Differential Diagnosis for Athletic Teen with Knee Pain

Single Most Likely Diagnosis

• Osgood-Schlatter Disease: This condition is characterized by pain, swelling, and tenderness below the knee, specifically at the proximal tibia, which matches the patient's symptoms. It is common in adolescents, especially during growth spurts, and is exacerbated by activities that involve running, jumping, and quick changes of direction, aligning with the patient's history of pain worsening with running and stair climbing.

Other Likely Diagnoses

• Patellofemoral Pain Syndrome: This condition causes pain around or behind the patella (kneecap), often associated with activities that put stress on the knee, like running, jumping, and climbing stairs. While the primary location of pain is different, some patients may experience referred pain or tenderness in the proximal tibia area.
• Medial Tibial Stress Syndrome (Shin Splints): Although more commonly associated with pain in the lower two-thirds of the tibia, some cases can present with pain higher up, potentially overlapping with the proximal tibia. It's a common overuse injury in runners and jumpers.
• Sinding-Larsen-Johansson Syndrome: This condition affects the distal pole of the patella and is similar to Osgood-Schlatter disease but involves the knee cap instead. It could be considered if the pain is more proximal and related to the patellar tendon.

Do Not Miss Diagnoses

• Tumor (e.g., Osteosarcoma): Although rare, bone tumors can present with pain and swelling. It's crucial to consider this diagnosis to ensure timely treatment if present.
• Infection (Osteomyelitis or Septic Arthritis): Infections in the bone or joint can cause severe pain, swelling, and systemic symptoms like fever. Early diagnosis is critical for effective treatment.
• Fracture (Stress or Traumatic): A fracture could cause localized pain and swelling, especially if there's a history of trauma or overuse.

Rare Diagnoses

• Binding-Larsen Syndrome: A rare condition that affects the iliotibial band and can cause knee pain, but it's less common and typically presents with different symptoms.
• Hoffa's Syndrome: Involves the infrapatellar fat pad and can cause anterior knee pain, which might be considered if the pain is more localized around the knee cap.

Each of these diagnoses should be considered in the context of the patient's full history, physical examination, and potentially, diagnostic imaging to determine the most appropriate diagnosis and treatment plan.