Adult Monteggia Fracture-Dislocation — ORIF

Surgical Indications

Absolute Indications

• All adult Monteggia fracture-dislocations (Bado Types I-IV) — non-operative treatment in adults has unacceptably high rates of redislocation, malunion, and chronic instability
• Irreducible radial head after attempted closed reduction, suggesting interposition of the annular ligament, capsule, or fracture fragment
• Open Monteggia fractures — require urgent debridement and fixation regardless of Bado type
• Monteggia fracture with associated neurovascular injury — PIN palsy with clinical evidence of entrapment, or vascular injury

Relative Indications

• Bado Type II with associated radial-head fracture — requires radial-head fixation or replacement in addition to ulna plating
• Bado Type II with coronoid fracture involving greater than 50% of coronoid height — requires coronoid fixation for elbow stability
• Chronic unreduced Monteggia (presenting greater than 6 weeks after injury) — requires more complex reconstruction: ulna osteotomy, plate fixation, and annular ligament reconstruction (Bell-Tawse procedure)
• Pathological fracture of the proximal ulna with radial-head dislocation in metastatic disease

Contraindications

Absolute:

• None for the injury itself — virtually all adult Monteggia fractures require surgical fixation

Relative:

• Severe medical comorbidity precluding general or regional anaesthesia
• Active infection at the surgical site (defer until resolved)
• Patient non-ambulatory with end-stage disease where the functional demands do not justify surgical risk

Evidence for Non-Operative Treatment

Paediatric Exception

Non-operative treatment is the standard for most paediatric Monteggia fractures because the annular ligament has good healing potential in children, the ulna remodels with growth, and closed reduction with casting is successful in a majority of cases. This paediatric principle does NOT apply to adults.

Adult Evidence Against Non-Operative Treatment

• In adults, the proximal ulna has minimal remodelling potential and the annular ligament does not heal in a reduced position without anatomic ulnar fixation
• Non-operative management of adult Monteggia fractures results in high rates of redislocation of the radial head, painful proximal radioulnar joint instability, restricted forearm rotation, and early post-traumatic arthritis
• Multiple case series report poor outcomes with non-operative treatment in adults: persistent dislocation, malunion of the ulna with secondary cubitus valgus or varus, and progressive disability
• The standard of care in adults is ORIF of the ulna for all Bado types

Evidence for Surgery

Plate Fixation of the Ulna — The Definitive Treatment

The established surgical principle across all Bado types in adults is that anatomic reduction and stable plate fixation of the ulna fracture restores the normal proximal radioulnar joint anatomy and allows indirect reduction of the radial head. This was established by series in the 1980s-2000s showing reliable radial-head reduction after ulna plating in greater than 90% of cases.

Key surgical evidence:

• Anatomic plate fixation of the ulna with 3.5 mm LCDCP or locking compression plate achieves indirect reduction of the radial head in greater than 90% of Bado I and III cases and 80-85% of Bado II cases
• Persistent radial-head dislocation after ulna fixation is most commonly caused by residual ulnar malreduction — re-reduce and re-plate the ulna before accepting persistent displacement
• In Bado Type II, associated injuries to the radial head and coronoid must be addressed to achieve a stable elbow

Bado Type II and the Jupiter Sub-Classification

Jupiter et al. sub-classified Bado Type II based on associated injuries, which guides the operative plan:

Key Evidence

Proximal Ulna — Surgical Anatomy

Olecranon and Coronoid Process

• The olecranon is the proximal extension of the ulna, forming the proximal articular surface of the ulnohumeral joint with the trochlea
• The coronoid process projects anteriorly from the base of the olecranon and is the primary anterior buttress against posterior elbow subluxation — it is the keystone of elbow stability
• The trochlear notch (sigmoid notch) is the deep articular concavity between the olecranon and coronoid, articulating with the trochlea; the notch is oriented approximately 45 degrees to the long axis of the ulna
• The proximal dorsal angulation (sag) of the ulna is a posterior bow at the metaphyseal-diaphyseal junction that is critical to restore — loss of this angle leads to reciprocal radial-head malalignment
• The ulna shaft is subcutaneous along its posterior border for most of its length, making surgical exposure straightforward but the thin soft-tissue envelope vulnerable

