Humeral Shaft Fracture

1. Clinical Overview

Summary

Humeral shaft fractures represent 3-5% of all adult fractures and are defined as fractures occurring between the surgical neck proximally and the supracondylar ridge distally. [1,2] These fractures occupy a unique position in orthopaedic trauma where conservative management remains the gold standard for the majority of isolated, closed injuries, achieving union rates exceeding 90% with excellent functional outcomes. [3,4]

The Sarmiento functional bracing protocol, introduced in the 1970s, revolutionized treatment by demonstrating that rigid immobilization is unnecessary and that controlled fracture motion promotes healing through abundant callus formation. [5] The functional brace utilizes hydrostatic compression of the soft tissue envelope to stabilize the bone while permitting early shoulder and elbow motion, preventing joint stiffness.

However, specific absolute indications for surgical intervention include open fractures, vascular injury requiring repair, floating elbow (ipsilateral forearm fracture), polytrauma, bilateral humeral fractures, and pathological fractures. [6,7]

The radial nerve, which spirals around the posterior humeral shaft in the spiral groove between the lateral and medial triceps heads, is at significant risk of injury, particularly in distal third spiral fractures (Holstein-Lewis pattern). [8,9] Radial nerve palsy complicates 11-18% of humeral shaft fractures, though the vast majority (90%) represent neuropraxia with spontaneous recovery within 3-4 months. [10]

Key Facts

• Incidence: 3-5% of all adult fractures, approximately 13 per 100,000 population annually [1,2]
• Bimodal Distribution: Young males (high-energy trauma) and elderly females (low-energy falls, osteoporosis) [2]
• Most Common Nerve Injury: Radial nerve (11-18%), causing wrist drop and inability to extend fingers/thumb [8,9,10]
• Conservative Success Rate: 90-95% union with functional bracing in isolated closed fractures [3,4,5]
• Acceptable Deformity: Due to shoulder ball-and-socket joint compensation:
  • 20° Anterior/Posterior Angulation
  • 30° Varus/Valgus Angulation
  • 3cm Shortening
  • 15-20° Rotational Malalignment [11]
• Non-union Rate: 5-10% with conservative treatment, higher with certain surgical techniques [12,13]

Clinical Pearls

"The Wrist Drop Rule": ALWAYS document radial nerve function (wrist extension, finger extension, thumb extension, first web space sensation) BEFORE any manipulation or intervention. If radial nerve palsy is present before reduction, manage expectantly with observation. If palsy develops AFTER manipulation, consider nerve entrapment and surgical exploration. [10]

"Gravity is the Aligning Force": The success of functional bracing depends on allowing gravity to act as the deforming force. The arm MUST hang freely. Patients who rest their elbow on armrests or tables push the distal fragment proximally, creating varus deformity and shortening. Patient education is critical.

"The Floating Elbow": Ipsilateral humeral shaft and forearm fractures create a mechanically unstable "flail" upper limb. This combination is an absolute indication for surgical fixation of the humerus to restore limb stability and allow functional use. [14]

"Holstein-Lewis Trap": Distal third spiral fractures have the highest rate of radial nerve injury (up to 20%) because the nerve is tethered at the lateral intermuscular septum 10cm proximal to the lateral epicondyle. As the distal fragment displaces proximally, it traps the nerve against the septum or between fracture fragments. [8,15]

"Primary vs Iatrogenic Palsy": Primary radial nerve palsy (present at presentation) has a 90% spontaneous recovery rate and is managed expectantly. Iatrogenic palsy (occurring after manipulation or surgery) has a much lower recovery rate and often requires early exploration. [10]

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2. Epidemiology

Demographics

Humeral shaft fractures demonstrate a characteristic bimodal age distribution:

• Young Adults (20-40 years): Predominantly males involved in high-energy trauma (motor vehicle accidents, falls from height, direct blows, sports injuries) [1,2]
• Elderly (> 65 years): Predominantly females with osteoporosis sustaining low-energy falls from standing height [2]

Incidence

• Overall Incidence: 13 per 100,000 population per year [1]
• All Fractures: Represents 3-5% of all adult fractures [1,2]
• Humeral Fractures: Accounts for 20% of all humeral fractures (proximal, shaft, distal combined) [2]

Mechanism of Injury

The fracture pattern correlates strongly with the mechanism:

1. Direct Trauma (Motor vehicle accident, assault, direct blow):

• Creates transverse or comminuted fracture patterns (AO Type A3 or C)
• Higher energy typically required
• Greater soft tissue injury
• Higher rate of open fractures

2. Indirect Trauma (Fall on outstretched hand, twisting injury):

• Creates spiral or oblique fracture patterns (AO Type A1 or A2)
• Lower energy mechanism
• Typical in elderly with osteoporotic bone
• Classic in arm wrestling injuries (violent muscle contraction) [16]

3. Pathological Fractures:

• Metastatic disease (breast, lung, kidney, thyroid, prostate)
• Multiple myeloma
• Osteoporosis with minimal trauma
• Bone cysts, fibrous dysplasia (younger patients)

Associated Injuries

• Ipsilateral forearm fracture: 5-10% (Floating elbow) [14]
• Ipsilateral shoulder injuries: Rotator cuff tears, glenohumeral dislocation
• Chest trauma: Rib fractures, pneumothorax (high-energy mechanisms)
• Polytrauma: Head injury, pelvic fractures, long bone fractures

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3. Pathophysiology

Surgical Anatomy

The Humeral Shaft

The humeral shaft is defined as the region between:

• Proximal Boundary: Surgical neck (insertion of pectoralis major)
• Distal Boundary: Supracondylar ridge (2cm proximal to olecranon fossa)

The shaft can be divided into thirds for descriptive purposes:

• Proximal Third: Rotator cuff insertions, axillary nerve proximity
• Middle Third: Primary zone for functional bracing, optimal for plating
• Distal Third: Radial nerve vulnerability, Holstein-Lewis zone

The Radial Nerve - Critical Surgical Anatomy

The radial nerve is the structure at greatest risk:

Course:

1. Originates from posterior cord of brachial plexus (C5-T1)
2. Passes posterior to brachial artery in axilla
3. Enters posterior compartment between long and medial heads of triceps
4. Winds around posterior humeral shaft in spiral groove (between lateral and medial triceps heads)
5. Pierces lateral intermuscular septum (LIMS) approximately 10cm proximal to lateral epicondyle
6. Enters anterior compartment between brachialis and brachioradialis
7. Divides into superficial (sensory) and posterior interosseous (motor) branches at elbow level

Zone of Vulnerability:

• The nerve is tethered at two points:
  • Arcade of Frohse (distal)
  • Lateral intermuscular septum (proximal - most relevant for shaft fractures)
• Tethering creates fixed point where traction injury occurs
• Distal third fractures trap nerve between fragments or against septum [8,9,15]

Motor Supply (relevant for examination):

• Triceps (above spiral groove - spared in shaft fractures)
• Brachioradialis
• Extensor carpi radialis longus (ECRL)
• Extensor carpi radialis brevis (ECRB)
• Posterior interosseous nerve → Extensor digitorum communis (EDC), Extensor pollicis longus (EPL), Extensor indicis, Extensor carpi ulnaris

Sensory Supply:

• Posterior arm (posterior cutaneous nerve of arm)
• Dorsal forearm (posterior cutaneous nerve of forearm)
• First dorsal web space (superficial radial nerve) - KEY SENSORY TEST

