Evolving concepts in the treatment of posterior shoulder instability with glenohumeral bone loss.

Posterior shoulder instability is an increasingly recognized phenomenon and comprises approximately 5% of all shoulder instability cases. Posterior shoulder instability presents a complex clinical challenge, particularly when associated with bone loss. Bone loss may be present in up to 25% of patients with posterior shoulder instability. Understanding its etiology, diagnosis, and treatment options is crucial for optimal patient outcomes. Young athletic individuals, especially football linemen and throwing athletes, are commonly affected, with symptoms ranging from insidious onset pain to noticeable changes in athletic performance. History, physical examination, and imaging, including radiographs and advanced three-dimensional imaging, play pivotal roles in diagnosis, with specific tests like the Jerk, Kim, and load and shift tests aiding in provocation. Posterior glenoid bone loss (pGBL), whether dysplastic, attritional, or acute, significantly impacts management decisions. When pGBL exceeds critical thresholds, soft tissue repair alone may be insufficient, necessitating glenoid reconstruction with bone block procedures. Both iliac crest autograft and distal tibial allograft (DTA) offer viable options, with considerations including donor site morbidity and graft integration. Surgical techniques for reverse Hill-Sachs lesions vary from subscapularis transfers to arthroscopic balloon osteoplasty, each aiming to restore native anatomy and prevent engagement. Bipolar bone loss, involving both glenoid and humeral head defects, presents additional challenges and may require combined soft tissue and bony procedures. Quantifying bone loss and understanding its implications are essential for surgical planning. While various techniques show promise, further research is needed to elucidate their long-term outcomes and refine treatment algorithms for posterior shoulder instability with bone loss.