High Yield Overview

ANATOMIC TOTAL SHOULDER ARTHROPLASTY

Deltopectoral approach | advanced

Critical Danger Structures

Axillary Nerve

Location: Exits quadrilateral space posteriorly, crosses inferior glenohumeral joint capsule 5-7mm inferior to glenoid rim, runs on deep surface of deltoid muscle at level of surgical neck

Protection: Limit inferior retraction to less than 1cm, stay on bone during inferior capsular release with curved osteotome, avoid prolonged retraction, gentle tissue handling during humeral dislocation

Musculocutaneous Nerve

Location: Enters conjoint tendon (coracobrachialis and short head biceps) 3-8cm distal to coracoid tip (mean 5.5cm), can enter as proximal as 2cm in anatomic variants

Protection: Never place retractor medial to conjoint tendon, identify conjoint before retraction, limit medial retraction force and duration (less than 90 minutes continuous), retract conjoint as unit not individually

Cephalic Vein

Location: Runs in deltopectoral interval within fatty triangle, variable anatomy (bifurcation in 15%, large tributaries in 30%), connects to axillary vein superiorly

Protection: Identify early during interval development, retract laterally with deltoid (85%) or medially with pectoralis (15%), if injured ligate proximally and distally (not just cautery), preservation preferred but sacrifice acceptable if needed for exposure

Brachial Plexus and Axillary Vessels

Location: Deep and medial to surgical field, posterior to pectoralis minor, anterior to subscapularis muscle, within 2-3cm of surgical plane at glenoid exposure

Protection: Never retract medial to conjoint tendon, limit depth of glenoid drilling (vault depth 25-30mm average, check preoperative CT), avoid excessive medial retraction during glenoid exposure, use depth gauge before drilling

Radial Nerve

Location: Spirals around posterior humerus in spiral groove 14-20cm distal to acromion (average 16cm), at risk during distal humeral canal preparation and retractor placement

Protection: Limit humeral canal reaming depth to 10-15cm maximum, avoid lateral retractors on distal humerus, gentle technique during stem insertion, awareness of course prevents injury during revision or exposure extension

Mnemonic

GLENOIDGLENOID Positioning Principles

Memory Hook:Glenoid component malposition is the leading cause of early loosening and failure. Examiners expect detailed knowledge of Walch classification and correction strategies for abnormal version and bone loss.

Mnemonic

SUBSCAPSUBSCAP Repair Principles

Memory Hook:Subscapularis is the most critical soft tissue structure in anatomic TSA. Lesser tuberosity osteotomy allows strongest repair with best healing rates. Examiners expect comparison of repair techniques and outcomes data.

Walch Glenoid Classification

Clinical Significance: Describes glenoid morphology in primary osteoarthritis based on shape, version, and humeral head position - guides surgical strategy for glenoid preparation and component selection.

Type A: Concentric (Centered Humeral Head)

A1 - Minor Erosion: Centered humeral head with minor central erosion, normal or slight posterior wear, version typically less than 10° retroversion. Management: Standard concentric reaming, standard all-polyethylene component, excellent outcomes.

A2 - Major Central Erosion: Centered humeral head with major central erosion creating deep concavity, maintained version less than 10°. Management: May require deeper reaming to achieve flat surface, risk of excessive bone loss and medialization, consider augmented components if bone stock insufficient.

Type B: Eccentric (Posterior Subluxation)

B1 - Narrowed Posterior Joint Space: Asymmetric posterior wear with biconcave appearance, less than 70% posterior subluxation, retroversion typically 10-15°. Management: Eccentric reaming (high-side reaming) to correct version, aim for neutral to 5° retroversion final position.

B2 - Posterior Subluxation: Biconcave glenoid with greater than 70% posterior subluxation, retroversion 10-20°, posterior humeral head erosion. Management: Eccentric reaming if bone stock adequate (can correct up to 15° version), consider posterior augmented components or bone grafting if excessive bone loss, may require CT-based planning and patient-specific instrumentation.

B3 - Monoconcave Posterior Defect: Posterior bone loss creating monoconcave appearance, retroversion greater than 25°, severe posterior humeral head subluxation. Management: Eccentric reaming often insufficient (risks vault perforation), posterior bone grafting (autograft from humeral head or allograft), augmented components, or consider reverse TSA if cuff compromise develops.

Type C: Dysplastic

Glenoid Dysplasia: Retroversion greater than 25° with dysplastic anatomy, biconcave or monoconcave morphology, often congenital or developmental. Management: Complex reconstruction, often requires bone grafting, augmented components, or reverse TSA. Anatomic TSA outcomes inferior - consider alternative strategies.

Surgical Decision Algorithm

Retroversion less than 10°: Standard concentric reaming, all-polyethylene component.

Retroversion 10-20°: Eccentric reaming (high-side) to correct version, monitor bone stock, acceptable to leave 5-10° retroversion if bone preservation needed.

Retroversion greater than 20°: Bone grafting (structural autograft or allograft), augmented/stepped components, or consider reverse TSA if cuff questionable.

Key Exam Point: Examiners expect detailed knowledge of classification, ability to identify types on radiographs/CT, and articulate management strategy for B2/B3 glenoids including alternative options and expected outcomes.

Positioning and Preparation

Patient Position: Beach chair position 30-45° upright, head secured in Mayfield or horseshoe headrest (prevent intraoperative movement), bump under medial scapula for glenoid exposure (improves access to posterior glenoid), arm free-draped allowing full mobility, table articulation to upright position optimizes glenoid visualization.

Surgical Approach: Deltopectoral approach - gold standard internervous interval for anatomic TSA, provides excellent humeral and glenoid exposure, minimal muscle denervation risk.

Incision: Curvilinear incision 12-15cm from coracoid to deltoid insertion, start 2cm lateral and 2cm inferior to coracoid tip (avoids coracoid stress fracture from retractor pressure), curve distally following deltopectoral groove to end 4cm distal to anterior axillary crease, landmarks palpable before incision.

Anesthesia: General anesthesia with controlled hypotension (reduces bleeding, improves visualization), interscalene block for postoperative analgesia (caution - phrenic nerve palsy in 5%, avoid bilateral blocks), short-acting paralysis allows neuromonitoring if available.

