In a child with a limp that occurs after trauma, localized radiographs or radiographs of the tibia on the affected side are most likely to reveal the diagnosis.
Consider hip pathology in a child with a limp and knee or thigh pain.
Suspect septic arthritis in a child with fever, painful limp, elevated C-reactive protein (CRP) >2 mg/dL or erythrocyte sedimentation rate (ESR) >40, and a white cell count >12 × 109/L.
In a child presenting with a limp and without a history of trauma, fever, or systemic symptoms, obtain a hip ultrasound followed by radiographs if the ultrasound is negative.
A magnetic resonance imaging (MRI) should be performed early in the diagnostic process if infection is a possible cause for a limp in a child.
A history of trauma and the presence of fever are important symptoms to consider when ordering an expanded diagnostic workup for a limp.
A limp is a jerky, uneven, or laborious gait, usually caused by pain, weakness, or deformity. The development of a child’s gait is important to identify the etiology of a limp. Children begin to crawl at 9 months, independently walk at 12 to 15 months, and run at 18 months. At 1 year of age, the normal infant has a broad-based gait and moves the limbs rapidly with short steps with the arms flexed and without reciprocal arm movement. The foot makes contact with the ground all at once. By 3 years most adult kinematic patterns are developed. With subsequent changes in velocity and step length, an adult gait pattern is achieved at 7 years. The adult gait consists of a stance phase and a swing phase. The stance phase (60% of the gait cycle) begins when the heel of one foot strikes the ground and bears all the weight, advances to a foot flat position during midstance, and progresses to pushoff by the toes as weight gets transferred from the heel to the forefoot. The swing phase begins when the opposite foot pushes off the ground; the leg is swung forward with the foot clearing the ground until the heel makes contact with the ground. The most common cause for a limp is trauma; Table 109-1 lists other causes. The differential diagnosis is influenced by the duration and type of limp, age of the child, and the anatomic site affected.
TABLE 109-1Conditions that Cause Limping in a Child ||Download (.pdf) TABLE 109-1 Conditions that Cause Limping in a Child
Fracture (Salter–Harris, toddler, stress, avulsion, buckle)
Soft-tissue injury (contusion, strain, sprain, tendonitis, insect bite, foreign body)
Apophysitis (Sever, Osgood–Schlatter, Köhler, Freiberg)
Soft-tissue infections (cellulitis, abscess)
Arthritis (septica, gonococcal, Lyme disease)
Epidural abscess of the spinea
Tuberculosis of bone
Bone tumors—malignanta (osteosarcoma, Ewing ...