Subscapularis atrophy and function after arthroscopic Trillat procedure.

Introduction: Several studies have reported a strength deficit in internal rotation (IR) following a Latarjet procedure, which can persist for months or even years. The arthroscopic Trillat procedure does not require splitting the subscapularis muscle, potentially making it less damaging.

Hypothesis: The arthroscopic Trillat procedure does not cause any atrophy or strength deficit in the subscapularis muscle.

Methods: This was a single center, retrospective study of patients treated between 2013 and 2021. Included were patients who had chronic anterior shoulder instability with an indication for surgical stabilization using an arthroscopic Trillat procedure and who underwent a CT scan before surgery and a second one at 6 months postoperative. The following morphological parameters were measured on all the rotator cuff muscles: cross-sectional area (CSA), thickness and fatty infiltration using the mean muscle attenuation (MMA) measurement. Isokinetic tests were done 1 year post-surgery.

Results: One hundred seventeen patients underwent arthroscopic Trillat surgery between 2013 and 2021; 58 were included, 30 were analyzed and 17 patients underwent isokinetic testing. The CSA of the subscapularis was significantly smaller by 5.3% (17.0 vs. 16.1; p = 0.03). None of the other rotator cuff muscles had a smaller CSA. The MMA of the subscapularis increased significantly while the MMA of the external rotators decreased postoperatively. No strength deficit was found at 1 year postoperative in the internal and external rotators.

Discussion: The arthroscopic Trillat procedure produces minor atrophy of the subscapularis muscle at 6 months, with no strength deficit at 1 year postoperative. Several studies have reported a deficit in internal rotation strength after a Latarjet procedure, ranging from 6% to 19% depending on the study.

Level of evidence: IV.