The Annular Ligament and Proximal Radioulnar Joint

• The annular ligament encircles the radial head, attaching to the anterior and posterior margins of the radial notch of the ulna (the lesser sigmoid notch)
• It maintains radial-head contact with the capitulum and stabilises the proximal radioulnar joint
• In a Monteggia fracture-dislocation the annular ligament is invariably torn from its ulnar attachment — the ligament ruptures at or near the ulnar insertion, and the radial head dislocates
• After anatomic ulna plating, the annular ligament heals in the reduced position in most cases; primary repair is rarely needed in acute Monteggia injuries
• In chronic Monteggia lesions (greater than 6 weeks), the annular ligament may scar and shorten, preventing reduction of the radial head — reconstruction with a palmaris longus or fascia lata graft (Bell-Tawse procedure) is then required

Posterior Interosseous Nerve (PIN)

• The PIN branches from the radial nerve approximately 2-3 cm distal to the lateral epicondyle, anterior to the radiocapitellar joint
• It enters the supinator muscle through the arcade of Frohse — a fibrous arch at the proximal border of the supinator that can compress the nerve
• The PIN then wraps around the proximal radial neck and runs along the posterior surface of the radius deep to supinator
• It exits the distal border of the supinator approximately 5-6 cm distal to the radial head
• Supplies: extensor carpi ulnaris, extensor digitorum, extensor digiti minimi, extensor pollicis longus, extensor pollicis brevis, extensor indicis, and abductor pollicis longus. Does NOT supply ECRB (supplied by the radial nerve proximal to the PIN branch)
• Clinical test: ask the patient to extend all fingers and the thumb against resistance; inability to extend MCPs of digits 2-5 = PIN palsy; preserved wrist extension (ECRB intact) distinguishes PIN palsy from high radial nerve palsy

Bado Classification — Detailed

Bado Type I (approximately 60% of adult Monteggia fractures)

• Ulna fracture: anterior angulation at the junction of the proximal and middle thirds (typically at the metaphyseal-diaphyseal junction of the ulna)
• Radial head: anterior dislocation (anterior to the capitulum)
• Annular ligament: ruptured from ulnar attachment, may become interposed in the radiocapitellar joint
• Mechanism: typically a direct blow to the posterior forearm with the elbow flexed and forearm pronated, causing forced pronation with hyperextension
• Outcome after ulna plating: indirect radial-head reduction achieved in greater than 90% of cases — the most reliably reducible type

Bado Type II (approximately 15-20% — the most common adult pattern)

• Ulna fracture: posterior angulation at or near the olecranon/coronoid level (metaphyseal, transverse or comminuted olecranon fracture)
• Radial head: posterior or posterolateral dislocation
• Mechanism: typically a fall onto a flexed elbow with an axial load, driving the olecranon into the trochlea
• Associated injuries (Jupiter subtypes): radial-head fracture, coronoid fracture, olecranon bifracture, lateral collateral ligament disruption — these are the rule, not the exception
• Outcome after ulna plating: indirect reduction in 80-85%; remaining cases require radial-head fixation, coronoid fixation, or LCL repair

Bado Type III (approximately 5% in adults, more common in children)

• Ulna fracture: metaphyseal fracture near the olecranon apex (transverse or short oblique)
• Radial head: lateral (or anterolateral) dislocation
• Mechanism: abduction force on the extended elbow
• PIN risk: highest risk of PIN injury — the laterally displaced radial head can directly impinge on or contuse the PIN
• Outcome after ulna plating: indirect reduction achieved in most cases

Bado Type IV (rare)

• Combined Bado Type I pattern (anterior radial-head dislocation) with fractures of BOTH the radius and ulna at approximately the same level
• Essentially a Monteggia with an associated radial shaft fracture
• Treat both bones with plate fixation; the ulna is fixed first to restore the proximal radioulnar joint

Surgical Approaches

Posterior Approach to the Proximal Ulna

The workhorse approach for most adult Monteggia fractures, providing direct exposure of the olecranon, coronoid, and proximal ulna.

