Bone loss in patients with posterior gleno-humeral instability: a systematic review

The aim of this systematic review was to analyse outcomes of surgical procedures for glenoid and/or humeral bony defects, performed singularly or in combination, in patients with posterior gleno-humeral instability. A secondary aim was to establish in clinical settings which percentage of glenoid or humeral bone loss should be treated with a bony procedure to avoid recurrence of dislocation.

A systematic review of the literature according to the PRISMA guidelines was performed. A comprehensive search of PubMed, Medline, CINAHL, Cochrane, Embase, Ovid, and Google Scholar databases was performed using various combinations of the keywords "shoulder", "posterior instability", "dislocation", "bone loss", "reversed bony Bankart", "osseous glenoid defects", "glenoid bone grafting", "glenoid", "humeral head", "surgery", "gleno-humeral", "reversed Hill-Sachs", over the years 1966-2014. Data were independently extracted by all the investigators: demographics, previous surgery, imaging assessment, bone defect measurement, diagnosis, surgical management, return to sport, complications, and outcome measurements. The outcome parameters were recurrence of dislocation and clinical scores.

Nineteen articles, describing patients with glenoid bony defects, humeral bony defects, or both in the setting of posterior gleno-humeral instability were included. A total of 328 shoulders in 321 patients were included, with a median age at surgery of 33.4 years, ranging from 14 to 79 years. Patients were assessed at a median follow-up period of 3.6 years (ranging from 8 months to 22 years). A redislocation event occurred in 32 (10 %) shoulders. The redislocation event occurred in 2 (10 %) of 20 shoulders with glenoid bony defect and in 12 (11 %) of 114 shoulders with humeral bony defect.

Even though the general principle of treating recognized glenoid and humeral bone defects in patients with posterior gleno-humeral instability is widely accepted, to date few studies in the literature accurately establish which bone defects should be treated with bony procedures and the exact correlation between percentage of bone loss and higher risk of redislocation in clinical settings. A limitation to the present systematic review is the small number of included patients, due to the rare entity of posterior bone defects/reversed Hill-Sachs. The clinical relevance is that the results of this systematic review can be helpful to guide clinicians in the management of patients with posterior gleno-humeral instability and glenoid and/or humeral bony defects. This manuscript also highlights the need for accurate description of results in further investigations. The main drawback of the available articles in the topic is that they rarely clarify the percentage of bone loss in patients undergoing a redislocation event.

IV.