High Yield Overview

Multidirectional Instability (MDI)

Symptomatic shoulder instability in 2+ directions without significant trauma

Symptomatic instability in ≥2 directions without significant traumaDefinition

15-25 years, female predominance 2:1Peak Incidence

≥4/9 suggests generalized hypermobilityBeighton Score

80-90% with structured rehabilitationConservative Success

Over 2cm indicates severe inferior laxitySulcus Sign Grade III

Stanmore Triangle Classification

Pattern

Treatment

Pattern

Treatment

Pattern

Treatment

Critical Must-Knows

MDI is clinical diagnosis: symptomatic instability in 2+ directions without significant trauma
Rehabilitation is first-line: minimum 6 months structured physiotherapy before surgery
Sulcus sign pathognomonic: measure in adduction and external rotation positions
Beighton score ≥4/9 indicates generalized hypermobility affecting treatment decisions
Inferior capsular shift gold standard open procedure: T-capsulorrhaphy or lateral shift
Arthroscopic capsulorrhaphy success rates 70-85%: lower than unidirectional instability
Thermal capsulorrhaphy abandoned: high failure rates and chondrolysis risk
Burkhead-Rockwood protocol: structured 6-12 month rehabilitation program

Examiner's Pearls

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Examine BOTH shoulders: bilateral involvement in 50-80% of MDI patients
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Sulcus sign graded with shoulder in neutral rotation AND external rotation
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Positive sulcus in ER suggests rotator interval pathology requiring specific treatment
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Load-and-shift test: compare to contralateral shoulder, grade on 3-point scale
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Hyperabduction test: humeral head translation with arm overhead indicates inferior laxity
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Apprehension test often NEGATIVE in MDI: distinguishes from traumatic instability
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Document generalized hypermobility: affects surgical planning and expectations

Clinical Imaging

Imaging Gallery

Posteroinferior capsular shift (16 years, female). Left shoulder, lateral position; view from anterosuperior. H: Humerus, G: Glenoid, pC: posterior Capsule, pCP: posterior Capsular Plication. — Posteroinferior capsular shift (16 years, female). Left shoulder, lateral position; view from anterosuperior. H: Humerus, G: Glenoid, pC: posterior CaCredit: Voigt C et al. via Open Orthop J via Open-i (NIH) (Open Access (CC BY))

Anteroinferior capsular shift (16 years, female). Left shoulder, lateral position; view from anterosuperior. H: Humerus, G: Glenoid, aC: anterior Capsule, aCP: anterior Capsular Plication, MGHL: Media — Anteroinferior capsular shift (16 years, female). Left shoulder, lateral position; view from anterosuperior. H: Humerus, G: Glenoid, aC: anterior CapsCredit: Voigt C et al. via Open Orthop J via Open-i (NIH) (Open Access (CC BY))

Interval closure (16 years, female). Left shoulder, lateral position; view from dorsal. H: Humerus, G: Glenoid, IC: Interval Closure, LBT: Long Bicipital Tendon, SSC: M. subscapularis. — Interval closure (16 years, female). Left shoulder, lateral position; view from dorsal. H: Humerus, G: Glenoid, IC: Interval Closure, LBT: Long BicipiCredit: Voigt C et al. via Open Orthop J via Open-i (NIH) (Open Access (CC BY))

Critical Exam Errors in MDI Assessment

Diagnostic Pitfalls

Missing bilateral examination (50-80% bilateral involvement), confusing MDI with unidirectional instability (completely different algorithms), failing to assess sulcus sign in external rotation (rotator interval indicator), not documenting generalized hypermobility (Beighton score affects decisions), overlooking voluntary component (psychiatric assessment may be needed), and premature surgical intervention (rehabilitation is first-line with 80-90% success). MDI is a clinical diagnosis requiring comprehensive bilateral examination.

Management Errors

Inadequate rehabilitation trial (minimum 6 months required), wrong surgical procedure (thermal capsulorrhaphy abandoned), excessive capsular shift (overtightening causes stiffness), missing rotator interval closure (persistent sulcus in ER), inadequate postoperative protection (early mobilization causes recurrent stretching), and unrealistic expectations (MDI surgery has lower success than unidirectional). Conservative management succeeds in 80-90% with proper compliance.

Examination Technique Errors

Improper sulcus sign technique (test in adduction, neutral, and ER), inadequate load-and-shift grading (compare to contralateral), missing hyperabduction test (specific for inferior laxity), failing to examine under anesthesia (reveals true laxity), not assessing voluntary control (distinguishes structural from non-structural), and overlooking associated pathology (labral tears can coexist). Systematic bilateral examination is essential.

Surgical Pitfalls

Arthroscopic capsulorrhaphy in severe MDI (open shift has better outcomes), inadequate capsular volume reduction (inferior pouch must be addressed), missing rotator interval closure (when sulcus positive in ER), over-tensioning capsular shift (balance stability vs motion), insufficient rehabilitation (4-6 months for capsular healing), and operating on voluntary dislocators (psychological issues first). Patient selection is critical.

Quick Decision Guide: MDI vs Unidirectional Instability

Mnemonic

AMBRIIAMBRII Criteria for MDI

Atraumatic

Onset without significant traumatic event, insidious symptoms

Multidirectional

Symptomatic instability in two or more directions (anterior, posterior, inferior)

Bilateral

Often affects both shoulders (50-80% bilateral involvement)

Rehabilitation

First-line treatment with structured physiotherapy (6-12 months trial)

Inferior capsular shift

Surgical option if conservative management fails after adequate trial

Interval closure

Rotator interval closure often required when sulcus positive in external rotation

Memory Hook:Remember AMBRII as the complete MDI story from diagnosis to treatment: starts Atraumatic and Multidirectional, often Bilateral, treat with Rehabilitation first, then Inferior capsular shift with Interval closure if needed.

Mnemonic

BEIGHTONBeighton Hypermobility Score (9 Points Total)

Beyond 90° at MCP

Passive dorsiflexion 5th MCP beyond 90° - 1 point per side (2 points total)

Elbow hyperextension

Elbow hyperextension beyond 10° - 1 point per side (2 points total)

Index flexibility

Passive thumb to forearm apposition - 1 point per side (2 points total)

Genu recurvatum

Knee hyperextension beyond 10° - 1 point per side (2 points total)

Hands flat on floor

Forward trunk flexion palms flat on floor, knees straight (1 point total)

Total of 9 points

Score ≥4/9 indicates generalized hypermobility

Outcomes affected

High Beighton score (≥6) associated with poorer surgical outcomes

Note bilaterally

Test all joints bilaterally except trunk flexion

Memory Hook:Remember the Beighton score tests peripheral joints first (fingers, thumbs - 4 points), then major joints (elbows, knees - 4 points), then trunk (1 point). Score of 4 or more means generalized hypermobility affecting treatment.

Mnemonic

SULCUSSulcus Sign Grading

Standard position

Patient seated or standing, arm at side in neutral rotation

Unload the shoulder

Apply inferior traction force to relaxed arm at wrist or elbow

Look for depression

Observe indentation below acromion as humeral head translates inferiorly

Compare to contralateral

Always compare degree of translation to opposite shoulder

Use grading system

Grade I under 1cm, Grade II 1-2cm, Grade III greater than 2cm

Second test in ER

Repeat test with arm in external rotation - positive suggests rotator interval pathology

Memory Hook:Think SULCUS as the systematic approach to examining inferior instability: Standard position first, apply Unload force, Look for depression, Compare sides, Use grading, and crucial Second test in external rotation to assess rotator interval.

Mnemonic

FAILEDIndications for Surgical Intervention in MDI

Failed rehabilitation

Minimum 6 months structured physiotherapy without symptom improvement

Adequate compliance

Patient compliant with therapy but persistent symptoms despite proper execution

Inability to function

Significant functional limitation affecting work, sport, or activities of daily living

Lifestyle compromised

Patient unable to participate in desired activities due to instability

Examination confirms structural

Structural MDI (Stanmore Type I or III), not voluntary or muscle patterning

Documented objective instability

Positive sulcus sign, load-and-shift Grade 2-3, examination under anesthesia confirms

Memory Hook:Remember patient has FAILED when ready for surgery: proper rehabilitation Failed, patient shows Adequate compliance, has Inability to function, Lifestyle is compromised, Examination confirms structural pathology, and there is Documented objective instability on examination.

Overview and Epidemiology

Definition

Multidirectional instability (MDI) is defined as symptomatic glenohumeral instability in two or more directions (anterior, posterior, and/or inferior) occurring without significant trauma. The hallmark is inferior laxity demonstrated by a positive sulcus sign, distinguishing it from unidirectional instability patterns.

MDI represents a spectrum of capsular redundancy and muscular insufficiency, ranging from generalized connective tissue disorders to acquired capsular stretch. The key diagnostic criteria include atraumatic onset, instability in multiple directions, and characteristic examination findings of inferior translation.

Exam Pearl

The critical distinction between MDI and unidirectional instability is not just the number of directions of instability, but the underlying pathology: MDI involves global capsular redundancy and often generalized ligamentous laxity, whereas unidirectional instability typically results from specific traumatic labral and capsular injury. This fundamental difference drives completely different treatment algorithms.

Epidemiology

MDI predominantly affects adolescents and young adults, with peak incidence between 15 and 25 years of age. There is a female predominance with a 2:1 ratio compared to males, likely related to higher baseline ligamentous laxity and hormonal influences on connective tissue.

Bilateral involvement occurs in 50-80% of patients, reflecting the systemic nature of capsular laxity in many cases. Approximately 30-40% of MDI patients demonstrate generalized joint hypermobility with Beighton scores of 4 or greater, indicating underlying connective tissue disorder.

Sport participation, particularly overhead activities (swimming, gymnastics, volleyball), is common in the history. However, unlike traumatic instability, there is no identifiable injury event. Symptoms develop insidiously with repetitive overhead use causing progressive capsular stretch.

Risk Factors

Intrinsic factors include generalized joint hypermobility (Beighton score ≥4), connective tissue disorders (Ehlers-Danlos syndrome, Marfan syndrome), family history of hypermobility, and female gender. These constitutional factors predispose to global capsular laxity.

Extrinsic factors include repetitive overhead activities (swimming, gymnastics, throwing sports), improper training techniques leading to capsular stretch, delayed muscle maturation in adolescents, and poor scapular mechanics causing secondary glenohumeral instability.

