Anterolateral Approach to Radius (Henry)

The Henry approach is the STANDARD anterolateral (volar) approach to the entire length of the radius from the proximal 1/3 to the distal metaphysis (Henry 1945). It is the MOST VERSATILE radius approach, providing EXTENSILE exposure for radial shaft fractures, nonunion, malunion, and forearm pathology.

Internervous Plane

The Henry approach utilizes a TRUE internervous plane that VARIES by location along the radius:

Proximal 1/3 Radius (Elbow to Proximal Shaft):

• Interval: Between brachioradialis (radial nerve) laterally and pronator teres (median nerve) medially
• Deep dissection: Requires supinator muscle splitting to expose proximal radial shaft (PIN on deep surface of supinator - AT RISK)
• PIN location: 2-5cm distal to radial head, on deep surface of supinator (Spinner 1968)

Middle 1/3 Radius (Mid-Shaft):

• Interval: Between brachioradialis (radial nerve) laterally and flexor carpi radialis (FCR) (median nerve) medially
• Critical structure: Radial artery lies BETWEEN brachioradialis and FCR in this region (PRIMARY vascular hazard - Leversedge 2008)
• Deep plane: Direct exposure of radius periosteum after mobilizing radial artery medially with FPL

Distal 1/3 Radius (Distal Shaft to Metaphysis):

• Interval: Between FCR (median nerve) medially and brachioradialis tendon laterally
• Critical nerve: Superficial radial nerve emerges from under brachioradialis 6-9cm proximal to radial styloid - MOST INJURED nerve structure (5-10% sensory dysesthesia - Ring 2004)
• Deep plane: Between pronator quadratus (covers distal radius volar surface) and radius periosteum

Critical Neurovascular Structures

1. RADIAL ARTERY (PRIMARY VASCULAR HAZARD):

• Course: Lies between brachioradialis and FCR in middle/distal radius (medial to brachioradialis throughout)
• Surgical strategy: Identify artery in PROXIMAL wound, mobilize MEDIALLY with FPL and median nerve (safer than lateral retraction)
• Injury risk: 0.5-1% iatrogenic injury during Henry approach (Leversedge 2008)
• Clinical pearl: Radial artery pulsation is the LANDMARK for identifying the internervous plane

2. SUPERFICIAL RADIAL NERVE (MOST INJURED NERVE):

• Course: Runs DEEP to brachioradialis in proximal/middle forearm, emerges 6-9cm proximal to radial styloid, crosses surgical field to dorsum of hand
• Surgical strategy: Identify nerve under distal brachioradialis, protect with MEDIAL retraction (avoid stretching or compression)
• Injury risk: 5-10% sensory dysesthesia (transient 10%, permanent 2% - Ring 2004)
• Clinical manifestation: Painful neuroma, dysesthesia over dorsal thumb/index finger web space

3. POSTERIOR INTEROSSEOUS NERVE (PIN):

• At risk ONLY in proximal 1/3 dissection: PIN lies on deep surface of supinator 2-5cm distal to radial head
• Surgical strategy: Split supinator in LINE OF ITS FIBERS with forearm in FULL SUPINATION (PIN migrates anteriorly with supination - increases safety clearance - Stern 1984)
• Injury risk: 2-5% transient PIN palsy with proximal dissection (Spinner 1968)
• Clinical manifestation: Finger/thumb extension weakness (EPL, EDC, EIP), wrist drop if radial nerve involved

4. LATERAL ANTEBRACHIAL CUTANEOUS NERVE (LABC):

• Course: Terminal branch of musculocutaneous nerve, emerges lateral to biceps tendon, crosses volar forearm
• Surgical strategy: Protect with lateral skin flap retraction (avoid electrocautery near subcutaneous tissue)
• Injury risk: 2-3% sensory dysesthesia over lateral volar forearm (usually transient)

5. MEDIAN NERVE:

• Course: Lies MEDIAL to brachial artery in antecubital fossa, passes between two heads of pronator teres, gives off AIN 4-6cm distal to lateral epicondyle
• Surgical strategy: Usually NOT visualized (lies medial to surgical field), mobilize radial artery medially to avoid medial dissection
• Injury risk: Less than 0.5% (median nerve rarely injured in standard Henry approach)

Patient Positioning

Setup:

• Supine position on operating table
• Arm abducted 90° on arm board (standard upper extremity positioning)
• Forearm supinated (palm up) for most of dissection (except proximal 1/3 where supination protects PIN)
• Tourniquet on upper arm (250-280mmHg for 90-120 minutes)
• Fluoroscopy (C-arm) available for intraoperative reduction/fixation verification

