Abstract: Provided are a surgical instrument and a surgical instrument system which has a simple structure and with which an osteotomy can be done with a simple operation. A surgical instrument includes a spacer part having a predetermined thickness, a guide part extending in a direction perpendicular to the guide part. The spacer part includes a first surface that abuts on one of posterior condyles of a femur at a bent position of a knee joint. The guide part includes a second surface that extends perpendicular to the first surface and abuts on a distal end part of the femur, and a guide slit penetrating the guide part along a direction parallel to the first surface and through which an osteotomy instrument is inserted.

Abstract: Provided is a measuring instrument for use in artificial knee joint replacement surgery that can perform knee joint alignment measurement more accurately. A measuring instrument for use in artificial knee joint replacement surgery includes a guide section. The guide section is used to indicate, from the outside of a patient, the position of a femoral head center of a hip joint of the patient. The guide section indicates the position of the femoral head center while being arranged based on preliminarily measured relative positions of an anterior superior iliac spine and the femoral head center of the patient. The anterior superior iliac spine is viewable from the outside of the patient.

Abstract: A surgical measurement instrument for use in surgery is configured so that a measurement operation can be more readily performed using this surgical measurement instrument. The surgical measurement instrument has a laser application portion. The laser application portion is used in surgery to perform treatment on a tibia of a patient. The laser application portion can apply a laser beam to measure a positional relationship between the tibia and a knee joint center.

Abstract: Provided is a measuring instrument for use in artificial knee joint replacement surgery that can perform knee joint alignment measurement more accurately. A measuring instrument for use in artificial knee joint replacement surgery includes a guide section. The guide section is used to indicate, from the outside of a patient, the position of a femoral head center of a hip joint of the patient. The guide section indicates the position of the femoral head center while being arranged based on preliminarily measured relative positions of an anterior superior iliac spine and the femoral head center of the patient. The anterior superior iliac spine is viewable from the outside of the patient.