High Yield Overview

SHOULDER ARTHROPLASTY REVISION

Extended deltopectoral approach, component extraction, bone deficiency management, soft tissue reconstruction | advanced-expert

Critical Danger Structures

Axillary Nerve

Location: Exits quadrilateral space posteriorly, crosses inferior glenohumeral joint capsule at 6 o'clock position, runs on deep surface of deltoid 5-7cm below acromion. Protection: Identify early during inferior capsular release, use nerve stimulator in scarred tissue, limit inferior retraction force and duration, protect during glenoid exposure

Musculocutaneous Nerve

Location: Enters conjoint tendon 3-8cm distal to coracoid tip (mean 5-6cm). Location distorted by scarring from previous deltopectoral approach. Protection: Identify conjoint tendon early, limit medial retraction on conjoint, avoid dissection >8cm distal to coracoid, use nerve stimulator if anatomy unclear

Radial Nerve

Location: Spirals around posterior humeral shaft in spiral groove, 10-14cm proximal to lateral epicondyle, 15-18cm distal to humeral head. At risk with extended approach or long stem revision. Protection: Limit distal humeral dissection, stay anterior when extending exposure, identify nerve before humeral window osteotomy if extended approach, use image intensification to confirm stem length

Brachial Plexus & Axillary Vessels

Location: Anterior and medial to surgical field, protected by pectoralis minor and conjoint tendon. Risk increased in revision due to scarring and distorted anatomy. Protection: Stay lateral to conjoint tendon, avoid aggressive medial retraction, identify anatomical landmarks early before extensive dissection

Suprascapular Nerve

Location: Passes through suprascapular notch beneath superior transverse scapular ligament, then around lateral scapular spine to innervate infraspinatus. At risk with superior glenoid screws in RSA conversion. Protection: Superior baseplate screws directed anterosuperior toward coracoid (not posterosuperior), confirm screw length with fluoroscopy, use CT planning to assess bone corridors

Mnemonic

FAILUREFAILURE - Common Revision Indications

Mnemonic

EXTRACTEXTRACT - Component Removal Strategy

Indications for Revision Shoulder Arthroplasty

Primary Failure Modes

Critical Yield Data

Aseptic Loosening

Instability

Infection

Fracture

Aseptic Glenoid Loosening (Most Common)

Progressive radiolucent lines around glenoid component (>2mm, progressive)
Component migration or tilt on serial radiographs
Pain with activity (especially overhead use)
CT confirms bone loss pattern and extent

Aseptic Humeral Loosening (Less Common)

Radiolucent lines around humeral stem (complete circumferential)
Stem subsidence or varus/valgus tilt
Pain with arm rotation or loading
More common with uncemented stems in osteoporotic bone

Instability and Dislocation

Recurrent subluxation or dislocation episodes
Subscapularis failure (anterior instability most common)
Component malposition (excessive retroversion, superior tilt)
Glenoid bone loss creating rim instability
Rotator cuff failure (superior migration, anterior-superior escape)

Infection (Rule Out in All Cases)

Acute postoperative: wound drainage, fever, pain
Chronic low-grade: indolent pain, stiffness, minimal inflammation
Propionibacterium acnes (25-30% of infected revisions): slow-growing, minimal signs
Elevated inflammatory markers (ESR, CRP) - low sensitivity
Joint aspiration MANDATORY if any suspicion

Periprosthetic Fracture

Traumatic (fall) or atraumatic (stress fracture in osteoporotic bone)
Proximal humerus most common (metaphyseal bone loss)
Glenoid fracture rare but catastrophic
May occur intraoperatively during index procedure

Rotator Cuff Failure

Progressive superior migration (loss of acromiohumeral interval)
Subscapularis rupture (anterior instability, internal rotation loss)
Rotator cuff arthropathy pattern (Hamada classification progression)
Pseudoparalysis (inability to elevate arm)

