The significance of pulsatile lavage for improved in vitro and in vivo cement penetration.

Aim: The purpose of this study was to determine the efficacy of pulsatile j et lavage and manual syringe lavage with regard to their cleansing capabili ties as measured by cement penetration into cancellous bone both in vivo an d 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 p reparation. Bone lavage was carried out either using jet ravage or manual s yringe lavage of equal volume. The allocation to two different lavage group s was randomised. In both groups high-pressurising cementing techniques wer e implemented with the use of a proximal seal and additonal finger packing. Study B: To guarantee standardised cement pressurisation and equal bone qu ality, the influence of jet lavage (1000 ml) versus syringe lavage (1000 mi ) was studied in 11 paired human cadaver femora in an additional study with out prosthesis implantation. The specimens were imbedded in specially desig ned 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 di rectly compare the effectiveness of both pulsatile jet and syringe lavage w ith regard to cement penetration in vivo, a new sheep model allowing for st andardised bilateral, simultaneous cement pressurisation was used. After fe moral neck osteotomies both femoral cavities of 10 sheep were prepared for retrograde cement application. After randomisation one side was lavaged wit h 250 ml irrigation using a bladder syringe, the contralateral femur with t he identical volume but using a pulsatile ravage. A specially designed appa ratus was used to allow for bilateral simultaneous cement pressurisation. A nalysis: In all studies horizontal sections were obtained from the femoral specimens at predefined levels using a diamond saw. Microradiographs were t aken and analysed using image analysis to assess cement penetration into ca ncellous bone. Results: Study A: Compared with syringe lavage the use of je t lavage significantly improved the penetration of cement into cancellous b one (p = 0.027). In the presence of strong, dense cancellous bone the findi ngs were more pronounced. Study B: Our results show that in equal quality b one, 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 prep aration (p = 0.002). Conclusions: The use of jet lavage yields significantl y improved interdigitation between cancellous bone and cement both in vitro and in vivo and should be regarded as mandatory in cemented total hip arth roplasty. High pressurising techniques are effective means to improve cemen t penetration, but should only be administered with jet lavage to reduce th e risk of fat embolism.