Core message • Do not treat anterior instability only by counting dislocations. • Decision-making should combine age, sport type, hyperlaxity, glenoid bone loss, Hill-Sachs morphology, and glenoid track status. • Isolated Bankart repair is most reliable in low-risk patients with minimal bone loss and an on-track Hill-Sachs lesion. |
1. Snapshot
· Typical patient: young active male after traumatic anterior glenohumeral dislocation.
· Main problem: recurrence, progressive capsulolabral injury, bipolar bone loss, and impaired sport performance.
· Highest recurrence risk: young age, contact/collision sport, competitive sport, hyperlaxity, glenoid bone loss, off-track Hill-Sachs lesion, and failed prior stabilization.
· Treatment goal: restore stability while preserving motion and allowing safe return to activity.
2. Classification
Type | Key features | Initial management concept |
Traumatic anterior instability | Clear traumatic event; Bankart lesion, Hill-Sachs lesion, capsular injury, variable glenoid bone loss. | Risk-stratify; early stabilization is often considered in young high-risk athletes. |
Recurrent anterior instability | Repeated dislocation or subluxation episodes; increasing risk of glenoid and humeral bone loss. | Assess bipolar bone loss; choose Bankart, Bankart + remplissage, or bone-block procedure. |
Atraumatic / multidirectional instability | Capsular redundancy, generalized laxity, abnormal muscle patterning; may be bilateral. | Structured physiotherapy and neuromuscular control first; surgery only for selected refractory cases. |
3. History and Physical Examination
History: must ask
· Age at first dislocation and current age.
· Number of dislocations and subluxations; need for reduction.
· Mechanism and arm position during instability.
· Sport: contact/collision, forced overhead, competitive level.
· Neurologic symptoms, prior surgery, voluntary subluxation, generalized laxity.
High-yield tests
Test | Positive finding | Pearl |
Apprehension | Sense of impending dislocation in abduction-external rotation. | Apprehension is more specific than pain alone. |
Relocation | Posteriorly directed force reduces apprehension. | Supports anterior instability. |
Release / surprise | Apprehension returns when posterior force is removed. | Use carefully. |
Load-and-shift | Increased anterior/posterior translation. | Compare with contralateral side. |
Sulcus sign | Inferior translation / sulcus below acromion. | Suggests inferior laxity or MDI. |
Gagey hyperabduction | >20 degrees side-to-side difference. | Suggests inferior glenohumeral ligament laxity. |
Beighton score | Commonly >=4/9 for generalized hyperlaxity. | Thresholds vary by age and population. |
4. Imaging
Modality | Use | Key notes |
Plain radiographs | Initial assessment after dislocation. | True AP/Grashey, scapular Y, and axillary views. Axillary view helps avoid missed posterior dislocation/subluxation. |
Special radiographic views | Detect Hill-Sachs and glenoid rim deficiency. | Stryker notch: Hill-Sachs. West Point/Bernageau: anterior glenoid bone loss. |
3D CT | Best practical tool for quantifying glenoid bone loss and bipolar defects. | Use en face glenoid views; compare with contralateral side when needed. |
MRI / MR arthrography | Labrum, capsule, rotator cuff, chondral lesions, HAGL, ALPSA, Perthes. | MR arthrography can improve detection of subtle chronic capsulolabral lesions. |
5. Common Lesions
· Bankart lesion: detachment of the anteroinferior labrum and IGHL complex from the glenoid rim.
· Bony Bankart: anteroinferior glenoid rim fracture with labral detachment.
· ALPSA: anterior labroligamentous periosteal sleeve avulsion; labrum displaced medially/inferiorly with intact periosteum.
· Perthes lesion: labral avulsion with intact periosteum and minimal displacement.
· HAGL lesion: humeral avulsion of the glenohumeral ligament; suspect when instability is present without classic Bankart lesion.
· Hill-Sachs lesion: posterolateral humeral head compression defect from impaction on the anterior glenoid rim.
