[Application of an amphiphilic bonder in a goat model to increase the femoral cement-bone adhesion in cemented hip arthroplasty].
OBJECTIVE
Cemented revision of femoral components in total hip arthroplasty has shown high rates of early loosening due to reduced micro- and macroretention of the cement to the endostal bone stock. Enhanced stability can be reached by an amphiphilic bonder, which offers a covalent bonding of the hydrophobic cement to the hydrophilic bone. The aim of this study is to evaluate the biocompatibility of such a bonder and its effects on the mechanical stability of cemented hip arthroplasty stems in vivo.


METHODS
Total cemented hip arthroplasties were performed in 20 sheep. In the verum group (n = 10) the implant bed was preconditioned by application of the bonder prior to femoral stem implantation. To study the biocompatibility around the bone-cement interface fluorescent marking of osteoblasts was applied in vivo throughout the observation period of 9 months. Native X-rays of the hip joints were obtained immediately after implantation and after euthanasia. The bone-cement interface was examined histologically.


RESULTS
All stems of the verum group showed firm bonding of cement to bone in manual testing, while in 7 of the 10 controls the stems with adherent cement could be easily pulled out off the bony implant bed. This was coherent with significantly higher rates of progredient radiolucent lines and soft-tissue interpositions between bone and cement in the control group. The bonder was biocompatible.


CONCLUSIONS
When preconditioned with an amphiphilic bonder, cemented stems showed a markedly higher adhesive strength to the cancellous bone without signs of inflammation or neoplasia. This procedure might offer enhanced longevity of cemented femoral revision stems in hip arthroplasty.
Müller-Rath
R
R
Orthopädische Klinik, RWTH Aachen. rmueller-rath@ukaachen.de
Wirtz
D
D
Andereya
S
S
Gravius
S
S
Hermanns-Sachweh
B
B
Marx
R
R
Mumme
T
T
D000268:Adhesiveness; D000818:Animals; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D001843:Bone Cements / Q000737:chemistry* / Q000494:pharmacology*; D002484:Cementation / Q000379:methods*; D005269:Femur / Q000737:chemistry* / Q000166:cytology / Q000187:drug effects* / Q000601:surgery; D006041:Goats; D057927:Hydrophobic and Hydrophilic Interactions; D023421:Models, Animal
D001843:Bone Cements