What causes shoulder dislocation?
Reference has already been made to the distinction between traumatic and atraumatic shoulder dislocation. The respective causes for the development of the two forms of shoulder dislocation are described in more detail below. The posttraumatic recurrent shoulder dislocation presupposes a traumatic initial dislocation and can therefore be considered a partial form of traumatic shoulder dislocation.
The causes of a traumatic shoulder dislocation can be found, for example, in For example, it occurs most frequently as a result of a fall: When trying to restrain the arm, the shoulder joint is suddenly subjected to great pressure and may be unfavorably rotated. For this reason, the supporting apparatus of ligaments and muscles can no longer hold the joint and it becomes dislocated. The same can happen in some sports, such as tennis, skiing and handball.
Depending on the direction in which the force is applied and thus the dislocation, a distinction is made between anterior, posterior and lower shoulder dislocation, with the anterior shoulder dislocation being by far the most common. The classic cause of a front shoulder dislocation is a fall to the back, in which the arm falls unhappily on the ground. While sports accidents are the most common cause of shoulder dislocations in young people, the risk of falling is a major risk in older people.
In addition, the stability of ligaments and muscles in the body often decreases over the years. Previous dislocations also represent a risk factor, as the ligament apparatus lends itself out over time to some extent.
- Accidents or
- Effects of force
The causes and injury mechanisms of posttraumatic recurrent shoulder dislocation are considered to be largely understood.
They are considered to be “recurrent” because of their name, so that a traumatic (accident-related) initial dislocation must already have occurred, which in addition may not have healed as planned. The most common causes of posttraumatic recurrent shoulder dislocation are
- Remaining damage after traumatic initial luxation, which usually occurs for the first time in adulthood.
- Cartilaginous/bony Bankart lesion (= tear of the labrum glenoidale in the context of an anterior shoulder joint luxation)
- Hill-Sachs lesion (= impression on the dorsolateral (towards the back, lateral) edge of the humeral head; in habitual dislocation)
- Weakness of the capsule-ligament apparatus
- Loss of proprioception (= loss of perception and control of the position of the body in space; sensory disorder)
- Muscle weakness despite adequate rehabilitation
In the area of habitual shoulder dislocation, both the aetiology and the pathogenesis of the disease are not yet sufficiently clarified. Classically, a first dislocation is present in this subgrouping, which is usually directed to the processus coracoidia (= coracoid process). A habitual first dislocation occurs mainly in childhood and adolescence. Usually an instability remains, which is usually very painless.In addition, certain factors are assumed to have a favourable effect on the development of a habitual shoulder dislocation:
- Anomalies in the area of the capsule-ligament apparatus
- Changed collagen cross-linking or composition of the capsule
- Dysplasia of the glenoid cavity (reduced glenoid contact)
- Increased inclination of the socket to the front, reduced rotation of the humeral head to the rear
- Congenital connective tissue weakness Ehlers-Danlos syndrome (hyperelasticity, increased vulnerability and wound healing disorder of the skin, joint hyperextension with a tendency to dislocation; hereditary clinical picture) Marfan syndrome (hereditary clinical picture, special connective tissue disease: changes in the eyes, habitus and cardiovascular system)
- Ehlers-Danlos syndrome (hyperelasticity, increased vulnerability and wound healing disorder of the skin, hyperextension of joints with a tendency to dislocation; hereditary clinical picture)
- Marfan syndrome (hereditary clinical picture, special connective tissue disease: changes in the eyes, habitus and cardiovascular system)
- Muscular dysfunction
- Ehlers-Danlos syndrome (hyperelasticity, increased vulnerability and wound healing disorder of the skin, hyperextension of joints with a tendency to dislocation; hereditary clinical picture)
- Marfan syndrome (hereditary clinical picture, special connective tissue disease: changes in the eyes, habitus and cardiovascular system)
