Depth Of Cement Penetration Research Articles

Total Knee Arthroplasty: The Impact of Tourniquet Usage on Cement Penetration, Operation Time, and Bleeding Control

Objective: The cementing technique employed in total knee arthroplasty (TKA) significantly influences the penetration of cement into the bone, ultimately affecting the stability of the joint. This study aimed to assess the impact of tourniquet usage on tibial cement penetration, operative time, bleeding, and functional outcomes following TKA. Materials and Methods: A retrospective evaluation was conducted on 103 patients who had undergone TKA and had a minimum follow-up period of 2 years. The patients were categorized into three groups: Group 1 utilized a tourniquet throughout the entire surgery, Group 2 released the tourniquet immediately after prosthesis implantation, just before cement hardening, and Group 3 did not employ a tourniquet at any stage of the procedure. Tibial cement penetration was assessed via X-ray examination, following the Knee Society Scoring System criteria. Operative time, bleeding levels, and Lysholm and Oxford scores were compared among the groups. Statistical analysis was performed using SPSS version 22.0 software. Results: In Group 1, bone penetration of cement was significantly higher than in both Group 2 and Group 3, except for zone 1 in the anterior-posterior (AP) view (p < 0.017). Group 3 exhibited significantly less bleeding compared to the other groups (p < 0.017). There was no significant difference in terms of bleeding between Group 1 and Group 2. The operation time was significantly shorter in Group 1 compared to the other groups (p < 0.017). The mean cement penetration depth across all groups was measured at 2.44 ± 0.27 mm. Bleeding volume and operation time did not have a significant effect on mean cement penetration (p > 0.05). Additionally, there were no significant differences observed between the groups in terms of the Lysholm and Oxford functional test results (p > 0.017). Conclusions: The use of a tourniquet was found to increase cement penetration and reduce operation time; however, it did not have a significant impact on reducing bleeding. Based on our findings, we recommend considering a shorter tourniquet time and implementing effective bleeding control measures to mitigate potential complications associated with tourniquet usage.

The Effect of Systolic Blood Pressure on Cement Penetration Depth in Primary Total Knee Arthroplasty

Background: Cement Penetration Depth (CPD) into bone is an important factor for successful Total Knee Arthroplasties (TKA). Our study investigated the effect of Systolic Blood Pressure (SBP) on average tibial, femoral and total CPD in primary TKA. Methods and Findings: In this retrospective cohort study, patients who had a primary TKA between November 2018 and February 2020 at four, academic medical centers were included. CPD was evaluated according to the Knee Society Radiographic Evaluation System on radiographs one month post-operatively. Two independent evaluators measured four zones of tibial penetration and three zones of femoral penetration and averaged their results. The measurements were combined to create an average tibial, average femoral and average total CPD. SBP was collected at the 3/4 time of surgery length- the estimated time of cementation. 1221 primary TKA cases were included in the study – 1128 in the tourniquet group and 93 in the tourniquet-less group. There were no significant differences between the age, sex, BMI, or LOS between the two cohorts. A multiple, multivariate analysis was performed. In the tourniquet-less group, SBP did not significantly affect average tibial CPD (p=0.98), average femoral CPD (p=0.45), or average total CPD (p=0.23). However, tourniquet use was found to significantly increase average femoral (p<0.001) and total penetration (p=0.001). Conclusion: SBP did not significantly affect tibial, femoral, or total CPD in patients undergoing tourniquet-less, primary TKA. However, the use of a tourniquet significantly aids in average femoral and total CPD. The clinical significance of this difference needs further investigation.

Pressurized carbon dioxide lavage reduces the incidence of a radiolucent line around the tibial component two years after total knee arthroplasty