Screen all adolescent patients with shoulder pain for signs of MDI, even without instability symptoms. Early identification allows preventive rehabilitation to strengthen dynamic stabilizers before symptomatic instability develops. Bilateral examination is mandatory as contralateral involvement may be subclinical.

The combination of constitutional laxity and repetitive overhead loading creates a cumulative capsular stretch pattern. Athletes with generalized hypermobility are particularly vulnerable to developing symptomatic MDI when participating in overhead sports without adequate rotator cuff and scapular strengthening.

Pathophysiology and Mechanisms

Glenohumeral Joint Anatomy

The glenohumeral joint is inherently unstable, relying on both static and dynamic stabilizers to maintain congruity. The bony anatomy provides minimal constraint, with the humeral head being three times larger than the shallow glenoid fossa. This design allows extensive range of motion but depends on soft tissue integrity.

Static stabilizers include the glenoid labrum (deepens socket by 50%), glenohumeral ligaments (anterior band of IGHL most important), joint capsule (provides volume constraint), and negative intra-articular pressure. The inferior glenohumeral ligament complex (IGHL) is the primary restraint to anterior and posterior translation with the arm in abduction and external rotation.

Dynamic stabilizers include the rotator cuff muscles (compressive force creates concavity-compression effect), long head of biceps (superior stability), scapular stabilizers (maintain glenoid position), and proprioceptive neuromuscular control. The rotator cuff provides approximately 50% of shoulder stability through concavity-compression mechanism.

The rotator interval is the space between the supraspinatus and subscapularis tendons, bounded by the coracoid process medially and the bicipital groove laterally. This interval contains the coracohumeral ligament and superior glenohumeral ligament, which are primary restraints to inferior translation, particularly with the arm in adduction and external rotation.

Pathophysiology of MDI

MDI develops when capsular volume exceeds the normal capacity to constrain the humeral head within the glenoid. The primary pathology is global capsular redundancy, particularly affecting the inferior capsular pouch and rotator interval. This allows excessive translation in multiple directions.

The inferior glenohumeral ligament complex becomes attenuated and stretched, losing its normal restraint function. The capsular volume increase is most pronounced in the inferior and posterior aspects, explaining the characteristic positive sulcus sign and posterior instability component in MDI.

Rotator interval pathology is present in most MDI cases, manifested by persistent positive sulcus sign even when the arm is held in external rotation. The coracohumeral ligament and superior glenohumeral ligament become elongated, allowing excessive inferior translation that is not constrained by rotation.

The glenoid labrum in MDI is typically attenuated or absent rather than torn, reflecting the congenital or developmental nature rather than traumatic etiology. There is no discrete Bankart lesion as seen in traumatic anterior instability, although secondary labral fraying may occur with chronic instability.

Exam Pearl

The key pathoanatomic difference between MDI and traumatic instability: MDI involves global capsular volume increase with attenuated labrum, while traumatic instability has specific focal capsulolabral injury (Bankart lesion) with normal capsular volume elsewhere. This explains why Bankart repair alone fails in MDI - the underlying capsular redundancy remains unaddressed.

Biomechanical Consequences

The enlarged capsular volume disrupts the normal concavity-compression mechanism. With excessive laxity, the humeral head cannot maintain centered position in the glenoid despite rotator cuff contraction. Translation occurs despite intact dynamic stabilizers, leading to symptomatic instability.

Inferior capsular redundancy creates a "hammock effect" where the inferior pouch allows the humeral head to sag inferiorly with the arm at the side. This manifests as the positive sulcus sign and explains inferior subluxation symptoms. The stretched capsule cannot be tensioned by muscle contraction alone.

Scapular dyskinesis commonly develops secondary to MDI as the scapular stabilizers attempt to compensate for glenohumeral instability. The scapula protracts and tilts anteriorly, further compromising the glenoid position and exacerbating the instability pattern. This creates a vicious cycle of progressive dysfunction.

Proprioceptive deficits occur as mechanoreceptors in the stretched capsule fail to provide accurate position sense. Patients lose normal neuromuscular control patterns, leading to aberrant muscle activation sequences. This contributes to persistent symptoms even when capsular volume is surgically reduced.

Stanmore Triangle Concept

The Stanmore classification recognizes three distinct MDI phenotypes based on underlying pathology:

Type I (Traumatic, Structural) occurs when significant trauma causes capsular disruption in a previously normal shoulder. The capsular injury creates structural laxity allowing multidirectional instability. These patients have clear injury history and structural findings on imaging.

Type II (Atraumatic, Structural) represents the classic MDI patient with constitutional capsular laxity, often associated with generalized hypermobility. There is no trauma history, and symptoms develop insidiously. These patients have global capsular redundancy and often bilateral involvement.

Type III (Atraumatic, Non-Structural, Muscle Patterning) involves psychological factors and voluntary muscle inhibition causing instability. The capsule may be normal volume, but aberrant neuromuscular control allows symptomatic translation. These patients often have voluntary control of their instability.

Identifying the Stanmore type is critical for treatment planning. Type I and II (structural) may benefit from capsular shift if rehabilitation fails. Type III (non-structural, muscle patterning) rarely benefits from surgery and may require psychiatric evaluation. Operating on Type III patients leads to poor outcomes and potential psychiatric complications.

Understanding these distinct pathophysiologic mechanisms guides appropriate treatment selection and prognostication in MDI patients.

Classification Systems

The Stanmore Triangle classification, developed by Lewis et al., categorizes shoulder instability based on etiology and underlying pathology. This classification is particularly valuable for MDI as it distinguishes structural from non-structural causes, which have completely different treatment implications.

Type I: Traumatic, Structural

Characteristics:

Significant traumatic event causing capsular injury
Structural damage on imaging (capsular tears, labral injury)
Unidirectional or multidirectional depending on injury pattern
Apprehension positive in direction of trauma
Normal generalized joint laxity (normal Beighton score)

Management: These patients may require surgery if conservative management fails. Structural repair of the specific capsulolabral injury is appropriate.

Type II: Atraumatic, Structural

Characteristics:

No significant trauma history
Constitutional capsular laxity and redundancy
Often generalized hypermobility (Beighton ≥4)
Bilateral involvement in 50-80%
Positive sulcus sign pathognomonic
Insidious onset of symptoms

Management: Rehabilitation first-line with 80-90% success. Surgery (inferior capsular shift) only after minimum 6 months failed conservative treatment.

Type III: Atraumatic, Non-Structural, Muscle Patterning

Characteristics:

No structural pathology on examination or imaging
Voluntary component to instability
Psychological factors often present
May have secondary gain from symptoms
Normal capsular volume on examination under anesthesia
Aberrant neuromuscular control patterns

Management: Physiotherapy focusing on motor control and neuromuscular retraining. Psychiatric evaluation may be required. Surgery contraindicated as underlying pathology is not structural.

Exam Pearl

The Stanmore classification is essential for surgical decision-making. Type I and II have structural pathology amenable to surgical correction if rehabilitation fails. Type III patients have normal anatomy with muscle patterning dysfunction - surgery will fail and may worsen psychological issues. Always document which Stanmore type when assessing MDI patients.

This classification emphasizes that "MDI" is not a single entity but encompasses different pathologies requiring individualized treatment approaches based on underlying mechanism.

Clinical Assessment

History

Presenting Symptoms

Instability symptoms are the hallmark complaint. Patients describe shoulder "slipping," "going out," or "feeling loose" with specific activities. Unlike traumatic instability, there is typically no fear or apprehension, but rather a sensation of looseness or inability to control the shoulder position.

Symptoms occur with overhead activities (reaching, throwing, swimming) and arm positions that stress the capsule (abduction and external rotation, forward flexion). Patients may report multiple direction symptoms: anterior with external rotation, posterior with internal rotation and horizontal adduction, inferior with traction or carrying loads.

Pain is often present but secondary to instability rather than primary complaint. Pain location is typically diffuse shoulder region rather than focal. It occurs during or after activities involving instability episodes. Some patients describe a "dead arm" sensation with overhead activities.

Functional limitations include difficulty with overhead sports, inability to carry heavy objects, trouble sleeping on affected shoulder, and avoidance of positions that provoke instability. Swimming is classically difficult due to repetitive overhead loading in multiple planes.

Key History Questions

Onset: "Did you have a specific injury?" (MDI is atraumatic). "When did symptoms start?" (insidious onset over months). "Which activities make it worse?" (overhead, carrying loads).

Directions: "In what positions does your shoulder feel loose?" "Can you demonstrate the positions that cause problems?" "Does it slip forward, backward, or downward?" (document all directions).

Voluntary component: "Can you make your shoulder slip out on purpose?" "Do you ever demonstrate this to others?" (positive suggests Stanmore Type III, non-structural).

Bilateral involvement: "Does your other shoulder have similar problems?" "Do you have looseness in other joints?" (elbows, knees, fingers).

Previous treatment: "Have you tried physiotherapy?" "For how long and how many sessions?" "What exercises were prescribed?" (document adequacy of conservative trial).

Impact: "What activities can you no longer do?" "How does this affect your work, sport, daily life?" (functional impact assessment).

Red Flags in History

Voluntary dislocation with secondary gain suggests psychological component (Stanmore Type III). These patients demonstrate instability to others, may have psychiatric comorbidity, and rarely benefit from surgery.

Acute traumatic onset suggests unidirectional traumatic instability rather than true MDI. Presence of significant trauma should prompt search for labral injury and reconsideration of MDI diagnosis.

Unilateral symptoms only in patient without generalized laxity raises question of true MDI versus microtraumatic unidirectional instability. Bilateral examination may reveal subclinical contralateral involvement.

Always screen for generalized hypermobility syndromes (Ehlers-Danlos, Marfan) by asking about joint hyperextensibility, skin hyperelasticity, easy bruising, and family history. These connective tissue disorders have systemic implications beyond shoulder instability and require specialized management.

A thorough history establishes the atraumatic multidirectional nature of symptoms and excludes voluntary component before proceeding with examination and imaging.

Physical Examination

Inspection

Standing posture: Observe scapular position from behind. Look for winging, protraction, or asymmetry suggesting scapular dyskinesis. MDI patients commonly demonstrate inferior angle prominence and protracted scapular posture.

