In the world of prosthetics, choosing the right knee joint is a decision that can define your comfort, mobility, and overall quality of life. Whether you’re newly amputated or upgrading your current prosthetic, selecting between a hydraulic and mechanical knee joint is crucial—and not always straightforward. Each type comes with its unique advantages, challenges, and considerations based on your activity level, lifestyle, and personal preferences.
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At Credence Prosthetics India, we understand that no two amputees are the same. That’s why we’re committed to offering tailored prosthetic solutions, guiding each individual to find the right fit for their needs and goals. In this guide, we’ll dive deep into the differences between hydraulic and mechanical knee joints, helping you make an informed decision that leads to greater independence, confidence, and comfort.
Understanding the Basics: What Are Prosthetic Knee Joints?
A prosthetic knee joint is an artificial component that replaces the function of a biological knee for above-knee (transfemoral) amputees. It plays a key role in:
There are several types of prosthetic knee joints, but hydraulic and mechanical are among the most commonly recommended by prosthetists—especially for users seeking mobility beyond basic walking.
Mechanical Knee Joints: Simplicity and Reliability
Mechanical knee joints have been used for decades. They operate using physical components like springs, friction controls, and locking mechanisms to manage movement.
Types of Mechanical Knees Include:
Benefits of Mechanical Knee Joints:
Drawbacks of Mechanical Knees:
Who it’s best for:
Low- to moderate-activity users, the elderly, people living in rural areas, and those needing a low-maintenance solution.
Hydraulic Knee Joints: Adaptive and Advanced
Hydraulic prosthetic knees use fluid dynamics to control the speed and resistance of knee movement. The hydraulic fluid (usually oil) adjusts according to the user’s movement, providing dynamic control and a smoother gait.
Some advanced hydraulic knees also include microprocessor-controlled systems (MPKs) that analyze gait in real time and adjust resistance levels accordingly.
Benefits of Hydraulic Knee Joints:
Drawbacks of Hydraulic Knees:
Who it’s best for:
Active individuals, professionals, younger amputees, or anyone who desires a more natural gait and versatile movement.
Credence Prosthetics: Matching You with the Right Technology
At Credence Prosthetics India, we understand that the right knee joint isn’t about choosing what’s “best” in general—it’s about choosing what’s best for you.
We use a patient-first approach that considers:
By working with top global component suppliers and offering custom-fabricated prostheses, we ensure every user receives a solution that’s balanced in technology, affordability, and real-world performance.
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Head-to-Head Comparison: Hydraulic vs. Mechanical Knee Joints
Real-World Stories: Empowering Lives with Credence Prosthetics
Arjun’s Story: Confidence in Every Step
Arjun, a 30-year-old architect from Chennai, lost his leg in a motorcycle accident. As someone constantly on construction sites and moving around the city, he needed a knee joint that could keep up. Credence fitted him with a hydraulic microprocessor knee, and within months, Arjun was not only back to work—but thriving.
“I don’t even have to think about my steps anymore. The knee just flows with me. It’s like having my real leg back.”
— Arjun, Credence Client
Radha’s Story: Simplicity Wins
Radha, a 65-year-old homemaker from Coimbatore, lives a quiet life tending to her home and garden. She opted for a mechanical locking knee from Credence. It gave her stability, was easy to use, and required almost no maintenance.
“The team at Credence explained everything patiently. My knee joint is simple, and it works perfectly for my lifestyle.”
— Radha, Credence Client
Credence Prosthetics: Why Patients Trust Us
FAQs: Making Your Decision Easier
Q: Can I switch from a mechanical knee to a hydraulic one later?
A: Yes! Many users start with a mechanical joint and upgrade later. Credence ensures your prosthetic setup is adaptable for future upgrades.
Q: How long do prosthetic knees last?
A: Mechanical knees may last 3–5 years, while hydraulic joints can last longer with proper care. Credence provides servicing and spare parts for long-term performance.
For patients who have lost a leg, regaining mobility is a top priority. However, development of more true-to-nature prosthetic limbs and joints has come an amazingly long way from the often thought of peg leg and hook hand. Over the past several years, medical prosthetic technology has advanced drastically, allowing for patients to regain the normalcy in their life that they would not have had access to in the past.
Otto Bock Healthcare GmbH, Duderstadt, Germany, a company with 90 years of orthopedic experience, has developed a more natural-feeling prosthetic knee joint to not only allow more comfortable and natural ambulation, but also provide a long-lasting, durable solution so patients can spend less time at the orthopedic mechanic, and more time living life as usual.
