Differential Diagnosis for Atraumatic Knee Pain
Single Most Likely Diagnosis
- Patellofemoral Pain Syndrome (PFPS): This condition is characterized by pain around or behind the patella, often exacerbated by activities that put stress on the knee, such as walking, bending, or climbing stairs. The patient's age and symptoms align with PFPS, making it the most likely diagnosis.
Other Likely Diagnoses
- Meniscal Tear: Although the patient reports atraumatic knee pain, meniscal tears can occur without a significant traumatic event, especially in younger individuals. The pain worsens with activities like walking and bending, which could indicate a meniscal issue.
- Ligamentous Sprain: A mild ligamentous sprain could cause knee pain without a significant traumatic event, especially if the patient has recently increased their physical activity level.
- Osteochondritis Dissecans: This condition involves a fragment of cartilage and bone becoming detached from the surrounding bone, often causing pain that worsens with activity.
Do Not Miss Diagnoses
- Septic Arthritis: Although less likely, septic arthritis is a medical emergency that requires prompt diagnosis and treatment. The patient's symptoms could be indicative of an infectious process, especially if they have a fever or recent history of infection.
- Osteonecrosis: This condition involves the death of bone tissue due to a lack of blood supply, which can cause severe knee pain. It is essential to consider osteonecrosis, especially if the patient has a history of steroid use or other risk factors.
- Tumor: A bone or soft tissue tumor could cause knee pain, and although rare, it is crucial to consider this possibility to avoid delayed diagnosis.
Rare Diagnoses
- Plica Syndrome: This condition involves inflammation of the synovial folds within the knee joint, causing pain and stiffness. It is a rare cause of knee pain but should be considered if other diagnoses are ruled out.
- Synovial Chondromatosis: This condition involves the growth of cartilage nodules within the synovial membrane, causing knee pain and stiffness. It is a rare diagnosis but should be considered if other causes are excluded.