If a past shoulder dislocation or strain is still bothering you, you may have shoulder instability.

Shoulder instability, or a loose shoulder joint, can affect your daily life and sports performance.

“Instability occurs when you have a loose or torn ligament,” said Dr. Darren Corteen, a Marshfield Clinic orthopedic surgeon and sports medicine physician. “An unstable shoulder is easily dislocated and can be painful.”

Your shoulder may give out easily, slide out of position, or feel like it’s “clunking” or popping. Reaching overhead, throwing a ball or swimming may be especially difficult and painful.

Make an appointment with your doctor if you have these symptoms after a shoulder injury or strain. Your doctor will check your shoulder strength and mobility to diagnose instability.

Most common in athletes

Types of shoulder instability include traumatic and atraumatic.

Traumatic instability is caused by a force that dislocates the shoulder, such as a hard hit in football or hockey. It also can happen during a bad fall or car accident. A traumatic dislocation usually results in a trip to the emergency department.

A dislocated shoulder may be a one-time event if you don’t participate in contact sports, but frequent hard hits put you at risk for multiple dislocations, Corteen said.

Atraumatic instability develops when a less serious injury or strain causes the ligaments to loosen over time and the shoulder to slide out of place. This type is often seen in volleyball players and swimmers, but some people who have naturally loose ligaments can have instability.

Treatment is physical therapy or surgery

“Physical therapy is the first-line treatment for atraumatic shoulder instability,” Corteen said. “Strengthening the shoulder girdle muscles can increase stability for people with atraumatic instability.”

Pain medication or cortisone injections can reduce swelling to make physical therapy easier if you have a painful shoulder.

Surgery is often necessary if several months of physical therapy doesn’t help or you have torn ligaments from a traumatic shoulder injury. Surgery repairs torn ligaments or tightens loose ligaments to stabilize the shoulder.