Relation between Hypertrophy of Teres Minor Muscle and External Rotation Lag Sign in Patients with Rotator Cuff Pathology.

Abstract

Background:The purpose of this study was to determine the compensatory hypertrophy of the teres minor (TM) muscle in rotator cuff tears (RCTs) and also the relation between hypertrophy of TM muscle and external rotation lag sign (ERLS).Methods:In the period between June 2017 and April 2018, forty patients with RCTs of the shoulder joint came to our institution. We determined the ERLS of all the RCT patients along with the TM occupation ratio in the magnetic resonance imaging (MRI) scan and correlated them together. The normal mean of TM occupational ratio was calculated from ten patients who have undergone MRI scan for other causes but with normal rotator cuff muscles.Results:In our study, the mean TM occupational ratio of 10 normal rotator cuff patients was 0.277. Of 40 rotator cuff pathology patients, the mean occupational ratio of the TM in RCTs is 0.359. Sixteen of the 40 patients had ER lag positive and the remaining 24 patients had ER lag negative. Those who were ER lag negative have an TM occupational ratio >0.401. A positive correlation was found between hypertrophy of TM and ERLS.Conclusion:ERLS will be negative in patients with hypertrophy of TM in the setting of posterosuperior cuff tears. There is a strong correlation between cuff tears and hypertrophy of TM muscle, which helps in better prognosis and functional outcome of the patients treated with surgical intervention.