Antibiotics: Cefazolin 2g IV within 60 minutes before incision (vancomycin 15mg/kg if penicillin allergy or MRSA risk), redose cefazolin every 4 hours intraoperatively if case exceeds duration, continue 24 hours postoperatively (single dose adequate per guidelines but institutional variation).

Operative Technique

Step 1: Skin incision from coracoid to deltoid insertion (12-15cm)

Skin incision from coracoid to deltoid insertion (12-15cm): Start 2cm lateral and 2cm inferior to coracoid tip, curve distally following deltopectoral groove to end 4cm distal to anterior axillary crease. EXAM KEY: Mark incision with patient upright to account for soft tissue shift when supine/beach chair. Avoid extending too far medially (cephalic vein injury) or laterally (deltoid denervation). Incision length must allow glenoid exposure without excessive retraction - too short causes soft tissue trauma and poor visualization.

Exam Pearl

Technical Tip: EXAM KEY: Incision length directly affects visualization and soft tissue trauma. 12cm minimum for primary TSA in average build, 15cm for muscular patients or revision surgery. Confirm anatomical landmarks palpable before incising - coracoid tip, deltopectoral groove, anterior axillary crease.

Dangers at this step

Skin necrosis from excessive tension if incision too short
Cephalic vein injury if incision too medial
Deltoid denervation if incision extends too lateral
Inadequate exposure if incision length insufficient

Step 2: Identify and protect cephalic vein - retract laterally with deltoid

Identify and protect cephalic vein - retract laterally with deltoid: Develop subcutaneous flaps sharply to expose deltopectoral interval. Identify cephalic vein running in fatty triangle between deltoid and pectoralis major. Variable anatomy - may bifurcate (15%), absent (2%), large tributaries (30%). Retract vein laterally with deltoid (85% of cases) or medially with pectoralis (15%) based on size and tributaries. EXAM KEY: Vein injury causes hematoma and increases infection risk. If injured, ligate properly with sutures - do not rely on diathermy alone which often fails postoperatively causing bleeding.

Exam Pearl

Technical Tip: EXAM KEY: Some surgeons sacrifice vein routinely to improve exposure (reduces retraction time, simplifies approach), but preservation preferred when possible without compromising exposure. If sacrificed, ligate proximally and distally with 2-0 or 3-0 absorbable suture to prevent bleeding and air embolism.

Dangers at this step

Cephalic vein avulsion or laceration causing hematoma
Inadequate hemostasis leading to postoperative bleeding
Air embolism if large vein torn (rare, beach chair position)

Step 3: Develop deltopectoral interval bluntly

Develop deltopectoral interval bluntly: Separate deltoid (axillary nerve C5-C6) from pectoralis major (medial and lateral pectoral nerves C5-T1) using finger dissection or blunt instrument (Mayo scissors or curved hemostat). This is a true internervous interval requiring no muscle division - safe approach with minimal denervation risk. EXAM KEY: Stay superficial to coracoacromial ligament initially - do not dive deep too early or risk axillary nerve injury. Blunt dissection follows natural tissue plane - minimal resistance when in correct plane.

Exam Pearl

Technical Tip: EXAM KEY: If deltoid partially detaches from clavicle during retraction (common in muscular patients or tight exposure), repair it at closure with transosseous sutures to prevent superior migration of deltoid origin and poor cosmesis. Some surgeons release superior 1-2cm of deltoid from clavicle intentionally to improve exposure, then repair at closure.

Dangers at this step

Axillary nerve injury if dissection too deep or inferior (nerve 5-7mm below inferior glenoid)
Deltoid or pectoralis denervation if muscle division instead of interval development
Excessive bleeding from muscle injury if sharp dissection used

Step 4: Release pectoralis major insertion partially if needed for exposure

Release pectoralis major insertion partially if needed for exposure: Elevate lateral 2-3cm of pectoralis major from humeral insertion if exposure limited. Use electrocautery to minimize bleeding. Tag with stay suture for later identification and repair. EXAM KEY: Full pectoralis release not needed in most primary cases but essential in revision or stiff shoulders (contracture limits exposure). Repair at closure with transosseous bone tunnels if released greater than 50% - failure to repair causes cosmetic deformity and weakness.

Exam Pearl

Technical Tip: EXAM KEY: Pectoralis release improves inferior humeral exposure and allows better canal preparation and cement removal in revision. Balance exposure needs against soft tissue trauma. Assess need after deltopectoral interval developed - if adequate exposure without release, preserve insertion. Tag released tendon with heavy suture (0 or #2 Ethibond) for easy identification at closure.

Dangers at this step

Excessive bleeding from pectoralis major muscle belly
Anterior circumflex humeral vessels at inferior border require control
Loss of pectoralis tendon if not tagged (difficult repair at closure)

Step 5: Identify and protect conjoint tendon (coracobrachialis and short head biceps) medially

Identify and protect conjoint tendon (coracobrachialis and short head biceps) medially: Palpate firm strap-like structure medially - this is the conjoint tendon with musculocutaneous nerve entering at variable level (3-8cm distal to coracoid, mean 5.5cm). Retract medially with Hohmann or deep deltopectoral retractor. EXAM KEY: Never place retractor medial to conjoint - risks musculocutaneous nerve injury causing biceps weakness (flexion and supination) and lateral forearm numbness. Retractor lateral to conjoint, medial edge of retractor against conjoint, medial retraction of conjoint as unit protects nerve.

Exam Pearl

Technical Tip: EXAM KEY: In 85% of patients, musculocutaneous nerve enters conjoint 5-6cm distal to coracoid tip (range 3-8cm, outliers 2cm). Excessive medial retraction or prolonged retraction (greater than 90-120 minutes continuous) causes neuropraxia. Release retractor periodically if case prolonged to allow nerve reperfusion. Nerve injury typically recovers 3-6 months but causes significant patient distress and medicolegal concern.

