ObjectiveTo investigate the feasibility and effectiveness of proximal tibial hemiprosthesis replacement in the first stage and prosthesis revision in the second stage in reducing the risk of length discrepancy of limbs in children with proximal tibial osteosarcoma.MethodsBetween 2009 and 2013, 3 children with conventional osteosarcoma at the proximal tibia (stage ⅡB) were treated. There were 2 boys and 1 girl. They were 12, 13, and 13 years old, respectively. After 4 courses of preoperative chemotherapy, the proximal tumor segmental resection and proximal tibial hemiprosthesis replacement were performed. Then the patients underwent prosthetic revision in the second stage when they were 20, 17, and 17 years old, respectively.ResultsAll patients successfully completed two stages of operations. The length discrepancy of lower limb after the second stage operation were 19, 7, and 21 mm, respectively. Three patients were followed up 13, 3, and 27 months after the second stage operation, and the lower extremities functions were satisfactory. The Musculoskeletal Tumor Society (MSTS) score was 26, 27, and 25, respectively.ConclusionThe proximal tibial hemiprosthesis replacement in the first stage combined with prosthesis revision in the second stage for treating the proximal tibia osteosarcoma in children can keep the distal femur growth ability, reduce the length discreapancy of lower limb, and obtain satisfactory stability and good function.