Cementless Hydroxyapatite Coated Hip Prostheses

Abstract

More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality.

Radiographic evaluation of early periprosthetic acetabular bone contrast and prosthetic head acetabular coverage after uncemented and cemented total hip prosthesis in dogs

“…The principal role of THA is to restore an adequate range of motion to the coxofemoral joint while transferring load from the acetabulum allowing early weight bearing [6]. The main goal of THA is to improve the survival of the implant and enhance the limb function in the short and long terms [7]. However, alteration in bone remodeling around the prosthetic implants may result in changes in the adjacent bone density [8].…”

Biomechanical properties of hip implant with ceramics coating

“…Contacts between the hip implant and femur, as well as compact and sponge bones were assigned via contact elements Conta173, Conta174 and Targe170 (without sliding and penetration) what can be interpreted as fully recovering after surgery. The boundary conditions for the femur correspond to rigid fixing of half [2,3,6]. The finite element model of the femur bone after hip replacement surgery and locations of muscle attachment area are shown in figure 1.…”

“…The cortical bone and the trabecular bone were taken as orthotropic homogenous. The properties of hydroxyapatite are taken from the research [2,8]. Stress-strain states of the femur bone after the total hip replacement were derived for two cases.…”

“…A lot of finite element studies were carried out to assess the influence of the hip implant. Recently obtained results and the history of the development of this problem are described in [2][3][4]. Usually, in the works related to the calculation of the stress-strain state of hip implant system effect of stress shielding is not considered.…”

“…Usually, in the works related to the calculation of the stress-strain state of hip implant system effect of stress shielding is not considered. The hip transplant with hydroxyapatite coated stem was investigated in clinical studies [2,11]. The specification of a material model for a bone and transplantation in finite element studies is still relevant.…”