Incision Planning

Skin Incision:

• Proximal extent: 2-3cm distal to antecubital fossa (to avoid crossing elbow crease)
• Distal extent: To within 4-5cm of radial styloid (to avoid SRN injury with excessive distal dissection)
• Course: Follows the mobile wad (brachioradialis muscle belly) in proximal/middle forearm
• Distal course: Curves RADIALLY toward FCR tendon (staying lateral to FCR) to reach distal radius

Incision Landmarks:

• Proximal: Lateral to biceps tendon in antecubital fossa
• Middle: Over brachioradialis muscle belly (easily palpable with wrist extension)
• Distal: Between FCR tendon (palpable with wrist flexion) and radial styloid

Superficial Dissection

1. Subcutaneous Layer:

• Incise skin and subcutaneous tissue sharply
• Identify and protect lateral antebrachial cutaneous nerve (LABC) - runs longitudinally in subcutaneous fat lateral to incision
• Ligate small superficial veins crossing surgical field

2. Fascia Incision:

• Identify brachioradialis muscle belly (lateral landmark)
• Palpate radial artery pulsation between brachioradialis and FCR/PT (medial landmark)
• Incise deep fascia LATERAL to radial artery (between artery and brachioradialis)

Deep Dissection - Three Zones

ZONE 1: PROXIMAL 1/3 RADIUS (Elbow to Proximal Shaft)

Interval: Between brachioradialis (lateral, radial nerve) and pronator teres (medial, median nerve)

Steps:

1. Retract brachioradialis laterally - exposes underlying supinator muscle and proximal radius
2. Identify biceps tendon insertion on radial tuberosity (deep medial landmark)
3. Supinator muscle splitting:
   • CRITICAL: Place forearm in FULL SUPINATION (migrates PIN anteriorly away from surgical field - Stern 1984)
   • Identify supinator covering proximal radius (extends from lateral epicondyle to radial shaft)
   • Split supinator in LINE OF ITS FIBERS (parallel to radius) using blunt dissection
   • Avoid deep dissection on dorsal radius (PIN on deep surface of supinator)
4. Subperiosteal elevation - elevate supinator from radius periosteum using elevator (exposes proximal radial shaft)

PIN Protection:

• PIN lies 2-5cm distal to radial head on deep surface of supinator (Spinner 1968)
• Full supination increases safety clearance (PIN migrates anteriorly with supination)
• Split supinator in line of fibers (NOT perpendicular to fibers)
• Avoid dissection around radial neck (highest PIN concentration)

ZONE 2: MIDDLE 1/3 RADIUS (Mid-Shaft)

Interval: Between brachioradialis (lateral, radial nerve) and FCR (medial, median nerve)

Steps:

1. Identify radial artery - lies between brachioradialis and FCR (use pulsation as landmark)
2. Mobilize radial artery MEDIALLY:
   • Incise fascia LATERAL to artery (between BR and artery)
   • Use BLUNT dissection to mobilize artery medially with FPL muscle and median nerve
   • Control artery with vessel loops if needed
3. Retract brachioradialis laterally - exposes FPL and radius shaft
4. Identify FPL muscle - covers volar radius in middle 1/3
5. Subperiosteal elevation - elevate FPL from radius periosteum (exposes mid-shaft radius)

Radial Artery Protection:

• Medial mobilization is safer than lateral retraction (reduces tension on artery)
• Use blunt dissection (avoid sharp dissection near artery)
• Vessel loops for control (NOT aggressive retraction)

ZONE 3: DISTAL 1/3 RADIUS (Distal Shaft to Metaphysis)

Interval: Between FCR (medial, median nerve) and brachioradialis tendon (lateral, radial nerve)

Steps:

1. Identify FCR tendon - palpable with wrist flexion (medial landmark)
2. Identify brachioradialis tendon - inserts on radial styloid (lateral landmark)
3. Identify superficial radial nerve (SRN):
   • Emerges from under brachioradialis 6-9cm proximal to radial styloid
   • Crosses surgical field to dorsum of hand
   • CRITICAL: Protect with GENTLE MEDIAL retraction
4. Incise deep fascia - between FCR and brachioradialis
5. Identify pronator quadratus (PQ):
   • Covers distal radius volar surface (square muscle)
   • Extends from distal 1/4 radius to distal ulna
6. Elevate PQ from radius:
   • Incise PQ along radial (lateral) border
   • Elevate PQ MEDIALLY as flap (preserves muscle for closure)
   • Exposes distal radial metaphysis

