Obtain Plain Radiographs of the Hip Immediately
The next step is to obtain plain radiography of the right hip, including an anteroposterior (AP) view with 15 degrees of internal rotation and a cross-table lateral view. This is the initial imaging modality of choice for acute traumatic hip pain 1.
Clinical Reasoning
The presentation of pain with internal rotation and inability to bear weight strongly suggests an acute hip fracture or dislocation, which requires urgent diagnosis to reduce morbidity and mortality. Hip fractures cannot be definitively diagnosed or excluded by physical examination alone 1.
Why Radiographs First?
- Rapid diagnosis reduces morbidity: Delays in diagnosis increase complication rates, hospital length-of-stay, costs, and mortality 1
- Surgical delay >12 hours significantly increases 30-day mortality risk in hip fracture patients 1
- Radiographs are fast, portable, and can be performed without moving the patient, minimizing risk of fracture displacement 1
- The cross-table lateral view is specifically favored over frog-leg lateral due to potential risk of fracture displacement with the frog-leg technique 1
Standard Views Required
- AP view with 15 degrees of internal rotation
- Cross-table lateral view of the affected hip
- Many institutions also include an AP pelvis view for hip symmetry assessment 1
If Radiographs Are Negative or Indeterminate
If clinical suspicion remains high despite negative radiographs, proceed immediately to cross-sectional imaging (CT or MRI) to detect radiographically occult fractures 1. Multiple studies demonstrate the critical importance of advanced imaging in revealing occult hip fractures in patients with acute traumatic hip pain 1.
Key Clinical Pitfall
Do not delay imaging based on physical examination findings alone. The classic presentation of external rotation, abduction, and leg shortening occurs with displaced fractures 2, but non-displaced or occult fractures may have pain out of proportion to physical findings yet still require urgent surgical intervention 3.
Additional Considerations
While visceral processes (such as perirectal abscess) can rarely cause referred hip pain and inability to ambulate 3, the presentation of pain with internal rotation and inability to bear weight in the context of acute onset makes fracture or dislocation the primary concern requiring immediate exclusion through imaging.