Overview – Knee replacement
Knee replacement surgery (arthroplasty) is a routine operation that involves replacing a damaged, worn or diseased knee with an artificial joint.
Adults of any age can be considered for a knee replacement, although most are carried out on people between the ages of 60 and 80. More people are now receiving this operation at a younger age.
When a knee replacement is needed
Knee replacement surgery is usually necessary when the knee joint is worn or damaged to the extent that your mobility is reduced and you experience pain even while resting.
The most common reason for knee replacement surgery is osteoarthritis. Other conditions that cause knee damage include:
- rheumatoid arthritis
- disorders that cause unusual bone growth (bone dysplasias)
- death of bone in the knee joint following blood supply problems (avascular necrosis)
- knee injury
- knee deformity with pain and loss of cartilage
Who is offered knee replacement surgery
A knee replacement is major surgery, so is normally only recommended if other treatments, such as physiotherapy or steroid injections, haven’t helped reduce pain or improve mobility.
You may be offered knee replacement surgery if:
- you have severe pain, swelling and stiffness in your knee joint and your mobility is reduced
- your knee pain is so severe that it interferes with your quality of life and sleep
- everyday tasks, such as shopping or getting out of the bath, are difficult or impossible
- you’re feeling depressed because of the pain and lack of mobility
- you can’t work or have a normal social life
You’ll also need to be well enough to cope with both a major operation and the rehabilitation afterwards.
Types of knee replacement surgery
There are two main types of surgery, depending on the condition of the knee:
- total knee replacement (TKR) – both sides of your knee joint are replaced
- partial (half) knee replacement (PKR) – only one side of your joint is replaced in a smaller operation with a shorter hospital stay and recovery period
There are alternative surgeries to knee replacement, but results are often not as good in the long term. Your doctor will discuss the best treatment option with you. Alternatives may include:
- arthroscopic washout and debridement – an arthroscope (tiny telescope) is inserted into the knee, which is then washed out with saline to clear out any bits of bone or cartilage
- osteotomy – during an open operation, the surgeon cuts the shin bone and realigns it so that weight is no longer focused on the damaged part of the knee
- mosaicplasty – a keyhole operation that involves transferring plugs of hard cartilage, together with some underlying bone from another part of your knee, to repair the damaged surface
Choosing a specialist
Choose a specialist who performs knee replacement regularly and can discuss their results with you.
This is even more important if you’re having a second or subsequent knee replacement (revision knee replacement), which is more difficult to perform.
Your local hospital trust website will show which specialists in your area do knee replacement. Your GP may also have a recommendation, or arrange for you to follow an enhanced recovery programme.
Preparing for knee replacement surgery
Before you go into hospital, find out as much as you can about what’s involved in your operation. Your hospital should provide written information or videos.
Stay as active as you can. Strengthening the muscles around your knee will aid your recovery. If you can, continue to take gentle exercise, such as walking and swimming, in the weeks and months before your operation. You can be referred to a physiotherapist, who will give you helpful exercises.
Read about preparing for surgery, including information on travel arrangements, what to bring with you and attending a pre-operative assessment.
Recovering from knee replacement surgery
You’ll usually be in hospital for three to five days, but recovery times can vary depending on the individual and type of surgery being carried out.
Once you’re able to be discharged, your hospital will give you advice about looking after your knee at home. You’ll need to use a frame or crutches at first and a physiotherapist will teach you exercises to help strengthen your knee.
Most people can stop using walking aids around six weeks after surgery, and start driving after about eight to 12 weeks.
Full recovery can take up to two years as scar tissue heals and your muscles are restored by exercise. A very small amount of people will continue to experience some pain after two years.
Risks of knee replacement surgery
Knee replacement surgery is a common operation and most people don’t experience complications. However, as with any operation, there are risks as well as benefits.
Complications are rare but can include:
- stiffness of the knee
- infection of the wound
- deep infection of the joint replacement, needing further surgery
- unexpected bleeding into the knee joint
- ligament, artery or nerve damage in the area around the knee joint
- blood clots or deep vein thrombosis (DVT)
- persistent pain the in the knee
- fracture – a break in the bone around the knee replacement during or after the operation
In some cases, the new knee joint may not be completely stable and further surgery may be needed to correct it.
The National Joint Registry
The National Joint Registry (NJR) collects details of knee replacements carried out in England and Wales. Although it’s voluntary, it’s worth registering. This enables the NJR to monitor knee replacements, so you can be identified if any problems emerge in the future.
