FIELD: medicine.SUBSTANCE: invention refers to medicine. A knee arthroplasty assembly comprises a basic instrument and adjustment instrument. The basic instrument is configured attachable in relation to a proximal portion of shin bone of the knee and comprises a reference element having a connection device of the reference element, which comprises an upper substantially flat surface and configured so that attaching the basic instrument in relation to the proximal portion of shin bone makes the upper substantially flat surface of the above connection device be positioned at a neutral inclination in the anterior/posterior direction in relation to the proximal portion of the shin bone and at a neutral valgus/varus angle in relation to the proximal portion of the shin bone. The adjustment instrument is configured attachable to the basic instrument and comprises a receiving mechanism and a connective device for an excision guide. The receiving mechanism is configured to receive at least a portion of the connective device of the reference element of the basic instrument to enable an angular adjustment of the adjustment instrument in relation to the basic instrument with regard to an axis substantially perpendicular to the upper substantially flat surface of the connective device of the reference element, when the connective device of the reference element is mounted into a seat, and adjust an advance of the adjustment instrument in relation to the basic instrument in the medial/lateral direction along the upper substantially flat surface of the connective device of the reference element when the connective device of the reference element is mounted in the receiving mechanism. The receiving mechanism limits an alignment axis. The connective device for the excision guide is directed at a preset inclination in relation to the alignment axis of the receiving mechanism and configured attachable to the excision guide.EFFECT: invention simplifies a procedure of knee arthroplasty
