scholarly journals Removal of cement-augmented screws in distal femoral fractures and the effect of retained screws and cement on total knee arthroplasty: a biomechanical investigation

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Dirk Wähnert ◽  
Niklas Grüneweller ◽  
Boyko Gueorguiev ◽  
Thomas Vordemvenne ◽  
Dominic Gehweiler
Keyword(s):  
Bone Cement ◽  
Femoral Component ◽  
Knee Arthroplasty ◽  
Distal Femur ◽  
Implant Removal ◽  
Removal Torque ◽  
Pull Out ◽  
Screw Augmentation ◽  
Significant Difference ◽  
Screw Group

Abstract Background Given the increasing number of osteoporotic fractures of the distal femur, screw augmentation with bone cement is an option to enhance implant anchorage. However, in implant removal or revision surgeries, the cement cannot be removed from the distal femur without an extended surgical procedure. Therefore, the aims of this study were to investigate (1) whether cement augmentation has any influence on screw removal and removal torque, and (2) whether the implantation of a femoral component of a knee arthroplasty and its initial interface stability are affected by the remaining screws/cement. Material and methods Eight pairs of fresh-frozen human female cadaveric distal femurs (mean age, 86 years) with a simulated AO/OTA 33 A3 fracture were randomized in paired fashion to two groups and fixed with a distal femoral locking plate using cannulated perforated locking screws. Screw augmentation with bone cement was performed in one of the groups, while the other group received no screw augmentation. Following biomechanical testing until failure (results published separately), the screws were removed and the removal torque was measured. A femoral component of a knee arthroplasty was then implanted, and pull-out tests were performed after cement curing. Interference from broken screws/cement was assessed, and the maximum pull-out force was measured. Results The mean screw removal torque was not significantly different between the augmented (4.9 Nm, SD 0.9) and nonaugmented (4.6 Nm, SD 1.3, p = 0.65) screw groups. However, there were significantly more broken screws in in the augmented screw group (17 versus 9; p < 0.001). There was no significant difference in the pull-out force of the femoral component between the augmented (2625 N, SD 603) and nonaugmented (2653 N, SD 542, p = 0.94) screw groups. Conclusion The screw removal torque during implant removal surgery does not significantly differ between augmented and nonaugmented screws. In the augmented screw group, significantly more screws failed. To overcome this, the use of solid screws in holes B, C, and G can be considered. Additionally, it is possible to implant a femoral component for knee arthroplasty that retains the initial anchorage and does not suffer from interference with broken screws and/or residual cement. Level of Evidence 5

scholarly journals Cementing technique for total knee arthroplasty in cadavers using a pastry bone cement

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Hans Bösebeck ◽  
Anna-Maria Holl ◽  
Peter Ochsner ◽  
Manuel Groth ◽  
Kevin Stippich ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Bone Cement ◽  
Knee Arthroplasty ◽  
Primary Total Knee Arthroplasty ◽  
Pull Out ◽  
Ensure Patient Safety ◽  
Temperature Development ◽  
Total Knee ◽  
Primary Total Knee ◽  
Rule Out

Abstract Background In cemented primary total knee arthroplasty (TKA), aseptic loosening remains a major cause for failure. Cementing techniques and characteristics of a chosen cement play a key role for good fixation and implant survival. A pastry bone cement was developed to facilitate the cement preparation and to rule out most of preparation-associated application errors. The pastry bone cement was compared to a conventional polymethyl methacrylate cement in a TKA setting. Methods Standardized implantations of total knee endoprostheses were performed in bilateral knee cadavers to investigate handling properties, variables of cement application, working time, and temperature development. Mechanical aspects and cementation quality were assessed by pull-out trials and microscopic interface analysis. Results Both cements expressed similar characteristics during preparation and application, only the curing time of the pastry cement was about 3 min longer and the temperature peak was lower. Fractures of the conventional cement specimens differed from the pastry cement specimens in the tibial part, while no differences were found in the femoral part. Penetration depth of the pastry cement was similar (tibia) or deeper (femur) compared to the conventional cement. Conclusions The pastry cement facilitates the feasibility of cemented TKA. The pre-clinical tests indicate that the pastry bone cement fulfills the requirements for bone cement in the field of knee arthroplasty. A clinical trial is needed to further investigate the approach and ensure patient safety.

scholarly journals Correlation Between Asymmetric Resection of Posterior Femoral Condyles and Femoral Component Rotation in Total Knee Arthroplasty

