Knee Joint X-Ray Examination Medical Analysis Report

I. Radiological Findings

Based on the patient’s lateral X-ray of the left knee joint, a small, round osseous density can be seen posterior to the lateral femoral condyle, corresponding to the lateral head of the gastrocnemius muscle. This osseous density shows clear contours, a normal relationship with the surrounding bone, and no evident fracture lines or localized bone destruction. These findings are consistent with the “fabella,” a sesamoid bone found in the lateral head of the gastrocnemius.

In addition, the overall shape of the knee joint’s bony structures is essentially normal, the joint space is still acceptable, and there are no obvious signs of bone defects or significant soft tissue swelling.

II. Potential Diagnoses

1. Fabella: A sesamoid bone within the tendon of the lateral head of the gastrocnemius, commonly seen as an anatomical variant. It can be observed on routine lateral knee X-ray images.
2. Loose body or subchondral fracture fragments: If the nature of this density is unknown, it could be mistaken for an intra-articular loose body. However, its typical location and uniform density are more consistent with a fabella.
3. Traumatic avulsion fracture fragment: In the presence of a history of knee trauma, avulsion fracture should be ruled out. However, the image shows a smooth contour, without irregular bone cortex or fracture lines, making this diagnosis less likely.

III. Final Diagnosis

Taking into account the patient’s age, history of trauma, and imaging findings, the most likely diagnosis is: Fabella (a sesamoid bone at the lateral head attachment of the left gastrocnemius), with no obvious abnormality.

This type of sesamoid bone is typically a normal anatomical variant and usually does not require special treatment unless it is associated with pain, inflammation, or fracture-related complications.

IV. Treatment Plan and Rehabilitation

Given that the current imaging findings suggest a normal variant fabella, if the patient experiences no marked discomfort or pain, generally no special intervention is required. However, as there is a history of knee trauma, attention should be paid to maintaining knee joint stability and monitoring soft tissue condition to prevent secondary injury:

1. Conservative Management and Observation

• If there is no significant pain or functional impairment, simple observation and periodic follow-up may be sufficient.
• If mild discomfort is present, non-steroidal anti-inflammatory drugs (NSAIDs) can be considered to relieve pain and inflammation.
• Appropriate local icing and adequate rest are encouraged to help reduce any soft tissue swelling or pain that may occur after trauma.

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

• Frequency (F): Perform knee joint rehabilitation exercises 3–5 times per week.
• Intensity (I): Begin with low intensity and gradually increase as tolerated, based on pain level and joint stability. Start with low-load isometric and isotonic exercises, and progress to higher-intensity strength training.
• Time (T): Around 20–30 minutes per session, guided by any discomfort or fatigue in the joint. Avoid overexertion.
• Type (T): In the early phase, focus on simple range-of-motion exercises (such as straight leg raises, seated knee extensions, and flexion exercises), along with core strengthening. As stability improves, add closed-chain exercises like partial squats and balance training.
• Progression (P): As knee function recovers, slowly increase the load and intensity, for example by incorporating resistance bands or light weights. Monitor the joint response—if pain or swelling worsens, adjust the training accordingly.

For a 20-year-old patient without other structural injuries to the knee joint, overall rehabilitation prognosis is favorable. Should persistent swelling or pain occur during exercise, prompt medical review is recommended.

V. Disclaimer

This report is a reference analysis based on the imaging and clinical information currently provided and does not replace in-person clinical visits or professional medical consultations. In the event of persistent or worsening symptoms, it is recommended to seek further examinations and specialized medical advice.