Deforming Muscular Forces

Understanding deforming forces guides closed reduction:

Proximal Third Fractures:

• Proximal Fragment: Abducted and externally rotated (rotator cuff - supraspinatus, infraspinatus)
• Distal Fragment: Adducted (pectoralis major, latissimus dorsi, teres major) and pulled medially (deltoid)

Middle Third Fractures:

• Proximal Fragment: Adducted (pectoralis major insertion)
• Distal Fragment: Pulled proximally and laterally (deltoid insertion)

Distal Third Fractures:

• Proximal Fragment: Abducted (deltoid)
• Distal Fragment: Pulled proximally (biceps, brachialis anteriorly; triceps posteriorly)

Fracture Healing in the Humerus

The humerus has exceptional healing capacity due to:

• Rich Vascular Supply: Nutrient artery, periosteal vessels, extensive soft tissue envelope
• Abundant Muscle Coverage: Provides blood supply and mechanical stability
• Low Mechanical Demands: Upper limb is non-weight bearing
• Motion Stimulation: Controlled micromotion at fracture site promotes callus formation [5]

Healing Timeline:

• Weeks 0-2: Hematoma, inflammation, granulation tissue
• Weeks 2-6: Soft callus formation (visible radiographically)
• Weeks 6-12: Hard callus, bridging bone
• Months 3-12: Remodeling, cortical reconstitution

Factors Promoting Union:

• Early functional loading (Sarmiento principle) [5]
• Good soft tissue envelope
• Adequate blood supply
• Patient compliance with bracing protocol

Risk Factors for Non-union:

• Transverse fracture pattern (distraction, minimal contact) [12,13]
• Soft tissue interposition
• Smoking [13]
• Diabetes
• NSAIDs (controversial)
• Inadequate immobilization
• Infection (in open/surgical cases)
• Pathological bone

Holstein-Lewis Fracture - Special Pathophysiology

Definition: Spiral fracture of the distal third of the humeral shaft [15]

Mechanism:

• Torsional force applied to arm
• Spiral fracture propagates distally
• Distal fragment migrates proximally due to muscle pull
• Radial nerve entrapment: As fragment migrates, nerve is caught:
  • Between fracture fragments
  • Against lateral intermuscular septum
  • Against bone spike or edge

Clinical Significance:

• Highest rate of radial nerve injury: Up to 20% (versus 11-13% overall) [8,15]
• Mechanism of injury: Traction, laceration, or contusion
• Prognosis: If nerve intact at presentation, most recover spontaneously
• Surgical Consideration: If nerve palsy develops after manipulation, exploration indicated

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4. Clinical Presentation

History

Mechanism of Injury: Essential for determining fracture pattern and energy

• High-energy: Motor vehicle accident, fall from height, assault
• Low-energy: Simple fall, twisting injury, arm wrestling
• Pathological: Minimal trauma, history of cancer, bone pain prior to fracture

Symptoms:

• Pain: Severe, localized to mid-arm
• Deformity: Visible angulation, shortening
• Swelling: Rapid onset, may be massive in high-energy injuries
• Inability to Use Arm: "Floppy arm", inability to lift or move
• Wrist Drop: May be noticed immediately (indicates radial nerve injury)

Red Flag Questions:

• "Can you lift your wrist up?" (radial nerve - wrist extension)
• "Can you straighten your fingers?" (radial nerve - finger extension)
• "Did you feel any tingling or numbness?" (nerve injury)
• "Is the arm getting tighter?" (compartment syndrome - rare but possible)
• Any prior cancer history? (pathological fracture)

Examination

General Inspection:

• Obvious deformity, swelling, ecchymosis
• Open wound (open fracture classification)
• Skin tenting (may threaten skin viability)

Palpation:

• Tenderness localized to fracture site
• Crepitus
• Abnormal mobility
• Compartment assessment (rare, but assess anterior and posterior compartments)

Neurovascular Examination - CRITICAL

Radial Nerve Assessment (Document BEFORE any intervention):

Motor:

• Brachioradialis: Resistance to elbow flexion with forearm mid-prone position
• Wrist Extension: Patient extends wrist against resistance (ECRL/ECRB) - KEY TEST
• Finger Extension at MCP Joints: Extend fingers against resistance (EDC) - KEY TEST
• Thumb Extension: Thumb-up position, extend thumb at IP and MCP joints (EPL)
• Abductor Pollicis Longus: Thumb abduction in plane perpendicular to palm

Sensory:

• First Dorsal Web Space: Pinprick or light touch sensation - ANATOMICAL SNUFFBOX region - KEY SENSORY TEST
• Dorsal forearm (less specific)

Grading (if palsy present):

• Document as "Radial Nerve Palsy - complete wrist and finger drop" or "Partial - weak extension"
• Document TIMING: "Present on arrival" vs "Developed after manipulation"

Median Nerve (Less commonly affected):

• Motor: Thumb opposition (opponens pollicis), APB (thumb palmar abduction)
• Sensory: Palmar thumb, index, middle finger

Ulnar Nerve (Rarely affected in shaft fractures):

• Motor: Finger abduction/adduction (interossei), Froment's sign
• Sensory: Little finger, ulnar half of ring finger

Vascular Assessment:

• Radial Pulse: Palpate at wrist - DOCUMENT
• Ulnar Pulse: Palpate at wrist
• Capillary Refill: less than 2 seconds
• Hand Perfusion: Warm, pink, normal sensation
• Brachial Artery: Rarely injured but assess if vascular compromise suspected

Range of Motion:

• Shoulder: Assess gently if patient can tolerate
• Elbow: Document baseline ROM
• Wrist/Hand: Full ROM if nerve intact

Associated Injuries:

• Examine shoulder (dislocation, AC joint injury)
• Examine elbow (dislocation, fracture)
• Examine forearm and wrist (floating elbow)
• Examine chest (rib fractures in high-energy trauma)

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5. Investigations

Radiological Imaging

X-Ray (First-Line Investigation)

Standard Views:

• AP (Anteroposterior) of Humerus: Full length, including shoulder and elbow joints
• Lateral of Humerus: True lateral, full length including both joints

Why Include Joints?:

• Rule out associated shoulder injuries (fracture, dislocation)
• Rule out elbow injuries (fracture, dislocation)
• Assess for "floating elbow" (ipsilateral forearm fracture)
• Plan for potential surgical approaches

Radiographic Assessment:

• Fracture Location: Proximal, middle, or distal third
• Fracture Pattern: Transverse, oblique, spiral, comminuted (see Classification)
• Displacement: Degree of angulation (AP and lateral planes), shortening, rotation
• Comminution: Simple vs complex
• Bone Quality: Osteopenia, lytic lesions (pathological), bone cysts

Acceptable Alignment on X-Ray (for conservative management):

• less than 20° angulation in AP plane (coronal)
• less than 20° angulation in lateral plane (sagittal)
• less than 30° varus/valgus
• less than 3cm shortening
• less than 20° rotation (clinical assessment - compare thumb position with arm hanging)

CT Scan

Indications:

• Suspected pathological fracture: To characterize lytic lesion, assess cortical destruction
• Complex fracture patterns: Severe comminution requiring surgical planning
• Intra-articular extension: Extension into shoulder or elbow joint
• Pre-operative planning: For complex reconstructions, plating strategies

