Lateral Approach to Proximal Humerus

Why Choose the Lateral Approach?

The lateral approach represents a minimally invasive alternative to the deltopectoral approach for selected proximal humerus pathology. Its key advantage is preserving the deltopectoral interval while providing excellent direct access to the greater tuberosity and rotator cuff - the two most common surgical targets in shoulder surgery.

Three Clinical Scenarios Where Lateral Approach Excels:

1. Isolated Greater Tuberosity Fractures (15-20% of proximal humerus fractures):

   • Displaced >5mm (indication for ORIF - prevents impingement)
   • Lateral approach provides DIRECT access to fracture (vs oblique deltopectoral view)
   • Fixation with screws or heavy suture easier from lateral (perpendicular to fracture plane)

2. Mini-Open Rotator Cuff Repair:

   • Small deltoid split (3-4cm) accesses supraspinatus/infraspinatus
   • Less morbidity than open deltopectoral (faster deltoid healing, less stiffness)
   • Combined with arthroscopy (arthroscopic evaluation + mini-open repair)

3. 2-Part Surgical Neck Fractures:

   • Simple fracture pattern (head-shaft only, tuberosities intact)
   • Lateral approach allows intramedullary nail insertion OR plate fixation
   • Faster than deltopectoral (less dissection, quicker closure)

Historical Context:

• 1970s-1980s: Lateral approach for rotator cuff repair standard (Neer open technique)
• 1990s: Arthroscopic cuff repair emerged - lateral approach fell out of favor
• 2000s: "Mini-open" concept revived lateral approach (combined arthroscopy + small lateral split for repair)
• 2010s-Present: Lateral / anterolateral acromial approach for fractures (locking plate via lateral window) gained traction after Gardner described the anterolateral acromial approach (J Orthop Trauma 2008); the deltopectoral approach remains the most widely used worldwide, particularly for complex patterns and arthroplasty

Global Practice Pattern: The deltopectoral approach remains the default for most proximal humerus surgery worldwide; the lateral (deltoid-splitting / anterolateral acromial) approach is selected for lateral-zone pathology - isolated greater tuberosity fractures, selected 2-part surgical neck fractures amenable to lateral plating or nailing, and mini-open cuff work. For rotator cuff repair, all-arthroscopic technique now dominates internationally, with the mini-open lateral approach reserved for massive or revision tears and surgeons earlier on the arthroscopic learning curve.

Fracture Indications

Greater Tuberosity Fractures (Primary Indication):

• Isolated GT fracture: Displaced >5mm (causes subacromial impingement - ORIF indicated)
• GT fragment in 2-part fracture: GT + surgical neck (fix both via lateral approach)
• GT malunion/non-union: Revision ORIF or excision (if small, chronic, non-salvageable)

Proximal Humerus Fractures (Selected Patterns):

• 2-part surgical neck fractures: Head-shaft fracture, tuberosities intact (intramedullary nail OR lateral plate)
• Valgus-impacted fractures: Head tilted into valgus, minimal displacement (percutaneous screw fixation via lateral)

Contraindications for Fractures:

• 3-part fractures: Inadequate exposure (need deltopectoral - access to subscapularis, anterior capsule)
• 4-part fractures: Inadequate exposure + high AVN risk (typically arthroplasty via deltopectoral)
• Fracture-dislocations: Require capsular exposure (deltopectoral mandatory)

Non-Fracture Indications

Rotator Cuff Pathology:

• Mini-open rotator cuff repair: Small-medium tears (arthroscopic visualization + mini-open repair)
• Massive rotator cuff tears: Open repair via lateral (5-7cm split - access supraspinatus, infraspinatus, superior capsule)
• Rotator cuff revision: Failed arthroscopic repair (open repair via lateral for better visualization)

Subacromial Pathology:

• Subacromial decompression: Acromioplasty (remove anterior-inferior acromion - treat impingement)
• Calcific tendinitis: Excision of calcific deposit (supraspinatus tendon - lateral approach direct access)
• Os acromiale: Symptomatic unfused acromion (excision or ORIF of os acromiale fragment)

Proximal Humerus Pathology:

• Proximal humerus non-union: Surgical neck non-union after conservative treatment (ORIF with bone graft)
• Greater tuberosity malunion: Painful impingement from superiorly displaced GT (osteotomy, reduction, fixation)

