What is Multidirectional Instability of the Shoulder?
MDI of the shoulder is defined as generalized laxity (looseness) of the joint due to increased mobility and joint weakness. The shoulder joint may “slip” in and out of its socket in a forward (anterior), backward (posterior), or downward (inferior) direction. This “laxity” may be exaggerated in people who participate in activities that require repeated overhead movement of the arm, such as baseball pitchers or swimmers. The most common cause of MDI is overuse of the shoulder.
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How Does it Feel?
Symptoms of MDI of the shoulder may vary in terms of location and intensity. Although sometimes the shoulder can be dislocated, often people report their shoulder will “slip” out and go right back into the socket. They may also report instances where they feel like their shoulder is about to slip in and out of its socket, but they modify their activity to prevent it from happening. Pain may be felt in a number of areas around the shoulder—in the front of the shoulder when pitching a baseball, or throughout the entire shoulder after a repetitive activity like swimming. Since the symptoms of MDI vary widely, a health care professional will likely take a detailed history and perform a thorough physical exam to make an accurate diagnosis.
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Signs and Symptoms
Signs and symptoms of MDI of the shoulder vary from person to person, but may include:
Pain with pushing, pulling, or carrying heavy objects
Pain when performing an overhead activity
Pain during or after exercise
A feeling that the shoulder is “shifting” (including in bed at night)
Fear of putting the shoulder in certain positions
Numbness and tingling sensations in the affected arm
Clicking and popping sensations with movement
Weakness when performing athletic movements, especially overhead and away from the body
Loss of performance ability in sport activities
Fatigue with repetitive activity
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How Can a Physical Therapist Help?
Your physical therapist will evaluate your shoulder injury and find areas of weakness and muscular imbalance. The first step to treating the injury is managing pain and inflammation. Your physical therapist may advise you to stop or modify any activities that aggravate the injury, show you how to apply ice and heat to modulate the pain, and recommend the use of a sling for pain control.
The therapist will design an exercise program to improve your shoulder’s strength and stability. Initially, you’ll perform gentle exercises close to the body to limit your discomfort. After strength and stability have improved, your physical therapist will introduce more dynamic exercises specific to your activity goals.
Once your strength and range of motion have returned to a normal level, your physical therapist will help you gradually return to your sport activity. Throwing, playing, or swimming will typically begin in an interval format, allowing a progressive return to activity.