Supracondylar Fractures (Adult)

Dual Column Concept

The distal humerus consists of two columns forming a triangular architecture:

Medial Column

• Extends from supracondylar ridge to medial epicondyle
• Contains the trochlea (articulates with ulna)
• Common flexor origin attachment
• Ulnar nerve courses posteriorly

Lateral Column

• Extends from supracondylar ridge to lateral epicondyle
• Contains the capitellum (articulates with radius)
• Common extensor origin attachment
• More robust than medial column

Supracondylar Region

The supracondylar area is the weakest point due to transition from cylindrical diaphysis to flat metaphysis, thin cortical bone bridging the columns, olecranon and coronoid fossae creating stress risers, and the supracondylar ridges which mark the proximal extent.

Load Transmission

Forces across the elbow are transmitted through the dual column system:

• 60% through radiocapitellar joint (lateral column)
• 40% through ulnotrochlear joint (medial column)

Fracture Mechanics

Extension Type (95%)

• Mechanism: Axial load with elbow in extension or direct blow
• Force vector: Anterior-to-posterior
• Displacement: Distal fragment displaces posteriorly
• Tension side: Anterior cortex (where plate ideally placed)

Flexion Type (5%)

• Mechanism: Direct blow to posterior elbow or fall on flexed elbow
• Force vector: Posterior-to-anterior
• Displacement: Distal fragment displaces anteriorly
• Tension side: Posterior cortex

Stability Considerations

Stability requires restoration of both columns (single column fixation is insufficient), and rigid fixation is needed for early ROM.

At-Risk Structures

Ulnar Nerve

• Runs in cubital tunnel behind medial epicondyle
• At risk with:
  • Medial column fracture displacement
  • Medial surgical approach
  • Plate placement
• Routine transposition is debated, and the evidence does not support it as protective. In 69 bicolumnar fractures (OTA 13A and 13C) with no pre-operative deficit, ulnar nerve dysfunction was present in 10.1% immediately after surgery and 16% at final follow-up, and no treatment factor - transposition included - was associated with the risk; the authors state plainly that transposition was not protective, and that a retrospective design probably underestimates the true rate. A later review reported late ulnar neuropathy in 38% after this operation, again with no significant difference between in-situ release and anterior transposition.
• What follows for practice and for consent. Identify and protect the nerve in every case, decide on transposition by what the plate actually does to the cubital tunnel rather than by routine, and warn the patient before surgery that some ulnar symptoms are common - this is one of the few complications where the honest quoted figure is well into double digits, and a patient told nothing will reasonably attribute it to a technical error.

Radial Nerve

• Pierces lateral intermuscular septum 10cm above lateral epicondyle
• At risk with:
  • Proximal fracture extension
  • Anterolateral approach

Median Nerve and Brachial Artery

• Run anteriorly in antecubital fossa
• Less commonly injured than in pediatric fractures
• Risk with anterior spike of proximal fragment

Vascular Considerations

Brachial artery injury is less common than in pediatric fractures. Collateral circulation is usually adequate, and a pulseless but perfused limb may be observed.

Adult supracondylar fractures are classified under AO/OTA 13-A (extraarticular distal humerus).

Type 13-A1: Simple Extraarticular

Single fracture line with transverse or short oblique pattern. Subtypes include A1.1 (apophyseal avulsion), A1.2 (simple metaphyseal), and A1.3 (simple metaphyseal with instability).

Type 13-A2: Metaphyseal Wedge

Wedge fragment in metaphysis with more comminution than A1. Subtypes include A2.1 (intact wedge), A2.2 (fragmented wedge), and A2.3 (fragmented wedge with instability).

Type 13-A3: Complex Metaphyseal

Significant comminution with no simple fracture pattern. Subtypes include A3.1 (spiroid pattern), A3.2 (irregular pattern), and A3.3 (irregular with bone loss).

By Displacement Direction

By Fracture Pattern

By Bone Quality

Critical consideration: Good bone allows standard plate fixation. Osteoporotic bone requires locking plates with possible cement augmentation. Severely osteoporotic bone warrants consideration of primary TEA.

