The main advantages of the М2а-Magnum modular system pair are the presence of a group of metals metal with wear of the large head, which is the maximum value that makes it possible to increase the range of motion in the hip joint by more than 160 with virtually no risk of dislocation [1]. This allows you to freely conduct active work and sports. However, the system is not without drawbacks. First of all, this is the unrevealed danger of damage to metal ions in the blood, as well as the problem of the development of a pseudotumor lymphoid reaction [2,3], leading to extensive osteolysis, an increased risk of periprosthetic fractures, and, accordingly, an increase in the frequency of endoprosthesis destabilization. Currently, the use of constructions is practically suspended, but there are more than 1 million patients in the world [4] with implanted large "metals - metal pairs". In revision surgery with M2a-Magnum implants, the main problem is often the inability to remove the femoral head adapter component from the neck taper. fretting corrosion is observed, leading to the effect of cold welding. The latter is typical for the connection of titanium surfaces (adapter of the head module and the neck of the femoral component). It turns out that it should be noted that the M2a-38 system does not have a titanium adapter made of a cobalt-chromium alloy and devoid of this problem [4].