Clinical Assessment

History:

• Mechanism: FOOSH (greater tuberosity fracture), direct blow to shoulder (surgical neck), chronic pain (rotator cuff)
• Functional Limitation: Cannot abduct arm (massive cuff tear), painful arc 60-120° (impingement), night pain (cuff tear)
• Prior Treatment: Failed PT, injections (rotator cuff), failed closed treatment (fracture malunion)

Physical Examination:

Inspection:

• Swelling: Shoulder contour (fracture - acute swelling, cuff tear - atrophy supraspinatus fossa)
• Ecchymosis: Anterior shoulder (fracture), lateral arm (axillary nerve injury - associated finding)
• Muscle atrophy: Supraspinatus/infraspinatus atrophy (chronic massive cuff tear - Tangent sign positive)

Palpation:

• Greater tuberosity: Tender if fractured (0.5cm lateral to bicipital groove)
• Subacromial space: Painful with palpation (impingement, cuff tear)
• AC joint: Tenderness (associated AC arthritis - may need distal clavicle excision)

Range of Motion:

• Active vs Passive: Massive cuff tear (passive > active - pseudoparalysis), stiffness (frozen shoulder - both limited)
• Painful arc: 60-120° abduction pain (subacromial impingement)
• External rotation lag: Cannot maintain ER (infraspinatus tear)

Strength Testing:

• Supraspinatus (empty can test): Arm 90° abduction, 30° forward flexion, thumbs down (resisted abduction)
• Infraspinatus (ER lag sign): Arm at side, elbow 90° flexed, maximal ER - release (if drops = infraspinatus tear)
• Subscapularis (lift-off, belly press): Assess subscapularis integrity

Neurovascular Examination (MANDATORY):

• Axillary nerve: Deltoid contraction (resisted abduction), sensation lateral arm (must document preop - axillary nerve injury in 5-10% proximal humerus fractures)
• Radial, median, ulnar nerves: Full neurological exam (brachial plexus injury rare but catastrophic)
• Vascular: Radial pulse (axillary artery injury rare <1% but requires emergent vascular repair)

Imaging Essentials

Radiographs (Trauma Series - AP, Scapular Y, Axillary):

• AP Shoulder: Greater tuberosity displacement (>5mm = surgical indication), surgical neck fracture angulation
• Scapular Y: Head position relative to glenoid (anterior/posterior dislocation), fracture pattern
• Axillary Lateral: MANDATORY (assess glenoid, posterior humeral head, greater tuberosity position)

CT Scan (Fractures):

• 3D Reconstruction: Fracture pattern (2-part vs 3-part vs 4-part), fragment size, comminution
• Greater Tuberosity Assessment: Fragment size, displacement, rotation (determines fixation strategy)
• Head-Shaft Angle: Valgus impaction (>45° valgus may be stable - percutaneous fixation)

MRI (Rotator Cuff):

• Cuff Tear Size: Small <1cm, medium 1-3cm, large 3-5cm, massive >5cm (determines repair feasibility)
• Muscle Quality: Fatty infiltration (Goutallier grade 0-4 - grade 3-4 = poor repair healing)
• Retraction: Tear retracted medially (Patte classification - stage 3 = medial to glenoid, irreparable)

Surgical Planning

Fracture Fixation Strategy:

Essential Instrumentation

Standard Set:

• Scalpel (15 blade)
• Self-retaining retractor (Kolbel shoulder retractor OR Fukuda ring retractor)
• Army-Navy retractors
• Hohmann retractors (blunt - retract deltoid, lever humeral head)
• Electrocautery (cutting and coagulation)

Shoulder-Specific:

• Deltoid Retractors: Self-retaining deltoid split retractor (maintains split without assistant)
• Humeral Head Retractors: Fukuda retractor, Darrach retractor (elevate humeral head for GT exposure)
• Suture Passers: For rotator cuff repair (if mini-open cuff repair)

Fracture Fixation:

• Cannulated Screw System: 4.0mm partially threaded screws (GT fracture fixation)
  • Guidewires (2.0mm), cannulated drill (3.2mm), depth gauge
• Lateral Proximal Humerus Plate (PHILOS): If surgical neck fracture
  • Locking screws (3.5mm), drill guides, screwdriver
• Heavy Suture: #2 Ethibond or #5 FiberWire (tuberosity-to-tuberosity, tuberosity-to-shaft sutures)

