Shoulder surgery to repair a rotator cuff tear is designed to reduce pain, restore power (strength), and improve motion. Patients report that pain relief is by far the most important and best result of this procedure. Is it possible to know before surgery how much improvement in pain might be expected?
According to orthopedic surgeons from Seoul, Korea, it is possible to predict pain reduction after rotator cuff repair. And they say this is the first study of its kind! How is it done? A simple injection of a numbing agent called lidocaine is inserted into the subacromial space.
The subacromial space is the area just above the head of the humerus (upper arm bone) and below the acromion. The acromion is a curved piece of bone that comes around from the back of the shoulder blade over the humeral head.
Muscles of the rotator cuff pass underneath this arch of bone. As the arm lifts up, the damaged (torn) or weak rotator cuff can get pinched between the head of the humerus and the acromion. This condition is called impingement. It’s the pinching of the tendon that causes pain and loss of motion and function.
Injecting a numbing agent into this space would provide substantial pain relief when impingement is the real problem. The authors called this test the modified impingement test. It’s modified because instead of just assessing pain while the arm is lifted, there’s been the injection of lidocaine as well.
The modified impingement test is simple, safe, and easy to do. It provides a fairly accurate estimate of how much pain relief patients can expect with rotator cuff repair surgery. It’s not a good predictor of how much change in motion or function might be expected from before to after surgery. But since pain is the primary symptom of concern, knowing pain will be relieved may be enough to satisfy patients and help them when making the decision to have surgery.