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3D print knee replacement


How Does a 3D Printed Knee Replacement Work?

Medical professionals now use 3D printing to create titanium jaws, hearing aids, limbs, organs, and in the production of customized knee replacements.

Invented by Chuck Hull back in 1983, 3D printing is the process of using a printer to transform a digital three-dimensional model into a physical object. Learn how a 3D printed knee replacement works and how Conformis can transform a digital three-dimensional model into a physical object.

Additive Manufacturing

There are two basic types of manufacturing: subtractive and additive. In subtractive manufacturing, manufacturers start with a large block of material then shave away, or subtract, what they do not need.

Additive manufacturing is the direct opposite of subtractive manufacturing – manufacturers add layer upon layer of material to achieve the desired effect. 3D printing is additive manufacturing, as special print heads lay down layers of various materials to create products.

While subtractive processes have been the mainstay of manufacturing for decades and are still the norm, 3D printing and other additive manufacturing processes have distinct benefits. Subtractive manufacturing requires stripping away material, creating a great amount of waste, to make each component of a piece then assembling all the components to create the finished product. 3D printing allows manufacturers to create very complex products containing multiple materials with very little waste.

A 3D printed knee replacement consists of:

  • Nylon
  • ABS plastic
  • Resin
  • Stainless steel
  • Gold and silver
  • Titanium
  • Ceramic
  • Gypsum

The ability to use a variety of materials allows manufacturers to make incredibly strong and complex items. Many of the materials, especially titanium, are suitable for use in medical devices because of their strength and lower risk for rejection. By building objects up in layers, 3D printing can produce objects that are hollow or extremely intricate.

3D Printed Knee Replacement: What We Print and Why

At Conformis, we use the latest in 3D printing (additive manufacturing) technology to create one set of surgical instrumentation, called iJigs, per patient. These instruments allow your surgeon to ensure that your customized implant is positioned correctly.

To create the iJigs, a robotic arm deposits a layer of powdered nylon onto a tray. A laser then outlines each patient-specific shape, fusing the powder into solid shapes. This process is repeated many times, until the layers have built up and the final shapes of the instruments are created. When the jigs are removed from the 3D printer, they are consolidated in one rectangular package. The individual pieces are then removed and sterilized before being packaged for shipment to your surgeon. We also use 3D printing to create the wax molds the metal implants are cast in.

What’s the benefit? Since each of our implants is customized to the patient, this process allows us to quickly build all the parts required for a knee replacement in a relatively short time. This also allows us to make updates to our implants more regularly since we don’t have existing inventory to use up first.

Click here to learn more about our technology and customization processes.

Knee Replacement Dallas, 3D Printed Custom Knee Implants-Richard Buch, M.D.

Dr. Buch explains why he prefers custom knee implants for knee replacement

When considering knee replacement would you want your natural knee recreated or replaced? 

The majority of knee replacement in the United States is done with off the shelf implants. Off the shelf implants are mass produced with fixed angles and come in a variety of sizes to cover the majority of all patient's joint size. This traditional approach to knee replacement requires your surgeon to pick the implant that is the closest size to your natural knee and then work to make your knee fit the implant. When Dr. Buch utilizes the 3D technology for knee surgery each patients unique anatomy is imaged and then utilize to create a custom implant to exactly fit your natural knee. Just like our DNA, every knee joint is different as we all have slight nueances that can not be accounted for with traditional off the shelf implants. We have learned through many  studies examing knee replacement data that 20-25% of all traditional knee replacment patients have some issue with their new knee. The most common feedback in the 20-25% of traditional knee replacement patients is it just does not feel like my natural knee. 

What are the potential benefits of utilizing custom made knee implants versus off the shelf implants?

