Scaphoid Injury Workup

Updated: Sep 11, 2019
  • Author: Scott R Laker, MD; Chief Editor: Stephen Kishner, MD, MHA  more...
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Workup

Laboratory Studies

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  • No laboratory studies are indicated for the diagnosis of scaphoid fracture.

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Imaging Studies

Radiographic examination

Plain radiographs are limited in their ability to detect fractures within 2-6 weeks of the injury. When a scaphoid fracture is suggested on physical examination, a scaphoid series (including a posteroanterior [PA] view with the wrist in ulnar deviation) should be ordered, because routine wrist anteroposterior (AP), lateral, and oblique views may not show the fracture. Based on retrospective studies and cadaveric review, the most sensitive radiographic evaluation includes four views: PA, lateral, pronated oblique (60° pronated oblique), and ulnar deviated oblique (also described as 60° supinated oblique). [2, 3]

Comparison views of the contralateral wrist may be necessary. Importantly, as many as 25% of scaphoid fractures are not evident on initial radiographs, and the radiographs may not definitively delineate fracture alignment, in which case magnetic resonance imaging (MRI) or computed tomography (CT) scanning is warranted. Immobilization in a thumb spica splint or cast for 7-14 days is recommended prior to repeat imaging.

If the radiographs are equivocal and it is important for an athlete to return to competition without waiting 7-14 days for repeated radiographs, a bone scan may be obtained after 72 hours. [4]

A study by Hannemann et al indicated that in terms of revealing the union of nondisplaced scaphoid waist fractures after 6 weeks of cast immobilization, conventional radiography has an average sensitivity and specificity of 65% and 67%, respectively, as well as positive and negative predictive values of 93% and 22%, respectively. [11]

For radiographically negative studies: MRI, CT, or bone scan 

For patients with radiographically negative studies, there is no consensus on the next best diagnostic test. ​If a diagnosis cannot be confirmed with confidence on routine films, a technetium-99m (99mTc) bone scan or an MRI scan of the wrist is recommended. [4, 5]  Bone scanning has a sensitivity of 99% but a specificity of 86% and so would result in overtreatment of 112/1000 patients. MRI has a sensitivity of 88% and a specificity of 100%, missing fractures in 24/1000 patients but resulting in no overtreatment (although MRI sensitivity and specificity have been reported to be as high as 100% and 96.3%, respectively, in the acute setting of suspected scaphoid fracture. [12] ). MRI has the added benefit of highlighting soft tissue structures, and timing does not affect accuracy. CT scanning has a sensitivity of 72% and a specificity of 99%, missing fractures in 56/1000 patients and resulting in overtreatment in 8/1000 patients; similar to MRI, timing does not affect its accuracy. [13]

MRI

MRI is often used because it offers several distinct advantages; specifically, the modality is noninvasive and readily available, and it can assess bone healing and evaluate for bone contusions and ligamentous injuries. [14, 15]

Tibrewal et al concluded that MRI is the most effective imaging tool for diagnosing a clinically suspected scaphoid fracture. [16, 17]

A British study looked into the cost effectiveness of MRI and found that the direct cost of the modality did not significantly increase health care costs; additionally, when accounting for productivity losses incurred by unnecessary casting, MRI was found to be much more cost effective. [18]  Several articles suggest that MRI is a very reasonable next step in cases in which fracture is highly suspected despite initial negative radiographic findings.

A prospective, noncontrolled study by Bervian et al indicated that in cases of scaphoid fracture nonunion, the presence of marked low signal intensity on T1-weighted MRI scans and the absence intraoperatively of punctate bone bleeding strongly suggest osteonecrosis of the proximal fragment. [19]

CT scanning

Computed tomography (CT) scanning has very good interobserver and intraobserver reliability, although fractures with less than 1 mm of displacement are often not detected. [20]  Its sensitivity and specificity are estimated to be 100% when used 5-10 days postinjury. Bone scan sensitivity was noted to be 78% in this study.

Bone scanning

One prospective study found that bone scans performed 3-7 days postinjury are 92% sensitive and 87% specific. Another prospective study found minimal interobserver and intraobserver variability. [20]

One systematic review suggested that a negative bone scan virtually excludes fracture, with a negative likelihood ratio of 0.12. [9]

Other imaging modalities

High-resolution ultrasonography is also being investigated for the diagnosis of scaphoid fracture, but it relies heavily on the technical skill of the examiner. [15]

Intrasound vibration examination also has been used to detect the occult, undiagnosed scaphoid fracture. [21]

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