A 13-year-old boy presented to the orthopedic clinic with a 1-week history of bilateral knee pain

A 13-year-old boy presented to the orthopedic clinic with a 1-week history of bilateral knee pain. He was active in sports and participated in long jump. Examination of the right knee showed mild soft-tissue swelling and tenderness over the tibial tubercle, and a taut quadriceps muscle; the exam of the left knee was normal. Plain radiographs of both knees were done. What is the likely diagnosis?

Hoffa’s syndrome
Patellar tendon avulsion
Pes anserine bursitis
Osteomyelitis of the proximal tibia
Osgood–Schlatter disease