IntroductionIn cemented total knee arthroplasty (TKA), pressurized carbon dioxide (CO2) lavage prior to cement fixation can eliminate debris at the bone-cement interface and is considered effective for increasing cement penetration and preventing aseptic loosening. Regarding the risk of a preliminary diagnosis of implant loosening, a radiolucent line (RLL) is a valuable sign. The purpose of this study was to compare the incidence of a tibial RLL at 2 years after TKA with and without pressurized CO2 lavage.MethodsThis is a retrospective study. One hundred knees from 98 patients were enrolled in this study. TKA was performed without pressurized CO2 lavage (CO2− group) for the first 47 knees, and with pressurized CO2 lavage (CO2+ group) for the next 53 knees. The depth of cement penetration was measured just after surgery, and the incidence of tibial RLL > 2 mm at 2 years after TKA was determined.ResultsSignificant differences between groups were not seen regarding pre- and postoperative clinical factors. The depth of cement penetration in each area was significantly higher in the CO2+ group. The frequency of knees with RLL > 2 mm was significantly lower in the CO2+ group than in the CO2− group (p < 0.001).ConclusionsPressurized CO2 lavage improved cement penetration and decreased the incidence of tibial RLL > 2 mm at 2 years after TKA.

Using suction in back-bleeding conditions increases cement penetration without the need for a tourniquet

BackgroundThe majority of total knee arthroplasties are performed with a tourniquet as it is perceived this gives rise to superior cement fixation. Tourniquets, however, have been associated with increased pain, post-operative swelling, and reduced knee range of movement which can all detrimentally impact patient recovery. This laboratory-based study aimed to assess if it is possible to achieve equivalent (or even enhanced) cementation without a tourniquet using a novel suction device. MethodsCement penetration was compared between conditions simulating bone with back-bleeding with and without the use of suction in open-cell rigid foam tibia models and porcine specimens. Suction was applied via a urinary catheter inserted into the tibial recess created for the implant's stem. Cement penetration depth was measured from micro-CT scans. The pull-off strength of cemented tibial implant analogues in porcine specimens with and without suction was also assessed. ResultsSuction gave rise to a significant (p = 0.028) increase in cement penetration depth in both the rigid foam, 5.4 – 6.6 mm, and porcine specimens, 0.7 – 1.0 mm. A non-significant increase in implant pull-off strength was also observed. ConclusionSuction during cementation in a back-bleeding model resulted in significantly greater cement penetration depth. Using suction surgeons can avoid potential disadvantages of tourniquet use without compromising cementation.

Pulsatile Lavage During Cementation of Total Knee Arthroplasty - Is Fixation Impaired? A Cadaver Study.

Increasing economic pressure in modern healthcare necessitates an increase in efficiency in total knee arthroplasty (TKA) while maintaining high-quality outcomes. Removal of debris using pulsatile lavage (PL) during cement polymerization may considerably reduce the operative duration. However, water can penetrate the interface, resulting in impaired implant fixation. The aim of the present study was to investigate the impact of early-onset PL during bone cement polymerization on implant fixation and operative duration. Cemented implantation of tibial trays was performed in 20 fresh-frozen human tibiae from 10 donors in a matched-pair study design in two groups: 1) PL during cement polymerization; and 2) PL after completion of the polymerization process. The cement penetration depth was analysed by computed tomography (CT), and the pull-out force was measured to evaluate primary implant fixation. The duration of the procedure was recorded for both groups. Comparable pull-out forces were observed in the experimental (2,213 N) and control groups (2,350 N; p=0.68). The mean depth of cement penetration was similar in both groups. PL during cement polymerization could decrease the operative duration by 10 min. The application of PL during cement polymerization could significantly reduce operative duration and had no adverse effect on the mechanical fixation of the tibial component.

Pulsatile Lavage Improves Tibial Cement Penetration and Implant Stability in Medial Unicompartmental Arthroplasty: A Cadaveric Study.

Cemented unicompartmental knee arthroplasty (UKA) shows good survivorship and function. However, implant failure, causing the need for revision, can occur. Aseptic loosening is still among the most common reasons for revision. The purpose of this study was to assess the influence of preimplantation lavage technique on tibial cement penetration depth, tibial cement volume, and load to fracture in the tibial component of mobile-bearing UKA. In 10 pairs of fresh frozen human tibiae, cemented UKA was implanted by an experienced surgeon. Tibial components were then implanted, left and right tibiae were randomly allocated to group A or B. Prior to implantation, irrigation was performed with either syringe lavage or pulsatile jet lavage in a standardized manner. Cement surface was 4170.2 mm2 (3271.6-5497.8 mm2) in the syringe lavage group, whereas the jet lavage group showed 4499.3 mm2 (3354.3-5809.1 mm2); cement volume was significantly higher as well (4143.4 mm3 (2956.6-6198.6 mm3) compared with 5936.9 mm3 (3077.5-8183.1 mm3)). Cement penetration depth was 2.5 mm (1.7-3.2 mm) for the jet lavage, and 1.8 mm (1.2-2.4 mm) for the syringe lavage. The mean fracture load was 4680 N in the jet lavage group and 3800 N in the syringe lavage group (p = 0.001). Subsidence was significantly higher for syringe lavage. This study suggests a correlation of cement penetration depth and cement volume to implant failure in the tibial component of a UKA using a cadaveric model. The type of bone lavage most likely influences these two key parameters.

