Posterior side-to-side suture healing affects clinical and radiologic outcomes after arthroscopy-assisted lower trapezius transfer for posterosuperior irreparable rotator cuff tears.

PURPOSE: The purpose of this study was to evaluate the clinical and radiologic outcomes according to the healing status of posterior side-to-side suture after arthroscopy-assisted lower trapezius tendon transfer (aLTT) for posterosuperior irreparable rotator cuff tears (PSIRCTs).

METHODS

We retrospectively reviewed 117 patients with PSIRCTs who underwent aLTT between January 2019 and July 2022 and were followed for at least 3 years. The patients were classified into the healed group (n = 77) or the unhealed group (n = 40) according to the healing status of the posterior side-to-side suture. The primary outcome was the American Shoulder and Elbow Surgeons (ASES) score. Secondary outcomes included pain, other patient-reported outcome measures (PROMs), active range of motion (aROM) and aROM strength. Radiologic outcomes included acromiohumeral distance (AHD), Hamada grade and graft integrity. Multivariate logistic regression was performed to identify independent predictors of posterior side-to-side suture healing.

RESULTS

The ASES score was significantly higher in the healed group compared with the unhealed group at final follow-up (76.5 ± 12.6 vs. 65.7 ± 16.1, p = 0.001). Regarding secondary outcomes, the healed group achieved significantly higher Constant (p < 0.001), activities of daily living requiring active external rotation (ADLER) (p < 0.001) scores, forward elevation (FE) (p < 0.001), external rotation (ER) (p = 0.001), FE strength (p < 0.001) and ER strength (p < 0.001) compared with the unhealed group at final follow-up. The healed group demonstrated a significantly greater AHD compared with the unhealed group (8.9 ± 1.4 vs. 7.4 ± 1.6 mm, p < 0.001). The retear rate of the transferred tendon was also significantly lower in the healed group (6.5%) than in the unhealed group (55.0%) (p < 0.001). Multivariable analysis identified teres minor (Tm) fatty infiltration (FI) grade as the only independent predictor of posterior side-to-side suture healing (odds ratio [OR], 1.54; 95% confidence interval [CI], 1.03-2.30).

CONCLUSION

The healing of the posterior side-to-side suture was associated with favourable clinical and radiologic outcomes after aLTT. Furthermore, Tm FI grade was identified as the independent predictor of posterior side-to-side suture healing.

LEVEL OF EVIDENCE: Level IV case series.