Recurrent Anterior Shoulder Instability With Combined Bone Loss
Authors: Yang Justin S. , Mazzocca Augustus D. , Cote Mark P. , Edgar Cory M. , Arciero Robert A. 
Published: February 2016

Background:

Recurrent anterior glenohumeral dislocation in the setting of an engaging Hill-Sachs lesion is high. The Latarjet procedure has been well described for restoring glenohumeral stability in patients with >25% glenoid bone loss. However, the treatment for patients with combined humeral head and mild (<25%) glenoid bone loss remains unclear.

Purpose/Hypothesis:

This study reports on the outcomes of the modified Latarjet for patients with combined humeral and glenoid defects and compares the results for patients with ≤25% glenoid bone loss versus patients with >25% glenoid bone loss. The hypothesis was that the 2 groups would have equivalent subjective outcomes and recurrence rates.

Study Design:

Cohort Study; Level of evidence, 3.

Methods:

Modified Latarjet was performed in 40 patients with recurrent anterior shoulder instability, engaging Hill-Sachs by examination confirmed with arthroscopy, and ≤25% anterior glenoid bone loss (group A). A second group of 12 patients were identified to have >25% glenoid bone loss with an engaging Hill-Sachs lesion (group B). The mean follow-up time was 3.5 years. All patients were assessed for their risk of recurrence using the Instability Severity Index score and Beighton score and had preoperative 3-dimensional imaging to assess humeral and glenoid bone loss. Single Assessment Numeric Evaluation (SANE), Western Ontario Shoulder Instability Index (WOSI), recurrence rate, radiographs, range of motion, and dynamometer strength were used to assess outcomes. A multivariate analysis was performed.

Results:

Glenoid bone loss averaged 15% in group A compared with 34% in group B. Both groups had comparable WOSI scores (356 vs 475; P = .311). In multivariate analysis, the number of previous surgeries and Beighton score were directly correlated with WOSI score in Latarjet patients. The SANE score was better in group A (86 vs 77; P = .02). Group B experienced more loss of external rotation (9.2° vs 15.8°; P = .0001) and weaker thumbs-down abduction and external rotation strength ( P < .032). Subscapularis, abduction, and external rotation strength averaged at least 75% of the contralateral shoulder in both groups. Graft resorption was similar in both groups (32% vs 33%; P < .999). The overall recurrent instability rate for the study, defined as any subsequent subluxations or dislocation, was 15%; recurrent instability rates (15% vs 17%; P > .999) were similar for both groups. The complication rate was 25% for both groups.

Conclusion:

The modified Latarjet procedure provides satisfactory outcomes for patients with combined bone loss, which is known to have high recurrence rates with traditional arthroscopic stabilization. Previous surgical stabilization procedures and the Beighton score adversely affect outcome after modified Latarjet. Furthermore, the number of previous surgeries and Beighton score can be used to predict WOSI score in Latarjet patients. Further study is needed to determine if these results hold true in the long term.