Effect of Posterior Glenoid Bone Loss and Retroversion on Arthroscopic Posterior Glenohumeral Stabilization

Abstract

Background: Posterior glenohumeral instability is an increasingly recognized cause of shoulder instability, but little is known about the incidence or effect of posterior glenoid bone loss. Purpose: To determine the incidence, characteristics, and failure rate of posterior glenoid deficiency in shoulders undergoing isolated arthroscopic posterior shoulder stabilization. Study Design: Cohort study; Level of evidence, 3. Methods: All patients undergoing isolated posterior labral repair and glenoid-based capsulorrhaphy with suture anchors between 2008 and 2016 at a single institution were identified. Posterior bone deficiency was calculated per the best-fit circle method along the inferior two-thirds of the glenoid by 2 independent observers. Patients were divided into 2 groups: minimal (0%-13.5%) and moderate (>13.5%) posterior bone loss. The primary outcome was reoperation for any reason. The secondary outcomes were military separation and placement on permanent restricted duty attributed to the operative shoulder. Results: A total of 66 shoulders met the inclusion criteria, with 10 going on to reoperation after a median follow-up of 16 months (range, 14-144 months). Of the total shoulders, 86% (57/66) had ≤13.5% bone loss and 14% (9/66) had >13.5%. Patients with moderate posterior glenoid bone loss had significantly greater retroversion (−11.5° vs −4.3°; P = .01). Clinical failure requiring reoperation was seen in 10.5% of patients in the minimal bone deficiency group and 44.4% in the moderate group ( P = .024). There was no difference between groups in rate of military separation or restricted duty. Patients with moderate posterior glenoid bone deficiency were more likely to be experiencing instability instead of pain on initial presentation ( P < .001), were more likely to have a positive Jerk test result ( P = .05), and had increased glenoid retroversion ( P = .01). Conclusion: In shoulders with moderate glenoid bone deficiency (>13.5%) and increased glenoid retroversion, posterior capsulolabral repair alone may result in higher reoperation rates than in shoulders without bone deficiency.

Prospective Evaluation of Posterior Glenoid Bone Loss After First-time and Recurrent Posterior Glenohumeral Instability Events

“…Risk factors for recurrence of posterior instability include age <40 years at the first instability event, dislocation due to seizure, large reverse Hill-Sachs lesion, and increased glenoid retroversion. 5,29,35 Several studies have shown a relationship between glenoid bone loss and increased risk of recurrent instability after posterior labral repair 4,41 ; however, glenoid bone loss has not been shown to be a risk factor in other studies. 9,20 Whereas for anterior instability there is a generally well-accepted understanding of the critical amount of glenoid bone loss at which capsulolabral repair alone would not be sufficient, 3,11,12,24,36,37 this is not the case for posterior instability.…”

“…9,20 Whereas for anterior instability there is a generally well-accepted understanding of the critical amount of glenoid bone loss at which capsulolabral repair alone would not be sufficient, 3,11,12,24,36,37 this is not the case for posterior instability. One study showed that the critical amount of posterior glenoid bone loss was >13.5%, 41 and a biomechanical model suggested that bony augmentation would be necessary with >20% of posterior glenoid bone loss. 27 Despite this, the natural history of posterior glenoid bone loss and its role in the surgical management of posterior glenohumeral instability remain poorly understood.…”

Single-Portal Arthroscopic Posterior Capsulorrhaphy for Recurrent Shoulder Capsule Laxity and Instability

“…Given the intra-articular establishment of 2 suture anchors in the glenoid cavity for capsular closure, proper portal placement must be ensured to avoid unnecessary glenoid bone loss. In a 2020 study of patients undergoing arthroscopic posterior glenohumeral stabilization procedures, Wolfe et al 21 found that patients with moderate posterior glenoid bone deficiency had a significantly higher rate of reoperation (P ¼ .024), had increased glenoid retroversion (P ¼ .01), had instability instead of pain on initial presentation (P < .001), and had positive jerk test results (P ¼ .01). Furthermore, in a 2018 study of patients who underwent arthroscopic isolated stabilization of the posterior labrum at a single military treatment facility, Hines et al 22 showed those with subcortical bone loss greater than 13.5% were statistically less likely to return to full duty.…”

Editorial Commentary: Posterior Shoulder Instability Surgical Treatment Outcomes Are Inferior to Outcomes of Anterior Instability: Standardization of Patient Evaluation and Indications Could Improve Results

“…See related article on page 551 P osterior shoulder instability is an increasingly recognized pathologic condition of the shoulder. [1][2][3][4][5] It is commonly observed in young collision and overhead athletes, especially with flexion, external rotation, overhead and forward pressing, and pushing activities. Cognetti, Hughes, Kay, Chasteen, Fox, Hartzler, Lin, and Sheean should be congratulated for their Level IV systematic review, "Bone Block Augmentation of the Posterior Glenoid for Recurrent Posterior Shoulder Instability Is Associated With High Rates of Clinical Failure."…”

“…6 There is a continued and persistent problem in the setting of posterior instability when there is significant posterior retroversion, whether it is either acquired or congenital. 2,7,8 This is the usual case in which a posterior bone block is used; however, the outcomes have been mixed, at best. 6,[9][10][11] While arthroscopic capsulolabral repair remains the mainstay of treatment in refractory cases for posterior instability, associated postoperative complications can still occur.…”