Differences between cementless and cemented hip replacement

At the State Budgetary Institution "GKB im. F.I. Inozemtseva DZM" free of charge, under the compulsory medical insurance policy (CHI) they carry out complex surgical treatment - ENDOPROSTHETICS OF THE HIP JOINT

Hip pain is most often the result of osteoarthritis and can seriously affect your ability to lead a full and active life. Osteoarthritis of the hip joint is medically called coxarthrosis.

Hip replacement will help you get rid of pain and return to a full life. Over the past 20 years, thanks to the introduction of new materials and techniques into practice, the results of endoprosthetics operations have significantly improved.

Hip replacement is becoming more and more common as the world's population ages. Currently, hip replacement surgery is the most frequently performed in the world.

Hip replacement is a total or selective replacement of parts of the joint that are in direct contact with each other during movement.

Total hip replacement is a complete replacement of the head and neck of the femur and acetabulum with artificial ones.

ANATOMY OF THE HIP JOINT

The hip joint is spherical in structure, so movements in it are possible in many planes. The joint is formed by the acetabulum, forming a kind of deep bowl, and the head of the femur, which has the shape of a ball.

The head of the femur is connected to the main part (the diaphysis) by a short section of bone called the femoral neck. Strong and thick muscles and tendons surround the joint.

The surfaces of the acetabulum and the head of the femur are covered with articular cartilage. The thickness of articular cartilage is about half a centimeter in large joints. Articular cartilage is a tough, smooth material that covers the bones in the joint area. Articular cartilage allows the bones it covers to glide smoothly past each other without being damaged. The color of articular cartilage is white and shiny.

The joint is surrounded by a dense, waterproof capsule, inside which a special fluid is produced that lubricates the articulating surfaces. The bones in the joint are held together by dense ligaments and muscles. The design of the hip joint allows for extremely high mobility while maintaining satisfactory stability.

Powerful muscles around the joint allow us to move in an upright position for a long time, and also, if necessary, to accelerate when running and jumping. There are also important nerves and blood vessels around the joint.

Operation financing channels

Hip replacement is performed through two funding channels:

1. High-tech medical care (the so-called quota) is when the state buys an endoprosthesis specifically for a person. It is performed free of charge for the patient. To obtain a quota, you need to collect the necessary package of documents and stand in line at the health department at your place of residence. From the moment the protocol is drawn up, it usually takes six months to a year to provide high-tech assistance.
2. At the expense of personal funds - the patient in this case pays for the hip replacement surgery in Moscow or at his place of residence, conservative therapy and the cost of the endoprosthesis itself.

Your attending physician will provide more detailed information.

Endoprosthesis companies

In our practice, we use endoprostheses from world-famous companies, such as DePuy (Johnson & Johnson), Zimmer, Smith & Nephew, Stryker, Biomet, Aesculap (B. Braun) and others. Each of the components of the endoprosthesis from different companies has its own design features, differences in surgical technique, etc. The doctor will decide which brand and type of fixation is right for you after consultation.

What is needed for hip replacement at a clinic in Moscow?

1. Analyzes
2. Fresh x-rays in 2 projections.
3. Elastic bandage – 2 pcs. (minimum 3 meters).
4. Crutches. It is better to purchase axillary crutches; it is easier to move with them than with arm crutches. Walkers can be used for rehabilitation; they make it a little easier to move around.
5. Personal items – toothbrush, toothpaste, towel, change of clothes, slippers with backs.
6. Razor – 2 pieces.
7. Sick leave (if available). It is important to remember the correct name of your work; it is indicated on the sick leave certificate, and writing errors are unacceptable.

If your joint hurts, the pain interferes with your life, conservative treatment does not help, then you need hip replacement (replacing it with an artificial one). There is no need to endure and suffer, otherwise you can “neglect” it, the ligaments and muscles will get used to the vicious position and rehabilitation in the postoperative period will be difficult and often not complete.

WHEN MAY ENDOPROSTHETICS BE NEEDED?

The main indications for hip replacement are arthrosis of the hip joint (coxarthrosis), fracture of the femoral neck, and aseptic necrosis of the femoral head.

With arthrosis, degenerative changes occur in the articular cartilage, which ultimately leads to wear and tear of the cartilage. Bone growths (osteophytes) form around the joint.

Due to wear and tear of the cartilage, a decrease in its thickness, a significant decrease in smoothness, as well as a change in the shape of the articular surfaces, friction in the joint increases, which leads to pain and progressive impairment of movement in the joint.

Aseptic necrosis of the femoral head is another cause of hip joint destruction. In this disease, the head of the femur loses its blood supply and is actually destroyed. The shape of the femoral head changes, the bone tissue that makes up the head is resorbed.

The articular surfaces of the acetabulum and the head of the femur no longer correspond to each other in shape, pain and impaired movement in the joint appear. Causes of the disease may include previous hip dislocations, trauma at birth, long-term treatment with corticosteroids, and some infections.