SRN Protection:

• Identify SRN exiting from under BR tendon (6-9cm proximal to styloid)
• Gentle medial retraction (NOT lateral traction)
• Minimize retraction time (release retractors periodically)
• Avoid electrocautery near nerve

Radius Exposure and Fracture Fixation

Radius Periosteum:

• Subperiosteal elevation from fracture site using elevator
• Preserve periosteal blood supply (minimize stripping at non-fracture zones)
• Expose fracture site circumferentially (BUT avoid excessive dorsal dissection - interosseous membrane preserves vascular supply)

Fracture Reduction:

• Direct manipulation of proximal and distal fragments
• Reduction clamps for provisional fixation
• Fluoroscopy for reduction verification (AP and lateral views)

Plate Fixation:

• 3.5mm LC-DCP or LCP plate on volar radius surface (standard implant)
• Screw fixation: 6 cortices proximal and distal to fracture (AO principles - Chapman 1989)
• Plate position: Centered on volar radius (avoid ulnar placement - interosseous membrane tension)
• Compression: Dynamic compression with compression screws or lag screws through plate

Closure

Deep Layers:

1. Pronator quadratus repair (distal 1/3 dissection) - reattach PQ to radial border with interrupted sutures
2. Supinator muscle repair (proximal 1/3 dissection) - reapproximate supinator fibers (NOT MANDATORY - muscle heals spontaneously)
3. Hemostasis - meticulous cautery (avoid cautery near SRN or radial artery)

Superficial Layers:

1. Deep fascia closure - interrupted absorbable sutures (2-0 Vicryl)
2. Subcutaneous layer - interrupted absorbable sutures (3-0 Vicryl)
3. Skin closure - running subcuticular (4-0 Monocryl) or interrupted nylon sutures

Postoperative:

• Sugar tong splint (prevents forearm rotation) for 7-10 days
• Wound check at 1-2 weeks
• Early ROM at 2 weeks (wrist/elbow/finger motion to prevent stiffness)
• Radiographic follow-up at 2, 6, 12 weeks for union assessment

Indications (When to Use Henry Approach)

PRIMARY INDICATIONS:

1. Radial Shaft Fractures (MOST COMMON INDICATION):

• Displaced fractures with greater than 50% displacement or greater than 10° angulation
• Open fractures (Gustilo I-IIIA) with volar wound (contraindication if volar contamination - use posterior Thompson approach)
• Both-bone forearm fractures (Henry for radius, subcutaneous approach for ulna through SAME INCISION)
• Biomechanical advantage: Volar plating in TENSION (resists bending forces better than dorsal plating)

2. Radial Nonunion/Malunion:

• Nonunion with inadequate fixation or infection
• Malunion with functional impairment (loss of forearm rotation, reduced grip strength)
• Revision ORIF with bone grafting (iliac crest autograft or allograft)

3. Forearm Pathology:

• Radioulnar synostosis takedown (single volar approach reduces re-synostosis risk to 2% - Vince 1990)
• Radial osteotomy for angular deformity correction
• Tumor excision (osteoid osteoma, enchondroma, bone metastases)
• Infection (osteomyelitis with debridement and antibiotic cement spacer)
• Vascular injury (radial artery repair or reconstruction)

RELATIVE INDICATIONS:

• Minimally displaced fractures with progressive displacement on serial X-rays
• Fractures in polytrauma patients (facilitates early mobilization)
• Pathological fractures (tumor, infection, osteoporosis)

Contraindications (When NOT to Use Henry Approach)

ABSOLUTE CONTRAINDICATIONS:

• Open fractures with volar contamination (high infection risk - use posterior Thompson approach for debridement/fixation)
• Acute compartment syndrome requiring fasciotomy (use dorsal approach for 4-compartment fasciotomy, delay ORIF)

RELATIVE CONTRAINDICATIONS:

• Proximal radius fractures involving radial neck (higher PIN injury risk with supinator splitting - consider antegrade nailing or posterior approach)
• Distal radius metaphyseal fractures (consider volar plating via FCR approach - more direct distal exposure)
• Active soft tissue infection (volar cellulitis or abscess - delay surgery until infection controlled)

Outcomes

Union Rates:

• Isolated radius fractures: 95-98% union at 12-16 weeks (Chapman 1989)
• Both-bone fractures: 92-95% union (slightly lower due to higher energy mechanism)
• Nonunion rate: 2-3% (higher with inadequate fixation, smoking, NSAIDs)

