Midterm Outcome of Arthroscopic-Assisted Lower Trapezius Transfer Using an Achilles Allograft in Treatment of Posterior Superior Irreparable Rotator Cuff Tear.

BACKGROUND: Arthroscopically-assisted lower trapezius tendon (aLTT) transfer is one of the treatment options for posterior superior irreparable rotator cuff tears (PSIRCTs). Although short-term clinical outcomes have shown promising results, there are currently no reported clinical outcomes over a longer follow-up period. This study evaluates the mid-term outcomes of aLTT transfer for patients diagnosed with PSIRCTs.

METHODS: This retrospective case series study included patients who underwent aLTT transfer between May 2017 and May 2019. The clinical outcomes assessment included the pain Visual Analog Scale (VAS), Constant score, American Shoulder and Elbow Surgeons (ASES) score, University of California Los Angeles (UCLA) score, Activities of Daily Living Requiring Active External Rotation (ADLER) score, active Range of Motion (aROM), Single Assessment Numeric Evaluation (SANE) score, and rates of return to work. The radiographic analysis included the acromiohumeral distance (AHD), Hamada grade, and integrity of the transferred tendon at the final follow-up. Subgroup analysis was done based on the integrity of the transferred tendon and the trophicity of the Teres minor (Tm).

RESULTS: This study enrolled 36 patients with a mean age of 63.4 years who met the inclusion criteria and were followed up for a mean of 58.2±5.3 months. At the final follow-up, the patients showed significant improvement in mean VAS, Constant, ASES, UCLA, ADLER, and aROM of all directions except internal rotation. Decrease in AHD and increase in Hamada grade were observed at final follow-up (P=0.040 and P=0.006, respectively). Seven patients experienced re-tear of the transferred tendon, and two individuals developed postoperative infections. Interestingly, re-tear group still demonstrated improvement in VAS scores, but failed to improve external rotation at the side by the final follow-up. Compared to the Tm non-hypertrophic group, Tm hypertrophic group showed significantly better improvement in external rotation at 90° abductions and at the side, as well as ADLER scores. 30 patients (83.3%) were able to successfully resume their previous work.

CONCLUSION: In this study, aLTT transfer in patients with PSIRCTs demonstrated significant improvements in clinical and radiologic outcomes by the final follow-up. These findings provide support for the mid-term safety and effectiveness of aLTT transfer as a viable joint-preserving treatment option for PSIRCTs. However, larger and longer-term studies are still needed to further validate these findings.