature athletes, frequent knee extension can lead to traction apophyseal injury with local tenderness at secondary growth centers of the distal patellar pole (Sinding-Larsen-Johansson disease) and the tibial tubercle (Osgood-Schlatter disease).

Postactivity ice massage to these painful areas can be of great benefit. Patellofemoral pain syndrome (PPS) can affect an athlete of any age. It is characterized by complaints of vague pain around or underneath the patella that worsens with prolonged running, standing, or sitting in a chair. Swelling and frank instability are uncommon, though the patient may feel that the knee "collapses" due to the anterior knee pain. The exact mechanism of PPS is uncertain, but many believe that malalignment of the patella about the distal femur is the main problem. Weak or uncoordinated quadriceps muscles, especially the vastus medialis oblique (VMO), can lead to abnormal lateral movement of the kneecap or excessive contact of the patellar undersurface with the femur, both leading to pain.

Tight hamstrings can be a root cause of anterior knee pain by placing greater resistance on the extensor mechanism. Increasing hamstring flexibility is the cornerstone of rehabilitation. VMO strengthening can help in some cases. Correction of hyperpronation (see the discussion under shin pain that follows) can also help alleviate symptoms. Ice and NSAIDs can be used to reduce inflammation and discomfort.

Shin pain
Repetitive eccentric contractions of the foot dorsiflexors during heel strike in running can lead to medial tibial stress syndrome (so-called shin splints), an inflammatory condition of the tibialis posterior and soleus muscle aponeurosis-periosteal interface at the medial border of the tibia. With this syndrome, there is no numbness or tingling in the lower leg or foot.

Further along the continuum are tibial stress fractures, most frequently found on the medial border of the distal tibia. Whereas shin splint pain is usually diffuse and occurs on the medial border of the tibia and the surrounding soft tissue, pain from a tibial stress fracture tends to be focal (the athlete can often identify the painful area with the tip of a finger) and localized more toward the tibial spine than toward the surrounding soft tissue. Another differentiating factor is that activity actually reduces the discomfort of shin splints, while repeated impact activity intensifies the pain of a tibial stress fracture.

Most cases of shin splints and tibial stress fractures are non-emergent; the exceptions are patients who have focal pain localized to the proximal tibial spine. Because stress fractures of the anterior tibial cortex are more likely than other fractures to become complete fractures, patients with such focal pain should be placed on non-weight-bearing status and immediately referred for orthopedic consultation.

Although plain radiographs have sub optimal sensitivity for stress fractures, they remain the method of choice for initial investigation. Standard views include anterior-posterior, lateral, and bilateral oblique views of the tibia and fibula. Periosteal elevation and cortical irregularities are common "soft" findings in suspected stress fractures. Triple-phase bone scans have greater sensitivity and specificity for both medial tibial stress syndrome and stress fractures, and are often part of specialty consultation. Treatment includes limiting impact activities such as running and jumping and using medial arch supports to correct hyperpronation. Nonimpact endurance activities such as biking, swimming, or pool-running (in which the person wears a floatation vest that allows a running motion while "floating" in the pool) are excellent alternatives during the healing phase. Ice massage on the painful regions can help ease the discomfort of shin splints.

Achilles tendon and heel pain
The Achilles tendon has been termed "the thermometer of the runner"-when a light squeeze produces pain, the runner has almost certainly been overtraining. Achilles tendinosis is caused by chronic overload of the gastrocnemius and soleus muscles during push-off, resulting in degenerative changes within the collagen substance of the tendon. This condition is usually seen in more mature adolescent and adult athletes. Athletes between 8 and 12 years are more apt to have Sever disease, focal tenderness and inflammation of the Achilles tendon insertion (rather than the tendon itself) into the apophyseal region of the calcaneus.

Radiographic examination is usually not indicated. The recovery period can be prolonged, with treatment focused on stretching of the Achilles and the initial use of heel cups or wedges to reduce the impact on the Achilles-calcaneus insertion. Ice massage to the body or calcaneal insertion of the Achilles tendon can be beneficial, and NSAIDs can reduce pain and swelling.

The opportunity for prevention
Overuse injuries are a growing component of a general pediatric practice. A careful history and evaluation can often identify root causes and provide the opportunity to offer the athlete tips on rehabilitation and injury prevention. Focusing on more common conditions characterized by overuse (Table 7) can help guide the initial evaluation and treatment while reducing morbidity in an active population.