Anterior shoulder instability — labrum and bone loss

MRI · CT

First and second year — the floor first, then every step

After an anterior dislocation: the anteroinferior labral tear (Bankart and variants), the Hill–Sachs lesion, and — what decides the operation — the amount of glenoid bone loss and whether the Hill–Sachs is on- or off-track.

Orient first

  • Bankart: anteroinferior labrum detached with the torn periosteum; ALPSA and Perthes are variants; bony Bankart includes a glenoid fragment.
  • Glenoid track concept: an off-track Hill–Sachs engages the glenoid rim and needs bone augmentation (verify method).
  • MR arthrography improves labral assessment; CT with 3D en-face glenoid measures bone loss.

Acquire the study

  • Axial, oblique coronal and oblique sagittal PD fat-saturated; T1 fat-saturated in ABER position for MR arthrography.

The manoeuvre

  • Axial images from 3 to 6 o'clock: anteroinferior labrum detachment and periosteal status.
  • HAGL on oblique coronal: humeral avulsion of the glenohumeral ligament.
  • Posterolateral humeral head on axial: Hill–Sachs impaction — depth and width in mm.
  • Oblique sagittal en-face glenoid: bone loss estimated with the best-fit circle in %.
  • Rotator cuff in older patients (dislocation tears the cuff).

What confirms it

  • Anteroinferior labral detachment with a Hill–Sachs lesion after a dislocation.

What licenses you to exclude it

  • An intact anteroinferior labrum and no Hill–Sachs on MR arthrography make a structural instability lesion unlikely.

The classic misread

  • Calling the sublabral foramen or Buford complex (anterosuperior) a tear.

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