6. Bipolar Bone Loss and Glenoid Track
Glenoid track concept • On-track: Hill-Sachs lesion remains within the glenoid track; engagement is unlikely. • Off-track: Hill-Sachs lesion extends medially beyond the glenoid track; isolated Bankart repair has higher failure risk. • Always evaluate both sides of the joint: glenoid bone loss + humeral head defect. |
Calculation
1. Measure intact glenoid width: D.
2. Expected glenoid track width = 0.83 x D.
3. Measure glenoid bone loss: d.
4. True glenoid track = 0.83D - d.
5. Measure Hill-Sachs interval = Hill-Sachs width + bone bridge from rotator cuff footprint to lateral margin of the lesion.
6. If Hill-Sachs interval <= true glenoid track: on-track. If Hill-Sachs interval > true glenoid track: off-track.
7. Instability Severity Index Score (ISIS)
Factor | Criteria | Points |
Age at surgery | <=20 years | 2 |
Sport level | Competitive sport | 2 |
Sport type | Contact or forced overhead sport | 1 |
Hyperlaxity | ER >85 degrees or positive Gagey test | 1 |
Hill-Sachs on AP radiograph | Visible in external rotation | 2 |
Glenoid contour loss | Loss of inferior glenoid contour | 2 |
· Maximum score: 10 points.
· High ISIS suggests increased recurrence risk after isolated arthroscopic Bankart repair.
· Do not use ISIS alone; integrate glenoid bone loss, glenoid track status, age, sport, hyperlaxity, tissue quality, and revision status.
8. Treatment Algorithm
Clinical scenario | Preferred strategy | Key rationale |
First-time dislocation, older/low-demand, no significant bone loss | Nonoperative treatment | Short-term sling + structured rehabilitation; recurrence risk is lower than in young collision athletes. |
Young active patient, Bankart lesion, minimal bone loss, on-track Hill-Sachs | Arthroscopic Bankart repair | Restores capsulolabral bumper and tension. |
Off-track or engaging Hill-Sachs with minimal/subcritical glenoid bone loss | Bankart repair + remplissage | Addresses humeral-sided defect and reduces engagement risk. |
Critical glenoid bone loss, high-risk collision athlete, failed Bankart, poor tissue quality | Latarjet or other bone-block procedure | Bone-block + sling effect + capsular repair improves stability. |
Atraumatic/MDI or voluntary instability | Rehabilitation first | Focus on scapular control, rotator cuff, proprioception, and muscle-pattern correction. |
9. Surgical Options: One-Line Summary
Procedure | Best indication | Pitfall |
Arthroscopic Bankart | Low-to-moderate risk traumatic anterior instability; minimal bone loss; on-track lesion. | Fails if significant bone loss or off-track Hill-Sachs is ignored. |
Bankart + remplissage | Off-track/engaging Hill-Sachs with minimal or subcritical glenoid bone loss. | May slightly limit external rotation; avoid over-tensioning. |
Latarjet | Critical glenoid bone loss, high-risk collision athlete, failed soft-tissue repair, selected off-track bipolar lesions. | Complications include graft malposition, nonunion/resorption, hardware problems, neurovascular injury. |
Free bone-block grafting | Large glenoid defect or failed coracoid transfer / revision setting. | Requires precise graft sizing and placement. |
10. Rehabilitation and Return to Sport
· Protocol depends on procedure, tissue quality, associated lesions, and surgeon preference.
· Early phase: protect repair, sling as indicated, pain control, hand/wrist/elbow motion.
· Intermediate phase: gradual passive and active-assisted ROM; avoid stressing the repair too early.
· Strength phase: rotator cuff, scapular stabilizers, proprioception, kinetic chain.
· Return to sport: after symmetric strength, functional testing, confidence, and sport-specific progression; contact/collision sport commonly delayed until about 4-6 months or later.
