Revision Total Shoulder Arthroplasty to Reverse TSA

Preoperative Assessment and Planning

Clinical Evaluation

Patient History

• Previous TSA indication and timeline - determine failure mechanism (rotator cuff tear, instability, loosening, infection, fracture)
• Current symptoms: pain severity (VAS), functional limitations (forward elevation, activities of daily living), instability episodes
• Infection history: previous wound complications, systemic infections, immunosuppression, diabetes control
• Medical optimization: cardiac clearance for beach chair position, anticoagulation management, osteoporosis treatment
• Deltoid function assessment: critical for reverse TSA success - test manual muscle strength, observe active elevation

Physical Examination

• Active ROM: forward elevation (average 60-80° pre-revision), external rotation at side, internal rotation (hand behind back level)
• Passive ROM: assess stiffness vs pseudoparalysis (passive full, active limited suggests rotator cuff deficiency)
• Deltoid function: palpate muscle bulk, test against resistance - ESSENTIAL for reverse TSA outcomes
• Subscapularis integrity: belly press test, lift-off test (often difficult in stiff shoulders)
• Neurovascular examination: axillary nerve (deltoid contraction, lateral arm sensation), overall upper extremity function
• Wound assessment: previous surgical scars, skin quality, soft tissue envelope

Imaging Protocol

Plain Radiographs

• True AP (Grashey view): glenoid bone stock, component loosening (radiolucent lines, migration), humeral subsidence
• Scapular Y lateral: anterior/posterior component position, glenoid version assessment
• Axillary lateral: glenoid bone stock, version, component position, humeral head subluxation/dislocation
• Assess for: glenoid loosening (progressive radiolucent lines, migration), humeral stem loosening, osteolysis, fracture, heterotopic ossification

CT Scan with 3D Reconstruction (MANDATORY)

• Glenoid bone stock assessment using Sirveaux/Nerot classification (E0-E4)
• Anterior and posterior column integrity - critical for baseplate screw fixation
• Superior pillar and inferior pillar assessment for peripheral screw options
• Measure glenoid version: normal 2-10° retroversion, excessive retroversion common in failed TSA
• Humeral bone stock: canal diameter, cortical thickness, previous screw holes, cement extent if cemented
• 3D reconstruction for surgical planning: baseplate size, screw trajectory planning, bone graft needs

MRI (If Concern for Infection or Soft Tissue Assessment)

• Rotator cuff status: subscapularis, supraspinatus, infraspinatus, teres minor integrity
• Deltoid muscle quality: atrophy, fatty infiltration (Goutallier classification)
• Soft tissue edema, fluid collections concerning for infection
• Labral remnants, capsular integrity for reconstruction planning

Laboratory Workup

• Inflammatory markers if any infection concern: ESR (>30mm/hr concerning), CRP (>10mg/L concerning)
• Complete blood count: white blood cell count elevation concerning for infection
• Consider aspiration if elevated inflammatory markers: cell count (>3000 concerning), PMN% (>80% concerning), culture
• Medical clearance: CBC, basic metabolic panel, cardiac evaluation for beach chair position

Classification System - Sirveaux/Nerot Glenoid Bone Loss

E0: Intact Glenoid

• No erosion, preserved bone stock
• Management: Standard baseplate, central compression screw, 3-4 peripheral screws
• Excellent prognosis for durable fixation

E1: Central Erosion Minimal

• Central defect <2mm depth
• Columns and periphery intact
• Management: Standard baseplate with central compression screw
• May need slightly smaller baseplate for optimal contact

E2: Central Erosion Moderate

• Central defect 2-5mm depth
• Peripheral rim preserved
• Management: Standard baseplate, consider posterior bone graft for support
• Ensure adequate peripheral screw purchase into columns

E3: Posterior Erosion Significant

• Posterior defect >5mm depth
• Altered glenoid version (excessive retroversion)
• Management: BIO-RSA technique - posterior bone graft behind baseplate to restore version and increase contact area
• Morselized autograft (humeral head) or allograft, compressed by baseplate creating 'autograft effect'

E4: Massive Bone Loss

• Extensive central and/or peripheral defects
• Column compromise possible
• Management: May require structural allograft, custom augmented baseplate, or smaller baseplate with extensive grafting
• Consider higher failure risk - counsel patient appropriately