Muscle atrophy: Note any atrophy of rotator cuff (supraspinatus, infraspinatus fossae) or deltoid suggesting chronic dysfunction or neurologic involvement. Generalized muscle underdevelopment common in adolescent MDI patients.

Shoulder symmetry: Compare heights of shoulders. Inferior subluxation may cause affected shoulder to appear lower. Measure with patient standing relaxed, arms at sides.

Generalized hypermobility screening: Observe for genu recurvatum (knee hyperextension), elbow hyperextension, or other stigmata of hypermobility while patient standing.

Palpation

Bony landmarks: Palpate AC joint (exclude AC pathology), coracoid process (evaluate for tenderness), and humeral head position (may be subluxed inferiorly even at rest).

Rotator cuff: Palpate greater tuberosity and supraspinatus/infraspinatus tendons. Tenderness suggests secondary rotator cuff pathology from chronic instability.

Scapular stabilizers: Palpate rhomboids, serratus anterior, trapezius for tenderness or trigger points. Scapular dyskinesis creates muscular overload patterns.

Range of Motion

Active ROM: Assess forward flexion, abduction, internal/external rotation in neutral and 90-degree abduction. MDI patients typically have full or even excessive ROM.

Passive ROM: Often exceeds normal limits due to capsular laxity. May have greater than 90 degrees external rotation at 90 degrees abduction. Compare bilaterally.

Rotational ROM at 90 degrees abduction: External rotation greater than 110 degrees suggests anterior capsular laxity. Internal rotation with thumb reaching contralateral scapula suggests posterior laxity.

Specific MDI Tests

Sulcus sign: MANDATORY test for MDI diagnosis. Perform with arm in neutral rotation and again in external rotation. Grade I less than 1cm, Grade II 1-2cm, Grade III greater than 2cm. Document whether sulcus persists in external rotation (indicates rotator interval incompetence).

Load-and-shift: Patient supine, shoulder at table edge. Stabilize scapula, load humeral head into glenoid, then apply anterior and posterior translation force. Grade 0-3 scale (see classification section). Test in multiple abduction angles.

Hyperabduction test: Passively abduct arm overhead. Normal maximum abduction approximately 180 degrees. MDI patients may achieve greater than 180 degrees with inferior subluxation of humeral head.

Anterior apprehension: Usually NEGATIVE in pure MDI (distinguishes from traumatic anterior instability). Position arm in 90 degrees abduction and progressive external rotation. No fear response typical.

Posterior stress test: Forward flex shoulder to 90 degrees, internally rotate, and apply posterior directed force on elbow. Posterior subluxation occurs in MDI but without apprehension.

Jobe relocation test: Usually negative in MDI as no anterior apprehension to relieve. Positive relocation suggests anterior labral pathology and traumatic component.

Beighton Hypermobility Score

Systematically assess all 9 Beighton criteria. Score of 4 or greater indicates generalized joint hypermobility. Document score in all MDI patients as it affects prognosis and surgical outcomes.

Exam Pearl

The "push-pull test" is highly specific for MDI: stabilize scapula with one hand, grasp proximal humerus with other hand, and alternately push posterior then pull anterior while feeling for excessive translation. Grade 2-3 translation in BOTH directions confirms multidirectional laxity. Compare to contralateral shoulder.

Complete bilateral examination is mandatory. Subclinical contralateral involvement common and affects diagnosis of bilateral MDI requiring modified treatment approach.

Examination Under Anesthesia

Examination under anesthesia (EUA) is routinely performed immediately before surgical intervention for MDI to quantify the true degree of instability without muscle guarding and to confirm the diagnosis.

Indications for EUA

Preoperative assessment: Performed in operating room immediately before arthroscopy or open stabilization to confirm MDI diagnosis and plan surgical strategy.

Quantify instability: Eliminate voluntary muscle control and guarding to reveal true capsular laxity. Distinguish structural laxity from muscle patterning dysfunction.

Bilateral comparison: EUA of both shoulders (even if only one symptomatic) provides true baseline for comparison and may reveal subclinical bilateral involvement.

Surgical planning: Degree of laxity on EUA determines extent of capsular shift required and need for rotator interval closure.

EUA Technique

Positioning: Patient supine with shoulder at table edge. Complete muscle relaxation confirmed with anesthesiologist.

Systematic assessment: Perform load-and-shift in anterior and posterior directions at 0, 45, and 90 degrees of abduction. Grade translation on 0-3 scale at each position.

Sulcus sign: Apply inferior traction with arm in neutral rotation, then repeat in external rotation. Measure depth of sulcus and document whether it persists in external rotation.

Hyperabduction: Passively abduct arm and note degree of hyperabduction possible before reaching bony block. Excessive hyperabduction (greater than 180 degrees) indicates inferior capsular redundancy.

Rotation at 90 degrees abduction: Measure maximum external rotation (normal approximately 90 degrees, MDI often greater than 110 degrees) and internal rotation.

Documentation Requirements

Grade of laxity: Document Grade 0-3 for anterior, posterior, and inferior directions. MDI diagnosis requires Grade 2 or 3 laxity in at least two directions.

Comparison to contralateral: Always examine contralateral shoulder. Some patients have bilateral Grade 2 laxity but only unilateral symptoms - this remains MDI requiring bilateral awareness.

Rotator interval assessment: Specifically document whether sulcus persists in external rotation, indicating rotator interval incompetence requiring surgical closure.

Reducibility: Note whether instability is easily reducible or whether humeral head locks out over glenoid (latter suggests more severe pathology).

Clinical Significance

EUA findings guide surgical decision-making. Grade 3 laxity in multiple directions indicates need for extensive capsular shift. Persistent sulcus in external rotation mandates rotator interval closure. Bilateral Grade 2 laxity may indicate need for eventual contralateral surgery.

If EUA reveals only Grade 1 laxity or laxity in single direction only, reconsider MDI diagnosis. Patient may have Stanmore Type III (muscle patterning) disorder where muscle relaxation eliminates the instability, or may have unidirectional instability misdiagnosed as MDI. EUA that does not confirm clinical findings should prompt abandoning planned surgery and reassessment.

EUA provides objective quantification of instability severity, confirms MDI diagnosis, and is essential for appropriate surgical planning when conservative management has failed.

Special Tests Summary

High-Yield Examination Maneuvers

Sulcus Sign (Sensitivity 90%, Specificity 85% for MDI):

Pathognomonic when Grade II-III
Must test in neutral AND external rotation
Persistent sulcus in ER indicates rotator interval pathology
Always compare bilaterally

Load-and-Shift (Sensitivity 85%, Specificity 80%):

Grade 2-3 in BOTH anterior and posterior confirms multidirectional
Test at multiple abduction angles
Must stabilize scapula and apply axial load first
Grade 3 (dislocation) highly specific for severe MDI

Hyperabduction Test (Sensitivity 70%, Specificity 90%):

Passive abduction greater than 180 degrees abnormal
Indicates inferior capsular pouch redundancy
Correlates with sulcus sign severity
Compare to contralateral side

Anterior Apprehension (Usually NEGATIVE in pure MDI):

Positive apprehension suggests traumatic component
Helps distinguish MDI from traumatic anterior instability
Absence of apprehension despite laxity characteristic of MDI
If positive, consider hybrid pathology

Gagey Hyperabduction Test:

Measure passive abduction with scapula stabilized
Normal less than 105 degrees
Greater than 105 degrees indicates inferior capsular laxity
Correlates with sulcus sign and need for inferior capsular shift

Examination Findings That Distinguish MDI

Positive for MDI:

Sulcus sign Grade II-III
Load-and-shift Grade 2-3 in multiple directions
Negative anterior apprehension despite laxity
Bilateral involvement
Beighton score 4 or greater
Excessive rotational ROM

Suggests alternative diagnosis:

Positive apprehension test (traumatic anterior instability)
Unidirectional laxity only (TUBS pattern)
Acute trauma history (traumatic instability)
Focal labral tenderness (labral tear)
Voluntary demonstration with secondary gain (Stanmore Type III)
Normal capsular laxity on EUA despite clinical symptoms (muscle patterning)

Exam Pearl

The "MDI triad" of examination findings: (1) Positive sulcus sign Grade II-III, (2) Load-and-shift Grade 2-3 in at least two directions, (3) Negative anterior apprehension test. Presence of all three findings is highly specific for MDI and distinguishes from unidirectional traumatic instability.

Systematic bilateral examination using these validated maneuvers establishes MDI diagnosis with high confidence and guides treatment planning.

Investigations

Radiographic Assessment

Standard views: AP in internal and external rotation, axillary lateral, scapular Y view. Radiographs in MDI are typically NORMAL, which helps distinguish from traumatic instability with bony injury.

Findings to exclude: Hill-Sachs lesion (suggests traumatic anterior dislocation), bony Bankart (anterior glenoid fracture), reverse Hill-Sachs and posterior glenoid fracture (posterior dislocation), os acromiale, degenerative changes.

Stress radiographs: Not routinely performed for MDI. Weighted radiographs showing inferior subluxation are of historical interest only and not required for diagnosis.

Advanced Imaging Indications

MRI arthrogram: Not routinely required for MDI diagnosis (clinical diagnosis) but useful to exclude labral pathology if traumatic component suspected or if considering surgery.

Standard MRI: May show capsular redundancy and patulous capsule, but findings subtle. Cannot reliably quantify capsular volume. Useful to exclude rotator cuff pathology if clinical concern.

CT arthrogram: No role in MDI assessment unless bony pathology suspected. Does not assess capsular volume adequately.

Exam Pearl

MDI is a CLINICAL diagnosis based on history and examination. Imaging is primarily to EXCLUDE other pathology rather than to confirm MDI. Normal radiographs and MRI in a patient with positive sulcus sign and multidirectional laxity on examination confirms MDI diagnosis. Do not over-image these patients.

The role of imaging in MDI is limited compared to traumatic instability where imaging defines the structural pathology requiring surgical repair.

Management Algorithm

Clinical Algorithm— MDI Treatment Algorithm

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Conservative Management Details

The Burkhead-Rockwood rehabilitation protocol is the gold standard for MDI conservative treatment, with 80-90% success rate when properly executed with patient compliance.

