Differential Diagnosis for 7yo Male with Knee Pain
- Single most likely diagnosis
- Osgood-Schlatter disease: This condition is a common cause of knee pain in adolescents, particularly during periods of rapid growth. The pain is typically located at the tibial tubercle, which is the bony prominence just below the kneecap, and is exacerbated by activities that involve running, jumping, or quick changes of direction, such as soccer. The difficulty in achieving the last 20 degrees of flexion due to pain is also consistent with this diagnosis.
- Other Likely diagnoses
- Sinding-Larsen-Johansson syndrome: This condition is similar to Osgood-Schlatter disease but affects the patellar tendon at its origin on the inferior pole of the patella. It presents with pain and swelling below the kneecap, especially with activities that involve jumping or running.
- Patellar tendinopathy: Also known as jumper's knee, this condition involves inflammation of the patellar tendon, leading to pain and stiffness, particularly with activities that involve jumping or quick changes of direction.
- Medial plica syndrome: This condition involves irritation of the medial plica, a fold of synovial tissue in the knee. It can cause pain, especially with twisting or bending movements.
- Do Not Miss diagnoses
- Septic arthritis: Although less likely, septic arthritis is a medical emergency that requires prompt diagnosis and treatment. It presents with severe pain, swelling, redness, and warmth of the affected joint, and can lead to serious complications if not treated promptly.
- Osteosarcoma: This is a type of bone cancer that can present with pain, swelling, and limited range of motion. Although rare, it is crucial to consider this diagnosis to ensure timely treatment.
- Slipped capital femoral epiphysis (SCFE): This condition involves the displacement of the femoral head from the femoral neck through the physeal plate. It can present with pain in the knee, thigh, or groin, and is a medical emergency that requires prompt treatment.
- Rare diagnoses
- Discoid meniscus: This is a rare condition where the meniscus is thicker and more disc-like than normal. It can cause pain, snapping, or locking of the knee.
- Meniscal cyst: This is a rare condition where a cyst forms in the meniscus, causing pain, swelling, and limited range of motion.
- Popliteal cyst (Baker's cyst): This is a fluid-filled cyst that forms in the back of the knee, causing pain, swelling, and limited range of motion.