• Position: lateral decubitus or prone with the arm over a padded support, or supine with the arm across the chest
• Incision: longitudinal or gently curved along the subcutaneous ulnar border, centred on the fracture zone, from the tip of the olecranon distally as needed
• Dissection: expose the ulna subperiosteally, protecting the ulnar nerve along the medial side (the nerve lies posterior to the medial epicondyle and passes into the flexor carpi ulnaris — identify and protect it at the proximal end of the approach)
• Extension: proximally the incision can be extended to the tip of the olecranon and the olecranon can be osteotomised (olecranon osteotomy approach) for improved exposure of the trochlear notch and coronoid if needed for complex intra-articular fractures
• Advantages: direct visualisation of the ulna fracture, preserves the extensor mechanism if the olecranon is not osteotomised, allows plate application directly to the posterior ulnar surface

Kocher Approach to the Radial Head

Used when the radial head requires fixation or replacement (Bado Type II with radial-head fracture, or persistent radial-head dislocation after ulna plating requiring open reduction).

• Interval: between anconeus (medial) and extensor carpi ulnaris (lateral) — the Kocher interval
• Key warning: the PIN lies deep to supinator, which forms the floor of this interval — stay on the capsule of the radial head and do not dissect distally beyond the annular ligament without identifying the nerve
• Principles: develop the interval, incise the capsule longitudinally, expose the radial head and neck. Do not detach the LCL from the lateral epicondyle unless specifically planned. Keep the forearm in pronation to move the PIN away from the operative field.

Positioning and Preparation

Patient position: Lateral decubitus on the unaffected side with the affected arm over a padded arm board or hand table, or supine with the arm across the chest. A radiolucent arm support allows intraoperative fluoroscopy in both AP and lateral planes. The lateral decubitus position is preferred because it gives the best lateral fluoroscopy and allows access to both the dorsal ulna and the lateral elbow (Kocher interval) without repositioning.

Tourniquet: Apply an upper-arm pneumatic tourniquet (250 mmHg). In prolonged cases or when extensive exposure is needed, the tourniquet may be released once and the wound packed before re-inflation. Most Monteggia ORIF cases require 90-120 minutes, well within a single tourniquet cycle.

Fluoroscopy: Position the C-arm to obtain true AP and true lateral views of both the elbow (radiocapitellar joint) and the forearm (radial shaft alignment). Verify before draping that both regions are visible on fluoroscopy without moving the arm.

Antibiotic prophylaxis: First-generation cephalosporin (cefazolin 2 g IV) within 60 minutes of incision. Redose if the case exceeds 4 hours.

Consent: Specifically counsel regarding risk of PIN palsy (5-10%, usually transient), nonunion (5-10%), malunion, recurrent instability, stiffness (loss of terminal extension or forearm rotation), infection (less than 2%), and the possibility of further surgery (hardware removal, radial-head excision, secondary reconstruction).

Preparation for combined approaches: If the injury is a Bado Type II with an associated radial-head fracture, prepare the entire arm to the mid-forearm so that a Kocher approach to the lateral elbow can be added without reprepping. Palpate and mark the radial head, lateral epicondyle, olecranon tip, and ulnar shaft subcutaneous border before draping.

Operative Technique — Step-by-Step

Step 1: Radiographic Confirmation and Planning

Before incision, confirm the Bado type, fracture configuration, and any associated injuries on fluoroscopy. Review the preoperative CT for coronoid involvement, radial-head fracture pattern, and lateral collateral ligament status.

If a radial-head fracture is present, plan for both a posterior ulna exposure AND a Kocher lateral elbow exposure. If only the ulna needs plating, a single posterior approach to the ulna suffices.

Step 2: Expose the Proximal Ulna Fracture

Make a longitudinal or gently curved incision along the subcutaneous ulnar border, centred on the fracture zone. Extend proximally to the tip of the olecranon if the fracture is at the olecranon level.

