Van Nes rotationplasty has gained popularity as a surgical treatment for malignant bone tumors without resorting to amputation. However, the nature of the surgery poses unique challenges in the rehabilitation management in order to optimize safety and functional mobility. We describe a case of a 6-year-old female with Ewing’s sarcoma of the right femur who underwent Van Nes Type BIIIA rotationplasty. This procedure involved a complete femoral resection, with the tibia and the foot rotated by 180 degrees and the lateral tibial plateau placed into the acetabulum that is expected to remodel to form a neo-hip joint. The patient was referred to rehabilitation medicine and was eventually admitted due to impairment in mobility secondary to the surgery. The goal was to achieve K-1 level of function. This case demonstrates that the rehabilitation management of a child with Type B-IIIA rotationplasty using a modified Van Nes prosthesis requires a comprehensive multidisciplinary approach.