SYSTEM FOR USE IN KNEE SURGERY Russian patent published in 2019 - IPC A61B17/15 A61F2/38 

FIELD: medicine.

SUBSTANCE: group of inventions relates to medicine. System for use in knee surgery of a patient according to the second embodiment comprises a femoral component of a knee joint prosthesis. Femoral component of a knee joint prosthesis has a bearing surface for articulation with a tibial bearing surface and an opposite bone facing surface. In the femoral component, the bone facing surface comprises: an anterior portion for engaging the femur on its anterior side, a posterior portion for engaging the femur on its posterior side, a distal portion for engaging the distal end face of the femur, an anterior chamfer portion located between the anterior portion and the distal portion, which is inclined to each of the anterior portion and the distal portion, and a posterior chamfer portion located between the posterior portion and the distal portion, which is inclined to each of the posterior portion and the distal portion. Each of the anterior, distal, and posterior portions of the bone facing surface is characterised by the absence of rails on each edge and, accordingly, is planar, which means that it can form close inter-surface contact with the planar surface of the adjacent bone. Guide block has a planar distal surface which can be fastened to the distal face of a patient's femur on which the distal resection cut has been made to determine the locations relative to the plane of the distal resection cut of planes on which the anterior and posterior chamfer cuts can be performed, in which the distance between an anterior reference line extending parallel to the plane of the anterior chamfer cut and intersecting the plane of the distal surface at a point midway between the intersections between the planes of the distal surface and the anterior chamfer cuts and the planes of the distal surface and the posterior chamfer cuts, and the plane of the anterior chamfer cut is G_Ant, and the distance between a posterior reference line extending parallel to the plane of the posterior chamfer cut and intersecting the plane of the distal surface at a point midway between the intersections between the planes of the distal surface and the anterior chamfer cuts and the planes of the distal surface and posterior chamfer cuts and the plane of the posterior chamfer cut is G_Post. Anterior chamfer portion of the bone facing surface of the femoral component has spaced-apart medial and lateral rails with at least one recess between them. Distance between an anterior implant reference line extending parallel to the anterior chamfer portion of the bone facing surface and intersecting the distal portion of the said surface at a point midway between the intersections between the distal portion and the anterior and posterior chamfer portions and, the tip edge of the rails being I_AntRail, and the distance between the anterior implant reference line and the base of the recess between the rails being I_AntRecess, the value of (I_AntRecess - G_Ant) being at least 0.5 mm, so when positioning the femoral component on the femur of the patient, there is contact between the anterior, distal, posterior, anterior chamfer and posterior chamfer portions of the surface of the femoral component facing the bone and the corresponding surfaces of the femur. Upper edges of the medial and lateral rails are in contact with the anterior chamfer surface of the femur of the patient and there is a gap between the anterior chamfer surface of the patient's femur and the base of the recess. And / or the posterior chamfer portion of the surface of the femoral component facing the bone has spaced-apart medial and lateral rails with at least one recess between them. Distance between the posterior basis line of the femoral component extending parallel to the posterior chamfer portion of the surface facing the bone and intersecting the distal portion of the said surface at the half-way point between the intersections between the planes of the distal surface and the anterior and posterior chamfer portions, and the upper edges of the rails I_PostRail and the distance between the posterior baseline of the femoral component and the base of the recesses between the rails I_Postrecess, value (I_Postrecess - G_Post), is at least 0.5 mm, so that when positioning the femoral component on the femur of the patient, there is contact between the anterior, distal, posterior, anterior chamfer and posterior chamfer portions of the surface of the femoral component facing the bone and the corresponding surfaces of the femur. Upper edges of the medial and lateral rails are in contact with the posterior chamfer surface of the patient's femur and there is a gap between the posterior chamfer surface of the patient's femur and the base of the recess. System for use in knee surgery of a patient according to the second embodiment comprises a femoral component of the knee prosthesis and a guide block. Femoral component of a knee joint prosthesis has a bearing surface for articulation with a tibial bearing surface and an opposite bone facing surface. Surface facing the bone comprises an anterior portion for engaging with the femur on its front side, a posterior portion for engaging with the femur on its back side, distal portion for engagement with the distal end surface of the femur, anterior chamfer portion located between the anterior portion and the distal portion, which is arranged at an angle to the anterior portion, and to the distal portion, and the rear chamfer portion, located between the rear portion and the distal portion, which is located at an angle to both the rear portion and the distal portion. Each of the following: the anterior, anterior chamfer, the posterior chamfer, and the posterior of the bone-facing surface are characterised by the absence of rails on each edge and, accordingly, is flat, and therefore, can form close inter-surface contact with the flat surface of the adjacent bone. Distal portion of the bone-facing surface has spaced-apart medial and lateral rails with at least one recess between them. Guide block has a flat distal surface that can be attached to the distal surface of the patient's femur, on which a distal resection slice was made to determine its position relative to the plane of the distal resection slice of the planes in which the anterior and posterior cuts can be made. Guide block determines the baseline of the guide block at the intersection of the planes of the anterior and posterior sections so that the distance between the baseline and the flat distal surface is G_Dist. Distal portion of the surface of the femoral component facing the bone has spaced-apart medial and lateral ribs with at least one recess between them. Distance between the baseline of the femoral component lies at the intersection of the anterior and posterior planes of the surface facing the bone and the upper edges of the rails I_DistRail and the distance between the baseline of the femoral component and the base of the recesses between the rails I_Postrecess, value (I_Postrecess - G_Post) is at least 0.5 mm, so when positioning the femoral component on the femur of the patient, there is contact between the anterior, distal, posterior, anterior chamfer and posterior chamfer portions of the surface of the femoral component facing the bone and the corresponding surfaces of the femur. Upper edges of the medial and lateral rails are in contact with the distal surface of the femur of the patient and the lumen between the posterior chamfer surface of the femur of the patient and the base of the recess.

EFFECT: inventions provide effective restriction of the movement of the femoral component to the end of the femur.

22 cl, 20 dwg