1. Imaging Findings

Based on the provided MRI images of the knee, the following observations are noted:
• There is a lobulated or fragment-like signal change at the inferior pole of the patella, with local signs of calcification or bony fragments, suggesting an abnormal bony appearance of the patellar inferior pole.
• Thickening and signal enhancement of the patellar tendon near its patellar attachment, suggesting stress-related changes or inflammation at the tendon insertion site.
• Localized edema signal in the Hoffa’s fat pad, indicating local soft tissue irritation or inflammatory changes.
• No obvious fracture lines or significant cartilage surface destruction are seen, and the joint space is generally preserved.
These changes are consistent with bone and soft tissue alterations caused by repeated traction at the inferior pole of the patella.

2. Potential Diagnoses

1. Sinding-Larsen-Johansson Syndrome
   Caused by repetitive jumping, pulling, or stress at the patellar inferior pole, leading to recurrent microtrauma and inflammation at the attachment site, commonly seen in adolescents. Imaging often shows irregular ossification and fragment-like changes at the inferior pole of the patella.
2. Osgood-Schlatter Disease
   Although this condition is more commonly seen at the tibial tubercle, it is also a traction apophysitis in growing individuals. If the imaging primarily shows changes at the inferior pole of the patella, Osgood-Schlatter is less likely but can be considered in differential diagnoses.
3. Patellar Tendinopathy or Patellar Tendonitis
   Chronic overuse can lead to degenerative changes or inflammation in the patellar tendon. Imaging typically shows tendon thickening and abnormal signals, but bone fragment formation is less common.
4. Avulsion Fracture of the Patellar Inferior Pole (Rare)
   Often accompanied by a clear history of acute trauma and fracture lines. Given a five-month history of chronic pain, this is less likely, but a rare chronic or incomplete avulsion should be ruled out.

3. Final Diagnosis

Considering the patient’s age (14-year-old adolescent), recurrent anterior knee pain, and MRI showing fragment-like changes at the inferior pole of the patella with soft tissue edema at the patellar tendon attachment, the most consistent clinical imaging diagnosis is Sinding-Larsen-Johansson Syndrome (traction apophysitis at the patellar inferior pole).

4. Treatment Plan and Rehabilitation Program

1. Conservative Treatment
   • Activity Modification: Avoid or reduce movements that cause pain, such as jumping, squatting, running, or climbing stairs. Use a knee brace or elastic bandage if necessary for local protection.
   • Physical Therapy: Ice or heat therapy to relieve local pain and swelling, supplemented by ultrasound therapy, infrared therapy, etc., to accelerate the resolution of inflammation.
   • Medication: Non-steroidal anti-inflammatory drugs (NSAIDs) can be used short-term during periods of severe pain to help reduce inflammation and discomfort.
2. Surgical Indication
   Surgery is rarely indicated for Sinding-Larsen-Johansson syndrome. It may be considered only in a small number of refractory cases where prolonged conservative treatment fails and there is a significant impact on function, involving debridement or repair procedures.
3. Rehabilitation / Exercise Prescription
   Following the “FITT-VP (Frequency, Intensity, Time, Type, Volume, Progression)” principle, the rehabilitation is phased as follows:
   
   • Early Stage (Acute Pain Phase)
     • Frequency: 1-2 sessions per day, mainly focused on physical therapy and static exercises (e.g., isometric contraction of the quadriceps).
     • Intensity: Low intensity, avoiding significant pain; gentle local massage and stretching to increase blood flow and maintain patellar tendon elasticity.
     • Time: 15-20 minutes per session, adjustable according to pain tolerance.
     • Type: Passive or light active exercises, combined with ice therapy or physical modalities.
     • Progression: Gradually increase stretching and quadriceps activation frequency and duration based on pain response.
     
   • Intermediate Stage (Pain Relief Phase)
     • Frequency: 3-4 times per week, with adequate rest.
     • Intensity: Gradually progress from low to moderate; may include resistance band training, integrating isometric-concentric exercises for the quadriceps.
     • Time: 20-30 minutes per session, incorporating stretching, warm-up, and coordination exercises.
     • Type: Emphasis on strengthening and flexibility of the patellar tendon, quadriceps, and hamstrings, along with balance exercises.
     • Progression: Increase loading or resistance incrementally if pain does not worsen.
     
   • Late Stage (Recovery and Reconditioning Phase)
     • Frequency: 3-5 times per week, integrating dynamic and functional exercises.
     • Intensity: Moderate to moderately high, gradually returning to partial or full weight-bearing activities.
     • Time: 30-40 minutes per session, possibly divided into segments (e.g., strength, flexibility, coordination, balance).
     • Type: Gradual progression to running and jumping drills, ensuring correct movement patterns and joint stability.
     • Progression: Increase loads and difficulty step by step according to individual response, avoiding premature or excessive impact.
     
   Throughout the rehabilitation process, training intensity and methods should be adjusted in accordance with the patient’s recovery assessment. If pain or symptoms recur, reduce or suspend activities and seek targeted treatment.

Disclaimer: This report is intended for academic and clinical reference only and should not substitute for an in-person consultation or professional medical advice. If you have any questions or if symptoms worsen, please see a physician promptly.