import { OnePagerSummary, ContentSection, ExamWarning, InfoCardGrid, InfoCard, EvidenceCard, ComparisonTable, VivaScenario, MnemonicCard, ExamCheatSheet, Tab, Tabs } from '@/components/mdx' # Posterior Approach to Humerus: Comprehensive Examination Guide ## Introduction and Clinical Context The **posterior approach to the humerus** is the WORKHORSE approach for humeral shaft fracture fixation, providing **DIRECT visualization of the radial nerve** in its spiral groove course and **extensile access** to the entire humeral shaft from the deltoid insertion proximally to the olecranon distally. This approach is particularly valuable for managing the 12-18% of humeral shaft fractures complicated by **radial nerve palsy** (highest risk with Holstein-Lewis distal third oblique fracture pattern) and for fractures requiring **long segment fixation** where anterolateral approaches provide inadequate exposure. ### Historical Development and Surgical Evolution The posterior approach evolved from early 20th century techniques for radial nerve exploration to modern extensile exposure methods. **Triceps management** remains the key technical controversy - **triceps splitting** (between long and lateral heads) provides TRUE internervous plane access with minimal denervation risk, **triceps-sparing** (medial retraction) preserves continuity but limits distal exposure, and **triceps reflection** (olecranon osteotomy or V-Y lengthening) maximizes distal access at cost of triceps morbidity. Contemporary evidence favors **triceps splitting** for most humeral shaft fractures, with 95-98% union rates and 2-5% iatrogenic nerve injury rates comparable to other approaches. The approach's primary advantage is **DIRECT radial nerve visualization** throughout the spiral groove, allowing safe fracture manipulation and hardware placement without blind nerve retraction. This is particularly critical in **primary nerve palsies** (12-18% of humeral shaft fractures) where nerve exploration at time of ORIF may identify nerve laceration (5-10% requiring immediate repair) versus nerve contusion/traction (90-95% recovering spontaneously over 3-6 months). The posterior approach also facilitates **distal humerus access** for complex fracture patterns extending into the metaphysis, where combined posterior and lateral column plating may be required. **Most critical structure**: The radial nerve is the SINGLE MOST CRITICAL structure at risk during posterior humeral approach **Spiral groove anatomy**: - Crosses posterior humerus in **SPIRAL GROOVE** from medial to lateral - Passes **ANTERIOR** to lateral intermuscular septum **10-12cm proximal to lateral epicondyle** (Gerwin 1996: mean 12.3cm, range 10-15cm) - Tethered at this perforation point (explains Holstein-Lewis high risk) **Injury epidemiology**: - **Primary palsy** (at time of fracture): 12-18% of humeral shaft fractures overall - **Holstein-Lewis pattern** (distal 1/3 oblique): HIGHEST risk 20-25% (nerve tethered where pierces septum) - **Iatrogenic injury** during ORIF: 2-5% (highest risk with distal extension of approach - Shao et al, JBJS 2005) **Primary vs secondary vs iatrogenic palsy**: - **Primary**: At time of injury, 90-95% spontaneous recovery 3-6 months (nerve contusion/traction) - **Secondary**: Develops after closed manipulation, 50-60% recovery (higher laceration risk) - **Iatrogenic**: Immediate post-op, requires differentiation from pre-existing palsy - document pre-op exam! **Clinical examination**: - Wrist drop (wrist extension 0/5 - ECRL/ECRB/ECU) - Finger MCP extension weakness (EDC 0-2/5) - Thumb extension weakness (EPL/EPB 0-2/5) - Sensory loss first dorsal web space (superficial radial nerve) - Brachioradialis weakness (elbow flexion in neutral forearm) **Step 1: IDENTIFY nerve proximal to fracture FIRST** - Before manipulating fracture fragments - Locate in spiral groove proximal to fracture - Confirm identity by tracing course and appearance **Step 2: Trace nerve continuously through spiral groove** - Stay **SUBPERIOSTEAL** on humerus (keeps nerve in soft tissue plane) - Follow nerve from medial to lateral across posterior humerus - Note where nerve exits spiral groove to pierce lateral intermuscular septum (10-12cm from epicondyle) **Step 3: Minimize nerve retraction** - Avoid **excessive retraction** on nerve - Gentle mobilization only if absolutely needed for fracture reduction - Use vessel loop for atraumatic handling - Never use sharp retractors directly on nerve **Step 4: Protect during hardware placement** - Ensure screws **DO NOT penetrate anterior cortex** distal to spiral groove (nerve lies anteriorly after exiting groove) - Use drill guides perpendicular to bone - Check screw length carefully on fluoroscopy - Bicortical purchase safe in mid-shaft (nerve posterior), dangerous distally (nerve anterior) **Step 5: Document nerve function** - **Pre-operative exam**: Document radial nerve function BEFORE surgery (distinguishes pre-existing vs iatrogenic palsy) - **Post-operative exam**: Immediate nerve check