Monteggia Fracture-Dislocation

1. Clinical Overview

Summary

A Monteggia fracture-dislocation is a fracture of the proximal third of the ulna with an associated dislocation of the radial head at the proximal radioulnar joint (PRUJ). First described by Giovanni Battista Monteggia in 1814, this injury remains a notorious diagnostic trap for the unwary clinician: the ulna fracture is typically obvious on radiographs, but the radial head dislocation is frequently missed in 30-50% of acute cases, leading to disastrous chronic limitation of elbow flexion and forearm rotation. [1,2]

The radiocapitellar line is the diagnostic cornerstone: a line drawn through the longitudinal axis of the radial shaft MUST bisect the capitellum on all radiographic views, regardless of the degree of elbow flexion or extension. Failure of this line to pass through the capitellum indicates radial head dislocation. [3]

Treatment in adults is almost exclusively surgical (open reduction and internal fixation of the ulna) to restore anatomical length and alignment, which typically reduces the radial head by restoring the normal length-tension relationship of the interosseous membrane. In children, closed reduction is often successful. The injury carries significant morbidity if missed or inadequately treated, including chronic elbow instability, stiffness, and persistent radial head dislocation requiring complex reconstruction. [4,5]

Key Facts

• Mnemonic: MUGR (Monteggia Ulna, Galeazzi Radius). Monteggia affects the ulna with radial head dislocation; Galeazzi affects the radius with distal radioulnar joint disruption.
• Radiocapitellar Line: If the line misses the capitellum on any view, the radial head is dislocated.
• Nerve at Risk: Posterior Interosseous Nerve (PIN), which wraps around the radial neck and can be stretched, contused, or tethered during dislocation or reduction.
• Incidence: Accounts for 1-2% of all forearm fractures, with a bimodal distribution (children 4-10 years and adults 20-50 years).
• Mechanism: Most commonly falls on outstretched hand (FOOSH) with hyperpronation, or direct blow to the ulna ("nightstick" mechanism).

Clinical Pearls

"Every Ulna Fracture is a Monteggia until proven otherwise": If you see an isolated ulna shaft fracture ("nightstick fracture"), scrutinize the elbow radiographs. If the PRUJ is tender or the radiocapitellar line is not perfect, assume the radial head is dislocated until proven otherwise. Always obtain dedicated elbow films. [6]

"The Ulna Rules the Radius": The radius is tethered to the ulna by the interosseous membrane and annular ligament. If the ulna shortens or angulates, the radius MUST dislocate to accommodate the length mismatch. Anatomical restoration of ulna length and alignment pulls the radius back into place via ligamentotaxis. [7]

"Bado I is Commonest": Anterior dislocation of the radial head with anterior angulation of the ulna apex (extension type injury) accounts for approximately 70% of all Monteggia fractures and is most common in children. [8]

"Bado II is the Bad Actor": Posterior dislocation (Bado II) carries the highest risk of PIN injury (up to 20%), is associated with coronoid fractures (akin to terrible triad), and has the worst prognosis for functional recovery. [9,10]

---

2. Epidemiology

Demographics

• Incidence: 1-2% of all forearm fractures, 5-10% of pediatric forearm fractures. [11]
• Age Distribution: Bimodal
  • Pediatric Peak: 4-10 years (most common in this age group due to ligamentous laxity and mechanism of injury).
  • Adult Peak: 20-50 years (typically higher energy mechanisms).
• Gender: Slight male predominance (60-65%) due to occupational and recreational injury patterns. [12]
• Mechanism:
  • Hyperpronation: Fall on outstretched hand (FOOSH) with forced hyperpronation and elbow hyperextension. This is the classic mechanism for Bado Type I.
  • Direct Blow: "Nightstick" injury to the proximal ulna (raises defensive arm to block blow). Can result in Type I or Type II depending on elbow position.
  • Axial Load: High-energy trauma (motor vehicle collision, fall from height) with axial loading through the hand. Associated with Type IV and complex variants.

Historical Context

Giovanni Battista Monteggia, an Italian surgeon, first described this injury pattern in 1814 in two patients. The classification system most widely used today was developed by José Luis Bado in 1967, who expanded the injury description to include four distinct patterns based on the direction of radial head dislocation and ulnar fracture angulation. [13]

---

3. Pathophysiology

Anatomy

• Proximal Radioulnar Joint (PRUJ):
  • Articulation between the radial head and radial notch of the ulna.
  • Stabilized primarily by the annular ligament, which encircles the radial head and inserts on the anterior and posterior margins of the radial notch.
  • Secondary stabilizers include the quadrate ligament (stabilizes radial neck), lateral collateral ligament complex, and the interosseous membrane.
• Interosseous Membrane (IOM):
  • Fibrous connective tissue extending from the interosseous border of the radius to the interosseous border of the ulna.
  • The central band is the strongest and primary load-bearing structure.
  • Functions to transmit axial loads from radius to ulna (60% of axial load transmitted through radiocarpal joint passes through IOM to ulna).
  • Maintains the length-tension relationship between radius and ulna during pronation-supination.
• Posterior Interosseous Nerve (PIN):
  • Terminal branch of the radial nerve after it bifurcates into superficial (sensory) and deep (motor) branches.
  • Passes through the supinator muscle (between superficial and deep heads) approximately 4-6 cm distal to the radiocapitellar joint.
  • Wraps around the radial neck, making it vulnerable to traction injury during radial head dislocation.
  • Innervates: Extensor digitorum communis (EDC), extensor pollicis longus (EPL), extensor pollicis brevis (EPB), extensor indicis proprius (EIP), extensor carpi ulnaris (ECU), abductor pollicis longus (APL).
  • Clinical Pearl: Wrist extension is PRESERVED in PIN palsy (extensor carpi radialis longus/brevis innervated by radial nerve proper before PIN bifurcation). The hallmark is loss of thumb extension and finger MCP extension with preserved wrist extension.

Injury Sequence

1. Force Applied: Typically FOOSH with hyperpronation or direct blow to proximal ulna.
2. Ulna Fractures: Fracture occurs at the proximal or middle third of the ulna. The proximal fragment is pulled into flexion by brachialis and triceps; the distal fragment is pulled into extension and pronation by forearm muscles.
3. Ulnar Shortening/Angulation: Fracture displacement results in shortening and/or angulation of the ulna.
4. Radius Response: The radius cannot shorten due to its articulation with the capitellum proximally and the carpus distally. The intact IOM tethers the radius to the ulna. To accommodate the ulnar shortening, the radius MUST:
   • Dislocate at the PRUJ (Monteggia), OR
   • Fracture (Type IV variant), OR
   • Dislocate at the distal radioulnar joint (Galeazzi if fracture is more distal).
5. Annular Ligament Disruption: The annular ligament tears (or avulses from its periosteal attachment) to allow radial head dislocation. In chronic cases, the ligament may become interposed between the radial head and capitellum, preventing closed reduction.
6. PIN Injury: The nerve is stretched over the dislocated radial head or compressed by hematoma/displaced bone fragments.

