般瑞医疗科技

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AI Report

Clinical History

Fixed pronated forearm.

Imaging Findings

The patient presented with a history of trauma over his left elbow joint. After the fall he complained of pain and swelling of the lateral aspect of his elbow. Examination revealed a fixed pronated forearm, and inability to supinate the forearm and the hand. Radiographs of the elbow showed an osseus fusion between the proximal ends of the radius and ulna, without evidence of fracture.

Discussion

Congenital radioulnar synostosis is a relatively uncommon deformity that involves the proximal end of the radius and ulna, and in which the proximal radioulnar joint space fails to form (1). The failure of longitudinal segmentation during the seventh week of development results in a persistent bridge of tissue that connects the proximal end of the radius to the neck of the ulna. Usually this tissue ossifies into an osseus synostosis, although fibrous synostosis can also occur. The synostosis is bilateral in over 60 percent of cases (2), affecting men and women equally or showing slight men predominance (3). The sporadical examples occur more often than familial cases (dominant inheritance) (3). Although most of cases have been isolated, additional anomalies may appear, such as congenital dislocation of the hip, club feet, anomalies of the knee joint, coalescence of the carpal bones, missing or diminutive thumb, symphalangism and Madelung´s deformity (4). The frequent association with other congenital syndromes such as Aperts, Williams, Klinefelter, Nievergelt-Pearlman, and acrocephalopolysyndactyly, supports the idea of the genetic origin (4). Depending of the extent of involvement, two types have been described:
- type I, proximal or true radioulnar synostosis, in which the radius and the ulna are smoothly fused at their proximal borders for a variable distance, usually 2-6 cm, and
- type II, secondary or radioulnar synostosis associated with congenital dislocation of the radial head, in which the fusion is just distal to the proximal radial epiphysis (1). In both types, interference with the ability to supinate the forearm is seen.

Differential Diagnosis List

Congenital proximal radioulnar synostosis type I

Final Diagnosis

Congenital proximal radioulnar synostosis type I

Liscense

Figures

Radiograph of the left elbow

Medical Imaging Analysis Report

1. Imaging Findings

In the provided proximal forearm X-ray images (AP and lateral views), there is a bony fusion observed between the proximal borders of the radius and ulna, with the proximal radioulnar joint space absent. The site of fusion appears relatively regular, with no obvious fracture lines or acute trauma signs. Due to the abnormal relationship between the radial head and the proximal ulna, the forearm is fixed in a pronated position.

The overall bone density is normal, with no evident osteoporosis or bone destruction.
The parallel alignment of the proximal radius and ulna is affected, and there is no normal separation between the radial head and the proximal ulna.
No marked soft tissue swelling or proliferative changes are observed, and no obvious free soft tissue density is noted.

2. Potential Diagnoses

Congenital Proximal Radioulnar Fusion (Congenital Radioulnar Joint Fusion)
Etiology: During the seventh week of embryonic development, the segmentation between the radius and ulna does not fully form, leading to a bony or fibrous bridge between the proximal radius and ulna.
Imaging Characteristics: Absence of the proximal radioulnar joint, often presenting with the forearm fixed in pronation; the length of the fused segment can vary.
Epidemiology: Can be unilateral or bilateral, and may occur sporadically or in a familial pattern.
Post-Traumatic Radioulnar Fusion
Etiology: Previous forearm fracture or surgical intervention may result in ossification or ectopic bone formation, leading to fusion of the radius and ulna.
Imaging Characteristics: Often associated with other signs of trauma or postoperative changes (e.g., fracture healing or retained internal fixation devices), and the fusion typically appears irregular.
Severe Degenerative or Inflammatory Joint Disease
Etiology: Conditions such as rheumatoid arthritis or severe degeneration can lead to local tissue destruction and bony ankylosis.
Imaging Characteristics: More commonly presents with irregular joint surface destruction, narrowing of the joint space, and potential subchondral sclerosis or erosive changes.

3. Final Diagnosis

Based on the patient’s age (48 years), clinical history (forearm fixed in pronation), and imaging findings (proximal radioulnar fusion, joint space disappearance, and no evident trauma or degenerative changes), the most likely diagnosis is:

Congenital Radioulnar Joint Fusion (Congenital Proximal Radioulnar Fusion, Type I or II)

If further clarification of the bony fusion extent and soft tissue structures is needed, CT or MRI can be considered for more detailed evaluation.

4. Treatment Plan and Rehabilitation

Treatment Strategy Overview:

Conservative Treatment: If the patient’s daily function is not severely limited, physical therapy and functional exercises can help maintain or improve joint mobility. Orthotic devices (such as braces) can be used to enhance the range of motion and overall quality of life.
Surgical Treatment: When functional impairment is significant and quality of life is severely affected, surgical options (e.g., osteotomy, release of the bony fusion, or joint replacement) may be considered. However, the surgical risks, bone quality, and long-term rehabilitation prospects need to be carefully evaluated.

Rehabilitation and Exercise Prescription:

Initial Rehabilitation Phase:
- Focus on low-intensity, short-duration exercises to avoid excessive stress on the fused area.
- Engage in gentle movements of the shoulder and wrist joints (such as shoulder flexion-extension, circumduction, and wrist flexion-extension).
- Limit each session to about 10–15 minutes, once or twice a day.
Gradual Progression Phase:
- Within tolerance, increase exercise frequency to 2–3 times per day, 15–20 minutes each time.
- Incorporate light resistance exercises, such as using a resistance band or small dumbbells to strengthen muscles around the shoulder and elbow. Avoid forceful forearm twisting.
- If pain or wrist discomfort occurs during training, reduce the intensity or pause the exercises.
Maintenance and Strengthening Phase:
- Gradually increase range of motion and training load according to the patient’s symptoms and rehabilitation outcomes.
- Utilize swimming or aquatic exercises to promote balanced muscle development around the joints and reduce the risk of further joint injury.
- Under the guidance of a rehabilitation professional, progressively increase exercise frequency to 3–5 times per week, about 30 minutes each session.
Individualization and Safety: Regular follow-up is recommended to monitor forearm and elbow joint mobility and muscle strength. If any acute pain, swelling, or sudden functional decline occurs, seek medical attention promptly.

5. Disclaimer

This report provides a reference analysis based on current imaging and clinical information and cannot replace an in-person consultation or professional medical opinion. For further diagnosis or treatment needs, please consult a specialized physician for evaluation and management.

Human Doctor Final Diagnosis

Congenital proximal radioulnar synostosis type I

AI Doctor