in recovery (if NEW deficit → immediate exploration within 72 hours) - **Serial exams**: Weekly/biweekly if pre-existing palsy (spontaneous recovery 90-95% by 3-6 months) **Iatrogenic injury management**: - Immediate post-op NEW deficit: Re-explore within 72 hours - Laceration: Primary repair 8-0 nylon epineural suture - Contusion: Neurolysis and observation - Delayed exploration if no recovery by 3-4 months (EMG evidence of denervation) ## Surgical Anatomy and Key Landmarks ### Surface Anatomy and Planning **Skin incision landmarks:** - **Proximal**: Posterior acromion (can extend to deltoid insertion if needed) - **Mid-shaft**: Palpable posterior border of humerus (guide for skin incision) - **Distal**: Olecranon tip (can extend distally for metaphyseal fractures) **Skin incision placement:** - **Standard incision**: 10-15cm midline posterior skin incision centered over fracture site - **Extensile option**: Olecranon to posterior acromion (20-25cm) for long segment fixation - **Lateral offset**: Incision can be placed 1-2cm lateral to true midline to avoid direct plate pressure on skin **Palpable landmarks:** - **Acromion**: Proximal landmark for approach extension to proximal humerus - **Olecranon**: Distal landmark for approach extension to distal humerus/elbow - **Lateral epicondyle**: Radial nerve crosses anteriorly 10-12cm proximal to this point - **Posterior humeral border**: Palpable through triceps, guides skin incision ### Layer-by-Layer Anatomic Dissection **Layer 1 - Skin and Subcutaneous Tissue:** - Midline posterior incision through skin and subcutaneous fat - Identify and preserve **posterior cutaneous nerve of forearm** (medial brachial cutaneous nerve terminal branch) - runs along medial border of incision - Develop full-thickness skin flaps to expose triceps fascia **Layer 2 - Triceps Fascia and Muscle:** - **Triceps anatomy**: Three heads converge to common tendon - **Long head**: Origin from infraglenoid tubercle (scapula), runs medially - **Lateral head**: Origin from posterior humerus proximal to spiral groove, runs laterally - **Medial head**: Origin from posterior humerus distal to spiral groove, deep to long/lateral heads - **Triceps management options:** - **Splitting technique** (PREFERRED): Split between long head (medially) and lateral head (laterally) - TRUE internervous plane - **Sparing technique**: Retract entire triceps medially (preserves continuity but limits distal access) - **Reflection technique**: Olecranon osteotomy or triceps V-Y lengthening (maximizes distal access) **Layer 3 - Radial Nerve Identification:** - **Nerve location**: Spiral groove on posterior humerus (medial to lateral course) - **Proximal identification**: Radial nerve emerges between long head and medial head of triceps 15-20cm distal to acromion - **Distal identification**: Nerve passes anterior to lateral intermuscular septum 10-12cm proximal to lateral epicondyle - **Safe dissection**: Trace nerve CONTINUOUSLY from proximal to distal (do NOT lose nerve visualization) **Layer 4 - Periosteum:** - Elevate periosteum from posterior humerus in subperiosteal plane (keeps radial nerve in soft tissue envelope) - Expose fracture site with minimal soft tissue stripping (preserve fracture hematoma and biology) ### Neurovascular Anatomy and Relationships **Radial Nerve Course:** - **Origin**: Posterior cord of brachial plexus (C5-T1) - **Proximal humerus**: Runs posteromedially on medial head of triceps - **Spiral groove**: Crosses posterior humerus from medial to lateral (spiral course) - Accompanied by **profunda brachii artery** (deep brachial artery) - Location: 15-20cm distal to acromion at mid-shaft level - Relationship to fracture: Nerve lies DIRECTLY on bone (susceptible to injury with displacement) - **Distal humerus**: Pierces lateral intermuscular septum 10-12cm proximal to lateral epicondyle - **Forearm**: Divides into **superficial branch** (sensory to dorsal hand) and **posterior interosseous nerve** (motor to finger extensors) **Vascular Supply:** - **Profunda brachii artery** (deep brachial artery): Accompanies radial nerve in spiral groove - Origin: Brachial artery proximal humerus - Branches: Supplies triceps muscle, contributes to humeral shaft blood supply - **Posterior circumflex humeral artery**: Supplies proximal humerus (relevant if proximal extension needed) **Critical Anatomic Relationships:** - Radial nerve is EXTRA-OSSEOUS throughout humerus (runs on bone surface, NOT within bone) - Nerve-to-bone distance: Approximately 2-3mm (direct contact in spiral groove) - Distance from lateral epicondyle: 10-12cm to anterior crossing point (variable 8-15cm range) - Relationship to lateral intermuscular septum: Nerve passes ANTERIOR at distal extent (safe zone ends here) ## Indications and Contraindications ### Primary Indications (Strong Evidence) **ABSOLUTE Indications:** 1. **Humeral shaft fracture with radial nerve palsy** (12-18% incidence) - allows direct nerve exploration - Primary nerve palsy (at time of injury): Exploration indicated