import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **Location**: Courses 5-7cm distal to lateral acromion edge, wrapping posteriorly to anteriorly around surgical neck of humerus through quadrangular space **Protection**: Position lateral portal 2-3cm (not >5cm) below lateral acromion edge, use outside-in technique with spinal needle localization, avoid excessive distal instrumentation **Location**: Originates from anterior border and superior surface of acromion extending 2-3cm posteriorly, provides primary shoulder abduction power **Protection**: During acromioplasty, remain on inferior (undersurface) bone only, limit anterior resection to 5-7mm, burr should never extend beyond anterior acromion edge, preserve superior periosteum **Location**: Passes through suprascapular notch beneath superior transverse scapular ligament, innervates supraspinatus (50%) then curves around spinoglenoid notch to infraspinatus (50%) **Protection**: Avoid excessive medial dissection beyond scapular base, limit burr use near scapular spine medially, maintain visualization during medial acromioplasty **Location**: Supraspinatus lies directly beneath subacromial space inserting on superior facet greater tuberosity, infraspinatus posteriorly on middle facet, critical interval between them posteriorly **Protection**: During bursectomy use shaver with suction on oscillating mode (not aggressive), burr for acromioplasty should face superiorly (toward acromion) never inferiorly, probe cuff before and after to detect iatrogenic injury **Location**: Pierces coracobrachialis 5-8cm distal to coracoid tip (average 6cm), anterior portal placement risk if excessively medial or distal **Protection**: Anterior portal if needed should be lateral to coracoid tip, stay above subscapularis upper border, use outside-in with spinal needle localization, avoid blind trocar insertion ### Bigliani Acromion Morphology Classification Critical for surgical decision-making in subacromial impingement: **Type I - Flat (10%)** - Smooth flat undersurface - Minimal impingement risk - Often does NOT require acromioplasty - Consider other causes if symptomatic (internal impingement, cervical referred pain) **Type II - Curved (40%)** - Gentle curved undersurface - Moderate impingement risk - May benefit from conservative anteroinferior decompression - Assess for associated spur formation **Type III - Hooked (50%)** - Prominent anteroinferior hook - HIGHEST impingement risk - Clear mechanical block requiring acromioplasty - Primary indication for surgical decompression - Strong correlation with rotator cuff tears ### Neer Impingement Staging System Guides treatment selection and prognostication: **Stage I - Edema and Hemorrhage** - Age typically <25 years - Acute inflammation of bursa and cuff - Reversible pathology - Treatment: conservative (rest, NSAIDs, PT) - Surgery rarely indicated - Prognosis excellent with non-operative management **Stage II - Fibrosis and Tendinitis** - Age typically 25-40 years - Chronic bursal thickening - Rotator cuff fibrosis - Partial-thickness cuff tears may develop - Treatment: initial conservative 3-6 months, then consider surgery - PRIMARY surgical candidates for isolated SAD - Good surgical outcomes if mechanical impingement confirmed **Stage III - Bone Spurs and Tendon Rupture** - Age typically >40 years - Irreversible changes - Anteroinferior acromial osteophytes - Full-thickness rotator cuff tears common - AC joint arthritis often present - Treatment: surgery usually required (SAD + cuff repair + DCE) - Outcomes dependent on cuff tear size/reparability - Higher complexity procedures ### Coracoacromial Ligament Management Strategies **Traditional Approach - Complete Release** - Historical teaching: release CA ligament improves decompression - Technique: electrocautery detachment from anteroinferior acromion - Advantage: maximal subacromial space volume - Concern: loss of superior humeral restraint **Modern Approach - Preservation** - Current evidence-based trend: preserve CA ligament - Rationale: superior restraint especially with cuff deficiency - Technique: debride only thickened/calcified portions - Advantage: maintains superior stabilizer preventing escape - Critical with massive irreparable cuff tears **Middle Ground - Selective Debridement** - Remove only mechanically impinging portions - Preserve lateral CA ligament fibers - Balance decompression with stability - Individualize based on cuff status **Classification Impact on Management**: Bigliani Type I acromion with impingement symptoms should prompt search for alternative diagnoses (internal impingement, SLAP lesions, cervical pathology). Type III hooked acromion with positive impingement signs represents clear mechanical pathology amenable to surgical decompression. Recent evidence questions SAD benefit without structural acromion abnormality. ### Subacromial Space Anatomy **Boundaries** - Superior: Undersurface of acromion, AC joint, coracoacromial ligament - Inferior: Superior rotator cuff (supraspinatus primarily) - Anterior: Anterior acromion edge, CA ligament origin - Posterior: Posterior acromion - Medial: Base of acromion/scapular spine junction - Lateral: Greater tuberosity **Contents** - Subacromial-subdeltoid bursa (continuous structure) - Bursa normally thin, becomes hypertrophic in chronic impingement - Potential space becomes obliterated by bursal inflammation - Vascular