Frequently asked questions

You can use any scanner as long as you can output an .stl, .ply or .obj file. High quality structured light scanners tend to provide more reliable results, but many CPOs are getting great results with Your® Liner using less expensive iPad or iPhone-based scanners. Indeed, as liners are flexible, the need to have an extremely accurate scan is probably less crucial to obtaining good results as it may be for prosthetic sockets. Please note we prefer working with scans which include the colour. This allows to visually locate the indications drawn on the limb (e.g. location of measurements, drawn zones for thickness control)

GENERAL PRINCIPLES #1: Don't push-up the soft tissues We want soft tissues pulled down into the liner as much as possible to avoid pistoning. #2: Scanned shape = shape when donning To ensure proper liner fit, the scanned shape should be as close as possible to the shape the limb will have when the patient dons the liner. #3: Find a comfortable position If your patient moves, the scan has higher chances of being deformed or contain dimensional error. #4: Take 2 scans in different positions A standing (vertical limb) and a sitting scan (horizontal limb) can help us see how soft tissues move in different positions. This helps is rework the soft tissues best. SCANNING POSITIONS By order of preference: #1: Standing This allows soft tissues to hang down to limit pistoning. If patient can't stand still, move to: #2: Sitting Position your patient on a high support (high stool, corner of a table, height controlled bed) so it is easier to scan the distal and posterior areas. For AK patients, ensure the patient sits on the edge so the posterior area is visible to the fullest possible extent. #3: Scan positive from plaster cast If soft tissues make the shape impossible to properly scan, a cast can help control soft tissues to obtain viable shape. Important: position soft tissues as desired during casting, but do not rectify the positive (don't apply reductions) before scanning. IMPORTANT EXTRA TIPS Take videos! Show us how soft tissues move (palpating, pushing, moving the limb) and tell us more about the limb and it’s needs with your own words Scan with desired knee-flexion Re-working the knee flexion digitally can introduce errors. The best is to scan directly with the desired flexion angle you want the liner to have. Use a stocking if there are soft tissues Stockings are great to constrain soft tissues BUT they can hide concavities (scars, invaginations, surroundings of a bony prominence). In presence of abundant soft tissues, stockings are a must. If there are both soft tissues and concavities, take a scan with and a scan without the stocking.

Take the scan (and the measurements!) with the same flexion angle that you want the liner to have. When we need to correct the flexion angle of the liner, there is a risk that the obtained volume is modified and that compressions are not optimal. A bit of pre-flexion can lower the mechanical stress applied by the liner on the patella when sitting or when the knee is bent. However, a liner with too-much pre-flexion might create a fold on the patella when standing or when the knee is straight. Depending on the user activities, it might therefore be better to have a straight liner, or to have a bit of pre-flexion. Generally, we recommend having about 20° pre-flexion. We do not recommend having more than 40° pre-flexion. Also make sure to take the control measurements in the same position as the scan, as tissues can move and create a wrongful impression that the scan contains dimensional error, which might lead to a liner with unadapted compressions.

No ! We prefer raw scans. When cleaning / re-working your scan, some operations like smoothing out the scan can modify the overall volume, or modify some local shapes. As we provide a satisfaction warranty (we change the product on our costs if it doesn't fit), we prefer working from the original scan and measurements, so we can make sure all operations which are applied on the 3D model are done according to our quality standards. This way, if the liner doesn't work, there's no questions on whom to point the finger at... 😅 Furthermore, if you want to make sure we made adequate modifications on the scan, you can request a 3D model validation, where you can inspect the 3D model we made prior to launching the print.

#1: Find a suitable location Taking a 3D scan in an unadapted space can prove to be a rather frustrating experience. To avoid those: Make sure you have enough space to move around without being restricted. Check the lighting conditions: no direct exposure to sunlight, not too dark Check that the floor doesn't cause issues: some reflecting surfaces can cause issues with some scanning technologies, where the scanner can't detect the floor. #2: Calibrate and test your equipment beforehand Make sure to calibrate your scanner regularly! (If you have any questions about this, please feel free to contact us). Also, running a quick test to make sure your setup is working properly can avoid bad surprises on D day when the patient is in front of you. #3: Take control measurements Even highly experienced CPOs with the best scanners can sometimes get unexpected results. Patients can move, scanners can loose their references, calibration can be outdated, light conditions might impact scan quality... So to optimise the chances that the 1st liner fits great right away, we recommend taking extra control measurements so we can control the dimensions of the scan. Remember to draw directly on the limb the heights at which you took the measurements to ensure we can more accurately control your scan. #4: Ensure key areas of the scan aren't missing Small holes in the scan aren't a problem, as long as they are not located in a key area. It's of course better not to have any. But if you do, make sure that those holes are not located in key areas before you let your patient go. #5: Sit back and trust the process ! We're aware that prosthetics can sometimes be as much of an art as it is a science. That's why we not only have talented and experienced staff to deliver the optimal 3D model, but also a satisfaction warranty. If the 1st liner doesn't fit, we'll change it under warranty until we deliver the great liner we all want.