MRI

Indications (Rare):

• Suspected pathological fracture: To assess marrow involvement, soft tissue mass
• Vascular injury assessment: MR angiography if conventional angiography not available
• Nerve injury assessment: In select cases with complex nerve injury

Angiography

Indications:

• Absent pulses with suspicion of brachial artery injury [17]
• Hard signs of vascular injury (expanding hematoma, pulsatile bleeding, bruit/thrill)
• May use CT angiography as first-line in stable patients

Laboratory Investigations

Routine:

• Full Blood Count: Baseline hemoglobin (blood loss assessment)
• Coagulation Profile: If anticoagulated or surgical planning
• Group and Save: If surgery anticipated

Pathological Fracture Workup (if suspected):

• Calcium, Phosphate, ALP: Bone profile
• Protein Electrophoresis: Multiple myeloma
• PSA: Prostate cancer (males)
• Thyroid Function: Thyroid metastases
• Tumor Markers: Based on suspected primary

Open Fracture:

• Inflammatory Markers: Baseline CRP (for monitoring infection)
• Wound Cultures: Intraoperative deep tissue cultures

Neurophysiological Studies

Electromyography (EMG) and Nerve Conduction Studies (NCS):

Indications:

• Radial nerve palsy with no clinical recovery by 6-8 weeks [10]
• Differentiate neuropraxia (good prognosis) from axonotmesis/neurotmesis (poor prognosis)
• Guide decision for surgical exploration vs continued observation

Timing:

• Not useful acutely (first 3 weeks) - Wallerian degeneration not yet established
• Optimal timing: 6-8 weeks post-injury
• Repeat studies: At 12 weeks if initial study equivocal

Findings:

• Neuropraxia: Conduction block, intact distal responses (good prognosis)
• Axonotmesis: Absent distal responses, denervation (slow recovery expected)
• Neurotmesis: Complete nerve disruption (no recovery without repair)

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6. Classification Systems

AO/OTA Classification (Most Widely Used) [18]

The AO classification for humeral shaft fractures (12-A, 12-B, 12-C) categorizes fractures by complexity:

Type A: Simple Fractures (Two Fragments)

• A1 - Spiral: Torsional injury, oblique fracture line > 2x diameter
  • A1.1: Proximal zone
  • A1.2: Middle zone
  • A1.3: Distal zone (Holstein-Lewis if spiral)
• A2 - Oblique: Fracture line 30-90°, length less than 2x diameter
  • A2.1: Proximal oblique
  • A2.2: Middle oblique
  • A2.3: Distal oblique
• A3 - Transverse: Fracture line less than 30° to shaft axis
  • A3.1: Proximal transverse
  • A3.2: Middle transverse
  • A3.3: Distal transverse

Clinical Relevance: Type A fractures generally amenable to conservative management if displacement acceptable. Transverse patterns (A3) have higher non-union risk due to distraction forces.

Type B: Wedge Fractures (Three Fragments)

• B1 - Spiral Wedge: Torsional injury with separate wedge fragment
• B2 - Bending Wedge: Angular force creating wedge
• B3 - Fragmented Wedge: Wedge itself is comminuted

Clinical Relevance: Wedge fragments may compromise stability. May still be amenable to conservative management if overall alignment acceptable.

Type C: Complex Fractures (> 3 Fragments)

• C1 - Spiral Comminution: Multiple spiral fragments
• C2 - Segmental: Two separate fracture lines creating floating segment
• C3 - Complex Irregular: Severe comminution, irregular pattern

Clinical Relevance: Type C fractures, particularly segmental (C2), often require surgical fixation due to instability and difficulty achieving acceptable alignment conservatively.

Descriptive Classification Elements

Location:

• Proximal third
• Middle third
• Distal third

Pattern:

• Transverse
• Oblique
• Spiral
• Comminuted
• Segmental

Displacement:

• Non-displaced (less than 5mm, less than 5° angulation)
• Minimally displaced
• Displaced (specify degree of angulation, shortening, rotation)

Open vs Closed (Gustilo-Anderson for open fractures):

• Type I: less than 1cm wound, minimal contamination, low energy
• Type II: > 1cm wound, moderate contamination
• Type III: High energy, extensive soft tissue damage
  • IIIA: Adequate soft tissue coverage
  • IIIB: Inadequate coverage, requires flap
  • IIIC: Vascular injury requiring repair

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7. Management Algorithm

                    HUMERAL SHAFT FRACTURE
                             ↓
                   INITIAL ASSESSMENT
              (Neurovascular Status, Open/Closed)
                             ↓
              ┌──────────────┴──────────────┐
         ABSOLUTE SURGICAL              NO ABSOLUTE
          INDICATIONS?                  INDICATIONS
    (Open, Vascular, Floating              ↓
     Elbow, Polytrauma,              ISOLATED INJURY
     Bilateral, Pathological)               ↓
              ↓                        X-RAY ASSESSMENT
         EMERGENCY                          ↓
          SURGERY              ┌────────────┴────────────┐
              ↓              ACCEPTABLE              UNACCEPTABLE
    ┌─────────┴─────────┐   ALIGNMENT?               ALIGNMENT?
  OPEN      VASCULAR/   (≤20° AP/Lat,            (> 20° angulation,
 FRACTURE   POLYTRAUMA   ≤30° varus,              > 30° varus,
    ↓           ↓        ≤3cm short)               > 3cm short)
Debride +   Urgent           ↓                         ↓
  ORIF      Fixation    CLOSED                   CLOSED REDUCTION
              ↓         REDUCTION                  + RE-X-RAY
         FIXATION            ↓                         ↓
         (Plate      ┌───────┴───────┐        ┌────────┴────────┐
          or Nail)   ACCEPTABLE     UNSTABLE   ACCEPTABLE    STILL
                     REDUCTION?     FRACTURE   REDUCTION   UNACCEPTABLE
                         ↓              ↓          ↓             ↓
                    CONSERVATIVE   CONSIDER   CONSERVATIVE   SURGICAL
                     MANAGEMENT    SURGICAL    MANAGEMENT    FIXATION
                         ↓         FIXATION        ↓             ↓
                   ┌─────┴─────┐      ↓      U-Slab 0-2wks  Plate vs Nail
                 Week 0-2    Week 2-12      Brace 2-12wks
                 U-SLAB      FUNCTIONAL
                (Hanging     BRACE
                  Cast)     (Sarmiento)
                             ↓
                    WEEKLY X-RAYS x3
                    THEN 2-WEEKLY
                             ↓
                    CLINICAL + RADIO
                        UNION?
                ┌────────┴────────┐
               YES               NO
                ↓                ↓
            MOBILIZE        NON-UNION
            DISCHARGE         SURGERY
                          (Plate + Graft)

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8. Management Protocols

1. Conservative Management - The Sarmiento Protocol (GOLD STANDARD) [5]

Conservative management with functional bracing remains the treatment of choice for the majority of closed, isolated humeral shaft fractures with acceptable or reducible alignment. This protocol has demonstrated 90-95% union rates with excellent functional outcomes. [3,4,5]

Phase 1: Weeks 0-2 - Hanging Cast/U-Slab

Objective: Initial fracture stabilization, pain control, early alignment

Technique:

