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.

The team managing the amputee needs to be multidisciplinary and skilled in this field to get the best out of the patient in terms of independence and the team may consist of the physiotherapist, an occupational therapist, the surgeon, the personal medical practitioner, a prosthetist and advisors on social care and employment. As the industrialised countries’ populations continue to age the number of amputations will also rise as the main cause of amputation is vascular disease in the periphery. The number of above knee versus below knee amputations has changed as surgeons have learned to preserve the knee joint in more cases, with seventy percent now being 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.

Amputation is also employed for less common conditions such as infections, congenital lower leg abnormalities and tumours. The planning for an amputation should be viewed as an operation targeted at reconstruction and not just removing a body part, aiming for the planned independence and function of the patient. As the level of the amputation progresses up the leg this increases the work of walking, requiring increased levels of oxygen concentration, increased expenditure of energy levels and reducing the speed the person is able to walk. Below knee amputation shows little increase in energy needed for walking but mid thigh can increase this by fifty percent.

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.

Effective walking requires the soft tissues of the stump of the limb to be big enough and of high enough quality to manage the shearing and lengthways forces applied to it by its close apposition to the prosthesis socket. The end of the leg can bear the stresses directly in a lengthways direction in those amputations through the joints such as the ankle and the knee, though this type of amputation can present problems. The prosthetic knee joint has to be formed below the level of the original and this forces the knee to project further than a normal knee and so makes the calf significantly shorter.

Jonathan Blood Smyth is the Superintendent of Physiotherapy at an NHS hospital in the South-West of the UK. He writes articles about back pain, neck pain, and injury management. If you are looking for physiotherapist in Blackpool visit his website.