Mastering Monteggia Fracture-Dislocations in Adults: An Intraoperative Guide

Welcome, fellows, to the operating theater. Today, we're tackling a Monteggia fracture-dislocation in an adult patient – a complex injury that demands precision, a thorough understanding of elbow biomechanics, and meticulous surgical technique. This isn't just an ulna fracture; it's a fracture-dislocation of the radiocapitellar joint, a critical injury that, if not addressed anatomically, can lead to devastating long-term disability.

Let’s begin by reviewing the fundamentals.

Understanding Monteggia Lesions: Definition and Classification

The term "Monteggia lesion," coined by Bado, describes any fracture of the ulna associated with a dislocation of the radiocapitellar joint. Historically, Giovanni Monteggia first reported this injury in 1814 as an ulnar fracture with an anterior radial head dislocation. While the exact mechanism of injury remains somewhat controversial, improved fixation methods and surgical techniques have significantly enhanced our ability to achieve predictable, successful outcomes in adults.

Key Classifications and Injury Patterns

The Bado classification, with Jupiter's subclassification for Type II, is our standard framework:

• Type I: The most common. Characterized by an anterior dislocation of the radial head with an ulnar diaphyseal fracture, typically with anterior angulation. Proposed mechanisms include a direct blow to the posterior elbow or a fall on an outstretched arm with a hyperpronated hand, leveraging the radial head anteriorly, or even a violent biceps contraction.
• Type II: Involves a posterior or posterolateral dislocation of the radial head with a posterior angulation of the ulnar diaphysis. This is hypothesized to occur with a supination force that tensions ligaments stronger than bone.
  • Type IIA: Fracture at the trochlear notch, involving the distal olecranon and coronoid.
  • Type IIB: Ulnar fracture at the metaphyseal-diaphyseal junction, distal to the coronoid.
  • Type IIC: Purely diaphyseal ulnar fracture.
  • Type IID: Comminuted fractures spanning multiple regions.
• Type III: Features a lateral or anterolateral radial head dislocation with an ulnar metaphysis fracture. Often results from a direct blow to the inside of the elbow, with or without rotation.
• Type IV: An anterior radial head dislocation coupled with fractures of the proximal third of both the radius and ulna at the same level.

It's crucial to recognize "equivalent injuries" in adults. These are variable pathologies that may not always fit the traditional definition, as they might not present with a concomitant radiocapitellar dislocation. While they share similar mechanisms and treatment principles, we must acknowledge these distinctions.

Differential Diagnosis

When evaluating a potential Monteggia, always consider:

• Isolated ulna fracture: A "nightstick fracture" without radial head involvement.
• Fracture-dislocation of the elbow: Especially the "terrible triad" (radial head fracture, coronoid fracture, and elbow dislocation), which has a different pathomechanics and often requires a distinct surgical approach.
• Transolecranon fracture-dislocation.

Preoperative Planning: The Blueprint for Success

Effective preoperative planning is paramount. We must define all injuries requiring intervention and meticulously prepare our equipment and approach.

Imaging and Diagnostic Studies

Our initial assessment relies heavily on imaging:

• Plain Radiographs: Orthogonal radiographs of the entire elbow, forearm, and wrist are absolutely essential. We need to visualize the radiocapitellar joint, the entire ulna, and the distal radioulnar joint (DRUJ) to rule out concomitant injuries. Pay close attention to the relationship between the radial head and the capitellum. A subtle dislocation can be easily missed.
  

  
  
  

FIG 1 • Plain AP radiograph typically demonstrates fracture pattern.

Patient History and Physical Findings

A thorough initial examination is critical:

• Skin integrity: Assess for open fractures, abrasions, or impending skin compromise. The timing of surgery often depends on the soft tissue envelope.
• Neurovascular status: Meticulously check median, ulnar, and radial nerve function, as well as radial and ulnar pulses. Document any deficits preoperatively.
• Bony injury: Palpate for tenderness, crepitus, and gross deformity.
• Injury pattern: Characterize the ulna fracture (noncomminuted vs. comminuted, involvement of coronoid/olecranon) and radial head injury (isolated dislocation, fracture-dislocation, or radial head/neck fracture). Remember, a radial head dislocation can spontaneously reduce, making it subtle, so always maintain a high index of suspicion.