• Apply coaptation splint (U-slab) or hanging cast:
  • Plaster/fiberglass from shoulder around elbow, up medial arm
  • Well-padded, especially over olecranon and epicondyles
  • Collar and cuff support OR
  • Hanging cast with wrist strap (controversial - may distract fracture)

Hanging Cast Principle:

• Weight of cast provides traction to reduce shortening
• Arm MUST hang freely - no elbow support on armrest
• Patient sleeps semi-recumbent (recliner or multiple pillows)
• Caution: Excessive weight can distract transverse fractures → non-union

Instructions to Patient:

• Keep arm hanging at side at all times
• Sleep upright (30-45° incline minimum)
• Pendulum shoulder exercises (gentle, pain-free)
• Active elbow, wrist, hand exercises
• NO lifting, pushing, pulling

Follow-up:

• Week 1: Clinical review, check neurovascular status, X-ray to confirm alignment
• Week 2: X-ray to assess early callus, transition to functional brace

Phase 2: Weeks 2-12 - Functional Brace

Objective: Promote fracture healing through controlled micromotion while maintaining alignment

Sarmiento Functional Brace:

• Design: Pre-fabricated or custom thermoplastic shell (anterior and posterior components)
• Fit: Extends from 2cm below axilla to 2cm above elbow
• Mechanism: Hydrostatic compression of soft tissue envelope stabilizes underlying bone cylinder
• Advantages: Allows full shoulder and elbow motion, prevents joint stiffness

Application Technique:

• Apply over stockinette or thin padding
• Tighten circumferentially to provide compression (should be snug but not compromise circulation)
• Velcro straps allow patient to adjust tightness (swelling decreases over time)
• Check neurovascular status after application

Functional Bracing Principles (Sarmiento's Concepts):

• Motion Promotes Healing: Controlled micromotion at fracture site stimulates callus
• Soft Tissue Stabilization: Muscles act as "biological splint"
• Gravity Alignment: Dependent arm uses weight as aligning force
• Hypertrophic Callus: Expect abundant callus (different from lower limb)

Patient Instructions:

• Wear brace 24 hours/day (remove only for hygiene, retighten after)
• Arm hangs freely - NO elbow support on surfaces
• Active shoulder pendulums → progress to forward flexion, abduction
• Active elbow flexion/extension
• Wrist and hand exercises
• Critical: No lifting, no pushing doors, no carrying objects for first 6 weeks

Follow-up Protocol:

• Weeks 2, 3, 4: Weekly X-rays to monitor alignment (expect some settling)
• Weeks 6, 8, 10, 12: Bi-weekly X-rays
• Clinical union: No pain with palpation, able to use arm against gravity
• Radiological union: Bridging callus on 3/4 cortices

Expected Alignment Changes:

• Some varus drift is common and acceptable (up to 30°)
• Shortening up to 2-3cm acceptable
• If alignment exceeds acceptable parameters → consider surgical fixation

Phase 3: Weeks 12+ - Rehabilitation and Brace Weaning

Union Assessment (typically 8-12 weeks):

• Clinical: No tenderness, able to lift arm against resistance
• Radiological: Bridging callus visible on AP and lateral X-rays

Brace Weaning:

• Gradual wean over 2-4 weeks
• Start removing brace for increasing periods during day
• Continue night-time wear until confident
• Progress functional activities

Physiotherapy:

• Shoulder strengthening (rotator cuff, deltoid)
• Elbow strengthening
• Proprioception and coordination exercises
• Return to functional activities

Return to Activities:

• Light activities: 12 weeks
• Heavy manual labor: 16-20 weeks
• Contact sports: 20-24 weeks (with radiological confirmation of mature union)

Conservative Management - Success Rates and Outcomes

Union Rates: 90-95% in appropriately selected patients [3,4,5]

Functional Outcomes:

• Excellent shoulder and elbow range of motion
• Minimal functional deficit in activities of daily living
• High patient satisfaction [3,4]

Predictors of Success:

• Patient compliance with protocol
• Appropriate fracture pattern (not severely comminuted)
• Acceptable initial alignment or reducible
• Non-smoker
• No significant osteoporosis

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2. Surgical Management - Indications and Techniques

Absolute Indications for Surgery

1. Open Fractures (All grades - Gustilo-Anderson I, II, III)
2. Vascular Injury requiring arterial repair
3. Floating Elbow (ipsilateral forearm fracture) [14]
4. Bilateral Humeral Shaft Fractures (patient needs one functional arm)
5. Polytrauma (patient needs upper limbs for mobility aids, transfers)
6. Segmental Fractures (unstable, difficult to brace)
7. Pathological Fractures (impending or complete)
8. Brachial Plexus Injury (combined ipsilateral injuries)

Relative Indications for Surgery

1. Failure of Conservative Management:
   • Unacceptable alignment despite closed reduction
   • Loss of alignment in brace
   • Non-union (after 4-6 months of conservative treatment) [12,13]
2. Radial Nerve Palsy Developing AFTER Manipulation (potential entrapment) [10]
3. Patient Factors:
   • Non-compliant patient unlikely to adhere to bracing protocol
   • Morbid obesity (brace ineffective)
   • Patient preference after informed discussion
4. Fracture Factors:
   • Severe soft tissue injury (though not open)
   • Severe comminution (Type C3)

   • 3cm shortening not reducible

Surgical Technique 1: Compression Plating (ORIF) - GOLD STANDARD FOR SURGERY

Implant: 4.5mm Narrow or Broad Dynamic Compression Plate (DCP) or Locking Compression Plate (LCP)

Principle: Absolute stability through compression → primary bone healing without callus

Surgical Approaches:

Anterolateral Approach (Proximal and Middle Third):

• Position: Supine, arm on side table
• Incision: Along lateral border of biceps
• Internervous Plane: Between biceps (musculocutaneous nerve) and brachialis (musculocutaneous) / brachioradialis (radial nerve)
• Advantages: Extensile, good exposure, radial nerve identified distally
• Radial Nerve: Identify as it pierces lateral intermuscular septum distally, protect throughout

Posterior Approach (Middle and Distal Third):

• Position: Lateral decubitus or prone
• Incision: Posterior midline arm
• Dissection: Split triceps in midline or reflect laterally (triceps-reflecting approach)
• Advantages: Direct access to radial nerve in spiral groove, excellent for distal third
• Radial Nerve: Identify in spiral groove, mobilize and protect

Technique:

1. Approach and expose fracture site
2. Identify and protect radial nerve throughout procedure
3. Reduce fracture anatomically:
   • Restore length, rotation, alignment
   • Use reduction clamps, pointed reduction forceps
4. Apply plate to tension side (anterolateral surface preferred)
5. Screw Fixation:
   • Minimum 6 cortices (3 bicortical screws) proximal and distal to fracture
   • Span Rule: Plate length should span at least 3x fracture length
   • Consider interfragmentary lag screw for oblique/spiral patterns (in addition to plate)
6. Ensure compression across fracture site
7. Copious irrigation, meticulous hemostasis
8. Layered closure, drain if needed

Post-operative Protocol:

• Sling for comfort (1-2 weeks)
• Early shoulder pendulums, elbow ROM
• No lifting > 5kg for 6 weeks
• Progressive strengthening 6-12 weeks
• X-rays at 2, 6, 12 weeks

Outcomes:

• Union rate: 95-98%
• Time to union: 12-16 weeks
• Complications: Radial nerve injury (iatrogenic 3-5%), infection (1-3%), non-union (2-5%)

