Background: Glenoid bone defect is frequently associated with anterior shoulder instability and is considered one of the major causes of recurrence of instability after shoulder stabilization.
Hypothesis: Some risk factors are significantly associated with the presence, size, and type of glenoid bone defect.
Study Design: Cohort study (prognosis); Level of evidence, 2.
Methods: One hundred sixty-one patients affected by anterior shoulder instability underwent morphologic evaluation of the glenoid by computed tomography scans to assess the presence, size, and type of glenoid bone defect (erosion or bony Bankart lesion). Bone loss greater than 20% of the area of the inferior glenoid was considered “critical” bone defect (at risk of recurrence). Outcomes were correlated with the following predictors: age, gender, arm dominance, frequency of dislocation, age at first dislocation, timing from first dislocation, number of dislocations, cause of first dislocation, generalized ligamentous laxity, type of sport, and manual work.
Results: Glenoid bone defect was observed in 72% of the cases. Presence of the defect was significantly associated with recurrence of dislocation compared with a single episode of dislocation, increasing number of dislocations, male gender, and type of sport. Size of the defect was significantly associated with recurrent dislocation, increasing number of dislocations, timing from first dislocation, and manual work. Presence of a critical defect was significantly associated with number of dislocations and age at first dislocation. Bony Bankart lesion was significantly associated with male gender and age at first dislocation.
Conclusion: The number of dislocations and age at first dislocation are the most significant predictors of glenoid bone loss in anterior shoulder instability.
Background: Many authors have reported the presence of intra-articular lesions after primary dislocation of the shoulder joint. However, few studies have focused on their prevalence or the differences in accompanying lesions between primary and recurrent dislocations of the shoulder joint.
Purpose: This study was undertaken to investigate and analyze accompanying lesions, including types of anteroinferior labrum injuries, using diagnostic arthroscopy and magnetic resonance arthrography (MRA) in 144 patients with traumatic anterior dislocation of the shoulder joint.
Study Design: Cohort study; Level of evidence, 3.
Methods: There were 33 patients with 33 dislocations in the primary dislocation group and 111 patients with 111 dislocations in the recurrent dislocation group. Preoperative magnetic resonance arthrography and diagnostic arthroscopy were performed on all patients.
Results: In the primary dislocation group, 8 Bankart lesions, 9 free anterior labrum periosteal sleeve avulsion (ALPSA) lesions, 4 bony Bankart lesions, and 1 adhesive ALPSA lesion were observed. In the recurrent dislocation group, 68 Bankart lesions, 11 free ALPSA lesions, 13 bony Bankart lesions, 16 adhesive ALPSA lesions, and 1 glenoid articular rim disruption lesion were found. There were 22 (66.6%) and 109 (98.1%) patients with lesions in the anteroinferior labrum in the primary and recurrent groups, respectively. There was a statistically significant difference between the 2 groups (P = .002). Also, there was a significant difference between the 2 groups in the prevalence of the Hill-Sachs lesion and inverted pear-shaped glenoid lesion (P = .008/P = .047). Inverted pear-shaped glenoids were observed in 15 patients in the recurrent group. In 139 of 144 patients, surgical findings of accompanying lesions coincided with magnetic resonance arthrography findings (96.5%).
Conclusion: Various forms of anteroinferior labral lesions were seen in patients with traumatic anterior dislocation of shoulder. The recurrent dislocation group showed a significantly higher prevalence of anteroinferior labral lesions and bony lesions in comparison with the primary group. In our study, magnetic resonance arthrography was an accurate method to assess accompanying lesions in first-time and recurrent anterior dislocation of the shoulder, suggesting that this may be a useful tool for determining a treatment method.
