Shoulder sublaxation refers to a partial dislocation of the shoulder joint. It occurs when the upper arm bone (humerus) slips partially out of the socket (glenoid) due to weakness in the rotator cuff or a blow to the shoulder area.

The shoulder relies on strong ligaments and muscles to keep it stable and permit a wide range of movement in many directions. Sublaxation causes instability. In some cases, it may not be painful but may prevent an individual from taking part in sports and some daily activities. A traumatic first sublaxation may also lead to future dislocations, the shoulder giving out, or a feeling of instability.

Sublaxation tends to occur more frequently in three groups of people:

  • Young athletes who compete in sports involving overhead activities, such as volleyball players, swimmers, baseball pitchers and weightlifters. The feeling of instability may interfere with their ability to play these sports.
  • Individuals with joint laxity (loose shoulder joints) or double-jointedness. The laxity may lead to shoulder instability or sublaxation.
  • Individuals who have experienced previous shoulder sublaxation. If the ligaments that support the shoulder are torn when the dislocation occurs and heal too loosely, they may be at greater risk of repeat sublaxation and instability.

A shoulder specialist at Lancaster Orthopedic Group will perform tests to determine why the shoulder sublaxation occurred. Conservative treatment includes physiotherapy and muscle strengthening exercises to help maintain the shoulder in proper position. Other treatments include cortisone injections and anti- inflammatory medications. In some cases, surgery may be an option to repair and strengthen the ligaments that keep the shoulder in the joint.