Joint replacements are artificial joints that remain permanently in the body. They are used when wear and tear (osteoarthritis) or injuries severely limit mobility and conservative treatments have been exhausted. Hip and knee joints are most commonly replaced; shoulder and ankle joints are replaced less frequently. The procedure falls under the field of orthopedics and trauma surgery and is performed by specialized teams.
A joint replacement is a permanent joint prosthesis (primarily for the hip and knee) that is implanted in cases of advanced osteoarthritis, injuries, or deformities when conservative treatments have been exhausted. Modern implants made of metal alloys, ceramics, and polyethylene are cemented, cementless, or hybrid in design and, in combination with structured rehabilitation, enable the rapid restoration of mobility and daily functioning. Risks such as infection, loosening, or thrombosis are rare; regular follow-up examinations ensure long-term function.
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Physicians who hold this seal are affiliated with medical facilities that are certified by endocert as an Endoprosthetics Center (EPZ) or as a Maximum Care Endoprosthetics Center (EPZmax) and have thus demonstrated through an audit that they meet the established requirements. Recertification is required every three years.
The criteria, requirements, and differences between EPZ and EPZmax can be found here.
The use of an endoprosthesis—that is, an artificial joint—is indispensable in modern medicine. In Germany alone, approximately 233,000 hip endoprostheses and 187,000 knee endoprostheses are implanted annually (source).
Thanks to medical advances, it is now possible to replace nearly any joint in the human body. Improved implants, less invasive surgical techniques, and longer-lasting prostheses lead to excellent long-term outcomes.
The most common reason for joint replacement is osteoarthritis. In addition, arthritis, fractures, tumors, necrosis, or severe deformities may also necessitate surgery. Younger patients are also increasingly requiring joint replacements, for example, following injuries or due to congenital joint disorders.
The most important reasons are listed below:
An implant becomes necessary when conservative treatments (medication, physical therapy, injections) no longer provide sufficient relief.
The video shows the destruction of the joint surfaces in knee osteoarthritis:
Arthritis is an inflammatory disease of the joints. It can be acute or chronic and often leads to pain, swelling, and progressive damage to the joint surfaces.
One specific form is rheumatoid arthritis (chronic polyarthritis). This is an autoimmune disease that usually affects several joints at the same time. The joints most commonly affected are:
If the inflammation persists for a long time, it can destroy the cartilage and contribute to osteoarthritis.
In severe cases that do not respond adequately to medication or physical therapy, joint replacement with artificial prostheses is necessary to relieve pain and restore mobility.
Malalignments of the extremities can cause uneven distribution of stress on the joints. Over time, this leads to osteoarthritis-like signs of wear and tear and increased joint degeneration.
Typical examples include:
Such misalignments can accelerate the development of secondary osteoarthritis. If conservative treatments are insufficient and mobility is severely limited, hip or knee replacement with an endoprosthesis may be necessary.
Necrosis refers to the death of cells or tissue in a living organism. When this affects bone, it is referred to as bone necrosis.
A typical example is femoral head necrosis (hip head necrosis). In this condition, part of the bony head of the femur dies—usually due to impaired blood flow. Causes may include:
If left untreated, necrosis leads to collapse of the hip joint and severe pain. In such cases, a hip replacement is often necessary to restore joint function.
Severe fractures or trauma in the joint area can be so severe that reconstruction is not possible. In such cases, an endoprosthesis is implanted to restore mobility.
A typical example is a femoral neck fracture—a break in the neck of the femur immediately adjacent to the hip joint. It commonly occurs after a fall onto the side, particularly in older adults with osteoporosis.
Shoulder injuries (e.g., following falls or severe blows) can also lead to deformities that require an artificial replacement.
Bone tumors or metastases (secondary tumors) in the area of bones near a joint can also damage the joint so severely that a replacement becomes necessary.
In these cases, an endoprosthesis helps restore bone stability, relieve pain, and ensure mobility—often as part of concomitant tumor treatment.
A dislocation refers to the displacement or popping out of a joint. Commonly affected areas include:
A single episode can usually be treated conservatively. However, if dislocations occur repeatedly and lead to permanent instability, a joint replacement may be necessary. The replacement restores stability, relieves pain, and improves mobility.
In certain conditions or cases of severe injury, arthrodesis—that is, surgical joint fusion—may be necessary. In this procedure, the affected joint is permanently fused to relieve pain.
In the long term, however, the lack of mobility often leads to overuse of neighboring joints and, consequently, to premature joint wear (osteoarthritis).
In such cases, the implantation of a joint replacement may be necessary later on to restore function to the affected area and improve mobility.
For a joint replacement to remain in the body permanently, it must meet high standards. A modern implant should:
Today, the following materials are primarily used and are undergoing continuous development:
Despite the high quality of these implants, wear or loosening can occur over the years. That is why regular follow-up examinations are important to detect changes in a timely manner and ensure the proper functioning of the artificial joint.
