Shoulder subluxations are also called "dislocations" or "rotator cuff injuries." The "ball" at the end of the upper arm separates from the shoulder "socket." Once the ligament that holds the joint together has been damaged, the injury can reoccur from an action as simple as tossing paper in the wastebasket. If the shoulder subluxates often, surgery is a possibility. However, since surgery is expensive and risky, try these exercises first, with your doctor's approval. A few minutes of exercise a week strengthens the joint to prevent further injury.
Strengthen your rotator cuff. Just after the injury, even this may be a challenge. Standing or sitting, keep your elbow tucked in to your waist. Bend your arm 90 degrees. Rotate the upper arm, so that your hand moves out to your side. Then move the hand back to the starting position.
Add weights. When your shoulder has recovered, lie on your side, with your elbow nestling into your waist. Grip a free weight. Start with the weight on the floor by your navel. Keeping your elbow touching your waist, slowly raise the weight 90 degrees and slowly lower it. If you hold your elbow still, you will feel your shoulder rotate. Start with a weight that you can manage at 2 sets of 12 repetitions. As you strengthen, increase the weight. Repeat at least 3 times a week.
Use an exercise band anchored to a door as an option to weights. Stand with your injured shoulder facing the door. Tuck your elbow in to your waist; for best results put a rolled-up towel under the shoulder. Hold the band in your hand level with your elbow. Slowly pull your hand across your body, away from the door. Slowly release it. If you are not tired at the end of 2 sets of 12 repetitions, stand further away from the door, or use a heavier band. Repeat at least 3 times a week.
Stand with your injured shoulder away from the door. Begin in the same position as Step 3, but rotate your wrist out, away from the door. Repeat as above.