Phase 1 (Weeks 0-6): Rotator cuff strengthening

Internal rotation strengthening (subscapularis)
External rotation strengthening (infraspinatus, teres minor)
Deltoid strengthening (anterior, middle, posterior)
Avoid provocative positions during strengthening
Low resistance, high repetition protocol

Phase 2 (Weeks 6-12): Scapular stabilization

Serratus anterior strengthening (wall slides, protraction exercises)
Rhomboid and middle trapezius (rows, scapular retraction)
Lower trapezius strengthening (prone Y exercises)
Scapular control exercises with shoulder motion
Integration of scapular and rotator cuff activation

Phase 3 (Weeks 12-24): Proprioception and neuromuscular control

Closed chain exercises (wall push-ups, quadruped exercises)
Proprioceptive training (unstable surfaces, perturbation)
Plyometric exercises progression
Dynamic stabilization drills
Sport-specific movement patterns

Phase 4 (Weeks 24+): Return to activity

Gradual return to overhead activities
Sport-specific training and conditioning
Maintenance program development
Ongoing strengthening and proprioception
Lifelong compliance required

Exam Pearl

The critical success factors for rehabilitation in MDI are: (1) Minimum 6 months duration before declaring failure, (2) Proper progression through all four phases without skipping steps, (3) Patient compliance with home exercise program, (4) Avoidance of provocative positions during strengthening phase, and (5) Lifelong maintenance program after return to activity. Rehabilitation "failure" is often inadequate trial rather than true biological failure.

This completes the conservative management protocol.

Surgical Technique

Arthroscopic capsular plication has become increasingly popular for MDI treatment, offering reduced morbidity compared to open techniques. However, outcomes are inferior to open inferior capsular shift, particularly in severe MDI.

Indications

Ideal candidates:

Young patients with lower functional demands
Grade 2 laxity (Grade 3 better suited to open)
Failed appropriate rehabilitation trial
Stanmore Type II (atraumatic structural)
Realistic expectations about success rates

Relative contraindications:

Grade 3 laxity in multiple directions
High-level athletes requiring return to contact sport
Revision surgery after failed previous stabilization
Generalized hypermobility with Beighton greater than 6
Significant voluntary component

Patient Positioning

Beach chair position: 30-45 degrees upright, head secured in neutral position. Affected arm free to move through full ROM. Table articulation allows position changes during procedure.

Lateral decubitus: Alternative positioning with arm in traction (10 pounds). Provides better visualization of inferior capsule but less physiologic for assessment.

Portal Placement

Posterior portal: Standard viewing portal, 2cm inferior and 1cm medial to posterolateral acromion. Establishes first for orientation.

Anterior superior portal: Just anterior to biceps tendon at rotator interval. Working portal for superior and rotator interval plication.

Mid-anterior portal: Through rotator interval or just superior to subscapularis. Working portal for anterior capsular plication.

Anterior inferior portal: 5:30 position (right shoulder) at inferior glenoid margin. Allows access to inferior capsular pouch.

Accessory posterior portal (Wilmington): Posterolateral, just lateral to standard posterior portal. Allows better access to posterior capsule for plication.

Arthroscopic Assessment

Systematic evaluation:

Drive-through sign: excessive capsular laxity allows scope to pass from posterior to anterior without resistance
Inferior pouch redundancy: visualize from anterior portal, note excessive volume
Rotator interval patulous: widened space between supraspinatus and subscapularis
Labral appearance: typically attenuated or absent, not torn
Cartilage evaluation: exclude chondral injury

Capsular Plication Technique

Inferior capsular plication:

Anterior inferior portal for suture passage
Multiple horizontal mattress sutures (PDS or FiberWire)
Plicate inferior capsule in anterior-to-posterior direction
3-5 sutures typically required
Reduce inferior pouch volume significantly
Avoid over-tensioning (loss of motion)

Posterior capsular plication:

Wilmington portal for suture management
Plicate posterior capsule from inferior to superior
Address posterior laxity component
2-3 sutures typically sufficient
Check external rotation ROM after plication

Rotator interval closure:

MANDATORY if sulcus persists in external rotation on EUA
Close interval between supraspinatus and subscapularis
Suture coracohumeral ligament to superior glenohumeral ligament
Obliterate the interval space
Eliminates inferior translation in external rotation

Key Technical Points

Suture management: Use suture shuttling techniques to pass sutures through capsule. Multiple devices available (suture lasso, penetrator, bird beak). Ensure adequate tissue purchase with each pass.

Tension adjustment: Plicate until drive-through sign eliminated but preserve ROM. Check ROM intraoperatively after each plication. Over-tensioning causes stiffness.

Anatomic landmarks: Identify axillary nerve inferiorly (risk with inferior plication). Stay anterior to mid-glenoid line. Visualize all sutures before tying.

Knot tying: Arthroscopic knot tying or knotless anchor techniques. Ensure knots well-seated and secure. Typical knots: SMC, Duncan loop.

The axillary nerve is at risk during inferior capsular plication. It courses along the inferior capsule approximately 1-2cm from the inferior glenoid margin. Stay superior to the 6 o'clock position on the glenoid face. Never pass sutures blindly in the inferior capsule. Direct visualization essential to avoid nerve injury.

Intraoperative Assessment

ROM testing: After plication, assess ROM before closing. Should maintain 140 degrees forward flexion, 40 degrees external rotation at side, and 60 degrees external rotation at 90 degrees abduction. Restricted motion requires suture release.

Stability testing: Load-and-shift should demonstrate Grade 0-1 translation. Complete elimination of laxity not goal (causes stiffness). Goal is Grade 0-1 with preserved motion.

Drive-through sign: Should be eliminated or significantly reduced. Inability to pass scope from posterior to anterior indicates adequate volume reduction.

Outcomes

Success rates for arthroscopic capsulorrhaphy in MDI range from 70-85%, lower than the 85-90% for open inferior capsular shift. Recurrence rates higher in patients with severe laxity, generalized hypermobility, and high-demand activities.

Patient satisfaction correlates with appropriate expectations and understanding that some residual laxity may persist. Return to sport rates approximately 80% at pre-injury level, achieved at 6-9 months postoperatively.

Complications

Stiffness is the most common complication after MDI surgery, occurring in 10-20% of patients. The risk is inherent when tightening a lax capsule - balancing stability and motion preservation is challenging.

Risk Factors

Patient factors:

Tendency toward stiffness (previous adhesive capsulitis)
Diabetes mellitus (higher stiffness risk)
Female gender (higher baseline stiffness rates)
Age over 40 years
Underlying connective tissue disorder

Surgical factors:

Over-tensioning capsular shift
Aggressive rotator interval closure
Combined anterior and posterior procedures
Thermal capsulorrhaphy (historical)
Inadequate intraoperative ROM assessment

Postoperative factors:

Prolonged immobilization (greater than 6 weeks)
Non-compliance with rehabilitation
Delayed initiation of ROM exercises
Pain limiting rehabilitation participation

Clinical Presentation

Patients report restricted shoulder motion affecting activities of daily living. Forward flexion limited (less than 120 degrees), external rotation limited (less than 30 degrees), internal rotation limited (unable to reach back).

Pain with end-range motion is common. Patients describe feeling "tight" and "restricted." Night pain may occur due to capsular inflammation. Quality of life significantly impacted.

Prevention Strategies

Intraoperative ROM assessment: After capsular shift, assess ROM before final closure. Release sutures if motion inadequate (less than 140 degrees elevation, less than 40 degrees ER).

Appropriate tensioning: Goal is reducing laxity to Grade 0-1, not complete elimination. Some laxity preservation necessary for motion. Avoid over-tensioning.

Limited immobilization: Modern protocols use 4-6 weeks immobilization rather than historical 8 weeks. Balance healing with motion preservation.

Early passive ROM: Initiate gentle passive ROM at 6 weeks. Avoid delay beyond 6 weeks as stiffness risk increases significantly.

Patient education: Counsel regarding stiffness risk and importance of rehabilitation compliance. Prepare patients for potentially slow ROM recovery.

Treatment

Conservative management (first-line):

Intensive physiotherapy with passive stretching
Heat application before stretching
Joint mobilization techniques
NSAIDs for pain and inflammation
Home exercise program compliance
Duration: 3-6 months minimum trial

Manipulation under anesthesia:

Indicated if conservative fails after 3-6 months
Performed at 4-6 months postoperatively (allow healing)
Gentle manipulation to restore ROM
Risk of capsular re-injury and recurrent instability
Followed by intensive physiotherapy

Arthroscopic capsular release:

Reserved for refractory cases failing manipulation
Selective release of contracted capsule and adhesions
Risk of destabilizing previous stabilization
Requires experienced surgeon
Success rate 70-80% for ROM improvement

Exam Pearl

The key to preventing stiffness after MDI surgery is intraoperative ROM assessment. Before final closure, test ROM in all planes. Target minimum ROM: 140 degrees forward flexion, 40 degrees ER at side, 60 degrees ER at 90 degrees abduction. If these minimums not achieved, release capsular sutures until adequate motion restored. Accepting some residual laxity preferable to creating stiffness.

Stiffness remains a challenging complication requiring prolonged rehabilitation and potentially additional intervention to restore function.

Rehabilitation and Postoperative Care

Postoperative Protocol

MDI surgery requires prolonged protection compared to traumatic instability repair due to need for capsular healing in tensioned position. Premature mobilization risks capsular stretch-out and recurrent instability.

Phase 1: Protection (Weeks 0-6)

Immobilization: Shoulder immobilized in sling with arm at side in neutral rotation. Remove for hygiene only. Sleep in sling. Strict compliance essential.

Goals: Protect capsular repair, allow initial healing, prevent capsular stretch, minimize pain and inflammation.

Allowed activities:

Hand, wrist, elbow ROM exercises
Grip strengthening
Pendulum exercises (controversial, some surgeons avoid)
Scapular isometrics without shoulder motion

Prohibited activities:

Active shoulder ROM
Passive shoulder ROM
Resisted shoulder exercises
Lifting objects
Reaching or overhead activities
Sleeping on operative side

Pain management: Oral analgesics, ice application, NSAIDs (after first 6 weeks to avoid healing impairment).

Phase 2: Early Motion (Weeks 6-12)

Immobilization: Discontinue sling at 6 weeks. Gradual weaning if stiffness concern.