Equipment Requirements

Ensure all necessary equipment is available and templated:

• Fluoroscopy: Essential for intraoperative assessment of reduction and hardware placement.
• Bone graft: Allograft or autograft, readily available for areas of comminution or bone loss, especially for the ulna or radial head.
• Plating systems:
  • Small fragment plates and screws (2.7mm, 3.5mm) or an anatomic plating system for the ulna. We need plates contoured for the dorsal or subcutaneous border, depending on the fracture.
  • Minifragment systems for reconstructable radial head fractures.
• Threaded Kirschner wires (K-wires): For provisional fixation of both ulna and radial head fragments.
• Radial head replacement prostheses: Various sizes must be available if the radial head is unreconstructable.

Patient Positioning

We generally prefer the lateral decubitus position for Monteggia fractures.

1. Setup: The patient is positioned laterally, with the injured arm draped over a well-padded arm support.
   

   
   
   

FIG 2 • Lateral decubitus positioning is preferred.
2. Rationale: This provides excellent access to the posterior aspect of the elbow and forearm, allows for easy manipulation of the limb, and facilitates fluoroscopic imaging in both AP and lateral planes without repositioning the C-arm excessively.
3. Alternative: Supine positioning is an alternative, but it's less preferred due to the difficulty in maintaining the arm across the chest for exposure. If supine, a saline bag or a small bump under the ipsilateral shoulder can help keep the arm in a neutral adducted position, allowing it to rest across the chest. However, it often compromises access and makes fluoroscopy more challenging.

Preoperative Antibiotics and Tourniquet

• Administer broad-spectrum intravenous antibiotics (e.g., Cefazolin) within 60 minutes prior to incision.
• Apply a pneumatic tourniquet to the upper arm. We will inflate it after exsanguination to maintain a bloodless field, which is critical for identifying neurovascular structures and achieving precise reduction.

Surgical Approach: Exposing the Injury

Our primary approach will be a posterior midline incision, allowing versatile access to both the ulna and radial head.

Incision and Superficial Dissection

1. Skin Incision: Identify the tip of the olecranon. We will place a midline posterior skin incision, slightly lateral to the tip of the olecranon, extending proximally and distally as needed to adequately expose the ulnar fracture and radial head.
   

   
   
   

TECH FIG 1 • A. Posterior midline incision positioned just off the lateral aspect of the olecranon.
* Pearl: Positioning the incision slightly lateral minimizes the risk of direct pressure on the ulnar nerve postoperatively and avoids placing the scar directly over the subcutaneous border of the ulna, which can be irritating with hardware.
2. Subcutaneous Flaps: Using sharp dissection with a scalpel (e.g., #10 blade) and careful electrocautery for hemostasis, elevate full-thickness subcutaneous flaps medially and laterally.
* Anatomy Pearl: As we elevate the medial skin flap, be mindful of the medial antebrachial cutaneous nerve. This nerve typically runs superficially and can be mobilized with the medial skin flap if dissection is kept strictly on the fascia of the flexor-pronator muscles. Avoid aggressive undermining to protect this sensory nerve. Laterally, the posterior cutaneous nerve of the forearm (a branch of the radial nerve) may be encountered; gentle retraction is key.
* Warning:
> Surgical Warning: Excessive or careless electrocautery in the subcutaneous plane can damage superficial nerves, leading to persistent dysesthesias. Use a bipolar cautery for fine hemostasis around nerves.

Deep Dissection: Internervous Planes

Now, we'll develop our deep surgical interval to expose the fracture site.

1. Identify Landmarks: Palpate the subcutaneous border of the ulna. Medially, identify the robust fascia of the flexor carpi ulnaris (FCU) muscle. Laterally, locate the anconeus muscle, which originates from the lateral epicondyle of the humerus and inserts onto the lateral surface of the olecranon and proximal ulna.
2. Develop the Interval: The internervous plane we utilize is between the flexor carpi ulnaris (FCU) medially and the anconeus muscle laterally.
   • Anatomy Pearl: The FCU is innervated by the ulnar nerve, while the anconeus is innervated by the radial nerve (via its deep branch, the posterior interosseous nerve). This internervous plane allows us to access the ulna without violating muscle bellies or major neurovascular structures.
   • Carefully incise the deep fascia along the subcutaneous border of the ulna. Using blunt dissection with scissors (e.g., Metzenbaum) or a Cobb elevator, gently separate the FCU from the anconeus, reflecting them to expose the ulnar shaft and fracture fragments.
     

