A 12-year-old female presents to an outpatient sports medicine clinic with her guardian complaining of persistent right knee pain for the past two months. She is an active gymnast and has recently increased her training intensity, including more tumbling and jumping routines. She reports the pain worsens during and after activity, particularly when landing from jumps or kneeling. The guardian notes no prior significant medical history. On examination, vital signs are stable. There is mild swelling and tenderness to palpation over the tibial tubercle of the right knee. No erythema or warmth is noted, and joint effusion is absent. Range of motion of the knee is full, but resisted knee extension elicits pain at the tibial tubercle insertion. Strength is otherwise preserved. A recent plain radiograph of the right knee revealed fragmentation and irregular ossification at the tibial tubercle. What is the most appropriate initial management strategy for this condition, and what are the potential long-term complications that should be discussed with the patient and her family?

A 14-year-old boy presents to the general outpatient clinic with his guardian, reporting persistent right knee pain that has been bothering him for the past three months. He describes the pain as a dull ache after physical activity, escalating to a sharp pain during jumping, kneeling, or running. The discomfort is significantly impacting his performance in soccer and track. He denies any acute trauma or injury. His medical history is unremarkable, and he takes no regular medications, only occasionally using over-the-counter pain relievers. On physical examination of the right knee, there is a distinct bony prominence and localized tenderness directly over the tibial tuberosity. Mild swelling is noted in the area. The remainder of the knee examination, including patellar tracking and ligamentous stability, is within normal limits. Resisted knee extension elicits pain. Considering the clinical presentation, what is the most likely diagnosis and the appropriate initial non-pharmacological management plan?