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OR 2.4 - Fracture of Shaft of Humerus & Intercondylar Fracture Humerus with Neurovascular Deficit

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ANATOMY OF HUMERUS

Structure

• Typical long bone of the arm
• Upper half: roughly cylindrical; middle: triangular; lower half: flattens in the antero-posterior direction
• Divided into three longitudinal surfaces: anterolateral, anteromedial, and posterior

Key Landmarks

Distal Humerus

• Flattened in anteroposterior plane
• Bears: 2 condyles, 2 epicondyles, 3 fossae
  • Fossae anteriorly: radial fossa, coronoid fossa
  • Fossa posteriorly: olecranon fossa

Articulations

• Proximally: Head articulates with glenoid of scapula - shoulder joint (ball and socket)
• Distally: Articulates with olecranon (ulna) and radius - elbow joint (hinge type)

Clinical Relevance of Muscle Envelope

• (a) Low incidence of compound/open fractures
• (b) Early union due to rich periosteal blood supply
• (c) Some degree of malunion masked by thick muscle cover

Neurovascular Structures at Risk

• Axillary nerve - shoulder region
• Radial nerve - spiral groove (most commonly injured, 10-12% of closed humeral shaft fractures)
• Ulnar nerve - medial epicondyle region
• Brachial artery and its branches

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PART A: FRACTURE OF SHAFT OF HUMERUS

Epidemiology

• 1-2% of all fractures; 13-14% of all humerus fractures
• Bimodal distribution: Young males (high-energy) + elderly females (low-energy falls)
• Most common cause: ground-level fall, followed by road traffic accidents

Mechanism of Injury

AO/OTA Classification

• Type A - Simple (transverse, oblique, spiral)
• Type B - Wedge (spiral wedge, bending wedge, fragmented wedge)
• Type C - Complex/comminuted (spiral, segmental, irregular)

Displacement Patterns (Based on Level)

• Fracture above deltoid insertion (proximal third): Proximal fragment - adducted by pectoralis major; distal fragment - abducted by deltoid
• Fracture below deltoid insertion (middle/distal third): Proximal fragment - abducted by deltoid; distal fragment - pulled proximally
• Holstein-Lewis fracture: Spiral fracture of distal third - associated with radial nerve neuropraxia

Clinical Features

• Pain + swelling + deformity of upper arm
• Patient supports injured arm with opposite hand
• Visible/palpable crepitus (avoid deliberate elicitation)
• Neurovascular exam is mandatory:
  • Check wrist/finger dorsiflexion (radial nerve)
  • Sensory loss - dorsoradial hand and dorsal aspect of first 3.5 digits
  • Radial and ulnar pulse at wrist

Investigations

1. X-ray - AP + lateral humerus (must include shoulder and elbow joints)
2. CT scan - for complex/intra-articular fractures
3. MRI/nerve conduction studies - for nerve injury assessment
4. Doppler/angiography - if vascular injury suspected

Management

Conservative (First-line for most closed fractures)

1. Collar and cuff sling - weight of arm provides traction and aligns fracture
2. U-slab plaster - from axilla, around elbow, up outer aspect and over shoulder, held with circumferential bandage
3. Functional brace (Sarmiento) - applied at 1-2 weeks once swelling subsides; allows shoulder and elbow motion; most preferred conservative method
4. Hanging cast - gravity traction; patient must sleep semi-upright

Operative Indications

• Inability to maintain reduction by closed means
• Multiple injuries / polytrauma
• Bilateral fractures
• Floating elbow (ipsilateral forearm fractures)
• Intra-articular fracture extension
• Progressive nerve palsy or palsy after closed manipulation
• Significant vascular injury
• Open fractures

• Segmental fractures
• Pathologic fractures
• Obesity / large breasted (cannot use brace)
• Noncompliant patients

Operative Methods

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PART B: INTERCONDYLAR FRACTURE OF HUMERUS

Mechanism of Injury

• Direct trauma to the elbow - olecranon driven like a wedge against the articular surface of distal humerus, splitting the condyles apart
• Seen in adults aged 50-70 years
• High-energy injury in young; low-energy fall in elderly

Riseborough & Radin Classification (most used)

Fracture Pattern

• T-shaped or Y-shaped fracture on X-ray
• Variable separation of condyles from each other and from the proximal humeral shaft
• Fracture line extends to the articular surface

Clinical Features

• Pain, swelling, deformity at elbow
• Tenderness over both epicondyles
• Elbow held in slight flexion
• "Bag of bones" feel - due to comminution
• Neurovascular complications are less common than shaft fractures, but check for:
  • Ulnar nerve (medial epicondyle)
  • Median nerve
  • Brachial artery

Investigations

1. X-ray AP + lateral - T/Y fracture pattern, condylar separation
2. CT scan - mandatory for surgical planning; delineates comminution and articular involvement

Management

Conservative (Limited)

• Elderly patients unfit for surgery
• Non-displaced fractures (Type I)
• Medical comorbidities prohibiting anesthesia
• Method: collar-and-cuff + early mobilization ("bag of bones" technique in elderly)

Operative (Preferred)

• ORIF with dual plating - gold standard; medial and lateral column plating (parallel or 90-90 plating)
• Y-shaped plate on posterior surface of humerus
• Approach: Posterior approach with olecranon osteotomy (best exposure)
• Total elbow arthroplasty (TEA) in elderly with severe comminution

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PART C: NEUROVASCULAR DEFICIT - EMPHASIS

Radial Nerve Injury (Most Common in Shaft Fractures)

Anatomy of Risk

• Radial nerve runs in the spiral (radial) groove on the posterior humerus in its middle third
• Most vulnerable at the junction of middle and distal thirds
• Holstein-Lewis fracture (spiral distal third fracture) = classic association

Clinical Presentation

• Wrist drop - inability to dorsiflex wrist
• Inability to extend MCP joints (finger drop)
• Weakness of thumb extension/abduction
• Sensory loss: dorsoradial hand, dorsal aspect of first 3.5 digits (autonomous zone: first dorsal web space)

Management of Radial Nerve Palsy with Humeral Shaft Fracture

• Primary (closed fracture): Expectant/conservative - wait and watch; 70-80% of neuropraxia recoveries spontaneously in 3-4 months
• Explore immediately if:
  • Open fracture
  • Vascular injury requiring exploration
  • Palsy develops after closed manipulation
  • Progressive palsy
• Electromyography (EMG) and nerve conduction studies (NCS) at 6-8 weeks to assess recovery
• If no recovery by 3-6 months: surgical exploration and nerve repair

Brachial Artery Injury (Critical in Supracondylar Fractures in Children)

Clinical Assessment (5 Ps)

Volkmann's Ischemic Contracture (Complication of Untreated Ischemia)

• Due to brachial artery injury in supracondylar fractures - forearm muscle ischemia
• Results in: flexion contracture of wrist and fingers, claw hand
• Prevention: Urgent reduction + vascular repair; never ignore absent pulse with ischemic signs

Ulnar Nerve - Elbow Region

• At risk in intercondylar and medial epicondyle fractures
• Presents with: clawing of ring and little fingers, sensory loss over little finger and ulnar half of ring finger
• Weakness of intrinsic hand muscles (interossei, hypothenar, adductor pollicis)

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HIGH-YIELD EXAM POINTS

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