Snapform SimFit: Better sockets using a patient-specific simulation

Today most products are designed using simulation tools. Product engineers design and test new products, such as a new car model, virtually with advanced simulation tools before they build the car. The outcome is a better car designed much faster.  

Without these advanced simulation tools, we would not have the high-performance products that we have today. 

Until now such simulation tools have seen limited use in prosthetics design due to the complexity of the software and the difficulty of creating a simulation for each individual patient.

Snapform SimFit is changing that.  SimFit is the world first prosthetic design solution that automatically creates a patient-specific simulation directly from a 3D scan of the patient’s stump. The patient-specific simulation makes is possible to design the socket in a fast and intuitive way and, importantly, understand how the socket loads the stump when the patient is using the prosthesis.

A socket is today designed by changing the shape of the cast or scan via a trial-and-error process. The patient-specific simulation enables a better approach. The areas of the stump can be loaded with different levels of pressure commonly referred to as pressure sensitive and tolerant areas.  The patient-specific simulation allows the prosthetist to design directly by setting a design pressure.  It is possible to say I want more pressure here and less here. Making the design process more intuitive.

The Snapform SimFit workflow has three steps. In the model step SimFit automatically builds an anatomical and a finite element model of the stump from the 3D scan.

In the design step, the socket is shaped via a design pressure representing the pressure sensitive and tolerant areas known by every prosthetist.  SimFit automatically calculates a design proposal based on the anatomy. The prosthetist can modify this as needed.  

In the final simulation step SimFit calculates the socket shape using finite element analysis (FEA). FEA allows SimFit to calculate the socket shape from the design pressure.

In the simulation step SimFit also determines the skin pressure when the patient is standing on the prosthesis. This is again done using FEA where the body weight is applied to the socket. This allows the prosthetist to evaluate the design. Something that is impossible in a CAD workflow, where the prosthetist is left guessing about the fit.

The benefit is a much-reduced need for trial-and-error fitting and a better fitting socket. 

Snapform SimFit is particular useful for small stumps which are heavily loaded due to their size. This makes it challenging to make a good socket in a traditional workflow. Here SimFit is a great tool to provide a well-fitting socket to the patient.

Snapform SimFit is an open system. It does not lock you in by forcing you to produce socket in certain way. Snapform can provide a 3D printed socket, but you can also manufacture it yourself from the SimFit output data.