Splitting the subscapularis at the upper two-third and lower one-third junction or in the middle during the Latarjet-Walch procedure does not affect the external rotation range of motion.

Background: Our purpose was to investigate (1) the difference in external rotation range of motion (ROM) limitation between the two recommended subscapularis-splitting techniques (mid-split vs. upper 2/3 -lower 1/3 split) and (2) the differences in elevation ROM, internal rotation (IR) ROM, the functional outcomes and the IR strength between the two techniques in the Latarjet-Walch procedure.

Material And Methods: We conducted a prospective cohort study of patients with recurrent shoulder instability treated by the Latarjet-Walch procedure between January 2021 and January 2022. After a priori calculation of sample size, 32 patients were divided into two groups according to the type of intraoperative subscapularis split [upper 2/3 -lower 1/3 level split (LS group, n = 19) vs. mid-LS (MS group, n = 13)] performed in the Latarjet-Walch procedure.

Results: The final external rotation with the arm adducted deficit (as compared to opposite normal shoulder) was not significantly different between the LS (9° ± 8°) and the MS (10° ± 8°, P = .8) groups. The final ER with the elbow abducted @ 90° (ER2) deficit was not significantly different between that of the LS (14° ± 12°) and the MS groups (12° ± 9°, P = .5). Only in the MS group were the final ER with the arm adducted deficit (P = .03) and the final ER with the elbow abducted @ 90° deficits (P = .05) significantly better (smaller) than the corresponding baseline values. The Rowe scores (P = .2) and the Shoulder Subjective Value (P = .7) were not significantly different between the two groups. There were no postoperative subluxations in either group. However, 3 patients tested positive in apprehension testing in the LS group compared to none in the MS group, the difference being statistically insignificant. The IR strength was 95% of the normal, unaffected shoulder in the LS group and 93% of the normal in the MS group (P = .6). Computed tomography scan evaluation showed that the transverse diameter index of subscapularis (upper subscapularis diameter/lower subscapularis diameter) was not different in the MS (0.9 ± 0.1) and the LS (0.9 ± 0.1, P = .3) groups.

Conclusion: We found no difference in final external rotation limitation between the upper 2/3 - lower 1/3 vs. mid-level subscapularis split techniques. The functional outcomes, the IR strength, subscapularis transverse diameter index, and fatty infiltration in the computed tomography scan were similar in both groups.