Monteggia injury is an ulnar fracture or traumatic anterior bowing associated with proximal radioulnar joint (PRUJ) and radiocapitellar joint dislocation.1,2 (Fig. 1) Monteggia lesions comprise approximately 1% of all pediatric forearm injuries, typically affecting children between the ages of 4 and 10 years. Since Giovanni Battista Monteggia’s original description in 1814, there have been great gains in the understanding of the pathoanatomy and treatment principles of these injuries. Nonetheless, Monteggia fracture-dislocations continue to be challenging injuries for the pediatric orthopaedic surgeon. In 1943, Sir Watson-Jones3 wrote, “… no fracture presents so many problems; no injury is beset with greater difficulty; no treatment characterized by more general failure”; much of these sentiments still apply in the treatment of acute and chronic Monteggia lesions today.
PRINCIPLES OF MANAGEMENT
Patients will typically present with pain, deformity, and limited elbow and/or forearm motion after fall onto an outstretched upper limb. Often, however, clinical signs and symptoms may be subtle, particularly in the younger child with incomplete fractures or plastic deformation of the ulna. Careful inspection, palpation, and assessment of elbow and forearm motion should always be part of the initial evaluation of the acutely injured pediatric upper limb.
Radiographic evaluation should include orthogonal plain films of the entire forearm, including the wrist and the elbow joints. Although greenstick and bicortical fractures of the ulna are readily apparent, systematic radiographic review should also include assessment of the PRUJ and the radiocapitellar joint. Normally, the longitudinal axis of the radius should bisect the capitellar ossification center on all views if the radiocapitellar joint is congruently reduced. Deviations from these normal radiographic relationships should alert the treating provider to the presence of a Monteggia lesion.
Monteggia injuries associated with plastic deformation (or traumatic bowing) of the ulna may be more subtle. Lincoln and Mubarak4 have previously described the “ulnar bow sign” in their assessment of subtle, posttraumatic radial head dislocations. If a straight dorsal ulnar border is not seen, there should be heightened suspicion for a plastic deformation injury to the ulna.
A host of classification systems have been proposed to aid in communication and guide treatment. Bado1 is credited with a radiographic classification system based on the direction of radial head dislocation and apex of the ulnar angular deformity. Bado type I injuries, in which the radial head dislocates anteriorly, is most common and comprises approximately 70% to 75% of pediatric Monteggia lesions. However, unlike adults, the second most common pattern in children is the Bado type III injury, in which the radial head dislocates laterally.
Letts et al5 proposed an alternative classification system, based on the pattern of ulna fracture. Ulna fractures are categorized as plastic deformation, incomplete (or “greenstick”), or complete, with additional information regarding the direction of displacement.
The treatment principles for the care of Monteggia injuries are well established. Ulnar length and alignment must be restored, which allows for congruent PRUJ and radiocapitellar reduction, and deforming forces should be counteracted.
Historically, the Bado classification has guided the nonoperative treatment of acute Monteggia lesions. In the typical Bado I deformity, for example, longitudinal traction, supination, and elbow flexion beyond 90 degrees have been advocated to achieve reduction and counteract the deforming influence of the biceps. However, there are challenges in the nonoperative care of acute Monteggia fracture-dislocations. Skilled manipulation and cast application is required. Serial radiographs must be obtained to ascertain maintenance of alignment—particularly challenging in type III fractures due to difficulties in radiographic visualization of the elbow in the coronal plane. Hyperflexion of the acutely injured and swollen elbow raises concerns for potential neurovascular compromise. Finally and most importantly, most historic literature suggests a loss of reduction rate in up to 20% of cases.6–8
To this end, Ring and Waters9 proposed a surgical treatment algorithm for acute Monteggia injuries based on the Letts classification and concepts of ulnar fracture stability (Table 1). Closed reduction and cast immobilization is recommended for plastic deformation and greenstick injuries, with careful serial radiographic checks to confirm maintenance of alignment. Patients with transverse or short oblique ulnar fractures have “length stable” injuries; in these patients, closed reduction and intramedullary fixation of the ulna will allow for maintained alignment and avoidance of lost reduction (Fig. 2). Conversely, patients with long oblique or comminuted fractures have complete but “length unstable” injuries and undergo reduction and internal fixation using appropriately sized plate-and-screw constructs (Fig. 3). A recent investigation of 112 acute Monteggia fractures treated at 2 tertiary-care children’s hospitals demonstrated that adherence to this surgical treatment algorithm lead to reliable bone healing, radiocapitellar reduction, and outstanding early clinical and radiographic results.8 In patients treated with less rigor than called for by the treatment algorithm, the loss of reduction rates were between 18% and 33%. On the basis of this information, surgical treatment should be strongly considered for acute Monteggia fracture-dislocations.
Despite awareness and well-intentioned treatment, chronic Monteggia lesions do occur. The original injuries may be missed in up to 33% of cases, and late loss of reduction following closed treatment can be seen in up to 20% of cases.6–8 Although the natural history of the chronic Monteggia lesion is not well characterized, some patients will present with pain, loss of motion (particularly flexion and supination), elbow deformity, late neuropathy, and even arthritis.
The reconstructive principles remain constant. Ulnar length and alignment must be restored to effectuate a congruent radiocapitellar reduction. Open reduction may be necessary to remove fibrous tissue and other soft tissue blocks to radial head reduction. Finally, annular ligament repair or reconstruction may be performed to provide additional stabilizers to the elbow joint. Indications for reconstruction include patients with pain or functionally limiting loss of elbow or forearm motion, in whom the concave morphology of the proximal radial head is preserved.
