Amputation is performed when arterial reconstructive surgery has failed or is not technically possible.
- Congenital–Deformities in infants (1% of all cases).
Peripheral vascular disease (arterial disease, usually arteriosclerosis of the lower aorta and its branches)–majority of patients are elderly (64%).
- Trauma–majority of patients have been in road traffic accidents and are young adults (8%).
- Malignancy (4%).
- Metabolic–diabetes giving rise to ulcers and gangrene(21%).
- Infection–bone disease (2%)
- (Department of Health statistics, 1985) .
Amputations due to malignancy are decreasing whilst those due to peripheral vascular disease are increasing.
- Transmetatarsal–Difficulty in healing but no prosthesis required–only an adapted shoe.
- Symes (through ankle)–Rarely used for vascular patients but suitable for trauma and infection. Again, can walk without prosthesis.
- Below knee (BK)–Ideal amputation site. Stump length 12.5–15 cm from knee joint. If the stump is too long, no muscle bulk is left for myoplastic flap. This level retains the knee joint, giving more mobility with lower energy requirements. The main problem is poor healing, particularly in vascular disease.
- Through–knee disarticulation–No bone section is involved and the stump is strong with no muscle imbalance but the knee is cosmetically poor and prosthetically difficult. It is unsuitable in the presence of arthritis at the knee and a hip flexion deformity.
- Gritti–Stokes (femoral condyles)– Good healing qualities but unsightly prosthesis.
- Mid–thigh (above knee, AK)–Very good healing qualities but mobility is reduced due to loss of knee joint and higher energy requirements for function. The prosthetic knee mechanism must have 12 cm clearance, therefore, the soft tissues of the stump should be at least 12 cm above the knee joint.
- Hip disarticulation–This is used in trauma or malignancy, not for peripheral vascular disease. The hip joint is disarticulated and the pelvis is intact.
- Hemipelvectomy (hindquarter)–Removing the lower limb and half the pelvis with a muscle flap covering the internal organs. This level is used mainly in malignancy.