Dangers at this step

Musculocutaneous nerve injury from medial retractor placement or excessive medial retraction force
Neuropraxia from prolonged retraction duration (greater than 2 hours)
Brachial plexus stretch injury if excessive medial retraction combined with arm manipulation

Step 6: Release subscapularis via lesser tuberosity osteotomy or tendon peel

Release subscapularis via lesser tuberosity osteotomy or tendon peel: SUBSCAPULARIS MANAGEMENT OPTIONS: (1) Lesser tuberosity osteotomy (PREFERRED): 5-7mm bone wafer including subscapularis insertion, oscillating saw parallel to articular surface starting at superior edge of subscapularis insertion, complete osteotomy with osteotome inferiorly, preserve bone quality for healing, tag with three #5 nonabsorbable sutures (FiberWire or Ethibond) through pre-drilled holes in bone fragment. (2) Tendon peel: release 5mm lateral to subscapularis insertion on lesser tuberosity using electrocautery or sharp dissection, tag with multiple sutures. (3) Subscapularis tenotomy: divide tendon-muscle junction 2-3cm medial to insertion - poorest healing but maximal mobilization. EXAM KEY: Lesser tuberosity osteotomy allows strongest repair (bone-to-bone healing) and best healing (less than 2% failure) - preferred technique for primary TSA. Subscapularis failure post-TSA causes anterior instability and poor outcomes.

Exam Pearl

Technical Tip: EXAM KEY: Subscapularis failure post-TSA is devastating - causes anterior instability, recurrent dislocation, pain, poor function. Secure repair essential. Know examiners may ask to justify approach choice and describe repair technique in detail. Outcomes data: LTO failure less than 2%, peel 5%, tenotomy 10-15%. LTO allows earlier mobilization (4 weeks vs 6 weeks) due to superior fixation strength.

Dangers at this step

Excessive bone removal (greater than 7mm wafer) weakens tuberosity and increases fracture risk
Axillary nerve injury during inferior release (nerve 5-7mm below glenoid)
Anterior circumflex humeral vessels at inferior subscapularis border require control
Tuberosity fracture if osteoporotic bone or aggressive osteotomy technique

Step 7: Perform 360° circumferential capsular release

Perform 360° circumferential capsular release: Release capsule from glenoid rim circumferentially: (1) Superior - release rotator interval (between subscapularis and supraspinatus), coracohumeral ligament, superior capsule from glenoid. (2) Anterior - already released with subscapularis. (3) Inferior - release inferior capsule from 3-6 o'clock position on glenoid with curved osteotome, stay on bone to avoid axillary nerve (5-7mm inferior to glenoid rim). (4) Posterior - capsulotomy with electrocautery, release adhesions, tag posterior cuff for later identification. EXAM KEY: Inadequate release prevents humeral head dislocation and glenoid visualization, making surgery unnecessarily difficult and increasing soft tissue trauma from forced retraction. Complete release allows atraumatic dislocation.

Exam Pearl

Technical Tip: EXAM KEY: Inferior release is most critical and most commonly inadequate. Use curved osteotome (not straight) staying on glenoid bone to avoid axillary nerve 5-7mm inferior to inferior glenoid rim. Palpate nerve if concerned - strap-like structure inferior and medial to inferior glenoid. Complete inferior release marked by ability to dislocate humeral head anteriorly with minimal force. If difficult, reassess inferior release before forcing.

Dangers at this step

Axillary nerve injury during inferior capsular release (most common site of nerve injury)
Suprascapular nerve injury during superior release if dissection extends too far medially (nerve 2cm medial to superior glenoid in suprascapular notch)
Humeral fracture if forced dislocation before adequate capsular release
Rotator cuff tear if aggressive superior or posterior release

Step 8: Dislocate humeral head anteriorly with external rotation and extension

Dislocate humeral head anteriorly with external rotation and extension: Apply gentle longitudinal traction with arm in neutral rotation, then external rotation 20-30° and extension 20-30°. Head should deliver anterior to glenoid with minimal force if adequate soft tissue release. If difficult: (1) Reassess and complete inferior capsule release. (2) Release posterior capsule further. (3) Place bone hook on posterior humeral neck to lever head anteriorly. EXAM KEY: Never force dislocation - risks humeral fracture (especially osteoporotic bone, previous fracture, or rheumatoid arthritis), greater tuberosity avulsion, or rotator cuff tear. If cannot dislocate with gentle manipulation, reassess soft tissue releases - inadequate release is cause.

Exam Pearl

Technical Tip: EXAM KEY: In osteoporotic bone (T-score less than -2.5) or previous proximal humerus fracture, risk of iatrogenic humeral shaft fracture during dislocation is 1-3%. Gentle technique essential - longitudinal traction first to disengage joint, then rotation and translation. Consider prophylactic humeral cerclage wire before dislocation in very poor bone quality if high concern for fracture. Assistant controls scapula to prevent levering forces on humerus.

Dangers at this step

Iatrogenic humeral shaft fracture (metaphyseal or diaphyseal) from forced dislocation
Greater tuberosity avulsion fracture from excessive external rotation force
Rotator cuff tear (supraspinatus or infraspinatus) from forced manipulation
Glenoid fracture (rare) if levering forces transmitted to glenoid

Step 9: Assess glenoid version, inclination, and bone loss using preoperative CT data

Assess glenoid version, inclination, and bone loss using preoperative CT data: Inspect glenoid for: (1) Version - measure with glenoid version guide referenced to scapular body (normal 2-7° retroversion, range -7° anteversion to +10° retroversion). (2) Bone loss - posterior erosion (Walch B2/B3) or anterior defects, measure depth and extent. (3) Inclination - superior inclination (normal 5°) predisposes inferior loosening, excessive inclination requires correction. EXAM KEY: Preoperative CT planning essential for severe deformity (Walch B2/B3, version greater than 15°, bone loss greater than 10mm). Walch B2 glenoid (greater than 10° retroversion, posterior subluxation greater than 70%) needs eccentric reaming or augmented components - standard reaming causes excessive medialization and bone loss.

Exam Pearl

Technical Tip: EXAM KEY: Glenoid component malposition is leading cause of early loosening. Version should be corrected to neutral or slight retroversion (0-10°, ideally 0-5°). Know Walch classification in detail and be able to identify on imaging: A1/A2 (concentric, minor/major central erosion), B1/B2 (posterior subluxation less than/greater than 70%, biconcave), B3 (monoconcave posterior bone loss greater than 25° retroversion), C (dysplastic, retroversion greater than 25°). Management strategy differs for each type.