The registry also gives you the chance to participate in a patient feedback survey.
It’s confidential and you have a right under the Freedom of Information Act to see what details are kept about you.
Media last reviewed: 14/04/2018
Media review due: 14/04/2021
Page last reviewed: 25/07/2016
Next review due: 25/07/2019
Knee joint replacement
Knee joint replacement is a surgery to replace a knee joint with a man-made artificial joint. The artificial joint is called a prosthesis.
Damaged cartilage and bone are removed from the knee joint. Man-made pieces are then placed in the knee.
These pieces may be placed in the following places in the knee joint:
- Lower end of the thigh bone — This bone is called the femur. The replacement part is usually made of metal.
- Upper end of the shin bone, which is the large bone in your lower leg — This bone is called the tibia. The replacement part is usually made from metal and a strong plastic.
- Back side of your kneecap — Your kneecap is called the patella. The replacement part is usually made from a strong plastic.
You will not feel any pain during the surgery. You will have one of these two types of anesthesia:
- General anesthesia — This means you will be asleep and unable to feel pain.
- Regional (spinal or epidural) anesthesia — Medicine is put into your back to make you numb below your waist. You will also get medicine to make you sleepy. And you may get medicine that will make you forget about the procedure, even though you are not fully asleep.
After you receive anesthesia, your surgeon will make a cut over your knee to open it up. This cut is often 8 to 10 inches (20 to 25 centimeters) long. Then your surgeon will:
- Move your kneecap (patella) out of the way, then cut the ends of your thigh bone and shin (lower leg) bone to fit the replacement part.
- Cut the underside of your kneecap to prepare it for the new pieces that will be attached there.
- Fasten the two parts of the prosthesis to your bones. One part will be attached to the end of your thigh bone and the other part will be attached to your shin bone. The pieces can be attached using bone cement or screws.
- Attach the underside of your kneecap. A special bone cement is used to attach this part.
- Repair your muscles and tendons around the new joint and close the surgical cut.
The surgery takes about 2 hours.
Most artificial knees have both metal and plastic parts. Some surgeons now use different materials, including metal on metal, ceramic on ceramic, or ceramic on plastic.
Why the Procedure is Performed
The most common reason to have a knee joint replaced is to relieve severe arthritis pain. Your doctor may recommend knee joint replacement if:
- You are having pain from knee arthritis that keeps you from sleeping or doing normal activities.
- You cannot walk and take care of yourself.
- Your knee pain has not improved with other treatment.
- You understand what surgery and recovery will be like.
Most of the time, knee joint replacement is done in people age 60 and older. Younger people who have a knee joint replaced may put extra stress on the artificial knee and cause it to wear out early and not last as long.
Before the Procedure
Always tell your health care provider what drugs you are taking, even drugs, supplements, or herbs you bought without a prescription.
During the 2 weeks before your surgery:
- Prepare your home.
- Two weeks before surgery, you may be asked to stop taking drugs that make it harder for your blood to clot. These include aspirin, ibuprofen (Advil, Motrin), naproxen (Naprosyn, Aleve), blood thinners such as warfarin (Coumadin), and other drugs.
- You may also need to stop taking medicines that can make your body more likely to get an infection. These include methotrexate, Enbrel, or other medicines that suppress your immune system.
- Ask your provider which drugs you should still take on the day of your surgery.
- If you have diabetes, heart disease, or other medical conditions, your surgeon will ask you to see the provider who treats you for these conditions.
- Tell your provider if you have been drinking a lot of alcohol, more than 1 or 2 drinks a day.
- If you smoke, you need to stop. Ask your providers for help. Smoking will slow down wound and bone healing. Your recovery may not be as good if you keep smoking.
- Always let your provider know about any cold, flu, fever, herpes breakout, or other illness you have before your surgery.
- You may want to visit a physical therapist to learn some exercises to do before surgery.
- Set up your home to make everyday tasks easier.
- Practice using a cane, walker, crutches, or a wheelchair correctly.
On the day of your surgery:
- You will most often be asked not to drink or eat anything for 6 to 12 hours before the procedure.
- Take the drugs you have been told to take with a small sip of water.
- You will be told when to arrive at the hospital.
After the Procedure
You will stay in the hospital for 1 to 2 days. During that time, you will recover from your anesthesia and from the surgery itself. You will be asked to start moving and walking as soon as the first day after surgery.