supply: thoracoacromial, suprascapular, posterior circumflex ### Acromion Osseous Anatomy **Shape and Dimensions** - Anterior-posterior length: 4-5cm - Medial-lateral width: 2.5-3cm - Thickness: 7-10mm (limit resection to preserve strength) - Anteroinferior corner: PRIMARY impingement site - Unfused acromial apophysis (os acromiale): present 3-15%, predisposes to impingement **Deltoid Origin** - Originates anterior border and superior surface - Extends 2-3cm posteriorly along lateral acromion - Acromioplasty inferior surface only - preserve superior periosteum - Detachment causes abduction weakness ### Coracoacromial (CA) Arch **Anatomy** - CA ligament: triangular structure from lateral coracoid to anteroinferior acromion - Two bands: medial and lateral - Forms protective "roof" preventing superior humeral migration - Functionally part of "coracoacromial arch" constraining humeral head **Biomechanical Function** - Superior restraint against humeral head escape - Critical with rotator cuff deficiency (subscapularis, supraspinatus loss) - Anterosuperior escape pattern if CA ligament released with massive cuff tear ### Neurovascular Danger Zones **Axillary Nerve** - Origin: posterior cord (C5-C6) - Course: exits quadrangular space with posterior circumflex humeral artery - Position: 5-7cm distal to lateral acromion (range 4.5-8cm) - Wraps surgical neck humerus from posterior to anterior - Innervates: deltoid (entire muscle), teres minor, lateral shoulder skin - Injury presentation: deltoid paralysis, shoulder abduction weakness, lateral shoulder numbness **Suprascapular Nerve** - Origin: upper trunk (C5-C6) - Course: through suprascapular notch (beneath STSL), around spinoglenoid notch - Supraspinatus branch (50% fibers), infraspinatus branch (50% fibers) - At risk: excessive medial acromioplasty beyond scapular base - Injury presentation: supraspinatus/infraspinatus atrophy, external rotation weakness **Musculocutaneous Nerve** - Origin: lateral cord (C5-C7) - Pierces coracobrachialis 5-8cm distal to coracoid (mean 6cm, range 3-9cm) - At risk: anterior portal if excessively medial/distal to coracoid - Injury presentation: biceps weakness (flexion, supination), lateral forearm numbness ### Rotator Cuff Bursal Surface Anatomy **Supraspinatus** - Most anterior-superior, primary structure in subacromial space - Insertion: superior facet greater tuberosity (1.5cm × 1.5cm footprint) - Most vulnerable to impingement and iatrogenic shaver injury **Infraspinatus** - Posterior to supraspinatus - Insertion: middle facet greater tuberosity - Critical interval between supraspinatus and infraspinatus posteriorly **Functional CA Arch**: The coracoacromial ligament is NOT simply an impinging structure - it serves critical biomechanical function as superior restraint. This is why modern practice trends toward preservation. If massive irreparable cuff tear exists, CA ligament release can precipitate anterosuperior escape. Always assess cuff integrity before deciding CA ligament management. ### Patient Positioning Options **Beach Chair Position (Most Common)** - Advantages: - Anatomic orientation familiar - Easy conversion to open if needed - Better access to anterior/superior shoulder - Lower fluid extravasation risk - No traction-related nerve complications - Disadvantages: - Hypotension risk with upright positioning - Requires cerebral perfusion monitoring consideration - More difficult posterior access - Setup: 60-70° upright, head in gel holder, pneumatic arm positioner **Lateral Decubitus Position** - Advantages: - Excellent posterior portal access - Arm traction improves joint distraction - Better glenohumeral joint visualization - Stable blood pressure - Disadvantages: - Disorienting anatomy initially - Traction-related neuropraxia risk (limit 10-12 lbs) - Difficult conversion to open - Increased fluid extravasation into soft tissues - Setup: beanbag positioning, 10-12 lbs arm traction, 20-30° forward flexion ### Portal Placement Variations **Standard Three-Portal Technique** - Posterior viewing portal (soft spot) - Lateral working portal (primary subacromial work) - Anterior portal (optional, for visualization or anterior work) **Modified Neviaser Portal (Superolateral)** - Position: 2cm posterior, 2cm medial to anterolateral acromion corner - Advantage: excellent visualization of anteroinferior acromion - Disadvantage: risk of superior labrum injury, supraspinatus injury **Portal of Wilmington (Posterolateral)** - Position: posterolateral corner acromion, between standard posterior and lateral - Advantage: improved lateral acromioplasty access - Used for primary working portal in some techniques ### Acromioplasty Technique Variations **Anteroinferior Spur Removal Only** - Conservative approach: remove only obvious spur - Preserve acromion morphology otherwise - Advantage: minimal bone removal, preserve deltoid - Best for: focal spur with otherwise Type I/II acromion **Complete Flat Undersurface Reshaping** - Aggressive approach: convert any morphology to Type I flat - Systematic anterior to posterior, lateral to medial - Advantage: comprehensive decompression - Risk: over-resection, deltoid dysfunction - Best for: Type III hooked acromion with extensive pathology **Image-Guided Acromioplasty** - Use of intraoperative fluoroscopy - Ensure adequate anterior and lateral decompression - Prevents over-resection - Useful for revision cases ### Burr