Selection of level for lower limb amputation

Abstract

Selection of level of lower limb amputation following trauma or in dysvascular patients must be based on experience, and a broad knowledge of the early and late problems following amputation and prosthetic fitting. Successful wound healing is important to achieve, so that the patient can be soon fitted with a prosthesis, and become involved in a rehabilitation program with the emphasis on early return to work and/or the home environment. It is helpful if the surgeon concerned has some knowledge of the advantages and limitations of prosthetic use at the various levels in the lower limb - too much information in the past has been relayed by word of mouth or repeated ad nauseam in orthopaedic textbooks. After trauma, it is usually a young male patient who must cope with limited function, loss of body image, difficult relationships with friends and loved ones leading to changes in their pattern of life and future plans. The dysvascular patient, however, is running ‘out of time’. Stewart 21 reported a mean survival in peripheral vascular disease patients of only four years plus two months, when compared to the diabetic dysvascular patients of only three years plus eight months, after the amputation. If a patient survives for more than three years, there is a high chance that the other limb will be lost during that period. Young diabetic patients without peripheral vascular disease present with significant problems from peripheral neuropathy, osteoarthropathy of the foot and ankle, retinal damage and kidney problems often requiring long-term dialysis. These patients have limited life expectancy and selection of the level of amputation must take into consideration the necessity for early prosthetic fitting and rehabilitation. Diabetic patients with absent foot pulses should not be treated any differently from non-diabetics when the level of amputation is being considered. Similarly, elderly patients with athero sclerosis should be assumed to be diabetic, and this assumption should be verified by appropriate biochemical tests. Both groups should be intensively investigated in the hope that angioplasty or by-pass procedures may prolong limb survival if only for a limited period. There have been suggestions that the level of amputation and need for revision in dysvascular patients may be affected adversely by prior attempts at revascularization, but other studies fail to support this claim. 22,23 Unfortunately, one must be both realistic and pessimistic about prosthetic fitting and use, especially in trans-femoral amputees. In a recent publication, 24 the authors conclude that only 10% to 15% of dysvascular amputees achieved mobility around the home on their prosthesis, and only 5% rehabilitate well independent of their wheelchair. They emphasize that when amputation is inevitable, more consideration should be given to surgery that optimizes wheelchair rehabilitation. These findings must make a surgeon responsible for performing the amputation continually aware of the importance of preserving the knee joint in the elderly dysvascular patient.