Full recovery will take 4 months to a year.
Some people need a short stay in a rehabilitation center after they leave the hospital and before they go home. At a rehabilitation center, you will learn how to safely do your daily activities on your own.
The results of a total knee replacement are often excellent. The operation relieves pain for most people. Most people DO NOT need help walking after they fully recover.
Most artificial knee joints last 10 to 15 years. Some last as long as 20 years before they loosen and need to be replaced again. Total knee replacements can be replaced again if they get loose or wear out. However, in most cases the results are not as good as the first time. It is important not to have the surgery too early so you will need another surgery at a young age or have it too late when you will not benefit the most.
Total knee replacement; Knee arthroplasty; Knee replacement – total; Tricompartmental knee replacement; Subvastus knee replacement; Knee replacement – minimally invasive; Knee arthroplasty – minimally invasive; TKA – knee replacement; Osteoarthritis – replacement; OA – knee replacement
Expert Icing After Joint Replacement Surgery
This article was reviewed by Dr. Nima Mehran, MD, Orthopedic Surgeon
Hate it or love it, icing will become a big part of your everyday routine in the weeks (even months) after joint replacement surgery. Like anything in life, there are decent ways to go about icing, and then there’s expert-level icing. This is like Olympic level icing versus house-league. In this article, we will cover why icing is important, the different methods of icing, and share the best of the best icing tips and tricks for those recovering from hip replacements and knee replacements.
Continue reading to get your ice ice baby on!
Don’t Fall Down a Slippery Slope: Why Icing After Joint Replacement Surgery
Icing is huge part of cutting down pain, swelling and inflammation after surgery. In other words, icing jumpstarts healing and helps to keep you more comfortable as you recover. Icing should be incorporated into your daily recovery routine alongside elevating your surgical leg, taking prescribed pain medications, completing physical therapy, and running through your assigned PeerWell ReHab app checklist.
Different physical therapists and doctors come with varying recommendations for how many times a day you should ice for and how long. Some care providers put a maximum cap on icing, while others suggest you ice as many times a day as you see fit.
In saying this, a good rule of thumb is to ice a minimum of 3-4 times a day for 15-20 minutes at a time. It’s especially important that you ice after therapy and activities or exercises that challenge your range of motion, endurance and so forth. This could even be a longer walk, after an hour of errands and so forth. Know when you’re pushing yourself and be ready for an ice treatment afterwards.
Caution: Fresh ice directly on a limb can burn the skin and reduce blood circulation. This is very painful and bad for healing. For this reason, it’s safest to ice in 20 minute time blocks, with fabric (like a tea towel) protecting your skin from touching ice directly.
How to Ice Properly After Joint Surgery
The best ways to ice are slightly different for those who’ve had a knee replacement (regardless of if it’s a partial or a full replacement) and a hip replacement (again, regardless of replacement type like anterior hip replacement, minimally invasive hip replacement and so forth).
Those Who’ve Had a Knee Replacement
With a knee replacement, you will want to be sure to elevate your leg while icing. This helps cut down swelling and inflammation, which speeds up healing. While icing, lay on your back and prop your surgical leg with 3 or more pillows. DO NOT put pillows directly under your knee as this cause stiffness (the exact opposite of what you want in the first weeks of recovery). Pillows should prop your heel. When icing, keep your knee as straight as possible. Your surgical leg must be elevated higher than your heart.
- Once elevated, ice you 15-20 minutes at a time.
- Wrap ice in a tea towel, t-shirt, or thin cloth. DO NOT apply directly to skin (you may get burned, literally).
- Repeat icing at least 3-4 times a day. If you think you would benefit from icing more frequently, ask your doctor if this is a good idea.
How long to ice a knee after knee replacement surgery? It’s important to keep icing daily in the first 90 days of surgery and beyond. As long as you have pain and swelling, icing is a great tool to overcome these recovery setbacks.
Those Who’ve Had a Hip Replacement
For hip replacement recipients, you will want to elevate your leg slightly (with 1-2 pillows) and lay with your surgery side up to ice. This reduces swelling and will likely be a more comfortable position.
- Once elevated, ice you 15-20 minutes at a time.
- Wrap ice in a tea towel, t-shirt, or thin cloth. DO NOT apply directly to skin.
