Order an X-ray, Not a CT
You should order a plain radiograph (X-ray) of the hip, not a CT scan, as the initial imaging study for this patient with hip pain. 1, 2
Why X-ray is the Correct Initial Choice
- Plain radiography is the initial imaging modality of choice for evaluating hip pain in adults, regardless of whether the pain is acute traumatic or chronic in nature 1, 2
- The American College of Radiology explicitly states that there is no evidence to support the use of CT without IV contrast as the initial imaging study for hip pain evaluation 1
- Radiographs serve as an excellent screening tool that can identify common disorders such as osteoarthritis, fractures, dysplasia, femoroacetabular impingement, and bone tumors 2, 3
Standard X-ray Views to Order
- Request an anteroposterior (AP) view of the pelvis with 15 degrees of internal hip rotation and a frog-leg lateral view of the symptomatic hip 2, 3, 4
- Many institutions include an AP view of the pelvis for assessment of hip symmetry, which provides valuable comparative information 1
What Happens After the X-ray
If X-rays Show Pathology
- Plain radiographs may provide definitive diagnosis for conditions like osteoarthritis, fractures, or bone lesions, allowing you to proceed directly with treatment 2, 5
If X-rays Are Negative, Equivocal, or Nondiagnostic
- MRI of the hip without IV contrast is the next appropriate imaging study, rated 9/9 (usually appropriate) by the American College of Radiology 2, 6, 7
- MRI is highly sensitive and specific for detecting soft tissue abnormalities (tendonitis, bursitis, muscle/tendon tears), occult fractures, labral tears, and bone marrow edema patterns 2, 6, 8
- Ultrasound can be used as an alternative for evaluating specific soft tissue structures like trochanteric bursitis or iliopsoas tendinopathy 2, 7
Why CT is Inappropriate Here
- CT is primarily reserved for acute trauma settings, particularly for evaluating acetabular fractures, hip dislocations, intra-articular fragments, and surgical planning 9, 10
- CT provides poor soft tissue evaluation compared to MRI and exposes the patient to unnecessary radiation without diagnostic benefit for chronic hip pain 7, 8
- In a comparative study, CT resulted in misdiagnosis in 4 out of 6 patients with occult hip fractures, while MRI was accurate in all cases 8
Critical Pitfalls to Avoid
- Never skip plain radiographs and proceed directly to advanced imaging like CT or MRI—this violates established imaging algorithms and wastes healthcare resources 1, 2
- In elderly patients with osteopenia (common in this age group), if radiographs are negative but clinical suspicion for fracture remains high, order MRI urgently rather than CT, as up to 10% of hip fractures are radiographically occult initially 6, 8
- Don't assume that the ability to ambulate excludes fracture—many occult hip fractures allow limited weight-bearing initially 6