Socket Geometry and Clinical Outcomes of Manual vs Digital Sockets for Lower-limb Amputees

The most important aspect of a lower-limb prosthesis is the socket as the interface between the human and the mechanical prosthetic system. Proper fit of the socket to the residual limb is a critical factor in determining comfort, suspension, energy expenditure and ultimately the functional efficiency of the remaining prosthesis. Patients may not wear their prosthesis if they find the socket uncomfortable. Traditional manufacturing of prosthetic sockets is a high-skill process involving several stages. Capturing the shape of the residual limb and modifying the mould is performed with a manual, hands-on approach. This leads to inconsistencies between clinicians, and increases the likelihood of human error. There is opportunity to improve this process with advanced computer-aided design (CAD) and manufacturing (CAM). 3D printing can be leveraged for its ability to effortlessly manufacture one-off, complex and organic shapes, such as prosthetic sockets. However, the digital method removes the tactile feedback that the clinician generally benefits from when manually designing the socket, thus leading to some uncertainty in how they are modifying the socket. Moreover, the difference in the learning curve may cause inconsistencies in modifications made by different clinicians. While clinicians may be hesitant in their knowledge-transfer from a manual to digital method, sockets designed using CAD still produce successful outcomes. To facilitate wider-spread adoption of 3D printing as a standard tool in the clinic, more research is needed to better understand how the digital design process affects the geometry of the socket, and how this affects clinical outcomes for amputees. The investigators hypothesize that (1) digitally-designed sockets and manually-designed sockets will have geometric differences, (2) the digitally-designed socket will result in better clinical outcomes compared to manually-designed sockets, and (3) improved clinical outcomes will correlate to geometric differences centred on particular regions of the socket. However, a feasibility study is needed to inform an effective protocol. This feasibility study aims to explore socket geometries and prosthetic outcomes compared between manually-designed and digitally-designed devices for lower-limb amputees. Findings will help in improving the current 3D printing techniques and exploring outcomes for the users.