Incise the skin and subcutaneous tissue. Identify the ulnar nerve if the dissection is proximal to the mid-forearm — the nerve runs posterior to the medial epicondyle and enters the flexor carpi ulnaris (FCU). Retract the nerve gently with a vessel loop.

Expose the ulna fracture by subperiosteal dissection, clearing only enough for plate application — do not strip the periosteum widely as it contributes to fracture healing. Remove haematoma and small loose fragments. Irrigate the fracture site.

Step 3: Reduce and Temporarily Fix the Ulna Fracture

Reduce the ulna fracture under direct vision and fluoroscopic guidance. For transverse fractures, use pointed reduction clamps (Weber or Verbrugge). For oblique or comminuted fractures, use lag screw fixation of key fragments before plate application.

Restore the anatomic contour of the proximal ulna — this includes the proximal dorsal angulation (the sag), the coronoid process, and the olecranon. Check on lateral fluoroscopy that the trochlear notch depth and orientation are restored.

Place one or two 1.6 mm or 2.0 mm K-wires across the reduced fracture for provisional fixation. Confirm reduction on AP and lateral fluoroscopy: the ulna cortical alignment must be perfect, the olecranon-coronoid relationship restored, and the radial shaft axis pointing towards the centre of the capitulum on all views.

Step 4: Plate Fixation of the Ulna

Select a 3.5 mm LCDCP or pre-contoured proximal ulna locking plate. The plate should be long enough to provide at least 3 screws (6 cortices) proximal and 3 screws (6 cortices) distal to the fracture. For metaphyseal or highly comminuted fractures, use a longer plate with bridge fixation (screws in the proximal and distal segments only, span the comminuted zone).

Contour the plate to fit the posterior surface of the proximal ulna — the proximal ulna has a natural posterior bow. The plate should sit flush against the cortex without gapping.

Apply the plate and secure with cortical or locking screws. In the proximal fragment (olecranon), use 2.7 mm or 3.5 mm locking screws for angular stability, particularly if the bone is osteoporotic. In the distal fragment, use 3.5 mm cortical screws — consider an interfragmentary lag screw across an oblique fracture line before plate application for additional compression.

Tighten all screws. Confirm stable fixation by gently stressing the fracture under fluoroscopy. Remove the provisional K-wires.

Step 5: Confirm Indirect Radial-Head Reduction

After ulna plate fixation, check the position of the radial head on AP and lateral fluoroscopy. The radiocapitellar line should now pass through the centre of the capitulum on all views. The radial head should be concentrically reduced in the radiocapitellar joint.

If the radial head is reduced: proceed to Step 7 (wound closure) if no associated injuries require treatment. Assess forearm rotation — full pronation and supination should be possible.

Step 6: Manage Persistent Radial-Head Dislocation

If the radial head remains dislocated after anatomic ulna plate fixation:

Step 6a — Re-check the ulna: Remove the distal screws and check the ulnar reduction again on fluoroscopy. Is there residual angulation? Is length restored? Is the sag correct? Re-reduce and re-fix if any deficiency is found. Many persistently dislocated radial heads are the result of subtle ulnar malreduction that was not appreciated on the initial check.

Step 6b — Open inspection of the radiocapitellar joint: If the ulna is confirmed anatomic and the radial head remains dislocated, open the radiocapitellar joint through a Kocher approach. Inspect for interposition of the annular ligament, joint capsule, or small fracture fragments (commonly a coronoid or radial-head fragment). Remove all interposed tissue, reduce the radial head manually, and confirm concentric reduction on fluoroscopy.

Step 6c — Associated radial-head or coronoid fracture (Bado Type II): If the radial head is fractured and cannot be reduced concentrically, perform radial-head fixation or replacement. If the coronoid is fractured and blocking reduction, fix the coronoid through a medial or extended lateral approach.

Step 7: Assess Elbow and Forearm Stability

Before wound closure, perform a systematic stability assessment:

1. Forearm rotation: supinate and pronate the forearm through a full range. Check that the radial head remains reduced throughout the arc of rotation. If the radial head subluxates during rotation, there may be an associated interosseous membrane injury or residual ulnar malreduction.

