Differential Diagnosis for Knee Pain with Pressure over the Lateral Femoral Condyle during Passive Flexion
- Single Most Likely Diagnosis
- Iliotibial (IT) Band Syndrome: This condition is characterized by pain and swelling on the lateral aspect of the knee, typically caused by friction of the iliotibial band over the lateral femoral condyle during flexion and extension of the knee. The symptoms described match closely with the presentation of IT band syndrome, making it the most likely diagnosis.
- Other Likely Diagnoses
- Lateral Meniscal Tear: Tears in the lateral meniscus can cause pain on the lateral side of the knee, especially with twisting or bending movements. The pain might be exacerbated by pressure over the lateral femoral condyle during passive flexion.
- Lateral Collateral Ligament (LCL) Sprain: An injury to the LCL can cause lateral knee pain, which might be worsened by varus stress or pressure over the lateral aspect of the knee.
- Do Not Miss Diagnoses
- Osteonecrosis of the Femoral Condyle: Although less common, osteonecrosis (avascular necrosis) of the femoral condyle can present with knee pain that worsens with weight-bearing activities or specific movements. Missing this diagnosis could lead to significant morbidity due to potential collapse of the bone.
- Infection (Septic Arthritis or Osteomyelitis): Infections within the knee joint or the bone itself are medical emergencies. While they might present with more systemic symptoms like fever and redness, localized pain and tenderness could be the initial complaint, making them crucial not to miss.
- Rare Diagnoses
- Synovial Chondromatosis: A rare condition where cartilage grows within the synovium of the joint, potentially causing pain, swelling, and mechanical symptoms. It could lead to lateral knee pain if the cartilaginous nodules are located in a way that they impinge on the lateral femoral condyle during movement.
- Ganglion Cyst: Although more common on the dorsal aspect of the wrist, ganglion cysts can occur around the knee and cause localized pain and pressure symptoms, especially if they are located near the lateral femoral condyle.