Dangers at this step

Failure to recognize severe version or bone loss leading to component malposition
Excessive reaming of B2/B3 glenoids causing medialization, bone loss, and vault perforation
Under-correction of version leaving excessive retroversion (greater than 10°) causing accelerated loosening

Step 10: Prepare humeral osteotomy site by removing osteophytes and exposing anatomic neck

Prepare humeral osteotomy site by removing osteophytes and exposing anatomic neck: Remove all peripheral osteophytes circumferentially with rongeur or oscillating saw to identify true anatomic neck. Place humeral cutting guide using: (1) Bicipital groove for version reference (20-30° retroversion relative to epicondylar axis). (2) Medullary canal axis for varus/valgus alignment (130-140° to shaft axis). (3) Templated height for head size restoration and soft tissue tensioning. EXAM KEY: Osteotomy level determines head height restoration and soft tissue tensioning - critical for stability and function. Cutting too proud (high) causes overstuffing, pain, limited motion, early loosening from excessive joint reactive forces. Cutting too low causes instability, inferior subluxation, limited function.

Exam Pearl

Technical Tip: EXAM KEY: Osteotomy height is one of most critical technical factors. Use anatomic landmarks: natural anatomic neck (visible groove at articular margin after osteophyte removal), greater tuberosity superior edge (1cm superior to anatomic neck), medial calcar (intact in primary OA, may be eroded in inflammatory or post-traumatic). Templating from preoperative radiographs helps estimate appropriate cut level. Error toward slightly lower cut (easier to add head height with thicker component than remove bone after cutting too high).

Dangers at this step

Cutting too proximal (proud) causing overstuffing and accelerated component failure
Cutting too distal (low) causing instability and limited function
Damage to greater or lesser tuberosity during osteophyte removal
Canal perforation if aggressive osteophyte removal extends into metaphysis

Step 11: Perform humeral head osteotomy with oscillating saw at 130-140° to shaft axis, 20-30° retroversion

Perform humeral head osteotomy with oscillating saw at 130-140° to shaft axis, 20-30° retroversion: Execute osteotomy with oscillating saw following cutting guide. Check cut with trial components for: (1) Coverage of cut surface by head trial (want greater than 70% coverage). (2) Soft tissue tension in neutral position (moderate resistance to translation). (3) No bone-bone impingement of peripheral osteophytes. EXAM KEY: Version referenced to forearm with elbow 90° flexed - 20-30° retroversion means cutting guide oriented 20-30° posterior to forearm axis (forearm represents epicondylar axis orientation). Bicipital groove is 25-35° medial to epicondylar axis - useful intraoperative reference.

Exam Pearl

Technical Tip: EXAM KEY: Excessive retroversion (greater than 40°) causes posterior instability and dislocation. Inadequate retroversion (less than 10°) causes anterior impingement with arm at side (loss of external rotation) and limited overhead reach. Average native retroversion 20-30° (range 10-40°) - goal is restore native anatomy. Use bicipital groove (mark with methylene blue or suture) and forearm position as references. Assistant maintains arm position during cut to prevent version error.

Dangers at this step

Version error from improper cutting guide orientation or arm rotation during cutting
Humeral shaft fracture propagation if osteoporotic bone or aggressive sawing
Incomplete cut requiring reaming or additional sawing (creates irregular surface)
Greater tuberosity injury if saw extends laterally

Step 12: Prepare humeral canal with sequential reamers to depth 10-15cm

Prepare humeral canal with sequential reamers to depth 10-15cm: Insert canal finder to identify canal axis (avoid varus/valgus malalignment). Ream sequentially with increasing sizes (typically start 6mm, progress to 10-14mm) until cortical chatter (tactile and auditory feedback of cortical engagement). Stop when firm cortical engagement achieved - over-reaming risks fracture, under-reaming prevents stem seating. EXAM KEY: Use hand reamers (not power) for better tactile feedback and control in osteoporotic bone - power reamers increase fracture risk. Reaming depth 10-15cm maximum - radial nerve spirals around humerus at 14-20cm from acromion, deeper reaming risks nerve injury.

Exam Pearl

Technical Tip: EXAM KEY: Humeral canal anatomy varies significantly - some patients have narrow canals (8-10mm) requiring smaller stems, others have wide capacious canals (14-16mm). Have multiple stem sizes available. Modern press-fit stems achieve fixation through proximal metaphyseal filling (cancellous compression) not distal cortical engagement - proximal fill more important than distal fixation for stability and load transfer. Cemented stems require distal canal preparation for cement mantle.

Dangers at this step

Humeral shaft fracture from over-reaming or excessive force in osteoporotic bone
Canal perforation from varus/valgus malalignment during reaming
Radial nerve injury if reaming depth exceeds 15cm
Thermal necrosis if power reaming used excessively (less concern with hand reamers)

Step 13: Prepare glenoid: expose face, ream concentrically to remove all cartilage and subchondral bone

Prepare glenoid: expose face, ream concentrically to remove all cartilage and subchondral bone: GLENOID EXPOSURE: Place Fukuda or similar glenoid retractor behind humerus retracting posteriorly (protects axillary nerve). Anterior and posterior Hohmann retractors on glenoid rim. Assistant provides humeral traction and rotation to optimize visualization. REAMING: (1) Identify glenoid face center (intersection of AP and SI axes). (2) Start with smallest reamer perpendicular to glenoid face (not scapular body). (3) Ream concentrically progressing to larger sizes until all cartilage removed and uniform bleeding cancellous bone exposed. (4) Check version with guide - should be 0-10° retroversion maximum. EXAM KEY: Reaming corrects version but excess reaming causes bone loss and medialization (weakens fixation, increases joint reactive forces). Goal: minimal bone removal while achieving complete cartilage clearance and correct version (0-10° retroversion).

