Advantages And Disadvantages Of Transfemoral Amputation

\section{Introduction}

\subsection{Motivation}

Amputation, is surgically removing all or a part of the limb or arm, leg, foot, hand, toe or finger. The amputation that occurs through the femur is a transfemoral or above knee amputation. Transfemoral amputees form the second largest group of amputees in the world \cite{oandp}. Hence, transfemoral prosthesis is an important field of study. Transfemoral amputation is mostly found in oncology patients. For vascular disease, severe disease affecting the circulation in the lower limb, a transfemoral amputation is performed. Other common reasons for the amputations are severe injury, like from a vehicle accident, serious burn, cancerous tumor in the bone or muscle of the limb, thickening of nerve

However, each of these methods come with some advantages and some disadvantages that are discussed in this paragraph. X-ray, one of the commonly used method can be used only in a static manner to analyze residual femoral movement within transfemoral sockets and also residual tibial movement within transtibial sockets. The contact between the residual limb and prosthetic socket can also be studied using X-ray imaging. However, X-ray images cannot be used for volumetric and three dimensional\thinspace(3D) measurements. Using CT, the 3D shape of the residual limb can be reconstructed from a number of two dimensional\thinspace(2D) slices that are taken transversely to the limb's long axis. The major advantage is that the CT data can be incorporated into a computer aided design\thinspace(CAD) prosthetic design system and the 3D volumetric images obtained can be used to develop a finite element model for the residual limb. These finite element models can then used to study for interface analysis of bone and soft tissue. However, CT is expensive and also dangerous for repeated measurements as it uses a lot of of ionizing

A set of carefully chosen experiments such as accuracy test, repeatability test and resolution test are performed to calibrate the ultrasound transducer. Meanwhile, efficient methods to analyze the real time signals are developed. After the calibration of the transducer, they are used to find the position of the femur in a normal, healthy human test subject. The values so obtained are validated from the values obtained from MRI.

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The structure of the thesis is as follows. In chapter 2, the basics of ultrasound and anatomy are discussed. Also the current research in the field of the use of ultrasound to monitor the position of the residual femur in the transfemoral socket are discussed. In chapter 3, an elaboration of the calibration experiments with the procedure and calculations is provided. In chapter 4, the results of the calibration experiments are discussed. Finally, the thesis is concluded with the discussion of the calibration of the ultrasound transducer to monitor the position of the femur