Bado Classification

The most widely used classification system, developed by José Luis Bado in 1967, categorizes Monteggia fractures by the direction of radial head dislocation (which correlates with the direction of the ulnar fracture apex and the mechanism of injury). [14]

• Type I (Anterior Dislocation):

  • Incidence: 60-70% of all Monteggia fractures.
  • Radial Head: Dislocated anteriorly.
  • Ulna Apex: Anterior angulation (extension-type fracture).
  • Mechanism: FOOSH with hyperpronation and hyperextension. The ulna fails in tension anteriorly.
  • Classic Presentation: Children, low-energy falls.
  • Associated Injuries: Open fractures (ulnar spike penetrates skin anteriorly), plastic deformation of ulna in young children.
  • PIN Injury: Moderate risk (5-10%).

• Type II (Posterior Dislocation):

  • Incidence: 15-20% (less common but clinically important).
  • Radial Head: Dislocated posteriorly or posterolaterally.
  • Ulna Apex: Posterior angulation (flexion-type fracture).
  • Mechanism: Direct blow to posterior forearm with elbow flexed, or FOOSH with elbow flexed.
  • Associated Injuries: Coronoid fractures (seen in up to 50% of Type II), olecranon fractures (trans-olecranon variant). Functionally similar to "terrible triad" of elbow.
  • PIN Injury: HIGHEST risk (15-20%). The nerve is draped over the posterior dislocation.
  • Prognosis: WORST functional outcomes due to elbow instability from coronoid involvement and high complication rate. [15]

• Type III (Lateral Dislocation):

  • Incidence: 20-25% (almost exclusively pediatric).
  • Radial Head: Dislocated laterally (radial side).
  • Ulna: Greenstick or plastic deformation with lateral (radial) bowing.
  • Mechanism: Varus or adduction force to extended elbow.
  • Classic Presentation: Young children with greenstick fractures.
  • Associated Injuries: Metaphyseal fractures of ulna and radius.
  • PIN Injury: Low risk.
  • Note: Extremely rare in adults (rigid adult bone fractures rather than bowing).

• Type IV (Combined/Variant):

  • Incidence: 1-5% (rare).
  • Radial Head: Dislocated anteriorly.
  • Ulna: Fracture of proximal ulna.
  • Radius: ALSO fractured at proximal or middle third (combined fracture of both radius AND ulna shafts).
  • Mechanism: High-energy axial loading.
  • Associated Injuries: Severe soft tissue injury, neurovascular injury.
  • Treatment Challenge: Both bones must be stabilized; radial head may remain unstable even after ulnar fixation.

Modern Variants and Expanded Classification

Recent literature recognizes additional complex injury patterns that do not fit neatly into Bado's classification: [16]

• Monteggia-Equivalent (Trans-Olecranon Monteggia): Fracture through the olecranon with associated radial head dislocation. Essentially a Bado II variant with fracture line through olecranon rather than ulnar shaft.
• Trans-Ulnar Fracture-Dislocation: Complex coronoid fractures with ulnar shaft or olecranon fractures and radiocapitellar instability. Increasingly recognized as a distinct entity requiring specialized treatment. [17]
• Monteggia Variant with Radial Neck/Head Fracture: Monteggia pattern with concomitant radial head or neck fracture (in addition to radial head dislocation). Significantly complicates treatment.

---

4. Clinical Presentation

Symptoms

• Pain: Severe pain in the elbow, proximal forearm, and sometimes radiating to the wrist.
• Deformity: Visible angulation of the forearm, prominence of the radial head (palpable in antecubital fossa in Type I, posterolaterally in Type II).
• Swelling: Rapid onset of diffuse elbow and forearm swelling.
• Loss of Function: Inability to flex, extend, pronate, or supinate the elbow/forearm. Patients typically hold the arm in a protective position.
• Numbness/Weakness: If PIN injured, patients may report inability to extend fingers or thumb (often not appreciated acutely due to pain).

Signs

Inspection

• Deformity:
  • Ulnar angulation visible and palpable.
  • Radial Head Prominence:
    • Type I: Palpable anteriorly in the antecubital fossa (anterior to the lateral epicondyle).
    • Type II: Palpable posterolaterally, posterior to the lateral epicondyle.
    • Type III: Palpable laterally (rare in adults).
• Skin Assessment:
  • Check for open fracture (more common in Type I due to anterior ulnar spike). Open fractures complicate management and increase infection risk. [18]
  • Lacerations, abrasions, or contusions suggesting direct trauma.

Palpation

• Bony Tenderness: Diffuse tenderness along the ulna, radial head, and elbow joint.
• Crepitus: Over the fracture site.
• Radial Head: Attempt to palpate the radial head in its normal anatomic position (lateral to the radiocapitellar joint). In Monteggia, it will be palpable in an abnormal position (anteriorly, posteriorly, or laterally depending on Bado type).
• Compartment Assessment: Palpate forearm compartments (volar and dorsal) for tightness, firmness, or tenderness (risk of compartment syndrome in high-energy injuries).

Neurological Examination

Critical: Always perform and document a detailed neurovascular exam before and after reduction/treatment.

• Posterior Interosseous Nerve (PIN) Palsy: [19]

  • Incidence: 10-20% overall (highest in Bado Type II).
  • Test Motor Function:
    • Thumb Extension: "Thumbs Up" test (extensor pollicis longus - EPL). Ask patient to extend thumb at IP joint against resistance.
    • Finger MCP Extension: Ask patient to extend fingers at MCP joints (extensor digitorum communis - EDC). Patient will be unable to extend MCP joints but can extend IP joints (lumbricals/interossei intact).
    • Wrist Extension: PRESERVED (extensor carpi radialis longus and brevis innervated by radial nerve proper before PIN bifurcation). This is the KEY distinguishing feature from a more proximal radial nerve injury.
    • Hand Posture: The hand deviates radially during wrist extension (extensor carpi ulnaris - ECU is weak/paralyzed, while ECRL/ECRB are intact).
  • Sensory Examination: PIN is purely motor; there is NO sensory loss (unlike proximal radial nerve injury which affects sensation over dorsal first web space).
  • Clinical Pearl: PIN palsy is often a neuropraxia (traction injury) and recovers spontaneously in 3-6 months in 80-90% of cases. Document carefully and counsel patient.

• Median Nerve: Check thumb opposition, thumb/index pinch strength (anterior interosseous nerve - AIN), sensation over thumb/index/middle fingers.

• Ulnar Nerve: Check finger abduction/adduction, sensation over small finger and ulnar half of ring finger.

• Radial Nerve (proximal): If wrist extension is LOST (in addition to thumb/finger extension), suspect a more proximal radial nerve injury at the humeral level (e.g., associated humeral shaft fracture).

Vascular Examination

• Radial Pulse: Palpate at wrist. Should be strong and symmetrical to contralateral side.
• Ulnar Pulse: Palpate at wrist (medial to flexor carpi ulnaris).
• Capillary Refill: Should be less than 2 seconds in nail beds.
• Brachial Artery: Rarely injured but should be assessed in high-energy trauma or Type II injuries (artery lies anterior to brachialis and can be kinked or contused by posteriorly displaced radial head).
• Compartment Syndrome: High index of suspicion in high-energy injuries. Pain out of proportion, pain with passive stretch, tense compartments, paraesthesias, pulselessness (late sign).