Goals: Restore passive ROM, begin active-assisted ROM, protect capsular repair integrity, avoid stretching repaired capsule.

Passive ROM exercises:

Forward flexion to 90 degrees (weeks 6-8), progress to 120 degrees (weeks 8-10), then 140 degrees (weeks 10-12)
External rotation in scapular plane to 20 degrees (weeks 6-8), progress to 30 degrees (weeks 8-10), then 40 degrees (weeks 10-12)
Internal rotation to neutral (weeks 6-8), progress to 40 degrees (weeks 8-12)
Therapist-assisted stretching, avoid patient forcing motion

Active-assisted ROM: Begin at week 8 with table slides, wand exercises, pulley-assisted elevation. Patient assists with motion but does not force.

Prohibited activities:

Resisted strengthening
Aggressive stretching
Overhead reaching
Lifting greater than 5 pounds
Return to sport activities

Phase 3: Strengthening (Weeks 12-24)

Goals: Restore full ROM, progressive strengthening, improve neuromuscular control, prepare for functional activities.

ROM progression: Achieve full forward flexion (160-180 degrees), external rotation 50-60 degrees at side, internal rotation to T8-T10 level. Gentle stretching if plateau.

Strengthening progression:

Weeks 12-16: Isometric rotator cuff, light resistance band (0.5-1 pound)
Weeks 16-20: Progressive resistance strengthening, increase to 2-3 pounds
Weeks 20-24: Functional strengthening patterns, sport-specific preparation

Scapular strengthening: Rows, scapular retraction, serratus anterior strengthening (wall slides, protraction), trapezius strengthening (shrugs, Y-T-W exercises).

Proprioceptive training: Closed chain exercises, rhythmic stabilization, perturbation training, unstable surface exercises.

Criteria for progression: Pain-free ROM, adequate strength (4/5 or better on manual muscle testing), no signs of instability, patient compliance demonstrated.

Phase 4: Return to Activity (Months 6-9)

Goals: Return to full activities including sport, maintain strength and ROM, establish maintenance program.

Sport-specific training: Progressive return to overhead activities. Interval throwing program for throwing athletes. Swimming progression for swimmers. Contact sport progression with protective padding.

Functional testing: Assess before clearing for full return:

Full pain-free ROM
Strength 85% of contralateral
Negative instability examination
Sport-specific functional tests passed
Psychological readiness

Maintenance program: Lifelong rotator cuff and scapular strengthening essential. MDI patients have inherent capsular laxity requiring ongoing dynamic stabilizer maintenance.

Return to sport timeline:

Non-contact sports: 6 months minimum
Contact sports: 9 months minimum
Overhead sports (baseball, volleyball): 9-12 months
Swimming: 6-9 months with gradual progression

Exam Pearl

The most common cause of failure after MDI surgery is premature progression through rehabilitation phases. The capsule requires 12-16 weeks to achieve adequate tensile strength after surgical shift. Pushing ROM or starting strengthening too early risks capsular stretch-out and recurrent instability. Patience during rehabilitation is as important as surgical technique for successful outcomes.

Rehabilitation After Arthroscopic vs Open

Arthroscopic capsulorrhaphy: May allow slightly faster progression due to less tissue disruption and subscapularis preservation. Some protocols advance to active ROM at week 4-6 rather than 6-8.

Open capsular shift: Requires protection of subscapularis repair. More conservative ROM progression. Emphasize external rotation limits to protect subscapularis tendon healing.

Red Flags During Rehabilitation

Recurrent instability symptoms: Patient reports looseness, subluxation sensation. Stop progression, reassess with surgeon, consider examination under anesthesia.

Progressive stiffness: Failure to regain ROM despite appropriate therapy. Consider more aggressive therapy, possible manipulation if no progress by month 4-6.

Persistent pain: Pain should gradually improve. Persistent or worsening pain suggests complication (infection, chondrolysis, nerve injury). Requires surgical reassessment.

Subscapularis failure: After open technique, weakness of internal rotation, positive belly-press test. MRI to assess tendon integrity, may require revision repair.

Close communication between surgeon, therapist, and patient throughout rehabilitation maximizes outcomes and identifies complications early.

Outcomes and Prognosis

Conservative Treatment Outcomes

Structured rehabilitation following the Burkhead-Rockwood protocol achieves 80-90% success rates in appropriately selected MDI patients who are compliant with the program. Success is defined as return to activities without functional limitation from instability.

Factors predicting rehabilitation success:

Patient age under 25 years (younger patients respond better)
Excellent compliance with therapy program
Lower Beighton score (less than 4, localized laxity)
Unilateral involvement (better than bilateral)
Stanmore Type II (atraumatic structural)
Willingness to modify provocative activities

Factors predicting rehabilitation failure:

Poor compliance with exercise program
Generalized hypermobility (Beighton greater than 6)
Bilateral severe involvement
Grade III sulcus sign with severe inferior laxity
Stanmore Type III (muscle patterning, needs different approach)
Unrealistic expectations about activity return

The key is adequate trial duration - minimum 6 months with excellent compliance required before declaring rehabilitation failure. Many apparent "failures" are actually inadequate trials with poor compliance.

Surgical Outcomes

Surgical success rates vary significantly based on technique, patient selection, and severity of pathology.

Open inferior capsular shift:

Success rate: 85-90% good to excellent outcomes
Recurrent instability: 10-15%
Return to sport: 80-85% at previous level
Time to return: 6-9 months minimum
Patient satisfaction: 85-90%

Arthroscopic capsulorrhaphy:

Success rate: 70-85% good to excellent outcomes
Recurrent instability: 15-25%
Return to sport: 75-80% at previous level
Time to return: 6-9 months minimum
Patient satisfaction: 75-85%

Factors predicting surgical success:

Appropriate patient selection (failed adequate conservative trial)
Stanmore Type I or II (structural pathology)
Lower Beighton score (less than 4)
Compliant patient willing to follow postoperative restrictions
Realistic expectations about outcomes and activity modification
Experienced surgeon with MDI surgical expertise

Factors predicting surgical failure:

Severe generalized hypermobility (Beighton greater than 7)
Stanmore Type III (muscle patterning) - should not operate
Voluntary component or secondary gain
Premature return to provocative activities
Inadequate capsular shift or technical errors
Missed rotator interval pathology

Exam Pearl

The critical determinant of outcome in MDI is patient selection. Success rates quoted above apply to properly selected patients - Stanmore Type I or II, failed adequate conservative trial, realistic expectations, compliant with restrictions. Operating on poorly selected patients (Stanmore Type III, inadequate rehabilitation trial, unrealistic expectations) leads to failure regardless of surgical technique quality.

Long-term Outcomes

Long-term studies (5-10 years) after MDI surgery show some deterioration compared to early results. Recurrence rates increase over time as capsular tissue gradually stretches, particularly in hypermobile patients.

5-year outcomes after open capsular shift:

80-85% maintain good to excellent results
15-20% develop recurrent symptoms (versus 10-15% at 2 years)
Most recurrences are mild and manageable conservatively
Patient satisfaction remains high (80-85%)
Stiffness resolves in most patients by 5 years

10-year outcomes:

75-80% maintain satisfactory results
20-25% have some recurrent laxity
Many patients adapt and remain functional despite some laxity
Revision surgery rates low (less than 10%)
Arthritis rates similar to general population

Functional Outcomes

Return to activity is a primary goal for most MDI patients, particularly young athletes. Realistic expectations are critical.

Return to overhead sports (swimming, volleyball, throwing):

75-80% return to pre-injury level after surgery
15-20% return at lower level (recreational versus competitive)
5-10% unable to return due to recurrent symptoms or fear
Average time to return: 9-12 months
Permanent activity modification often required

Return to contact sports (rugby, football, wrestling):

70-75% return to competitive level
Higher risk of recurrent injury with contact
May require protective equipment or bracing
Average time to return: 9-12 months
Some positions may be unsuitable (offensive line, etc.)

Return to work:

90-95% return to full work duties
Overhead occupations may require modification
Heavy manual labor often requires permanent restrictions
Average time to full duty: 4-6 months
Occupational therapy may assist with work modifications

Quality of Life Outcomes

Patient-reported outcome measures show significant improvement after both conservative and surgical treatment of MDI, though some residual symptoms common.

WOSI (Western Ontario Shoulder Instability Index):

Baseline MDI: average 40-50% of maximum score
Post-rehabilitation: improvement to 75-85%
Post-surgery: improvement to 80-90%
Plateau occurs at 12-24 months

ASES (American Shoulder and Elbow Surgeons) score:

Baseline MDI: average 50-60 points
Post-treatment: improvement to 80-90 points
Correlates with return to activities and satisfaction

Prognostic Factors Summary

Excellent prognosis (greater than 90% success):

Localized MDI without generalized hypermobility
Excellent rehabilitation compliance
Realistic expectations and activity modification acceptance
Stanmore Type II, younger age
Open surgical technique if surgery required

Good prognosis (80-90% success):

Mild generalized hypermobility (Beighton 4-6)
Good compliance with structured treatment
Unilateral involvement
Willingness to modify high-risk activities

Guarded prognosis (70-80% success):

Severe generalized hypermobility (Beighton greater than 6)
Bilateral involvement
High-demand overhead athlete
Revision surgery scenario
Arthroscopic technique in severe MDI

Poor prognosis (less than 50% success):

Stanmore Type III (muscle patterning) - surgery should not be performed
Voluntary dislocation with secondary gain
Unrealistic expectations refusing activity modification
Connective tissue disorder (Ehlers-Danlos, Marfan)
Multiple previous failed surgeries

Understanding these prognostic factors allows appropriate patient counseling and shared decision-making regarding treatment approach and expectations.

Evidence Base

Burkhead-Rockwood Rehabilitation Protocol for MDI

Level III

Key Findings:

80% success rate with structured rehabilitation in MDI patients
Minimum 6 months rehabilitation trial required before declaring failure
Four-phase protocol focusing on rotator cuff and scapular strengthening
Patients with generalized hypermobility (Beighton ≥4) had lower success rates (65%)
Bilateral involvement did not predict rehabilitation failure
Voluntary dislocators and secondary gain patients did not benefit from therapy

Clinical Implication: This landmark study established rehabilitation as first-line treatment for MDI, demonstrating that 80% of properly selected patients can avoid surgery with structured physiotherapy. The protocol developed remains the foundation of modern MDI conservative management. Key insight: adequate trial duration is 6 months minimum, and patient selection matters - voluntary dislocators should not undergo surgery.

