Frequently asked questions

Pear-shaped limbs are limbs which present a prominence in a given area, and a narrower section in a more proximal area. Because of this, the limb can't be easily inserted into a classical prosthetic socket. Compensation liners are liners which include extra buildup in some areas to give a cylindrical shape once the liner is donned onto a limb.

Depending on the shape of the limb, a compensation liner might present buildups which are too extreme, and make the resulting liner too thick and therefore impossible to roll onto the limb. On the contrary, if using a liner with zero compensation for a pear-shaped limb, the fabric might not be able to stretch enough to allow for the thin segment of the liner to go over the larger distal segment of the limb when rolling the liner on. Several design parameters can be adjusted to facilitate donning, such as the used material, the applied reductions, or the suspension system. MotionTech has developed an algorithm which can calculate the strength required to don & doff a liner, based on a given stump shape and the design choices. Depending their abilities (e.g. hand strength), different users will or won't be able to don a liner which requires a given strength value. We can advise you on such cases ! Simply submit a classical order and write a comment asking for a "donning & doffing validation" prior to launching the print. We'll get in touch once the analysis is conducted to discuss the best options.

When we compensate a pear-shaped stump, we follow a simple rule: A given perimeter can not be more than 0.5cm smaller than any other more distal perimeter You have ordered a compensated liner, and when trying it on the patient you measure more than this difference ? There can be several explanations: #1 - Is the liner stretched vertically ? When rolling a compensated liner on the limb, the inside surface stretches out right before it comes in contact with the skin, which gradually stretches out the liner in the longitudinal direction when donning. This is accentuated by the thick pear-shape compensation pads. This can typically occur for ankle disarticulation cases (e.g. Symes). This vertical stretching leads to the designed thicknesses not being located where they are intended, which can result in an unsuitable pear-shape compensation. You can check if the liner is stretched vertically on the limb by measuring the length of the liner between distal end and a reference point of your choice when relaxed and when donned. To counter this longitudinal stretching effect, ensure you release the tension iteratively when you don the liner, as shown below: https://static.wixstatic.com/media/f1b417_fac3291d649a4db3afcc4e798c346bfc~mv2.gif Alternatively, you can apply cream on the limb prior to donning, to prevent the inner silicone surface from sticking to the skin, so the liner can get back to its natural length. #2 - You tried the above and it still doesn't work ? The error might then come from somewhere else. This could be from the scan, from the 3D modelling, from the way the tissues move during donning, or something else we didn't anticipate. In any case, you should take some videos, photos and measurements to illustrate the issue, and file a warranty claim. Our staff will contact you rapidly to discuss options to resolve the issue.