---

5. Investigations

Imaging

X-Ray (MANDATORY)

• Views Required: TWO JOINT RULE
  • Forearm (AP and lateral) including both wrist AND elbow.
  • Dedicated elbow films (AP and lateral) for detailed assessment of radiocapitellar relationship.
• The Golden Rule: "If you see a forearm fracture, you MUST see both joints (wrist and elbow) or you WILL miss the dislocation."
• Key Radiographic Features:
  • Fracture of proximal or middle third ulna (typically transverse or short oblique).
  • Radiocapitellar Line: A line drawn through the longitudinal axis of the radial shaft MUST bisect the capitellum on ALL views (AP and lateral). This relationship holds regardless of elbow flexion/extension angle. [20]
    • If the line misses the capitellum, the radial head is dislocated.
    • Check BOTH AP and lateral views (lateral view is most sensitive).
  • Assess ulnar fracture pattern (comminution, shortening, angulation).
  • Look for associated fractures: coronoid (Type II), radial head/neck (variants), olecranon (trans-olecranon variant).

CT (SELECTIVE)

• Indications:
  • Type II (Posterior Dislocation): Essential to assess for coronoid fractures (present in 50% of Type II). Coronoid fractures affect stability and treatment planning.
  • Comminuted Ulnar Fractures: To assess fracture configuration and plan surgical approach/fixation.
  • Failed Closed Reduction: To identify interposed soft tissues (annular ligament, joint capsule) preventing reduction.
  • Pre-operative Planning: For complex/variant injuries requiring radial head replacement or ligament reconstruction.
• Protocol: Fine-cut (1-2mm) axial images with coronal and sagittal reconstructions.

MRI (RARE)

• Indications:
  • Suspected interosseous membrane injury (for research/forensic purposes; does not typically change acute management).
  • Chronic cases with suspected soft tissue interposition.
  • Assessment of annular ligament integrity in chronic dislocations prior to reconstruction.

Laboratory Studies

• Routine Pre-operative Labs: Complete blood count (CBC), coagulation profile (PT/INR, aPTT), type and screen.
• Special Considerations:
  • If open fracture: Wound cultures (after debridement), elevated WBC suggests infection.
  • If compartment syndrome suspected: Creatine kinase (CK) and myoglobin (for rhabdomyolysis), renal function tests.

---

6. Management Algorithm

                         MONTEGGIA FRACTURE SUSPECTED
                                    ↓
                    ASSESS NEUROVASCULAR STATUS (PIN!)
                                    ↓
                         OBTAIN IMAGING (Forearm XR)
                         (INCLUDE WRIST AND ELBOW)
                                    ↓
                    CONFIRM DIAGNOSIS (Radiocapitellar Line)
                                    ↓
                         OPEN FRACTURE?
                    ┌──────────┴──────────┐
                   YES                   NO
                    ↓                     ↓
          URGENT DEBRIDEMENT      ASSESS AGE/COMPLEXITY
          + ANTIBIOTICS                   ↓
          + TETANUS                ┌──────┴──────┐
                ↓                CHILD          ADULT
                └─────────┬──────┘               ↓
                          ↓                 SURGICAL FIXATION
                    ATTEMPT CLOSED         (ORIF ULNA)
                    REDUCTION                    ↓
                    (MUA + Splint)         COMPRESSION PLATING
                          ↓                 (3.5mm LCP/DCP)
                  CHECK REDUCTION                ↓
                  (Radiocapitellar)       ASSESS RADIAL HEAD
                  ┌──────┴──────┐         REDUCTION
                YES            NO          ┌──────┴──────┐
                 ↓              ↓        YES            NO
            LONG ARM       FAILED CR      ↓              ↓
            CAST           → ORIF     POST-OP       OPEN REDUCTION
            (Supination    (Same as      REHAB       RADIAL HEAD
            Type I/II,     Adult)                    ┌──────┴──────┐
            Neutral                              REDUCIBLE     IRREDUCIBLE
            Type III)                                 ↓              ↓
                 ↓                              ANNULAR LIG     ANNULAR LIG
            FOLLOW-UP XR                         REPAIR      INTERPOSITION
            (1, 2, 6 wks)                                    → REMOVE
                 ↓                                           → REPAIR/
            STABLE?                                          RECONSTRUCT
            ┌──────┴──────┐
          YES            NO
           ↓              ↓
        REHAB        REVISION
                     SURGERY

---

7. Management Protocols

Acute Management (Emergency Department)

1. Resuscitation: ATLS protocol if polytrauma. Assess airway, breathing, circulation.
2. Neurovascular Examination: BEFORE any manipulation. Document PIN function, radial/ulnar pulses.
3. Analgesia: Adequate pain control (opiate analgesia, local hematoma block, or procedural sedation for reduction attempts).
4. Tetanus Prophylaxis: If open fracture or contaminated wound.
5. Antibiotics: If open fracture (cefazolin 2g IV + gentamicin 5mg/kg IV for Gustilo I/II; add penicillin for Gustilo III/farm injuries).
6. Splinting: Apply above-elbow posterior splint in position of comfort (typically 90 degrees flexion) to immobilize fracture and prevent further neurovascular injury. Do NOT attempt aggressive manipulation in ED unless trained orthopaedic surgeon available.
7. Orthopaedic Referral: URGENT. All Monteggia fractures in adults require surgical consultation. Same-day or next-day surgery for closed fractures; URGENT surgery (within 6-12 hours) for open fractures.

Surgical Fixation (Adult Gold Standard)

Indications

• ALL adult Monteggia fractures (closed reduction is rarely successful in adults due to muscle forces and rigid bone).
• Pediatric failures of closed reduction.
• Open fractures (after debridement).

Technique: Open Reduction Internal Fixation (ORIF) of Ulna [21]

1. Approach:

   • Posterior approach to ulna (subcutaneous border - minimal soft tissue dissection required).
   • Make longitudinal incision over subcutaneous border of ulna from olecranon to mid-shaft.
   • Minimal soft tissue stripping (preserve periosteal blood supply).

2. Reduction:

   • Reduce ulna fracture anatomically. Critical: Restore EXACT length and alignment.
   • Use large pointed reduction clamps to hold reduction.
   • Check rotational alignment (align subcutaneous border, posterior cortex).

3. Fixation:

   • Compression Plating: 3.5mm DCP (dynamic compression plate) or LCP (locking compression plate).
   • Apply plate to dorsal or medial surface of ulna (avoid volar surface where interosseous membrane attaches).
   • Achieve lag screw compression through plate if possible (converts shear forces to compressive forces).
   • Minimum 6 cortices (3 screws) proximal and distal to fracture.
   • Use bicortical screws (engage both near and far cortex).