     
     
     

TECH FIG 1 • B. Deep surgical interval uses the internervous plane between the anconeus and flexor carpi ulnaris.
3. Extent of Exposure: The amount of dissection required is dictated by the specific fracture pattern and the type of fixation we plan to use. For a simple diaphyseal fracture, minimal exposure may suffice. For comminuted fractures or those extending proximally, more extensive subperiosteal elevation may be necessary.

Accessing the Radial Head (If Needed)

If the radial head needs surgical attention (e.g., for a reconstructable fracture or replacement), we can extend our exposure:

• Boyd Approach Modification: The anconeus muscle can be mobilized more extensively. We can release the anconeus from its origin on the lateral epicondyle of the humerus and reflect it proximally. This provides excellent exposure to the radial head and neck.
  

  
  
  

TECH FIG 1 • C. Exposure of the radial head can be accomplished by releasing the anconeus from the humerus and reflecting it proximally to expose the radial head.
* Anatomy Pearl: This maneuver exposes the capsule of the elbow joint and allows direct visualization of the radial head. Be mindful of the posterior interosseous nerve (PIN), which typically passes anteriorly around the radial neck and can be at risk with aggressive dissection or hardware placement in this area. Keep dissection close to bone, and avoid stripping the supinator too aggressively.

Radial Head Management: First Principles

The general principle for Monteggia injuries is to address the radial head before definitive fixation of the ulna. The rationale is that once the ulna is rigidly fixed, access to the radial head becomes significantly more difficult, if not impossible, through the same incision.

• Exception: If the lesser sigmoid notch of the ulna is involved, determining appropriate radial length for a radial head replacement can be challenging before ulnar reduction. In such cases, provisional ulnar fixation to restore length may be necessary before final radial head sizing and replacement. However, reconstructable radial head fractures are almost always fixed first.

Reconstructable Radial Head Fractures

1. Exposure: Through the extended posterior approach (Boyd modification), we gain direct visualization of the radial head fracture.
2. Reduction: Using small-pointed reduction clamps or K-wire joysticks, meticulously reduce the fracture fragments. The goal is an anatomic reduction of the articular surface.
3. Provisional Fixation: Secure the reduced fragments with 0.045" or 0.062" K-wires.
4. Definitive Fixation: Apply minifragment screws (e.g., 2.0mm or 2.4mm) or specialized radial head plates. Ensure all hardware is countersunk and does not impinge on the capitellum or ulna during forearm rotation and elbow flexion/extension.
   

   
   
   

TECH FIG 2 • A,B. Preoperative and postoperative radiographs demonstrating open reduction and internal fixation of the radial head component of the Monteggia fracture.
* Pearl: After fixation, gently range the elbow and forearm through a full arc of motion to confirm stable fixation and absence of impingement. Use fluoroscopy to confirm concentric reduction of the radial head within the capitellum.

Unreconstructable Radial Head Fractures

If the radial head is severely comminuted, with significant articular damage, or if reduction proves impossible, replacement is indicated.

1. Excision: Carefully excise all unreconstructable fragments of the radial head.
2. Sizing: This is a critical step. We need to restore radial length and maintain appropriate tension in the interosseous membrane. Trial radial head prostheses are used to determine the correct size.
   • Technique: Insert a trial prosthesis and assess stability of the radiocapitellar joint and the DRUJ. The radial head should articulate smoothly with the capitellum, and the forearm should rotate freely without impingement or excessive laxity. If the ulna is still fractured, we may need to provisionally reduce the ulna to restore overall forearm length before final radial head sizing.
3. Implantation: Once the correct size is determined, implant the definitive radial head prosthesis. This typically involves preparing the radial neck, cementing the stem (if appropriate for the prosthesis type), and ensuring optimal head placement.
   

