Teres minor denervation and pathologies resulting in shoulder joint instability and rotator cuff tears: A retrospective cross-sectional MRI study

Abstract

Teres minor denervation (TMD) has gained increasing attention in recent years, particularly with the advent of magnetic resonance imaging (MRI). The potential association between TMD and shoulder instability or rotator cuff tear remains a subject of interest in the orthopedic community. In this retrospective and cross-sectional study, authors aim to investigate the potential association between TMD and shoulder instability or rotator cuff tears. Authors retrospectively analyzed MRI findings from 105 patients with TMD, focusing on rotator cuff pathologies, posterior labrocapsular complex (PLCC) tears, and posteroinferior glenohumeral joint capsule alterations. Authors assessed the association between TMD and rotator cuff and PLCC tears. For the multivariate analysis, partial proportional odds models were constructed for subscapularis (SSC) and SSP tears. Rotator cuff tears were present in 82.9% of subjects, with subscapularis (SSC) tears being the most frequent (77.1%). A significant association was observed between TMD and rotator cuff pathology (P = .002). PLCC tears were found in 82.3% of patients, and humeral position relative to the osseous glenoid was noted in 60% of patients with TMD. A significant association was identified between TMD and shoulder instability or labral/capsular abnormalities (P < .001). More than half of the cases exhibited a long tethering appearance toward the axillary neurovascular bundle on T1-weighted sagittal images. Our findings suggest that TMD is significantly associated with rotator cuff tears and shoulder instability. This study highlights the importance of identifying and treating PLCC tears in patients with TMD to address shoulder instability. Further research is needed to elucidate the role of TMD in the pathogenesis of shoulder instability and rotator cuff pathology.

Figure 1.

Flow chart of study participant selection and inclusion process.

Figure 2.

A. A fat-saturated T2-weighted (FST2W) oblique coronal image of a 28-year-old male patient experiencing vague posterior shoulder pain for years illustrates joint capsule thickening. The two yellow scout lines represent the range of sagittal images obtained, with the green line indicating the location of the sagittal image shown in B. B. A T1-weighted (T1W) oblique sagittal image displays a redundant posteroinferior joint capsule. C. The same oblique coronal FST2W, with the green line shifted 3.3 mm medially, is presented to demonstrate that the two T1W oblique sagittal images in B and D are consecutive. D. A T1WI oblique sagittal image taken 3.3 mm medial to Figure B demonstrates the protrusion of the joint capsule and the obliteration of the fat plane between the capsule and the axillary nerve, potentially indicative of a fibrous band associated with quadrilateral space syndrome.

Figure 3.

Preoperative and postoperative MRI images of a 42-year-old male patient with right shoulder vague pain. The patient’s shoulder pain began 5 years ago, and the pain aggravated 1 month ago with night pain. Physical examination reveals full passive ROM, positive abduction and external rotation provocation test, and tenderness over the quadrilateral space. The patient underwent arthroscopic labral repair, and the symptoms significantly improved by the 4-week follow-up visit. A. Preoperative fat-saturated T2-weighted (FST2W) oblique coronal image demonstrates denervation edema of the teres minor (short arrowheads) and a small subacromial-subdeltoid bursitis. B. Oblique sagittal T1-weighted image (T1WI) reveals decreased volume of the teres minor and the posteroinferior joint capsule tethered (long arrowheads) to the axillary neurovascular bundle (short arrow). C. Preoperative T2-weighted (T2W) oblique coronal image displays denervation edema mixed with fatty infiltration. D. Preoperative FST2W axial image exhibits a posterior labrocapsular complex tear (long arrow). E. Arthroscopic image presents satisfactory labral repair. F. Postoperative T2-weighted oblique coronal image obtained 4 weeks after the arthroscopic surgery shows decreased high signal intensity of the teres minor compared to that of Figure C.

Figure 4.

A 62-year-old male patient presented with recent limited ability to move his right arm and has been experiencing poorly localized pain in the posterior shoulder region for decades. The patient underwent arthroscopic rotator cuff repair and subsequent rehabilitation. At a 30-month follow-up, the patient was symptom-free. A. On fat-saturated T2-weighted (FST2W) oblique coronal image, decreased volume of the teres minor is suspected with minimal denervation edema (arrowheads). B. Oblique sagittal T1WI shows severe atrophy of the teres minor (arrowhead). C. Axial FST2W image reveals an articular side partial-thickness tear of the subscapularis and mild medial subluxation of the long head of the biceps tendon (long arrow). D. On FST2W oblique coronal image, a full-thickness tear of the supraspinatus is observed. E. Arthroscopic image confirms the full-thickness tear of the supraspinatus. F. Satisfactory arthroscopic rotator cuff repair is performed.