Total Knee Replacement
When your knee is significantly damaged by arthritis or injury, it may be hard for you to perform even basic activities such as walking or climbing the stairs. You may start to suffer from pain even while you are sitting or lying down, which can significantly affect your quality of life.
The first-line treatments for chronic knee pain are physical therapy, lifestyle changes and medication. But when these approaches fail to provide relief, your doctor may recommend Total Knee Replacement. This surgical procedure can be your second chance at living a normal and active life free of chronic pain.
At the Orthopaedic Institute of Ohio, our doctors have performed countless knee replacements and witnessed the life-altering impacts this procedure provides.
What Is Total Knee Replacement?
Total knee replacement is the complete reconstruction of the knee joint. Also known as knee arthroplasty or knee resurfacing, it is a type of surgical procedure in which orthopedic surgeons remove the surface of the knee joints and replace them with a prosthesis, which is usually composed of metal or ceramic implants and medical-grade plastic spacers.
The procedure is done to relieve chronic knee pain and restore functioning in patients with significant damage to the knee joint who do not respond to conservative treatment. The most common cause of chronic knee pain is osteoarthritis. However, knee pain can also result from injuries, rheumatoid arthritis and gout, among other things.
This procedure has a long history, dating back to the 1800s when surgeons used ivory to replace damaged knee joints. Advancements in orthopedics over the past three decades have helped make this one of the most successful procedures. According to data from the Agency for Healthcare Research and Quality, about 700,000 knee replacements are performed each year.
Total knee replacement is usually an inpatient procedure, requiring hospital stays of at least two to three days. It is done under general, local or epidural anesthesia with sedation. The procedure typically takes one to three hours to complete, depending on whether you’re having one or both knees replaced.
Overview of the Knee
The knee is the largest, most complex and likely the most stressed joint of the body. This makes it prone to wear and tear over time, as well as injury.
The knee joint joins together four bones:
- Thighbone (femur)
- Shinbone (tibia)
- Calf bone (fibula)
- Kneecap (patella)
The ends of these bones are covered with cartilage, connective tissue that reduces friction during movement. Another pad of cartilage called the meniscus is found between the knee joint meeting points and works as a shock absorber. The knee also contains a synovial membrane that seals the joint into a capsule and produces clear, sticky synovial fluid to provide lubrication. Ligaments, tendons and muscles protect the joint by limiting movement while allowing the knee to operate normally.
The knee can further be divided into three compartments:
- Medial compartment, or the inside of the knee
- Lateral compartment, or the outer part of the knee
- Patellofemoral compartment, or the front part of the knee
When any of the components of the knee become diseased or damaged, the knee will not function properly. This diminished function can lead to discomfort and limited motion of the joint. In severe cases, knee damage can lead to chronic pain and interfere with basic day-to-day functioning.
Replacing a portion (partial knee replacement) or the entire knee joint (total knee replacement) can restore normal movement and eliminate pain to improve the patient’s quality of life. While partial knee replacement is effective for a small number of patients, total knee arthroplasty is much more commonly performed and ensures the best possible result.
How Is Total Knee Replacement Done?
A total knee replacement involves resurfacing of all three compartments of the knee. In other words, this surgical procedure resurfaces the ends of the thigh bone, shinbone and kneecap.
The procedure is done under anesthesia, either general or local. The knee is put into a bent position to make all parts of the knee joint easier to access. Your surgeon then makes a long incision of six to 10 inches across the front part of the knee. The surgeon rotates the kneecap to gain access to other parts of the knee joint and removes damaged cartilage and bone from the femoral compartment. Precise cuts with special instruments are made to fit the prosthesis.
The next step is implanting the prosthesis. The surgeon attaches the metal component to the prepared femur bone and seals it with bone cement. The surgeon then removes the damaged components from the shinbone and places an implant part called the tibial tray. A medical-grade plastic insert is placed on top of the tibial tray to provide shock absorbency.
Finally, the surgeon may need to cut away parts of the kneecap and attach a plastic component to it to make it fit the new joint. Your surgeon will check the implant before closing the incisions with staples or stitches. The knee is covered in surgical dressing, and you are moved to the recovery room.
When Is Total Knee Replacement Done?
Total knee replacement is recommended to patients suffering from chronic knee pain who do not respond to other treatments. There are different reasons why chronic knee pain might occur. Common causes of damage to the joint include:
Osteoarthritis
Osteoarthritis is the most common condition causing chronic knee pain and resulting in the need for total knee replacement. This condition is characterized by stiffening of the joint due to long-term use and is frequently diagnosed in people over the age of 50. However, a small number of younger patients may suffer from osteoarthritis as well. The condition is a result of the deterioration of the cartilage around the bones, allowing the bones to fret directly against one another. Loss of cartilage can lead to pain and stiffness, as well as damage to the bone if it is left untreated.
Rheumatoid Arthritis
This autoimmune disorder causes chronic inflammation of the knee joint, which eventually leads to loss of cartilage, reduced motion and pain. Rheumatoid arthritis does not have a cure at this time and is a progressive disease, which means symptoms tend to worsen over time. If the condition is severe enough, only total knee replacement can provide relief and restore normal knee functioning.
