Intercarpal Angles on Hand Versus Wrist Films: Are Hand Radiographs Sufficient for Assessing Intercarpal Angles?

Purpose

Carpal angles traditionally are measured on the lateral projection of a standard wrist series; however, this often necessitates obtaining additional radiographic views resulting in additional radiation exposure and increased cost. We aimed to determine whether carpal angles could be measured accurately on a standard series of hand radiographs when compared to wrist radiographs.

Methods

Carpal indices were measured on lateral wrist and hand radiographs of 40 patients by three orthopedic upper extremity surgeons. Inclusion criteria were no metabolic disease, no hardware, no fractures, radiographic positioning of the wrist in flexion/extension <20°, minimum 3 cm of distal radius visible, and acceptable scaphopisocapitate relationship (defined as the volar cortex of the pisiform lying between the volar cortices of the distal pole of the scaphoid and capitate). Angles measured included radioscaphoid (RSA), radiolunate (RLA), scapholunate (SLA), capitolunate (CLA), and radiocapitate (RCA). Measurements on wrist versus hand radiographs were compared for each patient. Interclass correlation coefficients (ICCs) were computed to assess interrater and intrarater agreement.

Results

Interrater agreement for hand and wrist radiographs were (respectively): SLA 0.746 and 0.763, RLA 0.918 and 0.933, RCA 0.738 and 0.538, CLA 0.825 and 0.650, RSA 0.778 and 0.829. Interrater agreement was superior in favor of hand radiographs for the RCA (0.738 [0.605–0.840] vs 0.538 [0.358–0.700]) and CLA (0.825 [0.728–0.896] vs 0.650 [0.492–0.781]), but not the SLA, RLA, or RSA. Two of the three raters had excellent intrarater agreement for all hand radiograph measures (ICC range, 0.907–0.995). The mean difference in measured angles on hand versus wrist radiographs was <5° for all angles.

Conclusions

Carpal angles may be measured reliably on hand radiographs with an acceptable scaphopisocapitate relationship and wrist flexion/extension of <20°.

Clinical relevance

By mitigating the need to obtain additional radiographic views, surgeons may be able to reduce the cost and radiation exposure to their patients.