Endoprosthesis of the hip and knee

Arthrosis is a chronic, progressive, degenerative decay of the synovial joints, most commonly hips and knees, because they are the most affected during their lifetime. This highlighted aging process of the joints is manifested by the dysfunction of the cartilage layer of the joint due to the genetically conditioned cartilage quality (primary arthrosis) or increased load, deformity, trauma, metabolic disorders (secondary arthrosis). Cutting of the joint cracks leads to the approaching of the joint surfaces and the consequent looseness of the joint capsule, the increase in micromovements and friction in the wrist. There are three stages of aggravation of the knee arthrosis.

Clinically this is manifested as a strong pain, stiffness and deformation of the joint. In the initial stage, physical therapy shows results, but if the disorders are worsening then it gets to surgical replacement of the joint – the implantation of the hip or knee endoprosthesis. Implantation of total endoprosthesis allows immediate full support, the release of the walking cane after 3 months, returning to full activities after 3-6 months, except for contact and difficult sports.

What is arthroplasty?
Artroplasty is a surgical procedure for implanting the artificial joint. Artificial joints are called endoprosthesis, they are inserted instead of a sick or damaged joint.

How is the knee built?
A knee is an ankle between the femur and the tibia (the tibia of the lower leg), and the kneecap (patella). The ends of the bones in the joint are wrapped with a cartilage. The joint cartilage is a smooth and elastic tissue that protects the surface of the bone from damage, absorbs the load and allows smooth gliding of the bones one of the another reducing the friction and pressure between their edges during movement. The whole joint is wrapped with elastic tissue called a joint capsule. The inner layer of the joint capsule is called the synovial membrane that secretes synovial fluid in the joint. Synovial fluid lubricates the joint and feeds the cartilage.

Meniscuses are connective-cartilage tissues that are found inside knees, they have half-moon form (letter C). There are two meniscuses, medial and lateral meniscus, which are located in the knee placed on the articular cartilage between femur, tibia and patella. Meniscuses serve as shock absorbers in the knee, absorb load during movement and increase knee stability, they also protect the joint cartilage from friction during movement.

Why is endoprosthesis embedded?
Artificial joint of the knee is built in when the joint cartilage collapses, which causes the bones in the joint to rub against one another during movement. The consequence is deformation and damage of their regions, and the pain and difficulty of the movement. When the joint cartilage is “used up” (the joint becomes stiff, and the movements are extremely painful), the artificial joint is inserted to prevent further damage to the ends of the bones. Endoprosthesis is inserted to relieve pain and restore movement in the joint, or to replace thefunction of damaged joint, which improves quality and makes life easier for the patient.

How does the implantation of knee endoprosthesis look like?
It is more of a type of endoprosthesis (the main ones are cemented or without cement). The type that is implanted in a particular patient depends on their age, daily activities, cause of damage, deformation of the knees, bone mass, etc. Knee joint endoprosthesis consists of three main parts: tibial, femoral and patella component. The femoral component is usually made of metal, while the tibial and patella component are made of metal and a plastic part.

The plastic part takes the role of meniscus and cartilage, protecting the metal surface of the endoprosthesis. During the operation, damaged parts of the femur, tibia and patella are removed. Then, parts of the endoprostheses are inserted into their place, which then get connected and reinforced making the new artificial joint.

How does rehabilitation look like after surgery?
Patients stay in the hospital 2 to 4 days after surgery. It is necessary to use mobility aids (walkers, crutches…). After surgery, it is necessary to access the rehabilitation program as soon as possible. Therapy sometimes starts at the pool. By exercising in the pool the joint gets less stressed, and movements and exercises are easier to perform in the water. This is followed by an individualized rehabilitation program. The goal is to regain the strength and stability of the knee joint. It starts with methods for reducing pain and inflammation (ice, resting, anti-inflammatory drugs).