The main goal of replacing a joint with an artificial one for any of the degenerative diseases is to reduce pain and return movement. To do this, the damaged surfaces are replaced with artificial ones, resulting in the return of smooth and painless movements in the joint.

A femoral neck fracture is also an indication for joint replacement surgery.

When the femoral neck is fractured, the blood supply to the head is disrupted, resulting in its gradual destruction.

Healing of the fracture is impossible under these conditions; surgery is the only way to mobilize the patient and return him to daily activities.

Which friction pair is right for you?

Metal-polyethylene

. Suitable for both men and women planning to lead a moderate lifestyle without exercise. It is generally accepted that this friction pair can be safely used in people of older and possibly middle age groups, but the age criteria are not precisely defined. Many people believe that this friction pair is justified in people over 60 years of age, but in many countries it is also used in people over 50 and 40 years of age. Wear products do not have a harmful systemic effect, are not absorbed into the blood, but can only have a harmful local effect, disrupting the quality of the bone around the endoprosthesis and theoretically contribute to loosening of the stem or, less commonly, the cup. Technologies for making cups from high molecular weight polyethylene are being improved and modern materials have much greater wear resistance and less toxicity of friction products than previous types of medical high molecular weight polyethylene.

Metal-metal

– is more suitable for patients with a high level of physical demands, for example, if after surgery it is planned to lead a particularly active lifestyle when a large range of movements is needed. We are wary of this friction pair if pregnancy is planned after the operation. There is evidence that metal ions penetrate into the fruit (concentrations increase by 15%) and may have an adverse effect. There is no clear evidence of harm to the child - at least there have been no reported cases of developmental problems and illnesses in children whose mothers underwent metal-to-metal hip replacement. But one must be wary as this friction pair is increasingly used and the lack of known cases of harm to children may be due to statistical error due to the relatively small number of such operations in the past.

Ceramics-ceramics

. Suitable, perhaps, for all patients of all ages. The feasibility of using a ceramic-ceramic friction pair must be correlated with its cost. Often, for many patients, cheaper friction pairs will be absolutely enough. The remaining options for friction pairs (ceramics-polyethylene, ceramics-metal) combine the advantages and, unfortunately, disadvantages described above.

For young patients, modern manufacturers offer endoprostheses with a shortened stem - this allows the operation to be performed with greater preservation of the femur without reducing the reliability of fixation.

PREPARATION FOR HIP ENDOPROSTHETICS

The decision about surgery is made by the doctor together with the patient. After determining the medical history, the doctor performs a thorough clinical examination to measure the patient's current range of motion, pain level, and functionality. During the examination of the patient, the surgeon examines radiographs, as well as CT and MRI data.

A thorough and complete medical examination before surgery will also be required. This is done in order to minimize the risk of complications during surgery. If a long surgery is expected or the patient's hemoglobin level is below normal, blood transfusions may be required after or during surgery. Prevention of thromboembolic complications is mandatory.

How does the operation end?

At the end of the operation, a bandage and drainage are applied and the remaining blood parts are removed. After this, the first x-ray is taken to monitor the results of the operation and evaluate postoperative measures. The location of the total hip endoprosthesis within the body. © Implantcast In the ward, the operated leg is covered with pillows or placed in a special splint. The patient's movement occurs depending on the patient's condition and with the help of a physiotherapist. The program includes walking training, including walking up and down stairs. They also train to independently carry out such daily procedures as washing, going to the toilet, putting on socks, shoes, and trousers.

TYPES OF ENDOPROTHESESES

There are several main types of endoprostheses - cementless and cemented.

Cemented endoprostheses are held in the bone using special cement that fixes the metal to the bone. The surface of cementless prostheses is made in such a way that bone tissue grows into it over time, due to which the prosthesis is held in the bone. In order for the endoprosthesis to grow in, the bone is processed with special tools.

Both types of fixation of endoprostheses are widely used in medical practice. Also, in some cases, a combination can be used when, for example, the acetabular component (cup) is fixed with cement, and the femoral component (stem) is cementless. The decision about whether to use a cemented or cementless endoprosthesis is made by the surgeon, based on the patient’s age, lifestyle, and the quality of his bones.

The endoprosthesis consists of two main parts.

The acetabular component (cup) replaces the articular surface of the acetabulum. The acetabular component shell is made of metal, inside which is placed a plastic or ceramic liner that is in direct contact with the femoral component.

The femoral component replaces the head and neck of the femur and is usually made entirely of metal. In some designs of the endoprosthesis, the head can be made of ceramic.

Endoprosthetics can be total, when both components are replaced, or unipolar. With unipolar endoprosthetics (hemiarthroplasty), only the femoral component is changed. Hemiarthroplasty is commonly performed for femoral neck fractures in elderly and frail patients.

With this type of endoprosthetics, the earliest verticalization of the patient is allowed, the very next day. This significantly reduces the risk of thromboembolic and hypostatic complications in elderly, weakened patients with femoral neck fractures. Equally important is the shorter operating time for hemiarthroplasty compared to total arthroplasty, which also reduces risks during anesthesia and blood loss during surgery. Currently, our clinic uses modern cemented bipolar hip replacements. A bipolar endoprosthesis is a modern type of unipolar prosthesis in which the head is double.

