Reconsidering “Critical” Bone Loss in Shoulder Instability: 17-Year Follow-Up Study following Arthroscopic Bankart Repair

Figure 2

Graphical representation of minimal critical, subcritical, and critical bone loss concepts. (a) Hemisphere represents humeral head and concavity represents glenoid cavity which is drawn with gridlines of one hundred squares (100%). Minimal critical bone loss, subcritical bone loss, and critical bone loss are represented by green, yellow, and red lines, respectively. A nonlinear relationship between glenoid cavity depth and glenoid width loss is observed. (b) In arthroscopic Bankart repair in patients with minimal critical bone loss, the repaired capsulolabral tissue (represented by a blue-white-blue oval curve) replaces the glenoid bony rim (as shown by the grey arrow). This reparative tissue is likely to be under higher pressure than capsulolabral tissue in a normal position which has the additional support of a normal glenoid bony rim. (c) With aging, the likelihood of recurrent shoulder dislocations reduces due, in part, to a decrease in elasticity of the capsular and extracapsular soft tissues (orange curve) [17, 18].

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