   
   
   

TECH FIG 2 • ( continued ) C. Postoperative radiograph of a Monteggia fracture in which the radial head fracture needed to be replaced.

Ulna Fracture Fixation: Restoring Stability and Length

With the radial head addressed, our focus shifts to the ulna. The stability of the radial head is directly dependent on the accurate reduction and stable fixation of the ulna.

No Articular Involvement of the Ulnohumeral Joint

For ulna fractures distal to the coronoid, where the articular surface of the olecranon or coronoid is not involved:

1. Reduction: The primary goal here is to restore ulnar length, axial alignment, and rotation. Apply longitudinal traction to the forearm to disengage fragments. Use reduction clamps (e.g., Verbrugge, pointed reduction clamps) to achieve anatomic reduction of the fracture fragments.
   • Pearl: Once the ulna is anatomically reduced and stable, the radial head should spontaneously reduce and remain concentric with the capitellum. This is the "Monteggia rule" in action. If the radial head remains dislocated after a perfect ulnar reduction, suspect soft tissue interposition or a concomitant ligamentous injury requiring further exploration.
2. Provisional Fixation: Secure the reduced fragments with K-wires.
3. Plate Application: We will use a dorsal plate for definitive fixation.
   • Plate Choice: Choose a pre-contoured locking plate or a conventional small fragment plate (e.g., 3.5mm LCP). The plate should be long enough to achieve adequate working length, typically 6-8 cortices proximal and distal to the fracture.
   • Plate Placement: The dorsal aspect of the ulna provides a strong tension band effect. Proximally, the plate needs to oppose the olecranon. This often requires a partial split of the triceps tendon longitudinally along its fibers to expose the dorsal surface of the olecranon and allow the plate to sit flush.
   • Alternative: Some surgeons prefer lateral plate placement to prevent hardware prominence, but the dorsal aspect is biomechanically superior for most ulnar shaft fractures.
4. Screw Insertion:
   • Lag Screws: If possible, insert lag screws through the plate or independently across oblique fracture lines to achieve interfragmentary compression.
   • Cortical/Locking Screws: Fill the remaining plate holes with cortical or locking screws, ensuring bicortical purchase.
5. Fluoroscopic Confirmation: Take AP and lateral fluoroscopic images to confirm anatomic reduction of the ulna, concentric reduction of the radial head, and optimal hardware placement.

Articular Involvement of the Ulnohumeral Joint

Fractures extending proximal to the coronoid, involving the articular surface, demand a more meticulous approach. The plate must typically be placed on the subcutaneous border of the ulna to accommodate the complex geometry of this region and avoid impingement.

1. Reconstruction Sequence: We reconstruct these fractures from distal to proximal.
   • Distal Fragments: Begin by fixing the most distal ulnar fragments. This may involve interfragmentary fixation with lag screws or provisional stabilization with intramedullary K-wires to establish initial length and alignment.
     

     
     
     

TECH FIG 3 • A. Monteggia fractures with articular involvement should be fixed distal to proximal. Fixation may require intramedullary Kirschner wires or interfragmentary fixation.
2. Coronoid Reconstruction: This is often the most challenging part.
* Exposure: Coronoid involvement with Monteggia often presents as a fracture extending distally into the volar cortex of the ulna, differing from the axial-plane patterns. Exposure can often be obtained through the olecranon fracture itself. If not, the FCU can be carefully elevated from the dorsal aspect of the ulna to visualize the coronoid.
* Reduction: Meticulously reduce the coronoid fragment(s).
* Fixation:
* Lag Screws: Larger fragments can be definitively fixed with antegrade lag screws inserted from the dorsal aspect of the ulna, aiming volarly into the coronoid. This requires careful trajectory planning to avoid joint penetration.
* Provisional Wires: Smaller fragments can be provisionally held with threaded K-wires and then definitively secured once the plate is applied to the dorsal aspect of the ulna, potentially capturing these fragments indirectly.
* Crucial Focus: Particular attention must be directed at the anatomic reconstruction of the articular surface of the coronoid and greater sigmoid notch. Even minor incongruity can lead to post-traumatic arthritis and instability.
3. Olecranon Fragment Fixation: The olecranon fragment, with its attached triceps, is the final piece of the puzzle.
* Rationale: If reduced too early, the pull of the triceps can obscure the reduction of the more distal and articular fragments.
* Reduction: Once the distal ulna and coronoid are stable, reduce the olecranon fragment. Apply traction and direct pressure to align it anatomically with the reconstructed distal ulna.
* Provisional Fixation: Provisionally hold the olecranon with medial and lateral K-wires.

