ONAS-DPS. Two plates are needed distally (Figure 1) since the femoral metaphysis is curved: the lower plate (subplate) is a specially designed “wedge plate” which makes the unilateral external fixator parallel to the bone. If ONAS-DPS is used with anterograde IM nail the wedge plate must be used proximally (not shown). Wedge plates with four different angles (thicknesses) are available with ONAS-DPS, each having an equivalent probe. The upper plate provides fixation to the bone with four angle stability screws. Each screw hole in the plate offers the possibility of placing the screw at any chosen angle from 90° to 65° with respect to the sagittal axis of the bone. Please note that the IM nail is in the medullary canal and that the plates are fixed with screws going anteriorly and posteriorly with respect to the IM nail. Proximally, a separate screw passes through both plates and cortical bone and goes through the IM nail and finally anchors into the opposite cortical bone. The two-plate system of the ONAS-DPS enables stable fixation of Schanz screws and also stable fixation of both plates to the bone, in this way avoiding direct contact between Schanz screws and IM nail, which is responsible for the high incidence of infection in standard LON.