4. Assess Radial Head Reduction:

   • Intra-operative fluoroscopy: Check radiocapitellar line on AP and lateral views after ulnar fixation.
   • Manually pronate/supinate forearm: Radial head should track smoothly in radiocapitellar joint.
   • "The Pop": Often, as the plate reduces the ulna to anatomical length, the radial head "pops" back into place spontaneously (ligamentotaxis).

5. Irreducible Radial Head:

   • If radial head remains dislocated despite anatomical ulnar reduction, suspect soft tissue interposition (annular ligament, joint capsule).
   • Open Reduction of Radial Head:
     • Approach: Lateral Kocher approach (interval between extensor carpi ulnaris and anconeus - internervous plane) or Kaplan approach (anterior, between brachioradialis and extensor carpi radialis longus).
     • Identify and extract interposed annular ligament ("fish out" using small forceps).
     • Reduce radial head into radiocapitellar joint.
     • Repair annular ligament (primary repair end-to-end if tissue quality good).
     • If annular ligament irreparable, consider reconstruction (see Chronic Monteggia section).

6. Associated Fractures:

   • Radial Head/Neck Fracture: If Mason Type I/II (minimally displaced), treat non-operatively after ulnar fixation. If Mason Type III (comminuted), consider radial head replacement (metallic prosthesis).
   • Coronoid Fracture (Type II Monteggia): Fix if > 50% of coronoid height or if elbow unstable after ulnar fixation. Use suture lasso technique or small fragment screws (anterior approach).

7. Closure:

   • Copious irrigation.
   • Close fascia, subcutaneous tissue, and skin in layers.
   • Apply above-elbow posterior splint in 90 degrees flexion and forearm in supination (Type I) or neutral (Type II).

Post-operative Protocol

• Immobilization: Posterior splint for 1-2 weeks until wound healed and swelling subsided.
• Early Motion: Begin gentle active range-of-motion exercises at 2 weeks (critical to prevent stiffness).
  • Elbow flexion/extension.
  • Forearm pronation/supination.
  • Avoid passive stretching or aggressive physiotherapy for 6 weeks (risk of heterotopic ossification).
• Radiographs: Post-operative XR in recovery room, then 2 weeks, 6 weeks, 12 weeks, 6 months.
• Weight-Bearing: No lifting > 1kg for 6 weeks. Gradual return to full activities at 3-4 months once radiographic union confirmed.
• Plate Removal: Not routinely required unless symptomatic prominence or patient preference (can remove after 12-18 months once union solid).

Pediatric Management

Closed Reduction Technique [22]

Type I (Anterior Dislocation):

1. Sedation: Procedural sedation (ketamine or propofol) or general anesthesia.
2. Reduction Maneuver:
   • Assistant applies gentle longitudinal traction on forearm.
   • Flex elbow to 110-120 degrees (relaxes biceps tendon which pulls radial head anteriorly).
   • Supinate forearm fully (tightens interosseous membrane, pulls radius into alignment).
   • Apply direct pressure over radial head posteriorly (push head back into joint).
   • Often a palpable/audible "clunk" as head reduces.
3. Check Reduction: Fluoroscopy or XR (radiocapitellar line).
4. Immobilization: Above-elbow cast in 90-110 degrees flexion and full supination for 4-6 weeks.

Type II (Posterior Dislocation):

1. Reduce with elbow in extension, forearm neutral rotation, with direct anterior pressure on radial head.

Type III (Lateral Dislocation):

1. Reduce with valgus stress and direct medial pressure on radial head.

Indications for Surgery in Children

• Failed closed reduction (radial head does not reduce or re-dislocates).
• Open fractures.
• Age > 12 years (adolescents approaching skeletal maturity).
• Irreducible fractures (soft tissue interposition).

Chronic Missed Monteggia (Late Presentation) [23,24]

Definition: Monteggia injury diagnosed > 4 weeks after initial trauma.

Pathophysiology:

• Ulna heals in shortened and/or angulated position.
• Radial head remains dislocated and undergoes adaptive changes: overgrowth, deformity, cartilage degeneration.
• Annular ligament heals in abnormal position or becomes attenuated/absent.
• Capitellum develops adaptive flattening from lack of normal radial head articulation.

Clinical Presentation:

• Elbow pain (anterolateral in Type I, posterolateral in Type II).
• Loss of elbow flexion (radial head blocks flexion).
• Loss of forearm rotation (especially supination).
• Cubitus valgus deformity (progressive).
• PIN palsy (delayed onset - nerve stretched over chronic dislocation).
• Limitation of activities (difficulty with throwing, lifting, overhead activities).

Surgical Treatment:

1. Ulnar Osteotomy + Open Reduction of Radial Head (Children less than 12 years, less than 3 years post-injury):

• Technique:
  • Ulnar osteotomy at site of original malunion.
  • Lengthen ulna with interposition bone graft (from olecranon or iliac crest) OR gradual distraction with external fixator.
  • Restore anatomical ulnar length (compare to contralateral side).
  • Open reduction of radial head: Lateral approach (Kocher).
  • Excise fibrous tissue from radiocapitellar joint.
  • Reduce radial head (often requires significant force).
  • Annular Ligament Reconstruction: Bell-Tawse procedure (strip of triceps fascia passed around radial neck and sutured to itself to create a new "sling").
  • Stabilize with temporary K-wire across radiocapitellar joint (remove at 4 weeks).
• Outcomes: Success rate 60-80% in children if surgery performed within 2-3 years of injury. High risk of re-dislocation (10-30%) especially if > 3 years post-injury. [25]

2. Radial Head Excision (Adults, > 3 years post-injury):

• Indications: Painful chronic dislocation in adults, failed reconstruction, severe arthritic changes.
• Technique: Radial head excision via lateral approach. Smooth radial neck.
• Outcomes: Relieves pain in 70-80% but sacrifices rotation (average 20-30% loss of supination). Risk of proximal migration of radius over time (wrist pain, ulnar-sided wrist pain). Generally avoided in young active patients.
• Alternative: Radial head replacement (metallic prosthesis) if radial head severely arthritic but reconstruction attempted.

---

8. Complications

Early Complications

1. Posterior Interosseous Nerve (PIN) Palsy

• Incidence: 10-20% overall (5-10% Type I, 15-20% Type II, 5% Type III).
• Mechanism: Traction injury during radial head dislocation, compression by hematoma, contusion by bone fragment, or iatrogenic during reduction/surgery.
• Presentation: Loss of thumb extension (EPL), finger MCP extension (EDC), with PRESERVED wrist extension (ECRL/ECRB).
• Management:
  • Expectant (first 3-4 months): 80-90% of PIN palsies are neuropraxias and recover spontaneously within 3-6 months.
  • Splint hand: Dynamic splint to support MCP extension, prevent flexion contractures.
  • Serial examinations: Document recovery monthly (return of EPL first sign of recovery).
  • Electromyography (EMG)/Nerve Conduction Studies (NCS): At 3 months if no clinical recovery. Differentiates neuropraxia (recovers) from neurotmesis (does not recover).
  • Surgical Exploration: If no recovery by 3-4 months AND EMG shows no signs of reinnervation. Explore PIN, perform neurolysis, repair if nerve transected.
• Prognosis: Good (80-90% full recovery). Worse if nerve injured during surgery or if neurotmesis. [26]

2. Compartment Syndrome

• Incidence: Rare (less than 5%) but catastrophic if missed.
• Risk Factors: High-energy trauma, vascular injury, prolonged ischemia time, tight casts/splints.
• Diagnosis: Clinical (5 Ps: Pain out of proportion, Pallor, Pulselessness, Paraesthesias, Paralysis). LATE signs. PAIN with passive stretch is EARLIEST sign.
• Compartment Pressure Measurement: If diagnosis unclear, measure compartment pressures (> 30mmHg absolute or delta pressure less than 30mmHg [diastolic pressure - compartment pressure] is diagnostic).
• Management: URGENT fasciotomy (volar and dorsal compartments). Delay > 6-8 hours results in permanent muscle necrosis and Volkmann's contracture.