  • Reduced operating time
  • Reduced anesthesia time
  • Quicker recovery
  • Shorter length of hospital stay
  • More natural feeling knee
  • Preservation of your knee's natural shape, joint line, and kinematics
  • Less blood loss
  • Less bone removal 
  • Improved fit of your implant
  • Reduced risk of infection (reduced operating time & use of pre-steralized one time use patient specific instrumentation)

From image to implant. Learn how custom knee implants are made:

Frequently Asked Questions Regarding 3D Knee Replacement:


Why does Dr. Buch prefer customized knee implants versus off the shelf implants for his patients?The primary reason is everyone's knee anatomy is different. Most knees look the same however the bones and angles that make your natural knee are all slightly different. If we create an implant utilizing the exact anatomy of your natural knee you should have a more natural feeling knee. With traditional off the shelf knee implants the surgeon has to select the implants from pre determined sizes that most closely fit your knee during surgery. With custom made knee implants for each patient we know the implant we utilize will be a precise fit prior to surgery.  

Why do I need a CT scan for custom knee implants and what does it allow you to see?

A CT scan or computed tomography scan is an advanced medical imaging technique used to non-invasively acquire detailed images of various anatomy within the body for diagnostic purposes. This CT scan allows us to capture the specific anatomy and variations in each knee joint to create a custom implant. This information is then sent to an engineer and uploaded to proprietary software that creates a digitial image that will serve as the blueprint for each custom knee implant. This 3D model is then sent to a 3D printer that develops the mold and custom instrumentation for each surgery. 


How does the recovery differ with a customized knee implant?Recovery after knee replacement with off the shelf implants typically took three months. Knee replacement recovery today is quite different as there have been significant advancements in anesthesia, pain control, surgical techniques, and implant design. These factors have significantly reduced the recovery time following knee replacement as the majority of patients recover within three to six weeks. Another significant shift in the recovery of knee replacement patients is the hospital stay following knee replacement. Historically, knee replacement with off the shelf implants patients would stay in the hospital three to seven days. Today, knee replacement with customized implants ninety-five percent of our patients go home in one to two days. These advancements have also allowed the appropriate candidates to have knee replacement on an outpatient basis where patients will go home in hours following surgery.


Are there limitations on who is a candidate for knee replacement with custom implants?Anybody with severe arthritis of the knee that has failed conservative treatment modalities is a candidate for knee replacement with custom implants. There are some minor limitations to utilizing a custom knee implant, if you have severe deformity of the knee joint we may not be able to make a knee to your anatomy. If you have a lot of bone loss, you have had significant trauma, or if you have a lot of hardware in the knee you may not be able to have a customized knee. 


How does customized knee replacement technology allow Dr. Buch to achieve natural mechanical ailgnment and how is this beneficial for patient outcomes?By utilizing data obtained during your CT scan we know the knee is going to be a precise match resulting in a better fit and alignment. This will result in a better balanced knee which increases the range of motion and results in a more natural knee.   During knee replacement mechanical ailgnment is important because most people are born with their leg in a valgus alignment. As we age this can worsen moving toward a more neutral position or it can change to varus alignment which is the most common. A mistake that was historically made in knee replacement is that most patients walk around for 20 plus years with a varus ailgment and then surgeons would put their new knee in valgus alignment to represent the way their knee joint was before aging and wear and tear caused this change. It is best to put the knee implant in the position you are used to walking in or a neutral position. Patients will tolerate this ailgment better when they walk as it will feel like their own knee. A surgeon can do a great job with the surgical process of replacing your knee but if the ailgnment is off or changed it can result in pain or an unnatrual feeling knee.


What are the differences in patient satisfaction with a custom knee implant versus an off the shelf impant?We conducted a study on patients who received bilateral (both knees) knee replacement. For patients to be in the study they had to have a knee replacement with an off the shelf implant and be a current candidate for knee replacement on the opposite side with a custom made knee implant. Every patient in the study reported higher satisfaction scores with the customized knee implant, they liked it better, reported they recovered quicker, and reported the custom knee implant felt better then their off the self implant.  