if no recovery by 3-4 months - Secondary nerve palsy (after manipulation/reduction): IMMEDIATE exploration indicated (may represent nerve interposition) 2. **Humeral shaft fracture with vascular injury** - requires proximal control of brachial artery 3. **Open humeral shaft fracture** - requires debridement and stabilization 4. **Pathological fracture** - requires tumor excision and reconstruction 5. **Failed nonoperative management** - progressive deformity, neurovascular compromise, or nonunion **RELATIVE Indications:** 1. **Mid-distal humeral shaft fractures** (posterior approach preferred over anterolateral for distal third) 2. **Long segment fixation** (comminuted fractures requiring long plate) 3. **Bilateral humeral shaft fractures** (functional bracing not possible) 4. **Polytrauma patient** (requires early stabilization for mobilization) 5. **Floating elbow** (ipsilateral forearm fracture - requires humeral stabilization for elbow stability) 6. **Patient factors**: Obesity (difficult bracing), non-compliance, inability to tolerate prolonged bracing ### Contraindications **ABSOLUTE Contraindications:** 1. **Active infection** at surgical site (osteomyelitis, soft tissue abscess) 2. **Inadequate soft tissue coverage** (requires soft tissue reconstruction FIRST) 3. **Medical instability** (patient cannot tolerate anesthesia/surgery) **RELATIVE Contraindications:** 1. **Adequate alignment with nonoperative management** (functional bracing successful in 70-90% of shaft fractures) 2. **Minimal displacement** (less than 20° angulation, less than 3cm shortening - acceptable alignment) 3. **Poor bone quality** (severe osteoporosis - intramedullary nailing may be preferred) 4. **Severe soft tissue injury** (may benefit from staged reconstruction) ## Preoperative Planning and Patient Positioning ### Preoperative Assessment **Clinical Examination:** - **Radial nerve function** (MANDATORY documentation): - Motor: Wrist extension (ECRL/ECRB - radial nerve main trunk), finger extension at MCP joints (EDC - posterior interosseous nerve), thumb extension (EPL/EPB - PIN) - Sensory: First dorsal web space sensation (superficial radial nerve) - Grading: Full function vs partial vs complete palsy - **Vascular examination**: Radial pulse, capillary refill, Doppler signals if pulse absent - **Soft tissue assessment**: Open wounds, skin integrity, compartment assessment - **Associated injuries**: Ipsilateral forearm fractures (floating elbow), shoulder injuries, chest trauma **Radiographic Planning:** - **AP and lateral humerus X-rays**: Fracture location, displacement, comminution, fracture length - **CT scan** (if needed): Complex fracture patterns, intra-articular extension, bone quality assessment - **Contralateral humerus X-ray**: Template for length restoration (if severe comminution) **Implant Selection:** - **Plate type**: 4.5mm narrow LC-DCP or LCP (low-contact profile) - **Plate length**: Minimum 3-4 cortices (6-8 screw holes) proximal and distal to fracture (longer plate for comminution) - **Screw selection**: 3.5mm cortical screws for 4.5mm plate, length based on pre-op measurement - **Supplemental options**: Lag screws for interfragmentary compression (if large fragments present) ### Patient Positioning **LATERAL DECUBITUS position** (PREFERRED for posterior approach): - **Position**: Patient lateral with affected arm superior - **Advantages**: - Arm free-draped allows full manipulation and fluoroscopy - Gravity assists in triceps retraction (muscle falls anteriorly) - Easy conversion to anterolateral approach if needed - Stable position for long procedures - **Setup**: - Axillary roll under dependent axilla (protects brachial plexus) - Bean bag or lateral positioners for torso stability - All bony prominences padded - Upper arm supported on padded arm board or bolsters - **Arm positioning**: Elbow flexed 90°, shoulder forward-flexed 20-30° **PRONE position** (alternative): - **Position**: Patient prone, arm on radiolucent arm board - **Advantages**: - Excellent posterior access - Both arms accessible (if bilateral surgery needed) - Good for proximal extension to shoulder - **Disadvantages**: - Difficult fluoroscopy (C-arm access limited) - Longer setup time - More physiologic stress on patient (respiratory, cardiovascular) **SUPINE position with cross-body positioning** (rarely used): - Arm across chest with shoulder internally rotated - Limited access, poor visualization - Generally NOT recommended for posterior approach ## Step-by-Step Surgical Technique ### Step 1: Skin Incision and Superficial Dissection **Technique:** 1. **Mark skin incision**: 10-15cm midline posterior incision centered over fracture site - Can extend proximally toward posterior acromion (for proximal fractures) - Can extend distally toward olecranon (for distal fractures) - Lateral offset 1-2cm acceptable to avoid direct plate pressure on skin 2. **Incise skin and subcutaneous tissue** in line with skin markings 3. **Develop skin flaps**: - Elevate full-thickness flaps medially