The shoulder is a marvel of human anatomy, offering an impressive range of motion. However, this mobility comes at a cost, as the shoulder joint is highly susceptible to various conditions and injuries, one of the most common being impingement syndrome. In this  article, I will discuss the causes, symptoms, diagnosis, and treatment options for shoulder impingement syndrome, with a primary focus on rehabilitation techniques to help individuals recover and regain full shoulder functionality.

Introduction to Shoulder Impingement Syndrome

Shoulder impingement syndrome is a painful and often debilitating condition that occurs when the tendons of the rotator cuff and the subacromial bursa become pinched or impinged between the bones of the shoulder, primarily the acromion (a part of the scapula or shoulder blade) and the humerus (the upper arm bone). This impingement leads to inflammation, pain, and restricted shoulder movement.

Anatomy of the Shoulder

Before delving into the causes and rehabilitation of shoulder impingement syndrome, it’s crucial to understand the intricate anatomy of the shoulder joint. The shoulder comprises three bones: the humerus, the clavicle (collarbone), and the scapula (shoulder blade). The glenohumeral joint, where the head of the humerus articulates with the shallow socket of the scapula, allows for the remarkable range of motion in the shoulder.

Rotator Cuff and Subacromial Bursa – The rotator cuff is a group of four tendons and muscles that stabilize the shoulder joint and facilitate its movement. These four muscles include the supraspinatus, infraspinatus, teres minor, and subscapularis. They work in unison to control arm movements and maintain joint integrity. The subacromial bursa is a fluid-filled sac that reduces friction between the rotator cuff tendons and the acromion, promoting smooth shoulder motion.

Causes of Shoulder Impingement Syndrome

Understanding the underlying causes of shoulder impingement syndrome is crucial for effective rehabilitation. Several factors contribute to the development of this condition.

Anatomical Factors

Shape of the Acromion

The shape of the acromion can vary from person to person. Some individuals have a flat or curved acromion, while others have a hooked or pointed acromion. A hooked acromion is more likely to impinge on the underlying tendons, increasing the risk of impingement syndrome.

Bone Spurs

Over time, the formation of bone spurs (osteophytes) on the acromion or the clavicle can reduce the space within the subacromial space, making impingement more likely.

Overuse and Repetitive Movements

Overhead Activities

Engaging in repetitive overhead activities, such as painting, swimming, or throwing, can lead to overuse of the shoulder joint. This overuse can irritate and inflame the rotator cuff tendons, increasing the risk of impingement.

Poor Posture

Poor posture, especially slouching or forward-leaning positions, can alter the biomechanics of the shoulder joint, narrowing the subacromial space and leading to impingement over time.

Muscle Imbalances

Muscle imbalances in the shoulder girdle can also contribute to impingement syndrome. Weakness or tightness in certain muscles can alter the mechanics of the shoulder joint, leading to impingement.

Trauma and Injuries

Shoulder injuries, such as falls or accidents, can damage the structures within the shoulder joint, leading to inflammation and impingement syndrome. Additionally, dislocated shoulders or fractures can alter the joint’s anatomy, increasing the risk of impingement.

Signs and Symptoms of Shoulder Impingement Syndrome

Recognizing the signs and symptoms of shoulder impingement syndrome is essential for early diagnosis and prompt treatment. Common symptoms include:

Pain

Pain is the hallmark symptom of shoulder impingement syndrome. The pain is typically located at the front or side of the shoulder and may radiate down the arm. It is often aggravated by overhead movements or reaching behind the back.

Weakness

Individuals with impingement syndrome often experience weakness in the affected shoulder. This weakness can affect the ability to lift objects or perform daily activities.

Limited Range of Motion

Impingement syndrome can restrict shoulder mobility. Individuals may find it challenging to raise their arms overhead or reach behind their back.

Night Pain

Many people with shoulder impingement syndrome report pain at night, particularly when lying on the affected shoulder. This can disrupt sleep and lead to chronic fatigue.

Clicking or Popping

Some individuals may hear clicking or popping sounds when moving their shoulder. These noises can indicate underlying structural issues.

Diagnosis of Shoulder Impingement Syndrome

Diagnosing shoulder impingement syndrome involves a combination of clinical evaluation, patient history, and imaging studies. Healthcare providers typically follow these steps:

Medical History

The doctor will ask about the patient’s symptoms, including when the pain started, its location and severity, and any exacerbating factors like specific movements or activities.  Oftentimes, impingement syndrome can gradually appear with no obvious cause, but if you look at the long term history of the patient’s work and/or recreational activities, aggressive shoulder movements are typically included (repetitive lifting above the shoulder; contact sports, tennis, baseball pitcher, etc.).

Physical Examination

During a physical examination, the healthcare provider will assess the range of motion in the affected shoulder, strength, and any signs of inflammation or tenderness.  The cardinal sign is pain with shoulder abduction (raising the arm from the side causes a deep, sharp pain inside the shoulder joint; patient has difficulty raising his/her arm above shoulder level due to mechanical restriction and acute pain.

Imaging Studies

Imaging studies, such as X-rays, ultrasound, or MRI, may be ordered to visualize the structures within the shoulder joint. X-rays can reveal bone abnormalities, while ultrasound and MRI can provide detailed images of soft tissues like tendons and the subacromial bursa.  However, this is usually only done if rest, physical therapy, and home care do not produce desired results after a week.

Cortisone injection

In some cases, an injection of a local anesthetic into the subacromial space may be performed. If the pain is alleviated shortly after the injection, it can confirm the diagnosis of impingement syndrome.  This is because with impingement syndrome, there is swelling and inflammation, and cortisone is a quick-acting anti-inflammatory medication.  So, if the pain is alleviated following a cortisone shot, it confirms there is localized swelling, which is likely coming from either the bursae or a tendon.

Non-Surgical Rehabilitation for Shoulder Impingement Syndrome

The treatment of shoulder impingement syndrome typically begins with non-surgical interventions, such as physical therapy and lifestyle modifications. The goals of rehabilitation are to alleviate pain, improve shoulder function, and prevent recurrence.

Rest and Activity Modification

Resting the affected shoulder and avoiding activities that worsen symptoms are essential in the early stages of rehabilitation. This may include temporarily ceasing activities that involve repetitive overhead motions.

Physical Therapy

Physical therapy is a cornerstone of non-surgical treatment for shoulder impingement syndrome. A qualified physical therapist will design a personalized exercise program to address muscle imbalances, improve strength, and enhance shoulder mobility. Common physical therapy techniques include:

Stretching Exercises

Stretching exercises target tight muscles in the shoulder girdle and surrounding areas. This can help improve flexibility and reduce tension that contributes to impingement (see video below).

Modalities

You can use a red light therapy wrap to reduce pain and swelling of your impingement syndrome.  Red light therapy wraps use light in the therapeutic wavelengths of red and infrared to accelerate tissue healing and deep heat tissues to increase blood flow and oxygen.  See below for an example:

SUMMARY:

Shoulder impingement syndrome occurs when a swollen tendon and/or bursa inside the glenohumeral joint, where your humerus articulates with your scapula, impedes movement of the joint by rubbing against hard structures, particularly the acromion.  The goal is to shrink the swollen tendon so that proper movement is restored, and then correct any biomechanical deficiencies in the shoulder complex, such as weak or tight muscles, and subluxated joints affecting the shoulder movements,  using exercise rehabilitation, joint mobilization and red light therapy.