What is the difference between a 3D knee replacement with custom implant versus a robotic knee replacement?First, there is a significant difference between the two. The potential issue with robotic knee replacement is you have to input data into the computer, dial in the robot, and use an off the shelf implant to match your knee to the implant. Some surgeons say the robot helps them put in the implant better, this may be true but the implant utilizes for robotic knee replacement is still not a perfect match to your knee like a custom made implant. Custom made implants are designed for your knee and your knee only resulting in less surgery then robotic surgery. Robotic surgery also requires additional incisions to make pin holes for the navigation component of the robot. The custom made implant system made by Conformis is a much simpler, straighforward system that allows surgeons to produce consistant results. 

How do I find out more information about customized knee implants and the company that produces them? We receive calls from across the United States about Conformis custom made knee implants from presentations Dr. Buch has given or patients find this website. The best thing to do for more information on custom made implants, Conformis, or the process of knee replacement is to contact our office at 469-443-0939 to schedule an appointment with Dr. Buch. Dr. Buch has been an early adopter of this technology and had first hand seen the benfit this technology provides to patients. Dr. Buch will explain knee replacement with custom implants in detail and you will have all the time you need to ask questions. If you are in a different state or unable to travel to our office locations near Dallas, Texas we would be happy to help make a recommendation on a good surgeon who utilizes this technology near you. Another option is to visit the Conformis website here to obtain additional information. 

Dr. Buch peformed bilateral 3D Knee Replacement on Don. Watch the video below to learn more about Don's experience with custom made implants:

Dr. Buch has been featured in numerous articles and interviews for his expertise and outcomes with 3D knee replacement:

Beckers ASC Review: Outpatient Total Knee Replacement: Critical factors enabling successful total knee replacement procedures in ASCs.  

Living Well Magazine: The Perfect Fit, Customizing Your Knee Replacement Surgery

Surgeon Experience Interview with Richard Buch, M.D.: Knee Replacement Instability

Richard Buch, M.D., Clinical Investegator: Clinical Study Demonstrates Conformis Customized Knee Implants Provide Superior Outcomes & Potential for Economic Savings

3D Printer Gives Patient New Knees, Ability to Run 


About Richard Buch, M.D.

Richard Buch, M.D. is the founder of The Dallas Limb Restoration which has become a national referral center for complex pathologies of the knee, shoulder, and hip. As a leader in his field and featured expert at countless national and international meetings Dr. Buch offers patients innovate technologies and treatment solutions for pain, injury, and degenerative conditions. Dr. Buch has over 25 years experience performing knee replacements and has done over 13,500 knee, hip, and shoulder surgeries. To schedule an appointment with Dr. Buch click here or call 469-443-0939. 

Richard G. Buch, MD


Board-Certified Fellowship Trained Orthopedic Surgeon & Regenerative Medicine Specialist

New material allows 3D printing of knee cartilage implants

3DNews Technologies and IT market. News printers, print servers, scanners, copiers... The new material allows you to print knee...

The most interesting in the reviews

05/02/2017 [14:13], Konstantin Khodakovsky

Scientists from the American Duke University have created a material that mimics human cartilage and can eventually be used by surgeons for 3D printing of implants to replace damaged parts of the knee joint, individually shaped to the anatomy of each patient. nine0007

Human knees have a pair of menisci, crescent-shaped cartilages that act as shock absorbers. But over years of stress, these important parts of the joint can wear out, or be severely damaged by one wrong move while playing football or tennis. The result is pain and an increased risk of developing arthritis.

Scientists claim their hydrogel-based material is the first to match the strength and elasticity of human cartilage while remaining stable inside the body and allowing it to be used in the 3D printing process. To prove their point, the researchers used a $300 3D printer to print custom menisci for a plastic model of the knee. nine0007

Duke University Associate Professor of Chemistry and Published Author Benjamin Wiley notes: “We have now made it possible for everyone to print implants that are very similar in medical properties to human cartilage in a fairly simple and relatively inexpensive way.” .

