A 52-year-old woman presents to the orthopedic clinic with a 6-week history of right shoulder pain following a fall on an outstretched hand (FOOSH injury). Initial plain radiographs (AP, lateral, and axillary views) obtained at the time of injury were reported as normal. She now complains of persistent pain and restricted shoulder motion. On examination, there is tenderness over the anterior shoulder and positive apprehension test. A repeat AP radiograph shows a subtle lucency in the anteroinferior glenoid rim. What is the most likely diagnosis, and which imaging modality would best characterize this lesion for surgical planning?

Explanation

## Clinical Scenario Interpretation This patient has a classic presentation of **anterior shoulder instability with a Bankart lesion** (anteroinferior glenoid rim fracture). The key clinical features are: - FOOSH injury with initial normal radiographs (occult fracture) - Persistent pain and restricted motion at 6 weeks - Positive apprehension test (classic for anterior instability) - Repeat radiograph showing subtle lucency in the anteroinferior glenoid ## Bankart Lesion: Definition and Imaging **Key Point:** A Bankart lesion is an avulsion fracture of the anteroinferior glenoid labrum and bone, occurring in 80–90% of first-time anterior shoulder dislocations. It is the primary cause of recurrent anterior instability. **High-Yield:** Plain radiographs (especially the West Point view or Stryker notch view) may show the lesion, but **CT with 3D reconstruction is the gold standard for characterizing Bankart lesions** because it: 1. Defines the size, location, and orientation of the fragment 2. Assesses glenoid bone loss percentage (critical for surgical planning) 3. Guides the choice between arthroscopic repair, open repair, or bone-block procedures ## Imaging Comparison for Anterior Shoulder Instability | Imaging Modality | Sensitivity for Bankart | Sensitivity for Hill-Sachs | Best Use | |---|---|---|---| | **Plain radiographs** | 50–60% (may be occult) | 60–70% | Initial screening | | **CT with 3D** | 95–100% | 95–100% | **Gold standard for surgical planning** | | **MRI (MR arthrography)** | 90–95% | 90–95% | Soft-tissue detail; labral pathology | | **Ultrasound** | 70–80% (operator-dependent) | Not ideal | Real-time assessment; limited in bony detail | ## Clinical Pearl **Occult Bankart lesions are common.** Initial radiographs may appear normal, but repeat imaging or dedicated views (West Point, Stryker notch, or axillary) often reveal the lesion. CT with 3D reconstruction is essential for surgical planning because: - Glenoid bone loss >25% typically requires bone-block augmentation (Latarjet procedure) - Glenoid bone loss <25% can be managed with arthroscopic repair alone - Fragment size and location determine the surgical approach ## Why CT Is Superior for This Case ```mermaid flowchart TD A[Anterior shoulder instability suspected]:::outcome A --> B[Plain radiographs]:::action B --> C{Bankart lesion visible?}:::decision C -->|Yes, simple| D[Arthroscopic repair]:::action C -->|No or complex| E[CT with 3D reconstruction]:::action E --> F{Glenoid bone loss >25%?}:::decision F -->|Yes| G[Latarjet or bone-block procedure]:::action F -->|No| H[Arthroscopic repair]:::action G --> I[Surgical planning complete]:::outcome H --> I ``` [cite:Rockwood and Green's Fractures in Adults Ch 13; Orthopedic Surgery Essentials: Shoulder]