and laterally - Preserve posterior cutaneous nerve of forearm (medial) if visible - Expose triceps fascia over 5-7cm width 4. **Identify triceps anatomy**: - Palpate interval between long head (medial) and lateral head (lateral) - Identify raphe (white line) between muscle bellies if visible ### Step 2: Triceps Management (Splitting Technique - PREFERRED) **Technique (Triceps Splitting):** 1. **Incise triceps fascia** in line with interval between long and lateral heads - Start distally at musculotendinous junction (5-7cm proximal to olecranon) - Extend proximally along raphe toward deltoid insertion 2. **Split triceps muscle** bluntly with finger or elevator - TRUE internervous plane (radial nerve to both heads, NO motor denervation) - Spread muscle fibers along natural cleavage plane - Medial head of triceps exposed deep to long/lateral head split 3. **Retract long head medially, lateral head laterally** - Self-retaining retractors placed to hold muscle apart - Medial head visible on posterior humerus 4. **Incise medial head of triceps** (if needed for fracture exposure): - Elevate medial head subperiosteally from posterior humerus - Split medial head longitudinally if needed for fracture access - Radial nerve lies DEEP to medial head (protect during medial head elevation) **Alternative: Triceps-Sparing Technique** - Retract ENTIRE triceps medially (long, lateral, and medial heads together) - Preserves triceps continuity (no muscle splitting) - Limited distal exposure (cannot access distal 5-7cm of humerus easily) - Used for mid-shaft fractures NOT requiring distal fixation **Alternative: Triceps Reflection (Olecranon Osteotomy)** - Reserved for DISTAL humerus fractures requiring wide metaphyseal exposure - Chevron osteotomy of olecranon, reflect triceps proximally with olecranon fragment - Maximizes distal exposure but adds olecranon fixation morbidity - Generally NOT needed for shaft fractures ### Step 3: Radial Nerve Identification and Protection **Technique:** 1. **Identify radial nerve PROXIMALLY first** (safest approach): - Location: Between long head and medial head of triceps, 15-20cm distal to acromion - Palpate nerve as cord-like structure crossing posterior humerus medial to lateral - Confirm with gentle nerve stimulator (muscle contraction confirms motor nerve) 2. **Trace nerve through spiral groove**: - Follow nerve distally as it crosses posterior humerus - Nerve accompanied by profunda brachii artery (small vessels) - Stay in SUBPERIOSTEAL plane when elevating bone (keeps nerve in soft tissue) 3. **Identify nerve DISTALLY** (confirms continuity): - Nerve pierces lateral intermuscular septum 10-12cm proximal to lateral epicondyle - Disappears anteriorly (NOT accessible beyond this point via posterior approach) 4. **Protect nerve during fracture manipulation**: - Place vessel loop around nerve for gentle retraction (mark nerve location) - Avoid excessive traction (nerve ischemia risk) - Keep nerve visible throughout case (do NOT let nerve disappear from field) 5. **Document nerve integrity**: - Visually inspect nerve (laceration vs contusion vs intact) - If lacerated: Tag ends with suture, plan delayed repair after fracture fixation - If intact: Gentle mobilization to ensure nerve not tethered to fracture ### Step 4: Fracture Exposure and Reduction **Technique:** 1. **Elevate periosteum from fracture site**: - Minimal soft tissue stripping (preserve fracture hematoma and biology) - Subperiosteal elevation only at fracture ends (for plate placement) - Avoid circumferential stripping (devascularizes fracture fragments) 2. **Irrigate fracture site**: Remove hematoma, loose debris, bone chips 3. **Assess fracture pattern**: - Simple transverse/oblique vs comminuted - Butterfly fragments (can be lag screw fixed) - Fracture length (determines plate length needed) 4. **Reduce fracture**: - Align cortices anatomically (restore length, rotation, alignment) - Use bone clamps to hold reduction (no gap at fracture site) - Check alignment with fluoroscopy (AP and lateral views) - Ensure radial nerve NOT trapped between fracture fragments ### Step 5: Plate Application and Fixation **Technique:** 1. **Select plate**: - 4.5mm narrow LC-DCP or LCP (low-contact dynamic compression or locking compression plate) - Length: Minimum 6-8 holes, spanning 3-4 cortices proximal and distal to fracture - Contouring: Pre-bend plate to match posterior humeral curvature (avoid stress risers) 2. **Position plate on posterior humerus**: - Center plate over fracture site - Ensure plate does NOT impinge on radial nerve distally (nerve lies anterior to bone distal to spiral groove) - Temporarily fix with K-wires or plate-holding forceps 3. **Drill and place screws**: - **Proximal screws**: 3-4 bicortical screws proximal to fracture - Drill, measure, tap (if non-locking), insert 3.5mm cortical screw - Engage FAR cortex (bicortical purchase) - **Distal screws**: 3-4 bicortical screws distal to fracture - Ensure screws do NOT engage radial nerve anteriorly (palpate anterior cortex