Instability

Multidirectional Instability

Shoulder instability in multiple directions. Constitutional hyperlaxity. Conservative treatment first line (80% success).

The multidirectional instability (MDI) of the shoulder is defined by instability in at least 2 directions (anterior, posterior, inferior). It is distinguished from traumatic unidirectional instability by its atraumatic and often bilateral character. MDI is associated with constitutional hyperlaxity (Beighton score ≥ 4), redundant joint capsule and excessive capsular volume. It mainly affects young women and overhead athletes (swimming, volleyball, gymnastics). The key sign is the sulcus sign (inferior subluxation on downward traction). Treatment is primarily conservative (intensive rehabilitation 80% success) before considering arthroscopic capsular plication.

Characteristics

  • Shoulder pain and feeling of instability in multiple directions. Apprehension in various positions. Often bilateral. History of recurrent subluxations.
  • Sulcus sign: inferior subluxation on downward traction of the arm (grade 1: < 1 cm, grade 2: 1-2 cm, grade 3: > 2 cm). Sign persisting in external rotation suggests rotator interval lesion.
  • Beighton score for generalized hyperlaxity (thumb to forearm, elbow hyperextension > 10°, knee hyperextension, trunk flexion). Score ≥ 4/9 = constitutional hyperlaxity.
  • MR arthrography: increased capsular volume, redundant axillary recess, often absence of labral lesion (unlike traumatic instability). Enlarged rotator interval.

Medical and surgical management

  • First line: intensive specialized physiotherapy 3-6 months. Concentric and eccentric rotator cuff strengthening. Daily exercise program.
  • Conservative treatment failure: arthroscopic capsular plication (reduction of redundant joint capsule volume). Rotator interval closure.
  • Surgical alternatives: open capsular shift (modified Neer technique) if plication insufficient. Variable long-term results (70-85% good outcomes).

Physiotherapy rehabilitation

  • Conservative treatment first line (80% success rate). Intensive rotator cuff and scapular stabilizer strengthening program for 3-6 months minimum.
  • Specific strengthening of dynamic stabilizers: closed kinetic chain work, co-contractions, rhythmic stabilization exercises. Advanced multidirectional proprioception.
  • Correction of scapular dysfunction (scapular dyskinesis): lower trapezius and serratus anterior strengthening. Restore normal scapulohumeral rhythm.
  • If conservative treatment fails (6-12 months): arthroscopic capsular plication (capsular volume reduction). Cautious and prolonged post-operative rehabilitation (6 months).

Average duration

12 to 24 weeks of rehabilitation

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Scientific sources

General information only: this content cannot provide a diagnosis or prescription. A healthcare professional must assess your situation.