11. Complications and Causes of Failure
Complications | Common failure factors |
Recurrent instability, stiffness, loss of external rotation, persistent apprehension, infection, neurovascular injury, anchor/chondral complications. | Unrecognized glenoid bone loss, untreated off-track Hill-Sachs, inadequate capsulolabral repair, hyperlaxity, young age, collision sport, poor tissue quality, poor rehab compliance. |
After Latarjet: graft malposition, nonunion, resorption, screw irritation, arthritis risk, musculocutaneous/axillary nerve injury. | Graft too medial/lateral, insufficient fixation, unaddressed humeral defect, technical errors, premature return to collision sport. |
12. Exam Pearls
· Apprehension is more specific than pain during the apprehension test.
· Always obtain an axillary view in acute shoulder dislocation evaluation.
· In recurrent anterior instability, always quantify bone loss.
· Off-track Hill-Sachs lesions have a high risk of failure after isolated Bankart repair.
· Subcritical glenoid bone loss can still matter, especially in young contact athletes.
· Bankart repairs the soft-tissue lesion; remplissage addresses humeral-sided engagement; Latarjet addresses glenoid deficiency and high-risk instability.
· ISIS is a helpful historical risk score, not a standalone surgical algorithm.
· Recurrent instability episodes may progressively increase bipolar bone loss.
References
Thomas Amouyel, Pauline Duriez, Clément Lalanne, Christophe Szymanski, Valérie Deken, Christophe Chantelot, Peter Upex, Carlos Maynou (2021). Arthroscopic Bankart Repair Versus Immobilization for First Episode of Anterior Shoulder Dislocation Before the Age of 25: A Randomized Controlled Trial. The American Journal of Sports Medicine.
Eiji Itoi (2017). On-track and off-track shoulder lesions. EFORT Open Reviews.
Frédéric Balg, Pascal Boileau (2007). The instability severity index score: A simple pre-operative score to select patients for arthroscopic or open shoulder stabilisation. Journal of Bone and Joint Surgery [British].
Colin M. Robinson, J. Howes, R. Buller, et al. (2006). Functional outcome and risk of recurrent instability after primary traumatic anterior shoulder dislocation in young patients. Journal of Bone and Joint Surgery [American].
Giovanni Di Giacomo, Eiji Itoi, Stephen S. Burkhart (2014). Evolving concept of bipolar bone loss and the Hill-Sachs lesion: from “engaging/non-engaging” lesion to “on-track/off-track” lesion. Arthroscopy: The Journal of Arthroscopic & Related Surgery.
Nobuyuki Yamamoto, Eiji Itoi, Hirotaka Abe, et al. (2007). Contact between the glenoid and the humeral head in abduction, external rotation, and horizontal extension: a new concept of glenoid track. Journal of Shoulder and Elbow Surgery.
Stephen S. Burkhart, Joide F. De Beer (2000). Traumatic glenohumeral bone defects and their relationship to failure of arthroscopic Bankart repairs: significance of the inverted-pear glenoid and the humeral engaging Hill-Sachs lesion. Arthroscopy: The Journal of Arthroscopic & Related Surgery.
Pascal Boileau, M. Villalba, J. Héry, et al. (2006). Risk factors for recurrence of shoulder instability after arthroscopic Bankart repair. Journal of Bone and Joint Surgery [American].
Lennart Hovelius, A. Olofsson, B. Sandström, et al. (2008). Nonoperative treatment of primary anterior shoulder dislocation in patients forty years of age and younger: a prospective twenty-five-year follow-up. Journal of Bone and Joint Surgery [American].
Carter R. Rowe, Bertram Zarins, J. V. Cuillo (1984). Recurrent anterior dislocation of the shoulder after surgical repair. Journal of Bone and Joint Surgery [American].
Frederick A. Matsen III, Donald T. Harryman II, John A. Sidles (1991). Mechanics of glenohumeral instability. Clinics in Sports Medicine.
Gilles Walch, Pascal Boileau, C. Levigne, et al. (1995). Arthroscopic stabilization for recurrent anterior shoulder dislocation: results of 59 cases. Arthroscopy: The Journal of Arthroscopic & Related Surgery.
Stephen M. Howell, Brian J. Galinat (1989). The glenoid-labral socket: A constrained articular surface. Clinical Orthopaedics and Related Research.