Selection and Technique **5.0-5.5mm Oval Burr** - Most common choice - Smooth contouring ability - Efficient bone removal **4.0mm Round Burr** - More conservative - Better control in tight spaces - Longer operative time **Burr Orientation** - Cutting surface TOWARD acromion (superior) - Never direct inferiorly toward cuff - Systematic overlapping passes - Frequent withdrawal to assess progress ### Distal Clavicle Excision Integration **Indications for Combined SAD + DCE** - AC joint arthritis confirmed (imaging, examination) - Positive cross-body adduction test - Failed AC joint injections - Age >50 with AC osteophytes **DCE Technique During SAD** - Identify AC joint after bursectomy - Burr resection 5-7mm distal clavicle - Preserve superior and posterior capsule (stability) - Remove anterior-inferior bone only - Create 5-7mm gap visible on fluoroscopy **Beach Chair vs Lateral Position**: In examinations, demonstrate knowledge of both. State your preference (usually beach chair) but acknowledge advantages of each. Key point: "I prefer beach chair for anatomic orientation and ability to convert to open if unexpected cuff tear found requiring complex repair, but lateral decubitus provides excellent distraction for glenohumeral pathology assessment." ### Landmark Clinical Trials **CSAW Trial (2018) - UK Multicenter RCT** - Design: 313 patients, arthroscopic SAD vs active monitoring vs placebo (sham surgery) - Results: NO significant difference in outcomes at 6 months or 1 year - Conclusion: Arthroscopic SAD no better than sham surgery for subacromial pain - Impact: Major paradigm shift questioning SAD efficacy - Limitation: Excluded patients with full-thickness cuff tears, included all acromion types - Clinical interpretation: Patient selection critical - benefit likely limited to TRUE mechanical impingement (Type III acromion with spur) **FIMPACT Trial (2019) - Finnish Multicenter RCT** - Design: 210 patients, SAD vs diagnostic arthroscopy vs PT alone - Results: Small benefit SAD over PT at 2 years, not clinically significant - Conclusion: Exercise therapy as effective as surgery - Quality of life improvements similar all groups **Cochrane Review (2019) - Systematic Review** - Pooled data: moderate-quality evidence of no benefit SAD over placebo - Small benefit over PT not clinically meaningful - Recommendation: Consider conservative management first-line ### Success Rates and Predictive Factors **Overall Success Rates** - Good-excellent results: 65-90% (highly variable by patient selection) - Complete pain relief: 50-60% - Return to previous activity level: 70-80% **Positive Predictive Factors** - True mechanical impingement (Type III acromion, visible spur) - Shorter symptom duration (<1 year better than >2 years) - Positive response to subacromial injection (>50% temporary relief) - Younger age (<60 years) - Workers compensation NOT involved - No associated psychiatric comorbidity **Negative Predictive Factors** - Normal Type I acromion morphology (wrong diagnosis) - Long symptom duration (>2 years) - Workers compensation claim - Multifactorial pain (cervical referred pain, fibromyalgia) - Secondary gain issues - Previous failed surgery ### Complication Rates from Literature **Common Complications** - Persistent pain: 10-20% (often indicates incorrect diagnosis) - Stiffness: 5-10% (usually from over-protection post-operatively) - Deltoid dysfunction: 1-3% (from over-aggressive acromioplasty) **Rare Complications** - Acromion fracture: <1% (from >10mm resection) - Nerve injury: <1% (axillary from low portal, suprascapular from medial work) - Infection: 0.5-1% (lower than open surgery) ### Revision Surgery Outcomes **Indications for Revision SAD** - Inadequate initial decompression (residual spur, incomplete acromioplasty) - Recurrent spur formation - Missed AC joint pathology - Os acromiale instability **Revision Success Rates** - Lower than primary: 60-70% good-excellent results - Critical: ensure correct diagnosis before revision - Rule out alternative pain generators (cervical, referred, chronic pain syndrome) ### Cost-Effectiveness Analysis **Conservative Management** - Lower initial cost - May require prolonged PT (3-6 months) - Multiple physician visits, injections **Surgical Management** - Higher initial cost - Faster return to work (potentially) - Risk of complications, revision **Current Recommendations** - Minimum 3-6 months conservative treatment before surgery - Reserve surgery for mechanical impingement with structural acromion abnormality - Shared decision-making discussing evidence limitations **Addressing CSAW in Exams**: Examiners WILL ask about recent negative evidence. Proper response: "The CSAW trial showed no benefit of SAD over placebo, which has changed practice. I now reserve SAD for patients with TRUE mechanical impingement - specifically Bigliani Type III hooked acromion with visible anteroinferior spur and positive impingement signs. The trial included all acromion types, many likely without mechanical pathology. Patient selection is critical." ### Pathophysiology of Subacromial Impingement **Extrinsic Compression (Primary Mechanism)** - Mechanical compression rotator cuff between humeral head and coracoacromial arch - Occurs in forward flexion 60-120° (impingement zone) - Contributing factors: - Acromial morphology (Type III hooked) - Anteroinferior acromial spurs - AC joint osteophytes - CA ligament