Bankart Repair Does Not Stabilize Glenohumeral Joints With 10% Glenoid Bone Loss. A Dynamic Radiostereometry Study of Glenohumeral Joint Kinematics

Anterior-inferior glenoid bone loss may affect the result of Bankart repair. This study aimed to compare the dynamic glenohumeral joint kinematics of Bankart repair following a labral lesion (Bankart lesion) with and without 10% glenoid bone loss. Dynamic radiostereometry was used to evaluate eight human specimens in five test conditions: The native glenohumeral joint, labral lesion, Bankart repair of the labral lesion, 10% glenoid bone loss (bone and labrum), and Bankart repair of the labral lesion with 10% glenoid bone loss. Kinematics were evaluated during an 80° external rotation of the glenohumeral joint at 30° and 60° abduction, with anterior-directed loads of 0-30 N. Following Bankart repair of a labral lesion, the mean humeral head center translated up to 9.9 mm more posterior (95% CI: -0.5 to 20.4) and 5.8 mm more superior (95% CI: 0.2 to 11.8) than the labral lesion. Bankart repair following 10% glenoid bone loss resulted in a posterior translation of up to 2.8 mm (95% CI: -6.6 to 1.0) and 2.7 mm more superior (95% CI: -2.2 to 7.6) than the 10% glenoid bone loss. Bankart repair of the 10% glenoid bone loss did not restore joint kinematics; the translation was significantly more anterior (max 9.9 mm, 95% CI: 1.4; 21.2) and inferior (max 7.1 mm, 95% CI: -0.2; 14.4) compared to the repair of the labral lesion. Compared to the native joint, Bankart repair restored joint kinematics after an isolated labral lesion, while the stabilizing effect of Bankart repair after 10% bone loss was poor and clinically insufficient.