Functional Outcomes:

• Forearm rotation: Mean 85-90% of contralateral side (limited by soft tissue scarring, NOT bone healing)
• Grip strength: Mean 90-95% of contralateral side at 12 months
• Return to work: Mean 12-16 weeks (manual labor), 6-8 weeks (sedentary work)

Complications:

• Nerve injury: 5-10% (SRN dysesthesia most common, 2% permanent - Ring 2004)
• Infection: 2-3% (superficial 2%, deep 0.5-1%)
• Nonunion: 2-3% (requires revision ORIF with bone grafting)
• Synostosis: 2-9% (2% single incision, 9% dual incision - Vince 1990)
• Hardware irritation: 10-15% (plate removal rate 10-12% at 12-18 months)

Intraoperative Complications

1. RADIAL ARTERY INJURY (0.5-1%):

Mechanism:

• Sharp dissection too close to artery (between BR and FCR)
• Aggressive lateral retraction of artery (excessive tension)
• Laceration during supinator splitting or periosteal elevation

Prevention:

• Use radial artery pulsation as LANDMARK (incise fascia lateral to artery)
• Mobilize artery MEDIALLY with BLUNT dissection (safer than lateral retraction)
• Control with vessel loops (NOT aggressive retractors)
• Avoid sharp dissection near artery (use blunt elevator)

Management:

• Recognition: Pulsatile bleeding from surgical field
• Immediate control: Direct pressure with gauze, then vascular clamps proximal/distal
• Repair options:
  • Primary repair (less than 1cm defect) - 6-0 or 7-0 Prolene interrupted sutures
  • Reverse interposition vein graft (greater than 1cm defect) - reverse saphenous vein or cephalic vein graft
  • Ligation (LAST RESORT) - only if hand perfusion via ulnar artery is adequate (Allen test positive, pulse oximetry on thumb adequate)
• Vascular surgery consultation MANDATORY for repair

Outcome:

• Primary repair: 95% patency at 6 months (Leversedge 2008)
• Ligation: 5% hand ischemia risk (median artery contribution variable)

2. POSTERIOR INTEROSSEOUS NERVE (PIN) INJURY (2-5% in Proximal Dissection):

Mechanism:

• Deep dissection through supinator in forearm pronation (PIN on deep surface)
• Excessive retraction around radial neck
• Direct trauma during periosteal elevation

Prevention:

• Place forearm in FULL SUPINATION during proximal dissection (migrates PIN anteriorly 4mm - Stern 1984)
• Split supinator in LINE OF ITS FIBERS (parallel to radius)
• Avoid deep dissection on dorsal radius (PIN lies on deep supinator surface)
• Minimize retraction around radial neck

Recognition:

• Decreased triggered EMG during supinator splitting (if neuromonitoring used)
• Postoperative finger/thumb extension weakness (EPL, EDC, EIP)
• Wrist extension preserved (ECRL/ECRB innervated by radial nerve proximal to PIN origin)

Management:

• Immediate: If recognized intraoperatively, release supinator and reposition retractors
• Postoperative palsy:
  • Observation for 3-6 months (90% spontaneous recovery - Ring 2004)
  • Dynamic splinting (tenodesis splint for finger/thumb extension)
  • Nerve exploration if no recovery by 6 months (neurolysis vs nerve grafting)
  • Tendon transfers if no recovery by 12 months (PT to ECRB, FCR to EDC, PL to EPL)

Outcome:

• 90% spontaneous recovery by 6 months
• Permanent deficit rare (less than 1%)

Postoperative Complications

1. SUPERFICIAL RADIAL NERVE (SRN) DYSESTHESIA (5-10%):

Mechanism:

• Excessive retraction during distal dissection
• Traction injury from retractors
• Electrocautery injury

Clinical Manifestation:

• Painful dysesthesia over dorsal thumb/index finger web space (SRN distribution)
• Painful neuroma at SRN injury site
• Hypersensitivity to light touch

Prevention:

• Identify SRN exiting from under BR (6-9cm proximal to styloid)
• Gentle MEDIAL retraction (avoid stretching)
• Avoid electrocautery near SRN
• Minimize retraction time (release retractors periodically)

Management:

