Management of Curvilinear Ossification at Posterior Inferior Glenoid Margin
Critical Diagnostic Clarification Required
You must first determine whether this represents a posterior glenoid lesion (rare) versus the more common anterior-inferior bony Bankart lesion that may appear posteriorly on certain radiographic projections. The term "posterior inferior margin" is anatomically unusual for typical traumatic instability patterns, as bony Bankart lesions classically involve the anteroinferior glenoid rim in up to 22% of first-time anterior shoulder dislocations 1, 2.
Immediate Imaging Algorithm
Obtain complete radiographic series including AP views in internal and external rotation PLUS mandatory axillary or scapular Y-view, as AP views alone frequently miss the true location and extent of glenoid pathology 3, 4.
Order MR arthrography as definitive imaging in the subacute/chronic phase (>2-3 weeks post-injury) when joint effusion has resolved, providing 86-100% sensitivity for labral injury detection and accurate bone loss quantification 4.
Consider CT arthrography if MRI is contraindicated, as it provides superior visualization of osseous abnormalities including glenoid rim fractures 4.
If truly posterior-inferior location is confirmed, evaluate for glenoid dysplasia using MRI/CT arthrography to detect posteroinferior glenoid deficiency, increased glenoid retroversion (>10°), and abnormally thickened posterior labrum 5.
Treatment Algorithm Based on Lesion Characteristics
For Anteroinferior Bony Bankart Lesions (Most Likely Scenario)
Acute lesions (<3 months from first dislocation):
Small fragments (<15-20% of glenoid diameter) that are anatomically reduced: Trial of non-operative management with immobilization followed by rotator cuff strengthening 2.
Fragments >15-20% of glenoid diameter OR high-risk patients (young, <35 years, contact athletes): Proceed directly to arthroscopic Bankart repair with bony fragment fixation using suture anchors 1, 2, 6.
Acute arthroscopic repair achieves superior outcomes with mean Rowe scores improving from 59 to 92 and only 2.4% redislocation rates at 4+ year follow-up 6.
Chronic lesions (>3 months):
Assess degree of fragment resorption and anterior glenoid bone loss on MR or CT arthrography 4, 2.
Minimal bone loss with intact fragment: Arthroscopic repair with suture anchor fixation, though outcomes are less favorable (Rowe scores 43.5 to 61) with 4.2% redislocation rates 6.
Significant bone loss (>20-25% of glenoid width): Requires bone grafting procedures—either anatomical reconstruction (iliac crest autograft, osteoarticular allograft) or non-anatomical procedures (Latarjet, Bristow) 2.
For True Posterior-Inferior Glenoid Pathology (Dysplasia)
Initial management: 3-6 months of physical therapy focusing on rotator cuff strengthening and proprioceptive control 5.
Persistent symptomatic posterior instability: Consider arthroscopic posterior labral repair and capsulorrhaphy 5.
Glenoid retroversion >10°: Soft-tissue-only procedures have high failure rates; may require glenoid osteotomy or bone grafting, though outcomes are unpredictable with substantial complication risks 5.
Critical Pitfalls to Avoid
Never rely on AP radiographs alone—over 60% of posterior dislocations and many glenoid rim fractures are missed without axillary or Y-views 3, 7.
Do not use non-contrast MRI in chronic cases without adequate joint effusion, as this results in suboptimal soft tissue assessment; MR arthrography is mandatory 4.
Underestimating bone loss on plain radiographs leads to inappropriate treatment selection; always obtain MR or CT arthrography for accurate quantification 4.
Delaying treatment in young, active patients with recurrent instability increases long-term glenoid bone loss and worsens surgical outcomes 1, 2.
Attempting arthroscopic repair alone with >20-25% bone loss results in high failure rates; these patients require bone grafting procedures 2.