Surgical Planning Checklist

Implant Options Prepared

• Reverse TSA system: multiple baseplate sizes (25mm, 29mm, 33mm), glenosphere options (36mm, 40mm standard vs lateralized)
• Humeral stems: revision lengths, various diameters, cemented vs cementless options
• Polyethylene liner thickness: 6mm, 9mm, 12mm, 15mm for stability adjustment
• Metal augments if needed for bone loss reconstruction

Bone Graft Preparation

• Autograft: humeral head from removed components (morselized for glenoid, structural for humerus)
• Allograft availability: cancellous chips for glenoid, structural allograft for massive defects
• Bone graft preparation equipment: rongeurs, bone mill for morselization

Extraction and Revision Instruments

• Humeral component extraction: universal extraction system, curved osteotomes, flexible osteotomes
• Cement removal: high-speed burr, hand instruments, ultrasonic cement removal device
• Glenoid component removal: curved explant osteotomes, thin flexible osteotomes
• Extended trochanteric osteotomy equipment: oscillating saw, cables/wires for fixation
• C-arm fluoroscopy if available for screw trajectory confirmation

Anticipated Surgical Time

• Standard revision: 90-120 minutes
• Complex revision with ETO, significant bone loss: 120-180 minutes
• Factor additional time for: well-fixed component extraction, extensive cement removal, bone grafting

Surgical Anatomy and Approach

Surface Anatomy and Landmarks

Bony Landmarks

• Acromion: lateral edge, anterior border, posterolateral corner - reference for incision and axillary nerve location
• Clavicle: medial border defines deltopectoral interval superiorly
• Coracoid process: palpable 2cm below clavicle at deltopectoral interval - reference for musculocutaneous nerve (5-8cm distal to tip)
• Acromioclavicular joint: useful landmark for superior extent of exposure

Neurovascular Structures at Risk

Axillary Nerve

• Course: exits quadrangular space with posterior humeral circumflex artery, wraps around surgical neck of humerus
• Location: 5-7cm below acromion anteriorly (range 3-10cm), crosses inferior border of subscapularis
• At risk: inferior subscapularis/capsular release, anteroinferior retractor placement, humeral manipulation
• Protection: blunt retractors only below acromion, gentle inferior release from lateral to medial, limit retraction depth to <7cm

Musculocutaneous Nerve

• Course: branches from lateral cord of brachial plexus, enters coracobrachialis muscle
• Location: enters coracobrachialis 5-8cm (range 3-12cm) distal to coracoid tip
• At risk: medial retraction of conjoint tendon, aggressive subscapularis releases
• Protection: identify nerve before extensive releases, limit medial retraction force and duration

Brachial Plexus

• Location: medial to operative field in axilla
• At risk: excessive or prolonged medial retraction, poor patient positioning causing traction
• Protection: proper positioning with arm support, gentle retraction, periodic retractor relaxation

Cephalic Vein

• Course: runs in deltopectoral interval, variable anatomy (lateral vs medial vs bifid)
• At risk: initial deltopectoral interval development
• Protection: identify early, take laterally with deltoid (better healing, preserves drainage) or medially with pectoralis (preserves vein)

Deltopectoral Approach

Incision

• Utilize previous deltopectoral incision in most cases
• Extend proximally if needed: 2-3cm above clavicle for superior glenoid exposure
• Extend distally if needed: 10-12cm down arm for humeral component extraction, cement removal, or extended trochanteric osteotomy
• Mark incision with patient upright if possible to assess cosmetic positioning

Interval Development

• Identify deltopectoral interval by palpation: depression between deltoid (lateral) and pectoralis major (medial)
• Locate cephalic vein in interval - variable position (35% lateral, 40% medial, 25% bifid)
• Take vein laterally with deltoid (preserves drainage, better deltoid healing) or medially with pectoralis (vein preservation)
• Sharp dissection through subcutaneous tissue to deltoid and pectoralis fascia
• Blunt dissection to develop interval - finger sweep to break adhesions from previous surgery
• Place self-retaining retractor (Kolbel, Browne) to maintain deltopectoral interval

Deep Exposure

• Identify clavipectoral fascia lateral to conjoint tendon (coracobrachialis and short head biceps)
• Tag clavipectoral fascia with suture or clamp for later repair
• Incise clavipectoral fascia 1cm lateral to conjoint tendon to avoid musculocutaneous nerve
• Identify and protect musculocutaneous nerve: enters coracobrachialis 5-8cm below coracoid tip
• Avoid aggressive medial retraction of conjoint tendon to prevent nerve injury