Rotator Cuff Repair (If Applicable):

• Suture anchors (5.5mm for bone - load at GT insertion)
• Suture passers (penetrating graspers, shuttles)
• Arthroscopic instruments (if combined arthroscopy + mini-open)

Implant Selection

Greater Tuberosity Fracture:

• Screws: 4.0mm cannulated partially threaded (2-3 screws, 30-50mm length typical)
• Heavy Suture: Alternative to screws (figure-8 suture GT to shaft - less rigid but lower profile)

Surgical Neck Fracture:

• PHILOS Plate: Proximal humerus locking plate (lateral position - 3-4 proximal locking screws, 3-4 shaft screws)
• Intramedullary Nail: Humeral nail (8-9mm diameter, proximal interlocking screws)

Rotator Cuff:

• Suture Anchors: 5.5mm double-loaded (2 sutures per anchor, 2-3 anchors for small-medium tear)

Beach Chair Position (Standard)

Setup:

1. Patient: Semi-recumbent 30-40° (head of bed elevated)
2. Torso: Rotated 20-30° toward operative side (opens shoulder laterally)
3. Head: Horseshoe headrest, neck neutral
4. Arm: Free drape (allows full ROM - adduction to abduction to extension)

Advantages:

• Anatomic orientation (surgeon works from lateral - natural position)
• Easy conversion if need deltopectoral (can extend incision anteriorly)
• Assistant has good access

Hypotension Risk:

• Beach chair position reduces cerebral perfusion (maintain MAP >70mmHg)
• Consider arterial line for patients >70 years, cardiac history

Lateral Decubitus (Alternative)

Setup:

1. Patient lateral decubitus, operative side up
2. Beanbag, kidney rests (prevent rolling)
3. Arm suspended from boom (30° flexion, 30° abduction)

Advantages:

• No hypotension risk
• Gravity helps distraction (humeral head falls away from acromion)

Disadvantages:

• Disorienting for surgeon (working from unusual position)
• Longer setup time

Surface Landmarks

Palpable Structures:

1. Acromion Lateral Edge: Start point for incision (most lateral bony prominence)
2. Greater Tuberosity: 2cm distal to acromion, 0.5cm lateral to bicipital groove (palpable if arm internally rotated)
3. Deltoid Insertion: V-shaped insertion on lateral humerus (10cm distal to acromion - deltoid splits ABOVE this)

Incision Planning:

• Start: Acromion lateral edge
• Direction: Extend distally 5-7cm (parallel to deltoid fibers - oblique 30° anterior to coronal plane)
• DO NOT extend >5cm from acromion (axillary nerve zone)

Deltoid Muscle Anatomy

Deltoid Fiber Direction:

• Fibers run OBLIQUELY (30° anterior to coronal plane - from acromion lateral edge distally and slightly anteriorly)
• CRITICAL: Split deltoid PARALLEL to fibers (blunt dissection along fiber direction)
• Splitting perpendicular = transects fibers (poor healing, weakness)

Deltoid Innervation:

• Axillary nerve (C5-C6, posterior cord)
• Nerve crosses the deltoid deep surface a mean 6.3cm from the anterolateral acromion (Traver 2016: range 5.2-7.6cm)
• Safe-zone rule: keep the deltoid split within about 5cm of the acromion (a conservative margin below the closest cadaveric distance) unless the nerve is identified and protected

Deltoid Origin:

• Anterior third: Clavicle lateral third
• Middle third: Acromion lateral edge (LATERAL APPROACH USES THIS)
• Posterior third: Scapular spine

Critical Neurovascular Anatomy

Axillary Nerve (HIGHEST RISK):

• Course: Exits quadrangular space (with posterior circumflex humeral artery), wraps around surgical neck of humerus posteriorly
• Position: Anterior branch crosses the deep surface of the deltoid a mean 6.3cm distal to the anterolateral acromion (Traver et al, J Orthop Trauma 2016: range 5.2-7.6cm); upper-arm length and arm position alter the distance (Samart 2014), so it is variable
• Branches: Anterior (deltoid), posterior (deltoid + teres minor), sensory (superior lateral cutaneous nerve of arm)
• Injury Consequences: Deltoid paralysis (cannot abduct arm beyond 15° - catastrophic functional loss), sensory loss lateral arm

