1. Radiological Findings

Based on the provided anteroposterior and lateral X-ray images of the forearm, it can be seen that there is a fusion or close contact between the proximal radius and ulna in the left forearm, suggesting an abnormal structure of the proximal radioulnar joint. Specific radiological features include:

• The proximal gap between the radius and ulna is narrowed or shows a bony bridge, indicating fusion.
• The distal forearm bony structure appears relatively normal, but overall the radius is mildly curved, and the ulna is relatively straight.
• No obvious acute fracture lines or bony defects are noted.
• No significant swelling or abnormal density changes are observed in the soft tissues.

2. Potential Diagnoses

Combining the patient’s history (limited forearm rotation noticed since age 6, no significant pain, and a paternal history of congenital upper limb deformity) and the radiological findings, the following potential diagnoses are considered:

1. Congenital Proximal Radioulnar Synostosis
   Reason: This condition is often familial and is commonly observed in school-age children. The radiographic finding of proximal fusion of the radius and ulna is a classic sign, and patients may have minimal pain but experience limited range of motion.
2. Post-traumatic Radioulnar Joint Fusion
   Reason: A long-standing history of trauma could lead to secondary fusion between the radius and ulna. However, neither the patient nor the family reports any history of trauma, and the symptoms have gradually been noted since childhood, making this possibility less likely.

3. Final Diagnosis

Taking into account the patient’s age, clinical presentation (restricted rotation with no pain), family history (father has a similar congenital deformity), and imaging findings, the most likely diagnosis is:

Congenital Proximal Radioulnar Synostosis.

4. Treatment Plan and Rehabilitation Program

For congenital proximal radioulnar synostosis, treatment strategies can be divided into conservative management and surgical intervention, chosen according to the patient’s functional requirements and the severity of the deformity.

1. Observation and Conservative Treatment
   • Indicated for patients with mild symptoms who can still manage daily activities. If forearm rotation limitations do not significantly affect daily life or sport activities, surgery may be postponed.
   • Daily functional exercises help to maintain joint flexibility and prevent disuse muscle atrophy.
2. Surgical Treatment
   • Indicated when there is a marked deformity or bilateral involvement significantly affecting daily activities.
   • Common surgical approaches include:
     • Excision of bony/fibrous fusion (Synostosis Excision) with soft tissue or artificial material interposition to reduce the chance of re-fusion. The improvement in forearm rotation is often limited.
     • Derotational Osteotomy of the forearm, fixing it in a more functional rotational position to improve independence and athletic performance.
   • Postoperative risks include the possibility of recurrent bony fusion, neurovascular injury, or compartment syndrome.

Rehabilitation and Exercise Prescription Recommendations:

• Preoperative or Conservative Phase:
  • The focus is on maintaining or improving muscle strength and joint range of motion. Daily sessions can include gentle forearm rotation (pronation-supination) exercises and wrist flexion-extension movements, preferably after warm compresses.
  • Perform exercises 3–5 times per week, gradually increasing frequency and duration based on the patient’s tolerance.
• Early Postoperative Phase (if surgery is performed):
  • Follow medical advice regarding immobilization and use of casts or splints to avoid excessive rotation or weight bearing.
  • Under the guidance of a rehabilitation therapist, begin gentle range-of-motion and muscle-strengthening exercises, closely monitoring for pain, swelling, or other concerns.
• Advanced Postoperative Rehabilitation:
  • Gradually increase active and passive range-of-motion exercises to build joint flexibility and muscle strength.
  • Incorporate low-intensity resistance training (e.g., using resistance bands) to enhance stability in the forearm, wrist, and hand muscles.
  • Perform exercises up to three times per week, adjusting intensity according to pain and fatigue levels, starting at 10 minutes per session and gradually increasing to 30 minutes.
• Long-Term Maintenance:
  • Continue functional exercises and follow-up based on the patient’s daily needs, monitoring bone growth and joint range of motion over time.

Disclaimer

This report is a reference analysis and cannot replace in-person consultation or professional medical advice. Treatment and rehabilitation plans should be carried out under the supervision of orthopedic specialists and rehabilitation physicians.