What is the initial workup and management for a pediatric patient presenting with hip pain without a clear traumatic cause?

From the Guidelines

The initial workup for a pediatric patient with non-traumatic hip pain should prioritize identifying potential life-threatening and limb-threatening conditions, such as septic arthritis, through a combination of clinical evaluation, laboratory tests, and imaging studies. The workup should begin with a thorough history focusing on pain characteristics, fever, recent illness, weight-bearing status, and family history 1. Physical examination should assess gait, range of motion, leg length discrepancy, and perform special tests like the FABER test. Laboratory evaluation should include complete blood count, erythrocyte sedimentation rate, C-reactive protein, and blood cultures if infection is suspected, as these tests can help identify signs of infection such as elevated white blood cell count, erythrocyte sedimentation rate, and C-reactive protein 1.

Initial imaging should start with plain radiographs of the pelvis and affected hip to evaluate for any obvious bony abnormalities or fractures. Ultrasound is particularly useful for detecting joint effusions and can be used as a rapid and non-invasive tool to assess for septic arthritis 1. If further clarification is needed, MRI provides detailed evaluation of soft tissues, bone marrow, and cartilage, and is the most sensitive and specific imaging modality for diagnosing osteomyelitis and septic arthritis 1.

Management depends on the suspected diagnosis but may include rest, non-weight bearing status, NSAIDs such as ibuprofen (10 mg/kg/dose every 6-8 hours) for pain and inflammation, and prompt orthopedic consultation for conditions like septic arthritis, slipped capital femoral epiphysis, or Legg-Calvé-Perthes disease. Septic arthritis requires urgent surgical drainage and antibiotics, as delayed treatment can lead to significant complications including avascular necrosis, growth disturbances, and long-term disability 1. The Kocher criteria, which include fever, erythrocyte sedimentation rate, white blood cell count, and an inability to bear weight on the affected side, can be used to distinguish septic arthritis from transient synovitis, with a higher number of positive criteria indicating a higher likelihood of septic arthritis 1.

Key considerations in the workup and management of pediatric hip pain without a clear traumatic cause include:

• Prompt identification and treatment of septic arthritis to prevent long-term complications
• Use of laboratory tests and imaging studies to guide diagnosis and management
• Consideration of other potential causes of hip pain, such as slipped capital femoral epiphysis and Legg-Calvé-Perthes disease
• Importance of prompt orthopedic consultation for conditions requiring urgent surgical intervention.

From the Research

Initial Workup for Pediatric Hip Pain without Trauma

The initial workup for a pediatric patient presenting with hip pain without a clear traumatic cause involves a meticulous history and detailed clinical examination to guide the radiological investigation in the appropriate direction 2. The age of the child further helps to narrow the differential as certain diseases are more common in certain age groups.

Diagnostic Criteria and Tests

• Clinical examination and simple laboratory tests, such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), are valuable in differentiating between septic arthritis, transient synovitis, and Perthes disease 3.
• Hip ultrasound is a useful tool in detecting hip effusion and guiding aspiration 3.
• Radiographs have a limited role in the primary evaluation of acute hip pain, but may be useful in certain cases 3.
• Magnetic resonance imaging (MRI) and bone scintigraphy can be used for problem-solving, looking for multifocal disease, and staging 2.
• Pelvic MRI should be performed to rule out pelvic osteomyelitis or pyomyositis in children with acute hip pain, elevated ESR (>30 mm/h), and no evidence of septic hip 4.

Common Causes of Hip Pain in Children

• Transient synovitis
• Septic arthritis
• Perthes disease
• Slipped capital femoral epiphysis
• Apophyseal avulsion fractures of the pelvis
• Referred pain from low back or pelvic pathology 5, 6

Laboratory and Imaging Findings

• Elevated ESR (>30 mm/h) is a clinical finding that best predicts pelvic osteomyelitis or pyomyositis 4.
• Hip joint effusion is a common finding in children with hip pain, and can be detected by ultrasound or MRI 3, 4.
• Staphylococcus aureus is a common cause of infection in children with hip pain 4.