Subacromial impingement syndrome – causes, symptoms, diagnosis, and treatment

Subacromial impingement syndrome (also known as subacromial syndrome or subacromial tightness) is a painful condition of the shoulder area in which there may be compression or restriction of space between the structures of the shoulder (e.g., the head of the humerus) and other elements surrounding the head of the humerus (e.g., the acromion and coracohumeral ligament).

It manifests itself as pain when raising the arm or performing abduction (i.e., moving the arm away from the body).

During these movements, irritation or damage to the periarticular structures (e.g., rotator cuff tendons) and subacromial space may occur.

There are several classifications of subacromial impingement syndrome, one of which is Neer’s classification, which describes 3 types of this condition:

• Type I, or mild subacromial impingement syndrome, involves reversible changes such as inflammation of the subacromial bursa and rotator cuff tendons. The main symptoms at this stage are swelling and pain during movement and after cessation of activity.
• Type II is an advanced stage of subacromial impingement syndrome – which is already associated with tendon fibrosis and degenerative changes in the subacromial bursa. The patient feels much more pain than in the mild stage of the condition.
• Type III is subacromial impingement syndrome associated with damage to the tendon structures of the rotator cuff. This is an advanced stage of the disease, caused by a lack of earlier treatment of subacromial impingement syndrome. The patient experiences significant limitation of mobility. Partial shoulder instability also occurs, and sometimes damage to the subacromial structures is also observed. At this stage, surgical treatment is recommended.

The potential causes of subacromial impingement syndrome can be divided into primary and secondary causes.

Primary (i.e., structural/anatomical) causes include:

• bone spurs (osteophytes) – forming in the area of the acromioclavicular joint,
• thickening of the coracoclavicular ligament,
• calcifications and degenerative changes around the shoulder joint,
• the shape of the acromion, which may cause compression.

Secondary causes (i.e., acquired/related to everyday use of the joint or specific movement patterns) include:

• weakness of the rotator cuff muscles, leading to instability in the joint,
• scapular movement disorder – which changes the mechanics of the joint,
• excessive instability of the shoulder joint – occurring, for example, in athletes,
• performing repetitive overhead movements – e.g., by swimmers, painters, hairdressers.

Among those most at risk of developing this condition are:

• athletes – conditions are particularly common in sports that involve moving the arms above the head (e.g., swimming, volleyball, tennis);
• manual workers – especially those who work with their arms raised above their heads (e.g., painters, construction workers, hairdressers);
• mature and elderly people – in people over 50-60 years of age, the elasticity of soft tissues decreases, degeneration of the rotator cuff tendons occurs, and bone spurs appear, which contributes to the condition;
• people with posture disorders and muscle weakness – incorrect joint alignment can lead to compression of structures in the shoulder area.

Young people under the age of 25 most often experience mild subacromial impingement syndrome. The more advanced stage most often affects patients in the 25-45 age group. People over the age of 50 most often struggle with the most severe form of subacromial impingement.

The most common symptoms of subacromial impingement syndrome reported by patients are:

• shoulder pain – especially when raising the arm, abducting it, or lying on the shoulder;
• limited range of motion, weakness in arm movements (e.g., abduction and external rotation);
• pain in the lateral part of the shoulder radiating toward the arm.

A physical therapist and physician conduct an interview and physical examination to:

• locate the pain,
• learn about the circumstances surrounding the onset of pain,
• assess limitations in mobility and strength.

The physical therapist assesses the patient’s ability to perform daily physical activities and conducts a series of tests to help locate the possible source of pain. The specialist may use ultrasound results and recommend that the patient see a doctor for further diagnosis.

The doctor may expand the diagnosis by ordering additional imaging tests:

• Shoulder ultrasound – useful for assessing the rotator cuff, bursa, and the presence of fluid or inflammation;
• Shoulder X-ray – to assess the shape of the acromion, the presence of osteophytes, calcifications, or subacromial space narrowing;
• Magnetic resonance imaging – the most accurate test for seeing damage to tendons and bursae.

