Translation of the glenohumeral joint in patients with multidirectional and posterior instability: awake examination versus examination under anesthesia.

The purpose of this study was to assist in establishing guidelines to determine the degree of shoulder instability, the value of awake clinical examination, and the value of examination under anesthesia (EUA). Forty-three patients with clinical diagnosis of multidirectional shoulder instability (MDI) and 28 patients with posterior instability underwent bilateral shoulder translation testing, both awake and while under anesthesia. Two surgeons using guidelines and translation grades developed by the American Shoulder and Elbow Surgeons examined each patient and assigned a single grade for the anterior, posterior, and inferior directions. A comparison of translational grade was performed with the use of Pearson chi2 and McNemar symmetry to determine association. The patients with MDI showed increased translation in the anterior, inferior, and posterior directions when the affected limb was compared with the noninvolved side in both preoperative examination and EUA. Furthermore, the patients with MDI showed increased anterior translation on the affected side during EUA compared with the clinical examination. Patients with posterior instability demonstrated increased anterior translation for both affected and noninvolved limbs during EUA. However, the posterior translation obtained before surgery did not change during EUA for both the affected and noninvolved limbs, and there was no side-to-side difference in posterior translation.