Femoral Neck Fracture Workup

Updated: Jan 19, 2016
  • Author: Gerard A Malanga, MD; Chief Editor: Sherwin SW Ho, MD  more...
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Workup

Laboratory Studies

See the list below:

  • Laboratory studies generally are not necessary for the diagnosis of femoral neck fractures.

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Imaging Studies

See the list below:

  • Plain radiographs

    • Plain radiographs have traditionally been ordered as the initial step in the workup of hip fractures. The main purpose of x-ray films is to rule out any obvious fractures and to determine the site and extent of the fracture. Plain radiographs have poor sensitivity. The presence of periosteal bone formation, sclerosis, callus, or a fracture line may indicate a stress fracture; however, a plain radiograph may appear normal in a patient with a femoral neck stress fracture, and radiographic changes may never appear.

    • Radiographs may show a fracture line on the superior aspect of the femoral neck, which is the location for tension fractures. Tension fractures must be distinguished from compression fractures, which, according to Devas [13] and Fullerton and Snowdy, [14] are usually located on the inferior aspect of the femoral neck.

    • The standard radiographic examination of the hip includes an anteroposterior view of the hip and pelvis and a cross-table lateral view. The frog-leg lateral view is poorly tolerated and may result in fracture displacement. If a femoral neck fracture is suggested, an internal rotation view of the hip may be helpful to identify nondisplaced or impacted fractures. If a hip fracture is suggested but not seen on standard x-ray films, a bone scan or magnetic resonance imaging (MRI) study should be performed.

  • Bone scanning

    • Bone scans can be helpful when a stress fracture, tumor, or infection is suggested. Bone scans are the most sensitive indicator of bone stress, but they have poor specificity. Shin et al reported that bone scans have a 68% positive predictive value. [16] Bone scans are limited by relatively poor spatial resolution of the pertinent anatomy of the hip.

    • In the past, a bone scan was thought to be unreliable before 48-72 hours after a fracture; however, a study by Holder et al found a sensitivity of 93%, regardless of the time from injury. [17]

  • MRI

    • MRI has been shown to be accurate in the assessment of occult fractures and can be reliably performed within 24 hours of the injury; however, these studies are expensive.

    • With MRI, a stress fracture typically appears as a fracture line at the cortex surrounded by an intense zone of edema in the medullary cavity.

    • In a study by Quinn and McCarthy, T1-weighted MRI findings were found to be 100% sensitive in patients with equivocal radiographic findings. [18] Shin et al showed that MRI findings are 100% sensitive, specific, and accurate in identifying a femoral neck fracture. [16]

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