Is conventional radiography still relevant for evaluating the acromioclavicular joint?

Introduction Conventional radiography using an anteroposterior view of the acromioclavicular (AC) joint is the gold standard for evaluating arthritic degeneration. Objective Based on a standardised AP view of the AC joint, the objective of this study was to determine whether this radiographic view is reliable and reproducible for evaluating the AC joint space. Methods A cadaver scapulaclavicle unit, free of osteoarthritis, was used for this study. The scapula was positioned in a stand; and then with fluoroscopy guidance, a strict AP view of the AC joint was taken. Starting from this 0 position, a radiograph was taken by varying the angle by 5 degrees, 10 degrees, and 15 degrees in every plane in space. All radiographs were taken during a single session to ensure the distance between the X-ray tube and scapula did not change. The images were then exported to OsiriX for processing; the superior and inferior AC distance and the joint area were measured. Results There was no reproducibility in the AC joint measurements as a function of the incidence angle relative to a strict AP view. Conclusion Conventional radiography using an AP view of the AC joint cannot be used to do a fine analysis of arthritic degeneration of this joint. It is likely that only CT scan or MRI is sufficient to analyse osteoarthritis in this joint. Level of evidence IV, basic science study. (C) 2020 Elsevier Masson SAS. All rights reserved.