Reliability of Radiographs and Computed Tomography in Diagnosing Scaphoid Union After Internal Fixation.

PURPOSE:
To evaluate the reliability of radiographs (XR) alone versus the combination of XR and computed tomography (CT) in determining scaphoid union following open reduction internal fixation (ORIF) with a headless compression screw.

METHODS:
We used our imaging database to identify 32 XR and corresponding CTs over a 6-year period (from 2012 to 2018) that were performed to evaluate scaphoid healing following ORIF. Three hand surgeons evaluated the studies to assess (1) healing, (2) if partially healed, the percentage of healing, and (3) the certainty of healing. Initially, XR were reviewed alone. Three weeks later, the same XR were reviewed with the corresponding CTs. Each reviewer performed a similar 2-stage evaluation 4 weeks later. We measured interobserver and intraobserver reliabilities using linearly weighted kappa (κ) coefficients for healing status and the percentage of healing.

RESULTS:
The interobserver reliability for healing (healed vs partially healed vs not healed) was moderate both with XR alone and with the combination of XR and CT. The intraobserver reliability for healing was substantial with XR alone compared to moderate with the combination of XR and CT. For the percentage of healing, both interobserver and intraobserver reliabilities were fair with XR alone or with the combination of XR and CT. Reviewers reported significantly greater certainty with the combination of XR and CT compared with XR alone.

CONCLUSIONS:
Following ORIF, surgeons are more certain in their evaluation of scaphoid healing with the combination of CT and XR. However, the reliability of assessing scaphoid union may not be improved by the addition of CT to XR.

TYPE OF STUDY/LEVEL OF EVIDENCE:
Diagnostic III.