Thrower's shoulder

Thrower's shoulder describes complaints caused by functional and structural changes to the shoulder joint in the course of overhead and throwing sports such as swimming, handball, volleyball or tennis.

Throwing movements can be divided into three phases: In the first phase of a throwing movement, the arm is spread out and rotated outwards as far as possible. The arm is then moved forward in the so-called acceleration phase. This is followed by the deceleration phase, which is associated with a high load on the shoulder joint, particularly the posterior parts of the joint capsule.

Repetitive throwing movements therefore lead to enormous load peaks in the shoulder joint as well as to adaptation processes in order to enable the best possible throwing. These associated changes can lead to structural injuries in the shoulder joint over time.

The shoulder joint is considered to be both the most mobile and the most complicated joint in the human body, which makes it susceptible to discomfort and injury. It consists of a complex system of bones, ligaments, bursae and tendons and is formed by the head of the upper arm (humeral head) and the glenoid cavity, which is part of the shoulder blade (scapula). The glenoid cavity is surrounded by a joint lip (labrum), the shoulder joint by a joint capsule. The acromion lies above the joint. The head of the humerus is larger than average in relation to its socket, which leads to a large range of movement in the shoulder, but also to a certain degree of instability. The shoulder joint is stabilized by 4 muscles, which together form the so-called rotator cuff . The supraspinatus tendon runs right between the humeral head and the acromion, which means that this tendon is often affected by shoulder tightness syndrome.

Signs of a thrower's shoulder can be:

• Shoulder pain on exertion
• Restricted movement (especially internal rotation)

Typically, those affected suffer from load-dependent shoulder pain, which occurs particularly during throwing movements and increases over time. In addition, the high load on the posterior joint capsule leads to shrinkage and thickening of the capsule at this point, which results in reduced internal rotation of the shoulder. This phenomenon is known in specialist circles as glenohumeral internal rotation deficit (GIRD). Due to the maximum external rotation during throwing movements, there is a simultaneous stretching of the anterior joint capsule and thus an excessive external rotation capacity compared to the opposite side.

The symptoms can lead to a temporary inability to exercise, which significantly reduces the quality of life of those affected.

The overriding cause of throwing shoulder is the regular practice of throwing and overhead sports (swimming, handball, volleyball, tennis, baseball, basketball). The repetitive throwing movements can lead to overloading of the shoulder joint and thus to microtraumas , which in turn leads to further changes.

Causes of a thrower's shoulder include

• Thickening and shrinkage of the posterior joint capsule, stretching of the anterior joint capsule ⇒ reduced internal rotation, increased external rotation
• Secondary structural damage, e.g. rotator cuff lesion, biceps tendon tear, internal impingement
• Muscular imbalances

As mentioned above, the posterior joint capsule is subjected to enormous strain, particularly during the deceleration phase of throwing movements, resulting in a contraction of the capsule, which restricts the shoulder joint's ability to internally rotate. The pronounced external rotation at the beginning of the throwing movements leads to a stretching of the anterior parts of the joint capsule, which in turn results in an increased ability to rotate externally.

This results in changes in the biomechanics of the shoulder joint and possibly further secondary structural damage. Among other things, the humeral head becomes elevated, which favors the development of internal impingement. In internal impingement, the supraspinatus tendon of the rotator cuff is not trapped between the humeral head and acromion as in external impingement, but by the glenoid rim. In addition, inflammation, partial tears and complete ruptures of the rotator cuff can be observed. Injuries to the long biceps tendon (SLAP lesion), the joint capsule or the joint lip (labrum) are also possible.

Muscular imbalances caused by one-sided strain further exacerbate the problem.

Our certified sports physician Dr. med. Tarek Schlehuber will ask you about your complaints in a detailed consultation. This is followed by a thorough examination of the shoulder joint with regard to the range of motion and accompanying structural damage. Typically, limited internal rotation and increased external rotation are noticeable. A medical history and physical examination are usually sufficient to make a diagnosis.

Imaging procedures such as ultrasound and/or magnetic resonance imaging (MRI) are used to rule out structural damage. In most cases, the typical changes in the joint capsule (contraction of the posterior parts, stretching of the anterior parts) are also visible.

The aim of the treatment is to restore the patient's original performance and quality of life.

Conservative therapy:

The following conservative therapies are possible:

• Protection
• Physiotherapy
• Painkillers
• Cooling pads

As part of the initial treatment, patients should make sure to take the strain off their shoulder joint. The duration and extent of the relief is determined individually in consultation with your doctor and can range from a slight reduction and change in load to a week-long break from sport.

One of the most important components of therapy is the implementation of physiotherapy with the following objectives: Stretching the posterior parts of the joint capsule, strengthening the surrounding muscles, compensating for muscular imbalances, improving mobility (especially the ability to rotate internally).

For acute pain relief, patients can take short-term painkillers from the group of non-steroidal anti-inflammatory drugs (NSAIDs) and/or apply a cooling pad wrapped in a kitchen towel to the affected area.

Operation:

Surgery may be necessary if conservative treatment measures have failed and/or if there is existing structural damage. In the vast majority of cases, this operation is performed using a minimally invasive(arthroscopic ) technique, i.e. a camera with a light source and a working instrument are inserted through incisions in the skin just a few centimetres long. This allows changes in the shoulder joint to be precisely assessed and then treated directly.

The surgical technique depends on the injury constellation and patient-specific factors. In the case of a rotator cuff lesion, the torn tendon is reattached to the humerus during the operation (rotator cuff suture). A so-called SLAP lesion, i.e. a tear or rupture of the long biceps tendon at the upper edge of the glenoid cavity with tearing of the glenoid lip, can also be treated arthroscopically. The tendon is refixed together with the detached parts of the labrum using a suture anchor in the area of the glenoid cavity. Alternatively, the long biceps tendon can be severed during the operation (tenotomy), which can then be reattached in another bony or soft tissue location during the course of the operation (tenodesis).

The follow-up treatment depends on the operation performed, see Rotator cuff lesion and biceps tendon rupture.