High-Viscosity Versus a Lower-Viscosity Cement Penetration at Dough Phase In Vivo in Primary Total Knee Arthroplasty

BackgroundPrevious studies have shown that the depth of cement penetration and the presence of radiolucent lines (RLLs) correspond with the risk of aseptic loosening in total knee arthroplasty, while others have found a correlation between the viscosity of the cement and the depth of cement penetration. We compared cement marketed as high-viscosity cement (HVC) with one marketed by the same manufacturer as low-viscosity cement (LVC). We hypothesized that no significant difference would be found in depth of penetration or presence of RLLs between the two cohorts. MethodsThe HVC (n = 50) and LVC cohorts (n = 50) were gathered from two sequential series of primary total knee arthroplasties using the same implants and cementing techniques. Depth of cement penetration and presence of RLL were measured in four tibial zones and were compared between cohorts. ResultsThere were no cases of aseptic loosening in either cohort at a mean of 29 months. Mean maximum cement penetration in 3 of the 4 zones was >3 mm with both cements. There was no significant difference in maximum penetration in any zone between the two cements. There were fewer tibial radiolucencies with HVC than LVC. ConclusionThese findings suggest that the marketing description of HVC or LVC is not necessarily a factor in cement penetration. The term high viscosity should not be used as a descriptor of cement that reaches dough phase more quickly, but rather cement that has a higher viscosity at its dough phase when it is typically applied.

The Effect of Tranexamic Acid and Tourniquet Use on Tibial Cement Penetration in Primary Total Knee Arthroplasties.

BackgroundIn this study, our aim was to compare the effects of tourniquet and tranexamic acid (TXA) use on tibial cement penetration in primary total knee arthroplasty (TKA) using radiograph images. In addition, we also aimed at investigating the effects of age, gender, body mass index (BMI), and bone mineral density on cement penetration.MethodsOne hundred seventy patients who underwent TKA for primary osteoarthritis were retrospectively evaluated. TXA was administered to patients in group 1 (n = 96), and tourniquet application was used in patients in group 2 (n = 74). Tibial cement penetration was evaluated radiologically on a total of 4 zones: 2 anteroposterior and 2 lateral zones. In addition, age, gender, BMI, and bone mineral density were recorded in each group.ResultsThe mean cement penetration in the total study population was 2.34 ± 0.24 mm, with a mean of 2.33 ± 0.25 mm in the TXA group and a mean of 2.35 ± 0.24 mm in the tourniquet group (P = .453). A negative correlation was detected between BMI and anteroposterior 1 values in the total and TXA groups (P = .022 and P = .029). In the evaluation of the differences between genders, significantly higher penetration values were observed only in the females in the tourniquet group (P = .024).ConclusionsThe use of TXA instead of a tourniquet does not reduce the depth of cement penetration in TKA. The clinical implications of individual-induced penetration differences may be significant for future implant survival.

Aseptic Loosening at the Tibia in Total Knee Arthroplasty: A Function of Cement Mantle Quality?

