Twenty-six studies (total number of participants unclear) were included in the review; some studies assessed more than one imaging modality. Most studies had some methodological limitations; only two studies satisfied all criteria. Most studies (>70%) met criteria for adequate patient spectrum, avoidance of partial verification, independent reference test, adequate description of index test, blind assessment of index test, availability of clinical data and handling of uninterpretable results and withdrawals. Few studies (≤35%) met criteria for adequate description of reference standard and blind interpretation of reference standard. The prevalence of scaphoid fracture in included studies ranged from 5% to 50%.
Fifteen studies of bone scintigraphy (1,102 participants) gave a pooled estimate for sensitivity of 97% (95% CI 93% to 99%), a pooled estimate for specificity of 89% (95% CI 83% to 94%) and a pooled estimate for lnDOR of 4.78 (95% CI 4.02 to 5.54). There was significant statistical heterogeneity in estimates of sensitivity (I2=85%).
Ten studies of MRI (513 participants) gave a pooled estimate for sensitivity of 96% (95% CI 91% to 99%), a pooled estimate for specificity of 99% (95% CI 96% to 100%) and a pooled estimate for lnDOR of 6.60 (95% CI 5.43 to 7.76).
Six studies of CT (211 participants) gave a pooled estimate for sensitivity of 93% (95% CI 83% to 98%), a pooled estimate for specificity of 99% (95% CI 96% to 100%) and a pooled estimate for lnDOR of 6.11 (95% CI 4.56 to 7.66).
Two studies reported data for ultrasound (n=72), with sensitivity estimates of 100% (95% CI 48% to 100%) and 78% (95% CI 40% to 97%) and specificity estimates of 98% (95% CI 89% to 100%) and 89% (95% CI 52% to 100%).
Comparative SROC analyses showed that MRI had a higher diagnostic performance than bone scintigraphy (relative DOR 4.85, 95% CI 1.42 to 16.52) and a similar diagnostic performance to CT; there was no significant difference in performance between CT and bone scintigraphy. Meta-regression analyses indicated that longer time periods between injury and imaging were associated with increased specificity for bone scintigraphy; no other variables were significant. Sensitivity analyses did not significantly change results.
Likelihood ratios were reported.