From the Guidelines
For patients with suspected occult hip fractures and negative radiographs, MRI of the pelvis and affected hip is the recommended next imaging study due to its high sensitivity and ability to characterize fracture morphology. This recommendation is based on the high diagnostic accuracy of noncontrast MRI for detecting radiographically occult proximal femoral fractures, with studies showing near 100% sensitivity 1. The use of MRI allows for early diagnosis and appropriate treatment, reducing the risk of complications such as displacement, avascular necrosis, and poorer outcomes.
Key Points to Consider
- MRI is the gold standard for detecting occult hip fractures due to its high sensitivity and specificity 1
- Noncontrast MRI is sufficient for fracture detection, with no need for IV gadolinium contrast solely for this purpose 1
- Specific scanning protocols, such as coronal short tau inversion-recovery (STIR) sequence, can provide high sensitivity and specificity for fracture detection 1
- CT scans may be used in emergency settings due to faster acquisition time and greater availability, but MRI remains the preferred choice due to its higher sensitivity and ability to characterize fracture morphology 1
Clinical Implications
- Early diagnosis and treatment of occult hip fractures are crucial to prevent complications and improve outcomes 1
- MRI should be considered the next imaging study after negative radiographs in patients with suspected occult hip fractures 1
- Treatment depends on fracture location and pattern, but typically involves surgical fixation for most displaced fractures and some non-displaced fractures to prevent complications and allow earlier mobilization 1
From the Research
Occult Hip Fracture Diagnosis using CT
- CT scans can be used as an initial diagnostic tool for occult hip fractures, with a detection rate comparable to MRI in some studies 2, 3.
- A proposed diagnostic protocol involves initial CT scanning, followed by MRI only if the CT scan is negative for fracture, which can be a practical and cost-effective solution 4.
- The use of CT as a first-line investigation can reduce time to diagnosis and lower overall costs, with an estimated cost savings of 66,805 Euro during a four-year study period 4.
Comparison of CT and MRI for Occult Hip Fractures
- MRI has traditionally been considered a superior modality for detecting occult hip fractures, but modern multislice CT may be comparable in terms of detection rate 2, 3.
- A retrospective review of 179 patients found that CT and MRI had similar detection rates for occult hip fractures, with no patients re-presenting with unidentified fractures or other localized hip pathology within a 12-month period 3.
- However, another study found that MRI was more accurate than CT scan for obtaining early diagnosis of occult hip fractures, with four out of six CT images resulting in misdiagnosis due to inaccuracy 5.
Clinical Guidelines and Recommendations
- Current guidelines state that patients should be offered MRI if hip fracture is suspected despite negative hip radiographs, but CT may be a valid first-line investigation for suspected plain X-ray occult hip fracture 6.
- A high index of suspicion and early imaging referral for elderly patients presenting with non-specific hip pain following a fall is recommended, with CT or MRI as the initial diagnostic tool 3, 6.