1. Imaging Findings

Based on the provided anteroposterior radiograph of the pelvis, the following findings were observed:

• On the iliac surfaces of both sacroiliac joints, there are symmetrical, triangular areas of sclerosis with relatively well-defined margins.
• No obvious joint space narrowing can be seen, and no remarkable sclerosis is noted on the sacral side.
• No evident bone destruction or soft tissue swelling is observed.

These findings indicate symmetrical sclerotic changes on the iliac side of the sacroiliac joints, consistent with the typical imaging features of “Osteitis Condensans Ilii”.

2. Possible Diagnoses

• Osteitis Condensans Ilii (Sclerosis of the Iliac Side of the Sacroiliac Joint)

・Commonly seen in women of childbearing age or those with multiple pregnancies, potentially related to stress changes in the pelvis during pregnancy and childbirth.
・Typical radiographic manifestation is symmetrical lower iliac sclerosis with a normal or only mildly changed joint space.
・Most patients have no significant clinical symptoms, or only mild lumbosacral pain.

• Sacroiliitis (e.g., associated with Ankylosing Spondylitis or other inflammatory arthritis)

・Often presents with joint space narrowing, irregularities, or even erosions on the sacroiliac joints.
・May present with inflammatory back pain, often accompanied by elevated serologic or other inflammatory markers.
・In this case, there is no evident narrowing of the joint space or erosive changes, making this diagnosis less likely.

3. Final Diagnosis

Considering the patient’s gender, age, parity history, clinical symptoms, and imaging findings, the most likely diagnosis is: Osteitis Condensans Ilii.

In most cases, this condition has a good prognosis and can be self-limiting. If the patient experiences worsening pain or possible inflammatory symptoms in the future, serologic tests (e.g., ESR, CRP) and further imaging (e.g., MRI) may be considered to rule out sacroiliitis.

4. Treatment Plan and Rehabilitation

Overview of Treatment Strategies:

• Conservative Treatment: For patients with mild symptoms, observation and symptomatic management may be sufficient. Nonsteroidal anti-inflammatory drugs (NSAIDs) can help alleviate pain; temporarily reducing high-impact activities during acute episodes may also be beneficial.
• Physical Therapy and Postural Adjustment: Physical therapy (heat therapy, ultrasound, etc.) can alleviate pain and muscle tension. Attention should be paid to postnatal or daily positioning to avoid prolonged static postures.
• Surgical Intervention: Surgery is rarely required for this condition and is only considered in severe cases or when other structural abnormalities are present.

Rehabilitation and Exercise Prescription (Using the FITT-VP Principle):

• Type of Exercise (Type): Focus on exercises that strengthen the lumbar and pelvic stability, combined with low-impact aerobic activities (e.g., swimming, elliptical trainer, walking).
• Frequency of Exercise (Frequency): 3–5 times per week, increasing gradually based on individual tolerance.
• Intensity of Exercise (Intensity): Start with low to moderate intensity (e.g., maintain heart rate at 50–60% of the maximum). Avoid heavy loading or large twisting motions initially; gradually progress to moderate-intensity workouts.
• Duration of Exercise (Time): Begin with 20–30 minutes per session and gradually extend to 30–45 minutes. Include proper cooldown and stretching after each session.
• Mode, Progression, and Volume (Volume & Progression): Emphasize comfort and safety. As symptoms improve and fitness increases, consider adding resistance bands or Pilates to training. Gradually extend exercise duration and increase loading if no significant discomfort is noted.

If severe pain or discomfort occurs during training, adjust the exercise program or seek medical evaluation. Patients at risk of further pelvic or lumbar injury or those with reduced bone density should progress under the guidance of a specialist or physical therapist.

5. Disclaimer

The above report is a reference-based analysis founded on existing information and does not replace in-person diagnosis or professional medical advice. For any questions or changes in symptoms, please consult a relevant specialist or visit a hospital for evaluation.