**2.1 Components**

*Prosthesis*

combined with subjective verbal feedback from patients to minimize suspensiondependent movement between the socket and residual limb. This subjective information is used to revise socket parameters such as volume, geometry, and type of suspension to provide a "best" fit for the amputee. In day-to-day living, the volume of mature residual limb (>18 months postamputation [3]) are subject to short-term [4] and long-term [5, 6] changes in volume that compromise socket fit and performance. More than 80% of amputations in the U.S. are the result of complications from vascular disease and diabetes [7, 8]. Less than 10% of lower-limb amputation results from trauma [9]. In the US, among those that live with a lower-limb amputation, a growing number of which are Service men and women [10–12], the limb volume changes adversely affect fit, performance, and residual limb health [6]—including skin breakdown and ulceration [13] (**Figure 1**) that can require surgical revision of the amputation. The requirement for surgical revision is known to be as high as 30% [14]. This review primarily focuses on skin health in the residual lower limb and the need for objective monitoring and evaluation of changes at the interface of the biological entity (limb skin) and the artificial entity (prosthetic limb) for sustained

optimal limb health. Similar issues could apply to the residual upper limb.

*(A) Prosthetists use a scanning device to digitize limb shape. (B) Digital model is modified to create a positive mold for socket fabrication tailored to the residual limb. (C) Tissue injury as a result of using a pin-locking suspension system. (D) Injury healed once the amputee was fit and began wearing an elevated vacuum* 

**46**

**Figure 1.**

*suspension socket (EVS).*

There are two main types of prosthetics that replace a partial or complete loss of the lower limb and these include: (a) below the knee or transtibial (TT), where a prosthetic lower leg is attached to an intact residual upper limb, (b) above the knee or transfemoral (TF), where a prosthesis replaces the upper and lower leg and knee. Each of these types of prostheses is composed of key parts: the prosthetic limb, a socket (interface between the biological component (e.g., patients' body) and the artificial limb), the attachments and the control system.
