Ultrasound-Guided Targeted Injection to the Anterior Labral-Ligamentous Complex of the Shoulder: A Cadaveric...

The anterior labral-ligamentous complex (ALLC), formed by the integration of the anterior inferior glenohumeral ligament and anterior glenoid labrum, plays a critical role in shoulder stability and represents a potential target for regenerative injection therapy. However, precise ultrasound-guided targeting of this capsular-labral interface has not been anatomically validated. This feasibility cadaveric study evaluated the accuracy of ultrasound-guided in-plane injection directed at the ALLC at its glenoid attachment. A fresh-frozen human cadaver specimen was examined in the supine position with the shoulder in external rotation. Stepwise lateral-to-medial and cranial-to-caudal ultrasound scanning was performed to localize the ALLC. A 23-gauge needle was advanced in a cranial-to-caudal in-plane trajectory, and 1-2 mL of red filler was injected into the capsular-labral interface. Subsequent layer-by-layer dissection was conducted to assess injectate localization. In both shoulders (2/2), red filler was confined within the ALLC without extra-capsular leakage, diffuse intra-articular pooling, or neurovascular staining. These findings demonstrate the anatomical feasibility of ultrasound-guided targeted delivery to the anterior capsular-labral complex. This proof-of-concept study provides foundational anatomical validation for the development of regenerative injection protocols directed at the shoulder capsular-labral enthesis.