At the beginning of the program, passive stretching attempts to regain the range of movement (led by the therapist), isometric exercises (static exercise) for the strength of the muscles of front side of the quadriceps are added, but also for the muscles of hips and thighs. Dynamic exercises of strength and power are also recommended in progression. The therapy uses kinesitherapy exercises of balance and stability, strength, and proprioceptive exercises.
In progression are also used exercises that simulate the daily activities of the patient.

The main goal of the rehabilitation program is to return the strength and ability to walk, and to be able to perform all other activities without risk, as well as achieving the best possible stability, capacity and durability of the artificial joint.

The hip is a mobile joint, it is one of the largest and the most important joints, since it has an inevitable role in the development and preservation of the correct architecture of the entire locomotor system, that is, the body’s statics and symmetry.

Hip surgery
It is therefore understandable that the prevention of hip injury occupies a special place from the aspect of preserving the health and normal mobility of each individual, but also from the health and economic aspect.

Hip fracture – Hip operation
The concept of hip fracture involves various types of fractures of this joint, but usually it refers to fractures of the upper part of the femur bone near the compound with pelvic bone. Depending on the place, the type and severity of the fracture symptoms can be different, but in any case they cause pain of different intensity and limitation, or the inability to move the injured part.
Treatment of hip fracture, depending on the clinical picture, may be conservative or surgical.

Conservative methods include long-term immobilization, that is resting, with the use of drugs such as analgesics and corticosteroids, but this therapeutic approach is often insufficient and reserved for a small number of patients with minor fractures.
Most often the surgical intervention (hip operation) is necessary, and in some cases it is also necessary to install an artificial hip.

Endoprosthesis of the hip (artificial hip)
Operation of the hip – The most common reason for the implantation of total hip joint endoprosthesis is hip arthrosis or fractures (whether fresh or obsolete).

What kind of arthrosis are there?
With primary arthrosis is not known the cause of arthrosis, while secondary arthrosis occurs because of rheumatic or similar illness, as well as post traumatic conditions or earlier operations.
Operation of the hip with the installation of total endoprosthesis, or artificial hip (artificial hip), is one of the most common and most successful operations in orthopedics. Modern technologies for the development of hip prosthesis, high-quality biomaterials and advanced operating technique allow rapid post-operative recovery and complete pain disappearance that was present before surgery.

Types of hip replacements
When selecting a type of prosthesis, each patient is individually treated and many factors are taken into account. Some of them are patient’s age, the degree of damage of the hip joint, the anatomical characteristics, the expected degree of physical activity, the initial illness or previous intervention. Cementless hip replacement is implanted in younger patients with the necessary preserved bone structure that will grow in the prosthesis and achieve firmness. This type of prosthesis is also implanted in most of our patients.

With elderly patients and patients with inadequate bone quality (usually osteoporosis), we install a cement replacement. The patient’s age is only one of the factors influencing on the decision fn the type of implant replacement.

Revision of total hip replacement (hip reoperation)
The revision of total hip replacement (hip reoperation) is a standard procedure today, both in our institution and in the world. With the increase of the number of total hip replacements, there are more and more hip revisions (hip reoperations).

In time, there are small movements in the bone and the wasting of the prosthesis material, which causes pain during moving, that can be increased over time. For these reasons, it is necessary to do an orthopedic examination once a year and to make an X-ray footage of the hip replacement.

Besides repairing the fracture, injuries and implantation of the prosthesis, there are the so-called biological procedures and interventions where the affected joint function is brought into functional condition with regenerative therapies (PRP and ACP) or biological operations (stem cells) without the artificial hip, this is mostly with younger people.

How to perform hip surgery
After preoperative preparation and decision on which type of anesthesia is the most adequate (block anesthesia, spinal or general anesthesia), the operation is approached. It is important to note that damage to the musculature is minimal, which enables rapid rehabilitation with the preserved function of the hip muscles.


Word of doctor

PhD Aleksandar Jakovljević

Orthopedics includes the treatment of a wide range of orthopedic disorders and sports injuries. The S.TETIK Clinic is one of the first in the region where you can undergo the most modern methods and techniques.

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