• Transient dysesthesia (most cases):
  • Observation for 3-6 months (spontaneous resolution in 80%)
  • Desensitization therapy (massage, graded textures)
  • Neuropathic pain medications (gabapentin 300mg TDS, amitriptyline 25mg nocte)
• Persistent neuroma (2% cases):
  • Neuroma excision if symptoms persist beyond 6 months
  • Nerve transfer to deeper tissue (to avoid repeated trauma)
  • Consider nerve grafting if large nerve defect

Outcome:

• 80% resolve spontaneously by 6 months
• 2% permanent dysesthesia (Ring 2004)

2. NONUNION (2-3%):

Risk Factors:

• Inadequate fixation (less than 6 cortices proximal/distal)
• Excessive periosteal stripping (devascularizes fracture site)
• Smoking (10-fold increased nonunion risk)
• NSAIDs (COX-2 inhibitors safe, traditional NSAIDs increase nonunion risk)
• Infection (deep infection 5% nonunion risk)

Diagnosis:

• Persistent pain at fracture site beyond 4 months
• Radiographic: No bridging callus at 6 months, persistent fracture line, hardware loosening/failure

Management:

• Revision ORIF with bone grafting:
  • Remove failed hardware
  • Debride nonunion site to bleeding bone
  • Iliac crest autograft (gold standard) or allograft
  • Larger plate (3.5mm LCP with locking screws)
  • Longer fixation (8-10 cortices proximal/distal)
• Adjuncts: Bone morphogenetic protein (BMP-2 or BMP-7), low-intensity pulsed ultrasound (LIPUS)
• Smoking cessation: MANDATORY (10-fold reduced union rate if continued smoking)

Outcome:

• Revision ORIF with bone grafting: 85-90% union (Chapman 1989)
• Persistent nonunion: Vascularized bone graft (less than 5% cases)

3. RADIOULNAR SYNOSTOSIS (2-9%):

Risk Factors:

• Both-bone forearm fractures (vs isolated radius fracture)
• Proximal 1/3 fractures (interosseous membrane narrower proximally)
• High-energy mechanisms (Gustilo II-III open fractures)
• Head injury (heterotopic ossification risk)
• Delayed fixation (greater than 48 hours)
• Dual incision approach (9% vs 2% single volar incision - Vince 1990)

Clinical Manifestation:

• Progressive loss of forearm rotation (supination/pronation)
• Radiographic: Bone bridge between radius and ulna (usually proximal 1/3)

Prevention:

• Single volar incision for both-bone fractures (Henry for radius, subcutaneous for ulna)
• Preserve interosseous membrane (avoid dissection between bones)
• Prophylactic indomethacin 25mg TDS for 6 weeks (HIGH-RISK patients: head injury, proximal 1/3 fractures)
• Early fixation (within 48 hours)

Management:

• Observation if asymptomatic (minimal functional impairment)
• Synostosis excision if symptomatic:
  • Wait 12-18 months for maturation
  • Excise bone bridge
  • Interpose fat or silastic sheet (prevents recurrence)
  • Postoperative indomethacin 25mg TDS for 12 weeks
  • Aggressive ROM therapy

Outcome:

• Synostosis excision: 70-80% improved rotation (mean 40° gain)
• Recurrence rate: 15-20% (higher if excised before maturation)

4. INFECTION (2-3%):

Risk Factors:

• Open fractures (Gustilo II-III: 10-15% infection rate)
• Diabetes, smoking, immunosuppression
• Prolonged surgery (greater than 2 hours)
• Inadequate soft tissue coverage

Clinical Manifestation:

• Superficial (2%): Erythema, drainage from incision, no deep involvement
• Deep (0.5-1%): Persistent pain, fever, elevated CRP/ESR, purulent drainage, hardware loosening

Management:

• Superficial infection:
  • Oral antibiotics (flucloxacillin 500mg QDS or cephalexin 500mg QDS for 10-14 days)
  • Wound care (daily dressings)
  • Close monitoring (watch for progression to deep infection)
• Deep infection:
  • Irrigation and debridement (I&D) - remove necrotic tissue, cultures for microbiology
  • Hardware retention if fracture healing progressing (biofilm formation common, but removal risks nonunion)
  • Hardware removal if nonunion or loose hardware (debridement + antibiotic cement spacer + revision ORIF after infection cleared)
  • IV antibiotics (6 weeks minimum) - guided by culture sensitivities (common: S. aureus, coagulase-negative staphylococci)

Outcome:

• Superficial infection: 95% resolution with oral antibiotics
• Deep infection with hardware retention: 70-80% infection clearance (Zimmerli 2004)
• Deep infection with hardware removal: 90-95% infection clearance (but nonunion risk if premature removal)