Exam Pearl

Technical Tip: EXAM KEY: Walch B2/B3 glenoids with greater than 15° retroversion: eccentric reaming (high-side reaming - anterosuperior) or augmented/stepped components. Eccentric reaming can correct up to 15° version but risks vault perforation if excessive. Never accept greater than 10° retroversion in final position - accelerated loosening. If cannot correct to less than 10° with safe reaming (vault adequate depth, no perforation risk), use augmented component or consider bone grafting. Alternative: reverse TSA if cuff questionable or severe bone loss.

Dangers at this step

Vault perforation from excessive reaming depth or eccentric reaming in thin vault (neurovascular injury)
Glenoid fracture from excessive reaming force or poor bone quality
Under-reaming leaving cartilage islands (poor cement interdigitation and fixation)
Excessive medialization from over-reaming (increases joint reactive forces and loosening risk)

Step 14: Create central peg/keel hole and peripheral peg holes with drill guides

Create central peg/keel hole and peripheral peg holes with drill guides: Use component-specific drill guides ensuring perpendicular orientation to glenoid face. PEGGED COMPONENTS: Drill central hole 20-25mm depth plus 4 peripheral holes 15-20mm depth using drill guide. KEELED COMPONENTS: Create central keel slot with saw or high-speed burr 20-25mm depth. EXAM KEY: Hole depth critical - too shallow prevents component seating (proud component, instability, accelerated wear), too deep risks vault perforation and neurovascular injury (brachial plexus and axillary vessels 2-3cm medial to glenoid). Vault depth average 25-30mm but highly variable (range 15-40mm) - check preoperative CT and use depth gauge intraoperatively before drilling.

Exam Pearl

Technical Tip: EXAM KEY: Preoperative CT shows vault depth and version in 3D - essential for surgical planning especially in dysplastic or eroded glenoids. Use depth gauge to confirm adequate bone stock before drilling each hole. If vault thin (less than 15mm remaining after reaming), consider stemless humeral component only (hemiarthroplasty) or reverse TSA. Drilling posterior holes in B2/B3 glenoids highest risk of perforation due to posterior bone loss - reduce depth or omit posterior peripheral peg if vault inadequate.

Dangers at this step

Vault perforation causing neurovascular injury (brachial plexus, axillary vessels, suprascapular vessels)
Glenoid fracture if drill binds or excessive force applied
Component malposition if drill guide not perpendicular to glenoid face
Inadequate depth causing proud component and accelerated wear

Step 15: Cement glenoid component with pressurization technique

Cement glenoid component with pressurization technique: CEMENTING TECHNIQUE: (1) Pulse lavage glenoid surface (remove debris, blood, bone particles) and dry with gauze sponges on suction (completely dry surface essential for cement interdigitation). (2) Mix cement (low viscosity bone cement preferred for better penetration) and wait until dough phase consistency (not liquid - runs out, not hard - won't pressurize). (3) Place cement in peg/keel holes using pressurizer syringe or finger pressure (fill completely, express air). (4) Apply thin layer (2-3mm) to component back surface. (5) Insert component and pressurize with impactor maintaining perpendicular orientation until fully seated and cement extrudes peripherally (confirms pressurization and complete seating). (6) Remove excess cement meticulously with curette (especially posterior - cement debris causes pain and glenoid irritation). (7) Maintain impactor pressure until cement hardens (8-10 minutes - prolonged time but essential for fixation). EXAM KEY: Radiolucent lines less than 1.5mm around glenoid are acceptable (stress shielding, normal adaptation); lines greater than 2mm indicate loosening risk or poor initial fixation.

Exam Pearl

Technical Tip: EXAM KEY: Cement pressurization improves cement interdigitation into trabecular bone and fixation strength. Unpressurized cement has significantly lower pull-out strength and higher early loosening rates. All-polyethylene pegged components have best long-term survival data (95% 10-year survival AOANJRR) superior to keeled (92% 10-year) and significantly better than metal-backed components (82% 10-year - avoid). Use standard low viscosity bone cement (Simplex, Palacos) not antibiotic-loaded cement routinely in primary surgery.

Dangers at this step

Component malposition if not fully seated or tilted during insertion
Cement extrusion posteriorly causing glenoid irritation, pain, nerve irritation
Air pockets in cement causing weak fixation points
Premature cement hardening before component fully seated (timing critical)
Thermal necrosis of bone from cement polymerization (theoretical concern, rarely clinically significant)

Step 16: Trial humeral components - check head size, offset, stability through ROM

Trial humeral components - check head size, offset, stability through ROM: Assemble trial stem plus trial head (multiple sizes available typically 38-52mm diameter). Assess: (1) Head coverage of osteotomy surface (want greater than 70% coverage - incomplete coverage causes edge loading). (2) Joint reduction tension (should be moderate - firm resistance to translation but not excessively tight, able to translate 25-50% of glenoid diameter with manual stress). (3) Stability through full ROM - no subluxation or dislocation with ROM to limits (forward elevation 150°, external rotation 40°, internal rotation to L3). (4) Impingement-free motion (no bone-bone contact, soft tissue impingement). (5) Arm length restoration (compare to contralateral, assess soft tissue tension). EXAM KEY: If unstable, consider: larger head diameter, more head offset, check soft tissue repair (subscapularis). If too tight (overstuffed): smaller head, less offset, check osteotomy level (may need to lower cut if excessive). Component selection directly affects outcomes - overstuffing is common error leading to pain, stiffness, accelerated loosening.

Exam Pearl

Technical Tip: EXAM KEY: Head size selection balances coverage (want maximum to avoid edge loading) and soft tissue tension (avoid overstuffing). Most patients use 44-50mm heads. Overstuffing defined as excessive soft tissue tension preventing easy ROM, causes pain, stiffness, early loosening from increased joint reactive forces. Clinical signs: difficult reduction requiring force, cannot achieve ROM, soft tissues blanch from tension. If overstuffed, must address - downsize head, check osteotomy level, assess glenoid position.

