Orthopedic Injuries and Growing Pains
Sara T. Stewart, MD, MPH, FAAP
A 6-year-old boy has a 1-week history of leg pains. He wakes up at night and cries because his legs hurt; however, during the day he is fine, with no pain and no movement limitations. He has no history of trauma, fever, or joint swelling. The family history is negative for rheumatic or collagen vascular disease. The boy’s height and weight are at the 50th percentile for age, he is afebrile, and the physical examination is unremarkable.
1. What is the differential diagnosis of leg pains in school-age children?
2. What laboratory or radiographic studies are appropriate for children with leg pains?
3. How do musculoskeletal injuries in children differ from those in adults (eg, injury type, injury location)?
4. How does the physician decide the extent of the diagnostic workup in a child with extremity pain?
5. What fractures are commonly seen at different ages?
Children by nature are active and explorative. They routinely experience cuts, scrapes, minor injuries, and pain. Because primary care physicians are often the first to examine children with injuries, they play an important role in making the preliminary diagnosis and assessing the need for further evaluation and treatment. The more common complaints and injuries seen in pediatricians’ offices are discussed in this chapter: growing pains, radial head subluxation (ie, nursemaid’s elbow), and fractures, including growth plate injuries. Evaluation of children with limp is discussed in Chapter 118.
The term “growing pains” is somewhat misleading, because no evidence exists that these pains are associated with growth. The period of middle childhood, when growing pains are diagnosed, is not the period of most rapid growth in the child. “Leg aches” or “idiopathic leg pain” may be better terms for the pains, but growing pains is the most widely used term.
The prevalence of growing pains is not well defined, but it is estimated to be between 15% and 30% of all children. These pains most commonly occur in children between 4 and 14 years of age, and girls are affected more frequently than boys.
Nursemaid’s elbow, or radial head subluxation, is the most common joint injury in childhood. It occurs most commonly in children 1 to 4 years of age, with a peak incidence between 2 and 3 years of age. Other ligament and tendon injuries are relatively uncommon in prepubertal children because of the relative strength of these structures in comparison to the growth plate of the adjacent developing bone. Most commonly, fractures involving the growth plate occur before ligamentous injury. With the exception of pulled elbow, joint dislocations and ligamentous injury in children usually are the result of significant trauma.
Trauma and injury are significant causes of morbidity and mortality in childhood. Injuries are the most common reason for hospitalization in children and adolescents younger than 18 years and are the leading cause of death after age 1 year. Musculoskeletal problems account for 15% of all injuries and most commonly occur in the upper extremity. Fractures are perhaps the most common significant form of musculoskeletal injury in children who present to physicians for evaluation and treatment.
Children with growing pains typically present with a history of intermittent, poorly localized pain in the bilateral lower extremities that occurs at night over a long period. The pain most commonly involves the calves and anterior thighs, never the joints. Symptoms usually resolve within several minutes, and in the morning the child has normal activity.
Subluxation of the radial head is characterized by a sudden onset of elbow pain associated with the traumatic event and subsequent decreased use of the arm. At the time of presentation for medical care, a child with this injury typically appears well, aside from a refusal to use the affected arm. The child typically holds the arm close to the body with the elbow in slight flexion and the forearm pronated. Usually, no gross deformity, swelling, or overlying skin trauma is evident, and the child typically refuses to supinate the forearm during examination. Point tenderness may be elicited laterally over the radial head.
Obvious deformity or lack of spontaneous movement in the extremity in question is strongly indicative of an underlying fracture. Localized swelling, tenderness, and limited range of motion all may be signs of a fracture.
Figure 116.1. Nursemaid’s elbow. The sudden traction on the outstretched arm pulls the radius distally, causing a tear in the annular ligament at its attachment to the radius. A portion of the ligament becomes trapped within the joint as the traction is released and the arm recoils. A, Mechanism of injury. B, Pathology. C, Method of reduction (ie, hyperpronation).