Subacromial impingement syndrome is not the only cause of potential shoulder pain. That is why proper diagnosis and a broad perspective are so important when assessing shoulder joint pain. Differential diagnosis includes other causes of pain in this part of the body, including:

• bursitis,
• tendinopathy of the long head of the biceps tendon,
• arthrosis of the acromioclavicular joint,
• instability of the shoulder joint,
• synovitis,
• trigger points, e.g., of the trapezius muscle.

The first-line treatment is physical therapy. Patients often visit a physical therapist as their first point of contact, who, during the physical therapy examination, decides on the treatment or refers the patient for further medical consultation and additional diagnostics.

The main elements of therapy are:

• rest and avoidance of movements that provoke pain (e.g., working with raised arms);
• pharmacotherapy in the case of confirmed inflammation (corticosteroid injections if indicated);
• physiotherapy and rehabilitation, including:
  • exercises to strengthen the rotator cuff and muscles stabilizing the shoulder blade;
  • postural training (focusing on the postural muscles that maintain an upright posture);
  • stretching techniques, mobilization (improving mobility), and proprioception (sense of body position);
  • manual therapy.

Kinesitherapy, or movement therapy, is one of the most important tools for restoring fitness and relieving pain. It is also important to educate patients, explaining and showing them how to counteract ailments by changing their movement habits in everyday life.

The selection of exercises for subacromial impingement syndrome depends on the location of the pain and the diagnosis, which will indicate the causes of the symptoms. In the case of inflammation, rest is recommended, and in the case of degenerative changes in the subacromial structures, the patient’s previous experience with exercise and training, as well as their mobility and expectations, are important. The selection of exercises and their parameters should be supervised by a physical therapist.

Physiotherapy and rehabilitation are effective forms of treatment for subacromial impingement syndrome. Most patients experience improvement without the need for surgery. However, if there is no improvement after 3-6 months of conservative treatment, surgery should be considered. The most commonly used procedures are:

• arthroscopic subacromial decompression – removal of bone fragments or thickened tissue that compresses the tendons;
• acromioplasty – smoothing of the lower surface of the acromion;
• rotator cuff repair – repair of damaged tendons.

If the patient undergoes surgery, postoperative rehabilitation remains extremely important, including:

• early mobilization of the shoulder;
• gradual and controlled restoration of range of motion;
• strengthening and proprioceptive exercises;
• return to full activity after 3-6 months.

It is worth starting work with an experienced physiotherapist not only after surgery, but also before the planned procedure. This will be an important element of prehabilitation, i.e., preparing the body for the best possible surgical procedure and supporting subsequent recovery. At NAMI Medical Resort and Clinic, we take a comprehensive approach to helping patients before and after surgery. We use not only targeted physiotherapy treatments, but also, among other things, a carefully selected diet and stress reduction techniques.

The overall prognosis is good. It is improved by early detection of the cause and the initiation of targeted treatment and rehabilitation at the initial stage of the condition.

Most patients regain full shoulder function, and pain and mobility limitations usually disappear after several weeks of rehabilitation. Surgery is only performed on patients with chronic or advanced changes.

The duration of treatment depends on factors such as the extent of damage to the rotator cuff, avoiding shoulder overload, and following the physiotherapist’s recommendations.

Subacromial impingement does not have to be a recurring problem. It is important to maintain strength, flexibility, and proper shoulder mechanics.

Recommended preventive measures include:

1. Strengthening the rotator cuff and shoulder blade muscles;
2. Posture exercises;
3. Avoiding overexertion – including proper warm-up before exercise;
4. Stretching and mobility – training in full ranges of motion.

At NAMI, we operate in accordance with the spirit of holistic medicine. We take comprehensive care of our patients’ health. We not only provide individual physiotherapy, but also offer a nutritious diet and stress reduction classes.

We treat troublesome ailments, but our medical orthopedic program is designed to prevent recurrence and teach patients how to take care of themselves for a long, healthy, and balanced life. We provide post-operative rehabilitation and also work with patients before surgery to prepare their bodies to better tolerate invasive treatment.

NAMI Medical Resort and Clinic exclusively offers medical programs.

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