Anterior Circumflex Humeral Artery:

• Runs deep to deltoid (at level of surgical neck)
• May bleed if extensive dissection (control with bipolar cautery)
• Safe to ligate (collateral flow via posterior circumflex humeral artery)

Suprascapular Nerve:

• Deep to rotator cuff (innervates supraspinatus, infraspinatus)
• Safe during lateral approach (not in surgical field)

Greater Tuberosity and Rotator Cuff Anatomy

Greater Tuberosity:

• Lateral prominence of proximal humerus (0.5cm lateral to bicipital groove)
• Three facets (insertion sites):
  1. Superior facet: Supraspinatus insertion (anterosuperior GT)
  2. Middle facet: Infraspinatus insertion (posterosuperior GT)
  3. Inferior facet: Teres minor insertion (posteroinferior GT)

Rotator Cuff Insertions:

• Supraspinatus: Superior facet GT (most commonly torn - degenerative or traumatic)
• Infraspinatus: Middle facet GT (second most common tear)
• Teres minor: Inferior facet GT (rarely tears - protected position)
• Subscapularis: Lesser tuberosity (NOT accessible via lateral approach - need deltopectoral)

Long Head Biceps Tendon:

• Runs in bicipital groove (between greater and lesser tuberosities)
• Landmark: GT is 0.5cm LATERAL to LHB tendon (palpate LHB, identify GT lateral to it)

Step 1: Skin Incision and Superficial Dissection

Incision:

• Position: Start at acromion lateral edge, extend distally 5-7cm
• Direction: Parallel to deltoid fibers (oblique - 30° anterior to pure vertical)
• Length: Fracture 5-7cm, rotator cuff 3-5cm (mini-open)

Skin Dissection:

• 15 blade through skin and subcutaneous tissue
• Identify deltoid fascia (overlies muscle)

Step 2: Deltoid Split

Identify Deltoid Fibers:

• Palpate deltoid muscle through fascia (fibers run obliquely)
• Fiber Direction: From acromion lateral edge distally and slightly anteriorly (30° angle)

Split Deltoid PARALLEL to Fibers:

1. Incise deltoid fascia longitudinally (parallel to fibers)
2. Blunt Dissection: Use blunt scissors or finger dissection (spread parallel to fiber direction)
   • Split opens easily if parallel to fibers
   • Resistance if perpendicular (STOP - re-assess fiber direction)
3. Depth of Split: Through full thickness of deltoid (to humerus deep surface)
4. Length of Split: keep to about 5cm from the acromion lateral edge as a conservative safe zone (measure with ruler); palpate for and protect the axillary nerve before going further

Self-Retaining Retractor:

• Place deltoid split retractor (maintains split without assistant holding)
• Gentle retraction (avoid excessive tension on deltoid - nerve stretch risk)

Step 3: Optional - Deltoid Origin Elevation (If More Exposure Needed)

Indication:

• Need wider exposure (massive cuff tear, complex fracture)
• Cannot extend split >5cm distally (axillary nerve) - so elevate origin instead

Technique:

1. Identify deltoid origin on acromion lateral edge
2. Incise periosteum along acromion lateral edge (0.5-1cm strip)
3. Elevate deltoid muscle subperiosteally from acromion (Cobb elevator)
4. Elevate 1-2cm anterior and posterior (increases exposure width without extending split distally)

Repair at Closure:

• Re-attach deltoid to acromion (transosseous sutures or suture anchors)
• Critical for deltoid strength restoration

Step 4: Expose Subacromial Space and Greater Tuberosity

Incise Subacromial Bursa:

• Deltoid split opens into subacromial space (bursa between deltoid and rotator cuff)
• Incise bursa longitudinally (exposes rotator cuff/greater tuberosity)
• Debride inflamed bursal tissue (improves visualization)

Identify Greater Tuberosity:

• Landmark: Long head biceps tendon in bicipital groove (anterior reference)
• GT Position: 0.5cm LATERAL to bicipital groove
• Palpate GT (bony prominence - fracture may be displaced/rotated)