BackgroundAseptic loosening remains one of the leading causes for failure of total knee arthroplasty (TKA). We sought to identify early radiographic measures that may associate with aseptic tibial component loosening, emphasizing systematic evaluation of the cement mantle. MethodsAll TKA revisions from 2007 to 2015 with the primary indication of tibial aseptic loosening were identified using in an institutional implant retrieval database. After exclusion criteria, 61 TKAs comprised the study group. A matched control group of 59 TKAs that had not failed at a minimum of 3 years was identified for comparison. Radiographic analysis on all 6-week postoperative radiographs included angulation of components, cement penetration depth, and presence of radiolucency at the implant-cement and bone-cement interfaces. Groups were compared with Student’s t-test, chi-squared test, and Mann-Whitney U-test. A final multivariable logistic regression model was formed for the outcome of aseptic loosening. ResultsOn multivariable analysis, failure was associated with a greater number of zones with cement penetration <2 mm (5.6 vs 3.4 zones, odds ratio [OR] 1.89, P < .001), increasing percent involvement of radiolucency at the implant-cement interface (8.7% vs 3.1%, OR = 1.15, P = .001), and increased varus alignment of the tibial component (1.5° vs 0°, OR = 1.35, P = .014). A greater number of zones with a radiolucent line at the bone-cement interface did not significantly associate (1.1 vs 0.3, P = .091). ConclusionOur results suggest that radiographic indicators of poor cement mantle quality associate with later aseptic loosening. This emphasizes the need for surgeons to perform careful cement technique in order to reduce the risk of TKA failure. Level of EvidenceIII (Case-control).

Influence of bone density on morphologic cement penetration in minimally invasive tibial unicompartmental knee arthroplasty: an in vitro cadaver study

BackgroundUnicompartmental knee arthroplasty is an established treatment option for anteromedial osteoarthritis. However, large registry studies report higher rates of aseptic loosening compared to total knee arthroplasty. The objective of this study was to assess the impact of bone density on morphological cement penetration. Moreover, an alternative regional bone density measuring technique was validated against the established bone mineral density assessment.MethodsComponents were implanted on the medial side of 18 fresh-frozen cadaver knees using a minimally invasive approach. Bone density has been quantified prior to implantation using Hounsfield units and bone mineral density. Morphological cement penetration has been assessed in different areas and was correlated with local bone density.FindingsA highly significant correlation between Hounsfield units and trabecular bone mineral density was detected (r = 0.93; P < 0.0001), and local bone density was significantly increased in the anterior and posterior area (P = 0.0003). The mean cement penetration depth was 1.5 (SD 0.5 mm), and cement intrusion into trabecular bone was interrupted in 31.8% (SD 23.7%) of the bone-cement interface. Bone density was correlated significantly negative with penetration depth (r = − 0.31; P = 0.023) and positive with interruptions of horizontal interdigitating (r = + 0.33; P = 0.014). Cement penetration around the anchoring peg was not significantly correlated with bone density.InterpretationAreas with high bone density were characterized by significantly lower penetration depths and significantly higher areas without cement penetration. Anchoring pegs facilitate cement intrusion mechanically. Regional quantification of bone density using Hounsfield units is a simple but valuable extension to the established determination of bone mineral density.

Accuracy of a non-invasive CT-based measuring technique for cement penetration depth in human tibial UKA

BackgroundAseptic loosening of the tibial component remains a major cause of failure in unicompartmental knee arthroplasty (UKA) and may be related to micro-motion at the cement-bone interface due to insufficient cement penetration depth. Cement penetration is therefore taken as an indicator of solid fixation strength and primary stability. However, its non-invasive clinical assessment remains difficult in vivo as conventional x-ray is prone to distortion and CT-scans (computed tomography) are difficult to assess due to metal artifacts. The purpose of this study was to develop and validate a reliable in vivo measuring technique of cement penetration depth in human tibial UKA.MethodsIn an experimental setting, twelve UKA were implanted in fresh-frozen human cadaver knees using a minimal-invasive medial approach. Cement penetration depth was then measured via 1) virtual 3D-models based on metal artifact reduced CT-scans and 2) histological evaluation of nine serial cross-section cuts through the implant-cement-bone-interface. Subsequently, a concordance analysis between the two measuring techniques was conducted.ResultsThe average cement penetration depth was 1) 2.20 mm (SD 0.30 mm) measured on metal artifact reduced CT-scans and 2) 2.21 mm (SD = 0.42) measured on serial cuts (p = 0.956). The mean difference between both techniques was 0.01 mm (SD 0.31 mm) and the Person correlation coefficient was r = 0.686 (p = 0.014). All differences were within the upper and lower limit of agreement. There was no evidence of any significant proportional bias between both techniques (p = 0.182).ConclusionsCT-based non-invasive measurement of cement penetration depth delivers reliable results in measuring the penetration depth in tibial UKA. Thereby, it enables clinicians and researchers to assess the cement penetration for in vivo diagnostics in the clinical setting as well as in vitro biomechanical research with subsequent application of load to failure on the implant-cement-bone-interface.