Post-Traumatic Arthritis
This arthritis occurs after an injury to the knee, such as bone fractures and ligament tears. Even if the original injury heals, it can cause damage to the cartilage of the joint, leading to friction between the bones, pain and motion limitations over time. This type of damage can be irreversible, and the only effective mode of treatment is knee replacement surgery.
Usual candidates for total knee replacement are older adults between 50 and 80 years of age. This patient group is less likely to require Revision Knee Replacement because they are less likely to cause excessive wear and tear on the prosthesis. Younger patients, and especially if they have partial damage of the knee, can benefit from partial knee replacement.
Is Total Knee Replacement Right for You?
Most people with osteoarthritis do not require surgery and can manage their condition with lifestyle changes, physical therapy, occupational therapy, pain medication and injections. But if you’ve tried countless treatments and still find that your knees hurt and severely limit movement, your doctor may refer you to an orthopedic surgeon.
Orthopedic surgeons will recommend total knee replacement only if:
- You have tried conservative treatments without success
- You have knee pain most or all of the time
- You are unable to perform everyday tasks due to pain
- You have poor limb alignment
- Your condition is causing you anxiety and depression
- Your knee gives way or locks up
Conservative treatments include weight loss, changing activity, pain medication (NSAIDs), corticosteroid injections and physical therapy. There is no age limit for total knee replacement. We’ve performed this procedure on teenagers with juvenile idiopathic arthritis, as well as adults over 80 years of age. Most people in relatively good health can be candidates for this procedure.
Your Implant Options
A handful of implant manufacturers make up the majority of knee replacement implants used in the US: Arthrex Inc., Zimmer-Biomet, DePuy Synthes, Stryker Corporation and Smith & Nephew.
The basic structure of most knee implants consists of a metal femoral component that attaches to the femur as well as a tibial component that connects to the end of the tibia. Between the two lies a plastic spacer that is constructed of polyethylene. There are a variety of different implants within this basic structure that allow your surgeon to tailor your procedure to your precise needs. Some of the factors that will be considered when choosing the right implant for you include your anatomy, the degree of your damage and the stability of your ligaments.
Preparing for Total Knee Replacement
If your orthopedic surgeon believes you may be a good candidate for total knee replacement, they will perform a physical examination to confirm that you are healthy enough to undergo this procedure and determine the best course of action.
Blood tests and urinalysis are usually required before this procedure. If you are currently on any medication, you may either need to discontinue it or adjust accordingly.
You will need to take time off from work, possibly several weeks for your recovery. Although you will likely be able to walk using crutches immediately after surgery, it will still take time before you are steady on your feet. Arranging post-surgery help around the home is a good idea.
Knee Replacement Surgery Overview
Your surgeon may perform your knee joint replacement under general or regional anesthesia. Either way, you should be completely comfortable throughout the process. Incisions are made on the front of the knee to access the joint, and damaged cartilage and bone are removed. The bone is then prepared for the application of the prosthesis, and the components are attached. Your surgeon will bend and straighten the knee to ensure the implant works before closing the incision. Most knee replacement surgeries take between 60 and 90 minutes to complete, depending on the complexity of the operation.
Total Knee Replacement Recovery
You will spend a day or two in the hospital so that you can be monitored and cared for during the initial recovery period. Medication will help to minimize discomfort, and blood-thinning medications will reduce your risk for blood clots after surgery. You will also wear compression socks after your procedure for this purpose.
Movement of the foot and ankle is encouraged, and you will be given physical therapy exercises to do before you leave the hospital. You will need to do these exercises regularly to strengthen and restore motion to the joint as it heals. In addition to your home exercises, you will attend supervised physical therapy sessions each week where your therapist can track your progress and assign new exercises as appropriate.
The length of your recovery will depend on how well you adhere to your rehabilitation program and how quickly your body heals. Most patients get around with a walker or crutches for about two to three weeks and then graduate to a cane for an additional couple of weeks. Unassisted walking can typically resume around four weeks.
How Long Does a Knee Replacement Last?
A fairly recent systematic review and meta-analysis of case series and national registry reports found that over 80% of total knee replacements last 25 years. Knee replacement implants can deteriorate with time and repeated use, requiring revision surgery. You can extend the life expectancy of your implant by sticking to recommendations provided to you after surgery.
Most patients who have total knee replacement are older adults, with the mean age for this surgery being around 65 years old. That means that most patients who receive this surgery will not require a revision during their lifetime.
However, some patients develop complications that may require revisions. Complications include loosening of the implant, instability due to improper alignment, infections and injury.
Is Total Knee Replacement Covered by Insurance?
Most insurance companies cover total knee replacement because this is considered a medically necessary procedure. These companies will cover most of what goes into this procedure, but you may also have out-of-pocket expenses. To be insured for knee replacement, you may require your primary care doctor to write a referral to an orthopedic surgeon.
Items that are typically covered by insurers include:
- The initial appointment and evaluation
- Pre-surgery testing and examination
- The surgery, which includes anesthesia, implant and doctor fees
- Follow-up visits and aftercare
- Equipment to help with your recovery
Raising Your Quality of Life
Knee joint replacement is an investment of time but can have a profound impact on your quality of life overall. More than 90 percent of patients who undergo this procedure experience significant or even complete relief from chronic knee pain. To learn more or find out if you are a candidate for total knee replacement, contact the Orthopaedic Institute of Ohio today at 419-222-6622.