PRACTICE RECOMMENDATIONS
• Use radiographs to identify bone changes from disease (as well as fracture) when evaluating a limp. C
• Consider growth plate injuries as well as toddler’s fracture; both may be radiographically occult and require immobilization for treatment. C
• Consider child abuse if the patient has an isolated mid-shaft tibial fracture. C
• Assess for fever, elevated sedimentation rate, elevated C-reactive protein, and leukocytosis when radiographs are unrevealing or when a patient has systemic symptoms associated with limp. These factors are predictors of septic arthritis. B
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
A mother brings her 4-year-old son to the office because he has been limping. She isn’t aware of a specific trauma. But the boy and his twin brother, while recovering from “colds,” were rough-housing in their room when this son complained of pain. He is afebrile and points to his knee as the area of pain.
Although limping in children is common—the incidence is roughly 2 per 10001—it is never normal. It indicates pain, weakness, or structural abnormality.2 Most cases result from trauma.1 Limp usually resolves with little intervention and no sequelae. However, the differential diagnosis is broad and daunting (TABLE 1), and some causes of limp are associated with significant morbidity.
TABLE 1
Possible causes of limp in a child1-3,17
| Traumatic/mechanical Fractures, stress fractures Muscle injuries Sprains/strains Contusions Developmental dysplasia of the hip Slipped capital femoral epiphysis Tarsal coalition Child abuse Overuse injuries Leg length discrepancy |
| Infectious Septic arthritis Osteomyelitis Lyme disease Psoas abscess Diskitis |
| Inflammatory Transient synovitis Juvenile rheumatoid arthritis Ankylosing spondylitis Reiter syndrome Lupus |
| Vascular Legg-Calve-Perthes disease Osteonecrosis Hemoglobinopathies (sickle cell disease) |
| Neoplastic Leukemia, lymphoma Malignant/lytic tumors (Ewing sarcoma, osteogenic sarcoma, etc.) |
| Metabolic Rickets Hyperparathyroidism |
| Neuromuscular Muscular dystrophy Cerebral palsy Peripheral neuropathy |
Helpful tips for your initial assessment
Many textbook authors have described some causes of limp as “painless.” However, truly painless limp is rare, seldom acute, and usually the result of mechanical or neuromuscular disorders.1 A more likely explanation for acute “painless” limp is that a young child with pain is unable to express pain or accurately identify its location. Further, the child may instinctively avoid painful positions or movements and, thus, may present only with decreased movement of an extremity or refusal to bear weight.3
With a child who has knee pain, remember the pediatrics maxim: “Knee pain equals hip pain,”3 underscoring the diagnostic difficulty with limp.
Also bear in mind that children of different ages tend to have different etiologies of limp (TABLE 2). For example, septic arthritis, osteomyelitis, and transient synovitis occur more commonly in children under 10 years. Legg-Calve-Perthes disease and leukemia are more common in children between the ages of 4 and 10. Slipped capital femoral epiphysis (SCFE) is more common in boys over the age of 11.
TABLE 2
Common causes of limp according to child’s age1
| < 3 years | 3-10 years | 11-18 years |
|---|---|---|
| Foreign body | Legg-Calve-Perthes disease | Juvenile arthritis |
| Osteomyelitis | Osteomyelitis | Slipped capital femoral epiphysis |
| Septic arthritis | Septic arthritis | Trauma (physeal fracture) |
| Toddler’s fracture | Transient synovitis | Tumor |
| Transient synovitis | Trauma (physeal fracture) | |
| Tumor | Tumor |
Fracture
Fracture is a possibility across all age ranges, necessitating radiographs if suspected. Beyond detecting fractures, x-ray films can identify bony changes associated with disease (eg, Legg-Calve-Perthes disease, SCFE). Radiographs can also identify a clinically significant joint effusion at the hip.4 However, x-ray results may be falsely negative for some fracture types.
Salter-Harris Type I fractures are transverse fractures through the growth plate with epiphyseal separation from the metaphysis.5 Typical findings are a history of trauma and point tenderness over the epiphyseal plate. Type I fractures are radiographically occult, making the injury easy to mistake as a sprain. Nonetheless, growth plate injuries are common in children, requiring immobilization.
Toddler’s fracture was first described as a spiral, oblique undisplaced fracture of the distal tibial shaft in children from 9 months to 3 years of age.6 It results from a rotational or twisting force through the tibia while the leg rotates internally on a planted foot.7,8 This is the most common tibial fracture in infants and young children.9 The incidence has been reported as 0.6 to 2.5 per 1000 pediatric visits.10 Accurate diagnosis is important because current treatment recommendations suggest a long leg cast for 3 to 5 weeks, followed by a short leg cast for a total of 6 weeks.11
Despite being the most common tibial fracture, toddler’s fracture is easily missed. Initial radiographs are only 53% sensitive.7,10 This implies that nearly 50% of children with tibial fracture will have an initially negative x-ray result. However, nearly 94% of children with a confirmed toddler’s fracture have been unable to bear weight.12 Evidence suggests that despite negative radiographs, patients with point tenderness over the tibia and an inability to bear weight should be treated for presumed toddler’s fracture.12