Endoprostheses can be fixed in the bone in various ways:
The method used depends on:
Using the appropriate fixation method can extend the lifespan of the endoprosthesis and ensure long-term mobility.
The implantation of a joint replacement is a surgical procedure performed under general anesthesia or regional anesthesia (spinal anesthesia). Depending on the joint and technique, the surgery typically lasts 1 to 2 hours.
Prior to the procedure, the following are performed:
The actual procedure involves:
Making the joint incision (traditional or minimally invasive)
Removal of the damaged joint surfaces and cartilage remnants
Preparation of the bone to accommodate the implant
Insertion of the endoprosthesis—cemented, cementless, or as a hybrid prosthesis
Checking for proper fit, stability, and mobility
Closure of the wound; insertion of a drain if necessary
Rehabilitation begins early after surgery:
Consistent follow-up care is crucial to prevent complications and extend the lifespan of the endoprosthesis.
The hip joint is the joint most commonly treated with a hip replacement worldwide. A hip prosthesis is implanted in cases of:
The prosthesis can be anchored:
A hip replacement significantly reduces pain and improves range of motion and mobility in daily life. Modern implants have an excellent lifespan of 15 to 20 years, and often even longer.
An endoprosthesis can also be implanted in the ankle joint. This is particularly beneficial in cases of severe osteoarthritis or following accidents.
An artificial knee joint is implanted in cases of advanced knee osteoarthritis or following severe fractures. The goal is to reduce pain and restore range of motion and mobility.
Other reasons for knee replacement include misalignments (e.g., bowlegs, knock-knees), old injuries, or chronic inflammation.
When the cartilage layers are completely worn away and bone rubs against bone, severe pain results. In such cases, a knee replacement becomes necessary.
Although the vast majority of patients benefit from a knee replacement, complications can occur.
Important: Regular follow-up examinations (clinical and X-ray) are crucial for early detection of problems.
The implantation of a hip replacement is performed under general or spinal anesthesia and usually takes 45 to 120 minutes. Whenever possible, modern clinics use minimally invasive procedures that preserve muscles and tissues.
Skin incision; muscles carefully moved aside
Removal of the damaged femoral head
Preparation of the acetabulum
Insertion of the hip prosthesis (cemented, cementless, or hybrid)
Checking for mobility and stability
Closure of the wound
Anterior approach, patella moved to the side
Removal of worn cartilage and bone
Preparation of the bone using templates or digital systems
Insertion of the knee prosthesis
Checking fit, stability, and mobility
Wound closure
The success of a knee replacement depends largely on postoperative care.
Consistent follow-up care ensures that patients with a joint replacement can once again participate actively and pain-free in everyday life.
Minimally invasive joint replacement is becoming increasingly important. It is used for both the hip and knee joints and is considered a modern surgical technique that preserves muscle and bone tissue.
While the media often emphasizes the small incision, the real advantage lies in the reduced damage to muscles, tendons, and the joint capsule. This allows for faster postoperative rehabilitation and improved mobility.
Conclusion: Patients benefit most when the surgery is performed by an experienced specialist.
A minimally invasive technique can also be used for total knee replacement. The goal is to minimize damage to muscles, tendons, and bones.
For the knee joint, the advantages of minimally invasive procedures are therefore less pronounced than for the hip. Precise positioning of the implant is crucial, as it significantly determines the lifespan and function of the joint replacement.
In the video, you can see the principle behind total knee replacement:
Minimally invasive implantation of knee joint prostheses can, in theory, offer similar advantages to those seen with hip joint replacements when compared to conventionally implanted prostheses.
However, minimizing muscle damage at the knee joint depends not only on gentle surgical techniques and specialized approaches, but also on how long the tourniquet is in place and how long blood flow to the leg is interrupted as a result, which presumably causes greater damage to the muscles than gentle surgery can compensate for. This must be taken into account.
Most scientific studies on this topic show no differences over a 6-month period between conventional approaches and minimally invasive approaches of any kind.
In knee arthroplasty, it has been shown that the risk of misplacement of prosthetic components is greater with small access pathways and limited visibility than in hip arthroplasty. Therefore, this must be weighed particularly carefully.
Not every injury to the hip or knee can be treated using a minimally invasive approach.
Minimally invasive surgeries require a high degree of routine. Surgeons should perform many of these procedures each year to ensure the necessary level of confidence.
In Germany, over 350,000 artificial hip and knee joints are implanted each year. Patients benefit when:
It is always crucial to have an experienced specialist who weighs the benefits and risks and selects the safest procedure for the patient.
Every physician listed in the Leading Medicine Guide has attained the highest level of training and certification within their respective medical specialty society. Furthermore, we contacted this physician based, among other factors, on their case volume (surgeries, treatments, and therapies), which we determined by cross-referencing various publicly available sources. Following discussions with the selected physicians and the directors of the medical facilities, as well as a subsequent internal review, they were admitted to the Leading Medicine Guide.
The quality assurance of the Leading Medicine Guide is further ensured by 8 admission criteria. Each member must meet at least 6 of them:
