Medical Imaging Analysis Report

I. Imaging Findings

The patient is a 31-year-old female, presenting with right knee pain that worsens with walking. There is no obvious history of trauma, but the posterior drawer sign is positive. Follow-up MRI (Magnetic Resonance Imaging) was performed, and after rest, local ice application, and pain medication, the pain subsided. Based on the provided MRI images and descriptions:

• On the mid-sagittal sequence of the knee, the posterior cruciate ligament (PCL) appears abnormal or thin, with atypical signals in some areas, suggesting possible congenital hypoplasia or deficiency of the structure.
• No apparent traumatic fracture was observed on the tibial spine. The contour is relatively flat, which may be related to the lack of tensile stress from a normal ligament.
• No obvious swelling or effusion signals were seen in the joint capsule or surrounding soft tissues.
• No significant fractures or abnormal signals were noted in the femoral condyle or tibial plateau. The articular surfaces appear generally smooth.

II. Potential Diagnoses

Taking into account the absence of significant trauma history, positive posterior drawer sign, and MRI findings, the main considerations are as follows:

1. Congenital PCL Hypoplasia/Deficiency
   Due to congenital factors leading to partial or complete absence of the posterior cruciate ligament, often accompanied by developmental abnormalities of adjacent bony structures (e.g., low-lying tibial spine). Clinically, this may present with a positive posterior drawer test or mild knee instability.
2. Chronic PCL Injury
   Although the patient has no obvious trauma history, prior minor injuries that were insufficiently addressed could lead to partial ligament tears or poor healing. A more detailed history of sports or physical examination findings might be necessary.
3. Other Knee Structural Abnormalities
   For example, posterior capsule or meniscal abnormalities. However, there is no obvious meniscal lesion on imaging, so these can be considered differential diagnoses.

III. Most Likely Final Diagnosis

After ruling out traumatic PCL rupture and other common ligament pathologies, considering congenital features, the abnormal ligament morphology on MRI, and the positive posterior drawer sign, the most likely diagnosis is “Congenital Posterior Cruciate Ligament Hypoplasia/Deficiency.”

If the patient continues to experience knee instability, recurrent pain, or other symptoms in the future, further imaging (e.g., high-resolution MRI or arthroscopic evaluation) may be indicated to clarify the extent of the deficiency and any associated abnormalities.

IV. Treatment Plan and Rehabilitation

For patients with congenital PCL hypoplasia who have relatively mild symptoms and retained range of motion, conservative management and targeted rehabilitation exercises can be attempted first. If there is significant instability, recurrent pain, or functional impairment, surgical reconstruction may be considered.

1. Conservative Treatment

• Joint Protection: Reduce high-intensity, prolonged weight-bearing activities, and avoid repeated deep knee flexion.
• Medication: Use NSAIDs (non-steroidal anti-inflammatory drugs) or oral analgesics during acute pain phases, with the aim of short-term use only.
• Physical Therapy: Local ice or heat application (depending on joint reaction), and modalities such as ultrasound or light therapy to help relieve pain and reduce inflammation.

2. Rehabilitation/Exercise Prescription

Designed according to the FITT-VP principle (Frequency, Intensity, Time, Type, and Progression):

• Frequency (F): Rehabilitation exercises 3–4 times per week, adjustable according to pain and joint tolerance.
• Intensity (I): Start with low-resistance or isometric training (e.g., straight leg raises, quadriceps isometric contractions), then gradually increase intensity after pain subsides and consider adding resistance bands or light weights.
• Time (T): Each session can be 15–30 minutes. Sessions can be split up according to individual recovery.
• Type (T):
  • Core and Lower Limb Strength Training: Strengthening quadriceps, hamstrings, etc., to enhance dynamic knee stability.
  • Balance and Proprioception Exercises: Single-leg stance, balance board training, and other exercises to improve joint stability.
  • Low-Impact Aerobic Activities: Swimming or cycling, which place less stress on the joint.
• Progression (VP): Gradually increase the difficulty and duration, and if necessary, conduct more advanced flexion-extension and proprioception training under professional supervision.

If the patient has other comorbidities (e.g., osteoporosis, cardiopulmonary issues), the intensity of exercise should be reduced, and exercise response should be closely monitored.

Disclaimer

This report is a reference analysis based on the current imaging and clinical history. It does not replace face-to-face medical diagnosis or professional medical advice. Patients should incorporate clinical findings and physicians’ recommendations to finalize their treatment and rehabilitation plan.