Artificial joints (knee, hip)

Last updated date: 10-Jul-2023

Originally Written in English

Artificial joints (knee, hip)

 Artificial joints (knee, hip)


Arthritis, traumas, and other factors such as obesity can all cause joint deterioration. The joint may wear down due to arthritis or just years of usage. This frequently results in discomfort, stiffness, and edema. Diseases and injury inside and around a joint can restrict blood flow, resulting in difficulties in the bones, which require blood to be healthy, develop, and mend.


What is Artificial joints? 

Artificial joints

A prosthesis or prosthetic joint composed of plastic, ceramic, or metal that is implanted to replace a damaged or diseased natural joint is known as an artificial joint.

Each year, more than 600,000 knees and around 400,000 hips are replaced in the United States, according to the American Academy of Orthopaedic Surgeons. Joint replacement surgery involves the removal of a damaged joint and the insertion of a new prosthetic replacement. A joint is formed when two or more bones, such as the knee, hip, or shoulder, come together. An orthopedic surgeon is generally the one who performs the procedure. Sometimes the surgeon will merely replace or repair the damaged components of the joint rather than removing the entire joint.

Depending on your level of discomfort and mobility, the doctor may recommend a partial or total joint replacement to improve your quality of life. A joint replacement can decrease discomfort and help you move and feel better. Hips and knees are two of the most often replaced joints. Shoulders, fingers, ankles, and elbows are among the other joints that can be replaced.

It is crucial to remember that joint replacement surgery is not for everyone who has joint discomfort, since your joints must be damaged in order to be a candidate for this invasive process. That being said, the use of this technique is becoming more common, and it may represent a significant improvement in the quality of life for patients suffering from chronic pain caused by a damaged or diseased joint.

Doctors suggest physical therapy to strengthen bones, muscles, and the new joint to ensure a successful and long-lasting joint replacement. Other suggestions include keeping a healthy weight, cross training to avoid overdoing one sort of exercise or sport, and spending extra time warming up and allowing muscles and joints to recuperate between activities.


Hip and knee replacement surgery

Hip and knee replacement surgery

Hip and knee replacement surgery involves the replacement of worn-out bone and cartilage lining your hip or knee joint with new implants made of ceramic, metal, and plastic. The materials used in hip and knee replacements are nearly identical.

The number of complete hip replacements performed in the United States has gradually climbed over the previous two decades. This spike in surgery has been accompanied by the dissemination of knowledge via the news, social media, films, and the internet. If you're thinking about having hip or knee replacement surgery, it's important to get the facts from reputable sources.




A joint is formed when the ends of two or more bones come together. Within the body, there are several types of joints. The knee, for example, is classified as a "hinge" joint due to its capacity to bend and straighten like a hinged door. The hip and shoulder are "ball-and-socket" joints, with one bone's rounded end fitting into another bone's cup-shaped section.


What are Joint Replacements Made of?

Total Hip Replacement Materials

Total Hip Replacement Materials

Standard total hip replacement implants are typically made up of approximately four individual components:

  1. Stem—inserts into the femur or thigh bone
  2. Cup—inserts into the pelvic bone
  3. Ball—fits onto the end of the stem
  4. Liner—inserts into the cup—essentially becomes your new cartilage


The Stem

The femoral stem is the part of the replacement that is inserted into your thigh bone. Historically, cobalt-chromium and/or titanium metals were used. Cemented stems (inserted with an epoxy bone cement) in current hip replacements are made of cobalt-chromium metals. Titanium is commonly used to make cementless stems (implants in which your bone develops into the metal). As part of complete hip replacement systems, both designs have had outstanding long-term success.

  • Titanium and cobalt-chromium implants are both regarded highly biocompatible, which means they are well tolerated by the human body and provide little danger of adverse response. Both polymers have been demonstrated to be quite efficient in adhering to bone.
  • The femoral stem's upper end (called the trunnion) is particularly designed to hold the artificial joint's new ball. This is where the head and stem join together, regardless of the substance of the ball.


The Cup

The acetabulum (cup) structure is made of various metals and fits into your pelvis. Most modern cups are made of titanium or tantalum metals. Both metals are readily tolerated by human bone and serve as effective bony attachment sites.

  • The steel cups retain the liner of the hip replacement, which is effectively a cartilage replacement.
  • In certain circumstances, a plastic liner can be utilized instead of a metallic cup and is kept in place with epoxy bone cement.


The Ball

The femoral head (ball) is attached to the stem (trunnion). This end of the stem is tapered, allowing the ball to wedge into place and be held snugly in place by friction. The diameter of the ball varies according to the size of the cup that fits into the pelvis. The ball can be formed of a variety of materials, including:

  • Ceramic Many people refer to this as a porcelain substance. This is a very hard surface that is very resistant to scratching and other forms of damage. Ceramic heads can be used in conjunction with either ceramic or plastic liners.
  • Cobalt-chromium This has been the most popular material used for the ball for the most part of the previous three decades since it is relatively scratch resistant and holds up well (similar to ceramic described above). Plastic or metal liners can be used with cobalt-chromium heads. Because of recent concerns about metal debris development when cobalt-chromium heads are used with metal liners, cobalt-chromium heads are now most usually utilized with plastic liners rather than metal liners.


