The patient was referred to an orthopaedic consultation because of an asymptomatic elbow deformity. The physical examination showed varus deformity of the forearm and limited flexion of the elbow. Additionally, she had multiples cutaneous “cafe-au-lait” skin spots (Fig.1). She was referred for an elbow and forearm X-ray.
AP (Fig. 2) and lateral (Fig. 3) X-ray of the right forearm showed an important anterolateral bowing of radial and ulnar diaphysis and significant resorption of the ulnar shaft at the junction of the middle and distal thirds, thought to have occurred after fracture. Radial head dislocation was also seen.
Neurofibromatosis type 1 (NF1), one of the most common genetic diseases, is an autosomal-dominant disorder due to a mutation or deletion of the NF1 gene on chromosome 17. [1] Neurofibromin, the gene product, is important in skeletal development. [2] NF1 is characterized by the formation of neurofibromas and abnormalities related to mesodermal dysplasia and affects multiple organ systems. Skeletal abnormalities are seen in up to 50% of patients and nearly all parts of the skeleton and its surrounding soft tissues can be involved. [3]
Spinal deformities occur in up to one half of patients with NF1 and include dystrophic and nondystrophic vertebral body changes. Scoliosis is the most common osseous complication, affecting 21% of patients, and varies in severity from mild, nonprogressive forms to severe curvatures. [4]
Nonossifying fibromas are well-defined, expansile lucent lesions with sclerotic margins with a narrow transition zone, classically asymptomatic, occurring in the metaphysis of long bones and the presence of multiple lower extremity nonossifying fibromas should raise suspicion and prompt a careful search for other evidence of neurofibromatosis. [5]
The effects of mesodermal dysplasia and extrinsic pressure may result in deficient bone formation and bowing and pseudarthrosis - a false joint with abnormal movement at the site of fracture - of the bones of the extremities. [3] Pseudarthrosis of the tibia is well established in NF1 but ulnar and radial pseudarthrosis are rare.
Forearm pseudarthrosis are related to NF in the majority of cases. Isolated pseudarthrosis of the ulna is the most frequent deformity, followed by pseudarthrosis of the radius and both forearm bones. [6]
In cases of isolated ulnar pseudarthrosis, a luxation of the proximal radial epiphysis may occur when the ulnar deformity increases with time, as it is seen in our case.
Although our patient did not have familial history of NF1, the diagnosis was also suspected because of the “cafe-au-lait” spots in her skin.
The definitive diagnostic confirmation of NF was obtained from molecular genetic testing.
The treatment of congenital pseudarthrosis in NF1 is very problematic and carries a high risk of failure. A variety of therapeutic concepts exists - immobilization with plaster casts, interposition of spongiosa with or without internal fixation and vascularized fibula transfers. [7] However, orthopaedic treatment and management of pseudarthrosis are challenging and complications are common.
As she had no symptoms, the presented patient was not submitted to surgery.
Neurofibromatosis type 1
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Based on the provided forearm and elbow X-rays, the following main features are observed:
1. The right forearm shows a notable varus-like deformity, with abnormality in the ulna segment bone structure, suggesting a possible pseudarthrosis or nonunion.
2. Malalignment of the proximal and distal ulna near the elbow joint, possibly accompanied by radial head subluxation or lateral displacement.
3. Thinning or irregularities in the local cortical bone, indicating potential bone developmental abnormalities.
4. Taking into account the imaging findings and physical examination results (such as restricted forearm range of motion and “café-au-lait” spots on the skin), neurofibromatosis type 1 (NF1) related skeletal manifestations should be considered.
Combining the patient's medical history, physical examination, and radiographic findings, the possible diagnoses are as follows:
Given the distinctly visible deformity and the common skin findings of NF1, Neurofibromatosis Type 1 is the most likely diagnosis.
Based on the patient's clinical presentation (including multiple “café-au-lait” spots), radiographic findings (forearm ulna pseudarthrosis, radial head subluxation, and bone deformities), and genetic testing results, the diagnosis is confirmed as Neurofibromatosis Type 1 (NF1) with forearm pseudarthrosis.
Although congenital and NF1-related pseudarthrosis can be difficult to treat, patients without significant symptoms or functional limitations can be managed conservatively. If the deformity progresses or pain and functional impairment worsen over time, surgical intervention may be considered. Specific strategies include:
Rehabilitation and Exercise Prescription Recommendations:
Under protection with braces or professional supervision, and in the absence of significant pain or functional impairment, the following rehabilitation exercises can be initiated in a gradual manner:
If there is compromised bone strength, postural abnormalities, or neurological symptoms, exercises should be performed under the supervision of qualified rehabilitation personnel or physicians to avoid falls or secondary injuries.
Disclaimer: This report is a reference analysis based on the available information and imaging, and it does not substitute an in-person consultation or professional medical advice. If you have any further concerns, please consult a relevant specialist promptly.
Neurofibromatosis type 1