Inspection

• Swelling: Significant periarticular swelling
• Deformity: S-shaped (extension) or reverse S-shaped (flexion)
• Skin: Open wounds, tenting, blisters
• Ecchymosis: Anterior (extension), posterior (flexion)

Palpation

• Assess column integrity
• Point tenderness over fracture site
• Crepitus with gentle movement
• Triangle of Hueter: Normal in supracondylar (extraarticular)

Range of Motion

• Do not force examination in acute setting
• Document pre-injury ROM if possible
• Assess elbow and forearm rotation

Special Tests

Examination must be systematic and documented.

Nerve Examination

Ulnar Nerve (Most Commonly Affected)

• Motor: First dorsal interosseous, finger abduction
• Sensory: Small finger and ulnar half ring finger
• Test: Cross fingers, card test
• Document pre-operative status - critical for medicolegal

Radial Nerve

• Motor: Wrist and finger extension
• Sensory: First dorsal web space
• Test: Wrist extension against resistance

Median Nerve

• Motor: Thumb opposition, index finger flexion
• Sensory: Palmar thumb, index, middle fingers
• Test: OK sign, FPL function

Anterior Interosseous Nerve (AIN)

• Motor: FPL, FDP to index, pronator quadratus
• Test: OK sign (can't make circle)

Vascular Assessment

• Radial and ulnar pulses
• Capillary refill
• Compare to contralateral side
• Doppler if pulses not palpable

Standard Views

AP View

• Assess column integrity
• Measure fracture angle
• Evaluate medial/lateral displacement
• Look for articular involvement (would classify as intercondylar)

Lateral View

• Confirm extraarticular nature
• Extension type: Posterior displacement of distal fragment
• Flexion type: Anterior displacement of distal fragment
• S-shaped deformity (extension type)
• Assess coronoid and olecranon fossa involvement

Radiographic Signs

Full-Length Humerus

Full-length humerus views are required for plate length planning, to exclude proximal extension, and to evaluate for pathologic fracture.

Indications

• Unclear fracture pattern on plain films
• Assessment of comminution degree
• Confirm extraarticular vs intercondylar
• Preoperative planning for complex patterns

Protocol

• Thin-cut axial images (1-2mm)
• 3D reconstructions essential for surgical planning
• Coronal and sagittal reformats
• Include full distal humerus

Key Assessments

MRI

Limited role in acute fracture management but may assess:

• Ligament integrity
• Soft tissue interposition
• Occult pathology

DEXA Scan

Consider in:

• Low-energy fractures in elderly
• Planning for fragility fracture pathway
• Informing fixation strategy (locking plates, cement)

Angiography

Indications:

• Hard signs of vascular injury (pulseless cold limb)
• Expanding hematoma
• Bruit/thrill
• Active hemorrhage

Nerve Conduction Studies

NCS are not typically performed acutely but may be useful for documenting pre-existing neuropathy, evaluating post-operative nerve dysfunction, and medicolegal documentation.

Non-Operative Indications

Non-operative management is appropriate for minimally displaced fractures (under 5mm), stable patterns on stress views, non-ambulatory patients with minimal functional demands, and patients with medical comorbidities precluding surgery or patient preference after informed consent.

Operative Indications (Most Cases)

Surgery is indicated for displacement over 5mm, any angulation, unstable patterns, polytrauma requiring mobilization, open fractures, and cases with vascular injury requiring repair.

Week 0-2

Long arm splint in 90° flexion with ice and elevation. Begin hand and shoulder exercises.

Week 2-4

Convert to hinged brace. Begin gentle ROM within brace targeting full extension to 90° flexion range.

Week 4-6

Increase ROM progressively, begin strengthening, and wean from brace.

Week 6 Onwards

Full ROM exercises, progressive strengthening, and return to activities.

Expected Outcomes

Non-operative management often results in poor ROM recovery with high rates of stiffness. This approach is reserved for truly stable patterns or poor surgical candidates.

