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An acetabular labral tear involves disruption of the fibrocartilaginous labrum that rims the acetabulum. This structure deepens the hip socket and contributes to joint stability and fluid sealing. Tears are associated with hip pain, mechanical symptoms (e.g., clicking, catching), and potential progression to early osteoarthritis.

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Classification

Radiological classification:

Location: Anterior > superior > posterior (anterior tears are most common).

Type	Description	Imaging Clue
Degeneration	Signal change without discrete tear	Intermediate signal without contrast penetration
Intrasubstance tear	Clefts or fissures within labrum	Linear contrast within labral tissue
Detachment	Separation from acetabular rim	Contrast between labrum and acetabulum
Complex tear	Combo of above	Multiple signal planes and irregularity

![Schematics show labral tears. A, Normal labrum. B, Intrasubstance labral tear. C, Partial-thickness labral tear. D, Full-thickness labral tear

Illustration copyright: University of Rochester Nguyen MS, Kheyfits V, Giordano BD, Dieudonne G, Monu JUV. Hip Anatomic Variants That May Mimic Abnormalities at MRI: Labral Variants. American Journal of Roentgenology. 2013;201(3):W394-W400. doi:10.2214/ajr.12.9860](attachment:0d0cc13c-11ec-4f34-aeef-be7e3340dd8b:image.png)

Schematics show labral tears. A, Normal labrum. B, Intrasubstance labral tear. C, Partial-thickness labral tear. D, Full-thickness labral tear

Blankenbaker clock face classification:

![Blankenbaker clock face of labral tears. A and B, Drawings show how Blankenbaker system uses clock face to describe location of acetabular findings. By convention, 3-o’clock position is anterior; 9 o’clock, posterior; 12 o’clock, superior; and 6 o’clock, inferior. Clock positions are same whether left (A) or right (B) acetabulum is used

Illustration copyright University of Rochester. Nguyen MS, Kheyfits V, Giordano BD, Dieudonne G, Monu JUV. Hip Anatomic Variants That May Mimic Abnormalities at MRI: Labral Variants. American Journal of Roentgenology. 2013;201(3):W394-W400. doi:10.2214/ajr.12.9860](attachment:146f3837-9aa9-40cd-bf05-afd671e55bad:image.png)

Blankenbaker clock face of labral tears. A and B, Drawings show how Blankenbaker system uses clock face to describe location of acetabular findings. By convention, 3-o’clock position is anterior; 9 o’clock, posterior; 12 o’clock, superior; and 6 o’clock, inferior. Clock positions are same whether left (A) or right (B) acetabulum is used

Lage arthroscopic classification

Etiology

Associated conditions:

Femoroacetabular impingement (FAI) syndrome: Most common cause; cam and pincer types cause repeated stress on the labrum.
Developmental dysplasia of hip (DDH): Shallow acetabulum leads to increased shear forces.
Trauma: Often in athletes, dancers, or after dislocation.
Degeneration: With aging or chronic overuse.

Radiology

https://doi.org/10.2214/AJR.12.9860