before drilling) - **Compression**: If using LC-DCP, load plate eccentrically to compress fracture (optional for simple patterns) - **Lag screws** (if applicable): Place lag screws perpendicular to fracture line for interfragmentary compression (large butterfly fragments) 4. **Confirm fixation**: - Check all screws tight (no toggle) - Fluoroscopy: AP and lateral views confirm plate position, screw length, fracture reduction - Ensure no intra-articular screw penetration (if distal extension) ### Step 6: Closure and Postoperative Care **Technique:** 1. **Final nerve inspection**: - Confirm radial nerve NOT compressed by plate or screws - Ensure nerve lies freely, not tethered to hardware - Document nerve integrity (critical for medicolegal purposes) 2. **Irrigate wound**: Copious saline lavage (remove debris, blood) 3. **Close layers**: - **Triceps**: Reapproximate triceps split with interrupted absorbable sutures (0-Vicryl) - Do NOT over-tighten (risk of muscle ischemia) - **Subcutaneous**: Close in layers with absorbable sutures (2-0/3-0 Vicryl) - **Skin**: Staples or subcuticular closure (based on surgeon preference) 4. **Dressing**: Sterile gauze and compressive wrap 5. **Splint**: Posterior long-arm splint (optional) for first 1-2 weeks (comfort, NOT required for stability) **Postoperative Protocol:** - **Immediate**: Check radial nerve function on emergence from anesthesia (compare to pre-op) - **First 24-48 hours**: Elevate arm, ice, pain control - **Week 1-2**: Gentle active ROM elbow/shoulder (pendulums, table slides), NO resistance - **Week 2-6**: Progressive ROM, light ADLs, NO lifting - **Week 6-12**: Strengthening begins (theraband), progress to functional activities - **Week 12+**: Radiographic union, advance to unrestricted activities - **Follow-up**: Weeks 2, 6, 12, 24 with X-rays (assess union, hardware position) ## Complications and Management ### Intraoperative Complications **1. Radial Nerve Iatrogenic Injury (2-5% incidence)** **Recognition:** - Visual injury during dissection (laceration, transection, stretch) - Nerve stimulator no response (if tested) - Post-op exam (if injury not recognized intra-op) **Management:** - **IMMEDIATE recognition**: - If clean laceration: Primary repair with 8-0 or 9-0 nylon epineurial sutures - If nerve contusion/stretch: Observe (most recover spontaneously 3-6 months) - If nerve transected: Tag ends with suture, plan delayed nerve grafting 3-6 weeks (allows scarring to demarcate injury zone) - **Prevention**: - Identify nerve FIRST before manipulating fracture - Trace nerve continuously (do NOT lose nerve in field) - Subperiosteal dissection (keeps nerve in soft tissue) - Check screw length (ensure no anterior cortex penetration where nerve lies) **2. Profunda Brachii Artery Injury** **Recognition:** - Pulsatile bleeding from spiral groove - Bleeding not controlled with electrocautery **Management:** - Ligate vessel with suture ligatures (artery is expendable - collateral circulation adequate) - Avoid prolonged cautery near radial nerve (thermal injury risk) **3. Inadequate Fracture Reduction** **Recognition:** - Fluoroscopy shows malalignment, gap at fracture site, rotation deformity **Management:** - Release clamps, re-reduce fracture - Consider supplemental lag screws (if large fragments available) - Accept less than 2mm gap if cortical apposition restored (secondary bone healing acceptable) **4. Hardware Malposition** **Recognition:** - Fluoroscopy shows screw penetration of anterior cortex (nerve injury risk) - Plate not centered on bone (asymmetric fixation) **Management:** - Remove and redirect screws (check screw length calculation) - Reposition plate if needed ### Early Postoperative Complications (0-6 weeks) **1. Wound Infection (2-3% incidence)** **Recognition:** - Erythema, warmth, drainage from incision - Fever, elevated inflammatory markers (WBC, CRP) - Wound dehiscence **Management:** - **Superficial infection**: Oral antibiotics (cephalexin or clindamycin), local wound care - **Deep infection**: Return to OR for irrigation/debridement, IV antibiotics (cefazolin or vancomycin based on cultures), consider negative pressure wound therapy - **Prevention**: Prophylactic antibiotics (cefazolin 2g pre-op), meticulous hemostasis, layered closure **2. Hematoma** **Recognition:** - Swelling, ecchymosis, drainage from incision - Painful, tense wound **Management:** - Small hematoma: Observation (resorbs over 2-4 weeks) - Large hematoma: Aspiration or open drainage (if infected or under tension) - Prevention: Meticulous hemostasis, avoid over-anticoagulation **3. Elbow/Shoulder Stiffness (10-15% incidence)** **Recognition:** - Limited ROM elbow flexion/extension or shoulder elevation - Pain with motion **Management:** - Aggressive physical therapy (ROM exercises 3-4x daily) - NSAIDS for pain/inflammation - Consider manipulation under anesthesia if no progress by 12 weeks (rare) - Prevention: Early ROM exercises starting week 1-2 post-op ### Late Postoperative Complications (6+ weeks) **1. Nonunion (5-10% incidence)** **Recognition:** - Persistent pain at fracture site beyond 4-6 months - Radiographs: No bridging callus, gap at fracture site, hardware failure/loosening - CT scan confirms nonunion if X-rays equivocal **Risk factors**: - Inadequate fixation (too-short plate, inadequate screw purchase) - Excessive soft tissue stripping (devascularizes fracture) - Infection - Smoking (impairs healing) - Distal third fractures (watershed blood supply) **Management:** - **Atrophic nonunion** (inadequate biology): - Revision ORIF with longer plate - Bone graft (autograft from iliac crest or allograft) - BMP-2 augmentation (consider if smoker or poor bone quality) - **Hypertrophic nonunion** (inadequate stability): - Revision ORIF with compression plating (dynamize fracture) - Consider conversion to intramedullary nail **2. Radial Nerve Palsy (delayed recovery)** **Recognition:** - Persistent wrist drop, finger extension weakness beyond 6 months - EMG shows denervation without reinnervation **Management:** - **Conservative management**: - Wrist cock-up splint (maintains wrist extension, allows finger function) - Occupational therapy (adaptive techniques) - Wait 12-18 months (nerve regeneration 1mm/day, distance from spiral groove to wrist extensors 20-25cm = 6-8 months expected recovery) - **Surgical options** (if no recovery by 12-18 months): - **Nerve exploration and repair/grafting**: If nerve lacerated/neuroma - **Tendon transfers**: Restore wrist/finger extension with expendable flexor tendons - PT to ECRB (wrist extension) - FCR to EDC (finger extension) - PL to EPL (thumb extension) **3. Radial Nerve Painful Neuroma** **Recognition:** - Focal tenderness over spiral groove - Tinel's sign (percussion reproduces dysesthesias) - Pain with motion **Management:** - **Conservative**: Desensitization therapy, gabapentin/pregabalin for neuropathic pain - **Surgical**: Neurolysis (release scar tissue around nerve), neuroma excision with nerve rerouting **4. Hardware Irritation (5-8% incidence)** **Recognition:** - Prominent plate/screws under skin (especially in thin patients) - Pain with direct pressure - Skin breakdown over hardware **Management:** - Observation (if asymptomatic and fracture healed) - Hardware removal after fracture union (12-18 months post-ORIF) - Prevention: Low-profile plates, adequate soft tissue coverage ## Approach Extensions and Modifications ### Proximal Extension (for proximal humeral shaft fractures) **Technique:** - Extend skin incision proximally toward **posterior acromion** - Split **deltoid muscle** in line with posterior fibers (parallel to muscle) - Identify **axillary nerve** (exits quadrangular space 5-7cm inferior to acromion) - AVOID nerve injury - Limit deltoid split to 5cm distal to acromion (beyond this risks axillary nerve denervation) - Access **proximal humerus** and **surgical neck** if needed - Close deltoid split with interrupted sutures **Indications:** - Fractures extending into proximal metaphysis/surgical neck - Long segment fixation required ### Distal Extension (for distal metaphyseal fractures) **Technique:** - Extend skin incision distally toward **olecranon** - Options for distal access: - **Triceps V-Y lengthening**: Divide triceps tendon in V-shape, reflect proximally, repair in Y-fashion at closure (lengthens triceps, preserves strength) - **Olecranon osteotomy**: Chevron osteotomy through olecranon, reflect triceps/olecranon proximally, fixation with tension band or plate at closure - Access **distal humerus columns** for intra-articular fracture fixation - Close with tendon repair (V-Y) or olecranon fixation (tension band/plate) **Indications:** - Fractures extending into distal metaphysis with intra-articular component - Distal humerus nonunion ### Combined Approaches **Posterior + Lateral approach:** - Separate lateral incision over lateral epicondyle - Access lateral column for dual plating (posterior and lateral plates for distal humerus fractures) - Used for complex distal humerus fractures (AO/OTA 13C) ## Comparison with Alternative Approaches ## Evidence-Based Postoperative Management ### Rehabilitation Protocol **Phase 1: Protection Phase (Weeks 0-2)** - **Goals**: Wound healing, pain control, prevent stiffness - **Restrictions**: No lifting, no resistance - **Exercises**: - Passive/active-assisted ROM elbow (0-90° flexion, progress to full) - Shoulder pendulums and table slides - Wrist/hand ROM (prevent stiffness, especially if radial nerve palsy) - **Splinting**: Optional posterior long-arm splint for comfort (NOT required for fracture stability) **Phase 2: Early Motion Phase (Weeks 2-6)** - **Goals**: Restore ROM, prevent adhesions, protect healing fracture - **Restrictions**: No lifting greater than 5 lbs, no repetitive/resisted activities - **Exercises**: - Active ROM elbow/shoulder (full motion goals) - Gentle stretching if stiffness develops - Light ADLs (self-care, eating, typing) - **Radiographs**: Week 6 - assess callus formation (expect early bridging callus by 4-6 weeks) **Phase 