Extensile Exposure Options

Superior Extension

• Indication: difficult glenoid exposure, superior glenoid bone loss, need for superior baseplate screw placement
• Technique: extend incision above clavicle, release deltoid from anterior clavicle with tagged sutures for repair
• Risk: deltoid denervation if extend too far laterally (preserve anterior deltoid nerve branches)

Inferior Extension

• Indication: humeral component extraction, cement removal, extended trochanteric osteotomy
• Technique: extend incision 10-15cm down arm, develop plane between deltoid and brachialis
• Protection: axillary nerve at highest risk - stays with deltoid, avoid periosteal stripping of proximal humerus

Three-Retractor Technique for Glenoid Exposure

Anteroinferior Retractor (Fukuda or Darrach)

• Position: along anterior glenoid rim, gentle traction inferiorly and medially
• Purpose: displaces humeral head anteriorly and inferiorly, exposes glenoid face
• Danger: axillary nerve injury if placed >7cm below acromion or excessive force applied
• Safety: blunt retractor tip, place along bone (not soft tissue), gentle gradual traction

Anterosuperior Retractor (Blunt Hohmann)

• Position: over coracoid base superiorly, lifts conjoint tendon
• Purpose: retracts superior soft tissues, improves superior glenoid visualization
• Danger: musculocutaneous nerve if retractor slips medially
• Safety: secure placement on bone, assistant maintains retractor position

Posterior Retractor (Blunt Hohmann)

• Position: behind glenoid, placed after capsulectomy
• Purpose: critical for posterior glenoid visualization - allows assessment of bone stock, baseplate positioning
• Danger: suprascapular nerve posterosuperiorly, circumflex scapular vessels inferiorly
• Safety: stay on bone, avoid soft tissue retraction, place under direct vision

Lighting for Glenoid Visualization

• Headlamp mandatory for all shoulder arthroplasty - critical for posterior glenoid visualization
• Adjust patient position and retractors to optimize light angle onto glenoid
• Assistant headlamp helpful for dual illumination

Detailed Operative Technique

Step 1: Preoperative Planning and Preparation

Imaging Review Review preoperative CT scan with 3D reconstruction to assess glenoid bone stock using Sirveaux/Nerot classification (E0-E4 glenoid erosion). Identify previous operative approach from notes and scars. Plan reconstruction strategy: standard baseplate for E0-E2, BIO-RSA (bone graft augmentation) for E3, custom components/bone graft for E4. Assess rotator cuff status on MRI - subscapularis integrity particularly important. Verify deltoid function clinically. Templating for component size and position. Have full revision tray available including metal augments, bone graft options, cables/wires for trochanteric osteotomy if needed, and extraction instruments for well-fixed components.

Step 2: Patient Positioning and Draping

Positioning Beach chair position with back at 30-45 degrees. Head secured in neutral with slight extension using well-padded headrest. Arm free to move through full range of motion - use arm holder or sterile assistant. Mark anatomic landmarks: acromion, clavicle, coracoid, previous incision. Wide preparation from midline medially to posterior scapula, from base of neck to mid-humerus. Ensure C-arm access if intraoperative imaging needed for baseplate screw placement. Position Mayo stand over abdomen for arm rest during procedure.

Step 3: Approach and Initial Exposure

Deltopectoral Interval Incise through previous deltopectoral scar - typically starts 2cm lateral to coracoid and extends 12-15cm distally. Identify cephalic vein in deltopectoral interval - take laterally with deltoid (better healing) or medially with pectoralis (preserves vein). Carefully mobilize deltoid laterally and pectoralis medially through scar tissue using combination of sharp and blunt dissection. Place Kolbel or blunt retractors to maintain interval. Palpate for deltoid dehiscence from previous surgery - repair any defects at closure. Tag clavipectoral fascia and incise lateral to conjoint tendon. Identify and protect musculocutaneous nerve (enters coracobrachialis 5-8cm below coracoid) - avoid excessive medial retraction.

Step 4: Subscapularis Assessment and Management

Subscapularis Evaluation Identify subscapularis or remnants from previous surgery. In revision cases, subscapularis may be: (1) previously repaired and intact, (2) attenuated/deficient, (3) completely absent, or (4) scarred to anterior capsule. If subscapularis present: carefully develop plane between subscapularis and anterior capsule using blunt dissection and electrocautery. Tag with heavy braided sutures (#2 Ethibond) for later repair. If deficient: plan conjoint tendon transfer or pectoralis major transfer for anterior stability. Preserve long head biceps if intact (provides some anterior stability) or tenotomize if frayed/degenerated. Release inferior subscapularis carefully to protect axillary nerve (5-7cm below acromion).