Open Inferior Capsular Shift for MDI

Level IV

Key Findings:

Introduced T-capsulorrhaphy technique for MDI surgical treatment
40 patients with MDI followed average 4 years postoperatively
Good to excellent results in 90% of patients at final follow-up
Recurrent instability in 10% of patients despite adequate capsular shift
Stiffness occurred in 15% requiring aggressive physiotherapy
Patients with generalized laxity had higher recurrence rates (20%)

Clinical Implication: Neer's inferior capsular shift technique established the gold standard open surgical treatment for MDI that remains widely used today. The study demonstrated that surgical volume reduction of redundant capsule can effectively treat MDI refractory to rehabilitation. Important recognition that patients with generalized hypermobility have higher failure rates, informing modern patient counseling and expectations.

Arthroscopic vs Open Capsular Shift for MDI

Level III

Key Findings:

Compared arthroscopic capsulorrhaphy (52 patients) to historical open shift controls
Arthroscopic: 76% satisfactory outcomes at average 3.8 years follow-up
Open inferior capsular shift: 89% satisfactory outcomes at comparable follow-up
Recurrent instability: arthroscopic 20%, open 10%
Stiffness: arthroscopic 12%, open 18%
Return to sport: arthroscopic 74%, open 82%
Patients with Beighton ≥6 had 40% failure rate regardless of technique

Clinical Implication: This study established that arthroscopic capsulorrhaphy has lower success rates than open inferior capsular shift for MDI, with higher recurrence rates (20% vs 10%). However, arthroscopic approach has lower stiffness rates. Appropriate patient selection critical: mild to moderate MDI may be suitable for arthroscopic approach, while severe MDI with Grade 3 laxity better treated with open technique. Severe generalized hypermobility predicts poor outcomes regardless of technique.

Thermal Capsulorrhaphy Failure and Abandonment

Level III

Key Findings:

Reported devastating chondrolysis complication after thermal capsulorrhaphy
Both patients developed rapid glenohumeral arthritis within 12 months of surgery
Progressive pain, stiffness, and radiographic joint space narrowing
Subsequent reviews showed 1-5% chondrolysis rate after thermal treatment
Long-term failure rates of thermal capsulorrhaphy reached 50-70% by 5 years
Technique completely abandoned due to complications and poor durability

Clinical Implication: This study highlighted the devastating complications of thermal capsulorrhaphy, leading to complete abandonment of the technique. Critical lesson for orthopedic surgery: early promising results and technical ease led to widespread adoption before long-term outcomes were established. By the time high failure rates and chondrolysis became apparent, thousands of patients had been treated. Modern MDI surgery uses capsular plication (tissue preservation) rather than ablation, with no chondrolysis risk.

Stanmore Triangle Classification and Treatment Outcomes

Level IV

Key Findings:

Introduced Stanmore Triangle classification distinguishing structural from non-structural MDI
Type I (Traumatic Structural): 85% surgical success rate with appropriate repair
Type II (Atraumatic Structural): 80% rehabilitation success, 85% surgical success if rehab fails
Type III (Muscle Patterning): 5% surgical success rate, high complication rate
Psychiatric evaluation identified 70% of Type III patients had psychological comorbidity
Operating on Type III patients resulted in poor outcomes and patient dissatisfaction

Clinical Implication: The Stanmore classification provides critical framework for MDI patient stratification and treatment planning. Key insight: not all instability is structural - muscle patterning dysfunction (Type III) will not respond to surgery and may worsen with surgical intervention. Identifying voluntary component and psychological factors essential before proceeding with surgical treatment. This classification prevents inappropriate surgery in patients who will not benefit.

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

Bilateral MDI in Young Swimmer

EXAMINER

"A 17-year-old female competitive swimmer presents with bilateral shoulder pain and instability. She reports feeling her shoulders 'slip out' with overhead swimming strokes. No specific injury. On examination, she has a positive sulcus sign Grade III bilaterally, load-and-shift Grade 2 in anterior and posterior directions, and a Beighton score of 7/9. How would you manage this patient?"

EXCEPTIONAL ANSWER

**Initial Assessment and Diagnosis:** "This is a classic presentation of bilateral multidirectional shoulder instability in a young overhead athlete with generalized joint hypermobility. The key clinical features supporting MDI diagnosis are: atraumatic onset, bilateral symptoms, positive sulcus sign Grade III indicating severe inferior laxity, multidirectional laxity on load-and-shift testing, and high Beighton score of 7 indicating significant generalized hypermobility." "I would classify this as Stanmore Type II - atraumatic, structural instability with constitutional laxity. The bilateral involvement and high Beighton score indicate this is related to her underlying connective tissue laxity rather than sport-specific overuse." **Initial Management - Conservative Treatment:** "MDI is managed conservatively first-line. I would explain to this patient and her family that surgery is NOT the initial treatment. Structured rehabilitation has 80-90% success rate in properly selected and compliant patients." "I would refer her for physiotherapy implementing the Burkhead-Rockwood protocol. This is a structured 6-12 month program with four phases:" "Phase 1 focuses on rotator cuff strengthening in all planes - internal rotation for subscapularis, external rotation for infraspinatus and teres minor, and deltoid strengthening. The goal is to enhance the dynamic stabilizers to compensate for the capsular laxity." "Phase 2 emphasizes scapular stabilization - strengthening serratus anterior, rhomboids, and trapezius to provide a stable base for the glenohumeral joint." "Phase 3 adds proprioceptive and neuromuscular control training using closed-chain exercises, rhythmic stabilization, and perturbation training." "Phase 4 is sport-specific training with gradual return to swimming activities, focusing on proper stroke mechanics to minimize capsular stress." "I would counsel that this requires a minimum 6-month trial with excellent compliance before considering surgery. Given her age and bilateral involvement, the goal is to avoid surgery if possible." **Activity Modification:** "During rehabilitation, I would recommend modifying her swimming training. Reduce overhead volume temporarily, focus on technique rather than distance, avoid extreme ranges of motion particularly in abduction and external rotation. May need to take a break from competitive swimming during initial rehabilitation phase." **Addressing the Bilateral Nature:** "The bilateral involvement is important for several reasons. First, it confirms this is constitutional laxity rather than sport-specific overuse. Second, it means rehabilitation must address both shoulders even if one is more symptomatic. Third, it affects prognosis - bilateral involvement in a hypermobile patient suggests this may be a chronic management issue requiring lifelong strengthening maintenance." **If Conservative Management Fails:** "If she remains significantly symptomatic after a proper 6-month rehabilitation trial with documented compliance, I would consider surgical intervention. However, I would counsel carefully about realistic expectations given her young age, bilateral involvement, high Beighton score, and desire to return to overhead sport - all factors associated with higher failure rates." "Surgical options would include arthroscopic capsulorrhaphy or open inferior capsular shift. Given her severe Grade III sulcus sign and high Beighton score, I would favor open inferior capsular shift which has better outcomes in severe MDI compared to arthroscopic techniques (85-90% vs 70-75% success)." "The procedure would involve T-capsulorrhaphy to reduce the inferior capsular volume, along with rotator interval closure given the severe inferior laxity. I would perform examination under anesthesia first to confirm the degree of structural laxity - important to ensure this is truly structural rather than muscle patterning dysfunction." **Examiner Follow-up: Would you operate on both shoulders?** "Not simultaneously. I would address the more symptomatic shoulder first. If surgery is successful and she has persistent symptoms on the contralateral side despite ongoing rehabilitation, could consider staged bilateral surgery with at least 6 months interval." "However, I would strongly encourage maximizing conservative management for as long as possible given her age. The goal is to get her through her competitive swimming years with non-operative management if possible, as surgery may limit her ability to return to elite-level overhead sport." **Key Examination Points Demonstrated:** - Recognized classic MDI presentation - Correctly diagnosed Stanmore Type II - Emphasized conservative treatment first-line - Detailed knowledge of Burkhead-Rockwood protocol - Appropriate patient counseling about prognosis - Understood factors predicting poor surgical outcomes - Balanced approach to potential surgery if conservative fails

KEY POINTS TO SCORE

MDI diagnosis requires instability in 2+ directions

Stanmore Type II classification guides treatment

Conservative rehabilitation is FIRST-LINE (Burkhead-Rockwood protocol)

Minimum 6-month rehabilitation trial before surgery

COMMON TRAPS

✗Recommending surgery as first-line treatment

✗Not addressing bilateral involvement

✗Underestimating generalized hypermobility impact on outcomes

LIKELY FOLLOW-UPS

"Would you operate on both shoulders simultaneously?"

"What surgical technique would you use if conservative fails?"

"What is the role of rotator interval closure?"

VIVA SCENARIOChallenging

Recurrent Instability After Arthroscopic Capsulorrhaphy

EXAMINER

"A 24-year-old male patient underwent arthroscopic capsulorrhaphy for MDI 18 months ago. He now returns with recurrent instability symptoms. Examination shows Grade II sulcus sign and Grade 2 anterior and inferior laxity. MRI shows intact capsular plication but some capsular stretch. He is frustrated and wants revision surgery. How would you manage this recurrence?"

