Objective. To investigate the biomechanical performance of a newly designed cervico-trochanteric
stemless prosthesis by comparing the stress distribution with that of the traditional
stem-type porous-coated anatomic prosthesis.
Design. Three-dimensional finite element models were created for the intact femur, cervico-trochanteric
implanted femur and porous-coated anatomic implanted femur. The stress distributions
on the femur and the implant were compared. The effects of using two or three screws
fixation for the cervico-trochanteric implanted femur were also investigated.
Background. Local bone loss after implantation of traditional stem-type prostheses remains an
unsolved problem during the long-term application of total hip replacement. The stress
shielding effect and osteolysis were thought to be the two main factors that result
in local bone loss after prosthesis implantation. In order to eliminate the mechanical
and the biological causes of bone loss after total hip arthroplasty, a newly designed
stemless femoral prosthesis was investigated.
Methods. Three-dimensional finite element models were created for the intact, cervico-trochanteric
(with two or three fixation screws), and porous-coated anatomic implanted femora with
the geometry of a standardized composite femur. Analysis was performed for a loading
condition simulating the single-legged stance. The von Mises stress distributions
of each model were analyzed and compared.
Results. The results can be summarized as follows: (1) Von Mises stress in the proximal,
medial femur for the cervico-trochanteric implanted model was higher than that of
the intact model and the porous-coated anatomic implanted model; (2) stress-shielding
effect of the cervico-trochanteric models (with two or three fixation screws) were
eliminated as compared with the porous-coated anatomic model; (3) no obvious difference
in von Mises stress distribution for the cervico-trochanteric implanted model with
two or three fixation screws.
Conclusions. The cervico-trochanteric femoral prosthesis may reduce the stress-shielding effect
of the proximal femur and achieve a more physiological stress distribution on the
proximal femur than that of the porous-coated anatomic prosthesis.Relevance
The new concept of cervico-trochanteric stemless prosthesis has proven to possess
several advantages based on the current results, and may be an alternative for traditional
stem-type prostheses in future clinical applications.