Step 5: Humeral Component Exposure and Extraction

Component Removal Externally rotate and extend arm to deliver proximal humerus into wound. Remove any heterotopic ossification with rongeurs/osteotomes. Perform anterior capsulectomy to expose humeral component. Assess stem fixation - loose vs well-fixed determines extraction technique. For LOOSE stem: use curved osteotomes at bone-implant interface working circumferentially, gentle extraction devices. For WELL-FIXED stem: may require extended trochanteric osteotomy (ETO) or humeral window osteotomy for cement removal. ETO technique if needed: mark osteotomy line 12-15cm along lateral humerus preserving vastus lateralis insertion, create controlled fracture with osteotomes, hinge open preserving soft tissue envelope. Remove stem using extraction devices - universal extraction systems attach to Morse taper. For cemented stems: remove all cement using high-speed burr, hand instruments, ultrasonic cement removal tools - critical to reach pristine bleeding bone.

Step 6: Glenoid Component Exposure

Glenoid Visualization Circumferential release of anterior, inferior, and posterior capsule from glenoid rim using electrocautery and elevator. Place Fukuda or glenoid retractors: anteroinferior retractor (protect axillary nerve), anterosuperior retractor over coracoid base, posterior retractor behind glenoid. Release rotator cuff remnants from greater tuberosity to improve glenoid visualization. Remove any remaining labrum/soft tissue from glenoid face. Identify anatomic landmarks: anterosuperior/inferior quadrants, bare area centrally, coracoid base superiorly. Use headlamp and assistant retraction for optimal visualization of posterior glenoid. Assess bone stock - palpate columns, walls, and central glenoid.

Step 7: Glenoid Component Removal

Explantation Technique Remove polyethylene liner first if metal-backed glenoid. For cemented all-poly glenoid: use high-speed burr to thin cement mantle, curved osteotomes at bone-cement interface working from periphery to center, careful extraction avoiding glenoid fracture. For cementless metal-backed glenoid: remove screws first (may be stripped - use screw extractors), use curved explant osteotomes at bone-implant interface starting anterosuperiorly and working circumferentially, gentle rocking motion to break ingrowth interface. Use flexible osteotomes and curettes to remove cement from glenoid face. Pulsatile lavage to clear debris. Send multiple tissue samples (minimum 5) for culture to rule out occult infection. Assess bone stock after component removal - often worse than preoperative CT suggested.

Step 8: Glenoid Bone Stock Assessment and Reconstruction Planning

Sirveaux Classification Application Assess bone defects using Sirveaux classification: E0 (intact), E1 (central erosion minimal), E2 (central erosion moderate less than 5mm), E3 (posterior erosion greater than 5mm), E4 (massive bone loss). Palpate glenoid columns and walls - anterior column, posterior column, superior pillar, inferior pillar. Measure bone loss with calibrated instruments. Plan reconstruction: TYPE E0-E1: standard baseplate with compression screw and peripheral screws; TYPE E2: standard baseplate, may need posterior bone graft for support; TYPE E3: BIO-RSA technique - posterior bone graft behind baseplate to restore version and increase contact area; TYPE E4: may need custom implant, structural allograft, or bone graft with smaller baseplate. Prepare bone graft if needed - autograft from humeral head or allograft cancellous chips morselized.

Step 9: Glenoid Baseplate Preparation and Insertion

Baseplate Fixation Determine baseplate position: inferiorly positioned (lower half of glenoid), 10-15 degrees inferior tilt to reduce scapular notching, maximize screw fixation into scapular spine and pillars. Use glenoid guide pin for central screw - aim perpendicular to glenoid face toward scapular spine/body junction. Confirm position with fluoroscopy if available. Ream glenoid face to create flat surface for baseplate contact - reaming depth 2-3mm to bleeding subchondral bone, preserve columns and walls. Trial baseplate to confirm fit, assess contact area (greater than 70% contact optimal). For BIO-RSA: pack morselized bone graft posterior to baseplate before final insertion. Insert baseplate using compression screw first (6.5mm central screw aimed at scapular spine/body junction for maximum purchase), then peripheral locking screws (typically 2-4 screws into superior pillar, anterior column, or posterior column). Aim screws to engage strongest bone: superior pillar (superiorly), scapular spine (posterosuperiorly), coracoid base (anterosuperiorly). Verify all screws have good purchase - no toggling. Final baseplate stability check - should be rock-solid.

