Glenoid bone loss resulting from either an acute shoulder dislocation or chronic osseous erosion due to reintrinsic stability of the glenohumeral joint1. Although long- term studies have demonstrated favorable results, in terms of stability and function, after autologous bone-grafting procedures such as the Latarjet procedure, arthritis remains a concern. Nonoptimal positioning (either too proud or too recessed) of the glenoid bone block has been identified as a potential cause of arthritis and shoulder pain following bone graft reconstruction of the glenoid.
Several autologous bone-grafting procedures, including the Latarjet (and modified Bristow) procedure as well as the use of iliac crest bone graft, have been described. However, neither method has been identified as clearly superior in the setting of recurrent instability and glenoid bone loss. Proponents of the iliac crest bone graft technique, which utilizes the inner table of the iliac crest, identify a theoretical advantage over the Latarjet procedure in terms of improved congruity of the glenoid as well as a limitless bone-graft size. Advocates of the Latarjet procedure have argued that glenoid conformity is not the most important factor in the treatment of glenoid bone loss. The original Latarjet procedure involves fixation of the coracoid to the glenoid so that the lateral edge of the coracoid becomes juxtaposed to the glenoid surface (Latarjet-LAT procedure). However, this traditional method of performing the Latarjet procedure was challenged by De Beer and Burkhart, who modified the technique by affixing the coracoid to the glenoid in a rotated position so that the inferior (deep) coracoid surface became contiguous with the glenoid surface (Latarjet-INF procedure). Proponents of that technique (the coracoid positioned with its inferior surface as the glenoid face) argue that it allows better articular surface congruity by matching the glenoid concavity, similar to the way that the concavity of the inner table of the iliac crest bone graft matches the glenoid concavity.
Articular conformity after bone-grafting procedures for the treatment of glenoid deficiency remains poorly defined, as does the bone-grafting solution that is optimal for restoration of glenohumeral contact pressures. We investigated the alterations in glenohumeral articular contact pressures in a glenoid bone-loss model to determine the optimal graft choice, orientation, and placement.
The purposes of our study were to determine changes in the magnitude and location of contact pressure after (1) creation of clinically relevant 15% and 30% anterior glenoid defects; (2) subsequent glenoid bone augmentation procedures with iliac crest bone graft or a Latarjet bone block; and (3) flush, proud, or recessed placement of each glenoid bone graft. In addition, we sought to determine the amount of glenoid bone reconstruction after use of either the Latarjet-LAT or the Latarjet-INF bone block. We hypothesized that a clinically relevant defect involving 30% of the glenoid surface area would increase articular contact pressure in the anteroinferior quadrant of the glenoid and that bone augmentation with either the iliac crest bone graft or the Latarjet-INF bone block in a flush position would best normalize articular contact pressures. We also hypothesized that augmentation with the Latarjet-INF bone block would provide glenoid bone reconstitution that was greater (closer to the intact state) than that provided by the Latarjet-LAT bone block.