Surface pretreatment for prolonged survival of cemented tibial prosthesis components: full- vs. surface-cementation technique.
BACKGROUND
One of few persisting problems of cemented total knee arthroplasty (TKA) is aseptic loosening of tibial component due to degradation of the interface between bone cement and metallic tibial shaft component, particularly for surface cemented tibial components. Surface cementation technique has important clinical meaning in case of revision and for avoidance of stress shielding. Degradation of the interface between bone cement and bone may be a secondary effect due to excessive crack formation in bone cement starting at the opposite metallic surface.


METHODS
This study was done to prove crack formation in the bone cement near the metallic surface when this is not coated. We propose a newly developed coating process by PVD layering with SiOx to avoid that crack formation in the bone cement. A biomechanical model for vibration fatigue test was done to simulate the physiological and biomechanical conditions of the human knee joint and to prove excessive crack formation.


RESULTS
It was found that coated tibial components showed a highly significant reduction of cement cracking near the interface metal/bone cement (p < 0.01) and a significant reduction of gap formation in the interface metal-to-bone cement (p < 0.05).


CONCLUSIONS
Coating dramatically reduces hydrolytic- and stress-related crack formation at the prosthesis interface metal/bone cement. This leads to a more homogenous load transfer into the cement mantle which should reduce the frequency of loosening in the interfaces metal/bone cement/bone. With surface coating of the tibial component it should become possible that surface cemented TKAs reveal similar loosening rates as TKAs both surface and stem cemented. This would be an important clinical advantage since it is believed that surface cementing reduces metaphyseal bone loss in case of revision and stress shielding for better bone health.
Marx
Rudolf
R
Department of Prosthetic Dentistry, University Hospital of the University of Technology, Aachen, Germany. marx@rwth-aachen.de
Qunaibi
Mutaz
M
Wirtz
Dieter Christian
DC
Niethard
Fritz Uwe
FU
Mumme
Thorsten
T
D000268:Adhesiveness; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods*; D001843:Bone Cements / Q000032:analysis / Q000737:chemistry*; D002484:Cementation / Q000379:methods*; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry*; D019544:Equipment Failure Analysis; D006801:Humans; D007720:Knee Prosthesis; D008422:Materials Testing; D010865:Pilot Projects; D013977:Tibia / Q000503:physiopathology* / Q000601:surgery
D001843:Bone Cements; D020099:Coated Materials, Biocompatible