For Fracture:

• Identify fracture line (GT fragment separated from humeral head)
• Assess fragment size, displacement, comminution

For Rotator Cuff:

• Visualize supraspinatus tendon (anterior GT insertion)
• Assess tear size, tissue quality, retraction

Step 5: Fracture Reduction (If Greater Tuberosity Fracture)

Assess Fracture:

• Fragment size (large >2cm = screw fixation, small <1cm = suture fixation)
• Displacement (superior, posterior, rotation)
• Comminution (single fragment vs multiple - affects fixation choice)

Reduce Fragment:

1. Grasp Fragment: Kocher clamp or Weber clamp (hold GT fragment)
2. Manipulate: Reduce GT to anatomic position (flush with humeral head articular surface)
   • Reduce superior displacement (GT should NOT be proud - causes impingement)
   • Reduce posterior rotation (align facets - supraspinatus facet anterosuperior)
3. Provisional Fixation: 2.0mm K-wire from GT into humeral head (holds reduction)
4. Fluoroscopy: AP and axillary views (confirm GT reduced - no superior displacement, no articular step)

Step 6: Fixation - Greater Tuberosity Fracture

Option A: Screw Fixation (Standard)

Guidewire Placement:

1. Insert 2.0mm guidewire from GT fragment into humeral head (perpendicular to fracture line)
2. Check fluoroscopy (wire crosses fracture, good head purchase, NOT intra-articular)
3. Insert second guidewire parallel to first (10-15mm spacing)

Screw Insertion:

1. Cannulated drill 3.2mm over each guidewire
2. Measure screw length (depth gauge - typical 35-50mm)
3. Insert 4.0mm partially threaded cannulated screw
   • Thread crosses fracture line (lag compression)
   • Screw head buried (countersunk in GT - avoid impingement)
4. Tighten screws (compress fracture)

Final Fluoroscopy:

• AP: GT reduced, screws within bone, no intra-articular penetration
• Axillary: GT position anatomic, screws good trajectory

Option B: Heavy Suture Fixation (Alternative)

Indication:

• Small fragment (<1cm), osteoporotic bone (screws won't hold), comminuted

Technique:

1. Pass #5 FiberWire through GT fragment (horizontal mattress through bone)
2. Pass sutures through drill holes in humerus lateral cortex (proximal to fracture)
3. Tie sutures (reduce GT to anatomic position, compress against humerus)
4. Figure-8 pattern (distributes load)

Step 7: Alternative - Surgical Neck Fracture Fixation

If 2-Part Surgical Neck Fracture:

Option A: Lateral Plate (PHILOS)

1. Position plate on lateral humerus (just posterior to bicipital groove - avoid LHB)
2. Plate should sit 5-8mm distal to GT (proximal screws target humeral head, don't violate GT)
3. Insert proximal locking screws (3-4 screws into humeral head - subchondral purchase)
4. Insert shaft screws (3-4 screws into humeral shaft - bicortical)
5. Fluoroscopy: Plate position acceptable, screws subchondral (not intra-articular)

Option B: Intramedullary Nail

1. Entry point: Lateral to GT (avoid cuff insertion - enter just anterior to supraspinatus)
2. Ream humeral canal (8-9mm reamer)
3. Insert humeral nail (antegrade - proximal to distal)
4. Proximal interlocking screws (2-3 screws lateral to medial through nail)
5. Distal interlocking screws (2 screws perpendicular to shaft)

Step 8: Rotator Cuff Repair (If Mini-Open)

If Small-Medium Rotator Cuff Tear:

Prepare Footprint:

1. Identify supraspinatus insertion on GT (superior facet - may be bare if chronic tear)
2. Debride to bleeding bone (curette, burr - promotes healing)
3. Create bone bed (footprint 1-2cm medial-lateral, 1cm anterior-posterior)

Suture Anchor Insertion:

1. Insert 5.5mm suture anchors into GT footprint (2-3 anchors, 1cm spacing)
2. Anchors at medial edge of footprint (allows tendon to be brought to bone)
3. Each anchor has 2 sutures (double-loaded - 4 free suture limbs per anchor)

Tendon Repair:

1. Pass sutures through tendon edge (mattress sutures - 1cm bites)
2. Reduce tendon to footprint (tie sutures - compress tendon to bone)
3. Check repair (tendon should cover footprint, no gap)

