Pliance-RLS prosthesis: Pressure between human and prosthesis.


Pliance-RLS prothesis: Pressure between human and prosthesis |

The problem with the adaptation of prosthetic sockets is that they are not optimally adjusted; for example, in a thigh or leg prosthesis, it is important to have optimal force transfer between the prosthetic socket and the amputation stump (the residual limb) because the bony structure is no longer present after amputation, which means that forces must be transferred through soft tissues to the prosthetic socket. The problem with this is that the muscles change shape when contracting and the socket remains static. A compromise must be made between the fit of the static socket and the dynamic changes of the amputation stump due to muscle contraction. Sockets are usually held in place by suction on the amputation stump, which means that a certain minimal pressure between the amputation stump and socket surface is necessary, but at the same time the pressure must not be too high in order to maintain comfort and prevent injuries.  

pliance sensors can help in the analysis of the optimal pressure between the socket and amputation stump through pressure distribution measurement to ensure appropiate pressure. 

Pliance measurements can ensure to maintain comfort and prevent injuries while still ensuring proper fit and function of the prosthetic socket. 

The pliance-RLS prosthesis system has been developed for socket evaluation and fit. It provides a quantification of the level of pressure at the residual limb/socket interface during static and dynamic movements.

As a result of their design and material selection, the pliance-RLS sensors are flexible and elastic and have the ability to conform very well around highly contoured sites. This is particularly advantageous in prosthetics because of the highly irregular surface and geometry of the residual limb and the shape of the socket.

The pliance-RLS sensors include a dense array of sensors, with a small individual sensor area. This allows recording of interface pressure at a discrete location of the socket. The length of the sensor pad is appropriate for use on a short or long transtibial socket.The different standard shapes allow testing of different
anatomical areas simultaneously. Custom made sensors are also available.

Introduction: Due to poor socket fit and improper pressure distribution, it is common for amputees to develop residual limb problems such as discomfort, pain, skin irritation, pressure ulceration and associated infection. Up to now the most frequently used method of inspection for these problems is individual inspection and verbal feedback. Measuring pressure at the interface between an amputees` residual limb and prosthetic socket could provide valuable information in the process of prosthetic socket fabrication, modification and optimal fit. For that application novel offers the pliance® prosthesis measuring system PMS.

The pliance®-PMS software package operates with Windows XP and Windows 7. It is user friendly and contains many useful options for fast pressure data collection, analysis and data presentation.


Features of pliance® PMS:

  • conforms perfectly to anatomical areas
  • monitors simultaneously different anatomical areas of the limb
  • measures highly accurate calibrated values
  • scans uo to 20 000 sensors per second
  • allows configuration and localisation of sensor matrix via expert software in 2D- and 3D mode „ stores data on SD-card
  • sends data online via built-in Bluetooth® telemetry to any PC
  • can be synchronised with video and EMG
prosthesis pressure measurement - sensing force
prosthesis force and pressure measurement sensors

With the aid of the trublu® calibration device, all sensors are individually and simultaneously calibrated with homogeneous air pressure. Calibration guarantees accurate and reproducible data collection. Calibration systems are available in various sizes.