RESUMO
BACKGROUND: Limb salvage surgery is an important method for treating malignant tumors of the bone involving the adjacent parts of the major joints in children. This technique allows for preservation of limb function, especially in the lower limb. However, the reconstruction of the proximal end of the tibia after removing the tumor mass with a rational scale to preserve the total knee joint and reduce limb length discrepancy presents a challenge. CASE PRESENTATION: We present a case of osteosarcoma of the proximal tibia. After being treated with an extended tumor resection, the proximal tibia of the child was restructured using endoprosthetic replacement with epiphyseal preservation. This procedure preserves the entire articular surface and growth plate of the knee joint of the affected limb and provides a feasible alternative protocol for retaining the function and growth potential of the affected limb. The patient remained disease-free and normal limb motor function was observed during the 3.5 year follow-up since the initial surgery. CONCLUSIONS: Preservation of the epiphysis enabled our patient to perform better limb function after limb-saving surgery as a result of his undamaged knee joint and minimized limb-length discrepancy. We believe that endoprosthetic replacement with preservation of the epiphysis can provide the best strategy for reconstruction after resection of focal malignant tumors in long bones without epiphytic involvement.