Causes and Risk Factors
Joint instability can develop because of:
- Trauma or injury. If the shoulder joint is injured, the labrum can be torn. The labrum is like a cuff that extends and cushions the socket of the shoulder joint. It also serves as an attachment point for the ligaments that help hold the shoulder joint stable.
- This is most common in young people who are active in sports. These activities can cause injuries or dislocation of the shoulder joint. The younger and more active a person is the first time he or she has a shoulder dislocation, the more likely it is that instability will develop. Older people can develop joint instability after a fall or injury to their shoulder joints.
- Repetitive motions. A person who is active in swimming, gymnastics or sports that require throwing may make the same overhead motions again and again. Overtime, this can cause wear and tear on the joint. It may stretch the capsule that surrounds the shoulder joint, making the joint loose and unstable.
- Factors that a person is born with. These factors can cause general looseness in the joint and surrounding ligaments, tendons and muscles that cause the shoulder to become unstable. The greater motion of the loose joint can lead to tears in the labrum and other damage to the joint.