Causes

Elbow instability is when the joint feels loose and moves more than it should when you use your arm. There are three types of elbow instability:

• Posterolateral rotator instability: the most common type, this is caused by an injury to the lateral collateral ligament (on the outside of the elbow) such as falling onto the hand when it is outstretched
• Valgus instability: caused by an injury to the ulnar collateral ligament (on the inside of the elbow), it is often due to repetitive stress or an accident
• Varus posteromedial rotatory instability: this is caused by an injury to the lateral collateral ligament complex along with a fracture to part of the ulna (on the inside of the elbow), often due to a fall

Symptoms

The elbow may slide out of place when you are moving your arm, as well as locking, feeling loose or as if it will pop out of place, for example when getting up from a chair. Athletes whose sport involves throwing may have pain on the inside of the elbow as well as a loss of throwing speed.

Diagnosis

Following a medical examination, the diagnosis is usually backed up by X-rays and an MRI scan.

Treatment

Non-surgical treatment: this may involve physiotherapy; avoiding activities where the elbow feels unstable; bracing the elbow to limit movement; and taking anti-inflammatory medication (if advised by your doctor).
Surgery: for competitive athletes this is often the only effective option and may involve ligament reconstruction or fracture fixation to improve strength and stability in the joint.