The interobserver reliability in diagnosing osseous lesions after first-time anterior shoulder dislocation comparing plain radiographs with computed tomography scans.

BACKGROUND

Recurrence after first-time traumatic anterior shoulder dislocation is frequent. The prevalence of glenoid bone loss ranges from 41% after a first-time dislocation to 86% with recurrent dislocation. Postoperative recurrence can occur in up to 10% of cases. Thus, misdiagnosis of bony glenoid rim lesions has been assumed a major cause for failure. We evaluated the interobserver reliability of radiologic diagnoses after first-time traumatic shoulder dislocation based on radiographs and computed tomography (CT) images.

METHODS

Digital radiographs before and after reduction and CT images after reduction of 20 patients with a first-time shoulder dislocation were assessed by 6 observers. It was recorded whether they diagnosed a lesion at the greater tuberosity, a lesion at the glenoid rim, a Hill-Sachs lesion, or any other skeletal pathology. The average agreement among the investigators was evaluated, and radiographic diagnoses were compared with those based on CT images.

RESULTS

Of the 10 cases that presented with a glenoid rim fracture, each investigator had overlooked at least 1 fracture (range, 1-4) on the radiographs. No investigator had diagnosed all 8 Hill-Sachs lesions on the presented images. The average overall agreement among the investigators and corresponding sensitivity and specificity were calculated. Agreement of diagnoses based on radiographs with those based on CT images was lowest for glenoid rim fractures and Hill-Sachs lesions.

CONCLUSION

Radiographs seem inferior to CT scans for assessing osseous lesions especially at the glenoid rim. We suggest performing a CT scan of the shoulder after primary dislocation to apply the correct treatment early and potentially avoid further dislocations.