Unexplained Pain with Well-Fixed Components

Most difficult indication - careful patient selection
Rule out: infection (aspiration, inflammatory markers), nerve injury (EMG), cervical spine pathology (MRI neck), complex regional pain syndrome, psychiatric factors
Poor outcomes if no mechanical etiology identified
Consider non-operative management, pain psychology

Preoperative Workup (MANDATORY Components)

Infection Evaluation (ALL Cases)

Serum inflammatory markers: ESR, CRP (low sensitivity - normal does not exclude infection)
Joint aspiration: cell count (>1,100 WBC/mm³ concerning, >3,000 likely septic), differential (>70% PMN concerning), Gram stain (low sensitivity), culture aerobic/anaerobic 14 days for P. acnes
Consider: synovial alpha-defensin, leukocyte esterase if aspiration equivocal
Review prior operative notes for infection history

Bone Stock Assessment (CT Mandatory)

CT shoulder with 3D reconstruction (thin cuts <2mm)
Assess glenoid bone loss pattern (central, peripheral, combined)
Classify glenoid deficiency: mild (<10mm depth), moderate (10-15mm), severe (>15mm or medial wall breach)
Evaluate humeral canal: diameter, cortical thickness, prior cement mantle
Plan component sizes and bone grafting strategy

Soft Tissue Evaluation

MRI or ultrasound: rotator cuff integrity (subscapularis, supraspinatus, infraspinatus)
Cuff tears indicate need for conversion to RSA in most cases
Deltoid function assessment (axillary nerve integrity essential)
Assess for adhesive capsulitis (passive ROM under anesthesia)

Previous Operative Records

Request all prior operative notes
Document: previous approach, component types/sizes, complications, infection history
Obtain implant stickers/details for planning extraction strategy
Review previous imaging to understand progression

Medical Optimization

Optimize bone health: calcium, vitamin D supplementation, consider DEXA scan
Smoking cessation mandatory (wound healing, infection risk)
Diabetic control (HbA1c <7%)
Nutritional status (albumin >3.5 g/dL, lymphocyte count >1,500)
Cardiac risk stratification if elderly or comorbid

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

EXAMINER

"A 68-year-old presents 5 years after primary TSA with progressive pain and clicking. Radiographs show radiolucent lines around the glenoid component. How would you manage this patient?"

EXCEPTIONAL ANSWER

This presentation suggests glenoid loosening, the most common indication for revision (40% of cases). My systematic approach: **IMMEDIATE ASSESSMENT:** 1. History: Pain pattern (mechanical vs constant), clicking/clunking (suggests loose component), function decline, previous surgical details 2. Examination: ROM (active/passive), stability testing, rotator cuff function (active elevation, external rotation strength), neurovascular status 3. Imaging review: Serial radiographs (progressive lucency >2mm, component migration/tilt), current functional status **RULE OUT INFECTION (MANDATORY):** Even with presumed aseptic loosening, must exclude infection: - Serum inflammatory markers: ESR, CRP (elevated in 50-60% of infections but not specific) - Joint aspiration: Cell count (>1,100 WBC concerning, >3,000 likely septic), differential (>70% PMN), Gram stain, culture aerobic/anaerobic 14 days for Propionibacterium acnes - Low threshold for aspiration - P. acnes presents as aseptic loosening in 25-30% **ADVANCED IMAGING:** - CT shoulder with 3D reconstruction (MANDATORY): Assess glenoid bone loss pattern and extent, classify deficiency (mild <10mm, moderate 10-15mm, severe >15mm), plan reconstruction strategy, evaluate humeral component position - MRI or ultrasound: Rotator cuff integrity (conversion to RSA if cuff failed), subscapularis status (affects surgical approach) **SURGICAL PLANNING:** If confirmed aseptic loosening with adequate bone stock and intact cuff: 1. Revision anatomic TSA: Component extraction, glenoid bone stock management (bone graft if moderate loss), long humeral stem if revising stem, subscapularis management 2. If rotator cuff deficient OR severe bone loss: Conversion to reverse TSA (60-70% of revisions now RSA - more forgiving of bone loss and cuff deficiency) **PATIENT COUNSELING:** - Revision has lower success than primary (pain relief 70-80% vs 90-95%, satisfaction 65-75% vs 85-95%) - Re-revision risk 10-20% at 5 years - Recovery longer (6-12 months to plateau) - ROM expectations lower than primary

VIVA SCENARIOStandard

EXAMINER

"You are revising a well-fixed cemented humeral stem. Describe your approach to safe component extraction."

