Imaging Work‑up for Hip Pain

Initial Imaging Recommendation

Obtain an anteroposterior (AP) pelvis radiograph and a lateral femoral head‑neck view (Dunn, frog‑leg/Lauenstein, or cross‑table) as the first imaging study for every patient presenting with hip pain, because these plain films give essential information on bony morphology and can identify fractures, dislocations, and structural abnormalities. 1, 2

Perform the FADIR (flexion‑adduction‑internal rotation) test; a negative result helps rule out intra‑articular hip disease in young and middle‑aged active adults. 2, 3
Actively screen for extra‑hip sources of pain—including lumbar spine pathology, intra‑abdominal/pelvic conditions, and other musculoskeletal disorders—and exclude them before attributing symptoms to the hip. 4
Never base a diagnosis solely on imaging findings; imaging must be interpreted together with the patient’s history and physical‑exam results. 2, 5, 6

The AP pelvis view is a core component of the initial radiographic series for hip evaluation. 1, 2
The lateral femoral head‑neck view complements the AP view and is essential for assessing bony morphology. 2, 7

Use non‑contrast computed tomography (CT) as the first advanced imaging modality when a fracture is suspected but plain films are negative or indeterminate. 1
If CT remains negative or equivocal and clinical suspicion persists, proceed to non‑contrast magnetic resonance imaging (MRI). 1

MRI without contrast is the preferred next‑step imaging after negative or indeterminate radiographs for evaluating soft‑tissue injuries. 1
MRI detects 100 % of proximal hamstring avulsions, compared with only 58.3 % detection by ultrasound, demonstrating its superior diagnostic performance. 1
Ultrasound lacks sufficient evidence for acute tendon, muscle, or ligament assessment and should not be used as the subsequent imaging study. 1

Employ MRI or magnetic resonance arthrography (MRA), or CT arthrography, when detailed assessment of the labrum, cartilage, or ligamentum teres is required. 2, 3, 7
Choose three‑dimensional imaging techniques when a morphological evaluation of intra‑articular structures is indicated. 2, 8
Recognize that labral, chondral, and ligamentum teres abnormalities are frequently present in asymptomatic individuals; therefore, imaging findings must be correlated with clinical presentation. 3, 4

Repeat AP and lateral radiographs after reduction to confirm successful relocation of the hip joint. 1
Obtain non‑contrast CT if a large posterior acetabular wall fracture is suspected or if reduction difficulty is encountered. 1

Use non‑contrast CT to further characterize fracture alignment for surgical planning. 1
Consider non‑contrast MRI to identify incomplete intertrochanteric fracture extension when needed. 1

Femoroacetabular impingement (FAI) syndrome – identified by combined clinical and imaging criteria. 5
Acetabular dysplasia and/or hip instability – diagnosed based on radiographic morphology and clinical instability signs. 3
Other conditions – include soft‑tissue pathologies such as labral tears, cartilage lesions, or ligamentum teres injuries without specific bony deformities. 3

Do not rely on ultrasound for acute tendon or muscle injuries; MRI provides markedly higher detection rates for hamstring avulsions (100 % vs 58.3 %). 1
Do not over‑interpret incidental intra‑articular findings, as many such abnormalities are present in asymptomatic people. 3, 4, 7
Do not skip plain radiographs; they remain the essential first imaging step regardless of the suspected underlying pathology. 1, 2
Do not make a definitive diagnosis based solely on positive imaging; imaging typically shifts post‑test probability only modestly (small to moderate effect). 5, 6, 8