3. Vascular Injury

• Incidence: Rare (less than 2%). Most common in Type II (posterior dislocation kinks brachial artery) and high-energy Type IV.
• Presentation: Absent or diminished pulses, cool extremity, prolonged capillary refill, expanding hematoma.
• Management: Immediate vascular surgery consultation. CT angiography if patient stable. Surgical exploration, repair (primary repair or vein graft interposition).

4. Open Fracture

• Incidence: 10-20% (higher in Type I due to anterior spike of ulna penetrating skin).
• Management: Urgent surgical debridement (less than 6 hours), IV antibiotics (cefazolin + gentamicin ± penicillin), tetanus, ORIF (primary or staged depending on contamination), wound management (delayed primary closure or VAC therapy).

Late Complications

1. Stiffness

• Incidence: Common (30-50% have some degree of stiffness). [27]
• Presentation: Loss of elbow flexion/extension (average loss 10-20 degrees), loss of forearm pronation/supination (average loss 20-30 degrees).
• Risk Factors: Delayed surgery, inadequate reduction, prolonged immobilization, Type II, associated coronoid fractures.
• Management:
  • Prevention: Early range-of-motion exercises (start at 2 weeks post-op).
  • Physiotherapy: Gentle active ROM, avoid aggressive passive stretching (risk of heterotopic ossification).
  • Surgical Release: If severe stiffness (> 50% loss of ROM) persists > 12 months, consider capsular release + hardware removal.

2. Heterotopic Ossification (HO)

• Incidence: 5-15% (higher in Type II, high-energy trauma, delayed surgery, aggressive physiotherapy).
• Presentation: Ectopic bone formation in soft tissues (interosseous membrane, elbow capsule, PRUJ). Progressive loss of rotation.
• Radiographic Appearance: Calcification/ossification between radius and ulna (interosseous membrane), around radial head.
• Severe Form: Radioulnar synostosis (bony bridge between radius and ulna) - complete loss of pronation/supination.
• Management:
  • Prevention: Early gentle ROM, avoid passive stretching, NSAIDs (indomethacin 25mg TID for 6 weeks post-op - consider if high risk).
  • Observation: If asymptomatic or mild.
  • Surgical Excision: If severe functional limitation, wait until HO "matures" (12-18 months post-injury - bone scan shows no uptake). Excise HO, post-op NSAIDs + radiation therapy (single dose 7-8 Gy within 24 hours to prevent recurrence).

3. Chronic Radial Head Dislocation (Missed/Failed Reduction)

• Incidence: 5-10% (higher if missed diagnosis, inadequate ulnar reduction, soft tissue interposition).
• Presentation: Persistent elbow pain, loss of flexion, loss of rotation, cubitus valgus.
• Management: See "Chronic Missed Monteggia" section above. Ulnar osteotomy + annular ligament reconstruction (children) or radial head excision (adults).

4. Elbow Instability

• Incidence: Rare (less than 5%) if ulna adequately reduced and radial head reduced. Common in Type II with coronoid fractures.
• Presentation: Elbow subluxation or dislocation during ROM, feeling of "giving way".
• Management: Hinged external fixator to allow motion while protecting repair, ligament reconstruction (lateral collateral ligament complex), coronoid fixation.

5. Nonunion/Malunion of Ulna

• Incidence: less than 5% (rare with modern plating techniques).
• Risk Factors: Inadequate fixation, infection, high-energy trauma with soft tissue stripping.
• Presentation: Persistent pain, motion at fracture site, loss of rotation (if malunion shortens ulna).
• Management: Revision ORIF with bone grafting (autograft from iliac crest).

6. Post-Traumatic Arthritis

• Incidence: 20-50% radiographic evidence at long-term follow-up (> 10 years), but most asymptomatic. [28]
• Risk Factors: Intra-articular involvement (coronoid fractures), cartilage injury during dislocation, chronic instability.
• Presentation: Elbow pain with activity, crepitus, loss of motion.
• Management: NSAIDs, activity modification, physiotherapy. Severe cases may require elbow arthroscopy (debridement), radial head excision, or total elbow arthroplasty (salvage in elderly).

---

9. Outcomes and Prognosis

Acute Monteggia - Surgically Treated

Landmark Study: Ring et al. (1998) [29]

• Retrospective review of 24 adult Monteggia fractures treated with ORIF.
• Excellent/Good Results: 70% if:
  1. Ulna rigidly fixed with compression plating.
  2. Anatomical radial head reduction confirmed.
  3. Early motion started within 2-3 weeks.
• Poor Results: 30%. Associated with:
  • Type II injuries.
  • Associated radial head fractures.
  • Coronoid fractures.
  • Delayed surgery (> 2 weeks).

Recent Systematic Review: Nieboer et al. (2024) [30]

• Analyzed outcomes of trans-ulnar fracture-dislocations (includes Monteggia Type II and variants).
• Union Rate: 95% at 3-6 months with plate fixation.
• Complications: 40% complication rate (highest: stiffness 30%, HO 15%, PIN palsy 12%).
• Functional Outcomes: Average DASH score 15-20 (mild disability), Mayo Elbow Performance Score 80-85 (good to excellent).
• Return to Work: 80% return to pre-injury work by 6 months.

Pediatric Monteggia

Study: Roper et al. (2022) [31]

• Compared open vs closed pediatric Monteggia fractures.
• Closed Injuries: 90% excellent outcomes with closed reduction.
• Open Injuries: 70% excellent outcomes (higher complication rate, infection risk, nerve injury).
• Re-dislocation Rate: 5-10% (highest if reduction inadequate or immobilization non-compliant).

Chronic/Missed Monteggia

Study: Zheng et al. (2020) [32]

• Surgical reconstruction of missed Monteggia in children.
• Success Rate: 65% good-to-excellent outcomes if surgery less than 3 years post-injury.
• Re-dislocation Rate: 25% (high compared to acute treatment).
• Factors Predicting Success:
  • Younger age (less than 8 years).
  • Shorter duration since injury (less than 18 months).
  • Adequate ulnar lengthening.
  • Annular ligament reconstruction.

Prognostic Factors

Good Prognosis:

• Bado Type I or III.
• Acute treatment (less than 2 weeks).
• Anatomical reduction of ulna and radial head.
• Rigid fixation (plate).
• Early mobilization.
• No associated fractures (radial head, coronoid).
• Pediatric patients (remodeling potential).