- Repeat icing at least 3-4 times a day. If you think you would benefit from icing more frequently, ask your doctor if this is a good idea.
Tip: Remember, icing to reduce pain and speed up recovery is apart of a “triple approach” (in show biz, they call this a triple threat): pain medication, elevation and icing. Doing all 3 will keep pain down and allow you to recover safely, with a lessened chance of complications due to excessive swelling, bruising or inflammation.
Best Icing Methods After Surgery
Crushed Ice in a Bag
An easy-to-make go-to is to take about 1-2 cups of crushed, shaved ice or ice cubes and put it into a ziplock bag. You can add saran wrap to around the bag to keep the ice block more dense, therefore making it last longer.
This method of icing works perfectly well for 20 minutes on but the ice will melt faster.
Foam Cups/ Pucks
Rather than filling up an endless supply of ice cube trays and whipping through them, we suggest making larger, cups with ice. These will last much longer and have a larger surface area to ice your joint.
To make, simply buy foam drinking cups from your local grocer, dollar store, or order online. All sizes work, but we recommend going with the 10-12 oz size.
Instant Ice Packs
Instant ice packs are great for on-the-go when you’re further along in your recovery and more mobile. If you’re heading to appointments, out to run errands, or are in the car for a prolonged period, dry instant ice packs are perfect. Instant ice packs do not have to be frozen or refrigerated. Simply, squeeze the center of the pack and it will instantly get ice cold. These packs last a couple of hours.
Find these instant cold packs at your pharmacy or order online.
Ice Therapy Machine
Ice therapy machines (also called cold therapy machines) can be costly but some pharmacies, hospitals and therapy offices rent them out. Finding an ice machine for knee surgery rental or after hip surgery may be easier than you think, so ask around locally. Some ice therapy machines with a cuff are better designed for the knee joint, so if you’ve had a hip replacement, make sure the attachment will work for you. Like ice, these machines provide pain relief, and reduce swelling and tissue damage.
Ice therapy machines can be motorized or nonmotorized and offer direct cold treatments to specific areas of the body. The machines circulate cold water and air through a wrap that you put on your joint. Since they do not get as cold as ice, they can be left on longer. Usually, the recommendation is to leave them on for two hours at at time. However, some replacement candidates report leaving them on throughout the night and swear by them for a faster recovery. If you do leave it on during the night, ask your doctor and always remember to keep your skin completely covered to avoid burns.
Gel or Ice Packs
Gel packs (or ice packs) are kind of like the superior frozen bag of peas or even homemade ice puck. Like a pouch alcoholic drink you put in your freezer during summer vacation, gel packs never freeze completely. They remain kind of slushy, which is great for shaping around your entire joint area. Like ice cubes or pucks, gel packs should be wrapped in thin cloth while fresh. They can be put directly on the skin once they have warmed up a bit.
Gel packs can be purchased at your local pharmacy, department stores, or in bulk online. Better yet, read on and we will show you how to make your own. It’s cheap and easy!
DIY Gel Pack Recipe
What you will need:
- 1 large bottle of rubbing alcohol (at least 34 ounces or 1 litre)
- Gallon sized freezer bags
- Tap water
What to do:
- Take a large freezer bag and measure about 8 cups of tap water. Dump water into bag.
- Measure out 2 cups of rubbing alcohol. Add this into the bag with water.
- Squeeze out air in freezer bag and seal. To avoid any leaks, place sealed bag into a second freezer bag and seal this one too.
- Stick your homemade ice pack in the freezer for about 8 hours.
Tip: Make at least 2-3 gel packs so that you always have “fresh”, cold ones ready to cycle out. Once the gel pack has thawed, place back in the freezer and reuse.
There you have it. Now you’ve heard everything you need to know (and then some) about icing after joint replacement surgery. Actively staying on top of what your doctor and physical therapist recommends, as well as following an at-home ReHab program (like PeerWell) will get you recovered faster. Although there will be some ups and downs, the more dedicated you are to your recovery, the better it will go.
Are you having joint replacement surgery? Have you just had a hip replacement or knee replacement? If so, sign-up for PeerWell. Our PreHab and ReHab app is designed to deliver better surgery outcomes for joint replacement candidates and guides recipients through a faster and safer recovery.
Hi, I’m Grace. I write and research about hip and knee replacements, PreHab before orthopedic surgery & ReHab. Content advised or co-authored with physicians (MD) and orthopedic surgeons (OS).
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