Complete Guide for Patients & Clinicians
Quick Facts
- What is it? A condition where the shoulder’s upper arm bone (humeral head) slips partially or fully forward from the socket.
- Who’s affected? Over 95% of shoulder instability cases are anterior. Peak risk for males aged 16–20 and athletes in contact/overhead sports.
- Why it matters: Can lead to recurrences, nerve or joint damage, and long-term pain or arthritis.
- What Causes Shoulder Instability?
Classic Patterns
- TUBS (Traumatic, Unilateral, Bankart lesion, Surgery): Typically due to injury with a labral tear, often requiring surgery.
- AMBRI (Atraumatic, Multidirectional, Bilateral, Rehab, Inferior capsular shift): Involves looseness across directions, treated with physical therapy.
Modern Approach
- Direction. Often unidirectional (anterior); can be multidirectional (MDI).
- Injury source. Acute trauma vs. repetitive micro-injury.
- Tissue laxity. Congenital or acquired looseness affects treatment.
- Who Gets It?
- General: Lifetime risk ~1–2%. Men are disproportionately affected (~72%).
- Athletes: Higher in contact/overhead sports.
- Teens: Peak incidence at age 16 (164 per 100,000). Recurrence is highest in 14–16 year-olds (37–42%).
- What Happens Inside the Shoulder?
- Static stabilisers: Labrum, joint capsule, ligaments.
- Dynamic stabilisers: Rotator cuff, deltoid, scapular muscles.
When these structures are injured—often via trauma—stability is disrupted.
Common Injuries
- Bankart Lesion: Tear of the anterior labrum.
- Bony Bankart: Bone fragment from the front rim of the socket.
- Hill-Sachs Lesion: A dent on the back of the humeral head; “engaging” ones hit the socket’s rim and cause instability.
- Glenoid Bone Loss: >20–25% bone loss often requires surgical solutions.
- How Is It Diagnosed?
History & Exam
- Ask about injuries, direction of slipping, previous events, sports activity.
- Check shoulder motion, muscle strength, perform Anterior Apprehension, Jobe Relocation, and Load-and-Shifttests.
- Evaluate for general joint laxity (e.g. via Beighton score).
Imaging
- X-rays (AP, scapular Y, axillary): Assess bone position and damage.
- MRI/MR Arthrogram: Detect soft tissue injuries (labral tears).
- CT 3D scan: Quantify bone loss for surgical planning.
- How Is It Treated?
Non-Surgical (Initial)
- Often used for a first-time dislocation with minimal bone damage.
- Begins with 1–2 weeks in a sling, followed by physical therapy to strengthen stabilizers and restore movement.
- Some athletes use bracing and return to sport after ~2–3 weeks.
Surgical (When Surgery Is Ideal)
- Indications include recurrent dislocation, high-demand athletes, and significant bone injuries.
- Arthroscopic Bankart Repair: Reattaches the labrum to the socket.
- Remplissage: Fills defects on the humeral head (Hill-Sachs) to prevent “engagement.”
- Bone block procedures (e.g., Latarjet, Eden-Hybinette): Add bone to the socket; suited for large bone loss.
- Rehabilitation After Surgery
- Phase 1 (Weeks 0–6): Sling use; gentle elbow motion.
- Phase 2 (Weeks 6–10): Gradual shoulder motion resume (avoid full external rotation until ~8 weeks).
- Phase 3 (Weeks 10–12+): Strengthening rotator cuff and scapular muscles.
- Return to sports: Earliest ~3 months; contact sports often require ~6 months.
- What to Expect
Recurrence Risk
- Evaluated using the Instability Severity Index Score (ISIS):
- Score ≤ 3 → ~94% 5‑year success
- Score 4–6 → ~85% success
- Score > 6 → ~55% success; open surgery may be needed
Possible Complications
- Redislocation (especially with unrecognized bone flaws)
- Stiffness or loss of motion
- Nerve irritations (e.g. axillary)
- Surgical site infections
- Osteoarthritis, especially if untreated or overtightened
- Keeping Shoulders Strong
- Education: Awareness of symptoms, warm-up practices, safe mechanics
- Strength training: Focus on rotator cuff and scapular stabilizers
- Warm-up protocols: Band exercises, dynamic stretching before activity
Meet the Team
Effective care involves a coordinated interprofessional team:
- Athletic trainers
- Sports medicine and family physicians
- Orthopedic surgeons
- Physiotherapists
- Rehabilitation nurses
Frequently Asked Questions
Is my shoulder just loose or truly unstable?
Loose shoulders (laxity) allow extra movement without symptoms. Instability causes pain, weakness, or repeated slips.
When is imaging needed?
X-rays are routine. MRI shows labral damage. CT scans are essential if bone injury is suspected—vital for planning surgery.
Who needs surgery?
Young, active patients in demanding sports—or anyone with recurrent dislocations, large bone loss, or labral tears—should discuss surgery early.
When can I return to sports?
Non-contact sports: around 3 months. Contact sports typically require 6 months after surgery. Full recovery depends on individual progress.
Call to Action
If you have pain, book an appointment to be reviewed by Prof Imam or another member of our specialist team at The Arm Clinic. Early specialist care helps prevent long-term issues. Visit www.TheArmDoc.co.uk or book your consultation today. Phone: 020 3384 5588 | Email: Info@TheArmDoc.co.uk
Disclaimer
This information is for general educational purposes and should not be used as a substitute for professional medical advice. Consult a healthcare professional for individual guidance on your condition and treatment options.
This page was last clinically updated in May 2025
Glossary: Access our interactive section for definitions of key terms like Bankart lesion, Hill‑Sachs lesion, Latarjet, and more.