What is subacromial impingement?

Subacromial impingement is an intense pain in the shoulder that arises from the inflammation and compression of the bursa covering the rotator cuff tendons.

This pain often worsens at night, which can prevent a person from falling asleep and can negatively affect a patient’s quality of life.

It’s important to know that subacromial impingement is the most common cause of shoulder pain (half of all cases) and is due to a narrowing between the head of the humerus and a part of the scapula called the acromion. The rotator cuff tendons are located within this space, protected by a sac called the subacromial bursa, which allows them to glide. However, when there is friction and compression between the bone and the tendons, this sac thickens, causing pain and stiffness.

Subacromial impingement can occur due to:

• Deficiencies in collagen production
• Genetic conditions
• Weakened muscles
• Aging
• Chronic inflammation
• Excessive exertion
• Rotator cuff tear
• Calcific tendinitis
• Tendinosis

Symptoms of Subacromial Impingement

Subacromial impingement usually occurs in active people or those over 40 years old. Due to the repetitive friction of the rotator cuff tendons and the subacromial bursa, inflammation and pain are generated, and over time, it can lead to more serious tendon injuries such as tendinopathy or even a rotator cuff tear.

Subacromial impingement syndrome usually develops progressively and can be related to anatomical abnormalities such as a hooked acromion, muscle imbalances, or overuse of the shoulder.

Among the most common symptoms of subacromial impingement are:

• Sharp pain in the front and side of the shoulder
• Inflammation
• Pain radiating to the arm
• Limited range of motion
• Tight neck muscles
• Arm weakness

Diagnosing Subacromial Impingement

The diagnosis of subacromial impingement is based primarily on the patient’s medical history and a physical examination.

The doctor usually asks about the type and location of the pain, as well as the factors that can aggravate it—for example, lifting the arm—and the duration of the symptoms.

During the physical exam, specific tests may be used, such as the Neer test, the Hawkins-Kennedy test, or the Yocum test, which reproduce the characteristic pain by compressing structures under the acromial arch. All of these maneuvers help identify the presence of irritation or inflammation of the rotator cuff or the subacromial bursa.

Subsequently, to reach a confirmed diagnosis or evaluate the degree of involvement, various imaging studies can be used. A simple X-ray helps detect bone abnormalities such as the shape of the acromion or the presence of osteophytes.

An ultrasound is useful for visualizing tendinopathies or bursitis, while an MRI provides a more detailed image of soft tissues, which is useful for detecting partial or complete rotator cuff tears.

Sometimes, a diagnostic infiltration with a local anesthetic in the subacromial space may be requested. If the pain temporarily disappears after the injection, it is considered an important indication of subacromial impingement.

Treatment for Subacromial Impingement

Treatment for subacromial impingement usually begins with conservative measures, especially in the initial stages or in cases where there is no significant tendon tear. The goal of conservative treatment is to reduce inflammation, relieve pain, and restore shoulder function. This is achieved through relative rest, which means avoiding repetitive overhead movements, applying localized ice, using nonsteroidal anti-inflammatory drugs (NSAIDs), and targeted physical therapy.

If conservative treatment does not produce improvements after several weeks or months, other therapeutic options will be considered.

Subacromial injections help reduce inflammation and pain in resistant cases, although their use should be limited due to the risk of long-term adverse effects.

In patients who have an anatomically narrow acromion or persistent structural injuries, a surgical option may be indicated. The most common is arthroscopic acromioplasty. This arthroscopic surgery consists of resecting part of the acromion to increase the subacromial space and release the compressed structures.

At the Orthopedics and Traumatology Center at ABC Medical Center, we can provide you with specialized care. Contact us!