Ulnar correction may be performed using single-stage osteotomy or gradual distraction lengthening using external fixator or Ilizarov devices.10,12–15 The native annular ligament may still be present, although often displaced and fibrous tissue occluding the normal aperture through which the proximal radius normally resides.11 Careful PRUJ exposure and debridement may allow for identification, preservation, and dilation of the native ligament, which may then in turn be anatomically reduced around the radial neck. Alternatively, annular ligament reconstruction using triceps fascia, forearm fascia, or free tendon graft may be performed.16–18
Using an extensive posterolateral approach, the radial nerve may be identified in the brachialis-brachioradialis interval and carefully protected throughout the course of the procedure12 (Fig. 4). The radiocapitellar joint is open using a posterolateral (Kocher) approach in the anconeus-extensor carpi ulnaris interval, and the PRUJ is debrided with care to preserve the native annular ligament if possible. The site of ulnar deformity is identified, exposed, and osteotomized. Once the ulna is mobilized, the radial head may be congruently reduced; a temporary radiocapitellar smooth pin may be used to provide provision stability. As the radiocapitellar joint is reduced, the ulna will adopt the position of correction needed and is rigidly stabilized in situ using plate-and-screw constructs. Annular ligament repair or reconstruction is then performed. Stability is confirm intraoperatively by assessment of range-of-motion and fluoroscopy. Limited forearm fasciotomy may then be performed before wound closure to lessen the risk of postoperatively compartment syndrome.19
With these reconstructive principles and technical steps, improved elbow motion with maintained radiocapitellar reduction may be achieved in >80% of patients, with minimal complications and high satisfaction.
In summary, careful clinical and radiographic evaluation is needed in the acutely injured pediatric upper extremity to diagnose Monteggia fracture-dislocations. Acute surgical treatment according to the pattern of ulna fracture is safe and effective in maintaining reduction and optimizing clinical outcomes. In chronic Monteggia patients, sequential ulnar osteotomy, radiocapitellar reduction, with or without annular ligament repair or reconstruction, provides stable reduction and improved range-of-motion in the majority of cases.
1. Bado JL. The Monteggia
lesion. Clin Orthop Relat Res. 1967;50:71–86.
GB. Instituzioni Chirurgiches. [Surgical Institutes] Milan: Maspero; 1814.
3. Watson-Jones R. Fractures and Joint Injuries, 3r ed. Baltimore, MD: Williams & Wilkins; 1943;2.
4. Lincoln TL, Mubarak SJ. “Isolated” traumatic radial-head dislocation. J Pediatr Orthop. 1994;14:454–457.
5. Letts M, Locht R, Wiens J. Monteggia
fracture-dislocation in children
. J Bone Joint Surg Br. 1985;67:724–727.
6. Dormans JP, Rang M. The problem of Monteggia
fracture dislocations in children
. Orthop Clin North Am. 1990;21:251–256.
7. Fowles JV, Sliman N, Kassab MT. The Monteggia
lesion in children
. Fracture of the ulna and dislocation of the radial head. J Bone Joint Surg Am. 1983;65:1276–1282.
8. Ramski DE, Hennrikus WP, Bae DS, et al.. Pediatric Monteggia
fractures: a multicenter examination of treatment strategy and early clinical and radiographic results. J Pediatr Orthop. 2015;35:115–120.
9. Ring D, Waters PM. Operative fixation of Monteggia
fractures in children
. J Bone Joint Surg Br. 1996;78:734–739.
10. Inoue G, Shionoya K. Corrective ulnar osteotomy for malunited anterior Monteggia
lesions in children
. 12 patients followed for 1-12 years. Acta Orthop Scand. 1998;69:73–76.
11. Tan JW, Mu MZ, Liao GJ, et al.. Pathology of the annular ligament in paediatric Monteggia
fractures. Injury. 2008;39:451–455.
12. Bae DS, Waters PM. Surgical treatment of acute and chronic Monteggia
fracture-dislocations. Op Tech Orthop. 2005;15:308–314.
13. Degreef I, De Smet L. Missed radial head dislocations in children
associated with ulnar deformation: treatment by open reduction and ulnar osteotomy. J Orthop Trauma. 2004;18:375–378.
14. Exner GU. Missed chronic anterior Monteggia
lesion. Closed reduction by gradual lengthening and angulation of the ulna. J Bone Joint Surg Br. 2001;83:547–550.
15. Gyr BM, Stevens PM, Smith JT. Chronic Monteggia
fractures in children
: outcome after treatment with the Bell-Tawse procedure. J Pediatr Orthop B. 2004;13:402–406.
16. Bell Tawse AJ. The treatment of malunited anterior Monteggia
fractures in children
. J Bone Joint Surg Br. 1965;47:718–723.
17. Hui JH, Sulaiman AR, Lee HC, et al.. Open reduction and annular ligament reconstruction with fascia of the forearm in chronic Monteggia
lesions in children
. J Pediatr Orthop. 2005;25:501–506.
18. Seel MJ, Peterson HA. Management of chronic posttraumatic radial head dislocation
. J Pediatr Orthop. 1999;19:306–312.
19. Rodgers WB, Waters PM, Hall JE. Chronic Monteggia
lesions in children
. Complications and results of reconstruction. J Bone Joint Surg. 1996;78:1322–1329.