Narrow shoulder syndrome (impingement)

Impingement syndrome, also called shoulder tightness syndrome, refers to a pinching of tendons or other soft tissue structures under the acromion.

The entrapment(impingement) is only one part of a symptom complex, the subacromial pain syndrome (SAPS). Subacromial syndrome groups together several disorders of the subacromial space. This also includes tendinosis/tendinitis calcarea with calcium deposits in the tendons or bursitis (bursitis subacromialis).
The causes are poor posture or muscular imbalances. But certain anatomical conditions (changes in the shape of the acromion or bony attachments) can also lead to impingement. The resulting permanent mechanical irritation can lead to inflammatory irritation of the tendons running under the acromion and to inflammation of the bursa (bursitis). This occurs due to a narrowing of the space between the humeral head and the acromion, the subacromial space. Sliding of these structures under the acromion becomes difficult. As a result, movement restrictions and pain in the shoulder occur. In the long term, this can also lead to the formation of tears in the tendons.

The shoulder joint is a complex system consisting of bones, ligaments, bursae and tendons and is formed by the head of the humerus and the glenoid cavity, which is part of the scapula. Surrounding the shoulder joint is a capsule. Above this joint lies the acromion (roof of the shoulder). The head of the humerus is larger than average in relation to its socket, which leads to a large range of motion in the shoulder but also to a certain susceptibility to instability. This makes the shoulder joint predisposed to injury, such as shoulder dislocation.
The shoulder joint is stabilized by 4 muscles that together form what is known as the rotator cuff. The supraspinatus tendon runs right between the humeral head and the acromion, so this tendon is often affected in impingement syndrome. Furthermore, there is a bursa in the space between the humeral head and the acromion, which can also be affected by impingement.

Signs of impingement syndrome may include:

• Pain when lifting the arm to the side
• Pain with overhead movements
• Restriction of the mobility of the shoulder
• Pain with pressure on the shoulder joint
• Pain at night when lying on the affected shoulder

In impingement syndrome, pain is caused by the impingement of tendons, especially during certain movements of the arm. Lateral raising of the arm and overhead movements are in the foreground.

Depending on the duration and severity of the disease, there may be a pronounced restriction of movement.

In extreme cases, irritation and degeneration of the rotator cuff tendons can lead to a tear in this muscle group (rotator cuff lesion). In the case of the above-mentioned symptoms, careful clarification is therefore of great importance so that targeted therapy can be started early and further complications can be prevented.

Causes of impingement syndrome include:

• Overloading the shoulder
• Disturbed movement sequence due to incorrect posture/muscle imbalances
• Congenital anatomical peculiarities of the acromion
• Calcific shoulder (tendinitis calcarea)
• Tendonitis of the supraspinatus tendon, inflammation of the bursa (bursitis)

Impingement syndrome can be triggered by numerous factors. One of the main causes is overloading the shoulder. This is especially true for groups of people who perform a lot of overhead movements, such as painters or volleyball players.

Congenital structural features of the acromion can also be causative for impingement syndrome. For example, the acromion may be hook-shaped, leading to mechanical constriction of the supraspinatus tendon under the acromion.

In the context of calcareous shoulder (tendinitis calcarea), calcium deposits occur in the area of the supraspinatus tendon. These can cause both inflammation of the tendon (tendinitis) and inflammation of the bursa (bursitis), which in turn leads to tightness in the subacromial space.

In a personal consultation with our doctors, your exact complaints will be asked. This includes, among other things, the temporal course, the localization and the strength of the complaints.

Our doctors can then confirm the suspicion of shoulder impingement syndrome by means of a functional examination. Here, the so-called "painful arc" should be mentioned in particular: When lifting the arm sideways, pain occurs especially at an angle between 60 and 120°. The shoulder is also checked for all other mobility.

Imaging, e.g. in the form of an ultrasound examination, an X-ray or an MRI, provides further evidence of impingement. Here, ultrasound may show thickened bursae, suggesting an inflammatory process. X-ray may show narrowing of the subacromial space or the impingement-promoting anatomic shape of the acromion. MRI has the advantage of better visualization of the muscles and their tendons and early detection of inflammation or rupture of the tendons.

Conservative therapy

If a tear in the tendons (rotator cuff) can be ruled out, a conservative therapeutic approach is usually justified.

The following conservative therapies are available:

• Protecting the shoulder: avoid overhead movements
• Physical measures: Cold (cooling pads)
• Drug therapy: analgesics, injection of cortisone under the acromion, injection of platelet-rich plasma
• Physiotherapy: strengthening the muscles of the rotator cuff
• Shock wave treatment, e.g. in the case of a calcified shoulder

If you have been diagnosed with impingement syndrome, treatment should be started as early as possible. There are various therapeutic approaches. The choice of therapy depends on many factors, such as your age or the amount of sport you do in your daily life.

In most cases, satisfactory improvement can be achieved by means of conservative therapy. Patients should avoid pain-inducing movements, such as overhead work, as far as possible. Cooling pads can provide relief in acute pain.

Drugs from the group of non-steroidal anti-inflammatory drugs (NSAIDs) not only reduce pain, but also inhibit the inflammatory response. In cases of severe pain that cannot be adequately treated with these drugs, it is possible to inject cortisone under the acromion. For acute overuse and tendon damage, infiltration therapy with platelet-rich plasma may be helpful. In addition, our physicians may prescribe physical therapy as needed. The goal of physical therapy is to strengthen the rotator cuff muscles that stabilize the shoulder joint and thus increase the subacromial space.

If impingement syndrome is caused by calcified shoulder (tendinitis calcarea), shock wave therapy can be used for treatment. Ultrasound waves localized to the shoulder joint ensure that the calcium foci are removed more quickly.

Operation

If there is no improvement despite these conservative measures, or if there are pronounced anatomical changes in the acromion, the bottleneck can be reliably eliminated using modern arthroscopic surgical methods (keyhole technique).

The surgical procedure is called subacromial decompression or acromioplasty and is usually performed minimally invasively by means of arthroscopy. In this procedure, parts of the acromion and, if necessary, soft tissues are removed to reduce the tightness under the acromion and thus provide relief for the supraspinatus tendon or bursa. Our experienced shoulder specialists perform this operation and will be happy to advise you.

Everything at a glance:

• Operation time: 60 min
• Anesthesia: General anesthesia
• Hospitalization: outpatient, if necessary inpatient
• Fit for work: after approx. 4-6 weeks
• Return to sports (RTS): after approx. 12 weeks, depending on sport

After surgery, targeted physiotherapy should be started to prevent adhesions in the surgical area and to build up muscles.
Overhead work should be performed postoperatively after 6 weeks at the earliest, heavy loads on the arm not before 12 weeks.