• www.sportordination.at
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  • www.sportordination.at
  • www.sportordination.at
  • www.sportordination.at

AC dislocation (= dislocation of the acromioclavicular joint)

The so-called AC joint (= acromioclavicular joint) is the connection between the external end of the clavicle and the acromion of the shoulder blade.

Dislocations in the acromioclavicular joint occur relatively frequently in physical contact-related types of sport, as well as in horse riding, cycling, skiing and wrestling. The injury is often caused directly by a fall onto the shoulder with adducted arm, and less commonly indirectly by a fall onto an outstretched hand. If the fixing capsule and ligaments accidentally rupture, the clavicle is displaced upwards due to the muscular traction - the clavicle dislocates upwards.

Depending on the extent of the injury, we talk about different degrees of injury, subdivided according to Tossy:

  • Tossy I: here only the joint capsule of the AC joint is overstretched, without considerable injury to the ligaments. The X-ray load images do not show any abnormalities at all.
  • Tossy II: the joint capsule, including the ligaments, is torn between the acromion and the clavicle (acromioclavicular ligaments). The coracoclavicular ligaments are stretched or torn. The lateral end of the clavicle is positioned up to half the shaft width of the clavicle higher than the acromion in the X-ray load images. The degree of severity represents the so-called subluxation position and has a tendency towards early-onset arthrosis as both bones are still in contact with each other and are rubbing together (there is therefore also an indication for surgery in the case of slightly dislocated Tossy II injuries).
  • Tossy III: all ligaments, including the joint capsule, are torn (including the coracoclavicular ligaments between the clavicle and coracoid). In the X-ray, the lateral end of the clavicle is more than one shaft width higher.



Typical clinical symptoms are pain over the AC joint and piano key phenomenon: By applying pressure from above to the lateral end of the clavicle, which is significantly raised, it can be pressed downwards similar to a piano key. When releasing the pressure, however, the clavicle raises again immediately.



Conservative: Tossy I AC joint injuries can be treated without an operation:

  • Immobilising dressing for a few days (arm sling or similar industrial dressings)
  • Analgesic and anti-inflammatory medications
  • Build up of mobility, by means of physiotherapeutic support, as required, after the initial pain has regressed



Injuries classified as Tossy II and Tossy III should be operated on.

In this operation, the dislocated end of the clavicle that has been pushed upwards is pushed down into its correct position. So that it stays in the correct position until the capsular ligaments heal, insertion of metal pins with wires, screws or even a plate is required. The ligaments and capsule can also be sutured.

Recently, stabilisation with a new dynamic system (the LARS ligament) has proven very useful.


Please note that medical indications and treatments change constantly. Sometimes these changes occur more rapidly than I am able to update on my homepage. Some information regarding dosage, prescription and compositions of medications may have changed in the meantime. Reading an internet page cannot replace visiting a doctor - it may be that during an examination and subsequent discussion with your doctor, other information is also communicated as a result of new scientific knowledge.