ossification/thickening - Os acromiale instability - Subacromial bursal hypertrophy **Intrinsic Cuff Degeneration (Secondary Factor)** - Age-related tendon degeneration - Hypovascularity in supraspinatus "critical zone" (1cm proximal to insertion) - Repetitive microtrauma - May occur WITHOUT impingement (primary cuff pathology) - Explains why some patients fail SAD (intrinsic not extrinsic problem) **Combined Model (Most Common)** - Extrinsic compression on degenerating tendon - Bursal inflammation from chronic impingement - Pain from bursitis AND partial cuff injury - Cycle of inflammation and mechanical compression ### Differential Diagnosis of Subacromial Pain Critical to exclude before considering SAD: **Internal Impingement** - Posterior rotator cuff impingement against posterosuperior glenoid rim - Occurs in abduction-external rotation (throwing position) - SLAP lesions, posterior labral tears - Partial articular-sided cuff tears (PASTA lesions) - Treatment: rehabilitation, posterior labral repair, NOT SAD **Cervical Radiculopathy (C5-C6)** - Referred shoulder pain - May mimic impingement - Neck pain, radicular symptoms - Positive Spurling test - MRI cervical spine if suspected **Adhesive Capsulitis** - Global ROM restriction (passive and active) - Different treatment (manipulation, capsular release) - Can coexist with impingement **Calcific Tendinitis** - Acute severe pain - Calcium deposit visible on X-ray - May respond to lavage/excision - Often spontaneously resolves **Rotator Cuff Tear** - Weakness, positive lag signs - MRI confirmation - Treatment: repair, not isolated SAD ### Os Acromiale Management **Prevalence**: 3-15% population, bilateral 60% **Pathophysiology** - Unfused acromial apophysis (typically meso-acromion) - Mobile os fragment causes impingement - Unstable with deltoid contraction **Diagnosis** - Axillary lateral X-ray shows unfused fragment - CT scan confirms location and size - MRI shows associated cuff pathology **Treatment Options** - Small stable os: acromioplasty alone - Large unstable os: ORIF with screws/plate - Highly unstable, cuff tear: excision (if <2/3 acromion) ### Biologic Augmentation Strategies **Platelet-Rich Plasma (PRP)** - Controversial benefit - May reduce post-operative inflammation - Limited evidence in SAD specifically - More data in rotator cuff repair **Growth Factors** - Experimental - No proven benefit in SAD **Hyaluronic Acid** - Possible role in bursal inflammation - Insufficient evidence ### Revision SAD - Technical Considerations **Pre-operative Assessment** - Review operative reports: what was done initially? - Advanced imaging: CT for bone (acromion shape), MRI for cuff - Diagnostic subacromial injection: if good temporary relief, mechanical component exists **Intra-operative Findings** - Inadequate anterior decompression most common - Retained anteroinferior spur - Incomplete bursectomy from first surgery - Missed AC joint pathology - Os acromiale instability **Technical Execution** - More difficult visualization (scarring) - Complete scar bursectomy mandatory - Assess previous acromioplasty adequacy - Address AC joint if not done - Consider open approach if arthroscopic difficult **Outcomes** - Lower success than primary (60-70% vs 75-85%) - Realistic patient expectations critical - Rule out non-mechanical pain sources **Os Acromiale Recognition**: In examination scenarios describing failed SAD with persistent pain, consider os acromiale. State: "I would review pre-operative imaging specifically looking for os acromiale on axillary lateral X-ray - this is an unfused acromial apophysis causing mobile fragment impingement. If present and unstable, requires ORIF or excision, not simple acromioplasty." **Patient Position**: Beach chair position at 60-70° upright OR lateral decubitus with arm traction (10-12lbs). Beach chair preferred for conversion to open if needed, easier anatomic orientation. Arm in pneumatic holder allowing free movement. **Surgical Approach**: Arthroscopic via standard portals: posterior viewing portal, lateral working portal, anterior portal as needed. Focus on subacromial space for decompression. **Incision**: Multiple small arthroscopic portals (5-8mm): posterior viewing portal (soft spot), lateral working portal (2-3cm below lateral acromion), +/- anterior portal if needed for visualization or instrumentation. ### Step 1: Patient Positioning and Surface Marking Patient Positioning and Surface Marking: Position in beach chair at 60-70° upright (preferred) or lateral decubitus with arm traction. Beach chair: head in gel donut/holder, arm in pneumatic arm holder allowing abduction/rotation. Mark ALL bony landmarks: anterior acromion edge, lateral acromion edge, posterior acromion edge, clavicle, AC joint, coracoid process, scapular spine. Mark planned portals: posterior (soft spot), lateral, anterior if needed. **Technical Tip**: EXAM KEY: 'I use beach chair positioning which allows easy conversion to open if needed and provides anatomic orientation. I mark the acromion extensively - ANTERIOR edge (deltoid origin at risk), LATERAL edge (portal reference), POSTERIOR edge (portal site), and AC joint (medial limit). The soft spot is 2cm inferior and 1cm medial to posterolateral acromion corner for posterior portal.' - Hypotensive event with beach chair positioning (cerebral hypoperfusion) - ensure adequate blood pressure monitoring, consider vasopressors - Inadequate landmark identification leading to malpositioned portals and neurovascular injury - Patient positioning instability during procedure causing movement and visualization difficulty ### Step 2: Establish Posterior Portal and Diagnostic Glenohumeral Arthroscopy Establish Posterior Portal and Diagnostic Glenohumeral Arthroscopy: Create posterior portal at soft spot (2cm inferior, 1cm medial to posterolateral acromion corner). Enter glenohumeral joint directed toward coracoid. Perform systematic glenohumeral examination: biceps tendon, superior labrum, anterior labrum/capsule, subscapularis (look for partial tears), inferior pouch, posterior structures, rotator cuff articular surface (assess for partial-thickness tears >50% = repair), humeral head and glenoid cartilage. **Technical Tip**: EXAM KEY: 'I start with diagnostic glenohumeral arthroscopy even though this is primarily a subacromial procedure. This identifies: (1) articular-sided cuff tears >50% thickness requiring repair, (2) biceps pathology requiring tenotomy/tenodesis, (3) labral tears, (4) arthritis. These findings may change surgical plan. I document all pathology systematically.' - Missed intra-articular pathology requiring treatment (partial articular-sided cuff tears, SLAP lesions, biceps pathology) - Cartilage damage from instruments during diagnostic arthroscopy - Inadequate assessment leading to wrong diagnosis or incomplete treatment ### Step 3: Establish Lateral Portal Establish Lateral Portal: Create lateral portal under direct arthroscopic visualization OR using anatomic landmarks. Position: 2-3cm distal to lateral acromion edge, in line with posterior border of clavicle. Use outside-in technique with spinal needle for localization, or establish from inside-out after entering subacromial space. This is primary WORKING portal for bursectomy and acromioplasty. Critical: stay >5cm from lateral acromion edge (axillary nerve). **Technical Tip**: EXAM KEY: 'The lateral portal is my primary working portal for subacromial work. I position it 2-3cm below the lateral acromion edge, in line with the posterior clavicle. This gives optimal angle for acromioplasty. AXILLARY NERVE is 5-7cm below acromion - I ensure portal stays above this safety zone. I can localize with spinal needle under visualization after entering subacromial space.' - Axillary nerve injury from portal placed too distal (>5cm from acromion) - causes deltoid paralysis and shoulder abduction weakness - Poor working angle from portal too proximal or posterior making acromioplasty technically difficult - Deltoid injury from portal creation especially if multiple attempts ### Step 4: Enter Subacromial Space Enter Subacromial Space: Transition scope from glenohumeral joint to subacromial space. Technique: redirect scope posteriorly and superiorly from posterior portal, feel 'pop' as enter subacromial space. Alternatively, create new lateral or posterolateral portal directly into subacromial space. Subacromial space is potential space between acromion above and rotator cuff below, filled with bursa. **Technical Tip**: EXAM KEY: 'I transition to the subacromial space from the posterior portal. As I redirect the scope superiorly and posteriorly, I feel a POP as I enter the space between the acromion and cuff. This is a potential space filled with inflamed bursa in impingement. I can also enter via lateral portal if established.' - Difficulty entering space from adhesions and severe inflammation requiring gentle blunt dissection - Cuff injury during entry particularly with forceful scope advancement - Wrong space identification (intra-deltoid plane) from incorrect trajectory ### Step 5: Subacromial Bursectomy Subacromial Bursectomy: Perform COMPLETE bursectomy using shaver and/or radiofrequency device to visualize anatomy. Remove all inflamed, hypertrophic bursal tissue. Start laterally, work medially to AC joint and anteriorly to CA ligament. Bursectomy is essential for visualization. Once bursa removed, can clearly see: acromion undersurface, CA ligament, cuff (bursal surface), greater tuberosity, AC joint. Maintain hemostasis. **Technical Tip**: EXAM KEY: 'COMPLETE bursectomy is the MOST IMPORTANT step - without it, cannot see anatomy for safe acromioplasty. I use shaver and radiofrequency to remove all bursal tissue. In chronic impingement, bursa is massively hypertrophic. Once cleared, I can see the undersurface of the acromion, identify the CA ligament anteriorly, and assess the cuff. The bursa itself is often the pain generator.' - Incomplete bursectomy causing poor visualization and unsafe acromioplasty with risk of cuff injury - Cuff injury with aggressive shaver use - use oscillating mode with suction portal oriented away from cuff - Bleeding obscuring view requiring meticulous hemostasis with radiofrequency or epinephrine irrigation - Excessive fluid extravasation into soft tissues from prolonged high pump pressure ### Step 6: Identify Acromial Anatomy and Assess Impingement Identify Acromial Anatomy and Assess Impingement: After bursectomy, systematically identify: (1) Acromion undersurface - flat, curved, or hooked (Bigliani Type I, II, III), (2) Anteroinferior acromial spur (if present), (3) CA ligament insertion on anterior acromion, (4) AC joint medially, (5) Rotator cuff condition (intact, partial tear, full tear). Assess impingement: spur present, Type II/III acromion creating mechanical