Definition & Overview
An above the knee amputation is a surgical procedure that becomes necessary when irreversible damage or disease affects the area above the knee joint or when complications arise after a lower limb amputation. Also known as trans-femoral amputation, the goals of the procedure are to remove the diseased or damaged tissue and any crushed bone, smoothen uneven bone, seal off nerves and blood vessels, and prepare the stump so that it can accommodate a prosthetic limb.
Who Should Undergo and Expected Results
An above the knee amputation is recommended for patients whose leg is severely damaged or diseased until a point above the knee and if no other treatment, surgical or otherwise, can treat the condition. In these cases, amputation is performed to prevent infection and other serious complications that can further threaten the patient’s health and life.
The most common causes of severe damage and disease to the legs that require above the knee amputation are:
- Diabetes complications
- Vascular problems causing poor blood flow in the lower limbs that can no longer be treated using other methods
- Severe infection
- Traumatic injury
- Tumours or cancer
- Congenital disorders or deformed limbs
- Neuroma or the thickening of nerve tissue
An amputation is used as the last resort if all other treatment options have failed to address the problem at hand.
A successful knee amputation is followed by physical therapy, which goal is to help amputees relearn how to perform their daily activities after losing a limb. Physical therapy sessions are designed to strengthen the hip and improve range of motion and balance. Most amputees undergo regular physical therapy sessions for an entire year. They can also undergo training on how to move around using prosthetic device should they decide to use one. Prosthetic devices are designed and fabricated based on the needs, movement goals, and life circumstances of the patient.
Patients are also advised to undergo counselling sessions to help them cope with the psychological and emotional effects of losing a limb as well as pain management therapy to help them deal with the pain that normally follows such a procedure. Modern pain management techniques that can be used include transcutaneous electrical nerve stimulation, joint manipulation, massage, and desensitisation.
How is the Procedure Performed?
Above the knee amputation is an in-patient procedure performed by either an orthopaedic or vascular surgeon under general, spinal, or local anaesthesia.
Once the effects of anaesthetic have taken effect, the surgeon makes an incision above the knee, divides the muscles, and clamps the blood vessels to gain access to the bones, which are sawed through to make a clean cut. Once the limb is fully cut, the surgeon sews the muscles together, shaping them around the end of the remaining bone to form a stump. The skin is then sutured closed over the muscles. The entire procedure may take several hours, depending on the circumstances surrounding each case. If the patient has diabetes, greater care has to be taken to prevent complications.
After the procedure, the stump is dressed in bandages to protect it as it heals and drains are placed to avoid fluid accumulation in the treated area. The whole stump is then covered with compression stockings or a cast. Patients are given pain relievers, antibiotics, and anticoagulant medications to help prevent common complications associated with most surgeries.
After the procedure, patients are required to stay in the hospital for close monitoring between 5 and 14 days, depending on their general state of health. Should complications arise, they will have to stay longer.
Possible Risks and Complications
Methods and techniques used for above the knee amputations have improved immensely over the years. However, although rare, complications can still occur. These include:
- Poor healing of the stump
- Swelling that does not subside or improve after four weeks
- Phantom limb sensation/pain
- Blood clot
- Skin breakdown
- Contractures, or when the remaining soft tissue in the residual limb tightens and restricts joint motion due to lack of movement
In addition, patients are also at risk of suffering from adverse reactions due to the use of general or spinal anaesthesia.
The patients’ risk of experiencing post-amputation complications may be influenced by certain lifestyle factors, such as smoking and drinking, as well as by any underlying medical conditions. If complications occur, there is a possibility that the patient may need re-amputation. Studies show that smokers are 25 times more likely to require re-amputation due to complications than non-smokers.
Sullivan J., Uden M., Robinson KP., Sooriakumaran S. “Rehabilitation of the trans-femoral amputee with an osseointegrated prosthesis.” Prosthetics and Orthotics International. https://poi.sagepub.com/content/27/2/114.abstract
Gagnon C., Grise M., Potvin D. “Predisposing factors related to prosthetic use by people with a transtibial and transfemoral amputation.” American Academy of Orthotists and Prosthetists. https://www.oandp.org/jpo/library/1998_04_099.asp