[Significance of jet lavage for in vitro and in vivo cement penetration].
OBJECTIVE
The purpose of this study was to determine the efficacy of pulsatile jet lavage and manual syringe lavage with regard to their cleansing capabilities as measured by cement penetration into cancellous bone both in vivo and in vitro.


METHODS
Three separate experiments were performed. Study A: In a cadaver study 36 left human cadaver femora were used for implantation of cemented femoral components. Conventional broaches were used for femoral preparation. Bone lavage was carried out either using jet lavage or manual syringe lavage of equal volume. The allocation to two different lavage groups was randomised. In both groups high-pressurising cementing techniques were implemented with the use of a proximal seal and additional finger packing. Study B: To guarantee standardised cement pressurisation and equal bone quality, the influence of jet lavage (1000 ml) versus syringe lavage (1000 ml) was studied in 11 paired human cadaver femora in an additional study without prosthesis implantation. The specimens were imbedded in specially designed pots. Bone cement was applied in a retrograde manner and subjected to a standard pressure protocol with a constant force of 3000 N. Study C: To directly compare the effectiveness of both pulsatile jet and syringe lavage with regard to cement penetration in vivo, a new sheep model allowing for standardised bilateral, simultaneous cement pressurisation was used. After femoral neck osteotomies both femoral cavities of 10 sheep were prepared for retrograde cement application. After randomisation one side was lavaged with 250 ml irrigation using a bladder syringe, the contralateral femur with the identical volume but using a pulsatile lavage. A specially designed apparatus was used to allow for bilateral simultaneous cement pressurisation.


METHODS
In all studies horizontal sections were obtained from the femoral specimens at predefined levels using a diamond saw. Microradiographs were taken and analysed using image analysis to assess cement penetration into cancellous bone.


RESULTS
Study A: Compared with syringe lavage the use of jet lavage significantly improved the penetration of cement into cancellous bone (p = 0.027). In the presence of strong, dense cancellous bone the findings were more pronounced. Study B: Our results show that in equal quality bone, the use of jet lavage yields significantly (p < 0.001) improved cement penetration compared to syringe lavage specimens. Study C: The results of the in vivo study confirmed the superiority of jet lavage bone surface preparation (p = 0.002).


CONCLUSIONS
The use of jet lavage yields significantly improved interdigitation between cancellous bone and cement both in vitro and in vivo and should be regarded as mandatory in cemented total hip arthroplasty. High pressurising techniques are effective means to improve cement penetration, but should only be administered with jet lavage to reduce the risk of fat embolism.
Abteilung Orthopädie I, Stiftung Orthopädische Universitätsklinik Heidelberg. steffen.Breusch@urz.uni-heidelberg.de
S J
SJ
Breusch
U
U
Schneider
T
T
Reitzel
J
J
Kreutzer
V
V
Ewerbeck
M
M
Lukoschek
D000818:Animals; D019644:Arthroplasty, Replacement, Hip; D001843:Bone Cements; D019544:Equipment Failure Analysis; D005269:Femur / Q000473:pathology; D006801:Humans; D006874:Hydrostatic Pressure; D019904:Polymethyl Methacrylate / Q000008:administration & dosage*; D012756:Sheep; D007507:Therapeutic Irrigation
D001843:Bone Cements; D019904:Polymethyl Methacrylate