["Erlangen Model" titanium socket. Study of the biomechanics of the "Erlangen Mode" titanium socket with and without...

A multitude of prostheses are available for the reconstruction of severely arthrotic hip joints--especially for revising total arthroplasty. In order to find out more about the biomechanical efficiency of these special implants, we carried out computerized analyses on how the distribution of stress within the pelvis changes when employing the titanium socket component "Erlanger Modell" [TiAl 5 Fe 2.5], which can be used with a supporting ring in order to transfer the stress on the hip joint to the iliac bone and to the pubic bone in case the acetabulum should not be able to provide the stability needed by the socket. In a procedure described by Herzog, strain gauges are attached to the pelvis of freshly slaughtered cattle at the following sites, transmitting the relative bone expansion and torsion to a multipoint measuring instrument (Linseis L2100) and on-line to a computer: (1) superior ramus of the pubic bone; (2) front edge of the socket at the iliopubic eminence; (3) iliac bone on the outside of the pelvis; (4) socket roof, pars ossis ilei in the small pelvis; (5) socket roof, pars ossis ischii in the small pelvis. The quality of the implantation was monitored by the non-delayed force transmission from the femur through the hip arthroplasty onto the pelvis. With stress varying from 0 to 500 N in steps of 125 N we carried out four complete readings in order to ensure the reproducibility of the measurements.(ABSTRACT TRUNCATED AT 250 WORDS)