This design of the endoprosthesis increases the service life of the prosthesis, increases its stability and range of motion.

Difference between cemented and cementless endoprosthetics

The main differences lie in the method of securing the implant to the bone. The implants themselves differ in material, coating and appearance. In addition to cemented and cementless, there are also reverse hybrid endoprostheses.

Types of implants according to the method of fixation:

• Cement prostheses are fixed with polymer cement made from polymethyl methacrylate. This allows you to “adjust” them to any, even very wide, canal of the femur.
• Cementless endoprostheses are installed using the press-fit method , that is, by “tight fit”. The implant components are hammered into the bone canals. Before installing the prosthesis, the shape of the bone canals is corrected with rasps.
• The femoral components of hybrid endoprostheses are fixed using the “tight fit” method, the remaining components (acetabulum or tibial, patella) are fixed with cement.

Table 1. Main differences between cemented and cementless prostheses.

Minimally invasive endoprosthetics in the Czech Republic: doctors, rehabilitation, terms and prices.

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MORE ABOUT HIP ENDOPROSTHETICS OPERATION

The surgeon accesses the hip joint; a skin incision is made in the upper third of the thigh. Once the hip joint is exposed, surgeons dislocate the worn head of the femur from the acetabulum.

Then the damaged head and neck of the femur are resected with a special electric saw.

Next, the acetabulum is processed using special cutters. During the treatment, worn-out cartilage is completely removed and a hemisphere is formed into which the acetabular component will be implanted.

After shaping the acetabulum, the surgeon fills the socket with bone cement and installs an appropriately sized acetabular component. At this stage, the correct spatial orientation of the acetabular component at the correct angle is important. This affects the service life of the endoprosthesis and the likelihood of complications developing in the postoperative period.

After the cement has hardened and the acetabular component has been fixed, the surgeon begins to work on the femur. At this stage, the bone canal of the femoral canal is developed with special rasps to the required size.

Next, cement is placed into the prepared canal in the femur and the femoral component is installed.

The head of the required size is selected and the femoral component is reduced into the acetabular one.

The surgeon then checks hip stability and range of motion.

Once the surgeon is sure that everything is installed properly, the wound is sutured layer by layer. Drains are installed for a day. The patient is sent to a special ward in the postoperative department.

The patient’s rehabilitation begins from the first day.

Possible complications

Their list includes infectious, thromboembolic complications, dislocation of the head of the endoprosthesis. The incidence of these complications is low. The clinic uses every opportunity to prevent them. You must listen carefully to the attending physician and the head of the department, only in this way can you achieve the desired result.

If some surgeon says that he has no complications, then he is blatantly lying. Any surgeon has them, regardless of age, work experience, clinic and country in which he works. Pain after hip replacement is normal and goes away quickly with proper treatment.

HOW WILL THE POSTOPERATIVE (REHABILITATION) PERIOD WILL BE?

The duration of rehabilitation depends primarily on the type of fixation of the endoprosthesis components. With cement fixation, full weight bearing is possible almost immediately after surgical treatment.

If a cementless fixation method was used, it is recommended to limit the load on the operated limb for 8-12 weeks from the moment of surgery; during this time, you need to walk with the help of crutches, in order for bone tissue to grow into the surface of the endoprosthesis components, then you can proceed to full load.

The main risk after total arthroplasty is dislocation of the head of the femoral component of the endoprosthesis. Therefore, the combination of hip flexion and abduction is contraindicated for 6 months after surgery (the period of recovery of the hip joint capsule dissected during surgical treatment), sitting on low sofas and couches, and avoiding deep bends through the hip to the floor. You should avoid crossing the operated lower limb with a healthy one, or being in a cross-leg position. Driving is possible 6 weeks after surgery.

Restoration of working capacity is possible after 6 weeks (if the work is not associated with increased physical activity and prolonged standing), 12 weeks for patients whose work is associated with physical activity.

Advantages and disadvantages of fixation methods

Undoubtedly, both types of endoprosthetics have both advantages and disadvantages. However, in general, the outcome of the operation depends not only on the cost and characteristics of the implant. As we have already said: everything is in the hands of the surgeon!

Table 2. Pros and cons of different types of endoprosthetics.

What happens after surgery?

The day after surgery, the drains are removed. Dressings are changed daily by our doctors. Initially, after surgery, patients are prescribed pain therapy. In this case, the choice is between the latest pain-reducing catheters and well-absorbed medications. One day after surgery, you are allowed to stand up and load the implant.

Sleeping on the operated side is allowed almost immediately, but sleeping on the opposite side is not recommended for the first six weeks.

Depending on which method of access to the joint was used, certain movements should be avoided in the first weeks to avoid the head of the endoprosthesis falling out of the socket (displacement of the endoprosthesis fixed in the bone, as a rule, does not occur in this case).