Step 10: Glenosphere Assembly and Attachment

Glenosphere Configuration Select glenosphere size: 36mm or 40mm diameter (larger equals more deltoid tension, less notching, but increased joint forces). Select glenosphere lateralization: standard (0mm), lateralized +4mm (BIO-RSA or increased deltoid tension). Lateralized glenospheres increase deltoid moment arm, improve ROM and strength, but increase shear forces on baseplate. Clean baseplate Morse taper thoroughly. Attach glenosphere to baseplate using manufacturer's specific technique - typically Morse taper with locking screw mechanism. Ensure secure seating with firm impaction. Verify glenosphere position: eccentric inferior to maximize inferior ROM, avoid superior overhang which limits abduction. Trial ROM with trial humeral components.

Step 11: Humeral Canal Preparation

Stem Preparation Prepare humeral canal using sequential broaches or reamers per implant system. Goal: achieve stable fixation of humeral stem (metaphyseal fit for cementless, cement mantle space for cemented). For cementless stem: broach to final size achieving press-fit in metaphysis, ensure no toggle or subsidence. For cemented stem: broach 1-2 sizes under-reamed to create space for 2-3mm cement mantle. Assess stem version: 20-30 degrees retroversion referenced off forearm with elbow 90 degrees. Version guide on broach/implant helps. Mark version on proximal humerus to maintain during final implant insertion. Prepare proximal humerus for humeral component seating - ensure flat surface, remove osteophytes. Consider bone graft of any humeral defects from previous screw holes or fractures. Pulse lavage canal thoroughly, dry canal if cementing.

Step 12: Trial Reduction and Assessment

Stability Testing Insert trial humeral stem at planned version (20-30° retroversion). Select trial polyethylene insert thickness: options typically 6mm, 9mm, 12mm, 15mm. Start with thinnest and assess stability. Reduce trial components. Assess stability through range of motion: internal rotation, external rotation, abduction, forward elevation, combined motions. Stability criteria: no subluxation with arm at side in internal rotation (most unstable position for reverse TSA), stable through full ROM, firm endpoint with stress testing. Assess soft tissue tension: should feel moderate tension, not too tight (limits ROM) or too loose (unstable). Check ROM: forward elevation greater than 130°, external rotation 30-40°, internal rotation to sacrum optimal. Assess impingement: arm at side, combined extension-adduction-IR should not cause anterior impingement. If unstable: increase poly thickness, check component position (glenosphere too superior, humeral component malversion common causes), consider lateralized glenosphere. If limited ROM: ensure adequate soft tissue releases, check for impingement, consider larger glenosphere.

Step 13: Final Component Implantation

Definitive Fixation Remove trial components. Pulse lavage all surfaces. For CEMENTED humeral stem: insert distal cement restrictor, vacuum mix polymethylmethacrylate cement (consider antibiotic-loaded if concerned about infection), use cement gun for retrograde insertion, pressurize cement, insert stem in correct version (20-30° retroversion), maintain position during polymerization (3-5 minutes), remove excess cement. For CEMENTLESS stem: irrigate canal, ensure dry, insert stem with firm impaction achieving press-fit, verify version with forearm reference, confirm no subsidence. Insert final polyethylene liner onto humeral component - ensure proper seating with snap/lock mechanism per implant design. Select final poly thickness based on trials (typically 6-12mm). Reduce components with gentle traction and rotation. Verify stability identical to trials. Remove all retractors. Inspect for retained instruments/sponges.

Step 14: Subscapularis Repair and Soft Tissue Closure

Tendon Reconstruction Subscapularis repair if any viable tissue available - significantly improves stability and internal rotation. Technique: arm in neutral rotation, gentle tension on subscapularis, repair to lesser tuberosity using: (1) transosseous sutures through bone tunnels (#2 non-absorbable), (2) suture anchors in tuberosity, or (3) direct repair to capsule if tuberosity bone poor quality. If subscapularis deficient: consider pectoralis major transfer for anterior stability (transfer along conjoint tendon, attach to lesser tuberosity). If subscapularis irreparable: counsel patient on limited internal rotation and higher instability risk. Repair extended trochanteric osteotomy if performed: reduce fragment, fix with 2-3 cables around humerus, ensure stable fixation. Irrigate wound copiously with 3-6 liters saline (antibiotic irrigation controversial, not routine). Inspect for hemostasis - meticulous cautery to prevent hematoma. Close clavipectoral fascia with absorbable sutures. Repair deltoid to pectoralis major if split extended. Close subcutaneous tissue in layers with absorbable sutures. Skin closure per surgeon preference (subcuticular, staples, or nylon sutures). Sterile dressing and sling application.

