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.

ABSTRACT

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 versus upper 2/3rd -lower 1/3rd split) and (2) the differences in elevation ROM, internal rotation ROM, the functional outcomes and the internal rotation 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 2/3rd -lower 1/3rd level split (LS group, n=19) versus mid-level split (MS group, n=13)] performed in the Latarjet-Walch procedure. RESULTS: The final ER1 (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=0.8) groups. The final ER2 (external rotation with the elbow abducted @ 90°) deficit was not significantly different between that of the LS (14° ± 12°) and the MS groups (12° ± 9°, p=0.5). Only in the MS group were the final ER1 deficit (p=0.03) and the final ER2 deficits (p=0.05) significantly better (smaller) than the corresponding baseline values. The Rowe scores (p=0.2) and the shoulder subjective value (p=0.7) 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 internal rotation strength was 95% of the normal, unaffected shoulder in the LS group and 93% of the normal in the MS group (p=0.6). Computed tomography (CT) 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=0.3) groups. CONCLUSION: We found no difference in final external rotation limitation between the upper 2/3rd - lower 1/3rd versus mid-level subscapularis split techniques. The functional outcomes, the internal rotation strength, subscapularis transverse diameter index, and fatty infiltration in the CT scan were similar in both groups.