Shoulder impingement is one of the most common ailments in athletes and non-athletes alike. It can be from an overuse repetitive injury or from a traumatic strain of the arm. The rotator cuff consists of four tendons that surround and grab the ball of the joint, called the humeral head, and function to move the arm in space. It also functions to stabilize the joint, pulling the humeral head down into the socket or the glenoid. Impingement simply means the cuff gets pinched between the humeral head and the bone above it, the acromion. Left untreated, this can progress to a rotator cuff tear. While a full thickness tear most often needs surgery, impingement most often does not. In fact, this surgery called arthroscopic subacromial decompression or acromioplasty is the most over-performed shoulder surgery in America.
Neer described impingement and the 3 types of acromion shapes. Type 1 is flat, type 2 curved and type 3 hooked. The latter two decrease the space available for the cuff, increasing the risk of impingement. The acromion can also have lateral down sloping, and can develop bone spurs primarily anterior and laterally due to rubbing overtime. These can further decrease the supraspinatus outlet narrowing the space available for the rotator cuff. If the cuff gets pinched, it becomes inflamed. An inflamed cuff is not only tender and easier to pinch, but is also weaker. A weaker cuff allows the humeral head to rise up and come in closer contact to the acromion. Additionally, the joint becomes more unstable which causes the cuff to work harder to stabilize the joint, which in turn causes more inflammation and thus the problem will continuously cycle until either the cuff tears completely or proper treatment stops the process.
The most common complaints of impingement include pain with reaching, lifting and lying on the shoulder at night. There are special tests to diagnose impingement on examination including Neer sign, Hawkins Sign, painful arc and Neer impingement test. The latter is an injection of lidocaine, a numbing agent, into the subscapular space (the space above the cuff and below the acromion) to see if the pain goes away. Kibler more recently described the retracted scapular test which the examiner forces the scapula, or shoulder blade, backwards, and has the patient actively raise the arm forward. Improved strength and motion and/or decreased pain are also signs of impingement.
I have developed a similar test which is a variation of this concept, and have been using it for the past several years called the Noy Scapular Tilt Test. The difference with this test is that it helps predict whether surgery will be necessary. The patient actively retracts the scapula by asking them to stick their chest out, with the arms dangling loose at the sides. The examiner then passively raises the arm up. If the Neer sign was positive, and pain is eliminated during this test, it is a positive Noy Scapular Tilt Test. The implication of a positive test is it predicts that surgery will probably not be necessary and should not be the primary option. Instead, a good scapular strengthening program, which is part of my “No Pain Principle Shoulder Rehab Program” will more than likely be successful in treating the impingement. This includes painless cuff strengthening, scapular stabilization, posterior capsular stretching and icing after exercising.
If necessary, a cortisone injection into the subacromial space can help temporarily reduce the inflammation allowing the ability to increase the intensity of the rehabilitative program. The exercises are often done under the guidance of a physical therapist, but can be done at the gym by knowledgeable motivated patients.
Patients who have similar or worse pain on the Noy test compared to the Neer sign are more likely to require surgery to open the space available for the cuff by removing some of the acromion and/or bone spurs. In my experience, this is less common.
In conclusion, arthroscopic surgery for impingement is usually not necessary and overdone in the United States. A positive Noy Scapular Tilt Test can predict that a patient does not need surgery, and following the principles of the “No Pain Principle Shoulder Rehab Program” will usually be successful in eliminating symptoms.
Ron Noy, MD
Prestige Orthopaedics & Sports Medicine
424 Madison Avenue at 49th Street, 9th Floor, New York, NY 10017