Step 15: Postoperative Management and Rehabilitation Protocol

Recovery Protocol Immediate postoperative: sling immobilization with arm in neutral rotation, ice therapy for pain and swelling, neurovascular checks hourly x4 then q4h x24 hours. Pain management: multimodal analgesia (regional block if placed, oral opioids, NSAIDs, acetaminophen). DVT prophylaxis per protocol (mechanical compression, aspirin 81-325mg daily, or pharmacologic anticoagulation per patient risk). Antibiotics: cefazolin 1-2g (or vancomycin if MRSA risk) for 24 hours per institutional protocol. Immediate radiographs: true AP and scapular Y views to confirm component position. REHABILITATION PROTOCOL with subscapularis repair: Week 0-6 sling immobilization with gentle passive ROM starting week 2 (forward elevation, external rotation with arm at side, NO internal rotation), week 6-8 sling discontinuation and active ROM begins, week 8-12 progressive strengthening, week 12+ unrestricted activity as tolerated. WITHOUT subscapularis repair: earlier mobilization acceptable (passive ROM immediate, active ROM week 3-4). Avoid pushing, pulling, lifting greater than 5 pounds x 3 months. Follow-up: 2 weeks (wound check), 6 weeks (radiographs, advance PT), 3 months, 6 months, annually. Monitor for complications: infection (wound drainage, fever), instability (recurrent subluxation/dislocation), stiffness (persistent limited ROM), nerve injury (deltoid weakness from axillary nerve, IR weakness from musculocutaneous nerve).

Complications: Recognition and Management

Additional Complications

Hematoma (2-3%)

• Recognition: excessive postoperative swelling, wound drainage, ecchymosis, wound tension
• Prevention: meticulous intraoperative hemostasis, avoid anticoagulation immediately postoperatively, maintain compression dressing
• Management: small hematoma - observation; large/expanding hematoma - return to OR for evacuation to prevent infection and stiffness

Component Dissociation (rare less than 1%)

• Glenosphere dissociation from baseplate: Morse taper failure or locking screw breakage
• Polyethylene dissociation from humeral component: inadequate locking mechanism engagement
• Prevention: verify secure seating, proper impaction, locking mechanism engaged per manufacturer protocol
• Management: requires reoperation for component exchange, assess why dissociation occurred

Stiffness (5-10%)

• Persistent limited ROM despite appropriate PT, often multifactorial (scar tissue, heterotopic ossification, patient factors)
• Prevention: early appropriate ROM protocol per subscapularis status, PT compliance, treat heterotopic ossification risk factors (burns, head injury, ankylosing spondylitis) with indomethacin
• Management: manipulation under anesthesia if severe and early (less than 3 months), arthroscopic or open capsular release for late stiffness

Evidence-Based Outcomes and Registry Data

Australian Registry Data (AOANJRR)

Survival Rates for Reverse TSA Revision

• 5-year survival rate: 85-90% (primary reverse TSA: 92-94%)
• 10-year survival rate: 80-85% (primary reverse TSA: 88-90%)
• Main failure mode: baseplate loosening (40%), infection (25%), instability (15%), fracture (10%)
• Younger patients (less than 65 years) have higher revision rates due to increased activity and longer follow-up

Indications for Revision to Reverse TSA

• Rotator cuff deficiency with failed anatomic TSA: most common, excellent outcomes
• Glenoid loosening: good outcomes if bone stock adequate for baseplate fixation
• Instability: variable outcomes depending on soft tissue quality
• Periprosthetic fracture: acceptable outcomes with appropriate fracture management
• Infection: lower success rates, two-stage protocol improves outcomes

Factors Affecting Outcomes

• Glenoid bone stock: E0-E2 best outcomes, E3 good with BIO-RSA, E4 higher failure risk
• Subscapularis integrity: repair significantly improves stability and internal rotation
• Deltoid function: essential for success - assess preoperatively, protect intraoperatively
• Patient age: younger patients higher expectations but increased revision risk over time
• Number of previous surgeries: each revision decreases survival and outcomes

