Total Knee Replacement Surgery

As you age throughout life, your knee may become severely damaged by arthritic change or an injury. As a result, it may be hard for you to perform simple everyday activities such as walking or climbing stairs. Your knee may even become problematic at rest, where you feel pain while you rest at night or just sitting.

It is always important to try conservative measures to manage your knee pain and loss of function. If conservative treatments such as exercising, medications and using walking supports are not helpful, you may want to consider undergoing a total knee replacement. Joint replacement surgery has been around for many years and is relatively safe and effective procedure to help relieve your pain, correct any leg deformity, and can help you resume a better lifestyle.

The first knee replacement surgery was first performed in 1968. Over the years, improvements have been made in surgical materials used and techniques have improved, increasing the effectiveness of this type of surgery. Total knee replacements are one of the most successful procedures in all of medicine. According to an article in the Financial Review around 70,000 knee replacements are performed annually in Australia in 2022. It is estimated around an 85% satisfaction post-surgery and that surgery should not be performed on mildly arthritic knees.

If you have just begun exploring your treatment options for your knee dysfunction or have already decided to have a total knee replacement, hopefully this article will help you understand more about this surgical procedure.

Anatomy of the knee

The knee is a hinge type joint and the largest joint in the human body. To perform most everyday activities it is important to have healthy knees to move well.

Healthy knee joint anatomy

In a healthy knee joint, the structures work together to ensure smooth movement and normal functioning of the knee joint.

The knee joint is made up of the lower end of the thigh bone (femur), the upper end of the shin bone (tibia), and the kneecap (patella). All three bones are covered with articular cartilage at their ends, which is a smooth substance that protects the bones and enables them to move easily within the joint.

The menisci are located between the thigh bone (femur) and shin bone (tibia). These C-shaped wedges act as shock absorbers that help cushion the joint.

There are four large ligaments that hold the femur and tibia together and help provide stability to the knee joint. The long thigh muscles such as the quadriceps and hamstrings provide the knee joint strength.

Underlying the knee joint capsule, a thin lining called the synovial membrane exists. This membrane releases synovial fluid that helps lubricate the cartilage, reduces friction to nearly zero in a healthy knee.

In a healthy knee joint, all these components work together in harmony. However, when disease or injury disrupt the harmony of the knee structures, resulting pain, swelling, muscle weakness, and loss of function may arise.

Causes of knee dysfunction

The most common cause of chronic knee pain and loss of function is knee arthritic change. There are many types of knee arthritis, but most knee pain is caused by the following three types of knee arthritis:

Osteoarthritis

This tends to happen with age-related wear and tear of the knee joint. It usually occurs in people over 50 years of age and beyond, but occasional can affect younger people, may be as a result of a disease. The hyaline cartilage that cushions the bones of the knee joint softens and starts to wear away. Over time the bones then rub against one another, causing knee pain, swelling and stiffness. With prolonged bony irritation, osteoarthritis can often result in bony spurs on the joint margins causing further disability. GLA:D is an exercise and education program developed  in Denmark for people with knee or hip osteoarthritis.  Marc Rahme is our GLA:D certified practitioner. For more information regarding the program- click here.

Rheumatoid arthritis (RA)

Rheumatoid Arthritis is a disease which attacks the synovial membrane that surrounds the joint, causing it to become inflamed and thickened. This chronic inflammation leads to damage of the cartilage and eventual cartilage loss causing pain, stiffness and loss of function. Rheumatoid arthritis is the most common type in a group of disorders termed “inflammatory arthritic disorders.”

Post-traumatic arthritis

This type of arthritic change often occurs a serious knee injury, where the intra-articular structures of the knee joint are damaged severely. Fractures of the bones forming the knee or tears of the knee ligaments may lead to damage of the articular cartilage over time, causing longer term knee pain and limited knee function.

What is knee replacement surgery?

Knee replacement surgery can often be referred to as knee arthroplasty. This term is misleading as this involves only the surface of the bones forming the knee joint being replaced. Knee arthroplasty involves cleaning up of the knee joint in minor cases of degenerative wear. There are four basic steps to knee replacement surgery:

Preparing the bone. The damaged cartilage surfaces and underlying bone at the ends of the femur and tibia are removed, exposing healthier bone tissue.

Positioning the metal implants. Once the damaged cartilage and bone is removed, it is replaced with metal components that recreate the new artificial surface of the joint. These metal components are cemented and press-fit into the healthy bone.

Resurfacing the patella. The under surface of the patella (kneecap) is cut away and resurfaced with a plastic button. Not all surgeons resurface the patella, it depends upon the individual case.

Inserting a spacer. In knee replacement surgery a medical-grade plastic spacer is inserted between the metal components to create a smooth gliding surface.

Are you ready for total knee replacement?