The Liner

The acetabular liner is inserted into the cup and acts as new cartilage. It is subject to wear, much like the cartilage in your own hip, and has historically been the "weak link" in total hip replacement. Early versions of the liner were prone to wear from ball contact and were expected to last just around ten years. Modern advancements have made liners last longer by employing different materials or reinforcing the plastic.

  • Ceramic As previously stated, ceramic is an extremely robust material with low wear rates when combined with a ceramic ball.
  • Cobalt-chromium Over the last decade, metal liners have gone out of favor when used with metal balls; however, newer solutions in which a plastic ball is put in a metal liner (known as dual mobility) have demonstrated outstanding short-term outcomes in the United States and may be effective when used in select individuals.
  • Polyethylene By far the most frequent material utilized for hip replacement liners is plastic. When combined with ceramic or cobalt-chromium balls, this material has produced satisfactory to exceptional results. Over the last 10-15 years, innovations in polyethylene manufacture have dramatically reduced the wear rates of these plastic liners.

When it comes time for a total hip replacement, you should discuss with your surgeon the options and pros and cons of each material. You can make the greatest selection for your specific scenario if you work together. While no surgical technique is without risk or promises 100 percent success, total hip replacement is one of the most successful operations in orthopedics. Many studies have shown that hip implants can persist for more than 15 years after the first operation.


Total Hip Replacement Materials

Total Hip Replacement Materials

Total knee replacements are made of 4 parts as well:

  1. Femur (thigh)—top part
  2. Tibia—(shin) bottom piece
  3. Liner—serves as your new cartilage
  4. Patella (kneecap)—this is an optional part of the surgery, and some physicians do not use this as part of the procedure.


The Femur

Cobalt-chromium is commonly used because it is scratch resistant and safe for use in total knee replacements. With good long-term success rates, the majority of complete knee femoral components are constructed of cobalt-chromium. Titanium is frequently too soft (scratches readily) to be used as a femoral component in the knee, and ceramics play a significantly lesser part in surgeries performed in the US.


The Tibia

Made from titanium or cobalt-chromium, with outstanding results in both cases. This section of the replacement will contain the plastic liner. Some tibial components are entirely constructed of plastic.


The Polyethylene (plastic) liner

This is your new cartilage, and it covers the gap between the two metal parts. As with the total hip replacement, this is the "weak link" that may wear out over time.


The Patella “button”

If your surgeon chooses this option, the undersurface of the patella (knee cap) can be covered with a piece of plastic. This is optional, and not all surgeons utilize it on a regular basis.

Total knee replacement has an excellent success rate, with current implants projected to last between 15-20 years. Total knee replacement, like hip replacement, has been one of the most successful orthopedic surgery in terms of restoring function and quality of life. Total knee replacements have grown in popularity during the previous two decades, outpacing hip replacements (nearly a 2:1 ratio). Although ceramics are not commonly used in knee implant materials in the United States, the fundamental components are the same for both hip and knee replacements.


Who needs Artificial joint replacement?

Artificial joint replacement

Your surgeon may recommend arthroplasty if you have:

  • Nonsurgical therapies such as physical therapy (PT), medicines, bracing, injections, walking assistance devices, and rest have not alleviated joint discomfort.
  • Joint stiffness and reduced mobility make it difficult or impossible to carry out daily tasks.
  • Inflammation (swelling) that does not improve with drugs or lifestyle modifications.


These symptoms can result from several conditions, including:


Preparing for Surgery

Your surgical team and primary care doctor will spend time preparing you for your planned treatment in the weeks leading up to your surgery. For example, your primary care physician may examine your overall health, and your surgeon may order many tests, like as blood tests and a cardiogram, to aid in the planning of your operation.

You may also prepare in a variety of ways. Consult with your doctor and ask questions. Prepare physically by eating well and exercising. Arrange for aid and get assistive tools, such as a shower bench, handrails, or a long-handled reacher, to help you manage your first weeks at home. You may assist ensure a smooth operation and a quick recovery by preparing ahead of time.


What happens during joint replacement?

during Artificial joints (knee, hip)

Your procedure might take place in an outpatient facility or a hospital. The procedure used by your surgeon differs based on the type of surgery and the joint that has to be replaced. You will be sedated shortly before your treatment. This assures that you will not experience discomfort during the arthroplasty procedure.

Incisions (cuts) are made by your surgeon, and the injured joint is removed. The joint is then replaced with an artificial joint. They seal the wounds with stitches, staples, or surgical glue. Your provider applies a bandage on the joint. A brace or sling may also be required.

Some joint replacement treatments can be performed by surgeons utilizing minimally invasive methods. These methods need fewer incisions and specialized instruments. Minimally invasive treatments may need shorter recovery time than standard procedures. Your surgeon will advise you on the best technique for you.


