Differential Diagnosis for Lateral Knee Pain Worse with Squatting
- Single most likely diagnosis
- Iliotibial (IT) band syndrome: This condition is characterized by inflammation of the iliotibial band, a ligament that runs down the outside of the thigh from the hip to the knee. The IT band crosses over the lateral femoral condyle, and when it becomes inflamed, it can cause lateral knee pain, especially when squatting or running downhill. The repetitive friction of the IT band over the lateral femoral condyle during these activities exacerbates the pain.
- Other Likely diagnoses
- Lateral meniscal tear: A tear in the lateral meniscus, which is the cartilage structure in the knee joint, can cause lateral knee pain. Squatting can worsen the pain due to increased pressure on the meniscus.
- Lateral collateral ligament (LCL) sprain: An injury to the LCL, which connects the femur to the fibula, can cause lateral knee pain. Squatting can put additional stress on this ligament, exacerbating the pain.
- Popliteus tendonitis: Inflammation of the popliteus tendon, which is located at the back of the knee, can cause lateral knee pain. Activities like squatting can irritate the tendon, worsening the pain.
- Do Not Miss diagnoses
- Osteonecrosis of the femoral condyle: This condition involves the death of bone tissue due to a lack of blood supply. It can cause severe knee pain, especially with weight-bearing activities like squatting. Although less common, missing this diagnosis could lead to significant morbidity.
- Stress fracture: A fracture in one of the bones around the knee, such as the femur or tibia, can cause pain that worsens with activity. While less likely, a stress fracture is a critical diagnosis not to miss due to the potential for further injury if not properly treated.
- Rare diagnoses
- Peroneal nerve compression: Compression of the peroneal nerve, which runs down the outside of the knee, can cause pain, numbness, and weakness in the area. This is a less common cause of lateral knee pain but should be considered in the differential diagnosis.
- Synovial chondromatosis: A rare condition characterized by the growth of cartilage in the synovial membrane of the knee joint. It can cause knee pain and locking, and while rare, it's an important consideration in patients with unexplained knee pain.