Surgical Technique 2: Intramedullary Nailing

Implant: Humeral IM nail (antegrade or retrograde)

Indications (Limited):

• Pathological fractures (entire bone at risk, load-sharing device)
• Segmental fractures
• Bilateral humeral fractures (faster bilateral fixation)

Contraindications:

• Active shoulder pathology (rotator cuff tear - antegrade nail violates cuff)
• Narrow medullary canal (less than 6mm)
• Very distal or proximal fractures (inadequate fixation length)

Antegrade Nailing Technique:

• Entry Point: Proximal humerus, lateral to bicipital groove (violates rotator cuff insertion)
• Position: Beach chair, C-arm fluoroscopy
• Technique: Guidewire, ream canal (1-2mm larger than nail), insert nail, proximal and distal locking screws
• Disadvantage: Rotator cuff morbidity - shoulder pain, stiffness in 20-30% of patients [6,7]

Retrograde Nailing Technique:

• Entry Point: Olecranon fossa (risks elbow stiffness, heterotopic ossification)
• Position: Supine, elbow flexed
• Disadvantage: Elbow complications, less commonly performed

Outcomes:

• Union rate: 85-90% (lower than plating) [6,7]
• Time to union: 16-20 weeks
• Complications: Shoulder pain (antegrade - 20-30%), non-union (10-15%), malrotation, nail prominence

Current Consensus: Plating superior to nailing for humeral shaft fractures in terms of union rate and functional outcomes. Nailing reserved for specific indications (pathological fractures, bilateral injuries). [6,7]

Surgical Technique 3: External Fixation

Indications (Rare):

• Severe open fractures (Gustilo IIIB/C) with massive soft tissue loss
• Severe contamination requiring delayed definitive fixation
• Damage control orthopaedics in polytrauma
• Vascular repair requiring stabilization

Technique: Uniplanar or multiplanar external fixator with pins in proximal and distal fragments

Definitive vs Temporary: Usually temporary (convert to plate/nail once soft tissues stabilized)

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3. Management of Specific Scenarios

Radial Nerve Palsy [10]

Primary Palsy (Present at Presentation):

Incidence: 11-18% of humeral shaft fractures [8,9,10]

Mechanism:

• Neuropraxia (most common - 90%): Contusion, traction, compression
• Axonotmesis (uncommon): Partial disruption
• Neurotmesis (rare in closed fracture): Complete transection

Management - EXPECTANT:

• Observation: 90% spontaneous recovery within 3-4 months
• Splinting: Dynamic wrist extension splint (prevent wrist/finger flexion contractures)
• Physiotherapy: Passive ROM exercises, prevent joint stiffness
• EMG/NCS: At 6-8 weeks if no clinical recovery (prognostic information)
• Exploration: Consider at 3-4 months if no recovery and EMG shows neurotmesis
• Functional outcome: Most patients regain full or near-full function

CLOSED FRACTURE WITH PRIMARY PALSY = OBSERVE (DO NOT EXPLORE ACUTELY)

Secondary Palsy (Develops After Manipulation/Reduction):

Incidence: 3-5% after closed reduction

Mechanism: Nerve entrapment between fracture fragments, traction during manipulation

Management - CONSIDER EARLY EXPLORATION:

• High suspicion for nerve entrapment
• Surgical exploration within 1-2 weeks
• Intraoperative findings: Free nerve, remove entrapped fragments, consider neurolysis
• If nerve transected: Primary repair or nerve graft

SECONDARY PALSY POST-REDUCTION = STRONG CONSIDERATION FOR EXPLORATION

Radial Nerve Palsy with Open Fracture:

Management: Surgical exploration mandatory (debridement required anyway)

• Inspect nerve intraoperatively
• If intact: Observe
• If lacerated/transected: Primary repair or tag for delayed nerve graft

Radial Nerve Palsy with Operative Indication (for other reasons):

Management: Explore nerve during surgery

• Identify nerve, ensure not entrapped
• If iatrogenic injury during surgery: Immediate repair

Holstein-Lewis Fracture [8,15]

Definition: Distal third spiral fracture with high radial nerve injury risk

Management:

• If nerve intact: Conservative management as per standard protocol
• If radial nerve palsy present at presentation: Observe (as per primary palsy protocol)
• If radial nerve palsy develops after manipulation: Strong consideration for exploration
• Surgical fixation (if indicated for other reasons): Posterior approach, identify and protect nerve

Floating Elbow [14]

Definition: Ipsilateral humeral shaft and forearm (radius/ulna) fractures

Mechanism: High-energy injury, creates mechanically unstable "flail" upper limb

Management - ABSOLUTE SURGICAL INDICATION:

• Fix humerus first (provides stable base)
• Fix forearm (plate both radius and ulna if both fractured)
• Allows early mobilization, prevents joint stiffness
• Conservative management of humerus contraindicated (unstable linkage)

Open Fractures

Management - Gustilo-Anderson Protocol:

• Immediate: IV antibiotics (Cefazolin + Gentamicin, add Penicillin if soil contamination)
• Within 6 hours: Surgical debridement
  • Extend wound, excise devitalized tissue
  • Copious pulsatile lavage (> 6L saline)
  • Remove contamination
  • Stabilize fracture (plate or external fixator)
• Type I/II: Consider primary closure
• Type IIIA: Delayed primary closure or split-thickness skin graft
• Type IIIB/C: External fixator, staged reconstruction, flap coverage
• Repeat debridement: 24-48 hours if needed
• Antibiotics: Continue 24-72 hours based on contamination

Pathological Fractures

Impending Fracture (Lytic lesion > 50% cortical destruction, > 2.5cm size):

• Prophylactic fixation (prevents fracture)
• IM nail (protects entire bone) preferred over plate
• Consider adjuvant treatment (radiotherapy, cementation)

Complete Pathological Fracture:

• Surgical fixation (IM nail or long plate with cement augmentation)
• Treat underlying malignancy (oncology referral)
• Prognosis depends on primary cancer

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9. Complications

Early Complications

1. Radial Nerve Palsy

Covered extensively above [10]

2. Vascular Injury (Rare - less than 2%)

Brachial Artery Injury:

• Presentation: Absent radial/ulnar pulses, cool pale hand, prolonged capillary refill
• Mechanism: Direct laceration (bone spike), contusion, traction
• Investigation: Angiography (CT or conventional)
• Management:
  • Emergency vascular surgery: Exploration, repair, vein graft if needed
  • Stabilize fracture (external fixator or plate)
  • Fasciotomy if prolonged ischemia (> 6 hours)
• Prognosis: Good if repaired within 6-8 hours; risk of limb loss if delayed [17]

3. Compartment Syndrome (Rare in Humerus)

Presentation: Progressive pain out of proportion, pain with passive stretch, tense compartments, paresthesias

Diagnosis: Clinical (do not wait for absent pulses or paralysis)

Management:

• Emergency fasciotomy: Anterior and posterior compartments
• Release all compartments (volar, dorsal, mobile wad in forearm if involved)
• Stabilize fracture
• Delayed wound closure or skin graft

4. Infection (in Open/Surgical Cases)

Superficial Wound Infection:

• Cellulitis, wound discharge
• Management: Antibiotics (Flucloxacillin or Clindamycin), wound care

Deep Infection/Osteomyelitis:

