An 8Year old child came with a deformity in his right leg since 2 years which has been progressive. They give history of tibial fracture 3 years back treated with cast immobilization. Clinically there is deformity of proximal tibia and restriction of knee ROM.

X-ray, MRI done is as shown. Biopsy done at another center from the lesion showed hyaline cartilage-like material. What is your diagnosis and how would you manage it?