Poor Prognosis:

• Bado Type II (posterior dislocation).
• Delayed diagnosis/treatment (> 4 weeks).
• Associated coronoid or radial head fractures.
• Open fractures (infection risk).
• Persistent PIN palsy (> 6 months suggests neurotmesis).
• High-energy mechanism (polytrauma, vascular injury).

---

10. Evidence & Guidelines

Key Landmark Papers

1. Bado JL (1967): The Monteggia lesion. Clin Orthop Relat Res. 50:71-86.

   • Original classification system (Types I-IV) still used universally today.

2. Ring D, Jupiter JB, et al. (1998): Monteggia fractures in adults. J Bone Joint Surg Am. 80(12):1733-1744.

   • Established surgical fixation (ORIF ulna) as gold standard for adults.
   • Demonstrated importance of anatomical reduction and early motion.

3. Rehim SA, Maynard MA, et al. (2014): Monteggia fracture dislocations: a historical review. J Hand Surg Am. 39(7):1384-1394.

   • Comprehensive historical review and evolution of treatment principles.

Current Best Practice Guidelines

• Adult Monteggia: ORIF of ulna with compression plating (3.5mm LCP/DCP), anatomical reduction, early ROM (2 weeks).
• Pediatric Monteggia: Attempt closed reduction first (success rate 85-90%). If failed, proceed to ORIF. Immobilize in supination (Type I) for 4-6 weeks.
• Type II Injuries: Obtain CT to assess coronoid. Fix coronoid if > 50% height or if unstable after ulnar fixation.
• Chronic Monteggia (Pediatric): Ulnar osteotomy + annular ligament reconstruction if less than 3 years post-injury and age less than 12 years. Otherwise radial head excision.
• PIN Palsy: Expectant management for 3-4 months (splint hand). Explore if no recovery by 4 months.

Areas of Ongoing Research

• Optimal management of Monteggia variants (trans-ulnar fracture-dislocations, radial head fractures).
• Role of radial head replacement vs repair in complex injuries.
• Long-term outcomes (> 20 years) and arthritis development.
• Prevention of heterotopic ossification (optimal NSAIDs regimen, role of radiation).

---

11. Patient Explanation

What is a Monteggia fracture?

You have broken one of the two bones in your forearm (the ulna) and the force of the injury has pushed the other bone (the radius) out of the elbow joint. Think of it as a "double whammy"

• a fracture and a dislocation together. This injury was first described over 200 years ago by an Italian surgeon named Monteggia.

Why didn't the doctors notice the dislocation at first?

The ulna fracture is obvious on X-rays because the broken bone is very visible. However, the radial head dislocation can be subtle and is missed in about 1 in 3 cases if the doctor doesn't specifically look for it by checking the "radiocapitellar line" (an imaginary line that should pass through the center of the elbow joint). That's why we always take X-rays of the entire forearm including both the wrist and elbow when we suspect a forearm fracture.

Why do I need surgery?

In adults, the muscles and forces around the forearm are too strong to hold the broken bone in the correct position with just a cast. If the ulna heals crooked or shortened, the radius cannot sit properly in the elbow joint, and your arm will be permanently stiff and weak. Surgery allows us to put a metal plate on the ulna to hold it in perfect position while it heals. Once the ulna is straight and the correct length, the radius usually pops back into the elbow joint on its own.

What happens during the surgery?

We make a small incision along the back of your forearm where the ulna bone is just under the skin. We line up the broken pieces perfectly and hold them together with a metal plate and screws. We then check with X-rays during surgery to make sure the radius has gone back into the elbow joint. The whole operation takes about 1-2 hours. You'll have a splint on your arm for the first 2 weeks, then we'll start gentle motion exercises.

What about the nerve injury? (If PIN palsy present)

You've noticed that you can't lift your thumb or extend your fingers properly. This is because a nerve called the posterior interosseous nerve (PIN) was stretched when the radius dislocated. The good news is that in 8-9 out of 10 cases, this nerve wakes up on its own over 3-6 months as the swelling goes down and the nerve heals. We'll give you a splint to support your hand and fingers while the nerve recovers. We'll check your nerve function every month. If it hasn't started to recover by 3-4 months, we may need to do another operation to explore the nerve, but this is rarely necessary.

How long until I'm back to normal?

• 2 weeks: Remove splint, start gentle motion exercises.
• 6 weeks: Fracture healing on X-ray, start strengthening exercises.
• 3 months: Return to light work and daily activities.
• 6 months: Return to heavy lifting, sports, and full activities.
• 12 months: Maximal recovery. Some people have mild stiffness or loss of rotation compared to the other arm, but most people regain 80-90% of normal function.

Will I need the plate removed?

The plate does not usually need to be removed unless it bothers you or you specifically request it. If you want it removed, we usually wait at least 12-18 months until the bone is fully healed. Some people choose to leave it in permanently.

What are the risks?

Like all operations, there are risks:

• Infection: less than 5% (we give antibiotics during surgery to reduce this risk).
• Nerve damage: The PIN may not recover (10-20% have permanent weakness).
• Stiffness: Some loss of elbow bending or forearm rotation is common (20-30 degrees on average).
• Bone not healing (nonunion): less than 5% (very rare with modern plates).
• Extra bone formation (heterotopic ossification): 5-15% (can limit motion, may need removal later).
• Radial head stays out: less than 5% (if the ligament is torn badly, the radius may not stay in place and we may need to repair the ligament).

---

12. Examination Focus (Viva Vault)

Viva Question 1: Define the Monteggia fracture-dislocation and how do you diagnose it on X-ray?

Model Answer: A Monteggia fracture-dislocation is a fracture of the proximal or middle third of the ulna with an associated dislocation of the radial head at the proximal radioulnar joint. It was first described by Giovanni Battista Monteggia in 1814.

The diagnosis is made radiographically by applying the radiocapitellar line test: I draw a line along the longitudinal axis of the radial shaft on both AP and lateral views. This line MUST pass through the center of the capitellum regardless of the degree of elbow flexion or extension. If the line misses the capitellum, the radial head is dislocated.

It is critical to obtain two-joint radiographs (forearm films including wrist AND elbow) whenever I see an isolated ulnar shaft fracture, as the radial head dislocation is missed in 30-50% of cases if dedicated elbow films are not obtained.

---

Viva Question 2: Describe the Bado classification and which type has the worst prognosis?

Model Answer: The Bado classification, developed in 1967, categorizes Monteggia fractures based on the direction of radial head dislocation and correlates with the mechanism of injury:

• Type I (Anterior - 60-70%): Radial head dislocated anteriorly, ulna apex anterior angulation. Mechanism is hyperextension and hyperpronation (FOOSH). Most common in children.

• Type II (Posterior - 15-20%): Radial head dislocated posteriorly, ulna apex posterior angulation. Mechanism is direct blow to flexed elbow or FOOSH with elbow flexed. This type has the worst prognosis because:

  • Highest PIN injury rate (15-20%).
  • Frequently associated with coronoid fractures (50%), leading to elbow instability (similar to terrible triad).
  • Poorest functional outcomes and highest complication rate.

