Leg amputation is one of the many complications of type 2 diabetes mellitus. According to the Centers for Disease Control and Prevention, there were approximately 71,000 leg amputations due to diabetes mellitus in 2005. Most people were older than 75 years old, and most of their amputations were toe and above-the-knee amputations. For those younger than 75 years old, the majority of amputations were toe and below-the-knee amputations.
Development of Amputations
In America, diabetes mellitus is the most common cause of leg amputations not caused by trauma, writes Alvin Powers, M.D., director of the Vanderbilt Diabetes Research and Training Center, in "Harrison's Principles of Internal Medicine." The nerves in the foot normally alert someone that there is an injury in that foot. People with diabetes have problems with their nerves and many times do not know that their foot has been injured. Due to problems with the circulation in their legs and feet, their wounds do not heal well. Even minor wounds can become larger and get infected. If the infection gets worse and does not heal, this can lead to amputation.
AKA and BKA
AKA is the abbreviation for above-the-knee amputation. Surgeons now use the term transfemoral amputation instead of AKA because it is an international term, says Douglas Smith, M.D., of Harborview Medical Center, in "Current Diagnosis & Treatment in Orthopedics." "Trans" is from the Latin for going through or across, and femur is the name of the thigh bone. BKA stands for below-the-knee amputation. Transtibial amputation is the preferred term for BKA, as the tibia is the larger bone below the knee. For people with diabetes, both types of amputation are due to infections that progress to ulcers and then gangrene and osteomyelitis. Gangrene is tissue that dies because it did not have enough blood and oxygen. Osteomyelitis is an infection of the bone.
Evaluation for Amputation
Dr. Smith explains that physicians perform several studies to decide if amputation is the best choice. A Doppler ultrasound checks on the level of blood circulating through the leg. Another test measures the amount of oxygen in the tissues of the leg. A Xenon study can predict how well the remaining part of the leg will heal after an amputation is done, but it is so expensive that it is rarely used. The skin fluorescence study checks on the amount of blood flow in the skin. Lab tests check on the level of albumin and lymphocytes. Albumin is a type of protein, while lymphocytes are a white blood cell that fights infection. People who have problems with their circulation but need an amputation will heal better if they have a certain amount of albumin in their bloodstream and a certain number of lymphocytes.
References
- Centers for Disease Control and Prevention: Hospital Discharge Rates for Non-traumatic Lower Extremity Amputation
- Centers for Disease Control and Prevention: Number (in Thousands) of Hospital Discharges
- "Current Diagnosis & Treatment in Orthopedics"; Harry Skinner, M.D., Ph.D.; 2006
- "Harrison's Principles of Internal Medicine"; Anthony Fauci, M.D., Dennis Kasper, M.D., Dan Longo, M.D. et al.; 2008
