Hip Labral Tear MRI Signs: FAI, MR Arthrogram, and Paralabral Cysts

A meta-analysis reported sensitivity of 66% for conventional MRI and 87% for MR arthrography in detecting acetabular labral tears; specificity was 79% and 64%, respectively.

Radial reformats are oblique MRI sequences acquired in a series of planes oriented radially around the femoral neck, typically at 8 to 12 positions spanning the full circumference. Each reformat is perpendicular to the femoral neck axis at a given clock-face position, providing an orthogonal view of the head-neck junction and adjacent labrum at that location. This approach eliminates the partial-volume averaging that degrades standard axial and coronal images at the anterior and posterior margins of the hip. Radial reformats allow precise alpha angle measurement at the site of maximum cam deformity and improve detection of anterosuperior labral tears and associated cartilage delamination — pathology frequently missed on conventional MRA planes alone.

MRI can show labral signal abnormality, detachment, paralabral cysts, adjacent cartilage injury, and indirect signs of impingement. MR arthrogram can make some tears more conspicuous because contrast enters the tear plane. Imaging still needs clinician review alongside symptoms, examination, and prior treatment history.

X-ray and CT generally do not visualize the acetabular labrum directly. They are still useful because they show the bony drivers that often accompany labral injury: cam-type femoral head-neck offset, pincer overcoverage, acetabular dysplasia, version abnormalities, arthritis, or subtle fracture. MRI or MR arthrogram is needed when the clinical question is the labrum, cartilage, paralabral cysts, or fluid tracking into a tear.

CT is better for three-dimensional bony morphology, version, cortical fracture detail, and surgical planning around cam or pincer correction. MRI is better for the labrum, cartilage, marrow edema, and soft tissues. CT should complement the clinical and MRI picture rather than replace it for labral questions.

A clinician should confirm that symptoms fit an intra-articular hip source, review range of motion and provocative tests, evaluate FAI or dysplasia, assess cartilage status, and decide whether the imaging finding is incidental or likely responsible for the patient's pain. Imaging alone cannot prove symptom causation.

Labral tears may be incidental, so symptoms, examination and sometimes diagnostic injections help establish their importance. AI cannot identify the pain source or decide whether arthroscopy is appropriate.

Small, stable labral tears without associated FAI morphology may become asymptomatic with conservative management — targeted physical therapy to improve hip rotator strength and neuromuscular control, activity modification, and intra-articular corticosteroid or platelet-rich plasma injections. However, the labrum has limited intrinsic healing capacity due to its largely avascular fibrocartilaginous composition, particularly in the inner two-thirds. Tears associated with cam or pincer impingement are subject to ongoing mechanical stress and rarely resolve without addressing the underlying bony morphology. Arthroscopic labral repair, combined with cam resection or acetabuloplasty when indicated, restores biomechanical function and achieves good-to-excellent outcomes in appropriately selected patients.