The invention of the CAD/CAM system revolutionized the manufacturing and distribution of prostheses and orthotics on a global scale.
FREMONT, CA: For ages, prosthetic socket manufacturing has been a meticulous and painstaking art to create a pleasant, supportive, and functioning socket for the remaining limb. The body's weight is transferred through this socket to the remainder of the prosthetic device and the ground. It is the most critical component of a prosthetic device and the most customized and unique component of the prosthesis. As one might anticipate, there are currently many approaches, styles, and philosophies for creating the optimal socket.
A socket that is an identical replica of the residual limb is not good. The socket must be precisely indented in locations that can withstand force transmission and alleviated away from the residual limb in areas that are less tolerant of stress and pressure. These modified parts of the socket are referred to as regions.
CAD/CAM, or Computer-Aided Design/Computer-Aided Manufacturing, is used in prosthetics and orthotics. Automated technology begins with acquiring an accurate and reproducible digital image of the amputated limb and its transfer to a computer. Researchers continue to argue the optimal method for "digitizing" the residual limb, whether or not the limb should be molded with a cast, and whether or not the anatomic data should be collected while weight-bearing. Additionally, the degree of precision of the supplied data continues to be a point of contention. The first successful devices incorporated a hand-wrapped cast, which required some traditional shaping and tweaking by the prosthetist during the casting process. This results in some differences in the "digital" beginning map. If the same patient is cast ten times, each cast, and thus each digital map, will be slightly different.
After obtaining a digital representation of the remaining limb, the software is utilized to make the necessary alterations to turn it from an accurate mold of the amputated limb to the shape of a functioning prosthetic socket. This is referred to as rectification, and it involves the introduction of indentations in areas that can handle higher weight and relief in those that cannot. Most software solutions include templates that identify these locations and apply these alterations uniformly across all limb sizes and shapes. There are dozens of variants and hypotheses regarding the precise placement and shape of these regions, how to define the subtle nuances of progressive versus abrupt modification, and the location of the apex and amount of the change. Most software solutions enable an individual prosthetist to fine-tune the correction process. Prosthetists can build their templates, allowing them to replicate their most popular or effective "rectifications" for other patients.
After rectification, a modified model is carved, and a socket is built over it. The socket must then be aligned to position the residual limb optimally regarding the remainder of the prosthetic device, the force lines of weight-bearing, and the ground. Again, there are numerous mechanisms and materials for fabricating the socket. While many prosthetists continue to fabricate each socket in-house, fabrication does not have to be done at the prosthetics clinic, and central construction sites are available to assist with various stages of the rectification and fabrication process. Once the socket is supplied, minor changes, such as grinding or cushioning of small places, are frequently required.
The 1985 Prosthetics and Orthotics International Special Issue on CAD/CAM records highlight many of this era's initial thoughts and ideas. George Murdoch described how this technology would let practitioners and patients examine alternate socket design theories or fresh concepts.
Bo Klasson, writing in 1985, gave a great overview of CAD/CAM, highlighting several of its uses and benefits. Automated systems can reduce duplication of work, ease three-dimensional learning geometry, simplify data input and presentation, simplify product documentation, and store experience and information from past designs.