The current method used to measure a stump to fit a prosthesis involves making a plaster cast. An impression of the stump is made in plaster, which is then used to model a socket for fitting the prosthesis to the patient’s limb. This procedure has several disadvantages.

• It can be distressing for the client.
• It is a time-consuming and therefore relatively expensive process.
• The final shape of the socket cannot be modelled until an instrument maker has corrected the impression. This requires highly individual, specialized knowledge, which cannot be translated into protocol.
• It is important to store the socket model for a period in case it is needed for a replacement prosthesis. A lot of storage space is needed and the plaster casts themselves are easily damaged. This method of ‘data storage’ is therefore a highly unreliable and costly business. The current method is difficult to replicate and therefore unnecessarily expensive.

There are plenty of CAD/CAM techniques available to the industry. However, they are usually developed for larger-scale markets. In industrial terms, the orthopaedic market is relatively small (e.g. only 4,000 prostheses are fitted per year in the Netherlands). In addition, specific aspects need to be considered when applying these techniques in the prosthetics industry, such as the fact that a socket manufactured on the basis of a scanned stump may need to be altered to accommodate the soft tissue in the stump.

The aim of the project

The aim of the project is to devise a practical CAD/CAM technique, based on existing technology, which can be used to measure clients for a prosthesis without the need for a plaster cast. The technique must be economically feasible, less distressing for the client than the current method, less time-consuming, less expensive in terms of the measuring process, easier to replicate and less dependent on individual know-how.