Investigation of hip injury (summary)
Citation, DOI & article data
This is a basic article for medical students and other non-radiologists
Hip injury is an important, but relatively uncommon reason to present to emergency services. As with other traumatic presentations, age distribution is bimodal with high-energy trauma in the younger population and potentially trivial mechanisms of injury in the older population, e.g. a simple fall.
Assessment involves a thorough history and examination. Assessment of the leg at rest may demonstrate it to be shortened and internally rotated - features of a neck of femur fracture.
In the elderly it is also worth considering whether a fall was the result of a simple trip, or secondary to another reason, e.g. seizure, cardiovascular trigger, stroke or loss of consciousness. Relevant assessment of the cardiovascular or neurological system may be required with additional tests, e.g. ECG, CT brain.
The first investigation of choice in a patient with hip pain following trauma is a hip x-ray. This will be an AP radiograph of the pelvis and a lateral radiograph of the painful hip.
Fractures are not always identified on initial x-ray imaging. If there is a clinical concern for a hip fracture, but the x-ray is normal, further imaging is required. Both CT and MRI can be used to look for a radiographically occult fracture - MRI is more sensitive, but CT is usually easier to organize and in many institutions is the second-line investigation of choice.
In complex fractures, CT can be helpful to get additional preoperative information that can be used to plan surgery and aid discussion about consent and prognosis.
It is also worthwhile considering that interpretation of a hip x-ray will be complicated in the elderly by the present of other conditions, e.g. secondary osteoarthritis.