Wound Closure

With stable fixation achieved, we proceed to wound closure.

1. Tourniquet Release and Hemostasis: Deflate the tourniquet. Meticulously achieve hemostasis using electrocautery and ligatures. A dry field is crucial to prevent hematoma formation, which can increase the risk of infection and stiffness.
2. Drain Placement: I prefer to place a small suction drain (e.g., 1/8-inch Penrose or a small Blake drain) in the subcutaneous tissues. This helps to evacuate any residual blood and prevents hematoma formation.
3. Deep Fascial Closure: Close the deep fascia between the FCU and anconeus with interrupted absorbable sutures (e.g., 0 or 1 Vicryl). This helps to re

Additional Intraoperative Imaging & Surgical Steps

REFERENCES

1. Bado J. The Monteggia lesion. Clin Orthop Relat Res 1967;50:71.

2. Boyd H, Boals J. The Monteggia lesion: a review of 159 cases. Clin Orthop Relat Res 1969;66:94–100.

3. Bruce H, Harvey JJ, Wilson JJ. Monteggia fractures. J Bone Joint Surg Am 1974;56A:1563–1576.

4. Jupiter JB, Leibovic SJ, Ribbans W, et al. The posterior Monteggia lesion. J Orthop Trauma 1991;5:395–402.

5. Konrad GG, Kundel K, Kreuz PC, et al. Monteggia fractures in adults: long-term results and prognostic factors. J Bone Joint Surg Br 2007;89B:354–360.

6. Monteggia GB. Instituzioni Chirurgiche. 2nd ed. Milan: G. Masperp, 1813–1815.

7. Reckling F. Unstable fracture-dislocations of the forearm (Monteggia and Galeazzi lesions). J Bone Joint Surg Am 1982;64A:857–863.

8. Reckling FW, Cordell LD. Unstable fracture-dislocations of the forearm: the Monteggia and Galeazzi lesions. Arch Surg 1968;96:999– 1007.

9. Regan W, Morrey B. Fractures of the coronoid process of the ulna. J Bone Joint Surg Am 1989;71A:1348–1354.

10. Reynders P, De Groote W, Rondia J, et al. Monteggia lesions in adults: a multicenter Bota study. Acta Orthop Belg 1996;62(Suppl 1):78–83.

11. Speed J, Boyd H. Treatment of fractures of ulna with dislocation of the head of radius (Monteggia fracture). JAMA 1940;115:1699–1705.

12. Bado type II injury

13. Jupiter type IIa injury

14. Fracture of the radial head

15. Coronoid fracture

16. Complications requiring further surgery

COMPLICATIONS
- Complications associated with Monteggia fracture-dislocations occur with frequency. A multicenter study evaluating Monteggia fracture-dislocations in adults demonstrated complications in 43% of the patients treated, with an unsatisfactory outcome in 46% of the patients treated. 10

• Radial nerve palsy

• Most commonly posterior interosseous nerve

• Causes of injury include:

• Compression at the arcade of Frosche

• Direct trauma

• Traction with lateral displacement of the radial head

• Most common with type III fractures

• Complete resolution typically occurs.

• Malunion

• Most common in type II fractures with volar comminution that is not appreciated or addressed

• If radial head subluxation persists, malunion must be considered.

• Causes of nonunion include:

• Infection

• Inadequate internal fixation

• Compression plate fixation required, particularly if fracture is comminuted

• Semitubular and reconstruction plates are not structurally strong enough.

• Seen with high-energy injuries with associated comminution

• Higher incidence if radial head fracture associated with ulna fracture at the same level

• Boyd approach implicated since the radius and ulna are exposed through the same incision