2. Valgus stress: apply a gentle valgus stress to the elbow in full extension. If there is gapping, suspect lateral collateral ligament disruption (Jupiter Type IIE). Repair the LCL from its lateral epicondyle insertion using suture anchors.

3. Distal radioulnar joint (DRUJ): ballot the ulnar head against the radius at the wrist. If unstable (positive piano-key sign), assess for an Essex-Lopresti lesion (longitudinal forearm instability from interosseous membrane disruption). If present, consider temporary K-wire fixation of the DRUJ in supination and refer for specialist reconstruction.

4. Elbow extension: assess the range of extension. If extension is limited to greater than 30 degrees of flexion contracture, check for posterior impingement from malreduced coronoid fragments, loose bodies, or hardware prominence.

Step 8: Wound Closure and Posterior Splint

Irrigate the wound thoroughly. Close the deep fascia over the plate if possible (this reduces hardware prominence and infection risk). Close subcutaneous tissue with absorbable sutures. Close the skin with staples or non-absorbable sutures.

Apply a long-arm posterior plaster splint with the elbow in approximately 90 degrees of flexion and the forearm in neutral rotation. This protects the fixation while allowing early swelling resolution.

Radial-Head Fixation or Replacement (Bado Type II)

When to Fix vs Replace the Radial Head

• Fixation indicated: Mason Type II (partial head fracture, displaced greater than 2 mm with mechanical block to rotation, and the fragment is large enough for screw fixation with at least 2 screws)
• Replacement indicated: Mason Type III (comminuted radial-head fracture with greater than 3 fragments) or Mason Type IV (radial-head fracture associated with elbow dislocation), where stable internal fixation is not achievable

Radial-Head Fixation Technique (via Kocher Approach)

1. Use the Kocher interval (anconeus-ECU). Keep the forearm in pronation to protect the PIN.
2. Incise the capsule longitudinally. Expose the radial head and neck.
3. Reduce the fracture fragments. Fix with 2.0 mm or 2.4 mm headless compression screws (Acutrak or Herbert) or mini-fragment screws.
4. Confirm stable fixation and full forearm rotation under fluoroscopy.
5. Repair the lateral collateral ligament if detached (suture anchors at the lateral epicondyle).

Radial-Head Arthroplasty

1. Excise the comminuted radial head. Preserve the annular ligament.
2. Trial the prosthesis to restore the correct radial height (compare with the contralateral elbow on fluoroscopy, or use the sigmoid notch depth as a reference).
3. Cement or press-fit the prosthesis. Confirm stable fixation and full forearm rotation.
4. Assess valgus stability — the radial-head prosthesis is a secondary stabiliser against valgus stress; if the LCL is torn and the radial head is absent (excised without replacement), valgus instability is predictably poor.

Post-operative Protocol

Immediate Post-Operative Phase (Day 0-7)

• Immobilisation: Long-arm posterior plaster splint with elbow at 90 degrees flexion, forearm neutral. Splint for comfort and swelling control — not rigid immobilisation of a stable construct.
• Elevation: Elevate the arm above heart level continuously for the first 48 hours to reduce swelling. Finger movement is encouraged immediately.
• Analgesia: Multimodal: paracetamol, NSAID (unless contraindicated), and oral opioid as required for the first 3-5 days.
• Neurovascular check: Document PIN function (finger extension, thumb extension) immediately postoperatively and at 24 and 48 hours. Check ulnar nerve distribution (little finger sensation, intrinsic function).

Early Mobilisation Phase (Week 1-4)

• Elbow: Remove the splint at 7-14 days (at suture/staple removal) if fixation is stable. Begin active-assisted elbow flexion and extension. Do NOT force terminal extension — allow the elbow to regain extension gradually.
• Forearm rotation: Begin gentle active forearm pronation and supination within the patient's pain-free range. Monitor the radial head on follow-up radiographs if any concern about stability.
• Wrist and hand: Full active finger, wrist, and thumb movement from day 1 to maintain PIN-innervated extensor function and prevent stiffness.