EXCEPTIONAL ANSWER

Well-fixed cemented stem extraction is high-risk for iatrogenic fracture (5-15% intraoperative fractures in revision). My systematic approach prioritizes safety: **PREOPERATIVE PLANNING (ESSENTIAL):** 1. Review preoperative CT: Extent of cement mantle (length, thickness), cortical thickness (assess fracture risk, normal >4mm, concerning if <2mm), humeral canal diameter, bone quality assessment 2. Plan extraction strategy: Direct extraction if cement appears loose, humeral window osteotomy if well-fixed (lower threshold in osteoporotic bone), extended trochanteric osteotomy (ETO) if cement extends beyond deltoid insertion 3. Equipment preparation: Universal extractor/slap hammer, high-speed burrs (long carbide/diamond), flexible osteotomes, oscillating saw, cerclage cables and cables, strut allografts if thin cortex **INTRAOPERATIVE TECHNIQUE:** **STEP 1: Adequate Soft Tissue Release (PREVENTS FRACTURE)** - Complete 360° capsulectomy (inferior, posterior, rotator interval) - Free all adhesions (deltoid, capsule, scar) - Achieve atraumatic dislocation BEFORE extraction attempts - Inadequate release is leading cause of fracture **STEP 2: Attempted Direct Extraction (If Cement Appears Loose)** - Attach universal extractor to Morse taper - Apply steady AXIAL force with slap hammer (avoid eccentric leverage) - If resistant after 3-4 attempts: STOP (forced extraction causes fracture) - Proceed to humeral window **STEP 3: Humeral Window Osteotomy (PREFERRED FOR WELL-FIXED CEMENT)** Indications: Well-fixed cement, osteoporotic bone (thin cortex), multiple failed extraction attempts Technique: 1. Mark window: Anterior humeral shaft 2-3cm distal to pectoralis insertion, 8-12cm length (based on cement extent from CT), 2-3cm width (one-third circumference) 2. Create with oscillating saw: Four sides of rectangle, stay in anterior cortex only, remove as free bone piece 3. Remove cement under DIRECT VISION: High-speed burr to fragment cement, osteotomes to lever pieces, extract stem through window 4. Reconstruct: Replace bone window, fix with 2-3 cerclage cables, consider plate if cortex thin, strut allograft if cortex <2mm **STEP 4: Extended Trochanteric Osteotomy (If Cement Extends Distally)** Indications: Cement beyond deltoid insertion (cannot access with window), very long stem Technique: Similar to window but hinged laterally (maintains soft tissue), 10-18cm length, fix with 3-4 cables, protected rehabilitation **INTRAOPERATIVE FRACTURE MANAGEMENT (IF OCCURS):** 1. Recognize IMMEDIATELY (audible crack, visualize fracture) 2. Undisplaced: Cerclage cables, long cemented stem bypassing 2 cortical diameters 3. Displaced: ORIF with plate ± cables, long stem, protected rehabilitation 4. Document, inform patient postoperatively, adjust rehabilitation

VIVA SCENARIOStandard

EXAMINER

"When would you convert a failed anatomic TSA to reverse shoulder arthroplasty, and what are the key technical considerations?"