2014 ◽  
Vol 2 (11_suppl3) ◽  
pp. 2325967114S0014
Author(s):  
Harun Reşit Güngör ◽  
Nusret Ök ◽  
Kadir Ağladıoğlu ◽  
Semih Akkaya ◽  
Esat Kıter
Keyword(s):  
Total Knee Arthroplasty ◽  
Femoral Component ◽  
Knee Arthroplasty ◽  
Trochlear Groove ◽  
Femoral Component Rotation ◽  
Component Rotation ◽  
Significant Difference ◽  
Total Knee ◽  
The Mean ◽  
The Asymmetry

Objectives: Pertaining to peculiar designs of current knee prostheses, more bone is removed from posteromedial femoral condyle than posterolateral condyle to obtain desired femoral component rotation. The aim of our study was to evaluate whether there is a correlation between the asymmetry of the cuts and the femoral component rotation in total knee arthroplasty. Methods: We built a model to simulate anterior chamfer cut (ACC) performed during total knee arthroplasty for measuring posterior condylar offset (PCO). Right knee axial MRI slices of a total 290 consecutive patients (142 male, 138 female, and mean age 31.39 ± 6.6) were examined. A parallel line to surgical transepiphyseal axis was drawn, and placed at the deepest part of trochlear groove. Posteromedial and posterolateral condylar offsets were measured by drawing perpendicular lines to ACC beginning from the intersection points of both anteromedial and anterolateral cortices to posterior joint line (PJL), respectively. Differences between posteromedial and posterolateral PCO were calculated, and femoral rotation angles (FRA) relative to PJL were measured. Results: The mean surgical FRA was 4.76 ± 1.16 degrees and the mean PCO differencesss- was 4.35 ± 1.04 mm for the whole group and there was no statistically significant difference between genders. There was a strong correlation between surgical FRA and PCO difference (p<0.0001, r=0.803). Linear regression analyses revealed that 0.8 mm of difference between the anteroposterior dimensions of medial and lateral PCO corresponds to 1 degree of surgical FRA (p<0.0001, R2=0.645). Conclusion: Correlation between the asymmetry of posterior chamfer cuts and achieved femoral component rotation can verify the accuracy of desired rotation, intraoperatively. However, further clinical investigations should be planned to test the results of our morphometric study.

scholarly journals The comparison of femoral component rotation in the total knee arthroplasty

2017 ◽  
Vol 17 (3) ◽  
pp. 24-31
Author(s):  
M Chmurny ◽  
S Krivanek ◽  
M Melisik ◽  
M Rovnak ◽  
L. Necas
Keyword(s):  
Total Knee Arthroplasty ◽  
Femoral Component ◽  
Knee Arthroplasty ◽  
Significance Level ◽  
Femoral Component Rotation ◽  
Gap Technique ◽  
Component Rotation ◽  
Significant Difference ◽  
Total Knee ◽  
Balanced Gap Technique

Abstract Introduction Background: Optimal femoral component rotation in total knee arthroplasty (TKA) is crucial to establish a balanced knee reconstruction. Unbalanced knees can lead to instability, patellofemoral problems, persistent pain, stiffness, and generally poorer outcomes including early failure. There are several methods to achieve the femoral component rotation such as balanced gap technique, measured resection technique, and bone landmarks such as transepicondylar line (TEA) and Whiteside line. The purpose of this study was to compare the balan ced gap technique with the TEA technique. Materials and Methods: This randomised prospective study compares the femoral component rotation obtained with the use of balanced gap technique and the TEA, as well as compares the differences due to preoperative knee desaxations. The study includes 50 knees, 19 with neutral alignment, 22 with varus, and 9 with valgus desaxation. The femoral component rotation was measured postoperatively on photodocumentation taken after determining the TEA and balanced gap technique line peroperatively. These lines were compared to the posterior femoral condyles obtaining the degree of rotation. In case of transepicondylar line it is condylar twist angle (CTA) and in case of ligament balancer rotation axis it is ligament balancer angle (LBA). Results: The statistically significant differences in femoral component rotation using the techniques mentioned above as well as differences in individual knee desaxations were observed. The average LBA was 3.42 degrees and average CTA 3.58 in neutral knees group, but in the varus knees the average CTA value was 2.27 degrees and LBA value was 1.05 degrees. The average CTA value in patients with valgus desaxation is 4.78 degrees and LBA value is 5.22 degrees. According to Tukey Post Hoc test a statistically significant difference in LBA value is between neutral and varus knees with a significance level of p = 0.000022 and the most significant difference between varus and valgus knees with a significance level of p = 0.000011. Conclusion: The statistically significant differences in femoral component rotation using the techniques mentioned above as well as differences in individual knee desaxations were observed.

