Should arthro-CT be used routinely to assess glenoid bone defects in anterior glenohumeral instability?

In cases of chronic anterior shoulder instability, surgical indications are guided by clinical and morphological parameters that are largely integrated into the ISIS score. The glenoid bone defect is a central decision factor. Arthro-CT represents for many the frequently used examination, but is this superiority proven for the evaluation of glenoid lesions and is its systematic use justified?

Our aim was to compare the Bernageau view versus arthro-CT for the assessment of glenoid bone defects in anterior glenohumeral instability, and to integrate our results into the diagnostic approach.

We report a retrospective study of 95 patients with chronic anterior shoulder instability, mean age 28.7 ± 11.6 years. A sample of 23 patients was selected who underwent arthro-CT of the pathological shoulder and bilateral Bernageau views. The bone defect on the Bernageau view is expressed as a percentage of the width of the healthy glenoid; on the arthro-CT it was assessed using the Sugaya method. Associated lesions (Bankart, notches, SLAP, HAGL and rotator cuff tear) were collected on the various examinations. The measurement method on the two images was validated by two examiners with high inter- and intra-observer reproducibility (ICC between 0.84 and 1). Statistical evaluation was based on non-parametric tests.

The glenoid defect calculated on the Bernageau view was 5.90% (±7.56) compared with 5.93% (±6.59) for arthro-CT, the mean difference between the two measurements was 1.92 (±1.86). There were no statistically significant differences based on the Wilcoxon test (p = 0.85, CI95% [0.577; 0.911]). The Spearmann correlation coefficient between the two methods was 0.8 (CI 95% [0.577; 0.911], p < 0.001). Associated lesions included: 44% glenoid fracture, 81% Bankart lesion, 8.3% HAGL, 73% Hill-Sachs lesions, 5% SLAP and 2.1% rotator cuff tears.

Our study supports the finding that bilateral Bernageau views provide accuracy comparable to arthro-CT in quantifying glenoid defects. Arthro-CT, which is more invasive, requires more radiation and is a potential source of infectious complications, provides additional information that is only relevant in the case of SLAP and rotator cuff tears. We therefore recommend reserving arthro-CT for the pre-therapeutic assessment of instability in specific cases: Bankart indication, patients ≥ 40 years old, or symptomatic patients of any age (functional deficits, muscle weakness, or pain during rotator cuff testing).

IV.