Otto Bock has developed their 3R60 and 3R78 prosthetic knee joints with their patented “EBS,” or “Ergonomically Balanced Stride”, system, which allows for an individually adjustable stance, reducing the strain on the hips and spine of the wearer. Suitable for patients up to 275 pounds, higher than with many traditional prosthetics, the joint is able to be adapted to patient weight and activity for additional comfort and stability, especially on uneven terrain, and four modular connectors make it an appropriate prosthetic for various levels of injury. The joint system uses special engineered components and features to mimic the motion enabled by a biological knee joint, unlike monocentric, single-jointed traditional prosthetics. (See Figures 1a and b)
In the joint itself, needle and bronze bearings, as well as PTFE guide tape, were replaced with plastic components from igus®. These plastic components are extremely light, do not require external lubrication, and also possess very low coefficients of friction, with excellent wear-resistance. According to Otto Bock, these plastic components allowed for the further development of their EBS joint systems to where they are today. The EBS joint system is lightweight and shock absorbing, allowing for more comfortable walking, and is extremely low maintenance thanks to low-wear, media-resistant, and corrosion-free components, meaning fewer trips to the orthopedic mechanic. The plastic bearings used in the joint were selected for special characteristics specific to the demands in a prosthetic knee joint. There are bearings made of different varieties of plastic material, including iglide® Q, which was selected because it is extremely resilient under high loads and exceptionally shock absorbing, making it an excellent buffer for impact loads. The material is also resistant to many chemicals, including solvents, oils, and weak acids. The bearings also have a low moisture absorption rate, letting the user walk in all weather without increased friction. The shock absorbing qualities of the plastic material, coupled with swing phase hydraulics, act as a substitute for cartilage in a biological knee, cushioning the force of two to four times the patient’s body weight that occurs with each step.
In prosthetic knee joints that utilize metal bearing systems, dirt, dust, pet hair, and other common debris is attracted to the external lubrication, therefore impeding the friction surface which can lead the knee to seize up and the patient to stumble or fall. The specialized plastic bearings in the EBS system are self-lubricating, using microscopic particles of solid lubricant included throughout the plastic material. Without external bearing lubricant, dirt and debris from everyday wear is not attracted to the joint, and any dirt is simply embedded into the plastic material with no noticeable increase in friction.
Patients using the EBS prosthetic joint are able to walk more naturally and comfortably than those with traditional prosthetics. The EBS joint gives a higher ground clearance in the swing phase of a patient walking due to the polycentric nature of the system. Polycentric knees, with more than one axis of motion, are more stable than single axis systems, which are essentially a hinge. The polycentric system gives a much more “knee-like” feel, and with added hydraulic power in polycentric joints like the 3R60, patients are able to have more variability in the walking speed and function, but at a price.
Typically, polycentric knee joints are heavier and more expensive than single-axis joints, even more so with added weight and cost of added hydraulics. Otto Bock’s joint systems, however, have compensated for the added price and weight by substituting plastic components that are very light weight and low cost, too. At only 1.8 pounds, the joint offers a joint flexion angle of 175 degrees, limited only by shaft connections/forms or optional cosmetic cover. The mini hydraulic system utilizes piston rings with separately adjustable flexion and extension to control the behavior of the joint during the swing phase of the walking motion. A rubber bumper is compressed during stance phase flexion, generating the corresponding movement resistance, which is adjustable per patient requirements. The hydraulic components absorb subsequent stance phase extension. The five-axis polycentric design structure of the EBS joint allows for separation between the swing and stance phases. In the stance phase, flexion is made possible by interplay between the lower front axis as the joint’s center of rotation with the EBS’s pivoting mount and the posterior link of the polycentric structure. The EBS pivoting mount also visualizes the degree to which the EBS function is used.
Piston rings are applied in the mini hydraulic unit in the top and bottom pistons located in the pneumatic cylinders. The piston rings replaced PTFE guide tape, used to create bands. When producing the knee joints, each piece of PTFE tape, supplied as a large coil, had to be cut to the appropriate size for the particular joint, then packed and stored in strips, inevitably with some error in sizing. If the strip was too long, it had to be cut again. Cropping on the cutting edge could leave the band too short, keeping it from properly fitting into the driving band groove. Instead of the lengthy and error-prone process of sizing, cutting, and fitting the PTFE tape, the piston rings simply snap onto the piston, greatly reducing the production costs and lowering the total cost of the joint. When tested within Otto Bock EBS joints, barely any perceptible wear was reported on the piston rings, even under maximum stresses, and according to the company, increased the quality, functionality, and durability of their overall system.
This article was written by Ellen Rathburn, Technical Copywriter for igus, Inc. East Providence, RI. For more information on Otto Bock, visit http://info.hotims.com/-189 . For more information on igus, visit http://info.hotims.com/-163 .