X-Ray Views for Left Hip Pain After Severe Injury
For a patient with left hip pain six days after severe injury, order an AP pelvis radiograph with 15 degrees of internal hip rotation and a cross-table lateral view of the affected left hip. 1
Initial Imaging Approach
The ACR Appropriateness Criteria (2024 update) establishes radiography as the initial imaging modality of choice for acute traumatic hip pain 1. This approach prioritizes rapid diagnosis to reduce morbidity associated with delayed fracture detection and potential osteonecrosis.
Standard Views Required:
- Anteroposterior (AP) view with 15 degrees of internal hip rotation
- Cross-table lateral view of the affected hip
- AP pelvis view for hip symmetry assessment and detection of associated pelvic fractures 1
Rationale for These Specific Views
Why cross-table lateral instead of frog-leg lateral? The cross-table lateral is strongly preferred because the frog-leg technique carries risk of fracture displacement in patients with occult fractures 1. This is a critical safety consideration six days post-injury when an occult fracture may have progressed.
Why include AP pelvis? Patients with proximal femur fractures frequently have concomitant pelvic fractures (sacrum, pubic rami) that may occur in isolation or alongside hip fractures 2. The pelvis view also allows comparison to the contralateral side 2.
Important Clinical Caveat
Negative radiographs do NOT exclude fracture. Approximately 10% of proximal femoral fractures are radiographically occult 2. Given that this patient has persistent pain six days after injury, you must maintain high suspicion for occult fracture even if initial radiographs appear normal.
Next Steps if Radiographs Are Negative
If radiographs are negative but clinical suspicion remains high (persistent pain, inability to bear weight), immediately proceed to MRI without IV contrast of the pelvis and affected hip 1. MRI demonstrates 99-100% sensitivity for occult hip fractures and can also detect:
- Iliacus hematoma (relevant to your clinical concern) 3
- Soft tissue injuries
- Pelvic fractures not visible on radiographs 2
Alternative if MRI unavailable: CT hip without IV contrast can be obtained more rapidly than MRI and is useful for detecting radiographically occult fractures, though it is less sensitive than MRI 1. CT is particularly valuable when rapid diagnosis is essential and MRI access is delayed.
Addressing Iliacus Hematoma Concern
For suspected iliacus hematoma specifically, MRI is superior to radiographs as it directly visualizes the hematoma and can assess for femoral nerve compression 4, 3. However, start with radiographs first to rule out fracture, then proceed to MRI if radiographs are negative or if neurologic symptoms (femoral nerve paralysis, quadriceps weakness) are present 3.
Timing Considerations
Six days post-injury represents a critical window where delayed diagnosis significantly increases morbidity. Rapid imaging reduces length of immobility and risk of osteonecrosis 1. Do not delay imaging while awaiting symptom resolution—persistent pain at this timepoint mandates definitive imaging evaluation.