Using a Finite Element Model to Help Develop a Method to Test Knee Femoral Components

2008 ◽  
Author(s):  
Barbara J. Kralovic ◽  
Fred A. Wentorf ◽  
Dan L. Levine
Keyword(s):  
Total Knee Arthroplasty ◽  
Femoral Component ◽  
Distal Femur ◽  
New Technologies ◽  
Element Model ◽  
Success Rates ◽  
New Materials ◽  
Thigh Bone ◽  
Total Knee ◽  
And Cartilage

In total knee arthroplasty (TKA), the knee femoral component replaces the bone surfaces and cartilage on the distal femur (thigh bone) that have been damaged due to injury or disease. While success rates are high with TKA, some fractures of the femoral component have occurred clinically (Fig. 1 and 2) [1]. Understanding the nature of these fractures is critical since the industry is moving towards bone conserving designs, minimally invasive approaches, new materials and new technologies for TKA. At the same time patient requirements are changing as patients are heavier, younger, and more active.

Is bone density in the distal femur affected by use of cement and by femoral component design in total knee arthroplasty?

1999 ◽  
Vol 4 (3) ◽  
pp. 180-186 ◽  
Author(s):  
Takahiro Seki ◽  
Go Omori ◽  
Yoshio Koga ◽  
Yoshihiro Suzuki ◽  
Yoshinori Ishii ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Bone Density ◽  
Femoral Component ◽  
Knee Arthroplasty ◽  
Distal Femur ◽  
Component Design ◽  
Total Knee

scholarly journals Appropriate determination of the surgical transepicondylar axis can be achieved following distal femur resection in navigation-assisted total knee arthroplasty

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Sang Jun Song ◽  
Hyun Woo Lee ◽  
Kang Il Kim ◽  
Cheol Hee Park
Keyword(s):  
Total Knee Arthroplasty ◽  
Femoral Component ◽  
Knee Arthroplasty ◽  
Distal Femur ◽  
Ct Images ◽  
Level Of Evidence ◽  
Transepicondylar Axis ◽  
Imageless Navigation ◽  
Before And After ◽  
Total Knee

Abstract Background Many surgeons have determined the surgical transepicondylar axis (sTEA) after distal femur resection in total knee arthroplasty (TKA). However, in most navigation systems, the registration of the sTEA precedes the distal femur resection. This sequential difference can influence the accuracy of intraoperative determination for sTEA when considering the proximal location of the anatomical references for sTEA and the arthritic environment. We compared the accuracy and precision in determinations of the sTEA between before and after distal femur resection during navigation-assisted TKA. Methods Ninety TKAs with Attune posterior-stabilized prostheses were performed under imageless navigation. The sTEA was registered before distal femur resection, then reassessed and adjusted after distal resection. The femoral component was implanted finally according to the sTEA determined after distal femur resection. Computed tomography (CT) was performed postoperatively to analyze the true sTEA (the line connecting the tip of the lateral femoral epicondyle to the lowest point of the medial femoral epicondylar sulcus on axial CT images) and femoral component rotation (FCR) axis. The FCR angle after distal femur resection (FCRA-aR) was defined as the angle between the FCR axis and true sTEA on CT images. The FCR angle before distal resection (FCRA-bR) could be presumed to be the value of FCRA-aR minus the difference between the intraoperatively determined sTEAs before and after distal resection as indicated by the navigation system. It was considered that the FCRA-bR or FCRA-aR represented the differences between the sTEA determined before or after distal femur resection and the true sTEA, respectively. Results The FCRA-bR was −1.3 ± 2.4° and FCRA-aR was 0.3 ± 1.7° (p < 0.001). The range of FCRA-bR was from −6.6° to 4.1° and that of FCRA-aR was from −2.7° to 3.3°. The proportion of appropriate FCRA (≤ ±3°) was significantly higher after distal femur resection than that before resection (91.1% versus 70%; p < 0.001). Conclusions The FCR was more appropriate when the sTEA was determined after distal femur resection than before resection in navigation-assisted TKA. The reassessment and adjusted registration of sTEA after distal femur resection could improve the rotational alignment of the femoral component in navigation-assisted TKA. Level of evidence IV.

