METHOD OF MANUFACTURING A LOWER LEG EXOPROSTHESIS SLEEVE Russian patent published in 2023 - IPC A61F2/76 A61F2/80 

FIELD: medicine; technical orthopedics.

SUBSTANCE: invention is intended for the manufacture of a socket for exoprosthetics. The method of manufacturing a sleeve for a prosthesis of the lower leg consists in putting a silicone liner on the stump of the lower leg, the patient is placed sitting on a chair so that the lower part of the thigh is not pressed to the surface, and the stump of the lower leg is in the air. Palpation of the stump is carried out. A protruding plasticine border is applied to the patient's stump in a silicone liner in the projection of bone landmarks that require further modifications on a digital model. A protruding border of plasticine is applied in the region of the patella and condyles of the femur in the area of the intended upper contour of the sleeve. The patient is asked to bend and straighten the leg at the knee joint and make sure that the markings are correct. A 3D data array is recorded from the surface of the stump using non-contact measurement methods in three positions of the stump: full extension in the knee joint, flexion at an angle of 90°, in a relaxed position. The contralateral limb is scanned in a vertical position. The images obtained as a result of scanning are sent to a mobile device paired with a 3D scanner through a mobile application recommended by the equipment manufacturer. The data is then transferred to a personal computer for further processing. In a software package that supports polygonal modeling, the sequence of stages of digital material transformation is followed: the surfaces obtained from different positions of the limb are combined. The removal of artifacts and unnecessary elements are performed. The model is oriented in accordance with the individual characteristics of a particular patient. The surface of the stump is smoothened. The length of the perimeter of the stump model is reduced from the region of the patellar ligament in the range of 0–5% depending on the impedance of the patient's soft tissues. Gradient elevation of the surface is performed in the projection of bone landmarks marked with a border. The upper contour of the sleeve is formed taking into account the visualized marks. An inner layer of the sleeve, coplanar to the surface of the stump is created. The outer layer of the sleeve is formed by reflecting a three-dimensional image of the contralateral limb. The sleeve model is given a thickness of 3.84 mm over the stump. Taking into account the scheme of constructing the prosthesis, a landing site is located for placing the sleeve adapter and the two objects are merged. Stiffening ribs are additionally created in the connection area. The end part of the stiffeners is modeled in accordance with the shape of the contralateral limb. The physical model of the lower leg prosthesis sleeve is obtained using a 3D printer using FDM technology. Before printing the sleeve slicing the model in software recommended by the manufacturer of additive equipment is carried out. An incomplete filling of the material up to 50% is designed between the inner and outer walls of the sleeve in the areas of the stump that are most sensitive to the load. PETG plastic is used as the printing material. When printing, an extruder nozzle with a diameter of 0.8 mm is used. The following print settings are determined: the nozzle temperature is set to 241°C, table heating is 75°C, layer height is 0.25 mm, average printing speed is 45 mm/s, the billet is not blown. Supports are made of the material of the main part.

EFFECT: invention ensures the production of a highly personalized prosthetic module — a sleeve of a transtibial prosthesis.

1 cl, 2 ex, 5 dwg