block, CA ligament thickened/calcified. **Technical Tip**: EXAM KEY: 'I assess the acromion morphology: Type I FLAT (no impingement), Type II CURVED (mild), Type III HOOKED (significant mechanical impingement). I look for anteroinferior SPUR which is often the main impinging structure. The CA ligament may be thickened or calcified. I assess cuff from bursal side for partial or full-thickness tears. This assessment determines extent of decompression needed.' - Failure to identify true pathology leading to inappropriate or inadequate decompression - Unnecessary decompression in Type I acromion where impingement is not mechanical cause - Missing full-thickness cuff tear requiring repair not just decompression ### Step 7: Coracoacromial Ligament Management Coracoacromial Ligament Management: CA ligament management is CONTROVERSIAL. Options: (1) PRESERVE ligament (newer trend) - it provides superior restraint especially if cuff deficient, (2) RELEASE ligament (traditional) - improves decompression, or (3) DEBRIDE thickened portion only. If releasing: use electrocautery or radiofrequency to detach CA ligament from anteroinferior acromion. Release from lateral to medial. Preserve deltoid attachment above. **Technical Tip**: EXAM KEY: 'CA ligament management is debated. TRADITIONAL teaching: release CA ligament for decompression. CURRENT trend: PRESERVE CA ligament as it acts as superior humeral head restraint, especially important with rotator cuff deficiency. I generally preserve or debride only thickened portion. If massive cuff tear present, I definitely preserve CA ligament as superior stabilizer.' - Deltoid detachment from aggressive anterior dissection extending beyond anteroinferior acromion edge - Loss of superior restraint if CA ligament released with massive cuff tear causing anterosuperior escape - Bleeding from CA ligament release requiring careful hemostasis ### Step 8: Anteroinferior Acromioplasty - Initial Shaping Anteroinferior Acromioplasty - Initial Shaping: Use motorized burr (typically 5.0-5.5mm round or oval burr) to perform acromioplasty. Start at ANTEROINFERIOR corner - this is primary impingement site. Goal: create FLAT Type I acromion undersurface. Remove anteroinferior spur and any hooked portion. Work from lateral to medial. Stay on BONE (protecting deltoid above). Limit resection to 5-7mm maximum thickness to preserve bone stock and deltoid origin. **Technical Tip**: EXAM KEY: 'I use a burr to reshape the anteroinferior acromion. The goal is Type I FLAT undersurface. I start anterolaterally where impingement is worst and work medially. I stay directly ON BONE to protect deltoid origin which is on the superior surface. I limit resection to 5-7mm - over-resection causes deltoid dysfunction and acromion fracture. I create smooth contour, no sharp edges.' - Over-resection exceeding 7mm thickness causing deltoid dysfunction and acromion fracture risk - Deltoid detachment from burr extending off anterior edge onto superior surface - Inadequate decompression from too conservative resection leaving residual impingement - Acromial fracture during surgery or post-operatively from excessive bone removal - Burr injury to cuff below from improper burr orientation - always face cutting surface superiorly ### Step 9: Complete Acromioplasty - Smooth Contouring Complete Acromioplasty - Smooth Contouring: Continue acromioplasty working systematically from anterior to posterior, lateral to medial. Create smooth continuous flat undersurface. Remove all osteophytes. Test with probe - should have smooth gliding surface without catching. Common areas: anteroinferior corner (primary), lateral edge, anterior transition to CA ligament attachment. Stop medially at AC joint - do not enter joint unless diseased. **Technical Tip**: EXAM KEY: 'I complete the acromioplasty by creating a smooth continuous flat surface. I test with probe - should glide smoothly without any catching or rough areas. The anteroinferior region is most critical but I ensure entire undersurface is flat. I stop at the AC JOINT medially - no reason to enter unless there is AC joint pathology.' - Irregular surface with rough areas causing recurrent symptoms and persistent impingement - AC joint violation when unnecessary causing post-operative AC joint pain - Excessive bleeding from bone requiring bone wax or epinephrine irrigation - Asymmetric resection creating unbalanced mechanics ### Step 10: Assess Rotator Cuff from Bursal Surface Assess Rotator Cuff from Bursal Surface: With clear visualization after bursectomy and acromioplasty, assess cuff thoroughly from bursal surface. Look for: full-thickness tears (already assessed from articular side), bursal-sided partial tears, cuff thinning, degenerative changes. Probe cuff to assess integrity. If full-thickness tear found: document size, consider repair. If partial bursal-sided tear <50%: debride only. If >50%: consider completion and repair. **Technical Tip**: EXAM KEY: 'With excellent visualization, I thoroughly assess the cuff from the bursal surface. I probe the cuff to identify: full-thickness tears (felt tear extending through), bursal-sided partial tears (visible fraying), thinning. Combined with articular-side assessment, I determine if repair needed. PARTIAL tear <50% thickness from one side: DEBRIDEMENT only. Partial >50% or combined articular + bursal >50% total: consider REPAIR.' - Missing full-thickness tear