The influence of “kickstand” screws on the mechanical performance of a lateral distal femoral plate

Listen to Simon and Amy discuss the paper 'The influence of “kickstand” screws on the mechanical performance of a lateral distal femoral plate' published in the August 2025 issue of Bone & Joint Research.

Click here to read the paper.

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Transcript

[00:00:00] Welcome back to another episode of AI Talks with Bone & Joint from the publishers of Bone & Joint Research. Today we're discussing the paper, 'The influence of “kickstand” screws on the mechanical performance of a lateral distal femoral plate', published in August 2025 by A Trompeter, A Christen, C Gerber, B Hofstaetter, F Wipf, and J Lowe.

I'm Simon and I'm joined by my co-host Amy. 

Hello everyone. This is Amy. Simon, I must say this paper delves into some truly intriguing biomechanical engineering. Let's start by summarizing why this research was conducted. Why did these researchers zero in on kickstand screws and their impact on distal femoral plates?

An excellent question, Amy. Essentially, lateral locked plating of distal femoral fractures is a well-established technique, but there's a notable incidence of mechanical failure ranging from 9% to 19%. The researchers aimed to determine if adding obliquely directed kickstand screws could improve the construct stiffness and reduce these failures. 

Precisely. [00:01:00] They utilized a finite element analysis bone defect model to compare the maximum stresses and forces on the plate and screws both with and without the additional kickstand screws. This type of analysis is ideal for predicting how design alterations will affect mechanical performance without the need for numerous physical tests.

Indeed. So let's discuss the methods they used. The study involved creating a finite element analysis model of a lateral based femoral plate with a simulated fracture gap. Parameters for bone material, the implant and composite models were identified. 

Yes, and they tested several variables. They added different configurations of kickstand screws, none, just the lower, just the upper, and both upper and lower kickstand screws. They then measured the principle stresses in the plate and screws and the locking forces at the screw plate joint interfaces. 

What I found particularly intriguing were the results. The addition of the upper kickstand screw, or both kickstand screws resulted in approximately a 40% reduction in stress in the [00:02:00] metaphyseal hole closest to the fracture. That's a significant finding.

Absolutely. For the screws themselves adding the kickstand screws reduced maximum stresses in the metaphyseal screws by 23%, with the lower 32% with the upper, and 34% with both. This is very promising for reducing mechanical failure. 

Also very relevant, is that the forces experienced by the locking mechanism significantly decreased. Adding the lower kickstand screw led to a 19% reduction in maximum forces, and the upper or both kickstand screws led to a 23% reduction. Again, a notable improvement. 

Simon, this has clear clinical implications, doesn't it? Surgeons frequently face mechanical failures, especially with complex fractures. These findings suggest that using kickstand screws could potentially improve patient outcomes by reducing the likelihood of early mechanical failures. 

They do, indeed. The study even mentions that despite technological advances in plate and screw design, challenges such as bending moments and various loading of [00:03:00] distal femoral constructs still exist. The kickstand screws could represent an evolution in managing these challenges. 

And it's worth noting the study's strengths and limitations. The finite element analysis model was well validated with in vitro testing and regulatory standards. Though it did not account for the soft-tissue envelope which can influence construct behavior. 

That's a fair point. Even though the finite element analysis model was robust, real life surgical outcomes can still vary. However, the overall conclusion was clear. The addition of kickstand screws significantly improves the mechanical performance of the lateral distal femoral plating construct. 

In summary, the research shows that adding kickstand screws can reduce stress and forces on both plates and screws, offering a potentially more reliable approach to managing distal femoral fractures. It's a very exciting development for orthopaedic trauma. 

That's a wrap for today's episode. Thank you all for tuning into AI Talks with Bone & Joint. We hope you found this discussion as intriguing as we did. [00:04:00] 

Thanks everyone. Goodbye for now.