Is the Graft Position Critical for Functional Outcomes Following Arthroscopy-Assisted Lower Trapezius Tendon Transfer for Posterosuperior Irreparable Rotator Cuff Tears? A Comparison of Anterior vs. Posterior Position of Graft.

Abstract

Arthroscopy-assisted lower trapezius tendon transfer (aLTT) has emerged as a reasonable treatment option for posterosuperior irreparable rotator cuff tears (PSIRCTs) due to its biomechanical advantages and favorable clinical outcomes. Although there are various surgical techniques for aLTT, the optimal positioning of the graft on the humeral head footprint is unknown in aLTT. This study aimed to evaluate clinical and radiological outcomes based on the interpositional graft position of aLTT graft in PSIRCTs. Patients who underwent aLTT for PSIRCTs from 2017 to 2022 were retrospectively analyzed, with a minimum follow-up period of 2 years. Patients were classified into Anterior group (n=44) if the interpositional graft was in the anterior position (supraspinatus footprint) or Posterior group (n=68) if it was in the posterior position (infraspinatus footprint) on postoperative magnetic resonance image. Clinical outcomes were evaluated with the visual analog scale (VAS) score, patient-reported outcome measurements (PROMs), active range of motion (aROM), and aROM strength. Radiological outcomes were evaluated by the acromiohumeral distance (AHD), Hamada grade, progression of osteoarthritis (OA), and acromial wear. Although both groups showed significant postoperative improvements in clinical outcomes, the postoperative forward elevation (FE, 160.2˚ ± 28.3˚ vs 150.4˚ ± 22.0˚, p = 0.037) of the Anterior group were significantly higher than that of the Posterior group. Moreover, the postoperative FE strength (27.4 ± 4.5 vs 24.4 ± 4.4, p = 0.037) of the Anterior group were significantly higher than that of the Posterior group. Postoperatively, AHD significantly increased in the Anterior group, whereas no significant change was observed in the Posterior group. The achievement of minimal clinical importance difference for AHD (68.2% vs 45.6%, p = 0.021) were significantly better in the Anterior group. Although the Posterior group demonstrated a numerically higher rate of progression of osteoarthritis and acromial wear, the difference was not statistically significant. aLTT showed significant postoperative clinical improvement regardless of the interpositional graft position in patients with PSIRCTs. However, attaching the interpositional graft to the supraspinatus footprint is thought to provide dynamic stability and static stability in subacromial space, leading to favorable outcomes. Therefore, unless the posterior remnant cuff is insufficient for posterior side-to-side suturing, it is recommended to place the graft as anteriorly as possible.