Robot-Assisted Unicompartmental Knee Arthroplasty: Increasing Surgical Accuracy? A Cadaveric Study

2019 ◽  
Author(s):  
Magaly Iñiguez ◽  
Roberto Negrín ◽  
Jaime Duboy ◽  
Nicolás O. Reyes ◽  
Rodrigo Díaz
Keyword(s):  
Femoral Component ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Functional Results ◽  
Tibial Slope ◽  
Clinical Results ◽  
Robot Assisted ◽  
Post Surgery ◽  
Unicompartmental Knee ◽  
Significant Difference

AbstractUnicompartmental knee arthroplasty (UKA) represents 10% of knee arthroplasties. Advantages are better functional results, quicker recovery, shorter hospitalization time, and lower blood loss, among others. However, revision rates are larger than total knee arthroplasty. Among the most important factors that explain this are the implant position and alignment, and the correct surgical indication. Greater accuracy in the implant placement may improve clinical results and increase the rate of implant survival. The objective of this study is to evaluate the precision of the Navio robot-assisted system in the position and alignment of medial UKA compared with the conventional technique. This is an experimental pilot study. Twenty-six cadaveric models were randomized into 2 groups: Robot-Assisted surgery (R) and Conventional Surgery (C). Radiological study was performed pre- and post-surgery, evaluating the medial distal femoral angle (MDFA), medial proximal tibial angle (MPTA), tibial slope, tibiofemoral angle (TFA), sagittal femoral angle (SFA), and size of the femoral and tibial components. The main result measurement was the change in postoperative angulation. The results of this study are MDFA median of 1.07° (0.19–4.5) for group R and 0.12° (0.03–10.4) with a significant difference in variances; a Welch t-test of p = 0.013; and an MPTA of 1.28° (0.05–5.87) for R and 1.3°(0.08–14.1) for C with significantly different variances (p = 0.0064). Size of the femoral component has a difference of p < 0.05 between groups. No differences for dispersion of TFA nor for the size of the tibial component were observed. In conclusion, using robot-assisted UKA allows for greater accuracy in the positioning of the implants and in the prediction of the size of the femoral component.

Biomechanical Investigation of the Retrograde Intramedullary Nail Fixation for Distal Femoral Periprosthetic Fracture after Total Knee Arthroplasty

2014 ◽  
Vol 684 ◽  
pp. 389-394
Author(s):  
Ching Lung Tai ◽  
Pei Yi Liao ◽  
Wei Yang Peng
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Intramedullary Nail ◽  
Statistical Difference ◽  
Testing Machine ◽  
Periprosthetic Fractures ◽  
Retrograde Intramedullary Nail ◽  
Significant Difference ◽  
Total Knee ◽  
Screw Group

This study investigated the effect of fixation screw number of intramedullary nail on the postoperative stability of the femoral construct in treatment of periprosthetic fractures after total knee arthroplasty. With use of a material testing machine, both compressive and torsion tests were conducted to evaluate the biomechanical behavior of intact, and femora with periprosthetic fractures treated with retrograde intramedullary nail with 5-screw and 9-screw fixations. The results indicated the followings: 1) the average compressive stiffness for intact, 5-screw and 9-screw groups were 1,159±61.7, 950.6±18.6 and 958.2±26.1 N/mm, respectively. No statistical difference was found between 5-screw and 9-screw groups (p>0.05). However, significant difference was found between intact/5-screw and intact/9-screw groups (p<0.05). 2). the average torsion stiffness for intact, 5-screw group and 9-screw group were 5,527±71.2, 2,652±35.4 and 2,858±81.7 N*mm/Degree, respectively. Statistical difference was found between each other groups (p<0.05).

scholarly journals Biomechanical Analysis of Cortical Bone Trajectory Screw Versus Bone Cement Screw for Fixation in Porcine Spinal Low Bone Mass Model

2021 ◽  
Author(s):  
Yifan Li ◽  
Wei Xu ◽  
Silian Wang ◽  
Liwei Chen ◽  
Zhangpeng Shi ◽  
...  
Keyword(s):  
Bone Mass ◽  
Bone Cement ◽  
Cortical Bone ◽  
Axial Rotation ◽  
Low Bone Mass ◽  
Cortical Bone Trajectory ◽  
Pull Out ◽  
Significant Difference ◽  
Flexion Extension ◽  
Insertional Torque

