Shoulder pain can be frustrating—especially when it feels like your shoulder slips, pops, or just doesn’t feel stable. One lesser-known cause of shoulder discomfort is Multidirectional Instability (MDI).
What is MDI?
MDI means your shoulder is unstable in two or more directions—it might feel like it’s slipping forward, backward, or downward. This can happen without a major injury and is more common in young people aged 12–35, especially those involved in sports like swimming, gymnastics, or throwing.
Common Signs of MDI
- Shoulder pain during activity, even without injury
- A feeling of looseness, slipping, or popping
- Muscle weakness or unusual shoulder movement
Why It Happens
MDI can be linked to:
- Naturally loose joints (hypermobility)
- Repetitive strain from sports or work
- Genetic conditions like Ehlers-Danlos or Marfan syndrome
- Changes in shoulder muscle control or posture
How It’s Diagnosed
Physiotherapists use a combination of movement tests and your symptoms to assess shoulder stability. It’s important to know that joint looseness isn’t always a problem—MDI is only diagnosed when it causes pain or affects your function.
What Can Be Done?
Treatment usually focuses on rehabilitation, not surgery. Strengthening shoulder muscles and improving movement patterns can help restore stability and reduce pain.