Stress radiography for clinical evaluation of anterior shoulder instability

The purpose of this study was to examine the validity of stress radiography using the Telos GA-IIE as a clinical methodology to evaluate shoulder instability.

On 36 anterior shoulder dislocators and 23 uninjured volunteers, 4 types of stress radiographs were captured while applying 15 daN of force anteriorly (AER0 and AER60) and posteriorly (PER0 and PER60) at 2 different positions: (1) 90° of abduction combined with 0° external rotation and (2) 90° of abduction combined with 60° external rotation. The results of the anterior drawer test and of the same test under anesthesia were correlated.

AER0 and AER60 from the affected shoulder revealed significantly larger displacement than on the normal side (P < .05), and all 4 radiographs from the affected joints demonstrated significantly larger displacement (P < .05) than in the volunteers. Among the 4 types of radiographs, AER0 and AER60 showed significantly higher displacement in the patients (P < .001), whereas there were no differences in the volunteers (P = .167). The results of the anterior drawer test positively correlated to AER60 (Pearson correlation coefficient [PCC] = 0.453; P = .005) and AER0 (PCC = 0.529; P = .001), and those of examination under anesthesia weakly correlated to AER60 (PCC = 0.287; P = .264) but highly correlated to AER0 (PCC = 0.695; P = .002).

Stress radiographs on the affected shoulder frequently correlated with physical examinations, and the displacement of >3 mm on AER0 suggests anterior instability.