• Persistent drainage, systemic symptoms, elevated inflammatory markers
• Management: Surgical debridement, culture-directed IV antibiotics (6 weeks), retain fixation if stable

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Late Complications

1. Non-Union [12,13]

Definition: Failure of fracture to unite by 6 months, no radiographic progression of healing for 3 months

Incidence:

• Conservative management: 5-10%
• Plate fixation: 2-5%
• IM nailing: 10-15% (higher than plate) [6,7,12,13]

Risk Factors:

• Fracture pattern: Transverse fractures (distraction, minimal contact surface)
• Soft tissue interposition: Muscle, periosteum trapped in fracture site
• Smoking: Strong association [13]
• Infection: In surgical cases
• Inadequate fixation: In surgical cases (too few screws, short plate)
• Distraction: Hanging cast with excessive weight
• Patient factors: Diabetes, malnutrition, NSAIDs (controversial)

Classification:

• Hypertrophic non-union ("Elephant's foot"): Abundant callus but no bridging - biological activity present, mechanical instability
• Atrophic non-union: No callus, sclerotic ends - biological inactivity, requires bone graft

Clinical Presentation:

• Persistent pain with use
• Abnormal mobility at fracture site
• Inability to use arm functionally

Investigation:

• X-ray: Persistent fracture line, no bridging callus, sclerotic bone ends
• CT: Assess for bridging bone, degree of gap

Management:

• Surgical fixation:
  • Compression plating: 4.5mm LCP, absolute stability
  • Bone graft: Autograft (iliac crest) for atrophic non-union or gap > 5mm
  • Hypertrophic non-union may not require graft (just stable fixation)
  • Remove fibrous tissue, freshen bone ends
• Post-operative: Immobilize 2 weeks, then progressive ROM
• Outcomes: 90-95% union after surgical fixation with bone graft [12]

2. Malunion

Definition: Fracture healed in unacceptable alignment

Incidence: 15-20% of conservatively managed fractures, usually asymptomatic [11]

Deformity:

• Varus angulation: Most common (adduction forces)
• Shortening: Cosmetic concern, rarely functional
• Rotation: May affect hand/elbow function

Functional Impact:

• Shoulder ball-and-socket joint compensates well for angulation
• Most malunions are cosmetic only with preserved function [11]
• Rarely, severe malunion causes functional limitation

Management:

• Observation: If asymptomatic and functionally acceptable
• Corrective osteotomy: Rarely needed; consider if significant functional impairment or patient dissatisfaction
  • Cut bone, realign, plate fixation
  • Indications: > 30° varus, > 20° rotational deformity with functional loss

3. Shoulder Stiffness

Incidence: 10-20% (conservative or surgical)

Risk Factors:

• Prolonged immobilization
• Inadequate physiotherapy
• Antegrade IM nail (rotator cuff violation) [6,7]
• Patient age (elderly less compliant with exercises)

Prevention:

• Early mobilization: Pendulum exercises from week 1-2
• Physiotherapy: Supervised ROM exercises
• Avoid prolonged immobilization: Transition to functional brace early

Management:

• Physiotherapy: Intensive supervised therapy, capsular stretching
• NSAIDs: Short course for pain/inflammation
• Manipulation under anesthesia: If severe stiffness persists > 6 months
• Arthroscopic capsular release: Refractory cases

4. Elbow Stiffness

Incidence: 5-10%

Risk Factors:

• Prolonged immobilization
• Retrograde IM nail (entry through olecranon fossa)
• Heterotopic ossification (rare)

Prevention: Early elbow ROM exercises (week 1-2)

Management: Physiotherapy, dynamic splinting, rarely surgical release

5. Heterotopic Ossification (Rare)

Incidence: less than 5%, higher with IM nailing

Presentation: Bone formation in soft tissues around fracture site, may limit ROM

Management: Observation, NSAIDs (Indomethacin), surgical excision if severe (after maturation at 12-18 months)

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10. Prognosis and Outcomes

Functional Outcomes

Conservative Management [3,4,5]:

• Union Rate: 90-95%
• Time to Union: 8-12 weeks (clinical), 12-16 weeks (radiological maturity)
• Shoulder ROM: 95-100% of contralateral side
• Elbow ROM: 95-100% of contralateral side
• Patient Satisfaction: High (> 90%)
• Return to Work: 12-16 weeks (sedentary), 16-24 weeks (manual labor)

Surgical Management [6,7]:

• Union Rate: 95-98% (plate), 85-90% (nail)
• Time to Union: 12-16 weeks (plate), 16-20 weeks (nail)
• Shoulder ROM: 90-95% (plate), 70-80% (antegrade nail - cuff morbidity)
• Complications: Higher infection risk (1-3%), iatrogenic nerve injury (3-5%)

Prognostic Factors

Good Prognosis:

• Simple fracture pattern (AO Type A)
• Acceptable alignment
• Young patient
• Non-smoker
• Good compliance with bracing/physiotherapy
• Early mobilization

Poor Prognosis:

• Severe comminution (AO Type C3)
• Transverse pattern with distraction
• Smoker [13]
• Open fracture (infection risk)
• Polytrauma
• Non-compliance

Return to Activities

Activities of Daily Living: 8-12 weeks Driving: 8-12 weeks (when can control steering wheel) Light Work: 12 weeks Heavy Manual Labor: 16-24 weeks Contact Sports: 20-24 weeks (with radiological confirmation of solid union)

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11. Evidence & Guidelines

Landmark Studies

Sarmiento et al. (2000) - Functional Bracing [5]

• Design: Prospective case series, 922 patients
• Intervention: Functional bracing protocol
• Results:
  • 98% union rate
  • 87% excellent or satisfactory functional outcome
  • Minimal residual disability
• Conclusion: Functional bracing is effective treatment for humeral shaft fractures; rigid immobilization unnecessary
• Impact: Established functional bracing as gold standard for conservative management

Randomized Controlled Trials: Surgery vs Conservative

Multiple RCTs have compared surgical fixation (plate or nail) to functional bracing:

• Findings: No significant difference in functional outcomes (DASH scores, shoulder/elbow ROM) at 12 months between surgery and bracing [3,4]
• Surgery: Faster early return to function, higher patient satisfaction in first 6 weeks
• Conservative: Equal or superior outcomes at 1 year, lower complication rate (no surgical site infection, lower iatrogenic nerve injury)
• Conclusion: Conservative management remains appropriate first-line treatment for isolated closed fractures with acceptable alignment

Non-Union Risk Factors

Oliver et al. (2021) - Factors associated with humeral shaft non-union [13]:

• Smoking: Strongest modifiable risk factor (OR 4.2)
• Transverse fracture pattern: OR 3.1
• Distraction: From hanging cast or inadequate reduction

Radial Nerve Palsy Prognosis

Bumbasirevic et al. (2016) - Radial nerve palsy review [10]:

• 90% spontaneous recovery in closed fractures with primary palsy
• Median recovery time: 3-4 months (range 6 weeks to 6 months)
• Exploration indicated if no recovery by 3-4 months or if secondary palsy
• EMG/NCS at 6-8 weeks helpful for prognosis

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12. Patient Explanation

What is a humeral shaft fracture?

You have broken the main bone in your upper arm (the humerus). This bone runs from your shoulder to your elbow. Fortunately, this bone heals very well without surgery in most cases.

Why no surgery?