The decision to have total knee replacement surgery is a very personnel decision, but you need to be well informed about the procedure and outcome. Often the decision will be a cooperative one between you, your family, your primary care doctor, and your orthopaedic surgeon.

Your doctor may refer you to an orthopaedic surgeon for a thorough evaluation and opinion as to determine whether you might benefit from knee replacement surgery. Ultimately the decision comes down to the individual and if they feel they are ready to undergo the surgery.

When surgery is recommended

There are several reasons why it may be recommended that knee replacement surgery is needed. People who benefit from total knee replacement will often present with the following:

Severe knee pain or stiffness that restricts everyday activities, such as walking, climbing stairs, and getting in and out of chairs. They find it increasingly hard to walk more than a few hundred metres without significant pain and it may be necessary to use a support like a stick or frame.

They develop moderate or severe knee pain while resting, either during the day or at night. Chronic knee inflammation and swelling that does not improve with rest, ice or medications. When knee deformity arises such as bowing in or out of the knee.

Failure to improve significantly with conservative treatments such as anti-inflammatory medications, cortisone injections, lubricating injections, physiotherapy, or other minor surgery.

Who are candidates for surgery?

There is no limit on age or weight restrictions for undergoing a total knee replacement surgery. Generally, it is recommended surgery is based on a patient’s pain and loss of function, not their age. The biggest population who undergoes total knee replacement are aged between 50 to 80, but orthopaedic surgeons evaluate patients on an individual basis. Total knee replacements have been performed successfully at all ages, from the teenagers with juvenile arthritis to the older patients with degenerative arthritis.

Orthopaedic Evaluation to determine if you are suitable for surgery

An evaluation with an orthopaedic surgeon will consists of several components such as medical history. Your surgeon will gather information about your general health and ask you about the severity of your knee pain and ability to function.

Physical examination will assess your knee movement, stability, strength, and knee alignment.

X-rays images may help to determine the extent of damage and deformity in your knee. Occasionally blood tests or advanced magnetic resonance imaging (MRI) scanning may be needed to determine the condition of the bone and soft tissues of your knee.

Your orthopaedic surgeon will review all the results of your evaluation and discuss whether knee replacement surgery is the best choice to relieve your severe pain and improve your function.

Finally, if surgery is decided your orthopaedic surgeon will explain the potential risks and complications of total knee replacement.

Deciding to Have Knee Replacement Surgery – have Realistic Expectations

An important factor in deciding whether to have total knee replacement surgery is understanding what the procedure does. Most people who undergo total knee replacement surgery experience a dramatic reduction of their knee pain and significant improvement in their daily function. Post knee joint replacement will not mean you can do more than you could before you developed severe arthritis.

Like a normal knee, with use and activity every knee replacement implant begins to wear in its plastic spacer. Excessive loading or weight may speed up this wear and may cause your knee replacement to become loose and painful. Most surgeons advise against high-impact activities such as running, jumping, or other high-impact sports for the rest of your life after surgery.

Relatively safe activities following knee replacement include walking, swimming, golf, light hiking, biking and other low-impact sports.

Possible complications of surgery

The complication rate following total knee replacement is relatively low. A serious complication, such as a knee infection, occur in less than 2% of patients. Major medical complications such as heart attack occur even less frequently. Patients suffering from chronic illness may have increase potential for complication, any your concerns should be thoroughly discussed with your orthopaedic surgeon prior to surgery.

Infection may occur in the wound or deeper around the prosthesis. It can happen within days or weeks after your surgery. Minor infections in the wound area are treated with antibiotics. If a major or deep infection occurs, then you may require more surgery and removal of the prosthesis.

Blood clots in the leg veins are one of the more common complications of knee replacement surgery. Clots can be life-threatening if they break free and travel to your lungs causing pulmonary embolism. Your orthopaedic surgeon may undertake preventative precautions, including regular elevation of your legs, lower leg exercises to increase circulation, compression stockings, and medication to thin your blood.

Surgery

The surgical procedure usually takes anywhere from 1 to 2 hours. Your orthopaedic surgeon will remove the damaged cartilage and bone in your knee. Next steps are to position the new metal and plastic implants to restore and improve the alignment and function of your knee joint.

After surgery, you will be taken to the recovery room, where you will remain for several hours as your recover from the effects of anaesthesia. Once you are awake and alert, you will be taken to your hospital room if staying overnight or discharged home.

Post surgery

After surgery, you will feel pain being a natural part of the healing process. Your doctor and nurses will work to help reduce your pain with medication, which will help you recover from surgery better.

Medications are often prescribed in the short-term for pain relief after surgery. Medicines that are available to help manage pain, include opioids, non-steroidal anti-inflammatory drugs (NSAIDs), and local anaesthetics. You may be given a combination of these medications to improve pain relief, and to help minimise the need for opioids.

Opioids can help relieve pain after surgery, but they are a narcotic and can be addictive. It is important to use opioids only as directed by your doctor and for as short as possible. Talk to your doctor about your options if your pain has not improved within a few days of your surgery.

