Medical Imaging Analysis Report

I. Imaging Findings

Based on the provided knee X-ray and MRI scans, the following observations are noted:

• X-ray: Slightly increased bone density is noted in the weight-bearing area of the medial femoral condyle; no obvious collapse or distinct disruption of trabecular bone is observed. No significant swelling is seen in the soft tissues.
• MRI (sagittal and coronal sequences): An abnormal signal is observed beneath the articular surface of the medial femoral condyle, appearing as low signal on T1WI and high signal on T2WI/PD, indicative of local bone marrow edema and a possible subchondral fracture line. Surrounding soft tissues also show some degree of edema signal. No obvious large-scale soft tissue or ligament tear is noted.
• The articular cartilage appears acceptable. Some sequences suggest degenerative or mild tear changes in the medial meniscus. Joint space narrowing is not significant, but mild osteoarthritic changes are suspected.

II. Potential Diagnoses

1. Spontaneous Osteonecrosis of the Knee (SONK)

   Commonly seen in older adults, especially women, often involving the weight-bearing region of the medial femoral condyle. It is characterized by bone marrow edema, subchondral fracture lines, and abnormal signals just beneath the joint surface, consistent with the findings here. Additionally, the patient has no history of trauma or long-term steroid use, matching the typical presentation of spontaneous osteonecrosis.

2. Subchondral Fracture / Stress Fracture

   Because the patient is older and female, bone quality may be relatively compromised. Long-term weight-bearing or minor overloading could induce a stress fracture. MRI findings of bone marrow edema and localized low-signal lines suggest the possibility of a stress reaction. Coexistence with spontaneous osteonecrosis cannot be ruled out and requires careful differentiation.

3. Osteoarthritis with Subchondral Fracture

   Older patients often have osteoarthritis. Joint cartilage wear may lead to stress concentration on the articular surface, potentially causing subchondral fracture. However, since there is no significant joint space narrowing or severe cartilage destruction in this case, the first two diagnoses are more likely.

III. Most Likely Final Diagnosis

Considering the patient’s age (67 years), sex (female), clinical presentation (chronic knee pain with no history of trauma), and imaging findings (bone marrow edema of the medial femoral condyle, low signal on T1WI, high signal on T2WI, and evidence of a subchondral fracture line), the most likely diagnosis is Spontaneous Osteonecrosis (SONK) accompanied by a subchondral or stress-related reaction.

IV. Treatment Plan and Rehabilitation

1. Conservative Treatment

   1) Reduced Weight-Bearing: Use crutches, a walker, or other aids to minimize prolonged high load on the knee joint and reduce the risk of further collapse.
   2) Pain Relief and Anti-Inflammation: Nonsteroidal anti-inflammatory drugs (NSAIDs) or other pain medications can be considered as needed. Local physical therapy may also help alleviate pain and edema.
   3) Intra-Articular Injection Therapy: If necessary, consider hyaluronic acid or platelet-rich plasma (PRP) injections to improve joint function and relieve pain (subject to specific patient conditions and institutional resources).

2. Surgical Intervention

   In cases where conservative management fails or severe collapse of the articular surface occurs, surgical procedures such as condyle reshaping or knee replacement may be necessary. However, in early or mid stages, conservative management, observation, and prevention are generally preferred.

3. Rehabilitation and Exercise Prescription (FITT-VP Principle)

   1) Frequency: Aim for 3–5 sessions per week, adjusting based on pain and fatigue levels.
   2) Intensity: Begin with low-intensity exercises, such as gentle joint movement, straight leg raises, or light resistance training. Reduce intensity or pause if significant pain occurs.
   3) Time: Start with 10–20 minutes per session and gradually increase up to 30 minutes, incorporating multiple rest periods to reduce joint stress.
   4) Type: Focus on non-weight-bearing or reduced-weight exercises, such as seated or supine hip flexor training, balance exercises, swimming, or aquatic activities to decrease direct load on the knee joint.
   5) Progression: Gradually add load or difficulty as symptoms and muscle strength improve, such as slow indoor cycling or seated knee extension/flexion workouts. Avoid staying at the same level indefinitely or overexerting suddenly.
   Note: If marked pain, joint swelling, or a decline in functional capacity occurs, decrease exercise volume or pause activities immediately and seek evaluation from a rehabilitation specialist or physician before continuing.

Disclaimer: This report serves as a referential analysis only and should not replace in-person medical evaluation or professional medical advice. For specific diagnosis and treatment plans, please consult orthopedic and rehabilitation specialists.