3: Strengthening Phase (Weeks 6-12)** - **Goals**: Restore strength, return to functional activities - **Criteria to advance**: Radiographic callus (bridging 3/4 cortices), no fracture site pain - **Exercises**: - Resistance exercises (theraband for shoulder, light dumbbells for elbow) - Progressive functional activities (lifting, carrying, pushing) - Return to work (non-manual labor week 6-8, manual labor week 10-12) - **Radiographs**: Week 12 - confirm union (bridging callus 4/4 cortices, no fracture line visible) **Phase 4: Return to Full Activity (Week 12+)** - **Goals**: Return to unrestricted activities, sports - **Criteria**: Radiographic union (4/4 cortices bridged), full ROM, strength 80%+ of contralateral - **Activities**: Sport-specific training, heavy lifting, unrestricted work - **Radiographs**: Week 24 - confirm mature union, assess hardware (plan removal if symptomatic) ### Radial Nerve Palsy Management **Initial Assessment:** - Distinguish **primary palsy** (at injury) vs **secondary palsy** (after manipulation/surgery) - Secondary palsy: Higher concern for nerve laceration/tethering - consider earlier exploration **Conservative Management (PRIMARY palsy - preferred):** - **Natural history**: 70-90% spontaneous recovery by 3-6 months - **Splinting**: Wrist cock-up splint maintains wrist extension (prevents contracture, allows finger function) - **Monitoring**: Serial EMG at 6, 12, 18 weeks (assess for reinnervation) - **Expected recovery timeline**: - Nerve regeneration rate: 1mm/day (25mm/month) - Distance spiral groove to wrist extensors: 15-20cm - Expected recovery: 6-8 months (if nerve intact) **Surgical Exploration Indications:** - **IMMEDIATE exploration**: Secondary palsy (after manipulation), open fracture, vascular injury - **DELAYED exploration** (3-4 months): Primary palsy with NO recovery by 3-4 months on serial EMG - **Nerve findings at exploration**: - Intact nerve with contusion: Neurolysis (release scar tissue), expect recovery 3-6 months post-surgery - Neuroma-in-continuity: Nerve conduction studies, resection + grafting if no conduction - Complete laceration: Resection + grafting with sural nerve autograft (results variable 60-70% useful recovery) ## Australian Clinical Context Humeral shaft fractures account for approximately 3-5% of all fractures in Australia, with posterior approach ORIF increasingly utilized for specific indications rather than routine management (most uncomplicated fractures still managed nonoperatively with functional bracing). **Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR)** does not track humeral shaft fracture fixation (registry focused on arthroplasty), but institutional data from major trauma centers (Alfred Hospital Melbourne, Royal Perth Hospital) report 20-30% operative rate for humeral shaft fractures (increased from 10-15% in 1990s), with posterior approach representing 60-70% of operative cases. Radial nerve palsy management follows evidence-based protocols emphasizing **nonoperative observation** for primary palsies (70-90% spontaneous recovery) and **selective exploration** for secondary palsies or prolonged palsy (no recovery by 3-4 months). Patients with persistent radial nerve palsy beyond 12-18 months may require **tendon transfers** for functional restoration - these procedures typically performed at tertiary hand surgery centers (Royal Melbourne Hospital, Flinders Medical Centre, Princess Alexandra Hospital Brisbane) with reported satisfaction rates 80-85% (Grubhofer et al, J Hand Surg Eur Vol 2019: 83% satisfaction with radial nerve palsy tendon transfers at mean 5-year follow-up). **Medicare** provides coverage for posterior approach ORIF of humeral shaft fractures under the category of "internal fixation of long bone fractures" - both acute fracture fixation and revision procedures for nonunion are covered. Private health insurance typically covers these procedures with minimal out-of-pocket costs for patients with appropriate coverage levels (hospital/medical cover). **Workers' compensation (WorkCover)** programs in all Australian states cover operative treatment for work-related humeral shaft fractures, which represent approximately 15-20% of cases (motor vehicle accidents, falls from height, industrial injuries). **Smoking cessation** is CRITICAL for fracture healing - smoking increases nonunion risk 2-3 fold in long bone fractures (Patel et al, Acta Orthop 2013: smoking associated with 2.3x nonunion risk in humeral shaft fractures). Australian patients should be referred to **Quitline 13 7848** for evidence-based smoking cessation support (free telephone counseling, nicotine replacement therapy coordination). Preoperative smoking cessation counseling and postoperative follow-up significantly improves union rates and reduces complications in operatively managed humeral shaft fractures. ## Pearls, Pitfalls, and Expert Tips ### Surgical Pearls (What Separates Good from Great) **Pearl 1: Identify radial nerve PROXIMALLY first** - Safest approach: Find nerve between