• Type III (Lateral - 20-25%): Radial head dislocated laterally, ulna greenstick fracture with lateral bowing. Mechanism is varus force. Almost exclusive to young children. Rare in adults.

• Type IV (Combined - 1-5%): Radial head dislocated anteriorly with fractures of BOTH radius and ulna shafts. High-energy mechanism. Complex treatment.

---

Viva Question 3: How do you manage a chronic missed Monteggia fracture in a 7-year-old child presenting 12 months after injury?

Model Answer: A chronic missed Monteggia in a child is challenging but still potentially salvageable within 2-3 years of injury. My approach would be:

Pre-operative Assessment:

• Clinical examination: Range of motion (elbow flexion/extension, forearm pronation/supination), neurovascular status (delayed PIN palsy can occur).
• Imaging: AP and lateral forearm/elbow X-rays (compare to contralateral side to assess ulnar shortening/angulation). CT scan to assess radial head deformity and capitellum adaptive changes.

Surgical Treatment:

1. Ulnar Osteotomy and Lengthening:

   • Perform osteotomy at site of malunion.
   • Restore anatomical ulnar length (compare to contralateral side - typically need 1-2cm lengthening).
   • Options: Acute lengthening with interposition bone graft (from olecranon or iliac crest) and plate fixation, OR gradual distraction with external fixator (Ilizarov technique).

2. Open Reduction of Radial Head:

   • Lateral approach (Kocher interval between ECU and anconeus).
   • Excise fibrous tissue from radiocapitellar joint.
   • Reduce radial head (often requires significant force and may need to resect overgrown portion of radial head/neck).

3. Annular Ligament Reconstruction:

   • Bell-Tawse procedure: Harvest strip of triceps fascia (or palmaris longus tendon).
   • Pass around radial neck and suture to itself to create new annular sling.
   • Temporarily stabilize with K-wire across radiocapitellar joint (remove at 4 weeks).

4. Post-operative Protocol:

   • Above-elbow cast for 4-6 weeks.
   • Remove K-wire at 4 weeks.
   • Gentle ROM exercises starting at 6 weeks.

Prognosis: Success rate is approximately 65% good-to-excellent outcomes if surgery is performed within 3 years of injury and child is less than 12 years old. Re-dislocation rate is 25%. Factors predicting success include younger age, shorter duration since injury, and adequate ulnar lengthening. If this child were > 3 years post-injury or surgery fails, the alternative would be radial head excision (accept loss of rotation).

---

Viva Question 4: What is the innervation and clinical testing for Posterior Interosseous Nerve palsy, and why is wrist extension preserved?

Model Answer: The Posterior Interosseous Nerve (PIN) is the terminal motor branch of the radial nerve after it bifurcates into superficial (sensory) and deep (motor) branches in the proximal forearm. The PIN passes through the supinator muscle (arcade of Frohse) approximately 4-6 cm distal to the radiocapitellar joint and wraps around the radial neck, making it vulnerable to traction during radial head dislocation.

Muscles Innervated by PIN:

• Extensor pollicis longus (EPL) - thumb IP extension
• Extensor digitorum communis (EDC) - finger MCP extension
• Extensor indicis proprius (EIP) - index finger extension
• Extensor carpi ulnaris (ECU) - wrist extension and ulnar deviation
• Extensor pollicis brevis (EPB) - thumb MCP extension
• Abductor pollicis longus (APL) - thumb abduction

Clinical Testing:

• "Thumbs Up" test: Ask patient to extend thumb at IP joint against resistance (EPL). Inability indicates PIN palsy.
• Finger MCP extension: Ask patient to extend fingers at MCP joints with wrist supported. Inability indicates PIN palsy (but IP extension preserved via lumbricals/interossei).
• Wrist extension: This is the KEY distinguishing feature - PRESERVED in PIN palsy.

Why is Wrist Extension Preserved? The extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB) are innervated by the radial nerve proper BEFORE it bifurcates into superficial and deep branches. Therefore, these muscles are NOT innervated by the PIN and remain functional. The patient CAN extend the wrist but the hand deviates radially (because ECU is weak/paralyzed). This distinguishes PIN palsy from a more proximal radial nerve injury (e.g., humeral shaft fracture) where wrist extension is also lost.

Sensory Examination: PIN is purely motor - there is NO sensory loss (unlike proximal radial nerve injury which affects sensation over the dorsal first web space).

---

Viva Question 5: Why is anatomical reduction of the ulna so critical in Monteggia fractures?

Model Answer: Anatomical reduction of the ulna is the cornerstone of Monteggia fracture treatment because of the principle of ligamentotaxis - the concept that restoring bone alignment restores soft tissue tension and indirectly reduces the dislocation.

Key Principles:

1. "The Ulna Rules the Radius": The radius is tethered to the ulna by:

   • The interosseous membrane (IOM), which acts as a load-bearing structure and maintains the length-tension relationship between the two bones.
   • The annular ligament and PRUJ capsule.
   • When the ulna fractures and shortens/angulates, the radius cannot shorten (it articulates with the capitellum proximally and carpus distally, both fixed points). Therefore, the radius MUST dislocate to accommodate the length discrepancy.

2. Restoring Ulnar Length Reduces Radial Head:

   • By restoring the ulna to its anatomical length and alignment with rigid plate fixation, the IOM is tensioned.
   • This pulls the radius back into alignment with the ulna.
   • The radial head is "pulled" back into the radiocapitellar joint (often with an audible/palpable "pop").
   • In 85-90% of cases, anatomical ulnar reduction ALONE is sufficient to reduce the radial head without direct manipulation.

3. Even 5mm of Shortening is Unacceptable:

   • Cadaveric studies show that as little as 5mm of ulnar shortening results in persistent radial head subluxation or instability.
   • Rotational malalignment also affects radiocapitellar tracking and can prevent reduction.

4. Rigid Fixation is Essential:

   • Compression plating (3.5mm DCP/LCP) achieves rigid fixation that maintains exact length and allows early motion.
   • Cast immobilization alone is inadequate in adults due to muscle forces causing re-displacement.

Therefore, the surgical goal is not just to "fix the ulna" but to achieve perfect anatomical restoration (length, alignment, rotation) to indirectly reduce the radial head and restore normal kinematics of the forearm.

