A 4-and-a-half-years-old boy presented to the casualty department with traumatic pain, swelling and inability to move his left forearm and elbow. The parents reported that the child fell on his left upper extremity. Examination revealed tenderness of the mid-forearm and around the elbow with restriction of active and passive movements. The neurovascular status was unremarkable. There were no other skeletal complaints.
Anterior-posterior radiograph of the left forearm revealed a spiral apex-lateral mid-shaft fracture ulna and an anterior dislocation of the radial head/metaphysis. It was uncertain if the proximal radial epiphysis/head was evident radiographically (Fig.1). Orthogonal views of the elbow revealed an anterior dislocation of the radial head/metaphysis. The intraoperative orthogonal views of the elbow confirmed the presence of the proximal radial epiphysis/head in its anatomic location and consequent relocation of the dislocated radial metaphysis (Fig.2a,b). Additional intraoperative and early postoperative views of the elbow showed satisfactory reduction and healing of the ulna fracture and anatomic relocation of the anteriorly dislocated proximal radial metaphysis. Shortly said, the proximal radial epiphysis/head was originally maintained its normal articulation with the capitellum, whilst the proximal radial metaphysis was dislocated through the physeal line i.e. transphyseal and not a typical joint dislocation (Fig.3,4). The morphological evolution of proximal radial epiphysis ossification is shown (Fig. 5).
Monteggia fracture-dislocations or lesions are described as a dislocation of the radial head – typically through the radio-capitellar joint – associated with a fracture of the ulna. The direction of radial head dislocation usually follows that of fracture angulation. Generally, acute Monteggia lesions that are properly and timely managed, fare satisfactorily with closed reduction [1]. Although acute Monteggia lesions are uncommon in children, misdiagnosis and consequent mismanagement are not uncommon and can lead to prolonged treatment periods and long-term sequelae [2-4].
The presence of abundant literature on the management of neglected/chronic Monteggia lesions in children indicates that there is a problem with interpreting the plain radiographs in the acute setting [2-5]. This is attributed to the variability in the timing and sequence of appearance of the secondary ossification nuclei around the elbow, the presence of normal anatomic variants that may simulate pathological lesions [6, 7] and the tendency of the child’s elbow to exhibit associated fractures [8-10]. The emergence of Monteggia variants or equivalents that do not literally fit the typical description of Monteggia lesions yet otherwise bare general resemblance to, adds to the radiographic challenges [8-10-13].
This report provides key messages as follows. The initial lateral forearm radiographs failed to capture the elbow (Fig. 1b). Relying solely on suboptimal forearm radiographs and/or failure to obtain elbow-centred radiographs can miss Monteggia lesions. The dislocation of the proximal radial occurred through the proximal radial physeal line and not through the radio-capitellar joint as in typical Monteggia lesions. The early radiographic signs of ossification of proximal radius epiphysis usually appear 4 years of age. In our report, failure to recognize the tiny ossification nucleus of the proximal radius epiphysis may have resulted in misdiagnosis of the emerging ossification nucleus as an entrapped intra-articular fragment or radiographic artefact. Such misinterpretation of radiographs may eventually lead to unnecessary investigations and treatment.
Teaching Points
Associated fractures e.g. radial neck in this report, should always be considered in pediatric elbow trauma.
Atypical transphyseal anterior Monteggia fracture-dislocation or Monteggia variant
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1. The forearm X-ray shows a fracture line in the midshaft of the ulna with displacement, and suboptimal alignment between the fracture fragments.
2. Near the elbow, especially around the proximal radius, there is an abnormal radiolucent line suggesting possible physeal or metaphyseal injury. Given the young patient’s age and the incomplete ossification of the radial head, one should be highly vigilant for a radial head subluxation or a separation involving the physis.
3. Local soft tissue swelling is noted, with increased soft tissue shadow around the fracture site, but no obvious signs of nerve or vascular impingement.
4. On the anteroposterior and lateral views of the elbow, the anatomical alignment between the radial head and the humeral capitellum appears abnormal, suggesting a “Monteggia”-type combined injury (ulnar fracture + radial head dislocation) or a variation thereof.
5. Further observation reveals discontinuity in the proximal radial cortex, raising suspicion of a concurrent radial neck fracture or a fracture/fissure near the proximal radioulnar joint.
Based on the child’s age, mechanism of injury, radiographic findings, and overall physeal development, the most likely diagnosis is: “Acute Monteggia Variant Fracture (Ulnar Fracture with Concomitant Proximal Radial Fracture/Dislocation)”, i.e., a fracture of the ulna coexisting with a possible fracture involving the radial epiphysis or neck (and potentially an atypical or variant radial head subluxation).
1. Treatment Strategy:
(1) Closed Reduction and Fixation:
- Perform manual closed reduction of the ulnar fracture to restore length and alignment, and stabilize it using a splint or an appropriate brace/cast designed for children.
- If there is concurrent proximal radial (radial head or neck) fracture/malalignment, closed reduction can also be attempted. If stability is achieved, treatment may consist of splint or cast immobilization.
(2) Surgical Treatment:
- If closed reduction does not achieve satisfactory alignment, or if there is severe physeal injury of the proximal radius, consider percutaneous Kirschner wire fixation or limited internal fixation to protect the physis and prevent long-term malunion.
(3) Radiographic Follow-up:
- Obtain regular X-ray follow-ups to evaluate fracture alignment, reduction, and physeal development. Further intervention is warranted if any displacement is discovered.
2. Rehabilitation / Exercise Prescription:
(1) Early Phase (Postoperative or 1–3 Weeks of Immobilization):
- Keep the affected limb non–weight-bearing and use appropriate external fixation (brace or cast).
- Avoid strenuous activity to prevent further trauma.
- Under medical supervision, perform gentle exercises for the fingers and the wrist to promote circulation and reduce swelling.
(2) Mid-Phase (3–6 Weeks):
- If the fracture is stable, gradually remove or replace the immobilization (based on healing status and physician’s advice), but continue to use protective bracing.
- Begin non–weight-bearing active range-of-motion exercises for the elbow (flexion and extension) and forearm (pronation and supination).
- Increase training frequency gradually (2–3 times per day, 5–10 minutes each session) according to the child’s tolerance.
(3) Late Phase (6 Weeks and Beyond):
- Once there is evidence of fracture healing, progressively increase weight-bearing and expand the range of motion of the affected limb.
- Incorporate detailed exercises, such as wringing a towel, lifting light objects, and practicing forearm pronation and supination.
- Continue regular follow-up to monitor bone growth and functional recovery. Seek medical attention if any pain or activity restriction arises.
During the rehabilitation process, please follow the principles of gradual progression and individualization according to the child’s skeletal and muscular development. Sudden increases in exercise intensity should be avoided. Monitor for signs of pain or swelling, and consult a physician promptly if any significant discomfort occurs.
This report is based on the current medical history and radiological findings and serves as a reference for medical analysis only. It is not intended as a definitive diagnosis or treatment prescription. A specific treatment plan and medication regimen should be determined through evaluation of clinical presentation, laboratory results, and professional in-person medical consultation. For any questions or changes in condition, please promptly seek advice from a specialist.
Atypical transphyseal anterior Monteggia fracture-dislocation or Monteggia variant