Physiotherapy

Most patients can begin exercising their knee within hours after surgery. A physiotherapist will teach you exercises to regain knee movement and strengthen your leg to get you back up walking and doing other daily activities soon after your surgery.

In some cases, your surgeon may restore movement in your knee post-surgery by using a device called continuous passive motion. The continuous passive motion device will help with knee support, whilst allowing slow motion of your knee, while you are in bed.

Some surgeons believe that a continuous passive motion machine decreases leg swelling by elevating your leg and improves your blood circulation by moving the muscles of your leg, but there is no evidence that these machines improve outcomes.

Your recovery at home

Wound care

Down the front of your knee, you will have stitches or staples running along your wound or sutures beneath your skin. The stitches or staples tend to be removed several weeks after surgery. If sutures are placed beneath your skin, these will not require removal.

It is essential to avoid soaking or getting the wound wet until it has thoroughly sealed and dried. You may continue to bandage your wound to prevent irritation from your clothing or support stocking.

Physical activity

Your surgery will only be good as you exercise program, which is a critical component of home care and recovery, particularly during the first few weeks post-surgery. You should get back to most activities of daily living within the first 3 to 6 weeks following surgery. It is typical to feel some pain with activity and at night for several weeks after surgery.

Your post-operative exercise program should include:

A graduated walking program to slowly increase your mobility. You should start initially in your home and later progress to outdoors as your confidence grows.

Resume as soon as possible to other household activities, such as sitting, standing, and climbing stairs.

Specific exercises several times a day to help restore movement and strengthen your knee. When at home you will probably be able to perform the exercises without any help. In very senior patients, they may have a physiotherapist help them at home or in a care centre for the first few weeks after surgery. At Lilyfield Physio, we are experienced in physio for knee replacement to help you with your recovery.

Before you resume driving you should get medical clearance from your doctor. This can be considered, once your knee bends enough that you can enter and sit comfortably in your car, and when you have adequate muscle strength to apply adequate reaction time for braking and acceleration. Most people will resume driving approximately 4 to 6 weeks post-surgery.

Avoiding problems after surgery

Recognizing the signs of a blood clot

Follow your surgeon’s instructions carefully to reduce your risk of blood clots developing during the early stages of your recovery. They may recommend that you continue taking the blood thinning medication and wearing support stocking to help circulation. If you develop any of the following warning signs notify your doctor immediately:

The warning signs of possible blood clots in your leg include increasing pain in your calf, tenderness or redness above or below your knee, new or increasing swelling in your calf, ankle, and foot.

The warning signs that a blood clot has travelled to your lung (pulmonary embolism) include a sudden onset of shortness of breath, sudden onset of chest pain and localised chest pain with coughing.

Preventing infection

Common causes of infection following total knee replacement surgery are from bacteria that enter the bloodstream from dental procedures, urinary tract infections, or skin infections. The bacteria can enter your knee replacement and cause an infection.

After knee replacement, some patients with certain risk factors may be required to take antibiotics prior to dental work, or before any surgical procedure that could allow bacteria to enter the bloodstream. Your orthopaedic surgeon will discuss with you whether you need to take preventive antibiotics.

Warning signs of a possible knee replacement infection include persistent fever (higher than 100°F orally), chills, increasing redness, tenderness, or swelling of the knee wound. Drainage from the knee wound and increasing knee pain with both activity and rest. Any signs see your doctor immediately.

Avoiding falls

Care must be taken to avoid falling during the first few weeks post-surgery, as this can damage your knee replacement and require further surgery. Stairs can be a particular hazard until your knee is much stronger and mobile. Get help until you have improved your balance, flexibility, and strength.

Outcomes

How your new knee is different

It is hoped improvement of your knee motion is a goal of your total knee replacement, but restoration of full motion is uncommon. Generally, the motion of your knee after surgery can be predicted by the range of motion you have prior to surgery. Most patient’s outcome is to be able to almost fully straighten the replaced knee and to bend the knee enough to climb stairs and get in and out of a car. Kneeling generally is uncomfortable, but it is not unsafe or harmful.

Numbness in the skin around their incisions is very common. Initially you may feel some stiffness, particularly with excessive bending activities.

It is normal for most people to feel or hear some clicking of the metal and plastic components within the knee when bending or walking. This often diminishes with time and most patients find them to be tolerable when compared with the pain and limited function they had.

Protecting your knee replacement for the future

Ensure you participate in regular light exercise programs to maintain proper strength and mobility of your new knee. Take care and try to avoid falls and injuries.

Always let your dentist know that you have a knee replacement. You may need to talk with your orthopaedic surgeon about whether you need to take antibiotics for dental procedures.

It is important to have follow up consultations with your orthopaedic surgeon periodically. Your surgeon will talk with you about the frequency and timing of these routine examinations.