A system of reconstruction for a spinal joint is directed to a modular implant assembly that includes an upper part and a lower part. The upper and lower parts each comprise a unitary body having an approximately ninety degree bend defining vertical and horizontal components. Each vertical component has a fastener hole for attaching it to a bone segment using a bone fastener. The horizontal sections each have a complementary contact surfaces in order to transmit compressive load therebetween and to accommodate sliding and pivoting relative movement therebetween. The vertical sections of each of the upper and lower part are offset with respect to a vertical centerline so that successive assemblies bridging more than one adjacent vertebral space can have an upper part and a lower part according to the present invention coexist on a single vertebra in a space-efficient manner wherein the vertical sections nest spatially.