It is worth noting that this is indeed an important achievement. The fact is that torn or damaged menisci are very capricious to the process of self-healing. Surgeons often have to partially or completely remove them, and existing implants either do not match the strength and elasticity of the original, or have poor biocompatibility and prevent the healing of the damaged area. nine0007

Recently, materials called hydrogels, which are very similar in molecular structure to cartilage and are biologically compatible, are increasingly being used as replacements for cartilage. However, researchers have not been able to create a hydrogel that would match the characteristics of human cartilage and be effective in 3D printing. The latter is very important, because the menisci have a complex shape and vary greatly from person to person. 3D printing will allow you to create customized implants that will take root better. nine0007

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Titanium elbow. A 3D-printed joint was delivered to a Petersburger | HEALTH

Evgenia Agapova

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Weekly "Arguments and Facts" No. 47. Arguments and Facts - St. Petersburg 24/11/2021

The endoprosthesis is able to replace the affected areas of the femur. Northwest Technology Transfer Center

In St. Petersburg, scientists, together with practicing surgeons, have developed a unique endoprosthesis to replace part of the femur and knee joint. The product is made taking into account the anatomical features of the patient from a biocompatible material, has high strength and - importantly - durability.

Someone else's as one's own

The new endoprosthesis is an all-metal non-separable implant, which is used to replace the affected areas of the femur and knee joint. It has increased strength and durability due to the presence of a minimum number of connecting elements in it. nine0007

The concept of the product was created by the staff of the St. Petersburg NMITs TO them. R. R. Vreden and finalized at the CML AT Medical engineering center.

Engineers optimized the shape of the endoprosthesis, determined the places of use and the volume of cellular structures in the implant (they contribute to better osseointegration of the product in the patient's tissue), achieved a halving of the cost of production, while maintaining the characteristics.

“The product was modeled based on the patient's computed tomography images. This made it possible to design the prosthesis taking into account the anatomical features of the patient. The implant was made using 3D printing from a biocompatible titanium alloy,” explains Head of CML AT Medical engineering center Yana Chekryzhova .

The endoprosthesis is “printed” not in St. Petersburg, but in Moscow, at a contract 3D printing factory. Such a model, according to the company, allows for a more rational distribution of the financial and labor resources of the team.

The prosthesis proved itself

The first operation using this development was carried out in the fall of 2020. The patient needed to replace a large defect in the femur.

“The use of the implant ensured the achievement of reliable fixation of the standard design of the articulating knee endoprosthesis. This allowed the patient to recover quickly, without changes in the standard rehabilitation program, ”comments Professor of the Department of Traumatology and Orthopedics, Head of Department No. R. R. Vreden Nikolay Kornilov .

Further, in the postoperative period, after three and six months, doctors conducted control studies that showed the success of the connection of the implant with the patient's bone. As a result, motor functions and the length of the operated limb were restored. It is now known that the patient has no complaints about the state of health and the product itself. The implant proved to be the best in terms of survival and operation. nine0007

NMITs TO them. R. R. Vredena has already performed more than 35 surgeries using customized printed implants. The only thing that is required for each new operation is to adapt the product to the patient, taking into account his anatomical features.

“At first glance it may seem strange, but we hope for a high probability of the emergence of new domestic players in the market of individual implants. Our example shows that Russian developments are not inferior to foreign ones in terms of price-quality ratio, and even surpass them in the speed of order fulfillment,” says Yana Chekryzhova. “The more domestic players there are on the medical devices market, the more patients will benefit – personalized prostheses will become more familiar and affordable, and their choice will become more diverse.” nine0007

However, the developers are confident that even with a similar overall concept, all products will still differ from each other. It is these differences that will determine the winner in the upcoming competition.

endoprosthesisdevelopmentsciencetechnology prosthesisfemoralknee jointorthopedicshealthprosthetics

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