Subscapularis Tendon Tears
What is it?
It is the largest & strongest cuff muscle, providing 53% of total cuff strength. The upper 60% of the insertion is tendinous and the lower 40% muscle. It is a passive restraint in neutral, but not abduction.
It's role is to turn the arm inwards and is a key muscle in doing any lifting movements across your chest or twisting inwards. It is essential for overhead sports, such as swimming, racquet sports and throwing.
Tears of the subscapularis tendon are less common than supraspinatus and infraspinatus tendon tears (commonly simply known as ' rotator cuff tears '). However, they can be much more painful, since the restraints to the long head of biceps tendon are often also torn and the biceps tendon dislocates from it's groove. The biceps tendon then also becomes painful and weak.
How is it diagnosed?
A person with a subscapularis tear will have pain at the front of the shoulder and weakness with activities that involve forward lifting, twising the arm inwards and sports. The clinician can detect the following on examination: increased pasive external rotation, weak internal rotation, positive tests for subscapularis tears ( Bear-hug test , belly-press test , Gerber's lift-off test ).
MRI Scans showing the subscapularis tear and dislocated Long Head of Biceps tendon:
How is it treated?
Low demand and elderly patients can be well managed with physiotherapy rehabilitation.
In an active person, surgical repair is recommended. The surgery can be performed by arthroscopy or open surgery depending on the surgeon's expertise, tear pattern and patient. If the biceps is affected a biceps tenodesis is generally required also.
Some tears may be too old (chronic) and large for a direct repair. In these cases a Pec Major transfer operation can be performed.