Strengthening Phase (Week 4-12)

• Progressive resistance: Begin isometric and then isotonic elbow flexion/extension and forearm rotation exercises from week 4.
• Functional use: Encourage use of the arm for activities of daily living, avoiding heavy lifting (nothing heavier than a cup of tea for the first 4 weeks, then progressive loading).
• Formal physiotherapy: Refer if elbow flexion contracture is greater than 30 degrees at 4 weeks, forearm rotation is less than 50% of the contralateral side, or the patient is not progressing with home exercises.

Return to Function

• Office work: 2-4 weeks (once the splint is removed and early mobilisation established)
• Light manual work: 8-12 weeks
• Heavy manual work and sport: 3-6 months (after confirmed union and full rehabilitation)
• Driving: When the patient can comfortably grip the steering wheel and perform an emergency stop — typically 6-8 weeks

Special Case: Chronic Unreduced Monteggia Lesion

Definition and Presentation

A chronic Monteggia lesion is one presenting greater than 6 weeks (some authors say greater than 4 weeks) after injury. The radial head remains dislocated, the ulna fracture has typically healed in a malunited position, and the annular ligament is scarred and shortened. Patients present with pain, restricted forearm rotation, elbow instability, and progressive deformity.

Surgical Principles

• Ulna osteotomy and plate fixation at the site of malunion (or just distal to it) to restore the correct ulnar alignment, length, and sag
• The osteotomy corrects the ulnar bow and allows the radial head to be reduced under the corrected proximal radioulnar geometry
• Annular ligament reconstruction is almost always required because the original ligament has scarred and contracted — the Bell-Tawse procedure uses a strip of flexor carpi ulnaris or triceps fascia as a graft to reconstruct the annular ligament around the reduced radial head
• Open reduction of the radial head through a Kocher approach after the ulna osteotomy and plate fixation

Outcomes

• Results are inferior to acute Monteggia fixation — stiffness, incomplete radial-head reduction, and recurrent instability are more common
• Younger patients (less than 30 years) tend to have better outcomes
• The longer the delay before surgery, the worse the functional outcome

Special Case: Essex-Lopresti Lesion (Longitudinal Radioulnar Instability)

Recognition

An Essex-Lopresti lesion is disruption of the interosseous membrane (IOM) of the forearm with associated injury to the proximal radioulnar joint (radial-head fracture or dislocation) and the distal radioulnar joint (DRUJ). It creates longitudinal forearm instability: the radius migrates proximally under axial load because the IOM no longer tethers it.

• In the context of Monteggia: a Monteggia fracture-dislocation with IOM disruption and DRUJ instability is a variant of the Essex-Lopresti pattern
• Clinical test: ballot the ulnar head at the wrist (positive piano-key sign), shuck test of the DRUJ, and check for wrist pain with forearm rotation
• Radiographic: widened DRUJ on AP view; positive ulnar variance (radius migrated proximally compared with contralateral wrist)

Management

• Radial head preservation is critical — if the radial head is fractured, fix or replace it; do NOT excise without replacement, as excision leaves the forearm with no proximal restraint against longitudinal migration
• IOM repair or reconstruction is controversial and technically demanding; temporary K-wire fixation of the DRUJ in supination for 4-6 weeks is a practical option
• Late presentation: progressive wrist pain, ulnar wrist impingement, and DRUJ arthrosis

Special Case: Bado Type II with Coronoid Fracture

Why the Coronoid Matters

The coronoid process is the primary anterior buttress of the elbow. In Bado Type II, the posteriorly directed force that fractures the olecranon often simultaneously fractures the coronoid. A fractured coronoid of greater than 50% of its height leaves the elbow vulnerable to recurrent posterior subluxation and posterolateral rotatory instability.

Surgical Principles

• Small coronoid tip fractures (Regan-Morrey Type I): treated non-operatively if the elbow is stable on examination
• Coronoid fractures greater than 50% of height (Regan-Morrey Type II-III): require fixation to restore the anterior buttress — fix through a medial or extended lateral approach using 2.0 mm lag screws or a mini-fragment plate
• Fix the coronoid BEFORE definitive closure of the elbow: after the coronoid is fixed, reassess stability and, if the LCL is torn, repair it with suture anchors