The appropriate audience to review this material would be a peer-review panel consisting of Fellowship-Trained Musculoskeletal (MSK) Radiologists and Orthopedic Shoulder Surgeons.
Following is the summary of the material from the perspective of a Senior MSK Imaging Consultant.
Abstract:
This clinical synthesis addresses the diagnostic complexities involved in differentiating normal anatomic variants of the superior glenoid labrum from pathologic Superior Labrum Anterior-Posterior (SLAP) lesions. Utilizing MR Arthrography (MRA) and arthroscopic correlation, the material details the "pear-shaped" (or avocado-shaped) morphology of the glenoid and the mechanics of the Periarticular Fiber System (PAFS), which acts as a tension brace transmitting forces to the labrum.
The presentation provides a comprehensive taxonomy of anatomic variants—including the sublabral recess, sublabral foramen, and Buford complex—and establishes criteria to prevent the overdiagnosis of SLAP lesions, particularly Type I (degenerative fraying). The classification of SLAP lesions is expanded from Snyder’s original four types to ten distinct categories based on morphology, extent, and involvement of adjacent structures like the long head of the biceps tendon (LHBT) and glenohumeral ligaments. Critical imaging signs, such as the "double oreo" and "cheerio" signs for Type III lesions, are defined alongside secondary pathologic indicators like paralabral ganglion cysts and "chondral prints." The material concludes with a summary of treatment algorithms, ranging from debridement and labral repair to biceps tenodesis.
Clinical Synthesis: Superior Labral Anatomy, Variants, and Pathology
[0:00] Index Case and Diagnostic Challenge: A 22-year-old softball pitcher presents with a SLAP IV lesion (bucket-handle tear involving the LHBT). The central challenge is distinguishing such pathology from asymptomatic anatomic variants.
[2:55] Anatomy of the Glenoid Cavity: The glenoid develops from superior (subcoracoid) and inferior ossification centers. Fusion failures can result in the Glenoid Articular Rim Divot (GARD) lesion, typically at the 9–10 o’clock position, often confused with osteochondritis dissecans.
[5:45] Periarticular Fiber System (PAFS): The PAFS connects circumferential labral collagen to ligaments and tendons. In overhead athletes, the "peel-back" mechanism during abduction and external rotation shifts the force vector posterosuperiorly, initiating SLAP tears.
[9:07] Biceps-Labral Complex (BLC) Variations: There are four types of LHBT attachments. Type 1 and 2 (posterosuperior dominance) are most common (55%). Morphology is categorized as "slab" (adherent) or "meniscoid" (mobile with a sublabral recess).
[12:15] Primary Anatomic Variants:
Sublabral Recess: A smooth, medial-pointing space (<2mm) between the superior labrum and glenoid, typically not extending posterior to the biceps anchor.
Sublabral Foramen: An anterosuperior gap (1–3 o'clock) where the labrum is detached from the rim but reconnects via a labral slip at or above the 3 o'clock position.
Buford Complex: Characterized by a cord-like middle glenohumeral ligament (MGHL) and a completely absent anterosuperior labrum.
[22:00] SLAP Lesion Classification (Types I-X):
Type I: Degenerative fraying; considered universal in aging and often overdiagnosed as clinical pathology.
Type II: Detachment of the BLC (IIa: anterior; IIb: posterior; IIc: global).
Type III/IV: Bucket-handle tears. Type III spares the LHBT; Type IV involves it.
Type V: Bankart lesion extending superiorly to include a SLAP tear.
Type VI: Unstable flap tears.
Type VII-X: Extensions involving the MGHL (VII), posterior labrum (VIII), global labrum (IX), or rotator interval/SGHL (X).
[25:31] Diagnostic "Oreo" and "Cheerio" Signs: In SLAP III bucket-handle tears, MRA reveals the "double oreo" sign (two columns of contrast: one in the sublabral recess, one in the labral substance). The "cheerio" sign represents contrast encircling the displaced labral fragment.
[33:15] Clinical Orthopedic Correlation: Physical maneuvers including the O’Brien Active Compression, Speed, and Yergason tests show high specificity (especially Yergason at 93%) but variable sensitivity, necessitating MRA for definitive diagnosis.
[39:45] Associated Pathologic Findings:
Paralabral Ganglion Cysts: Highly predictive (59–88%) of labral tears. Large cysts in the spinoglenoid notch can cause suprascapular nerve entrapment and infraspinatus atrophy.
Chondral Print: Mechanical erosion on the humeral head articular surface caused by labral instability.
Pitcher’s Mound: A chronic bone excrescence on the superior glenoid resulting from a prior labro-osseous avulsion.
[Conclusion] Management and Treatment Trends: Type I lesions require only debridement. Type II management is shifting from suture anchors to biceps tenodesis in older/less active patients. Types III–X generally require surgical stabilization, repair, or tenodesis depending on the specific structures involved. Clinical reports should prioritize morphology and location over Roman numeral classification.