METHOD FOR REPLACEMENT OF DEFECTS OF DISTAL FEMUR IN PERFORMING KNEE JOINT REPLACEMENT AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2020 - IPC A61B17/56 A61F2/38 

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to traumatology and orthopedics, and can be used in operations of primary and revision knee arthroplasty in presence of massive defect of distal femur. At the stage of preoperative planning, performing, by means of multisliral computed tomography data, constructing a three-dimensional model of a distal femur with a defect and replacing an augmentation defect by additive techniques with using CT images of the contralateral femoral bone if necessary, as well as taking into account the femoral component of the endoprosthesis and the planned augment with their mutual positioning. Individual shape of the augmentation body is determined taking into account the bone defect configuration. Planned and marked on 3D models of augment are smooth and porous zones of its surface, thickness of its walls is planned, necessary axes are planned by means of virtual reconstruction relative to bone reference points. Further, a final version of an augment completely compensating for the existing bone defect and a congruent adjoining surface of the femoral component of the endoprosthesis is created. At the next step, 3D printing of a plastic prototype of the augment and a plastic model of the distal femur with a bone defect is performed, and after fitting and fitting by smoothing the edges of the bone defect to facilitate the augmentation taking into account the femoral component of the endoprosthesis. After its fitting with the femoral component of the endoprosthesis, 3D printing of augmented anode from powdered titanium in full compliance with created 3D model. At the stage of the reconstructive surgery, the individually planned augmentation to the defect of the distal femur is first set, smoothing the edges of the bone defect, if necessary, and excising the existing scar tissue. After achieving the required congruence, a standard femoral component of the endoprosthesis is installed using the bone cement under the required angle of inclination and taking into account the planned axes and anatomical marks by the method of tight fit. Device for defect replacement of the distal femur for implementation of the method includes a hollow body in a personified form made using additive technologies based on three-dimensional modeling at the stage of surgical intervention planning. Body is made on individual relief of distal femur in compliance with existing defect. Inner surface of the body is congruent with the mating surface of the endoprosthesis component. Outer surface of housing is made with individually selected smooth and porous zones depending on diligence of surrounding soft-tissue structures. Thickness of body walls is selected taking into account features of individual anatomy of patient and value of bone defect at preoperative planning stage.

EFFECT: method provides support ability and recovery of lower extremity function, as well as a full support for the femoral component of the knee joint endoprosthesis and its strong primary fixation; accurate filling of bone tissue defect with reconstruction of anatomical shape of injured femur due to low traumatism and preservation of maximum possible volume of involved thigh bone.

2 cl, 9 dwg, 2 ex