Dangers at this step

Inadequate reduction assessment leading to postoperative instability
Overstuffing not recognized causing pain and stiffness
Trial component disassembly or fracture during trialing
Iatrogenic fracture from excessive force during ROM testing

Step 17: Insert final humeral stem - cemented or press-fit based on bone quality and stem design

Insert final humeral stem - cemented or press-fit based on bone quality and stem design: PRESS-FIT TECHNIQUE (for modern metaphyseal-filling stems in good bone quality): Clean canal with pulse lavage, dry with gauze. Assemble final stem and head. Impact stem incrementally with mallet checking version alignment after each impact (reference bicipital groove mark and forearm position). Achieve solid seating with firm cortical contact (tactile and auditory feedback changes when fully seated). CEMENTED TECHNIQUE (for older smooth stems or poor bone quality - osteoporosis, inflammatory arthritis, revision): Brush canal, pulse lavage, dry with gauze on sucker. Insert cement restrictor 2cm past planned stem tip. Inject cement retrograde (distal to proximal) with cement gun until canal filled to osteotomy level. Insert stem with steady pressure maintaining version (assistant stabilizes arm, mark bicipital groove for reference). Hold steady pressure until cement sets (8-10 minutes). EXAM KEY: Modern trend toward press-fit metaphyseal stems - easier extraction if revision needed, avoid cement removal, good outcomes in primary surgery with adequate bone. Cement still preferred for osteoporotic bone (T-score less than -2.5) or older smooth stems requiring distal fixation.

Exam Pearl

Technical Tip: EXAM KEY: Version control critical during insertion - humeral component malposition (excessive retroversion or anteversion) causes instability. Mark bicipital groove with methylene blue or colored suture before stem insertion. Assistant holds arm in neutral rotation (elbow 90°, forearm vertical) while stem inserted and impacted. Surgeon checks bicipital groove alignment frequently - should be 25-35° medial to forearm (aiming for 20-30° retroversion relative to epicondylar axis). Common error: arm drifts into rotation during insertion causing version error.

Dangers at this step

Humeral shaft fracture from over-impaction of press-fit stem or oversized stem
Version malposition causing instability (excessive retroversion - posterior instability, inadequate retroversion - anterior impingement)
Cement extravasation if excessive cement or inadequate restrictor
Stem subsidence if inadequate press-fit fixation or poor bone quality

Step 18: Repair subscapularis with transosseous sutures through bone tunnels

Repair subscapularis with transosseous sutures through bone tunnels: LESSER TUBEROSITY OSTEOTOMY REPAIR (PREFERRED): (1) Reduce tuberosity fragment anatomically against humeral shaft at original position (avoid medializing). (2) Drill three 2mm holes in humeral shaft adjacent to tuberosity bed exiting laterally on shaft 2-3cm distal to osteotomy. (3) Pass #2 or #5 nonabsorbable sutures (Ethibond, FiberWire) through drill holes from medial to lateral. (4) Pass sutures through drill holes in bone fragment (made at time of osteotomy) and adjacent subscapularis tendon. (5) Reduce arm to 30° internal rotation (neutral too much tension, excessive IR allows laxity). (6) Tie sutures over bone bridge on lateral shaft with solid knots. Results in 6-point repair (3 sutures, 2 limbs each) providing excellent fixation strength. TENDON PEEL REPAIR: Repair tendon to bone using 3-4 suture anchors in lesser tuberosity or transosseous bone tunnels, side-to-side repair if tissue quality allows, tie with arm 30° IR. EXAM KEY: Subscapularis repair strength determines postoperative protocol. Strong repair (LTO) allows earlier motion (passive ROM week 0-4, active week 4-6) than tendon repair (passive only week 0-6, active week 6-12). Failure to protect repair adequately causes failure and instability.

Exam Pearl

Technical Tip: EXAM KEY: Subscapularis failure rate 10-15% with tendon tenotomy, 5% with tendon peel, less than 2% with lesser tuberosity osteotomy - LTO clearly superior technique. Repair failure causes anterior instability, recurrent dislocation, pain, poor function - devastating complication requiring revision surgery (often conversion to reverse TSA). Examiners expect detailed knowledge of repair techniques and healing data. Postoperative protocol must protect repair - sling 6 weeks minimum, no active IR strengthening until 12 weeks.

Dangers at this step

Tuberosity fracture from drill holes too close together or aggressive reduction
Suture pull-through if bone quality poor or sutures tied too tight
Inadequate reduction leading to malposition and altered biomechanics
Axillary nerve injury if sutures placed too inferior or retraction excessive

Step 19: Repair rotator interval if released, close deltopectoral interval

Repair rotator interval if released, close deltopectoral interval: Repair rotator interval (if released - not routine) with interrupted absorbable sutures (2-0 Vicryl) reapproximating subscapularis to supraspinatus/coracoacromial ligament. Do NOT repair deltopectoral interval - allow natural tissue planes to appose without suturing (closure causes compartment syndrome and deltoid denervation). Repair pectoralis major to humerus if released greater than 50% using transosseous sutures or bone tunnels (prevents cosmetic deformity and weakness). EXAM KEY: Closing deltopectoral interval is ERROR causing compartment syndrome (rare but devastating), deltoid denervation (more common), and wound complications. Never close this interval - cardinal rule in deltopectoral approach.

Exam Pearl

Technical Tip: EXAM KEY: Some surgeons place suction drain in subacromial space - controversial, no high-quality evidence shows benefit in reducing hematoma or infection in primary TSA. If drain used, remove at 24 hours (prolonged drainage increases infection risk). Drains may increase pain and limit early motion. Current trend away from routine drainage in primary surgery - reserve for revision, anticoagulated patients, or concerning intraoperative bleeding. Meticulous hemostasis superior to drainage.

Dangers at this step

Compartment syndrome if deltopectoral interval closed (cardinal error)
Deltoid denervation from sutures through muscle or excessive closure tension
Inadequate hemostasis leading to hematoma formation
Lost pectoralis tendon if released and not repaired (cosmetic deformity)

Step 20: Layered closure: subcutaneous with 2-0 absorbable, skin with subcuticular 3-0 monofilament

Layered closure: subcutaneous with 2-0 absorbable, skin with subcuticular 3-0 monofilament: Close subcutaneous tissue in one or two layers with 2-0 Vicryl or Monocryl running or interrupted sutures, eliminate dead space, ensure hemostasis. Avoid closing superficial fascia separately (no benefit, more pain, longer operative time). Close skin with 3-0 or 4-0 Monocryl subcuticular running stitch (better cosmesis, patient preference) or staples (faster but lower satisfaction, more painful removal). Apply sterile dressing (dry gauze and tegaderm or similar) and sling with arm in neutral rotation and slight abduction (pillow or abduction wedge not needed for anatomic TSA). EXAM KEY: Wound closure critical for infection prevention - meticulous technique, avoid dead space, ensure hemostasis, gentle tissue handling. Wound complications (drainage, dehiscence, necrosis) increase infection risk significantly - prevention essential. Consider skin glue overlay for waterproof seal in high-risk patients.

