The acromion in supraspinatus outlet and Rockwood caudal tilt views from three-dimensional computed tomography scan of the shoulder.

BACKGROUND

A hooked acromion on an outlet view and a keeled acromion on Rockwood tilt radiographs are associated with rotator cuff tears. The identification of the acromial morphology may be helpful for acromioplasty planning with regarding the acromial types.

METHODS

Descriptive Laboratory Study. Three-dimensional computed tomography scans models of 108 shoulders in 91 patients with; (1) Normal shoulders, (2) Shoulders with osteoarthritis, and (3) Irreparable rotator cuff tears; were created and adjusted manually to provide the proper supraspinatus outlet and Rockwood views. The acromial morphology/spurs were analyzed, classified and tested for reliability.

RESULTS

The intra-observer reliability of supraspinatus outlet view had a weak-to-strong agreement [0.828 (95%CI: 0.716-0.945, p-value<0.001), and 0.475 (95%CI: 0.288-0.672, p-value<0.001 from 2 evaluators]. The inter-rater of the supraspinatus outlet view has a minimal-to-moderate agreement [0.782 (95%CI: 0.662-0.907, p-value<0.001), and 0.344 (95%CI: 0.157-0.539, p-value<0.001) in the first and second readings]. The intra-observer reliability of the Rockwood view has a moderate-to-almost-perfect agreement [0.752 (95%CI: 0.652-0.860, p-value<0.001), and 0.903 (95%CI: 0.833-0.974, p-value<0.001) from 2 evaluators]. The inter-observer reliability of the Rockwood view has a moderate-to-strong agreement [0.854 (95%CI: 0.777-0.936, p-value<0.001), and 0.737 (95%CI: 0.634-0.847, p-value<0.001) in the first and second readings].

CONCLUSION

The classification of acromion morphology under Three-dimensional computed tomography in the supraspinatus outlet view has poor reliability. The Rockwood caudal tilt view model results in moderate-to-almost-perfect reliability that can be developed to the plain radiographic classification to determine the need for acromioplasty in rotator cuff surgery.