Preoperative rotational assessment of the distal femur with CT may cause femoral component malrotation in TKA

The Knee ◽  
2021 ◽  
Vol 33 ◽  
pp. 24-30
Author(s):  
Min Wook Kang ◽  
Yong Tae Kim ◽  
Jong Hwa Lee ◽  
Joon Kyu Lee ◽  
Joong Il Kim
Keyword(s):  
Femoral Component ◽  
Distal Femur

Long-term competing risks for overall and cause-specific failure of rotating-hinge distal femoral arthroplasty for tumour reconstruction

2021 ◽  
Vol 103-B (8) ◽  
pp. 1405-1413
Author(s):  
Koichi Ogura ◽  
Tomohiro Fujiwara ◽  
Carol D. Morris ◽  
Patrick J. Boland ◽  
John H. Healey
Keyword(s):  
Aseptic Loosening ◽  
Femoral Component ◽  
Distal Femur ◽  
Quadriceps Muscle ◽  
Competing Risk ◽  
Implant Fixation ◽  
Bone Implant ◽  
Rotating Hinge ◽  
Rotating Hinge Knee

Aims Rotating-hinge knee prostheses are commonly used to reconstruct the distal femur after resection of a tumour, despite the projected long-term burden of reoperation due to complications. Few studies have examined the factors that influence their failure and none, to our knowledge, have used competing risk models to do so. The purpose of this study was to determine the risk factors for failure of a rotating-hinge knee distal femoral arthroplasty using the Fine-Gray competing risk model. Methods We retrospectively reviewed 209 consecutive patients who, between 1991 and 2016, had undergone resection of the distal femur for tumour and reconstruction using a rotating-hinge knee prosthesis. The study endpoint was failure of the prosthesis, defined as removal of the femoral component, the tibial component, or the bone-implant fixation; major revision (exchange of the femoral component, tibial component, or the bone-implant fixation); or amputation. Results Multivariate Fine-Gray regression analyses revealed different hazards for each Henderson failure mode: percentage of femoral resection (p = 0.001) and extent of quadriceps muscle resection (p = 0.005) for overall prosthetic failure; extent of quadriceps muscle resection (p = 0.002) and fixation of femoral component (p = 0.011) for type 2 failure (aseptic loosening); age (p = 0.009) and percentage of femoral resection (p = 0.019) for type 3 failure (mechanical failure); and type of joint resection (p = 0.037) for type 4 (infection) were independent predictors. A bone stem ratio of > 2.5 reliably predicted aseptic loosening. Conclusion We identified independent risk factors for overall and cause-specific prosthetic failure after rotating-hinge knee distal femoral arthroplasty using a competing risk Fine-Gray model. A bone stem ratio > 2.5 reliably predicts aseptic loosening. An accurate knowledge of the risks of distal femoral arthroplasty after resection for tumour assists surgical planning and managing patient expectations. Cite this article: Bone Joint J 2021;103-B(8):1405–1413.

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

Design and Simulation of a Femoral Component Peg in Total Knee Replacement

2010 ◽  
Vol 450 ◽  
pp. 111-114 ◽  
Author(s):  
Chang J. Wang ◽  
Jun F. Shi ◽  
Colin Morgan ◽  
Diane J. Mynors
Keyword(s):  
Total Knee Replacement ◽  
Femoral Component ◽  
Knee Replacement ◽  
Distal Femur ◽  
Bone Remodelling ◽  
Stress Shielding ◽  
Correct Placement ◽  
Cause Of Failure ◽  
Total Knee ◽  
Improve Stability

Aseptic loosening of the femoral component is one cause of failure in total knee replacement (TKR). Inadequate bone stock in the distal femur after TKR, due to the stress shielding, was often found in revision of the femoral component. The pegs in the femoral component are used as an aid to the correct placement of the component but they also help to transfer the load to the diaphyseal part of the bone and improve stability. This paper investigates the influence of femoral component peg design on stress distribution and bone remodelling in the distal femur after TKR. Eight different peg designs were investigated and reported in this paper. The bone remodelling parameters in the distal femur are presented, compared and analysed. Results show that a slender peg is advantageous in TKR.

Anatomical Assessment of Distal Femur for Optimal Femoral Component Rotational Alignment in TKA

2005 ◽  
Vol 40 (7) ◽  
pp. 882 ◽  
Author(s):  
Chong Bum Chang ◽  
Sang Cheol Seong ◽  
Sahnghoon Lee ◽  
Jae Ho Yoo ◽  
Seung Hwan Rhee ◽  
...  
Keyword(s):  
Femoral Component ◽  
Distal Femur ◽  
Rotational Alignment

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

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