The invention belongs to the technical field of surgical auxiliary positioning, and discloses an auxiliary positioning device for a
tibia longitudinal
osteotomy position in unicompartmental knee
arthroplasty, which comprises an operating
bed, an auxiliary positioning part is arranged on the operating
bed, and the auxiliary positioning part comprises an inclined plate support fixedly connected to the operating
bed. A fixed clamping plate is hinged to the top end of the inclined plate support, and a rubber clamping plate is fixedly connected into the inner wall of the fixed clamping plate; under the driving of an electric cylinder, an arc-shaped top plate indirectly rotates and generates up-and-down offset motion, so that when an arc-shaped rubber abutting plate is driven to passively move upwards, the shanks of a patient are lifted to rotate inwards and the flexion and extension gap between the
femur and the
tibia is measured, two shank fixing frame plates can expand in advance, and the motion of the two shank fixing frame plates is prevented from generating interference; therefore, the problem that an assistant manually drives an unconscious patient to do leg flexion and extension movement is solved, and meanwhile, the auxiliary positioning effect of operation on thighs and shanks of the patient can be achieved.