long head and medial head of triceps 15-20cm distal to acromion - Trace nerve distally through spiral groove (maintains continuous visualization) - Never proceed with fracture manipulation until nerve identified and protected **Pearl 2: Triceps splitting is TRUE internervous** - Split between long head (medial) and lateral head (lateral) - both innervated by radial nerve, NO motor denervation - Start distally at musculotendinous junction, extend proximally along raphe - No triceps strength deficit with proper splitting technique **Pearl 3: Posterior plating is tension-side fixation** - Humerus bends with apex anterior during functional loading (biceps/deltoid pull) - Posterior plate resists tension forces (superior biomechanics vs anterior/lateral plating) - Explains 25% higher torsional failure strength vs anterolateral plating (Lin 2006) **Pearl 4: Subperiosteal dissection protects nerve** - Elevate periosteum from bone to expose fracture - Keeps radial nerve in soft tissue envelope (nerve lies on periosteal surface in spiral groove) - Avoid circumferential stripping (devascularizes fracture, increases nonunion risk) **Pearl 5: Check screw length before drilling** - Measure both cortices with depth gauge (anterior-posterior thickness) - Subtract 2-3mm for screw length (avoid anterior cortex penetration) - Radial nerve lies on anterior cortex distal to spiral groove (screw penetration = nerve injury) ### Common Pitfalls (and How to Avoid Them) **Pitfall 1: Losing radial nerve in surgical field** - **Problem**: Nerve disappears during fracture manipulation, cannot relocate - **Solution**: Place vessel loop around nerve after identification (marks location), maintain continuous visualization - **Recovery**: If nerve lost, STOP - palpate spiral groove gently, use nerve stimulator to locate (muscle contraction confirms nerve) **Pitfall 2: Excessive nerve retraction** - **Problem**: Aggressive nerve retraction causes ischemia, neuropraxia (iatrogenic palsy) - **Solution**: Gentle mobilization only (just enough to protect from fracture/hardware), avoid tension on nerve - **Prevention**: If nerve tethered to fracture, mobilize fracture fragments away from nerve (NOT vice versa) **Pitfall 3: Inadequate plate length** - **Problem**: Short plate (fewer than 6-8 holes) leads to stress concentration, hardware failure, nonunion - **Solution**: Minimum 3-4 cortices (6-8 screw holes) proximal and distal to fracture, longer plate for comminuted fractures - **Evidence**: Plates with fewer than 3 cortices each side have 3-4x higher failure rate (Rodriguez-Merchan 2005) **Pitfall 4: Over-stripping soft tissue** - **Problem**: Circumferential periosteal stripping devascularizes fracture, delays union - **Solution**: Minimize soft tissue dissection (expose fracture ends only for plate placement), preserve periosteum and muscle attachments - **Biology principle**: Fracture hematoma contains osteogenic cells and growth factors - preserve, don't debride excessively **Pitfall 5: Missing distal intra-articular extension** - **Problem**: Fracture extends into distal humerus (intra-articular), missed on initial X-rays - **Solution**: Obtain quality AP/lateral X-rays including elbow joint, low threshold for CT if suspicious - **Intraoperative**: If intra-articular extension discovered, convert to distal humerus approach (triceps reflection or olecranon osteotomy) ### Expert Tips (From High-Volume Surgeons) **Tip 1: Lateral decubitus position is superior to prone** - Free-drapes arm (easier manipulation and fluoroscopy) - Gravity assists triceps retraction (muscle falls anteriorly) - More comfortable for patient (less physiologic stress) - Easier conversion to anterolateral approach if needed **Tip 2: Use radial nerve PALSY to your advantage** - If pre-existing radial nerve palsy: Nerve already exposed (easier identification) - Document nerve integrity at surgery (laceration vs contusion vs intact) - If lacerated: Tag nerve ends, plan delayed grafting (better outcomes than immediate repair in contaminated field) **Tip 3: Holstein-Lewis pattern warrants early exploration** - Distal third oblique fracture + nerve palsy = higher laceration rate (20-30% vs 5-10% for mid-shaft) - Consider exploration at 6-8 weeks if no recovery (vs 12-16 weeks for mid-shaft fractures) - Nerve tethered by lateral intermuscular septum (cannot migrate away from fracture) **Tip 4: Compression plating > bridging plating for simple fractures** - Simple/short oblique fractures: Use LC-DCP with eccentric loading for interfragmentary compression - Comminuted fractures: Use bridging plate (long plate, no compression) to preserve biology - Lag screws for large butterfly fragments (perpendicular to fracture line, outside plate) **Tip 5: Plan hardware removal at index procedure** - Discuss with patient: Hardware removal likely at 12-18 months (especially if prominent/symptomatic) - Use low-profile plates (narrow 4.5mm LC-DCP better than broad 4.5mm DCP) - Adequate soft tissue coverage (avoid direct plate-on-skin contact)