requiring repair leading to poor outcomes - Underestimating partial tear depth causing inadequate treatment - Unnecessary completion of partial tear when debridement sufficient - Iatrogenic cuff injury from probing or instrumentation ### Step 11: Distal Clavicle Excision (if indicated) Distal Clavicle Excision (if indicated): If AC joint arthritis present (osteophytes, pain with cross-body test), perform distal clavicle excision. Identify AC joint capsule medially on acromion. Use burr to resect distal 5-7mm of clavicle. Resection creates 5-7mm gap. Preserve SUPERIOR and POSTERIOR capsule for stability. Remove anterior-inferior bone. Test stability - should have <5mm translation. If unstable, consider CA ligament preservation/reconstruction. **Technical Tip**: EXAM KEY: 'I perform DCE if AC joint arthritis present - identified by osteophytes, joint space narrowing, positive cross-body test. I resect 5-7mm of distal clavicle using burr. CRITICAL: preserve SUPERIOR and POSTERIOR capsule to prevent AC joint instability. I remove anterior and inferior bone only. Post-op gap is 5-7mm. Inadequate resection (<5mm) causes persistent pain; excessive (>10mm) causes instability.' - AC joint instability from excessive resection or superior/posterior capsule violation causing cosmetic deformity and pain - Inadequate resection less than 5mm causing persistent AC joint pain - Superior capsule violation causing vertical instability - Excessive bleeding from clavicle bone requiring careful hemostasis ### Step 12: Hemostasis and Final Assessment Hemostasis and Final Assessment: Achieve hemostasis using radiofrequency, electrocautery, or epinephrine irrigation. Reduce arthroscopic pump pressure to identify bleeding. Remove any loose bone fragments or debris. Final assessment: smooth acromion undersurface, no residual spur or osteophytes, intact rotator cuff (or repaired if torn), adequate subacromial space created, AC joint resected if needed. Test impingement signs: abduction and rotation should not cause mechanical block. **Technical Tip**: EXAM KEY: 'I achieve meticulous hemostasis - post-op hematoma causes pain and stiffness. I reduce pump pressure to unmask bleeding sources. I remove all debris and loose fragments. Final check: smooth acromion, no mechanical block with motion, cuff intact. I test impingement - with decompression, cuff should glide freely under acromion through full ROM.' - Persistent bleeding causing post-operative hematoma, pain and stiffness - Retained loose bodies causing mechanical symptoms and chondral damage - Incomplete decompression from inadequate assessment - Missed pathology not addressed during surgery ### Step 13: Assess Range of Motion Assess Range of Motion: Test passive ROM: forward flexion, abduction, internal and external rotation. Should achieve full or near-full ROM smoothly without mechanical impingement. No catching or grinding. If limited ROM, assess for: inadequate decompression, adhesive capsulitis requiring manipulation, cuff pathology. Document ROM. Gentle manipulation can be performed under anesthesia if frozen shoulder component identified. **Technical Tip**: EXAM KEY: 'I test passive ROM with decompression complete. Should achieve smooth full motion without catching. If ROM limited: assess reason - inadequate decompression (revise), adhesive capsulitis (gentle manipulation), or cuff tear (repair). I document final ROM. Gentle manipulation under anesthesia is safe and effective for concomitant stiffness.' - Forceful manipulation causing iatrogenic fracture (proximal humerus, acromion) or cuff tear - Unrecognized inadequate decompression causing persistent symptoms - Brachial plexus injury from aggressive manipulation especially in stiff shoulders ### Step 14: Closure and Injection Closure and Injection: Irrigate subacromial space thoroughly to remove debris. Inject long-acting local anesthetic with epinephrine into subacromial space for post-operative pain control (e.g., 20mL 0.25% Marcaine with 1:200,000 epinephrine). Consider corticosteroid injection (controversial - may impair healing). Remove instruments under direct visualization. Remove cannulas. Close portals with nylon or absorbable suture. Apply sterile dressings. **Technical Tip**: EXAM KEY: 'I irrigate thoroughly and inject long-acting local anesthetic into the subacromial space - this provides excellent post-operative pain control for 12-18 hours. I typically inject 20mL of 0.25% Marcaine with epinephrine. Corticosteroid injection is CONTROVERSIAL - may improve pain but concerns about healing impairment especially if cuff repair performed. I close portals with simple sutures.' - Inadequate irrigation leaving debris causing inflammation - Local anesthetic toxicity from excessive dose (rare but serious - cardiac toxicity) - Skin bridge necrosis if portals placed too close together - Infection risk from inadequate sterile technique ### Step 15: Post-operative Protocol and Patient Education Post-operative Protocol and Patient Education: Apply sling for COMFORT only (not mandatory). Initiate early mobilization protocol: IMMEDIATE active and passive ROM exercises (no restriction for isolated SAD). PT starting day 1-2. Strengthening at 2-4 weeks. Return to activity 4-8 weeks. Emphasize: this is low restriction surgery if isolated decompression. Educate on wound care, pain management, therapy compliance. Different protocol if concurrent cuff