Dentin pretreatment with Er:YAG laser and sodium ascorbate to improve the bond strength of glass fiber post.

Root-filled teeth that received fiber posts most frequently fail at the adhesive interface between resin cement and dentin. The objective of this study is to evaluate the effect of Er:YAG laser and/or sodium ascorbate (SA) on bond strength, microhardness of dentin, and penetration depth of cement into dentinal tubules. Forty-eight bovine incisor roots were endodontically treated, post spaces were prepared and equally divided into four groups (n= 12): G1-distilled water (control); G2-10% SA (10min); G3-Er:YAG laser (150mJ/4Hz/40s), and G4-Er:YAG laser + 10% SA. Glass fiber posts were cemented and roots sectioned into slices. In the first slice, the push-out bond strength (MPa) and failures were analyzed by confocal laser scanning microscope (CLSM). The second slice was subjected to microhardness test (KHN) and CLSM to assess the cement penetration. ANOVA and Tukey test were used for bond strength and microhardness data and Kruskal-Wallis and Dunn tests for the cement penetration (α = .05). The SA-treated samples had higher bond strength (10.02 ± 5.45a), similar to Er:YAG laser (9.91 ± 4.62a) and Er:YAG laser + SA (8.09 ± 4.07a). The least values (P < .05) were found on control (4.02 ± 2.39b). Significant differences were observed on root thirds (P < .05): cervical > middle > apical. There was a predominance of adhesive failures. The microhardness test revealed no differences between groups (P > .05). The experimental groups (G2, G3, and G4) had highest penetration into dentinal tubules when compared to the control (G1). Dentin pretreatments with Er:YAG laser or SA improved bond strength of cement-post-dentin interfaces; however, no synergistic effect of both treatments combined was observed.

Effect of lavage and brush preparation on cement penetration and primary stability in tibial unicompartmental total knee arthroplasty: An experimental cadaver study

BackgroundUnicompartmental total knee arthroplasty (UKA) is a well-established treatment option for unicondylar osteoarthritis, and generally leads to better functional results than tricompartimental total knee arthroplasty (TKA). However, revision rates of UKAs are reported as being higher; a major reason for this is aseptic loosening of the tibial component due to implant–cement–bone interface fatigue. The objective of this study was to determine the effects of trabecular bone preparation, prior to implantation of tibial UKAs, on morphological and biomechanical outcomes in a cadaver study. MethodsCemented UKAs were performed in 18 human cadaver knees after the bone bed was cleaned using pulsed lavage (Group A), conventional brush (Group B) or no cleaning at all (Group C, control). Morphologic cement penetration and primary stability were measured. ResultsThe area proportion under the tibial component without visible cement penetration was significantly higher in Group C (21.9%, SD 11.9) than in both Group A (7.1%, SD 5.8), and Group B (6.5%, SD 4.2) (P=0.007). The overall cement penetration depth did not differ between groups. However, in the posterior part, cement penetration depth was significantly higher in Group B (1.9mm, SD 0.3) than in both Group A (1.3mm, SD 0.3) and Group C (1.4mm, SD 0.3) (P=0.015). The mode of preparation did not show a substantial effect on primary stability tested under dynamic compression-shear test conditions (P=0.910). ConclusionBone preparation significantly enhances cement interdigitation. The application of a brush shows similar results compared with the application of pulsed lavage.

