The extracortical clamp device (ECD) is a tool used in external fixation which unlike the K-wires and half-pins don’t perforate cortical bone. The use of ECD is prospective for the treatment of periprosthetic femoral fractures and in the lengthening over nail and bone transport over nail. The data on the bench tests of the osteosynthesis rigidity by the external fixation first-order and second-order modules on the base of extracortical clamp devices are observed in the article. Materials and methods. The authors made 240 bench tests using torsional-vibration machine, Indicators measuring linear displacements with a scale of 0.01 mm, bone simulators («Sawbones»), calibrated load, Ilizarov’s apparatus и extracortical fixators. The statistical analysis was performed with use software «STATISTICA» (ver. 6.0). The data obtained are presented in graphs «Box and Whisker Plot». Results. Among the investigated variants of first-order modules the better results of osteosynthesis rigidity were found in the module based on two ECD inserted at angle 60 degrees to each other and at distance of 10 cm from each other. Among the investigated second-order modules, better results of osteosynthesis rigidity were found in the module based on two ECD inserted at an angle 60 degrees to each other at distance of 10 cm from each other. Conclusion. Thus the tested modules can be used in practice in assemblies of external fixation devices in periprosthetic fractures, lengthening and bone transport over the nail.