Inclusion Criteria:  Megaprosthesis of the distal femur Tumor cause  Exclusion Criteria:  Neurological alterations prior to the intervention that affect the lower limbs or general movement. Patient incapable of ambulation due to progression of his/her pathology Patient at home with palliative treatment for advanced tumor disease Proximal or complete femur megaprosthesis Infectious, traumatic cause or sequel to revision surgery