What is Shoulder Impingement?
Also known s “Swimmer’s Shoulder”, the term “Impingement Syndrome” is used to describe a process in which the tendons of the rotator cuff become pinched (or “impinged”) upon themselves or the bony prominences of the shoulder. This commonly occurs as a result of repetitive overhead sporting activities such as throwing, swimming, tennis, weight-lifting, volleyball, etc. It may also occur after a day of changing light bulbs around the house or painting a building. Early on, the tendons and/or overlying bursae may be simply irritated or inflamed. However, over time, the impingement may slowly wear a hole through the rotator cuff resulting in the more worrisome rotator cuff tear.
What Types of Shoulder Impingement are There?
Impingement syndrome is the most common overuse shoulder problem we see in our clinic. It is generally broken down into two basic categories: “Primary” and “Secondary” impingement.
“Primary impingement syndrome” describes a process in which pain in the shoulder is caused by direct (or primary) mechanical rubbing of the rotator cuff tendon by surrounding bony structures. This contact occurs when the arm is in an overhead position and generally relieved while the arm is at the side. This type of impingement is more common in athletes and individuals over 30 years of age.
“Secondary impingement syndrome” (a.k.a. “Internal impingement”) is the most common form of impingement in athletes under 30 years of age. It often presents with similar or even identical complaints as primary impingement syndrome (and also frequently involves an irritation of the rotator cuff). Secondary impingement, however, is not caused by direct mechanical irritation of the rotator cuff against the bone, but rather due to “pinching” of the rotator cuff in the shoulder joint itself and/or overuse of the rotator cuff from attempting to stabilize an unstable (or “loose”) shoulder. This is a task the rotator cuff was not specifically designed to do and is, thus, a result (“secondarily”) of the underlying shoulder instability or looseness. Sometimes shoulder looseness occurs due to an isolated traumatic event causing the shoulder to dislocate (pop out of joint completely) or sublux (partially come out of joint). In other cases, through repetitive stretching of the shoulder ligaments or capsule, the ligaments become stretched over time allowing the shoulder to become loose. And lastly, many others simply have naturally (genetic) relaxed ligaments allowing for increased joint looseness. An extreme example would be a contortionist.
What Does Shoulder Impingement Feel Like?
Shoulder impingement symptoms can vary widely and may present simply as persistent or recurrent pain with using the arm overhead. The location of pain is usually non-specific and may occur over the front, back, or down the side of the shoulder (or all of the above). As symptoms worsen and/or the rotator cuff becomes more inflamed or injured, the shoulder will often begin to bother at night and affect one’s sleep. Popping or catching may be present in some cases but this is not a common finding with uncomplicated impingement.
Do I Need X-Rays (Or MRI)?
The most effective way to diagnose impingement is through a detailed history and physical exam by a well-trained, experienced Sports Medicine specialist. X-rays will often be obtained to rule out other causes of shoulder pain (arthritis, calcific tendinitis, bone tumors, etc) but alone are not diagnostic. Ultrasound may commonly be used at the time of your initial visit to hopefully confirm that the rotator cuff has not yet been injured and/or to look for the presence of significant bursitis or other unexpected abnormality. The option of obtaining an MRI may be discussed if other concerns arise during your visit, but this is usually not considered helpful prior to an adequate trial of conservative treatment.
Does Physical Therapy Help?
It is our experience that the vast majority of primary impingement syndromes will improve with an exercise program focused on strengthening the rotator cuff muscles. Some of the exercises you will be shown are designed to work the individual rotator cuff muscles in a way that avoids pinching against the bony prominences. By strengthening these muscles, they no longer become fatigued as quickly, thereby preventing the ongoing impingement of the rotator cuff described earlier.
Secondary impingement syndrome is often a more difficult condition to treat. Depending on which direction the shoulder is loose, exercise and rehabilitation have variable success. We feel that a trial period of rehabilitation is critical for all impingement patients. A significant percentage of people with secondary impingement may return to previous activities pain-free with shoulder strengthening and rehabilitation. For those patients who fail focused conservative rehabilitative treatment, cessation of activities that tend to produce excessive shoulder motion may be required. For many people, stopping or modifying the aggravating overhead activity can quickly eliminate symptoms. Unfortunately, for many athletes the “aggravating overhead activity” may be the sport they love.
If Surgery is Required, What Does That Look Like?
For some people, modification of activities and focused therapeutic exercises may ultimately fail. For primary impingement, this is often due to an anatomic abnormality of the acromion (bone). Some people have a curvature (“hook” or “spur”) of the acromion, which projects down toward (or into) the rotator cuff, narrowing the space between the cuff tendons and the undersurface of the bone. This surgery is an arthroscopic, outpatient surgical procedure to burr down the “hook” of the acromion, allowing for greater clearance of the rotator cuff under the acromion and eliminating the impingement symptoms. Return to overhead sporting activities may be as soon as 4-6 weeks, though more aggressive, repeated use (tennis, throwing, etc.) may require up to 2-3 months.
For secondary impingement, surgery can have good to excellent results depending on the direction of shoulder looseness. The goal of this arthroscopic, outpatient surgery is to tighten up the ligaments or joint capsule of the shoulder to prevent the shoulder from sliding in and out of the socket. This “tightens up” the shoulder so the rotator cuff no longer has to “work overtime” to help stabilize the shoulder.
The above diagnoses are the most frequent causes of persistent shoulder discomfort in the active individual. Because shoulder impingement can frequently overlap with more significant shoulder problems, an accurate diagnosis is essential. This may require one or two repeat examinations, a trial of conservative rehabilitative exercises, and/or an occasional injection of local anesthetic in an attempt to isolate the painful portion of the anatomy. X-rays, ultrasound, and even MRI scans are often helpful depending on exam findings and one’s individual needs.
To set up an appointment for further evaluation, please call (208) 336-8250.