EXCEPTIONAL ANSWER

**Assessment of Recurrence:** "This patient has recurrent instability after arthroscopic capsulorrhaphy for MDI. Before discussing revision surgery, I need to understand several key factors: the adequacy of his initial rehabilitation, his compliance with postoperative restrictions, what activities precipitated recurrence, and whether his expectations are realistic." "I would specifically ask: Did he complete the full postoperative protocol including 6 weeks immobilization and gradual ROM progression? Did he return to overhead or contact activities too early? Was there a specific traumatic event causing recurrence, or gradual onset? What is his functional limitation now compared to before surgery?" **Diagnostic Workup:** "His examination shows Grade II sulcus and Grade 2 laxity - this is less severe than typical preoperative MDI which would be Grade III sulcus and Grade 2-3 laxity in multiple directions. So he actually has some residual benefit from his previous surgery, just incomplete correction." "The MRI showing intact plication with capsular stretch suggests biological failure - the capsular tissue has stretched out during the healing process rather than a technical failure of the repair. This is more common in patients with generalized hypermobility or those who returned to activities too early." "I would assess his Beighton score if not done previously. High Beighton score (≥6) indicates generalized hypermobility which is a risk factor for recurrence and predicts poorer outcomes from revision surgery." **Re-examining the Initial Diagnosis:** "Before proceeding with revision surgery, I need to reconsider the diagnosis. Some questions: Could this be Stanmore Type III (muscle patterning, voluntary) rather than Type II (structural)? Was the initial surgery even indicated?" "I would specifically ask if he can voluntarily sublux his shoulder, whether there is any secondary gain from continued symptoms, and assess for psychiatric comorbidity. Examination should look for voluntary component - can he demonstrate instability on command?" **Conservative Management Trial:** "Despite his frustration, I would recommend reinstituting a structured rehabilitation program before considering revision surgery. Here's why: First, revision surgery has lower success rates than primary surgery (70-80% vs 85-90%). Second, he still has some benefit from his previous surgery. Third, many recurrences can be managed successfully with renewed focus on dynamic stabilization." "I would refer him to physiotherapy with specific focus on rotator cuff and scapular strengthening. The program should be similar to the Burkhead-Rockwood protocol but adapted for post-surgical shoulder. Minimum 3-6 month trial before declaring failure." "I would also recommend activity modification - avoid provocative overhead positions, may need to permanently modify sport participation or occupation if these involve high-risk activities." **Patient Counseling About Revision Surgery:** "I would have a frank discussion about revision surgery outcomes. The success rate is approximately 70-80%, lower than his initial surgery. There is a 20-30% chance of continued symptoms even after revision. The recovery is longer and more difficult - typically 6-8 weeks immobilization versus 4-6 weeks for primary." "Risk factors for revision failure include: generalized hypermobility, young age with high activity demands, previous arthroscopic technique (versus open), and capsular stretch pattern rather than discrete failure." **If Proceeding with Revision Surgery:** "If he fails an adequate conservative trial and has significant functional limitation affecting his quality of life, I would consider revision surgery. However, I would modify the approach from his index procedure." "Since he previously had arthroscopic capsulorrhaphy which has now failed, I would recommend conversion to open inferior capsular shift. This provides more robust capsular volume reduction and has better outcomes in revision scenarios." "Before surgery, I would perform examination under anesthesia to quantify his true laxity without muscle guarding. This is critical - if he only has Grade 0-1 laxity under anesthesia despite clinical symptoms, this suggests muscle patterning dysfunction rather than structural laxity, and surgery will fail again." **Surgical Technique for Revision:** "The revision open inferior capsular shift would involve deltopectoral approach, subscapularis management (either split or tenotomy), and identification of the previous capsular plication which will be incorporated in scar tissue." "I would perform an extensive capsular shift using T-capsulorrhaphy or lateral-based shift technique to maximize volume reduction. The capsular tissue quality will be inferior to virgin tissue, so I would be more aggressive with the shift while monitoring ROM intraoperatively." "Rotator interval closure is mandatory if not performed at index surgery, particularly given his inferior laxity component." "Postoperative protocol would be conservative - 6-8 weeks strict immobilization, then very gradual ROM progression over 3-4 months before any strengthening." **Examiner Follow-up: What would you do if his EUA shows only Grade 1 laxity?** "This would indicate that his structural laxity is minimal and his symptoms are due to neuromuscular control dysfunction or muscle patterning - essentially Stanmore Type III pathology. In this scenario, I would abandon the planned revision surgery." "I would wake him up and have a discussion about the findings. Explain that his shoulder has adequate structural stability but the problem is neuromuscular control. Recommend intensive physiotherapy focusing on proprioception and neuromuscular training, possibly psychiatric evaluation if voluntary component suspected." "Operating in this scenario would be futile and potentially harmful - you cannot fix a neuromuscular control problem with capsular tightening." **Key Examination Points Demonstrated:** - Systematic approach to surgical failure - Recognized importance of reassessing diagnosis - Emphasized conservative management before revision - Realistic counseling about revision outcomes - Appropriate technique modification (arthroscopic to open) - Critical role of EUA before revision surgery - Understanding when NOT to operate

KEY POINTS TO SCORE

Reassess diagnosis - confirm Stanmore Type I or II

Conservative rehabilitation trial before revision

Revision surgery has lower success rates (70-80%)

Convert to open inferior capsular shift for revision

COMMON TRAPS

✗Rushing to revision surgery without adequate conservative trial

✗Not reassessing for Stanmore Type III (muscle patterning)

✗Using same arthroscopic technique for revision

LIKELY FOLLOW-UPS

"What would you do if EUA shows only Grade 1 laxity?"

"How does revision success rate compare to primary?"

"When would you abandon planned revision surgery?"

VIVA SCENARIOCritical

Thermal Capsulorrhaphy Failure and Complications

EXAMINER

"You are asked to assess the surgical video from a colleague who performed arthroscopic capsulorrhaphy for MDI. On the video, you see thermal energy being applied to the capsule in a 'shrinkage' pattern rather than suture plication. The patient is now 18 months post-op with recurrent instability and shoulder pain. What are your thoughts and how would you manage?"

EXCEPTIONAL ANSWER

**Initial Response to Scenario:** "This is a concerning scenario. The colleague appears to have performed thermal capsulorrhaphy, which was a technique popular in the late 1990s and early 2000s but has now been completely abandoned due to high failure rates and devastating complications, particularly glenohumeral chondrolysis." "My immediate concern for this patient 18 months post-thermal capsulorrhaphy is two-fold: recurrent instability due to capsular stretch-out, and potential chondrolysis which can present months to years after thermal treatment." **Understanding Thermal Capsulorrhaphy:** "Thermal capsulorrhaphy involved applying radiofrequency or laser energy to redundant capsule, causing collagen denaturation and immediate capsular shrinkage. It was attractive because it was technically easier than suture plication and showed immediate intraoperative tightening." "However, we now know this technique fails because the thermal injury causes capsular necrosis rather than healthy healing. The scar tissue that forms gradually elongates under physiologic stress, leading to recurrent laxity. Long-term studies showed failure rates of 50-70% by 5 years." "More devastating was the complication of glenohumeral chondrolysis - cartilage death from thermal energy causing rapid-onset arthritis in young patients. This occurred in 1-5% of patients and often required arthroplasty at young age." **Assessment of Current Patient:** "For this patient presenting 18 months post-thermal capsulorrhaphy with pain and instability, I need to determine: Is this recurrent instability alone, or is there chondrolysis developing?" "History would focus on: Is pain the predominant symptom or instability? Is pain progressive? Is there stiffness developing? Any crepitus or catching?" "Examination would assess for: Degree of instability (sulcus sign, load-and-shift grading), range of motion (chondrolysis causes progressive stiffness), crepitus suggesting chondral damage, pain with motion." "Imaging is critical: Standard radiographs to assess joint space (narrowing suggests chondrolysis). MRI to assess capsular integrity, identify recurrent laxity, and crucially to evaluate cartilage. MRI arthrogram or high-resolution MRI with cartilage sequences to detect early chondrolysis before radiographic changes appear." **If Chondrolysis is Present:** "If imaging shows evidence of chondrolysis with cartilage loss, this is a devastating diagnosis with no effective treatment. The patient needs to understand this is a complication of the thermal capsulorrhaphy technique, which is why it was abandoned." "Management is symptomatic: activity modification to reduce symptoms, NSAIDs for pain and inflammation, possible intra-articular corticosteroid injections for symptom control." "If severe pain and functional limitation with significant arthritis, may require shoulder arthroplasty. However, outcomes of arthroplasty in young patients with chondrolysis are poor. This would be a salvage procedure only." "From a medicolegal perspective, this is complex. Thermal capsulorrhaphy was an accepted technique when it was being performed, but by 2010 it had been largely abandoned due to known complications. Timing of this patient's surgery would be relevant. The patient should be informed about the nature of the complication." **If No Chondrolysis - Isolated Recurrent Instability:** "If imaging shows no chondrolysis and the problem is isolated recurrent instability, this represents failure of the thermal capsulorrhaphy - an expected outcome given the known high failure rate." "Initial management would be conservative with structured rehabilitation trial. Rotator cuff and scapular strengthening following Burkhead-Rockwood protocol. Minimum 3-6 month trial before considering surgical intervention." **Surgical Management of Failed Thermal Capsulorrhaphy:** "If conservative management fails and patient has significant functional limitation, revision surgery would be considered. However, this is challenging:" "The previous thermal injury has created abnormal scar tissue with poor quality capsule. The normal anatomy is distorted. There may be areas of capsular necrosis or absence." "I would perform examination under anesthesia to quantify true structural laxity. If significant Grade 2-3 laxity confirmed, I would proceed with open inferior capsular shift rather than arthroscopic revision." "The open approach allows better assessment of capsular tissue quality, ability to work with scarred tissue, and more robust volume reduction. I would use T-capsulorrhaphy or lateral-based shift technique." "Intraoperative findings might include: thin, scarred capsule with areas of necrosis, poor tissue quality for suture holding, distorted anatomy from thermal injury." "I would be more aggressive with capsular shift while carefully monitoring ROM intraoperatively. May need to use heavier suture due to poor tissue quality. Rotator interval closure mandatory." "Postoperative protocol would be extended protection - 6-8 weeks immobilization given poor tissue quality and higher failure risk." **Patient Counseling:** "I would have a frank discussion with this patient about: The thermal capsulorrhaphy technique is now abandoned due to complications. His current symptoms represent either failure of the technique (expected) or development of chondrolysis (devastating)." "If revision surgery is needed, the success rate is lower than standard MDI revision (estimated 60-70%) due to poor capsular tissue quality from thermal injury. There is also ongoing risk of late chondrolysis development even years after thermal treatment." "Patient needs to understand this may be a chronic problem requiring long-term management and activity modification. Unrealistic to expect return to baseline shoulder function." **Examiner Follow-up: How would you approach discussing this with your colleague?** "This is a sensitive professional matter. I would approach the colleague privately and collegially. Would ask about the timing of when thermal capsulorrhaphy was performed - if this was in the late 1990s or early 2000s, it was an accepted technique at that time, though we now know it has poor outcomes." "Would discuss that thermal capsulorrhaphy is now completely abandoned and should not be performed. Would share the literature on failure rates and chondrolysis complications." "If the thermal capsulorrhaphy was performed recently (after 2010 when it was widely known to be ineffective and dangerous), this would be more concerning and might require discussion at a departmental level about practice patterns and patient safety." "From the patient's perspective, they deserve to know that this was a technique that has since been abandoned, which may explain their current symptoms. However, this should be communicated carefully and professionally." **Key Examination Points Demonstrated:** - Knowledge of thermal capsulorrhaphy history and abandonment - Understanding of chondrolysis complication - Systematic approach to assessing failed thermal treatment - Appropriate imaging workup - Realistic expectations for revision surgery - Professional approach to colleague discussion - Patient-centered communication about complications

KEY POINTS TO SCORE

Thermal capsulorrhaphy is ABANDONED due to failure and chondrolysis

Chondrolysis is devastating complication - no treatment

Recurrent instability expected with thermal technique (50-70% failure)

Professional approach to colleague discussion essential

COMMON TRAPS

✗Not recognizing thermal capsulorrhaphy as abandoned technique

✗Missing chondrolysis as cause of pain

✗Criticizing colleague inappropriately

LIKELY FOLLOW-UPS

"What is chondrolysis?"