Posterior Approach (Most Common)

Indications

• Complex fracture patterns
• Need for dual column access
• Olecranon osteotomy planned

Technique

1. Position: Lateral decubitus or prone
2. Midline posterior incision
3. Full-thickness flaps
4. Identify and protect ulnar nerve
5. Access columns via:
   • Triceps-splitting
   • Triceps-reflecting (Bryan-Morrey)
   • Olecranon osteotomy

Advantages

• Excellent exposure
• Allows dual plating
• Can extend proximally/distally

Disadvantages

• Extensile dissection
• Triceps dysfunction risk
• Higher stiffness rates

Lateral Approach (Kocher)

Indications

• Simple lateral column fractures
• Less comminuted patterns

Technique

1. Lateral skin incision
2. Interval: anconeus and ECU
3. Protect radial nerve
4. Access lateral column

Medial Approach

Indications

• Isolated medial column fractures
• Ulnar nerve exploration needed

Technique

The medial approach involves a medial skin incision, identification of the ulnar nerve first, protection or transposition of the nerve, then access to the medial column.

Dual Plating (Gold Standard)

Plate Configuration

Say this carefully in a viva. The biomechanical edge belongs to parallel plating, but it is cadaveric, paired-specimen, osteoporotic AO C2 bone, and both constructs allowed early mobilisation - which is the outcome that actually matters. No clinical trial has shown one configuration to be superior in patients. The defensible position is that the configuration matters less than the principles below, and that the surgeon should use whichever lets them get maximum screw purchase in the distal fragments.

Principles

• Minimum 6 cortices proximal to fracture in each column
• Maximum screw density in distal fragments
• Locking screws in osteoporotic bone
• Anatomic plates match distal humerus contour

Screw Placement

Technical Pearls

1. Reduce articular surface first (if any involvement)
2. Provisional K-wire fixation
3. Plate one column, reduce other, plate second
4. Check impingement through ROM
5. Intraoperative imaging confirms position

Indications

• Complex fracture patterns
• Need for articular visualization (if concern for extension)
• TEA approach

Technique

Osteotomy Types

Steps

1. Mark osteotomy at bare area (non-articular)
2. Pre-drill screw holes before osteotomy
3. Score with saw, complete with osteotome
4. Elevate olecranon with triceps attached
5. Excellent articular and column exposure

Fixation of Osteotomy

Complications

• Non-union (5-10%)
• Hardware prominence
• Need for removal

Osteoporotic Bone

Challenges

• Poor screw purchase
• Comminution
• Implant cutout risk

Solutions

High-Energy Trauma

Considerations

• Associated injuries
• Soft tissue status
• Damage control principles

Staged Approach

1. Temporary spanning external fixator
2. Soft tissue recovery (7-14 days)
3. Definitive ORIF

Open Fractures

Elderly Low-Demand

Consider primary Total Elbow Arthroplasty (TEA) if:

• Age over 65-70 with comminuted fracture
• Severe osteoporosis
• Low functional demands
• Rheumatoid arthritis
• Pre-existing arthritis

Neurovascular Injury

Ulnar Nerve (Most Common)

• Incidence: 15-20% (neuropraxia)
• Causes: Initial injury, surgical manipulation, hardware
• Management: Observation 3 months, then exploration if no recovery

Radial Nerve

• Incidence: 5-10%
• Causes: Proximal fracture extension, lateral approach
• Management: As above

Vascular Injury

• Less common than pediatric
• Brachial artery at risk anteriorly
• May require vascular repair

Infection

Wound Complications

Wound issues include skin necrosis (especially with posterior approach), dehiscence, and hematoma. Risk is higher with diabetes, smoking, and anticoagulation.

Stiffness (Most Common)

Risk Factors

• Prolonged immobilization
• Heterotopic ossification
• Intra-articular adhesions
• Complex fracture pattern
• Poor compliance with rehab

Prevention

• Stable fixation (dual plating)
• Early ROM (within 2 weeks)
• Indomethacin prophylaxis (for HO)
• Aggressive physiotherapy

Management

Heterotopic Ossification

• Incidence: 5-25%
• Risk factors: Head injury, burns, delayed surgery
• Prevention: Indomethacin 75mg daily x 6 weeks OR single-dose radiation
• Treatment: Excision if mature (12-18 months) and symptomatic

Malunion

Nonunion

Nonunion occurs in 2-5% of cases. Risk factors include smoking, diabetes, infection, and inadequate fixation. Management involves revision ORIF with bone graft or consideration of TEA.

Hardware Failure

Hardware Prominence

• Common posteriorly
• May require removal after union
• Use low-profile plates when possible

Ulnar Nerve Irritation

• From medial plate or screws
• May require transposition
• Consider anterior transposition at index procedure

Implant Removal