A bony defect of the anterior glenoid is often observed in patients presenting with recurrent dislocation; when this defect is considerably large, bony reconstruction is indicated and results in long-term stabilization of the joint. Conventional procedures for restoring the glenoid surface are associated with numerous postoperative complications related to bone graft fixation. The aim of this study was to devise a novel technique for graft fixation in the context of a large anterior glenoid defect that might mitigate these complications, and to quantify the techniques ability to restore bony stability in the ovine shoulder.
Screw-free fixation techniques were assessed qualitatively and tested on mock glenoid defect models. The buckle-down technique, a novel method of graft fixation involving 3 suture anchors and a cortical fixation button, was selected for biomechanical investigation in the ovine glenohumeral joint. An Instron material testing apparatus anteriorly dislocated the ovine shoulder in the anatomically intact state (n=8), with the presence of a 30% by-width anterior defect of the glenoid (n=11), and following reconstruction of the defect with the buckle-down technique (n=11). Force-displacement curves were recorded and analyzed for each specimen to quantify the mean stability of each cohort. Statistical significance was assessed with Mann-Whitney U and Wilcoxon signed-rank tests.
The presence of a large glenoid defect was associated with a 65% to 80% reduction in joint stability parameters. Reconstruction of the glenoid surface with the buckle-down technique improved stability by 100% to 205%, through achieving up to 81% of the stability of the anatomically intact ovine glenohumeral joint. Stiffness of the reconstruction cohort was found to not be statistically significantly different from the intact cohort, whereas all other comparisons were significant (P<0.05). There were no instances of anchor pull-out or suture rupture.
The buckle-down technique presents a novel, biomechanically stable method for reconstruction of a large glenoid defect.