The Influence of Cement Morphology Parameters on the Strength of the Cement-Bone Interface in Tibial Tray Fixation

BackgroundThe strength of the cement-bone interface in tibial component fixation depends on the morphology of the cement mantle. The purpose of this study was to identify thresholds of cement morphology parameters to maximize fixation strength using a minimum amount of cement. MethodsTwenty-three cadaveric tibiae were analyzed that had been implanted with tibial trays in previous studies and for which the pull-out strength of the tray had been measured. Specimens were separated into a group failing at the cement-bone interface (INTERFACE) and one failing in the bulk bone (BULK). Maximum pull-out strength corresponds to the ultimate strength of the bulk bone if the cement-bone interface is sufficiently strong. 3D models of the cement mantle in situ were reconstructed from computed tomography scans. The influences of bone mineral density and 6 cement morphology parameters (reflecting cement penetration, bone-cement interface, cement volume) on pull-out strength of the BULK group were determined using multiple regression analysis. The threshold of each parameter for classification of the specimens into either group was determined using receiver operating characteristic analysis. ResultsCement penetration exceeding a mean of 1.1 mm or with a maximum of 5.6 mm exclusively categorized all BULK bone failure specimens. Failure strength of BULK failure specimens increased with bone mineral density (R2 = 0.67, P < .001) but was independent of the cement morphology parameters. ConclusionTo maximize fixation strength, a mean cement penetration depth of at least 1.1 mm should be achieved during tibial tray cementing.

Thermal Analysis of the Tibial Cement Interface with Modern Cementing Technique.

Background:The major cause of cemented Total Knee Arthroplasty (TKA) failure is aseptic loosening of the tibial component necessitating revision surgery. Recently, multiple techniques have been described to maximize cement penetration depth and density in the proximal tibia during TKA to potentially avoid early loosening. While cement polymerisation is an exothermic reaction, minimal investigation into the proximal tibial thermal safety margin during cement polymerisation has been undertaken. In animal models osseous injury occurs at temperatures greater than 47 °C when applied for one minute. The aim of this study was to investigate the cement bone interface temperatures in TKA using modern tibial cementing techniques with a cadaveric tibial tray model. Methods:Eight adult cadavers were obtained with the proximal tibial surface prepared by a fellowship trained arthroplasty surgeon. Third generation cementation techniques were used and temperatures during cement polymerization on cadaveric knee arthroplasty models were recorded using thermocouples. Results:The results showed that no tibial cement temperature exceeded 44 °C for more than 1 minute. Two of the eight cadaveric tibias recorded maximum temperatures greater than 44 °C for 55 seconds and 33 seconds, just less than the 60 seconds reported to cause thermal injury. Average maximum polymerization temperatures did not correlate with deeper cement penetration or tray material. Maximum mantle temperatures were not statistically different between metal and all polyethylene tibial trays. Conclusion:Our investigation suggests that modern cementing techniques result in maximum mantle temperatures that are less than previously recorded temperatures required to cause thermal osseous injury, although this thermal injury safety margin is quite narrow at an average of 4.95 °C (95% confidence interval ± 4.31).

2016

The purpose of this study was to evaluate and compare the intrusion characteristics of Simplex-HV to Simplex-P and Palacos-R in cadaveric proximal tibial bone. Eighteen fresh-frozen cadaver proximal tibiae were examined with standard arthroplasty tibial cuts. Each tibia was randomly assigned to receive one of the three bone cements for use with finger packing technique. Sagittal sections were prepared and analyzed using digital photography and stereoscopic micrographs to evaluate cement intrusion characteristics. The cement penetration depth was measured from the tibial bone cut surface, which did not include the cement thickness under the tibial base plate. Significant differences were detected in the bone cement penetration between the three cements. Penetration was increased using the Simplex-HV (average, 2.7 mm; range, 2.0-3.0 mm) compared with Simplex-P (average, 2.2 mm) and Palacos-R (average, 1.8 mm). These depths approximate to 3.7, 3.2, and 2.8 mm of total cement penetration, respectively. The data suggest that high-viscosity bone cement may provide good fixation of the tibial component of a total knee arthroplasty when using the finger packing technique.

Finite element study of the acetabulum in cemented hip arthroplasty investigating retention or removal of the subchondral bone plate.

