Lower Limb Amputation – Part Two

Patients for amputation do not usually present diagnostic difficulties as they are mostly referred with a history of peripheral vascular disease and extensive treatment. The gradual blocking off of the minor blood vessels causes gangrene in the toes and ulcers on the areas which suffer pressure. This is followed by invasion by bacteria which leads to soft tissue infection and then to infection of the bone. Treatment can be long and drawn out with repeated operations and attempts at lesser amputations, leading to a long period where the patient is non-functioning and in pain.

In accidents and injuries the amputation may be traumatic or involve a compound fracture severe enough to damage the nerves and blood vessels beyond salvaging. Here an amputation may be the best choice as against long term efforts at salvaging the damaged limb. An attempt at salvaging the limb may result in a non-functioning leg which is painful, leading to mood changes such as depression and limited activity. A careful assessment of the potential to save the limb needs to be made after the injury to avoid a lengthy and painful treatment period when amputation might deliver good function much sooner.

With amputation the major goal is to preserve the length of the leg and to get the maximum functional use from the limb. As the operation cannot be reversed the surgeon must be sure the decision is correct and the only limits are the medical fitness of the patient to manage operation. Because the patient’s poor medical status will likely be closely linked to their abnormal limb the operation should remove the negative influence on their health and may save their life. Preparation for the operation, rehabilitation and life after amputation is a multidisciplinary matter also involving physiotherapists, social workers and psychologists.

The management of severe trauma to the leg has dramatically improved with the ability to fix fractures internally, perform microsurgery to the blood vessels and attempting to restore the blood supply to areas where it is compromised. If these techniques do not work then amputation may be seen as a failure of treatment but should be seen as a reconstruction procedure leading to increased functional ability. Advances in amputation techniques have seen much less development and patients still present problems with feeling unstable, persistent pain, oedema and limited wear of the prosthesis.

The plan for the surgery is to cut any nerves under a tensioned state and to place the cut away from the bone ends, stitching opposing muscle groups together and underneath the bone ends and to maintain the length of the skin to allow it to fold under the cut end. This way the end of the new extremity can have good skin cover and a suitable cushion of muscle to absorb forces. A typical surgical rule is for every 30 centimetres of a person’s height to give 2.5cm of length in the new limb. A wound dressing is then applied and the person given their post-operative painkillers.

After the immediate period post-operatively the patient will be assessed and treated by a physiotherapist who will review their respiratory condition, teach correct positioning of the remaining limb, encourage appropriate exercises, practice transfers and progress to walking with an aid if possible. Around the two week point the physiotherapist may progress to exercise for the affected extremity and start with a desensitisation programme for the operated part. This involves reducing the tenderness of the limb end so that it can cope with the pressures and stresses of wearing a prosthesis and weight bearing.

The wound and area may have settled by the six week point to allow the beginning of the development period for wearing the prosthesis, however some patients will not cope with using one due to poor understanding, muscular weakness and reduced balance capacity. There is a large number of complications which may get in the way of restoring the maximum degree of physical independence for the patient. As the local circulation is poor the wound may breakdown or the skin give problems, there may be local swelling, losses of joint movements, phantom sensations and pain problems.

Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapy, back pain, orthopaedic conditions, neck pain, injury management and physiotherapists in Edinburgh. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.

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Filed under back pain by Jonathan Blood Smyth on Dec 20th, 2009.

Lower Limb Amputation – Part Two

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