Rotator Cuff Injury

Excerpt

The shoulder joint classifies as a ball and socket joint; however, the joint sacrifices stability for mobility. The glenoid is a shallow rim, and one description is as looking like a golf ball on a tee or a basketball on a dinner plate. The rotator cuff consists of four muscles originating on the scapula and inserting on the superior humeral head to improve stability. The subscapularis inserts on the lesser tubercle of the humerus, and it functions as an internal rotator. The supraspinatus muscles insert onto the greater tubercle of the humerus with its function as an abductor for the initial 30 degrees of abduction. The infraspinatus also inserts onto the greater tubercle, but a little inferior to the supraspinatus, and it functions as an external rotator. The teres minor inserts inferior to the infraspinatus on the greater tuberosity, and it functions as an external rotator as well. Additionally, they all work as stabilizers of the glenohumeral joint.

Rotator cuff injury runs the full spectrum from injury to tendinopathy to partial tears, and finally complete tears. Age plays a significant role. Injuries ranged from 9.7% in those 20 years and younger increasing to 62% in patients 80 years and older (whether or not symptoms were present). Increasing age and those with unilateral pain are also at risk for a tear in the rotator cuff of the opposite shoulder. In a study comparing patients with unilateral shoulder pain, the average age for a patient having no cuff tear was 48.7 years. After age 66, there is a 50% likelihood of bilateral tears. Additionally, age was linked to the presence and type of tear but did not correlate with tear size.

Unfortunately, there is a lack of good evidence on the optimal treatment of tears in patients younger than 40. The tears tend to be more traumatic and likely respond to surgery better, but the role of non-surgical management needs to be better defined.