CORR Insights®: What is the Best Clinical Test for Assessment of the Teres Minor in Massive Rotator Cuff Tears?

Abstract

A s the authors of the current study eloquently state, ‘‘The teres minor seems to be a forgotten muscle in the evaluation and management of rotator cuff disorders.’’ This statement is especially true in the setting of massive rotator cuff tears. However, recent research has allowed us to gain an understanding of the importance of the teres minor as it relates to clinical and functional outcomes in massive cuff tears. Simovitch et al. [5] demonstrated that a functional teres minor with less fatty infiltration (Grade 0, 1, or 2) resulted in an improved Constant score and better external rotation after reverse shoulder arthroplasty. Further, a recent study [4] found that the teres minor will hypertrophy when there is an infraspinatus tear, suggesting an overlap of function and the potential to gain function for external rotation even in patients with large posterosuperior rotator cuff tears. The current study focuses on our ability as clinicians to detect the function of the teres minor in massive rotator cuff tears, and determine the role the teres minor has in clinical outcomes. With the data presented, it appears that external rotation lag sign is an excellent test for teres minor dysfunction and can be used to predict teres minor dysfunction and clinical outcomes after reverse shoulder arthroplasty. This is important in educating the patient in the expected post-operative function after reverse shoulder arthroplasty.