What happens after Arthroplasty?

In the hospital


You will be brought to the recovery room for observation following the procedure. You will be transported to your hospital room after your blood pressure, pulse, and respiration are steady and you are aware. Arthroplasty normally necessitates a few days in the hospital.

Following surgery, it is critical to begin moving the new joint. Soon after your surgery, a physical therapist will meet with you to create an activity rehabilitation program for you. Your discomfort will be managed with medication, allowing you to engage in the workout program. You will be given an exercise plan to follow both in and out of the hospital.

You will be sent home or to a rehabilitation facility. In either scenario, your healthcare professional will make arrangements for you to continue receiving physical therapy until you rebuild muscular strength and range of motion.


At home

When you go home, make sure to keep the surgery area clean and dry. Bathing instructions will be provided by your healthcare practitioner. During a subsequent appointment visit, the sutures or surgical staples will be removed.

Take a pain reliever as directed by your healthcare provider. Aspirin and other pain relievers may raise the risk of bleeding. Take just the medications that have been prescribed to you.

Notify your healthcare provider to report any of the following:

  • Fever or chills
  • Redness, swelling, bleeding, or other drainage from the incision site
  • Increased pain around the incision site
  • Numbness and/or tingling of the affected extremity

Unless otherwise directed by your healthcare practitioner, you may resume your usual diet. You should not drive until your doctor has cleared you to do so. Other limits on activities may apply. Making specific changes to your house may aid in your recuperation. These changes include the following:

  • Proper handrails along all stairs
  • Safety handrails in the shower or bath
  • Shower bench or chair
  • Raised toilet seat
  • Stable chair with firm seat cushion and firm back with two arms. This will allow your knees to be positioned lower than your hips
  • Long-handled sponge and shower hose
  • Dressing stick
  • Sock aid
  • Long-handled shoe horn
  • Reaching stick to grab objects
  • Firm pillows to raise the hips above the knees when sitting
  • Removing loose carpets and electrical cords that may cause you to trip

Depending on your specific scenario, your healthcare professional may provide you with extra or other instructions following the treatment.



Recovery after Artificial joint replacement

Depending on the operation, you may be able to go home the same day, or you may need to stay in the hospital for a day or two. Discuss rehabilitation plans with your physician. You will need to arrange for someone to drive you home. You may also require assistance walking about or conducting duties like as washing or showering.

You will have some discomfort following surgery. In the days after your surgery, you should:

  • Avoid physical activity. Take your time recovering after surgery. Your doctor may advise you to apply ice or a cold compress to the new joint for around 20 minutes at a time.
  • Follow your physical therapy and home exercise regimen exactly as directed. It is critical to follow the recommendations provided by your physician. They will not only aid in your recuperation and restoration of function, but will also safeguard the new joint.
  • Elevate. Depending on the joint you had replaced, your physician may advise you to keep it elevated while you sleep. If you have a knee replacement, for example, rest your foot on a stool or chair rather than the floor.
  • Keep your incisions clean and covered. Carefully follow your provider's incision care recommendations. After your procedure, ask your practitioner when you can remove the dressing, wash, or bathe.
  • Take pain medication. Your doctor may advise you to use nonsteroidal anti-inflammatory medicines (NSAIDs) or prescription pain relievers. When using pain medication, always follow your doctor's directions. You may also require medication to minimize edema or avoid blood clots.


What are the risks of joint replacement?

risks of joint replacement

As with any surgery, there is a risk of complications from arthroplasty. The risks include:

  • Blood clots.
  • Infection.
  • Injury or damage to nerves around the replaced joint.
  • Joint stiffness, weakness or instability that may lead to a fracture.
  • Problems with the new joint, including dislocation.
  • If you have certain medical problems, you are at a higher risk of complications with arthroplasty. Inform your surgeon if you have diabetes, hemophilia, or an autoimmune condition such as lupus. These problems can make joint replacement recovery more challenging.


When can I go back to my usual activities after joint replacement?

usual activities

Everyone's recovery following joint replacement is unique. Inquire with your physician about when you will be able to resume your favorite activities following your arthroplasty. It's a good idea to discuss this before surgery so you know what activities are suitable after a full recovery.

Your recovery time will depend on several factors, including:

  • Activity level and lifestyle.
  • Age.
  • Joint that was replaced.
  • Other health conditions or orthopedic problems.
  • Whether you had a total joint replacement or a partial joint replacement.

A physical therapy regimen can help most patients recover faster. PT helps to strengthen the muscles surrounding the replacement joint. This allows them to provide greater support for the joint. These workouts also improve flexibility and mobility.



artificial joint replacement

Artificial joint replacement can assist those who suffer from joint pain and stiffness return to their favorite hobbies. Following a joint replacement, many patients regain mobility and lead a more active lifestyle. However, everyone recovers differently, and you may need to modify your activities to preserve your new joint. Before surgery, have an open discussion with your provider about what to expect afterward. It is critical to set realistic goals.