Amputation of The Leg

The amputation of a leg is a major happening for a person and represents an upheaval in their life, with psychological problems added to the difficulties of learning the rehabilitation, the management of the new prosthesis, and the relearning of ambulation. The surgeon's plan will be to manage the process to allow the patient early access to rehabilitation, reduce their energy requirements in walking to the minimum and allow them to manage the prosthesis successfully. Many new skills have to be learnt such as mobilising without the new limb, checking the skin pressure areas and managing to get the limb on and off.

A skilled and experienced team is required to teach the patient all the knowledge and skills they need for maximum independence and this includes the surgeon and his team, the medical advisers, the prosthetist, an occupational therapist, the physiotherapist and employment and social facilitators. Lower limb amputations are increasing as the populations of industrialised countries continue to age and with that the main reason for amputation, peripheral vascular disease. The ratio of below knee amputations to above knee amputations has changed as surgical skills for keeping the knee joint have increased, leading to the present occurrence of 70% below knee.

Weight transfer can be achieved indirectly by allowing pressure through a bony point higher up the leg and also by effecting force transfer through the sides of the leg tissues. There may often be a pain issue after this procedure despite modern prosthetic accomplishments and if the pain is significant it can lead to limited use of the prosthesis, functional reduction and eventually to further attempts at surgery.

Other reasons for amputation are less common and include tumours, infections and congenital abnormalities of the lower limbs. Overall amputation is considered an operation which involves reconstruction rather than just removal of a limb, as the patient's future life and independence is the crucial matter. The higher that the surgeon has to amputate the limb the higher levels of energy are needed for walking, with the speed of walking decreasing and the required oxygen consumption increasing. Low below knee amputation may make little difference to the energy required for gait, however once the level moves up to mid thigh the load may be over 50% more.

The amount of energy needed for normal ambulation is vital as patients who have had an amputation typically have vascular disease and other medical problems which require them to use most of their limited available energy in walking. If so much energy is consumed by simply walking then functional independence may be unrealistic. Healing of the tissues and the skin after amputation may be difficult or slow due to the likely ischaemic nature of the limb's tissues, making important limits to the eventual independence of the patient. The interface between the prosthesis and the leg is now performed by the soft tissues at the site.

The amputation stump region must be large enough and the tissues be of good enough quality to allow effective gait by transmitting the lengthways and shearing forces which will be transmitted through it from the socket of the new leg. Direct weight bearing on the end of the stump can occur in amputations which are performed through a joint such as the knee and the ankle, but this style of amputation has its difficulties. The new knee joint is inevitably formed below the level of the old one, causing the knee to stick out obviously further than a normal knee and the calf to be correspondingly shorter.

More indirect weight transfer can be accomplished by allowing a higher bony area to take some of the force with other forces being transferred across the sides of the soft tissues of the leg. Pain may still be an issue for many patients despite the great advances made in prosthetic technology. If the pain is severe enough it can lead to further surgery, reduced function and limited wearing of the artificial limb.