Instability

What is it?

The elbow is made up of three bony articulations between the distal humerus, the radial head and ulna, all of which are held in situ by ligamentous structures. Elbow instability is laxity of the joint, either as a result of damage to the bony or ligamentous structures acting to stabilize the joint. In the absence of supporting structures, the elbow is unstable and therefore free to slide in and out of place.

There are three types, depending on what structure is affected:

  • Posterolateral rotatory instability – most common type involving injury to the ligament supporting the outer aspect of the joint, the lateral collateral ligament complex.
  • Valgus instability – injury to the ligament on the inner aspect of the joint, the ulnar collateral ligament.
  • Varus posteromedial rotatory instability - injury to the lateral collateral ligament complex and a fracture of the coronoid – part of the ulna.

Why does it occur?

Chronic elbow instability is diagnosed when the elbow continues to slip in and out of place and all three of these types can be caused by trauma. Direct trauma to these supports, such as during a fall can potentially cause varying degrees of damage. Soft tissue injury, fracture or dislocation all lead to tight soft tissue constraints being weakened and susceptible to joint slippage.

Unlike the others, valgus stability is more commonly caused by repetitive strain on the ulnar collateral ligament. This is seen in athletes or job activities involving significant of overhead movement.

What are the symptoms?

Patients may experience discomfort with their elbow slipping or popping out of place. Certain movements may precipitate catching or locking of the elbow. Pain may be present overlying the affected area, and may indicate which structure is affected. 

How is it diagnosed?

Your clinician will need to take a thorough history and examination of the arm to establish which movements make the joint most unstable. Further imaging will also be required in the form of X-ray to establish any bony malalignment or fracture. In some cases an MRI is needed to assess the underlying condition of the supporting soft tissues.

How is it treated?

The ultimate treatment plan depends on the type of instability and the degree of severity, and is therefore decided on a case by case basis.

1. Non-surgical treatment

Physiotherapy is the mainstay of treatment, alongside anti-inflammatories and activity modification. This acts to restore strength in the muscles surrounding the elbow joint therefore increasing stability. Bracing is also effective in reducing symptoms through preventing joint slippage.

2. Surgical treatment

This may be required to regain full use of the elbow joint in cases of severe instability, fracture or failed conservative management. Ligament repair is often not achievable, therefore reconstruction using a tissue graft from another tendon is carried out. In those with additional bony injury, fracture fixation using screws and/or a plate will be done during the same operation.