Bone loss in shoulder instability: putting it all together.

Glenohumeral bone loss is frequently observed in cases of recurrent anterior and posterior shoulder instability and represents a risk factor for failure of nonoperative treatment. Patients with suspected glenoid or humeral bone loss in the setting of recurrent instability should be evaluated with a thorough history and physical examination, as well as advanced imaging including computed tomography (CT) and/or magnetic resonance imaging (MRI). In cases of both anterior and posterior instability, the magnitude and location of bone loss should be determined, as well as the relationship between the glenoid track (GT) and any humeral defects. While the degree and pattern of osseous deficiency help guide treatment, patient-specific risk factors for recurrent instability must also be considered when determining patient management. Treatment options for subcritical anterior bone loss include labral repair and capsular plication, while more severe deficiency should prompt consideration of bony augmentation including coracoid transfer or free bone block procedures. Concomitant humeral lesions are treated according to the degree of engagement with the glenoid rim and may be addressed with soft tissue remplissage or bony augmentation procedures. While critical and subcritical thresholds of glenoid bone loss guide the management of anterior instability, such thresholds are less defined in the setting of posterior instability. Furthermore, current treatment algorithms are limited by a lack of long-term comparative studies. Future high-quality studies as well as possible modifications in indications and surgical technique are required to elucidate the optimal treatment of anterior, posterior, and bipolar glenohumeral bone loss in the setting of recurrent shoulder instability.