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266 Biberstein et al. | Journal of Clinical and Translational Research 2024; 10(4): 263-268
without motion. Therefore, undersurface geometry and surface the tibial surface had cement coating. However, with the double-
roughness appear to be important factors in improving fixation at butter technique, the amount of tray contamination approached
the implant-cement interface as well. An additional noteworthy 0% contamination for every implant, with a significant
finding from their study was the inverse correlation between reduction noted for each implant. Interestingly, there were
lipid contamination of the tibial tray and implant fixation. significant differences among the various implants’ surface area
Specifically, increasing the surface area of the tibial tray that contamination suggesting that tibial undersurface geometries
was contaminated with lipids correlated with decreased implant can also affect lipid contamination [22].
pull-out strength. Therefore, we hypothesize that limiting the Our prior double-butter study led us to explore whether
amount of contamination of the undersurface of the tibial tray cement pockets significantly reduce lipid contamination of the
should theoretically improve implant fixation. implant-cement interface in this study. Interestingly, the surface
Additional factors known to negatively impact implant area of lipid contamination did significantly decrease with the
fixation include component malalignment, improper bone introduction of cement pockets to the tibial baseplate. The current
surface preparation and drying, poor cement technique including tibial implant design shares similar undersurface geometries,
mixing and handling, potentially high viscosity cements, and including a peripheral rim and a keel or stem. The peripheral
smaller cement mantles, as well as other intraoperative surgical rim is a design feature that allows for cement pressurization into
technique errors [10-14]. In addition, PMMA, a biologically bone. As the peripheral rim is inserted into the cement, fluid
inactive substance that forms through a chemical reaction, has is trapped under the tibial tray and is then dispersed along the
numerous potential aberrations that can compromise its strength implant-cement interface. The undersurface addition of cement
and stability when used in the clinical setting for TKA [10-12]. pockets did mitigate this dispersion, and in our study, we found
Billi et al. recently explored a variety of cement techniques, that the cement pockets were often filled with fluid (Figure 7).
evaluating the timing of bone cement application, as well as While this study appears to be the first to demonstrate that
lipid contamination. They noted that early cement application lipid/fluid contamination is influenced by the addition of cement
significantly improved implant fixation and that lipid
contamination led to a significant reduction in implant fixation.
They demonstrated that cement application to both bone and
the implant with a “double-butter” technique significantly
improved implant fixation when lipids were introduced into the
fixation interface [21].
We have recently demonstrated a potential mechanism for this
finding. In a previous study, we evaluated seven contemporary
tibial implant designs and observed that lipid contamination
commonly occurred at the implant-cement interface when only

Table 1. Tibial baseplate fluid contamination following simulated
implantation
Evaluation Fluid contamination (%)
Implant A Implant B Figure 6. Average tibial baseplate fluid contamination following
Trial 1 55.315 31.83 simulated implantation between implants A and B (p=0.0265)
Trial 2 37.025 23.575
Trial 3 36.125 35.685
Average* 42.82 30.36
Implant A has no pockets; implant B has pockets; *p-value of the average is 0.0265.

Figure 5. Example of implant A (left) and implant B (right) after Figure 7. A baseplate trial demonstrating the filling of a cementation
undergoing trial implantation pocket with fluid
DOI: https://doi.org/10.36922/jctr.24.00029