What are the red flags for hip pain that require immediate medical attention?

Red Flags for Hip Pain Requiring Immediate Medical Attention

Hip pain accompanied by any red flag signs or symptoms requires immediate medical attention to rule out serious pathology that could lead to significant morbidity or mortality.

Critical Red Flags

Serious Underlying Conditions

• Infection: Fever, severe pain, inability to bear weight, erythema, warmth 1
• Fracture: History of trauma, inability to bear weight, deformity 1, 2
• Tumor: Night pain, unexplained weight loss, pain unrelated to activity 1
• Vascular issues: Sudden onset of pain with pale/cool extremity 2

Pediatric-Specific Red Flags

• Slipped Capital Femoral Epiphysis (SCFE): Adolescents with hip/knee pain, especially if obese 1, 3
• Perthes' Disease: Children with limping and limited hip motion 1
• Septic arthritis: Children with fever and refusal to bear weight 4
• Referred pain from appendicitis: Right-sided hip pain with abdominal symptoms 4

Physical Examination Red Flags

• Inability to bear weight on the affected limb
• Severe limitation in range of motion
• Joint effusion with warmth and erythema
• Neurovascular compromise (decreased pulses, sensation, or motor function)
• Deformity of the hip joint 1, 2

Imaging Considerations for Red Flag Symptoms

Initial Imaging

• Radiographs should be the first imaging test for any concerning hip pain 1, 2
  • Standard protocol: AP view of pelvis, dedicated AP view of symptomatic hip, and cross-table lateral view 2
  • Include pelvis in views to allow comparison with contralateral side 2

Advanced Imaging for Persistent Concerns

• MRI without contrast (sensitivity 99-100%) is recommended when:

  • Radiographs are negative but clinical suspicion for fracture remains high
  • Infection or tumor is suspected
  • Osteonecrosis is a concern 1, 2

• CT scan may be used when MRI is contraindicated, though it has lower sensitivity (79-94%) for occult fractures 2

Diagnostic Algorithm for Red Flags

1. Initial Assessment: Evaluate for inability to bear weight, fever, trauma history, night pain, weight loss
2. Physical Examination: Check for deformity, range of motion, neurovascular status, fever
3. Immediate Radiographs: AP pelvis and lateral hip views
4. If Radiographs Negative but Red Flags Present: Proceed to MRI without contrast
5. If Infection Suspected: Consider joint aspiration under ultrasound guidance 1

Clinical Implications of Delayed Diagnosis

Relying solely on negative radiographs when clinical suspicion remains high can lead to:

• Increased complications
• Extended hospital stays
• Higher mortality rates
• Risk of osteonecrosis 2

Early detection of serious conditions like occult fractures, infections, or tumors is critical for preventing permanent disability or life-threatening complications 1, 2.

Key Point

When evaluating hip pain, always maintain a high index of suspicion for serious pathology, especially when red flags are present, as timely diagnosis and intervention can significantly impact patient outcomes.

KMK: Hip pain red flags