The importance of the subchondral bone plate of the acetabulum when preparing the pelvis for a cemented acetabular cup during total hip arthroplasty (THA) has been investigated using finite element analysis. The effect of retaining or removing the subchondral bone plate and the use of anchoring holes are compared. Loading was applied via both hip joint contact force and the activity of up to 22 muscles at five stages through the load bearing phase of the gait cycle. Removing the subchondral bone plate leads to decreased stresses in the cancellous bone and slightly increased stresses in the cortical shell superior to the acetabulum. The differences between the two cases are small, nevertheless there are indications that removal of the subchondral bone plate reduces the stresses. Increasing the cement penetration depth leads to a slightly more rigid structure, due to cement penetrating the cancellous bone. Adding anchoring holes moves the position of the highest cancellous bone strains from the bone-cement interface into the cancellous bone. Thus removal of the subchondral bone plate should lead to an increased potential for cement penetration into the cancellous bone which should be beneficial for cup fixation and thus improve long term implant survival.

Cement applicator use for hip resurfacing arthroplasty

We compared the manufacturer recommended cementing technique for a femoral hip resurfacing implant (BHR, S&N) to a newly designed cement applicator on 20 porous carbon foam specimens. Substantial design changes and improvements of the cement applicator were necessary: The diameter and number of the cement escaping holes at the top of the applicator were optimized for medium viscosity cement. It was necessary to add four separate air inlet holes with large diameters. The inner shape of the applicator had to be adapted to the BHR design with a circular extending chamfer in the proximal region, a parallel inner wall and a second chamfer distally.The interface temperatures showed no risk for heat necrosis using both techniques. The cement penetration depth was more uniform and significantly reduced for the applicator cementing technique (4.34 ± 1.42 mm, 6.42 ± 0.43 mm, p = 0.001). The cement-applicator showed no cement defects compared to a large defect length (0.0 ± 0.0 mm, 10.36 ± 1.10 mm, p < 0.001) with the manufacturer recommended cementing technique.The cement applicator technique appears to be effective for a homogenous cement distribution without cement defects and safe with a lower risk of polar over-penetration.

The effect of multiple drilling on a sclerotic proximal tibia during total knee arthroplasty.

To assess the depth of cement penetration and the occurrence of radiolucent line (RLL) according to drill bit diameter used in multiple drilling for the sclerotic bone of the medial proximal tibia during total knee arthroplasty (TKA). The multiple drilling procedure was performed with 2.0 mm diameter in group 1 (n = 290) and with 4.5 mm diameter in group 2 (n = 109) to enhance the cement penetration. The postoperative RLL in the cement-bone interface and the depth of cement penetration were measured under the tibial implant at three, six, 12 and 24 months after TKA. The progression of RLL was also evaluated at the latest follow-up. Cumulative occurrence rates of RLLs were significantly lower in group 2 than in group 1 at 12 and 24 months postoperatively (P = 0.005 and 0.004). The depth or width was increased in nine cases only in group 1 at the latest follow up. There was no tibial implant loosening in both groups at the latest follow-up. Mean maximal depths of cement penetration were 1.1 mm in group 1 and 4.8 mm in group 2 at three months (P < 0.001). Our comparative study between the different diameters used during multiple drilling for the tibial sclerotic surface suggests that a multiple drilling technique with a larger diameter of 4.5 mm can improve the depth of cement penetration and reduce the occurrence rate of RLLs after TKAs.

Mechanical properties of a cemented porous implant interface

Background — Revision arthroplasty often requires anchoring of prostheses to poor-quality or deficient bone stock. Recently, newer porous materials have been introduced onto the market as additional, and perhaps better, treatment options for revision arthroplasty. To date, there is no information on how these porous metals interface with bone cement. This is of clinical importance, since these components may require cementing to other prosthesis components and occasionally to bone.Methods — We created porous metal and bone cylinders of the same size and geometry and cemented them in a well-established standardized setting. These were then placed under tensile loading and torsional loading until failure was achieved. This permitted comparison of the porous metal/cement interface (group A) with the well-studied bone/cement interface (group B).Results — The group A interface was statistically significantly stronger than the group B interface, despite having significantly reduced depth of cement penetration: it showed a larger maximum tensile force (effect size 2.7), superior maximum tensile strength (effect size 2.6), greater maximum torsional force (effect size 2.2), and higher rotational stiffness (effect size 1.5).Interpretation — The newer porous implants showed good interface properties when cemented using medium-viscosity bone cement. The axial and rotational mechanical strength of a porous metal/cement interface appeared to be greater than the strength of the standard bone/cement interface. These results indicate that cementing of porous implants can provide great stability in situations where it is needed.