DefinePK

Research Objective

To examine the diagnostic precision of axial and anteroposterior (AP) X-rays in identifying and measuring bone loss in patients with repeated shoulder dislocations.

Methodology

A comparative study involving 30 individuals with recurrent shoulder dislocations. Both axial and anteroposterior (AP) radiography were performed. Bone loss was measured in millimeters for the humeral head and as a percentage of the total glenoid surface area for the glenoid. Two radiologists evaluated the images for sensitivity, specificity, and accuracy. Inter-observer reliability was assessed using the Intraclass Correlation Coefficient (ICC), and overall diagnostic performance was evaluated using Receiver Operating Characteristic (ROC) curve analysis.

Methodology Flowchart

                        graph TD
    A["Recruitment of 30 patients with recurrent shoulder dislocations"] --> B["Perform AP and Axial X-rays"];
    B --> C["Measure Glenoid Bone Loss % of surface area"];
    B --> D["Measure Humeral Head Bone Loss mm"];
    C --> E["Radiologist Evaluation: Sensitivity, Specificity, Accuracy"];
    D --> E;
    E --> F["Calculate Inter-observer Reliability ICC"];
    E --> G["Perform ROC Curve Analysis AUC"];
    F --> H["Compare Diagnostic Performance of AP vs. Axial X-rays"];
    G --> H;
    H --> I["Conclusion on preferred imaging modality"];                    

Discussion

The study highlights the superior diagnostic capabilities of axial X-rays over AP X-rays in identifying and quantifying bone loss in recurrent shoulder dislocations. This improved accuracy is crucial for effective preoperative evaluation and treatment planning, particularly for procedures like the Latarjet or remplissage techniques. While axial X-rays involve slightly longer operating times and marginally higher radiation exposure, these factors are outweighed by their enhanced diagnostic performance.

Key Findings

Axial X-rays demonstrated significantly higher sensitivity (85%) and accuracy (83%) compared to AP X-rays (70% and 68%, respectively) for detecting bone loss. Axial X-rays also showed higher specificity (80% vs. 65%). Mean glenoid bone loss was 16.5% with axial X-rays versus 14.2% with AP X-rays. Mean humeral head bone loss was 5.6 mm with axial X-rays versus 4.8 mm with AP X-rays. Inter-observer reliability was better with axial X-rays (ICC 0.88 for glenoid, 0.85 for humeral head) compared to AP X-rays (ICC 0.75 for glenoid, 0.70 for humeral head). ROC analysis indicated better diagnostic performance for axial X-rays (AUC = 0.85 for glenoid, 0.82 for humeral head) compared to AP X-rays (AUC = 0.71 for glenoid, 0.69 for humeral head).

Conclusion

Axial X-rays are the preferred imaging modality for assessing bone loss in recurrent shoulder dislocations due to their superior sensitivity, specificity, accuracy, and inter-observer reliability compared to AP X-rays. This makes them more suitable for preoperative evaluation and guiding treatment decisions.

Fact Check

1. Sensitivity of Axial X-rays for Glenoid Bone Loss: The study reports a sensitivity of 85% for axial X-rays in detecting glenoid bone loss.
2. Mean Glenoid Bone Loss Measurement: Axial X-rays measured a mean glenoid bone loss of 16.5% ± 3.1%, while AP X-rays measured 14.2% ± 3.4%.
3. Inter-observer Reliability for Axial X-rays: The ICC for glenoid bone loss using axial X-rays was reported as 0.88, indicating excellent reliability.

Mind Map