Exam Pearl

Technical Tip: EXAM KEY: Skin closure technique affects cosmesis but not infection rate in primary surgery (large registry data shows no difference staples vs subcuticular). Patient satisfaction significantly higher with subcuticular closure (less painful, better appearance, no removal needed). Use staples only if time-critical or skin quality poor (very thin, friable). Subcuticular closure adds 5 minutes but worthwhile for patient experience. Examiners may ask about evidence for closure techniques.

Dangers at this step

Wound dehiscence from excessive tension or poor tissue quality
Hematoma from inadequate hemostasis (increases infection risk)
Skin necrosis at closure points if sutures too tight or tissue devascularized
Suture abscess or reaction (rare with modern monofilament)

Post-operative Care

Immediate Post-operative (0-24 hours): Recovery room monitoring for neurovascular status (document radial pulse, motor function - deltoid, biceps, wrist/finger extension, sensory testing), pain control (interscalene block typically provides excellent analgesia 12-24 hours), radiographs (AP and axillary lateral to confirm component position, assess reduction, rule out fracture or dislocation), DVT prophylaxis (mechanical compression devices, early mobilization, consider pharmacologic if high risk but bleeding concerns with interscalene block).

Sling Immobilization: 6 weeks for tendon peel or tenotomy repair, 4 weeks if secure lesser tuberosity osteotomy repair. Sling for comfort and protection - not strict immobilization. Remove for hygiene, exercises. Sleep in sling to prevent uncontrolled movement.

Rehabilitation Protocol - Strong Repair (LTO):

Weeks 0-4: Passive ROM only (pendulums 3-5 times daily, therapist-assisted elevation and ER to tolerance, pulley exercises), no active motion, no lifting
Weeks 4-6: Active-assisted ROM (continue passive program, add active-assisted with stick or pulley, gentle AAROM elevation and rotation)
Weeks 6-12: Active ROM (progress to active elevation, rotation, functional activities), gentle strengthening with resistance bands (progress from 0.5kg to 2kg resistance)
Weeks 12-24: Progressive strengthening (advance resistance, functional activities, return to swimming/golf 4-6 months), avoid heavy overhead lifting (greater than 25 pounds repetitive)

Rehabilitation Protocol - Standard Repair (Peel/Tenotomy):

Weeks 0-6: Passive ROM only (protect repair, no active IR), pendulums and therapist-assisted only
Weeks 6-12: Active-assisted ROM (gradual progression, monitor for apprehension or instability)
Weeks 12-18: Active ROM and gentle strengthening
Weeks 18-24: Progressive strengthening to functional levels

Follow-up Schedule: 2 weeks (wound check, remove sutures/staples if used), 6 weeks (radiographs, assess healing, progress therapy), 12 weeks (radiographs, assess ROM and strength), 6 months, 1 year, then annually (monitor for loosening, component position, late complications).

Activity Restrictions: No heavy overhead lifting (greater than 25 pounds repetitive) lifelong (component longevity concern), low-impact activities encouraged (swimming, golf, cycling), high-impact activities discouraged (contact sports, heavy labor), return to driving when off narcotics and can control vehicle (typically 6-8 weeks).

Radiographic Follow-up: Baseline postoperative radiographs (AP, axillary lateral), 6 weeks (assess component position, early loosening signs), 3 months, 6 months, 1 year, then annually. Monitor for: radiolucent lines (greater than 2mm or progressive concerning for loosening), component migration or subsidence, periprosthetic osteolysis, heterotopic ossification, component wear.

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOChallenging

Scenario 1: Walch B2 Glenoid Management

EXAMINER

"A 72-year-old presents with shoulder pain and stiffness. Radiographs show glenohumeral arthritis with posterior glenoid erosion and humeral head subluxation. CT shows 18° retroversion. How do you manage this and what are the technical challenges?"

EXCEPTIONAL ANSWER

This is a Walch B2 glenoid with significant posterior erosion and excessive retroversion requiring careful preoperative planning and intraoperative management. The Walch B2 classification indicates biconcave glenoid morphology with greater than 70% posterior humeral head subluxation and typically 10-20° retroversion. At 18° retroversion, this exceeds the acceptable range (0-10°) for standard glenoid component positioning and requires correction to prevent accelerated posterior eccentric loading and loosening. Management options include: (1) Eccentric reaming (high-side anterior-superior reaming) to correct version - can typically correct up to 15° of retroversion but risks excessive bone loss, medialization, and vault perforation if aggressive. This technique involves sequential reaming progressively removing more anterior-superior bone while preserving posterior bone stock. (2) Posterior bone grafting using structural autograft from resected humeral head or distal tibia allograft to restore posterior bone stock and correct version to neutral - technically demanding but preserves glenoid bone and avoids excessive medialization. (3) Augmented or stepped glenoid components with posterior wedge to fill defect and correct version - limited long-term data but biomechanically sound, some designs are metal-backed which have higher failure rates. (4) Consider reverse TSA if rotator cuff questionable or severe bone loss makes anatomic reconstruction unfavorable - lower technical demand, more predictable outcomes but different biomechanics and activity restrictions. My preferred approach would be eccentric reaming if vault depth adequate (greater than 20mm after initial reaming) to correct to 5-10° retroversion, with intraoperative assessment and willingness to convert to augmented component or reverse TSA if correction inadequate or bone stock insufficient. Preoperative CT with 3D reconstruction is essential for surgical planning, intraoperative version measurement with guide, and acceptance that perfect correction may not be achievable - goal is less than 10° final retroversion.

VIVA SCENARIOChallenging

Scenario 2: Post-TSA Anterior Instability

EXAMINER

"Six months after anatomic TSA, a patient returns with anterior shoulder pain and recurrent subluxation episodes with overhead activities. Examination shows positive belly-press and lift-off tests. What is your differential diagnosis and management approach?"

