Three dimensional scapular prints for evaluating glenoid morphology: An exploratory study

Computerised Tomography (CT) scans are conventionally employed to assess the glenoid morphology prior to total shoulder arthroplasty (TSA). This study explores the role of three-dimensional (3D) models for assessing glenoid morphology.

CT scans of 32 patients scheduled for TSA were reconstructed to scapular models using customised software and a desktop 3D printer. The size and aspect ratios were maintained. Glenoid version, glenoid maximum height and width, and the maximum acromion antero-posterior (AP) length were compared between the models and CT scans.

The models were an accurate qualitative reflection of scapular anatomy. The average retroversion in 3D models was 8.19°±30.8° compared to 10.26°±42.5° in scan images. The mean difference was 2.07°±24.6° (p=0.408). However, the mean absolute error was 5.02°±12.3°. The mean difference of the glenoid maximum width and the acromion maximum AP length was 0.22±3.33mm (p=0.862) and 0.32±14.12mm (p=0.213) respectively. However, the mean difference was significant for the glenoid maximum height measuring 3.67±12.04mm with p=0.004. The correlation between the examiners was high for all parameters, with intraclass correlation ranging between 0.94 and 0.99.

3D printing technology promises to be a useful tool for preoperative planning with accurate reproduction of transverse plane anatomy. 3D prints represent superior definition of reconstructed anatomical measures such as glenoid height as compared to conventional CT Scans.