"When was thermal capsulorrhaphy abandoned?"

"How would you approach discussing this with the colleague?"

MCQ Practice Points

High-Yield Multiple Choice Concepts

Diagnostic criteria for MDI:

Requires symptomatic instability in TWO or more directions (anterior, posterior, inferior)
Positive sulcus sign Grade II or III is pathognomonic
Atraumatic or minimal trauma history distinguishes from TUBS
Bilateral involvement in 50-80% of cases
Beighton score ≥4 indicates generalized hypermobility

AMBRII versus TUBS classification:

AMBRII: Atraumatic, Multidirectional, Bilateral, Rehabilitation, Inferior capsular shift, Interval closure
TUBS: Traumatic, Unidirectional, Bankart lesion, Surgery
Classic vignette: young female swimmer with bilateral shoulder looseness = AMBRII
Classic vignette: rugby player with anterior shoulder dislocation = TUBS

Exam Pearl

Q: How do you distinguish AMBRII from TUBS in an exam vignette?

A: AMBRII describes MDI pathway - Atraumatic and Multidirectional instability, often Bilateral, treat with Rehabilitation first, then Inferior capsular shift with rotator Interval closure if conservative fails. TUBS describes traumatic anterior instability - Traumatic onset, Unidirectional, Bankart lesion present, requires Surgery. Classic AMBRII vignette: young female swimmer with bilateral shoulder looseness. Classic TUBS vignette: rugby player with anterior dislocation.

Sulcus sign testing:

Pathognomonic examination finding for MDI
Grade I less than 1cm, Grade II 1-2cm, Grade III greater than 2cm
MUST test in neutral rotation AND external rotation
Persistent sulcus in external rotation indicates rotator interval incompetence
Always compare to contralateral shoulder

Stanmore Triangle Classification:

Type I: Traumatic, Structural (specific injury causing capsular damage)
Type II: Atraumatic, Structural (constitutional laxity, classic MDI)
Type III: Atraumatic, Non-Structural, Muscle Patterning (voluntary, psychological)
Type III should NOT undergo surgery - will fail
Identifying Stanmore type critical for treatment decisions

Exam Pearl

Q: What is the critical examination finding that distinguishes Stanmore Type III from Type I/II MDI?

A: Stanmore Type III patients demonstrate normal capsular laxity (Grade 0-1) on examination under anesthesia despite appearing lax when awake due to muscle patterning or voluntary control. This contrasts with Type I/II who have Grade 2-3 structural laxity under EUA. Surgery is contraindicated in Type III because there is no structural pathology to correct - always perform EUA before MDI surgery and abort if laxity is normal under anesthesia.

First-line treatment:

Rehabilitation is ALWAYS first-line for MDI (not surgery)
Burkhead-Rockwood protocol: 6-12 months structured physiotherapy
Success rate 80-90% with proper compliance
Four phases: rotator cuff strengthening, scapular stabilization, proprioception, sport-specific
Minimum 6 months trial required before declaring failure

Surgical indications:

Failed minimum 6 months structured rehabilitation
Documented compliance with therapy program
Persistent symptoms affecting function
Stanmore Type I or II (structural pathology)
Objective instability on examination (Grade 2-3 laxity)
Realistic expectations about outcomes

Surgical technique selection:

Open inferior capsular shift: gold standard, 85-90% success rate
Arthroscopic capsulorrhaphy: 70-85% success rate, less invasive
Thermal capsulorrhaphy: ABANDONED due to failure and chondrolysis
Rotator interval closure: required if sulcus positive in external rotation
T-capsulorrhaphy (Neer technique) is classic open approach

Exam Pearl

Q: Why is thermal capsulorrhaphy never the correct answer for MDI surgical treatment questions?

A: Thermal capsulorrhaphy was completely abandoned in the early 2000s due to unacceptably high failure rates (50-70%) and devastating complications including glenohumeral chondrolysis. Despite appearing in older literature, this technique should never be selected in modern exam questions. If it appears as an option, it is always wrong regardless of the clinical scenario presented.

Examination under anesthesia:

Performed before surgery to confirm structural laxity
Eliminates muscle guarding and voluntary control
Grade 0-1 laxity on EUA despite clinical symptoms = Stanmore Type III
If EUA normal laxity, abandon surgery (muscle patterning, not structural)
EUA guides surgical technique and extent of capsular shift

Complications:

Stiffness: most common (10-20%), prevent with ROM assessment intraoperatively
Recurrent instability: 10-25% depending on technique and patient factors
Axillary nerve injury: risk during inferior capsular work, stay above 6 o'clock
Chondrolysis: devastating complication of thermal capsulorrhaphy (now abandoned)
Subscapularis failure: after open technique, causes anterior instability

Postoperative rehabilitation:

6 weeks strict immobilization (longer than TUBS repair)
Passive ROM weeks 6-12, active ROM weeks 12-16
Strengthening not before 12 weeks
Return to sport minimum 6-9 months
Premature progression leads to capsular stretch and recurrence

Prognostic factors:

Beighton score ≥6 predicts higher failure rate
Bilateral involvement common but doesn't predict failure
Generalized connective tissue disorder (Ehlers-Danlos) poor prognosis
High-level overhead athletes have lower return to sport rate
Stanmore Type III should not undergo surgery

Common examination traps:

MDI does NOT require trauma history (atraumatic by definition)
Positive apprehension test suggests traumatic instability, NOT typical for MDI
Normal radiographs and MRI do not exclude MDI (clinical diagnosis)
Labral tears uncommon in pure MDI (attenuated labrum, not torn)
Thermal capsulorrhaphy is NEVER the answer (completely abandoned)

Exam Pearl

Q: What does a positive anterior apprehension test indicate in a patient with multidirectional laxity?

A: MDI patients typically have NEGATIVE apprehension test despite significant laxity because they lack the traumatic mechanism creating the fear response. A positive apprehension in a patient with multidirectional laxity suggests mixed pathology - traumatic anterior injury superimposed on underlying constitutional laxity - rather than pure MDI. This changes management as the Bankart lesion may need addressing along with capsular redundancy.

Evidence-based answers:

Burkhead-Rockwood study: 80% success with rehabilitation
Neer inferior capsular shift: 90% success rate, gold standard open technique
Gartsman study: arthroscopic 76% success versus open 89% success
Thermal capsulorrhaphy: abandoned due to 50-70% failure and chondrolysis risk
Stanmore classification: Type III surgery contraindicated

Exam Pearl

Q: What is the minimum duration of structured rehabilitation required before considering surgical treatment for MDI?

A: Six months is the minimum rehabilitation trial required before surgery is considered. The Burkhead-Rockwood protocol demonstrated 80% success rate with structured rehabilitation over 6-12 months. Patients who do not complete adequate physiotherapy should not be offered surgery, as premature surgical intervention has higher failure rates and patients miss the opportunity for successful conservative management.

Exam Pearl

Q: When should rotator interval closure be performed in addition to capsular shift for MDI?

A: Rotator interval closure should be added when the sulcus sign remains positive with the shoulder in external rotation. Normal anatomy closes the rotator interval when the arm is externally rotated, eliminating inferior translation. A persistent sulcus in external rotation indicates pathological rotator interval laxity that must be addressed surgically for successful outcome. Without interval closure in these patients, inferior instability will persist despite adequate capsular shift.

These high-yield points cover the most commonly tested MDI concepts in Orthopaedic examinations and should be memorized for rapid recall during MCQ sections.

Australian Context

MDI prevalence in Australia follows similar patterns to international data, with specific considerations for the Australian healthcare system and sporting culture.

Swimming is highly popular in Australia with high participation rates among adolescents and young adults, creating a higher proportion of MDI presentations related to overhead aquatic activities. Australian rules football and rugby participation, particularly the repetitive overhead marking and throwing actions, contributes to MDI development in predisposed individuals with underlying hypermobility. Surf lifesaving is uniquely Australian with overhead paddling and swimming creating specific MDI risk patterns.

Medicare provides coverage for specialist consultations and surgical procedures for arthroscopic capsulorrhaphy and open capsular shift. Public hospital treatment is available without out-of-pocket costs, though wait times can be significant. Private physiotherapy requires multiple sessions over 6-12 months for complete MDI rehabilitation, with Chronic Disease Management plans providing limited subsidized allied health sessions.

The Australian Orthopaedic Association recommends conservative management first-line for MDI, with a minimum 6-month rehabilitation trial before surgical consideration. Open inferior capsular shift is preferred over arthroscopic techniques for severe MDI. Sports Medicine Australia emphasizes early identification of at-risk athletes with hypermobility and preventive strengthening programs for overhead athletes.

Public hospital wait times for non-urgent shoulder instability range from 12-18 months for surgical consultation, with additional 6-12 months for surgery. Private practice offers faster access with specialist consultation within 2-8 weeks. Rural and remote patients face additional challenges with limited specialist access and increased travel costs, though telehealth options and the Patient Assisted Travel Scheme provide some support.

Major Australian research centers including the University of Melbourne, La Trobe University, and University of Sydney contribute to MDI literature with shoulder instability prevalence studies, surgical outcomes research, and sport-specific protocols for swimming and surf lifesaving.