This patient received a left below-knee amputation. The length of the patient’s leg
below his knee ranges from 5 to 7 inches. This allows for fitting into an ideal
prosthetic leg once surgical wounds have healed.
Q: What are the goals of an amputation below the knee?
Answer: The goal of amputation is to remove unhealthy tissue and create a remaining leg that is less painful and more useful. Amputation can improve
quality of life for many patients. A below-knee amputation (BKA) is an amputation often performed for
foot and ankle problems. The BKA often leads to the use of an
artificial leg that can allow a patient to walk. A BKA is performed
roughly in the area between the ankle and knee. This amputation
provides good results for a wide range of patients with many different
diseases and injuries.
Q: What signs indicate amputation may be an option?
Answer: A BKA is performed when a patient is severely injured or has a severe infection. Other reasons for amputation can include non-healing
ulcers, chronic pain, birth defects and tumor. The decision to amputate involves many factors and is done after a thorough discussion between patient and orthopaedic surgeon.
Q: When should I avoid an amputation?
Answer : There are many medical reasons why a patient may not be a good candidate for a BKA. Below is a list of some of the more common reasons.Poor blood flow: Patients with poor blood flow should not undergo an operation without proper evaluation before surgery. Adequate blood
flow is necessary for wound healing. This may mean a referral to a vascular specialist before surgery is considered. Medical problems: Severe heart or lung disease, a poor immune system or bleeding problems may be reasons to not have surgery.
Infections or tumors that extend above the knee: In cases where an infection or tumor goes above the knee joint, a higher level of amputation may be required.
Scar tissue or skin and muscle loss: Patients with scarring, tissue grafting or tissue loss may not be candidates for a BKA. Such patients may not have adequate skin or muscle to heal a wound or to use an artificial leg.
Limited knee function or knee pain: Patients who cannot straighten their knee or have pain and giving way at the knee may find it difficult to use an artificial leg.
Patients who already do not walk or stand due to other reasons may not benefit from a BKA.
General Details of Procedure
If amputation is being considered, a team approach should be used. This often means meeting with numerous specialists. This may include your orthopedic surgeon; your medical doctor, who can make sure you are healthy for surgery; a prosthetist, someone who specializes in making artificial limbs; a physical therapist; and a rehab doctor. Support groups and patients with similar problems who have undergone
amputation can be excellent resources before and after surgery. During surgery, the leg is amputated at a level that removes as much damaged tissue as possible. There is no single length of amputation that
will work for all patients. In general, several inches of leg bone below the knee is required in order for an artificial leg to be properly fit. There is not an advantage to a very long residual leg as it does not improve the ability to fit and wear an artificial leg.
There are many different techniques for performing a BKA. Each surgery is customized for the individual patient. Most patients are completely asleep for the procedure. On occasion, a spinal anesthetic or a nerve block with a sedative may be appropriate.
An incision is made below the desired level of the amputation. The calf muscles and skin are cut in a way that creates a “flap.” The leg bones are both cuts with a saw. The calf muscle is then folded up over the ends of the bones and is held with sutures. The skin is closed with sutures
or staples. Some surgeons may place a temporary drain to help prevent blood from pooling under the flap. A compressive dressing is applied to minimize swelling. Sometimes a cast is applied for added protection. The surgery usually lasts two to three hours. Patients spend some time in
a recovery area and are then transferred to a hospital floor.
Q: What happens after surgery?
Answer: Most patients will be admitted to the hospital for at least one night following the procedure. Many are able to return home as long as they have help at home and are able to walk with crutches or a walker. Some patients who need more assistance with walking or have multiple medical
problems may benefit from a stay in a rehabilitation facility until they are ready to return home. The incision will heal over a period of two to six weeks. This can depend on patient factors such as blood flow, quality of skin and soft tissue,
and medical conditions such as diabetes. Swelling (edema) is common and may last for months if not years. Swelling is often treated with a compression stocking or “shrinker.” Decreased swelling is critical for proper use of an artificial leg. If a limb is
swollen when the prosthesis is fitted, it will be loose when the swelling improves. Similarly, a swollen limb won’t fit into an artificial leg. Complete healing may take up to a year. The artificial leg is continually adjusted during that time to make sure of a proper fit.
Most surgeons will want the incision to be completely healed before allowing a patient to walk with an artificial leg. Most patients are fitted with a temporary artificial leg within the first three months.