LOWER TRAPEZIUS TENDON TRANSFER FOR MASSIVE IRREPARABLE ROTATOR CUFF TEARS IMPROVES OUTCOMES IN PATIENTS WITH HIGH-GRADE FATTY INFILTRATION OF TERES MINOR

Surgical management of massive irreparable rotator cuff tears has increasingly used salvage procedures such as tendon transfers to preserve glenohumeral articulation. Appropriate patient selection is crucial, yet there is a paucity of evidence investigating factors leading to improved outcomes. Success of latissimus dorsi tendon transfer (LDTT) has been linked to low levels of fatty infiltration of the teres minor (TM) muscle. However, the effect of TM fatty infiltration has not been studied in newer techniques such as lower trapezius tendon transfers (LTTT). This study aims to correlate post-operative outcomes of LTTT in massive irreparable rotator cuff tears to the degree of TM fatty infiltration. In this prospective longitudinal observational study, patients with massive rotator cuff tears undergoing arthroscopic-assisted LTTT by a single surgeon were screened. For all consented patients, TM fatty infiltration on pre-operative MRI was graded using the Goutallier classification by two orthopaedic surgeons not involved in the surgery. Two groups were created based on TM fatty infiltration: Group A included Grades 0 and 1 (no or little fatty infiltration) and Group B included Grades 2 to 4 (moderate to severe fatty infiltration). Participants completed the SANE score and satisfaction questionnaire at pre-, 12- and/or 24-months post-operative along with a clinical assessment. Between group comparisons were performed using independent t-tests assuming unequal variance and pre- vs post-operative comparisons were performed for each group using paired t-tests. Rate of external rotation (ER) lag sign was compared between groups using Fisher's exact test. Significance was defined as p < 0.05. Twenty-six patients met inclusion criteria, with 18 patients in Group A and 8 in Group B. There were no differences between groups with respect to pre-operative SANE score, degrees of active forward elevation or degrees of active ER. Eight of 18 patients (44.4 %) in Group A had an ER lag sign, compared to 5 of 8 patients (62.5%) in Group B, but this was not statistically significant (p=0.672). Significant post-operative improvements in SANE score were found in both groups (Figure 1) with no differences between groups. Pre-operative ER strength of the affected arm was significantly different in Group A (3.9kg) versus (Group B (0.58kg; p=0.011; Figure 1). However, ER strength was similar post-operatively (p=0.587; Figure 2). 0.05. In our study patients with any degree of TM fatty infiltration benefited from LTTT and experienced improvement in outcomes. Patients with moderate to severe TM fatty infiltration (Group B) had lower baseline ER strength, but this difference was no longer evident post-operatively. Although overall patient numbers in this study are small given the rarity of this condition and procedure, these outcomes suggest LTTT provides significant benefit to patients independent of TM fatty infiltration. This is in contrast to the LDTT, which is less successful in patients with moderate to severe TM fatty infiltration. Therefore, LTTT is a suitable salvage procedure for any degree of TM fatty infiltration, and should be strongly considered as an alternate procedure to LDTT in patients with high grade TM fatty infiltration. For any figures or tables, please contact the authors directly.