Follow-up radiographs are usually used as the
reference standard for the diagnosis of suspected scaphoid fractures. However,
these are prone to errors in interpretation. We performed a meta-analysis
of 30 clinical studies on the diagnosis of suspected scaphoid fractures,
in which agreement data between any of follow-up radiographs, bone scintigraphy,
magnetic resonance (MR) imaging, or CT could be obtained, and combined
this with latent class analysis to infer the accuracy of these tests
on the diagnosis of suspected scaphoid fractures in the absence
of an established standard. The estimated sensitivity and specificity
were respectively 91.1% and 99.8% for follow-up radiographs, 97.8%
and 93.5% for bone scintigraphy, 97.7% and 99.8% for MRI, and 85.2%
and 99.5% for CT. The results were generally robust in multiple
sensitivity analyses. There was large between-study heterogeneity
for the sensitivity of follow-up radiographs and CT, and imprecision
about their sensitivity estimates. If we acknowledge the lack of a reference standard for diagnosing
suspected scaphoid fractures, MRI is the most accurate test; follow-up
radiographs and CT may be less sensitive, and bone scintigraphy
less specific.
This study identified variables which influence the outcome of surgical management on 126 ununited scaphoid fractures managed by internal fixation and non-vascular bone grafting. The site of fracture was defined by a new method: the ratio of the length of the proximal fragment to the sum of the lengths of both fragments, calculated using specific views in the plain radiographs. Bone healing occurred in 71% (89) of cases. Only the site of nonunion (p = 1 × 10−6) and the delay to surgery (p = 0.001) remained significant on multivariate analysis. The effect of surgical delay on the probability of union increased as the fracture site moved proximally. A prediction model was produced by stepwise logistic regression analysis, enabling the surgeon to predict the success of surgery where the site of the nonunion and delay to surgery is known.
