How Do Above-the-Knee Prosthetics Work

Individuals facing amputation above the knee can discover a renewed sense of mobility and independence through above-the-knee prosthetics. These prosthetic legs are meticulously designed to replicate the function, and often the appearance, of a real leg. While the benefits of above-the-knee prosthetics can greatly enhance the quality of life, it's important to recognize and address potential problems associated with this type of prosthetic solution. With years of experience in the field, our team at PrimeCare Orthotics & Prosthetics is uniquely qualified and ready to help answer your questions about this topic.

What Is Above-Knee Amputation (AKA)?

Above-knee amputation is a surgical procedure that involves the removal of the leg above the knee joint. This type of knee amputation is typically the result of critical health issues such as peripheral vascular disease, which restricts blood flow, leading to the death of tissues. Other causes may include unmanageable foot or leg ulcers, particularly in diabetic patients, or severe trauma resulting from accidents. We understand that the decision to proceed with an above-knee amputation is never taken lightly and is usually a last resort when other medical interventions have failed to resolve the underlying problems.

Preparing for an Above-the-Knee Amputation

Preparing for a lower extremity amputation requires thoughtful consideration and careful planning. In most cases, you'll work closely with a specialized vascular or orthopedic surgeon who will guide you through the process. Here are some steps you may need to take:

• Consultation: Have a detailed conversation with your surgeon about the procedure, risks, and outcomes including rehabilitation and prosthetic training.
• Preoperative Instructions: Once surgery is scheduled, your provider may instruct you not to eat or drink after midnight before surgery. They'll also guide you on which medicines to take or avoid.
• Antibiotics: You may be given an antibiotic through your IV to prevent infection. Be sure to inform your healthcare provider about any allergies to antibiotics.
• Imaging and Testing: In addition to doctor-prescribed antibiotics, an angiogram might be needed to check blood flow, involving a catheter, contrast liquid, and X-rays. Let your provider know if you have allergies to contrast liquid. Oxygen level tests in your leg might also be conducted to decide the amputation site.
• Physical Therapy: Preoperative physical therapy might be recommended to strengthen muscles.
• Mental Preparation: Consider counseling or support groups to help mentally prepare for the life changes.
• Home Adjustments: Make necessary home modifications to accommodate mobility changes.

After an Above-the-Knee Amputation Surgery

Patients may experience a variety of physical sensations and changes as they adapt to life without the limb. These might include phantom limb pain, where the individual continues to feel the part of the leg that has been amputated. Phantom pain is normal and is often successfully managed with prescription pain medicine.

• Initial post-surgery care includes the placement of drains to remove fluid from around the incision and respiratory exercises to reduce the risk of lung infections. Patients are encouraged to take deep breaths and cough frequently, often using an incentive spirometer for help.
• Physical care for the remaining limb is critical. Be sure to change positions regularly to prevent complications such as pneumonia or skin pressure sores and specific guidelines for the first 24 hours to reduce swelling. You'll also want to do strengthening exercises for the hip muscles and residual limb, paying special attention to limb positioning to prevent hip tightening.
• Wrapping the residual limb with an elastic bandage helps control swelling and forms the limb into a shape suitable for fitting a prosthesis. This wrapping usually starts within days of surgery and continues until healing is well underway.

As the healing process continues, the focus gradually shifts to selecting the appropriate prosthesis for the remaining limb. This involves collaboration between healthcare providers, prosthetic specialists, and the patient, ensuring the prosthesis fits well and enhances mobility. The goal is to integrate the prosthesis seamlessly into daily life, allowing for improved function and independence.

What Are the Different Above-the-Knee Prosthetic Types?

You’re likely wondering “What kind of prosthetic leg do I need for an amputee above the knee?” There are different types of above-the-knee prosthetics to consider, and the PrimeCare Orthotics & Prosthetics team works with the following technologies:

• C-Leg, Genium, X3 knees, Power/Rheo knees
• Propio Foot
• i-Limb
• I-digits Quantum
• Be-Bionic Hand

Your doctor will work with you on choosing the best type of prosthetic for your needs.

What Type of Prosthesis Replaces the Leg Above the Knee?

Those who need above-knee prosthetic legs (also referred to as a transfemoral prosthesis) usually consist of a custom-made socket, a knee, a pylon, a foot, and some way to suspend the prosthesis from the body. It’s common for patients to be fitted for a prosthetic within a few days of surgery.

Immediately following the procedure, you’ll receive an Immediate Post-Operative Prosthesis (IPOP) to help reduce swelling, protect wounds, and speed up the overall healing process. In some cases, you might receive an AK shrinker, a device that helps to shape your limb for the prosthetic and desensitizes the limb to make the prosthetic more comfortable.

Don't rush the process of getting a long-term prosthesis. It’s important to get both the right type of prosthesis and the right fit. During the process, you will:

• Receive a liner that cushions your limb
• Receive a cast made out of your limb
• Try a diagnostic socket to ensure alignment for the final prosthesis
• Receive subsequent diagnostic sockets to achieve the right fit
• Get a final version of the socket to start gait training
• Finally, select the knee and prosthesis that's best for you

How Does an Above-Knee Prosthetic Work?

There are different parts of an above-knee prosthesis — a socket, knee joint, ankle joint, and foot components. As we mentioned above, you’ll first receive a temporary prosthesis while your residual limb heals, shrinks, and changes shape over a few months of healing. Your prosthesis will be modified to fit your residual limb.