Abstract PurposeTo compare the biomechanics of cortical bone trajectory screw(CBT) and bone cement screw(BC) in isolated porcine spinal low bone mass model.MethodTen porcine spines with 3 segments were treated with EDTA decalcification. After 8 weeks, all the models met the criteria of low bone mass.Ten specimens were randomly divided into two groups, one group was implanted with CBT screw(CBT group) and the other group was implanted with bone cement screw(BC group).The biomechanical material testing machine was used to compare the porcine spine activities of the two groups in flexion, extension, bending and axial rotation, and then insertional torque,pull-out force and anti-compression force of two groups were compared.Independent-sample t test was used for comparison between groups.ResultTen 3 segments porcine spine models with low bone mass were established, the bone mineral density of all models was lower than 0.75g/cm2. The flexion, extension, bending and axial rotation angle of CBT group and BC group respectively were 7.1±1.3°,4.3±0.8°,3.4±0.8°,6.8±0.7°and 6.4±0.8°,4.5±0.5°,3.5±0.5°,6.8±0.8°,there was no significant difference between the two groups,P＞0.05.However, there were significant differences between the two groups and the control group,P＜0.01.The insertional torque of the CBT group and BC group respectively were 0.43±0.09N-m and 0.30±0.07N-m (P=0.03), and the screw pull-out force were 462.67±72.51N and 325.60±77.27N (P=0.021), respectively. There were significant differences between the two groups.The anti-compression forces between the two groups were 3561.81±522.7N and 3586.80±607.42N, respectively, and there was no significant difference between the two groups (P =0.946).ConclusionThe insertional torque and pull-out force of the CBT were higher than those of the BC in the isolated low bone porcine spine model, and the range of motion and anti-compression ability of model were similar between the two fixation methods.

scholarly journals Biomechanical Analysis of Cortical Bone Trajectory Screw Versus Bone Cement Screw For Fixation In Porcine Spinal Low Bone Mass Model

2021 ◽  
Author(s):  
Yifan Li ◽  
Wei Xu ◽  
Silian Wang ◽  
Liwei Chen ◽  
Zhangpeng Shi ◽  
...  
Keyword(s):  
Bone Mass ◽  
Bone Cement ◽  
Cortical Bone ◽  
Axial Rotation ◽  
Low Bone Mass ◽  
Mass Model ◽  
Pull Out ◽  
Significant Difference ◽  
Flexion Extension ◽  
Insertional Torque

Abstract Purpose: To compare the biomechanics of cortical bone trajectory screw(CBT) and bone cement screw(BC) in isolated porcine spinal low bone mass model.Method: Ten porcine spines with 3 segments were treated with EDTA decalcification. After 8 weeks, all the models met the criteria of low bone mass. Ten specimens were randomly divided into two groups, one group was implanted with CBT screw(CBT group) and the other group was implanted with bone cement screw(BC group).The biomechanical material testing machine was used to compare the porcine spine activities of the two groups in flexion, extension, bending and axial rotation, and then insertional torque, pull-out force and anti-compression force of two groups were compared. Independent-sample t test was used for comparison between groups.Result: Ten 3 segments porcine spine models with low bone mass were established, the bone mineral density of all models was lower than 0.75g/cm2. The flexion, extension, bending and axial rotation angle of CBT group and BC group respectively were 7.1±1.3°,4.3±0.8°,3.4±0.8°,6.8±0.7°and 6.4±0.8°, 4.5±0.5°, 3.5±0.5°, 6.8±0.8°, there was no significant difference between the two groups,P＞0.05.However, there were significant differences between the two groups and the control group,P＜0.01.The insertional torque of the CBT group and BC group respectively were 0.43±0.09N-m and 0.30±0.07N-m (P=0.03), and the screw pull-out force were 462.67±72.51N and 325.60±77.27N (P=0.021), respectively. There were significant differences between the two groups. The anti-compression forces between the two groups were 3561.81±522.7N and 3586.80±607.42N, respectively, and there was no significant difference between the two groups (P =0.946).Conclusion: The insertional torque and pull-out force of the CBT were higher than those of the BC in the isolated low bone porcine spine model, and the range of motion and anti-compression ability of model were similar between the two fixation methods.

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