Review Question - QID 218195

The congruent arc latarjet procedure will increase the length of the glenoid track the most in patients with significant anterior glenoid bone loss.

Traumatic anterior shoulder instability (TUBS) is a common and complex problem, particularly in younger contact athletes and military populations. It has been increasingly recognized as a bipolar problem, with consideration to address the humeral head hill-sachs lesion and the anterior glenoid/labrum. For this reason, the concept of on-track/off-track has been established. Off-track lesions are seen when the humeral head engages with the anterior glenoid, whereas on-track lesions do not engage. Both the size of the hill-sachs defect and the degree of anterior glenoid bone loss (glenoid track) are important to take into account when considering whether the lesion will engage. With increasing degrees of anterior glenoid bone loss, a bony procedure should be considered rather than a soft tissue capsulolabral stabilization. The latarjet is the most common solution in this setting, as the coracoid transfer increases the bony track and provides a sling mechanism for improved soft tissue stabilization. There are two variations of the latarjet procedure, the traditional and the congruent arc (Illustration A). The traditional version does not increase the glenoid track as much but is less prone to fracturing during screw insertion. The congruent arc version uses the inferior coracoid to lengthen the glenoid track by approximately 15mm and may be better in cases of severe bone loss.

Privitera et al. evaluated clinical outcomes following latarjet procedures in 73 contact athletes and noted that 8% experienced 1 or more postoperative dislocations. An additional 14% experienced feelings of instability without true dislocation, but pain and function scores were quite good. This said, only 49% returned to their preoperative activity level. Those with 2 or more stabilization procedures prior to latarjet had a lower likelihood of returning to sport.

Shaha et al. attempted to validate the glenoid track concept clinically in 57 shoulders by classifying them preoperatively as on-track or off-track. There were 10 recurrences after stabilization with 6/8 of the off-track patients (75%) having recurrence vs. 4/29 (8%) of the on-track patients. They noted that the predictive value of the off-track measurement was superior in predicting recurrence compared to the calculation of >20% bone loss.

Shin et al. studied values of critical anterior glenoid bone loss leading to glenohumeral instability after an arthroscopic bankart repair. In their study, 17.3% was the number that was noted as, "critical," by which functional outcomes decreased and patients had a higher rate of surgical failure after arthroscopic bankart repair. They reiterated that the degree of anterior glenoid bone loss should be carefully evaluated as patients with increasing degrees of bone loss have a higher risk for failure post-operatively.

Figure A shows an axial CT scan of the shoulder with significant anterior glenoid bone loss. Illustration A depicts the difference between the orientation of the traditional (left) and congruent arc (right) latarjet procedures. Illustration B depicts the Bristow procedure.

Incorrect Answers:
Answer 1: The traditional latarjet procedure involves transferring the undersurface of the coracoid so that it rests against the anterior glenoid, such that the lateral surface of the coracoid becomes the new glenoid track. Therefore, the glenoid track length is decreased compared to the congruent arc technique where the graft is rotated 90 degrees and the inferior coracoid becomes the track (Illustration A).
Answer 3: The Bristow procedure involves making an osteotomy of the distal 1 cm of the coracoid and affixing this directly onto the anteroinferior glenoid without changing the orientation (Illustration B). The increase in the glenoid track would be less compared to the congruent arc technique which typically adds around 15 mm.
Answer 4: Arthroscopic labral repair and capsular shift are indicated for patients who participate in contact sports, and in revision settings with subcritical bone loss and would not increase the glenoid track.
Answer 5: Arthroscopic labral repair and remplissage would increase the degree of rotation before the Hill-Sachs lesion engaged on the anterior glenoid but would not increase the glenoid track.