Here's additional information on how the parts of a prosthesis work together:

• The prosthetic leg is made from durable yet lightweight materials. The leg may or may not include functional knee and ankle joints depending on where the amputation occurs.
• The socket is made from an exact mold of your residual limb and it’s designed to fit snugly. The socket helps to attach the prosthetic to your body.
• The suspension system, or how the prosthesis stays attached to the limb, may include sleeve suction, distal locking, or vacuum suspension.

During the rehabilitation process, you’ll begin to learn to function first with a wheelchair and walking assistance devices such as crutches or a walker. Before you learn how to walk with an above-knee prosthetic, you’ll work closely with your physical therapist to learn the necessary skills to use your prosthetic limb. Physical therapists will also provide you with information on how to care for it, including skin checks, hygiene, contracture prevention, exercise, and positioning.

Everyday Routine with an Above-Knee Amputation

Once you have your prosthesis, you’ll need to invest time into ongoing therapy and at-home exercises under the guidance of your doctor. Through time and consistent effort, you can learn balance and coordination. Try to be as patient as possible as it’s not uncommon for rehab to last up to 1 year. You’ll also want to check the remaining limb daily for any irritation, skin breaks, or redness.

Just because you have a prosthetic, it doesn’t mean that you can have an enjoyable and fruitful life. At home, make sure to discuss with your doctor what you can do. When you get the okay, you’ll be able to wash the remaining limb with soap and water. It’s also possible that you’ll be able to drive depending on your specifics. Some people can return to work as soon as 4-8 weeks following surgery although it could take longer.

How Do People with Above-Knee Prosthetics Walk?

As above-knee amputations make it harder to bear weight, the risk of falling is higher. First, those with an above-knee prosthetic leg will use a wheelchair until the risk of falling is low. During this time, you’ll use rehabilitation and physical therapy to build strength. You’ll also be fitted with short prosthetic training feet that help to re-learn balance. Gradually, you'll increase the height of the prosthetic leg to build the strength needed for a full-length prosthetic. Over time and with practice, amputees will be able to walk without the assistance of any devices. In fact, one of our success stories at PrimeCare, Ralph, tells us that one of his biggest accomplishments is walking up and down the stairs without pain after being fitted for his prosthetic.

How Far Can You Walk with a Prosthetic Leg?

The distance that you can walk depends on your injury and overall healing process. Some people can only walk a short distance before getting too tired or feeling too much pain while others can get around as they did before surgery.

How to Play Sports with an Above-Knee Limb

Different sports have unique requirements. Popular sports for those who have prosthetic legs include cycling and swimming. These are popular as they are non-weight-bearing sports. Other people with prosthetic legs may be able to walk, run, dance, or even garden or practice yoga. Think outside of the standard sports and consider trying something you haven’t tried before.

Safely Falling with an Above-the-Knee Amputee

Learning how to fall properly can help keep those with a prosthetic safe. Your physical therapist will practice falling with you. If you're falling, make sure to immediately release any assistive devices you’re using and allow the body to be flexible. If possible, absorb the impact with your hands by using slightly bent elbows and immediately roll to the side to minimize impact. Avoid hitting your head by tucking your chin to your chest.

How to Sit with Prosthetics

When sitting, keep your shoulders back with your pelvis beneath you. Your limb should be aimed at the floor and hang close to your other leg.

3 Tips for Above-the-Knee Amputees to Feel Comfortable

1. Start Slowly: Take your time and be patient when you’re learning to walk with your new prosthetic leg. Parallel bars can help keep you secure and build your confidence without the risk of falling.
2. Shift Your Weight: As you take steps, it becomes an unconscious movement for you to shift weight between your legs. Make sure to practice this shift in weight when you’re learning to walk.
3. Build Confidence Through Repetition: Once you’re comfortable using the basic walking mechanics, practice them repeatedly to build your confidence. The more confident you feel, the better you’ll navigate the world with your artificial leg.

Potential Above-the-Knee Amputation Complications

We’ve outlined some common above-the-knee amputation complications.

What Are the Negative Effects of Prosthetics?

It can be physically and mentally challenging to adjust to a prosthetic leg. Here are some common obstacles:

• Excessive sweating may affect how the prosthesis fits, resulting in skin issues
• Changing residual limb shape that often occurs in the first year after amputation
• Residual limb weakness makes it difficult to use the prosthesis for a long period of time
• Phantom limb pain

Does Leg Amputation Shorten Life Expectancy?

There are prolonged physical and psychological stressors that can impact the life expectancy of lower limb amputees. For example, there's an increased morbidity and mortality rate from cardiovascular disease. Stress, insulin resistance, and behaviors including alcohol use, smoking, and physical inactivity are all prevalent in lower limb amputees. Other health complications include infection, excessive bleeding, muscle shortening, and pulmonary embolisms.

How Long Is Rehab After Leg Amputation?

Every patient is different, however, the rehabilitation process can last as long as one year.

PrimeCare Orthotics & Prosthetics Can Help!

If you need guidance on above-the-knee prosthetics, our team is here to help! We have a team of caring and qualified practitioners who are dedicated to helping patients in Albuquerque and Las Cruces thrive. Contact us at PrimeCare Orthotics & Prosthetics today!