repair. **Technical Tip**: EXAM KEY: 'Post-operative protocol for isolated SAD is MINIMAL restriction. Sling for comfort only 1-3 days. I encourage IMMEDIATE ROM - both active and passive. This is fundamentally different from cuff repair which requires protection. Early motion prevents stiffness. PT focuses on ROM first, then rotator cuff and scapular strengthening. Most patients return to full activity 6-12 weeks. Success depends on appropriate patient selection and addressing true mechanical impingement.' - Over-protection causing iatrogenic stiffness and frozen shoulder - Inadequate therapy compliance leading to poor outcomes - Wrong patient expectations regarding pain resolution timeline (gradual over 3-6 months, not immediate) - Recurrence if underlying biomechanics (scapular dyskinesis, poor posture) not addressed with therapy **Additional Complications:** - Recurrent impingement from inadequate decompression (incomplete spur removal, insufficient acromioplasty) - Suprascapular nerve injury from excessive medial dissection (rare <0.5%) - Infection deep or superficial (0.5-1% - lower than open surgery) - AC joint instability if DCE performed with excessive resection >10mm or capsule violation - Bleeding/hematoma requiring drainage if massive - Instrument breakage with retained fragment - Fluid extravasation into soft tissues (extensive subcutaneous emphysema, pneumothorax rare) **ISOLATED SUBACROMIAL DECOMPRESSION (No Cuff Repair):** - Sling for comfort only: 1-3 days (remove when comfortable) - ROM: IMMEDIATE active and passive exercises - NO restrictions - Physical therapy: Start day 1-2, focus on ROM restoration - Strengthening: Begin 2-4 weeks with rotator cuff and scapular stabilizers - Return to work: Sedentary 1-2 weeks, manual labor 6-8 weeks - Return to sport: Non-contact 6-8 weeks, contact 10-12 weeks - Key message: Early motion prevents stiffness, this is NOT a protected procedure **WITH CONCURRENT ROTATOR CUFF REPAIR:** - Sling immobilization: 4-6 weeks continuous - ROM: Passive only 0-6 weeks, active-assisted 6-12 weeks, active after 12 weeks - Physical therapy: Controlled passive ROM only, protect repair - Strengthening: Delayed until 12+ weeks - Return to activity: Prolonged 4-6 months - Different protocol - repair protection takes precedence **Pain Management:** - Multimodal analgesia: acetaminophen, NSAIDs (if no contraindication) - Opioids: minimal use, 3-5 days maximum - Subacromial local anesthetic injection provides 12-18 hours excellent pain control - Ice therapy first 48-72 hours - Expect gradual pain improvement over 3-6 months (not immediate resolution) **Wound Care:** - Waterproof dressings 48 hours - Shower after 48 hours, no submersion 2 weeks - Suture removal 10-14 days if non-absorbable - Monitor for infection signs (increasing pain, erythema, drainage, fever) **Follow-up Schedule:** - 2 weeks: wound check, suture removal, ROM assessment - 6 weeks: pain and function assessment, advance strengthening - 3 months: outcome evaluation, return to activity clearance - 6-12 months: final outcome assessment ## References 1. Beard DJ, Rees JL, Cook JA, et al. Arthroscopic subacromial decompression for subacromial shoulder pain (CSAW): a multicentre, pragmatic, parallel group, placebo-controlled, three-group, randomised surgical trial. Lancet. 2018;391(10118):329-338. doi:10.1016/S0140-6736(17)32457-1 2. Paavola M, Malmivaara A, Taimela S, et al. Subacromial decompression versus diagnostic arthroscopy for shoulder impingement: randomised, placebo surgery controlled clinical trial. BMJ. 2018;362:k2860. doi:10.1136/bmj.k2860 3. Hao Q, Devji T, Zeraatkar D, et al. Minimal important differences for improvement in shoulder condition patient-reported outcomes: a systematic review to inform a BMJ Rapid Recommendation. BMJ Open. 2019;9(2):e028777. doi:10.1136/bmjopen-2018-028777 4. Bigliani LU, Morrison DS, April EW. The morphology of the acromion and its relationship to rotator cuff tears. Orthop Trans. 1986;10:228. 5. Neer CS 2nd. Anterior acromioplasty for the chronic impingement syndrome in the shoulder: a preliminary report. J Bone Joint Surg Am. 1972;54(1):41-50. 6. Chahal J, Mall N, MacDonald PB, et al. The role of subacromial decompression in patients undergoing arthroscopic repair of full-thickness tears of the rotator cuff: a systematic review and meta-analysis. Arthroscopy. 2012;28(5):720-727. doi:10.1016/j.arthro.2011.11.022 7. Ketola S, Lehtinen J, Rousi T, et al. No evidence of long-term benefits of arthroscopic acromioplasty in the treatment of shoulder impingement syndrome: Five-year results of a randomised controlled trial. Bone Joint Res. 2013;2(7):132-139. doi:10.1302/2046-3758.27.2000163 8. Sambandam SN, Khanna V, Gul A, Mounasamy V. Rotator cuff tears: An evidence based approach. World J Orthop. 2015;6(11):902-918. doi:10.5312/wjo.v6.i11.902 9. Karnes JM, Harrier CD, Bernas GA, Weiss AP, Akelman E. Anterior portal anatomy for shoulder arthroscopy: defining a safety zone. Arthroscopy. 2014;30(12):1521-1525. doi:10.1016/j.arthro.2014.07.011 10. Ponce BA, Kundukulam JA, Pflugner R, Abrams RA, Vrahas MS. Shoulder arthroscopy in the beach chair position: risk of arterial air embolism. Arthroscopy. 2009;25(4):481-482. doi:10.1016/j.arthro.2009.01.006

Arthroscopic Subacromial Decompression (Acromioplasty) for Impingement Syndrome

Arthroscopic Subacromial Decompression (Acromioplasty) for Impingement Syndrome