Your arm bone is different from your leg bones - you don't walk on it, so it doesn't need to be perfectly straight to work well. Your shoulder joint is a ball-and-socket (like your hip), which means it compensates beautifully for small angles in the bone. Studies show that using a brace gives the same long-term result as surgery, but without the risks of surgery (infection, nerve damage from the operation).

The treatment plan - The brace

We will treat your fracture with a functional brace. This might seem strange because the bone isn't held completely rigid, but here's why it works:

• The brace squeezes the muscles around your arm
• These muscles act like a natural splint
• The bone is allowed to move just a tiny bit, which actually helps it heal (it forms a big ball of healing bone called "callus")
• You can move your shoulder and elbow, which prevents stiffness

The first 2 weeks - Hanging cast

For the first 1-2 weeks, we'll put your arm in a plaster or splint that hangs from your shoulder. The weight of the plaster helps pull the bone straight. Important: you must let your arm hang down - don't rest your elbow on chair arms or tables, as this pushes the bone up and creates a bend.

You'll need to sleep sitting up (in a recliner or propped up with lots of pillows). If you lie flat, gravity doesn't work, and the bone can become painful.

Weeks 2-12 - The functional brace

After 2 weeks, we'll transition you to a plastic brace that wraps around your upper arm. You'll wear this 24 hours a day (you can take it off briefly for washing, but put it straight back on). The brace needs to be snug - tighten it each day as the swelling goes down.

The nerve (if you have wrist drop)

The nerve to your wrist and fingers (the radial nerve) wraps around the bone like a ribbon on a pole. When the bone breaks, the nerve can get bruised or stretched. The good news: 90% of nerve injuries recover completely - the nerve just needs time to heal.

Think of the nerve like a phone cable that's been kinked - it needs to "grow back" slowly. Nerves grow at 1mm per day, which means it might take 3-4 months before your wrist lifts up again. We'll give you a splint to keep your wrist up in the meantime, so your hand doesn't get stiff.

What to expect - Timeline

• Weeks 0-2: Pain, swelling, arm in hanging cast
• Weeks 2-6: Transition to brace, start shoulder exercises, pain improving
• Weeks 6-12: Continued brace, bone healing visible on X-ray, increasing use of arm
• Week 12: Likely healed enough to start weaning off brace
• Month 4-6: Back to normal activities

Warning signs - When to contact us

• Wrist drop that develops AFTER we've manipulated the bone (nerve might be trapped)
• Increasing pain in your arm (should be improving)
• Fingers going cold, pale, or numb (circulation problem)
• Brace rubbing causing skin breakdown

Long-term outlook

Excellent. Over 90% of patients heal completely with full use of their arm. The bone might look a bit lumpy on X-rays (that's the healing callus), and it might be slightly bent, but this doesn't affect function. Your shoulder compensates beautifully.

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13. Examination Focus (Viva Vault)

Question 1: What are the absolute indications for surgery in a humeral shaft fracture?

Model Answer: The absolute indications for surgical fixation are:

1. Open fracture (all grades - requires debridement, fracture stabilization is part of management)
2. Vascular injury requiring arterial repair (brachial artery laceration)
3. Floating elbow - ipsilateral humerus and forearm fractures create unstable mechanical linkage requiring humerus fixation
4. Polytrauma - patient requires upper limbs for mobility aids, transfers, crutches
5. Bilateral humeral shaft fractures - patient needs at least one functional arm
6. Pathological fracture - underlying malignancy or bone lesion
7. Segmental fracture - mechanically unstable, difficult to brace effectively

Relative indications include failure of conservative management (non-union, loss of reduction), and radial nerve palsy developing after closed reduction (secondary palsy).

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Question 2: Describe the management of a radial nerve palsy presenting AFTER manipulation of a humeral shaft fracture.

Model Answer: A radial nerve palsy developing after closed reduction is a secondary palsy and represents a different scenario from a primary palsy present at initial presentation.

Mechanism: The nerve has likely been entrapped between fracture fragments during the manipulation, or has been placed under excessive traction.

Management:

• High suspicion for nerve entrapment - this is NOT a simple neuropraxia
• Urgent surgical exploration (within 1-2 weeks) is strongly considered
• Intraoperative findings:
  • Identify radial nerve
  • Free entrapped nerve from fracture fragments
  • Remove any bone spikes or fragments compressing nerve
  • Consider neurolysis if nerve appears damaged
  • If nerve is transected: primary repair or tag ends for delayed nerve graft
• Fracture fixation: Stabilize fracture (usually plating via posterior approach to visualize nerve)
• Post-operative: Wrist extension splint, physiotherapy

Contrast with primary palsy: Primary palsy (present at presentation) in a closed fracture has 90% spontaneous recovery rate and is managed expectantly with observation. Secondary palsy has much lower spontaneous recovery rate and requires active intervention.

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Question 3: Why is intramedullary nailing less preferred than plating for humeral shaft fractures?

Model Answer: Intramedullary nailing is less preferred than compression plating for several evidence-based reasons:

1. Rotator Cuff Morbidity (Antegrade Nailing):

• Entry point is through the greater tuberosity or just medial to it
• Violates rotator cuff insertion (supraspinatus primarily)
• Results in persistent shoulder pain and stiffness in 20-30% of patients
• Significant functional limitation in overhead activities

2. Lower Union Rates:

• IM nailing: 85-90% union rate
• Compression plating: 95-98% union rate
• Nails provide relative stability (load-sharing), plates provide absolute stability (compression)

3. Longer Time to Union:

• IM nailing: 16-20 weeks average
• Plating: 12-16 weeks average

4. Malrotation Risk:

• Difficult to control rotation with intramedullary fixation
• Rotation clinically assessed intraoperatively but can be inaccurate

5. Elbow Complications (Retrograde Nailing):

• Entry through olecranon fossa
• Risk of elbow stiffness, heterotopic ossification
• Rarely performed

When IS nailing indicated?

• Pathological fractures: Nail protects entire bone (metastatic disease can affect multiple sites)
• Bilateral humeral fractures: Faster surgery, allows simultaneous bilateral fixation
• Segmental fractures: Load-sharing device appropriate

Current Consensus: Compression plating is the gold standard for surgical fixation of humeral shaft fractures. IM nailing reserved for specific indications where its advantages (load-sharing, protection of entire bone) outweigh disadvantages.

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Question 4: What is the Holstein-Lewis fracture and why is it significant?

Model Answer: Definition: A Holstein-Lewis fracture is a spiral fracture of the distal third of the humeral shaft.

Eponym: Named after Holstein and Lewis who described the high association with radial nerve injury in 1963.

Anatomical Significance: The radial nerve is particularly vulnerable in distal third fractures because:

1. The nerve winds around the posterior humerus in the spiral groove
2. Approximately 10cm proximal to the lateral epicondyle, the nerve pierces the lateral intermuscular septum (LIMS) to enter the anterior compartment
3. This creates a tethering point where the nerve is fixed
4. In a distal third spiral fracture:
   • The distal fragment displaces proximally (pulled by biceps, brachialis, triceps)
   • The nerve is trapped between the fracture fragments OR
   • The nerve is pulled taut against the lateral intermuscular septum OR
   • A bone spike lacerates the nerve

Incidence of Radial Nerve Injury: Up to 20% (compared to 11-13% overall for all humeral shaft fractures)

Management:

• If nerve intact at presentation: Conservative management as per standard protocol (functional bracing), expect normal union
• If radial nerve palsy at presentation (primary palsy): Expectant management with observation (90% spontaneous recovery), dynamic wrist splint, EMG at 6-8 weeks if no recovery
• If radial nerve palsy develops after manipulation (secondary palsy): Consider urgent exploration
• If surgical fixation required (for other indications): Use posterior approach to directly visualize and protect nerve during reduction and fixation

Key Point: The Holstein-Lewis fracture is NOT an indication for surgery by itself (if closed, neurovascularly intact or with primary palsy, and acceptable alignment). Conservative management is still appropriate and successful.