Functional Outcomes After Revision to Reverse TSA

Range of Motion Improvements

• Forward elevation: preoperative average 60-80° → postoperative 120-140° (significant improvement)
• External rotation: generally maintained at 30-40° (sometimes limited by subscapularis scarring)
• Internal rotation: variable, depends on subscapularis status - with repair average sacrum level, without repair L3-L5 level
• Abduction: improved to 100-120° in most patients (deltoid-powered motion)

Pain Relief and Function

• Pain relief: excellent in 85-90% of patients using VAS improvement
• Patient satisfaction: high in 80-85% despite ROM limitations compared to primary reverse TSA
• Activities of daily living: significant improvement in combing hair, reaching overhead shelves, personal hygiene
• American Shoulder and Elbow Surgeons (ASES) score: improves from average 35-45 preop to 65-75 postop
• Constant-Murley score: improves from 30-40 to 55-65 (lower than primary due to revision setting)

Biomechanical Principles - Grammont Design

Medialized Center of Rotation

• Glenosphere placed at glenoid face (medial) increases deltoid moment arm by moving fulcrum medially
• Increased moment arm reduces force needed for deltoid to elevate arm
• Reduces joint reaction forces on glenoid by approximately 30% compared to anatomic TSA
• Disadvantage: increases scapular notching risk (addressed by inferior positioning and tilt)

Distalized Humerus

• Humeral component sits distal to anatomic position, increasing deltoid tension
• Pre-tensions deltoid, improving force generation across ROM
• Compensates for loss of rotator cuff compressive force
• Creates stable fulcrum allowing deltoid to function as primary elevator

Semiconstrained Design

• Fixed fulcrum at glenosphere-polyethylene articulation provides inherent stability
• Less dependent on soft tissue balancing than anatomic TSA
• Allows function despite rotator cuff deficiency
• Trade-off: higher component stresses, particularly baseplate shear forces

Modern Modifications - Lateralization

BIO-RSA Technique (Bone Increased Offset)

• Posterior bone graft behind baseplate for E3 glenoid defects
• Advantages: restores glenoid version, increases glenoid-baseplate contact area, lateralizes center of rotation
• Lateralization benefits: increased deltoid moment arm, reduced scapular notching, improved ROM and strength
• Technique: morselized cancellous graft packed posterior to glenoid, baseplate compressed creating autograft effect
• Outcomes: similar survival to standard reverse TSA with better ROM in E3 defects

Lateralized Glenosphere Designs

• Eccentric glenosphere (+4mm to +10mm lateral offset)
• Increases deltoid moment arm similar to BIO-RSA
• Reduces scapular notching by moving center of rotation laterally
• Disadvantage: increases shear stress on baseplate - requires excellent bone stock and screw fixation
• Best for: patients with adequate bone stock, higher functional demands, desire for better ROM

Complications - Evidence-Based Rates

Revision Reverse TSA Complication Rates

• Infection: 1-3% (higher than primary 0.5-1.5%)
• Instability: 5-10% (lower than anatomic TSA 15-30%, higher than primary reverse 2-5%)
• Scapular notching: 30-60% radiographic (reduced to 20-30% with modern techniques)
• Baseplate loosening: 3-5% at 5 years (1-2% for primary reverse TSA)
• Nerve injury: less than 1% (axillary nerve most common)
• Acromial fracture: 2-4% (unique to reverse TSA)
• Periprosthetic fracture: 1-3% intraoperative, 2-3% postoperative

Factors Reducing Complications

• Inferior glenoid positioning: reduces notching from 60% to 20-30%
• Subscapularis repair: reduces instability by 30-40%, improves internal rotation 10-15°
• Adequate baseplate screws (minimum 4): reduces loosening risk
• Proper version (20-30° retroversion): optimizes stability and ROM
• High-volume surgeon (greater than 25 reverse TSA per year): reduces complications 20-30%

Cost-Effectiveness

Economic Analysis

• Revision shoulder arthroplasty costs 1.5-2x primary arthroplasty due to longer operative time, revision implants, potential complications
• Reverse TSA for revision more cost-effective than repeat anatomic TSA due to lower re-revision rates
• Successful revision provides significant QALY (quality-adjusted life year) improvement
• Cost per QALY well within acceptable thresholds (under AUD $50,000 per QALY in Australian healthcare system)