Isolated Liner Revision for Total Knee Arthroplasty Instability: A Road That Should Remain Less Taken

2020 ◽  
Author(s):  
Jason D. Tegethoff ◽  
Rafael Walker-Santiago ◽  
William M. Ralston ◽  
James A. Keeney
Keyword(s):  
Total Knee Arthroplasty ◽  
Femoral Component ◽  
Knee Arthroplasty ◽  
Primary Total Knee Arthroplasty ◽  
P Value ◽  
Surgical Morbidity ◽  
Exact Test ◽  
Total Knee ◽  
Component Revision

AbstractIsolated polyethylene liner exchange (IPLE) is infrequently selected as a treatment approach for patients with primary total knee arthroplasty (TKA) prosthetic joint instability. Potential advantages of less immediate surgical morbidity, faster recovery, and lower procedural cost need to be measured against reoperation and re-revision risk. Few published studies have directly compared IPLE with combined tibial and femoral component revision to treat patients with primary TKA instability. After obtaining institutional review board (IRB) approval, we performed a retrospective comparison of 20 patients treated with IPLE and 126 patients treated with tibial and femoral component revisions at a single institution between 2011 and 2018. Patient demographic characteristics, medical comorbidities, time to initial revision TKA, and reoperation (90 days, <2 years, and >2 years) were assessed using paired Student's t-test or Fisher's exact test with a p-value <0.01 used to determine significance. Patients undergoing IPLE were more likely to undergo reoperation (60.0 vs. 17.5%, p = 0.001), component revision surgery (45.0 vs. 8.7%, p = 0.002), and component revision within 2 years (30.0 vs. 1.6%, p < 0.0001). Differences in 90-day reoperation (p = 0.14) and revision >2 years (p = 0.19) were not significant. Reoperation for instability (30.0 vs. 4.0%, p < 0.001) and infection (20.0 vs. 1.6%, p < 0.01) were both higher in the IPLE group. IPLE does not provide consistent benefits for patients undergoing TKA revision for instability. Considerations for lower immediate postoperative morbidity and cost need to be carefully measured against long-term consequences of reoperation, delayed component revision, and increased long-term costs of multiple surgical procedures. This is a level III, case–control study.

scholarly journals Accuracy of total knee arthroplasty using the modified gap technique based on the bone gap: an evaluation of the bone gap with a distal femoral trial component

Arthroplasty ◽  
2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Goki Kamei ◽  
Shigeki Ishibashi ◽  
Koki Yoshioka ◽  
Satoru Sakurai ◽  
Hiroyuki Inoue ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Distal Femur ◽  
Gap Size ◽  
Flexion Gap ◽  
Gap Technique ◽  
Joint Gap ◽  
Total Knee ◽  
The Mean

Abstract Background In total knee arthroplasty (TKA) using the modified gap technique, the soft-tissue balance is measured after osteotomy of the distal femur and proximal tibia (conventional bone gap). However, after osteotomy, the flexion gap size during 90° knee flexion may be larger than that observed after implantation. The tension of the lateral compartment during 90° flexion may also be reduced after osteotomy of the distal femur. We manufactured a distal femoral trial component to reproduce the condition after implantation and prior to posterior condyle osteotomy. This study aimed to evaluate the effect of the trial component on the flexion gap. Methods This prospective study included 21 consecutive patients aged 78 years with medial osteoarthritis who underwent cruciate-retaining TKA between February 2017 and March 2018. The postoperative flexion gap size and inclination during 90° flexion were compared between cases with and without the trial component. Results The mean joint gap size with the trial component (13.4 ± 0.80 mm) was significantly smaller than that without the trial component (14.7 ± 0.84 mm). The mean gap inclination angle with the trial component (3.7° ± 0.62°) was significantly smaller than that without the trial component (5.5° ± 0.78°). Conclusions In the present study, the joint gap size and medial tension were significantly reduced after the trial component had been set. Accurate measurement of the soft-tissue balance is an important factor in the modified gap technique, and this method using a distal femoral trial component can offer better outcomes than those achieved with conventional methods.

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