FIELD : medicine.SUBSTANCE : invention refers to medicine, namely to arthrology, and can be used for surgical treatment of deforming arthrosis of the first metatarsophalangeal joint. A medial approach to the first metatarsophalangeal joint is performed. It involves simulating resection of the head of the first metatarsal bone and resection of exostosis on the lateral surface of the head of the first metatarsal bone. Z-shaped osteotomy is performed with fixation of bone fragments with titanium screws. I finger is dislocated and a base phalanx base is resected within a subchlear layer. Then, a dura mater folded three times and cross-linked by a continuous surgical suture from a dura mater sized to the size of a bone bed is fixed transosseously to the base of the main phalanx through the holes prepared along the perimeter of a bone bed. Hemostasis is performed, wound is closed tightly.EFFECT : method provides joint decompression, increased motion amplitude, preservation of length of first toe, reduced length of treatment and disappearance of pain syndrome due to arthroplasty of first metatarsophalangeal joint in combination with Z-shaped osteotomy.1 cl, 12 dwg