EXCEPTIONAL ANSWER

Conversion to RSA is now the most common revision strategy (60-70% of shoulder revisions). My approach to indication and technique: **INDICATIONS FOR CONVERSION (From Most to Least Common):** **1. ROTATOR CUFF DEFICIENCY (MOST COMMON - 50-60% of conversions)** - Subscapularis failure: Anterior instability, cannot repair (tissue quality poor, retracted, fatty infiltrated Goutallier grade 3-4) - Superior cuff failure: Pseudoparalysis, superior migration on radiographs (loss of acromiohumeral interval), irreparable tears - Combined cuff deficiency: Anterosuperior escape pattern - Rotator cuff arthropathy (Hamada classification): Acetabularization (grade 3-5) Rationale: Anatomic TSA REQUIRES intact cuff to function. RSA does not depend on cuff (deltoid-powered) **2. SEVERE GLENOID BONE LOSS (25-30%)** - Central erosion >15mm depth OR medial wall compromise - Insufficient bone stock for anatomic glenoid component fixation - Failed bone grafting attempts Rationale: RSA more forgiving of bone loss - medialized center of rotation reduces shear stress, baseplate fixation into scapular body possible with augments/long screws **3. MULTIPLE PRIOR REVISIONS (15-20%)** - Two or more failed anatomic revisions - Progressive bone loss with each revision - Compromised soft tissues Rationale: RSA provides more predictable outcomes than repeat anatomic revision, less dependent on bone stock and soft tissue quality **4. ELDERLY/LOW-DEMAND PATIENTS (10-15%)** - Age >75 years with any revision indication - Medical comorbidities - Low functional demands (ADLs only) Rationale: Simpler reconstruction, more predictable pain relief, lower revision rate **5. RECURRENT INSTABILITY (5-10%)** - Failed soft tissue repairs - Inadequate bone stock for stability Rationale: RSA inherently more stable than anatomic TSA (medialized center, constrained) **CONTRAINDICATIONS:** Absolute: - Deltoid dysfunction (axillary nerve palsy) - RSA cannot function without deltoid - Active infection - requires two-stage with spacer - Inadequate glenoid bone for baseplate fixation - may need staging with bone graft Relative: - Age <65 years (wear/loosening long-term) - High activity level (loosening risk) **KEY TECHNICAL CONSIDERATIONS:** **GLENOID BASEPLATE PLACEMENT (CRITICAL FOR FIXATION):** 1. Bone stock assessment: Preoperative CT for screw planning, intraoperative assessment after component removal 2. Baseplate position: Medialized at glenoid vault (best bone stock), neutral or 5-10° inferior tilt (AVOID superior tilt - scapular notching), flush with glenoid rim 3. Screw configuration (MINIMUM 3, PREFER 4): - Central screw: Into glenoid vault (primary fixation) - Superior screw: Into coracoid base or scapular spine (STRONGEST fixation point) - Inferior screw: Into scapular pillar - Anterior/posterior screws: Into scapular body 4. Screw length: Use longest possible without breaching far cortex (CT planning essential), fluoroscopy confirms trajectory and length 5. Augments for bone deficiency: Wedge augments for asymmetric defects, step augments for central defects, bone graft for large defects **HUMERAL COMPONENT:** 1. Stem selection: Long stem (150-200mm) in revision setting, bypass previous cement/defects by 2 cortical diameters, cemented fixation for immediate stability 2. Humeral offset/lateralization: Balance deltoid tension (too tight: stiffness, too loose: instability) 3. Neck-shaft angle: 135-155° options per deltoid tensioning 4. Version: 20-30° retroversion (neutral to subscapularis tendon if intact) **SOFT TISSUE MANAGEMENT:** - Subscapularis: Repair if possible (less critical for RSA than anatomic TSA), accept deficiency if poor tissue, consider pectoralis major transfer if young/active - Superior cuff: Usually deficient (reason for RSA), do not attempt impossible repair - Deltoid: PROTECT at all costs (cannot function without deltoid) **STABILITY ASSESSMENT:** - Test after component insertion: No anterior translation in adduction + internal rotation - Adjust: Glenosphere size (36-42mm), humeral offset, component position - Accept slight posterior translation (anterior critical) **OUTCOMES TO DISCUSS:** - Pain relief: 80-90% good/excellent - Function improvement: Forward elevation 100-120°, external rotation limited (20-30°) - Satisfaction: 75-85% - Complications: 20-25% (instability 5-10%, infection 5-10%, nerve injury 3-5%, scapular notching 30-50% radiographic but mostly asymptomatic)