Growing pains are recurrent aches or pains localized most commonly to the muscles of the legs and occasionally to the muscles of the arms of children. The pain is located deep within the extremity and not in the joints. Etiology remains unclear. Emotional and psychological stress, a low pain threshold, bone fatigue, and myalgia secondary to exercise or physical activity all have been implicated as possible contributory factors. Approximately one-third of patients also report recurrent headaches or abdominal pain.
Nursemaid’s elbow is subluxation of the radial head caused by rapid and forceful extension and pronation of the forearm. This mechanism most commonly occurs when caregivers pull a child toward themselves and the child resists, wanting to go in the other direction. As illustrated in Figure 116.1, the subluxation occurs as the result of tearing of the annular ligament, with trapping of the ligament between the radius and the capitulum humeri. This injury occurs primarily in young children, because the ligamentous attachment to the bone becomes thicker with age and growth.
Because of anatomic and physiologic differences between children and adults, such as the presence of a cartilaginous growth plate, thicker periosteum, and increased plasticity of the skeleton in children, fracture patterns in children often are different from those in adults. Additionally, fractures may influence long-term growth and development of the affected limb in a growing child.
Fractures are classified based on anatomic location, type of fracture, and degree of angulation or displacement. Fracture location may be described as diaphyseal, metaphyseal, or epiphyseal/growth plate depending on the portion of the bone involved (Figures 116.2 and 116.3). Fractures may be open or closed. In closed fractures, the skin over the fracture site is intact, whereas in open fractures, the skin is broken. In cases in which 2 bone fragments are displaced relative to each other, the direction and degree of displacement are based on the distal fragment.
The Salter-Harris classification is used most commonly to classify growth plate injury (Table 116.1, Figure 116.4). Approximately 15% of all fractures in children involve the growth plate. Type 1 and 2 fractures are the most common fractures involving the growth plate. Type 3 and 4 fractures involve the epiphysis and are considered to be intra-articular. Type 5 fractures are uncommon and are caused by a crush injury to the growth plate. With type 1 and 5 fractures initial radiographs may appear normal because bone fragments are not displaced. Because of involvement of the growth plate, any injury of the physis is associated with risk of growth arrest. The risk is variable, however, depending on the type of injury.
Figure 116.2. Anatomy of a long bone.
Figure 116.3. Non-epiphyseal plate fractures.
Figure 116.4. Salter-Harris classification of epiphyseal plate fractures.
Table 116.1. Long Bone Fracture Patterns That Occur in Children
|Nonepiphyseal Plate Fractures|
|Complete||Both sides of the bone fractured; type depends on direction of fracture line|
|Transverse||Perpendicular to long axis of the bone|
|Oblique||At an angle to long axis of the bone|
|Spiral||Zigzag course around the bone|
|Comminuted||Fractures with ≥3 fragments (rare in children)|
|Buckle or torus||Bone compression causes it to bend or buckle rather than break; occurs at junction of metaphysis and diaphysis|
|Greenstick||Cortex broken on tension side but intact on compression side|
|Bowing||Deformation of bone caused by bending without fracturing|
|Classic metaphyseal lesion||Fracture of distal, poorly mineralized metaphysis, perpendicular to long axis of bone; previously termed bucket-handle or chip fracture|
|Epiphyseal Plate Fractures (Salter-Harris Classification)|
|Type 1||Horizontal fracture through the physis|
|Type 2||Fracture through the physis, extending into the metaphysis|
|Type 3||Fracture through the epiphysis, extending into the physis|
|Type 4||Fracture through the epiphysis, physis, and metaphysis|
|Type 5||Crush injury of the physis|
Box 116.1. Common Causes of Leg Pain in Children
•Idiopathic leg pains
•Soft tissue injury
•Soft tissue abscess
•Malignant bone tumors (eg, osteosarcoma, Ewing sarcoma)
•Metastatic disease (eg, lymphoma, neuroblastoma)
Benign Bone Lesions
•Langerhans cell histiocytosis
•Juvenile rheumatoid arthritis
Other Musculoskeletal Causes
•Slipped capital femoral epiphysis
•Transient synovitis of the hip
•Patellofemoral stress/ chondromalacia patellae
•Generalized ligamentous laxity and joint hypermobility
•Sickle cell disease pain crisis