EXCEPTIONAL ANSWER

This presentation is highly concerning for subscapularis repair failure causing anterior instability - the most common cause of recurrent instability after anatomic TSA. The positive belly-press test (inability to press belly with hand, elbow drops posteriorly) and lift-off test (inability to lift hand off back against resistance) indicate subscapularis insufficiency. Differential diagnosis includes: (1) Subscapularis repair failure (most likely) - tendon pull-through from sutures, bone fragment nonunion if LTO technique, progressive attenuation or re-rupture. Incidence 10-15% with tenotomy, 5% with peel, less than 2% with lesser tuberosity osteotomy. (2) Component malposition - excessive humeral retroversion (greater than 40°) causes posterior translation and compensatory anterior instability, inadequate glenoid retroversion correction causing eccentric loading. (3) Component undersizing - inadequate soft tissue tension from small head or low osteotomy cut. (4) Infection - must always exclude, can present with instability, pain, and mechanical symptoms. (5) Atraumatic capsular laxity (rare in this timeframe). My diagnostic workup would include: detailed examination documenting ROM (typically painful arc, limited IR strength, apprehension), radiographs (AP, axillary lateral, scapular Y) assessing component position and version, laboratory studies (ESR, CRP) to exclude infection, ultrasound or MRI to assess subscapularis integrity and retraction, CT scan with 3D reconstruction to measure component version precisely (humeral and glenoid). Management depends on findings: (1) Subscapularis failure with instability and tissue present - revision subscapularis repair or reconstruction using Achilles tendon allograft augmentation, pectoralis major transfer (less ideal biomechanics), or anterior capsular reconstruction. Success rate revision repair 60-70%, lower than primary repair. (2) Subscapularis failure with tissue deficiency or irreparable tear - conversion to reverse TSA (preferred option - RSA does not rely on subscapularis, provides excellent stability and function after failed anatomic TSA, 85-90% good outcomes). (3) Component malposition - revision of humeral or glenoid component to correct version combined with soft tissue repair/reconstruction. (4) Infection - two-stage revision protocol with explantation, antibiotic spacer, organism-specific IV antibiotics 6 weeks, reimplantation if infection cleared. Prevention is key - secure subscapularis repair with lesser tuberosity osteotomy preferred technique, appropriate version (humeral 20-30° retroversion, glenoid neutral to 10°), adequate soft tissue tensioning, protected postoperative rehabilitation respecting healing (sling 6 weeks, passive ROM only initially, no active IR strengthening until 12 weeks).

VIVA SCENARIOChallenging

Scenario 3: Subscapularis Management Technique

EXAMINER

"Describe your technique for subscapularis management in anatomic TSA. Compare the three main approaches and justify your preferred technique with evidence."

EXCEPTIONAL ANSWER

Subscapularis management is arguably the most critical technical aspect of anatomic TSA as subscapularis integrity determines anterior stability and functional outcomes. The three main approaches are lesser tuberosity osteotomy (LTO), subscapularis peel, and subscapularis tenotomy, with significant differences in healing rates, failure rates, and functional outcomes. My preferred technique is lesser tuberosity osteotomy based on superior healing and lower failure rates in the literature. LTO Technique: (1) Identify subscapularis insertion on lesser tuberosity after capsulotomy. (2) Score osteotomy line with electrocautery 5-7mm lateral to tendon insertion creating wafer 5-7mm thick. (3) Use oscillating saw parallel to articular surface to create clean osteotomy from superior to inferior, complete inferiorly with osteotome. (4) Place three drill holes in bone fragment with 2mm drill and pass #5 FiberWire or Ethibond sutures, tag fragment and retract medially. (5) Complete capsular releases and arthroplasty. (6) Repair: drill three 2mm tunnels in humeral shaft adjacent to osteotomy bed exiting laterally 2-3cm distal, pass sutures through tunnels, reduce bone fragment anatomically checking position, tie sutures with arm in 30° internal rotation creating 6-point repair. Advantages: bone-to-bone healing (stronger than tendon-to-bone), anatomic repair possible, failure rate less than 2% (Miller et al. JBJS 2011 systematic review), allows earlier mobilization due to superior fixation strength, easier to identify and repair at correct anatomic position. Disadvantages: technically more demanding, requires oscillating saw, risk of tuberosity fracture (less than 1%), risk of nonunion (less than 1%). Subscapularis Peel Technique: Release subscapularis 5mm lateral to lesser tuberosity insertion sharply or with electrocautery, tag with multiple #2 sutures, repair to bone at closure using suture anchors or bone tunnels with side-to-side repair if tissue allows. Advantages: preserves bone stock, no tuberosity fracture risk, familiar technique. Disadvantages: tendon-to-bone healing less reliable (failure 5%), difficult to achieve anatomic length, scar tissue formation limits excursion. Subscapularis Tenotomy Technique: Divide subscapularis at tendon-muscle junction 2-3cm medial to insertion, repair with side-to-side sutures. Advantages: maximal mobilization (useful in stiff or revision shoulders), fastest release. Disadvantages: poorest healing (failure 10-15%), tendon-to-tendon or tendon-to-muscle healing unreliable, highest instability risk. Evidence: Miller et al. systematic review (JBJS 2011) of 1,952 shoulders showed LTO failure rate 1.9%, peel 4.8%, tenotomy 10.2%, with subscapularis failure strongly associated with anterior instability (85%) and poor functional outcomes. Multiple subsequent studies confirm LTO superiority. Registry data (AOANJRR) shows revision for instability 3-4x higher with tenotomy versus LTO. My practice is LTO for all primary anatomic TSA unless specific contraindication (severe osteoporosis with tuberosity fracture concern, revision with inadequate bone stock). For revision or very stiff shoulders requiring maximal mobilization, I use subscapularis peel with meticulous repair technique accepting higher failure risk - would not use tenotomy except extreme circumstances. Postoperative protection adjusted based on repair: LTO allows passive ROM immediately and active motion at 4 weeks, peel and tenotomy require 6 weeks passive only then gradual active progression.