Erosion or fracture of the anteroinferior glenoid rim after dislocation
Glenoid bone loss refers to erosion of the anteroinferior glenoid rim, most often from repeated anterior shoulder dislocations or a bony Bankart fracture at the time of a first dislocation. Each episode can chip or grind away a little more bone, so the glenoid gradually loses the concave socket shape that normally helps contain the humeral head.
The amount of bone lost is one of the strongest predictors of recurrent instability and directly shapes surgical decision-making. Below a critical threshold, soft-tissue procedures like arthroscopic Bankart repair are reasonable, but beyond it the glenoid track becomes unstable and bony augmentation (e.g. Latarjet) is favoured to restore the glenoid arc and avoid high failure rates.
Bone loss is quantified on CT (often with 3D reconstruction) or MRI by comparing the deficient glenoid surface to the inferior glenoid circle, expressed as a percentage of glenoid width. This figure is then considered alongside any humeral-sided (Hill-Sachs) lesion using the glenoid track concept, since combined bipolar bone loss changes management more than either lesion alone.
Measurement technique and observer experience introduce real variability, and percentage cutoffs used in the literature are approximate thresholds rather than precise biological boundaries. Relying on bone loss percentage in isolation risks under- or over-treating patients whose instability is also driven by capsulolabral laxity, activity demands, or an unaccounted Hill-Sachs lesion.
This guide was auto-drafted and is pending editorial review.