---

13. References

1. Rehim SA, Maynard MA, Sebastin SJ, Puhaindran ME. Monteggia fracture dislocations: a historical review. J Hand Surg Am. 2014;39(7):1384-1394. doi:10.1016/j.jhsa.2014.02.024

2. Delpont M, Louahem D, Cottalorda J. Monteggia injuries. Orthop Traumatol Surg Res. 2018;104(1S):S113-S120. doi:10.1016/j.otsr.2017.04.018

3. Ring D. Monteggia fractures. Orthop Clin North Am. 2013;44(1):59-66. doi:10.1016/j.ocl.2012.08.002

4. Xiao RC, Boatman D, Antuna SA, Morrey BF, Sanchez-Sotelo J. Surgical Management of Complex Adult Monteggia Fractures. J Hand Surg Am. 2021;46(10):906.e1-906.e9. doi:10.1016/j.jhsa.2021.06.011

5. Wong JC, Getz CL, Abboud JA. Adult Monteggia and Olecranon Fracture Dislocations of the Elbow. Hand Clin. 2015;31(4):565-580. doi:10.1016/j.hcl.2015.06.004

6. Matar HE, Akimau P, Barrie J. Surgical treatment of Monteggia variant fracture dislocations of the elbow in adults: surgical technique and clinical outcomes. Eur J Orthop Surg Traumatol. 2017;27(5):599-609. doi:10.1007/s00590-017-1942-4

7. Kim E, Park HW, Lee DH, Lee SC. Three-dimensional analysis of acute plastic bowing deformity of ulna in radial head dislocation or radial shaft fracture using a computerized simulation system. J Shoulder Elbow Surg. 2012;21(10):1365-1370. doi:10.1016/j.jse.2011.09.017

8. Jagiella-Lodise O, Waryasz G, Reddy S, et al. Monteggia fractures and the Bado classification: an urban trauma center experience. J Clin Orthop Trauma. 2025;59:102575. doi:10.1016/j.jcot.2024.102575

9. Kokkalis ZT, Ballas EG, Mpeletsiotis EK, Mavrogenis AF. Surgical Treatment of Monteggia-Like Lesions With a Modified Boyd Approach. J Shoulder Elbow Arthroplasty. 2023;7:24715492231198471. doi:10.1177/24715492231198471

10. Nieboer MJ, Koehler SM, Guitton TG, et al. Surgical treatment and outcomes of trans-ulnar basal coronoid fracture-dislocations. J Shoulder Elbow Surg. 2024;33(9):2023-2031. doi:10.1016/j.jse.2024.02.029

11. Antoon SF, Atiyya A, Gaston T, Ditsios K, Sotereanos DG. Evaluation of Monteggia Fracture Outcomes: Acute to Chronic. Hand (N Y). 2024;19(7):1166-1174. doi:10.1177/15589447231151584

12. Haft M, Hanna P, Giambra K, et al. Pediatric Monteggia Fracture-dislocations and Their Variants: An Analysis of Outcomes and Complications. J Pediatr Orthop. 2025;45(1):e61-e67. doi:10.1097/BPO.0000000000002789

13. Bado JL. The Monteggia lesion. Clin Orthop Relat Res. 1967;50:71-86.

14. Rehim SA, Maynard MA, Sebastin SJ, Puhaindran ME. Monteggia fracture dislocations: a historical review. J Hand Surg Am. 2014;39(7):1384-1394.

15. Nieboer MJ, Koehler SM, Nota SPFT, Chen NC, Eygendaal D, van den Bekerom MPJ. Trans-ulnar fracture dislocations of the elbow: a systematic review and clarification of classification systems. J Shoulder Elbow Surg. 2024;33(2):451-467. doi:10.1016/j.jse.2023.08.023

16. Matar HE, Akimau P, Barrie J. Surgical treatment of Monteggia variant fracture dislocations of the elbow in adults: surgical technique and clinical outcomes. Eur J Orthop Surg Traumatol. 2017;27(5):599-609.

17. Nieboer MJ, Koehler SM, Guitton TG, et al. Surgical treatment and outcomes of trans-ulnar basal coronoid fracture-dislocations. J Shoulder Elbow Surg. 2024;33(9):2023-2031.

18. Roper B, Shi LL, Shields E, et al. Outcomes After Operative Treatment of Pediatric Monteggia Fracture-Dislocations: Comparison Between Open and Closed Injuries. J Pediatr Orthop. 2022;42(8):e896-e901. doi:10.1097/BPO.0000000000002215

19. Amaral JZ, Williams J, Lawrence JTR, Pandya NK. Examining Preoperative Risk Factors for Nerve Injury in Pediatric Monteggia Fracture-Dislocations. J Bone Joint Surg Am. 2025;107(2):125-131. doi:10.2106/JBJS.24.00530

20. Ring D, Jupiter JB, Simpson NS. Monteggia fractures in adults. J Bone Joint Surg Am. 1998;80(12):1733-1744.

21. Xiao RC, Boatman D, Antuna SA, Morrey BF, Sanchez-Sotelo J. Surgical Management of Complex Adult Monteggia Fractures. J Hand Surg Am. 2021;46(10):906.e1-906.e9.

22. Matheron G, Plancq MC, Herbaux B, Gouron R. Monteggia fracture‑dislocations in children: a structured approach to management. Orthop Traumatol Surg Res. 2025;111(1):103802. doi:10.1016/j.otsr.2024.103802

23. Gryson T, Docteur A, Dujardin C, Lascombes P, Popkov D. The management of chronic paediatric Monteggia fracture-dislocation. J Orthop. 2021;24:52-58. doi:10.1016/j.jor.2021.02.013

24. Zheng ET, Glanzmann MC, Chow W, Howard AW, Alman BA, Pedreira A. Surgical Reconstruction of Missed Monteggia Lesions in Children. J Pediatr Orthop. 2020;40(10):e959-e965. doi:10.1097/BPO.0000000000001625

25. Dai ZZ, Wang C, Wang XD, Wang Y, Xu YQ. Risk factors for redislocation of chronic Monteggia fracture-dislocation in children after reconstruction surgery. Int Orthop. 2022;46(7):1607-1615. doi:10.1007/s00264-022-05420-1

26. Sandeep PK, Kumar S, Naveen P. Type III Monteggia Fracture-dislocation with Radial Nerve Injury in Adults - A Case Report of two Cases. J Orthop Case Rep. 2023;13(6):63-67. doi:10.13107/jocr.2023.v13.i06.3752

27. Antoon SF, Atiyya A, Gaston T, Ditsios K, Sotereanos DG. Evaluation of Monteggia Fracture Outcomes: Acute to Chronic. Hand (N Y). 2024;19(7):1166-1174.

28. Delpont M, Louahem D, Cottalorda J. Monteggia injuries. Orthop Traumatol Surg Res. 2018;104(1S):S113-S120.

29. Ring D, Jupiter JB, Simpson NS. Monteggia fractures in adults. J Bone Joint Surg Am. 1998;80(12):1733-1744.

30. Nieboer MJ, Koehler SM, Nota SPFT, Chen NC, Eygendaal D, van den Bekerom MPJ. Trans-ulnar fracture dislocations of the elbow: a systematic review and clarification of classification systems. J Shoulder Elbow Surg. 2024;33(2):451-467.

31. Roper B, Shi LL, Shields E, et al. Outcomes After Operative Treatment of Pediatric Monteggia Fracture-Dislocations: Comparison Between Open and Closed Injuries. J Pediatr Orthop. 2022;42(8):e896-e901.

32. Zheng ET, Glanzmann MC, Chow W, Howard AW, Alman BA, Pedreira A. Surgical Reconstruction of Missed Monteggia Lesions in Children. J Pediatr Orthop. 2020;40(10):e959-e965.