Step 9: Closure

Remove Retractors:

• Release deltoid split retractor

Close Deltoid Split:

• Deltoid Muscle: 0 or 2-0 Vicryl (simple interrupted sutures, reapproximate split)
  • Suture parallel to fibers (following original fiber direction)
  • 4-6 sutures (avoid excessive tension)

If Deltoid Origin Elevated:

• Repair deltoid to acromion (transosseous sutures - drill holes in acromion, pass 2-0 Ethibond through deltoid, tie over bone)

Superficial Layers:

• Deltoid Fascia: 2-0 Vicryl (running or interrupted)
• Subcutaneous: 3-0 Vicryl
• Skin: 4-0 Monocryl subcuticular

Dressing:

• Sterile gauze, ABD pads
• Sling (for fracture) OR abduction pillow (for massive cuff repair - protect repair)

Intraoperative Complications

Axillary Nerve Injury

• Risk: The single most feared complication of the deltoid-splitting approach. Reported rates vary widely; meticulous technique can keep it very low (Gardner 2008 reported no axillary nerve deficits attributable to the anterolateral acromial approach in 52 fractures), but careless distal extension or sustained retraction raises the risk substantially
• Mechanism: Splitting/retracting past the safe zone (direct injury), or sustained forceful retraction causing traction injury (Traver 2016: mean 51% nerve strain with progressive Kolbel retraction caused microscopic myelin and axonal damage even without transection)
• Presentation: Postop deltoid paralysis (cannot abduct arm), sensory loss lateral arm
• Management:
  • If nerve transected (recognised intraoperatively): primary repair (microsurgical)
  • If nerve intact (neuropraxia): observe with serial exams and EMG/NCS at about 3 months to assess denervation and recovery potential
• Recovery: Variable - neuropraxia/traction injuries often recover over 6-12 months; transection has poor spontaneous recovery and may require nerve grafting or later tendon transfer
• Prevention: measure the split (stay within the about 5cm safe zone), identify/protect the nerve before extending exposure, use blunt retractors and avoid sustained retraction

Deltoid Detachment (5%)

• Mechanism: Excessive split (fibers torn), origin elevation inadequately repaired
• Presentation: Deltoid weakness (difficulty abducting), palpable defect
• Management: Surgical repair (re-attach deltoid to acromion or repair split)

Rotator Cuff Injury (2-5%)

• Mechanism: Inadvertent entry into cuff during deltoid split (wrong plane), nail entry damages supraspinatus (if IM nail)
• Presentation: Postop cuff tear (new-onset weakness)
• Management: Repair if recognized, revision cuff repair if postop

Postoperative Complications

Stiffness (10-15%)

• Mechanism: Adhesive capsulitis (immobilization >6 weeks), deltoid scarring
• Prevention: Early PT (PROM at 2 weeks, AAROM at 6 weeks)
• Management: Aggressive PT, manipulation under anesthesia (if refractory >6 months)

Hardware Prominence (10%)

• Mechanism: PHILOS plate prominent laterally (thin soft tissue coverage), screws proud
• Management: Hardware removal (>12 months post-fracture)

Infection (2-5%)

• Standard management (superficial - oral antibiotics, deep - debridement + hardware retention if stable)

Immediate Postop

Recovery Room:

• Neurovascular check (axillary nerve - document deltoid function, sensation)
• Pain control: Interscalene block, oral opioids
• X-ray: AP, axillary (confirm hardware position)

Immobilization:

• Fracture: Sling 6 weeks
• Rotator Cuff: Abduction pillow 6 weeks (if massive tear)

Follow-up Protocol

Week 2: Wound check, X-ray, begin pendulum exercises (gravity-assisted PROM)

Week 6: X-ray (fracture healing), progress to AAROM (pulley exercises)

Week 12: Full AROM, begin strengthening

Month 6: Unrestricted activity (fracture healed)

Return to Activity (General Guidance)

Return to Work:

• Sedentary: 6-8 weeks
• Manual/heavy labour: 3-6 months (depends on fixation stability and radiographic union)

Driving: Typically resume around 6 weeks, once out of the sling and able to demonstrate safe shoulder control and reaction (varies with jurisdiction and fixation)