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Question 5: Outline the Sarmiento functional bracing protocol and explain the principle behind it.

Model Answer:

Principle: The Sarmiento functional bracing protocol, developed in the 1970s, is based on the concept that controlled micromotion promotes fracture healing through abundant callus formation, and that rigid immobilization is unnecessary for humeral shaft fractures.

Mechanism of Action:

• The brace provides hydrostatic compression of the soft tissue envelope (muscles, fascia)
• This soft tissue acts as a "biological splint" stabilizing the underlying bone cylinder
• Gravity acts as an aligning force (dependent arm)
• Early shoulder and elbow motion is permitted, preventing joint stiffness
• Micromotion at the fracture site stimulates hypertrophic callus formation

Protocol:

Phase 1 (Weeks 0-2) - Hanging Cast/U-Slab:

• Coaptation splint or hanging cast from shoulder to elbow
• Weight of cast provides traction to reduce shortening
• Arm MUST hang freely (no elbow support)
• Patient sleeps semi-recumbent (30-45° minimum)
• Pendulum shoulder exercises, active elbow/wrist/hand ROM
• Weekly X-rays to monitor alignment

Phase 2 (Weeks 2-12) - Functional Brace:

• Transition to custom or pre-fabricated thermoplastic shell brace
• Extends from 2cm below axilla to 2cm above elbow
• Worn 24 hours/day (remove only for hygiene)
• Tightened circumferentially (patient adjusts as swelling decreases)
• Full shoulder and elbow ROM encouraged
• No lifting > 5kg
• X-rays: weekly x3, then bi-weekly until union

Phase 3 (Weeks 12+) - Rehabilitation:

• Gradual brace weaning over 2-4 weeks
• Progressive strengthening
• Return to functional activities

Acceptable Deformity: Due to shoulder ball-and-socket compensation:

• 20° anterior/posterior angulation
• 30° varus/valgus angulation
• 3cm shortening
• 15-20° rotation

Outcomes:

• Union rate: 90-95%
• Time to union: 8-12 weeks clinically, 12-16 weeks radiologically
• Functional outcome: Excellent shoulder and elbow ROM (95-100% of contralateral)
• Patient satisfaction: High (> 90%)

Success Factors:

• Patient compliance (critical - must wear brace, avoid lifting, let arm hang)
• Appropriate fracture pattern (not severely comminuted Type C3)
• Acceptable initial alignment or reducible

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14. References

1. Tytherleigh-Strong G, Walls N, McQueen MM. The epidemiology of humeral shaft fractures. J Bone Joint Surg Br. 1998;80(2):249-253. doi:10.1302/0301-620X.80B2.8113

2. Ekholm R, Adami J, Tidermark J, Hansson K, Törnkvist H, Ponzer S. Fractures of the shaft of the humerus: an epidemiological study of 401 fractures. J Bone Joint Surg Br. 2006;88(11):1469-1473. doi:10.1302/0301-620X.88B11.17634

3. Matsunaga FT, Tamaoki MJ, Matsumoto MH, Netto NA, Faloppa F, Belloti JC. Treatment of humeral shaft fractures: minimally invasive osteosynthesis with a bridge plate versus conservative treatment with a functional brace. Bone Joint J. 2017;99-B(7):954-963. doi:10.1302/0301-620X.99B7.BJJ-2016-1208.R1

4. Rangan A, Handoll H, Brealey S, et al. Surgical vs nonsurgical treatment of adults with displaced fractures of the proximal humerus: the PROFHER randomized clinical trial. JAMA. 2015;313(10):1037-1047. doi:10.1001/jama.2015.1629

5. Sarmiento A, Zagorski JB, Zych GA, Latta LL, Capps CA. Functional bracing for the treatment of fractures of the humeral diaphysis. J Bone Joint Surg Am. 2000;82(4):478-486. doi:10.2106/00004623-200004000-00003

6. Changulani M, Jain UK, Keswani T. Comparison of the use of the humerus intramedullary nail and dynamic compression plate for the management of diaphyseal fractures of the humerus: a randomised controlled study. Int Orthop. 2007;31(3):391-395. doi:10.1007/s00264-006-0200-1

7. Bhandari M, Devereaux PJ, McKee MD, Schemitsch EH. Compression plating versus intramedullary nailing of humeral shaft fractures - a meta-analysis. Acta Orthop. 2006;77(2):279-284. doi:10.1080/17453670610046046

8. Bumbasirevic M, Palibrk T, Lesic A, Atkinson HD. Radial nerve palsy. EFORT Open Rev. 2016;1(8):286-294. doi:10.1302/2058-5241.1.000028

9. Shao YC, Harwood P, Grotz MR, Limb D, Giannoudis PV. Radial nerve palsy associated with fractures of the shaft of the humerus: a systematic review. J Bone Joint Surg Br. 2005;87(12):1647-1652. doi:10.1302/0301-620X.87B12.16132

10. Bumbasirevic M, Palibrk T, Lesic A, Atkinson HD. Radial nerve palsy. EFORT Open Rev. 2016;1(8):286-294. doi:10.1302/2058-5241.1.000028

11. Klenerman L. Fractures of the shaft of the humerus. J Bone Joint Surg Br. 1966;48(1):105-111.

12. Mayr E, Rüter A, Kohler G. The results of internal fixation for the treatment of humeral shaft pseudarthrosis. Arch Orthop Trauma Surg. 2000;120(3-4):168-172. doi:10.1007/s004020050031

13. Oliver WM, Smith TJ, Nicholson JA, et al. Factors associated with humeral shaft nonunion: a multicentre observational cohort study of 571 patients. Injury. 2021;52(5):1112-1118. doi:10.1016/j.injury.2021.02.045

14. Hung LK, Chow YY, Leung PC. Floating elbow in children. J Bone Joint Surg Br. 1996;78(5):847-850.

15. Ekholm R, Ponzer S, Törnkvist H, Adami J, Tidermark J. The Holstein-Lewis humeral shaft fracture: aspects of radial nerve injury, primary treatment, and outcome. J Orthop Trauma. 2008;22(10):693-697. doi:10.1097/BOT.0b013e31818915bf

16. Whitson RO. Relation of the radial nerve to the shaft of the humerus. J Bone Joint Surg Am. 1954;36(1):85-88.

17. Gainor BJ, Olson S. Combined entrapment of the median and anterior interosseous nerves in the proximal forearm. J Hand Surg Am. 1986;11(1):93-96. doi:10.1016/s0363-5023(86)80117-7

18. Mahabier KC, Vogels LM, Punt BJ, Roukema GR, Patka P, Van Lieshout EM. Reliability and reproducibility of the OTA/AO classification for humeral shaft fractures. J Orthop Trauma. 2017;31(12):e381-e385. doi:10.1097/BOT.0000000000000952

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