Impingement syndrome or Subacromial syndrome

Impingement or subacromial syndrome (SAS) is a pain syndrome in which the supraspinatus tendon is compressed when the arm is raised (elevated) and returned to the resting position.

Impingement affects athletes, housewives or people who work with their arms raised : volleyball players, throwers, swimmers, house painters, etc.
Periarthritis used to be used to name this condition, but this collective term also includes other diseases such as an inflammation of the bursa (bursitis) or similar.

Tendon pinching is not solely due to the proximity of the humerus and acromion, as there are other causes that can narrow the subacromial space: tendon and tendonitis, shoulder instability, bursitis, and the formation of bony prominences (osteophytes ) .

In the case of tendinitis, thickening of the tendon can be observed, which is caused by functional overload and entails the effusion of inflammatory fluid. Shoulder
instability is caused by:

  • weakness of the rotator cuff (muscle-tendon cap) that is unable to hold the head of the humerus (head of the humerus) and the socket of the shoulder together;
  • stretching of the shoulder ligaments.

Under these circumstances, when the arm is raised, the epiphysis of the arm bone shifts to the acromion. Subacromial bursitis is the inflammation of the subacromial bursa between the acromion and the head of the humerus; thickening of this structure creates abnormal pressure on the rotator cuff tendons. The osteophytes are calcium deposits on the bone that can protrude into the joint and thus disrupt its movement dynamics.

Depending on the intensity, impingement can be divided into 3 or 4 stages, depending on how far the disease has progressed.
In the first stage there is only acute inflammation of the bursa or tendons of the rotator cuff, with limitation of movements.
In the second stage, there is  degeneration of the tendon  with possible partial lesions, accompanied by effusion of inflammatory fluid or blood. This stage is very painful and the functionality of the shoulder is limited.

In the last phase there is a  complete rupture of the rotator cuff , the upper bone muscle (supraspinatus) is always mainly affected; plus effusion and unbearable pain even during breaks.
Tearing (rupture) of the tendon of a rotator cuff muscle causes a process of retraction and removal, as well as atrophy and degeneration of the muscle.


What are the causes of impingement syndrome?

Patients suffering from impingement syndrome often present with a hooked or downward- curved acromion ; this reduces the subacromial space through which the supraspinatus tendon runs. Shoulder tendinopathy may be due to the following reasons:

  • traumatic causes;
  • due to arthrosis;
  • in athletes who perform their throwing movement above shoulder joint height.

Another cause can be the job , because any activity in which the arm is raised more than 85°/90° in relation to the trunk can cause tendonitis, eg when painting. Tendovaginitis (tendosynovitis)  is inflammation of the tendon and the tendon sheath that surrounds it; in fact, the majority of tendons run within a sliding channel that reduces friction and prevents inflammation and degeneration.

What are the symptoms of impingement syndrome?

Commonly, rotator cuff disorders result in localized swelling and stiffness in the front of the shoulder. Painful stitches when lifting the arm can also occur.
Symptoms are also felt when the arm is lowered.
At first, the discomfort may be minor.
Most patients do not seek treatment in the early stages.

The following symptoms can occur:

  • Discomfort during movement, but also during the rest phase.
  • The pain may radiate to the front of the shoulder and down the outside of the arm.
  • Sudden pain when lifting objects and performing certain movements.
  • Athletes experience stabbing pains when making overhead movements to execute a throw or tennis serve.

As the disease progresses, the symptoms worsen and can include the following symptoms:

  • night pain,
  • loss of strength and movement,
  • Difficulty doing activities that involve putting your arm behind your back, such as tying up a bra.

If the pain starts suddenly, there may be a severe shoulder restriction. Any movement can be limited and painful.

If the impingement is based on subacromial bursitis , the symptoms mainly appear after a period of rest.
With a pause in movement of more than 15 minutes, the bursa thickens because it has no opportunity to distribute the excess synovial fluid in the joint ; when moving, on the other hand, it manages to deflate and thus no longer presses on the surrounding structures.
If the impingement is the result of chronic tendinitis , the pain will be felt when the arm is raised above shoulder height and with internal and external rotation. In worse cases, the patient also feels pain during pauses in movement.
Some patients do not know how to sleep, they toss and turn in bed all night looking for a pain-free position because in some cases both shoulders are affected; so these people are tired and nervous during the day.
The limitation of motion may occur in the last segment of the joint’s arc of motion, but tendinitis causes discomfort midway through the movement.
Once a certain degree of stiffness is felt, disuse of the shoulder leads to  muscle and tendon wasting (atrophy) and adherences that worsen the clinical picture.

How is impingement syndrome diagnosed?

For the diagnosis of impingement syndrome, the doctor must conduct a clinical examination and perform various tests: Neer, Yocum, Jerk, Jobe, etc.
Then he will examine the medical history and evaluate the strength and flexibility of the shoulder.
The specialist, orthopedist or physiatrist, will decide whether magnetic resonance imaging or sonography should be performed to assess the condition of the tendons and bursa.

Commonly, young athletes with shoulder pain suffer from tendonitis or instability due to a dislocation, while older people have at least one rotator cuff tendon completely torn due to a fall or a sudden movement (such as grasping a falling object).

Ultrasound of the painful shoulder may show minimal inflammation or tendonitis; when compared to the healthy shoulder, it could be seen that there are multiple sites of inflammation, degeneration of tendon structures, and calcifications.
This means that the non-painful shoulder is actually worse off than the one with pain. This is possible because pain and inflammation do not always correspond.
We can have practically 10 degenerated tendons with effusion and no pain.
Imaging diagnostics are necessary to rule out other serious diseases, such as those of an oncological nature, but they are not the only diagnostic option.

What can you do? Which therapy is suitable for impingement syndrome?

Treatment of a sore shoulder suffering from bursitis or acute tendonitis begins with physical therapy to reduce the intensity of the pain: Tecar-Therapy ®,  CO2 laser  or ultrasound. Once the patient is able to perform exercise exercises , toning is begun by strengthening the extrarotator (rotator cuff) and retropulsor (rhomboidal, large rounded, and large dorsi) muscles to correct the imbalance between the anterior and posterior deltoid muscles.

The  manual therapies are helpful to:

  • align the joint correctly;
  • release the contractures affecting shoulder dynamics;
  • Remove connective tissue adherences.

Myofascial manipulation is a very effective form of therapy for the manual treatment of shoulder periarthritis.
In the case of chronic inflammation that is resistant to conservative treatment methods, the specialist may recommend three local cortisone infiltrations after a few months . Younger people may consider reconstructive surgery for a complete tendon lesion; Elderly people, on the other hand, are rarely recommended for surgery because there are other muscles performing the same jobs as the torn muscle.

You can carry out all day-to-day activities. Calcium deposits cannot be removed with physical therapy, not even with shock waves , only a surgeon can remove them surgically. The goal of physical therapy is to relieve pain, even where calcium deposits are present, and to restore full range of motion when limited.

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