Endoprosthetics (replacement) Of The Hip Joint

2024 Author: Josephine Shorter | [email protected]. Last modified: 2024-01-07 17:49

Endoprosthetics (replacement) of the hip joint

Content:

• The structure of the hip joint
• Why do you need endoprosthetics?
• Contraindications to surgery
• Types and types of endoprostheses
• Cementless and cementless endoprosthetics
• Preparing for surgery
• What happens during surgery?
• Possible complications
• Real results
• Rehabilitation after prosthetics
• This should never be done!

Endoprosthetics of the hip joint is one of the most modern methods of surgical treatment of diseases of the musculoskeletal system. During the operation, the pathologically altered tissues of the structures that make up the hip joint are replaced with artificial prostheses.

Structure and function of the hip joint

The hip joint is considered to be the largest joint of the bones in the human body. The loads that he has to experience in the process of life are very large. After all, it connects both lower limbs to the pelvis.

The formation of the hip joint involves:

• The head of the femur is the spherical upper end of the femur;
• The acetabulum is a funnel-shaped deepening of the pelvic bones in which the femoral head is fixed;
• Articular cartilage - soft cartilaginous tissue with a jelly-like lubricant that facilitates movement;
• Intra-articular (synovial) fluid is a jelly-like mass that nourishes the cartilage and softens friction between the articular surfaces;
• The ligamentous apparatus and the joint capsule are dense connective tissue that holds the articular surfaces and ensures the stability of the hip joint.

The muscles and their tendons, which are attached to the hip joint, contract and provide movement in it. A healthy hip joint is mobile enough to move in almost all planes and directions. This range of motion is enough to adequately support the function of support, walking and strength exercises.

Why may endoprosthetics be required?

It is quite natural that there should be significant indications for the replacement of the hip joint with an artificial prosthesis. They are based on such a destruction of the components of the joint, in which a person either experiences excruciating pain or is not able to perform elementary movements of the affected limb. In other words, the joint ceases to correspond to its physiological purpose and becomes an unnecessary part of the body, as it sharply worsens the quality of life. In such cases, arthroplasty is the only way out of their situation.

Among the diseases that can provoke destructive changes in articular structures, the most common are:

• Deforming osteoarthritis of the hip joint (coxarthrosis), which occurs simultaneously on both sides with 2 and 3 degrees of the disease;
• Coxarthrosis of the 3rd degree with deformation of one joint;
• Unilateral deforming arthrosis of the hip joint of 2-3 degrees in combination with ankylosis (complete immobility) of the knee or ankle joint of the affected limb;
• Defeat of one hip joint with coxarthrosis of 2-3 degrees in combination with ankylosis of the same joint on the opposite side;
• One- and two-sided ankylosis of the hip joints with ankylosing spondylitis and rheumatoid arthritis;
• Destruction of the femoral head (aseptic necrosis) caused by injury or poor circulation;
• Traumatic injuries to the head and neck of the femur in the form of a fracture or pseudarthrosis in persons over 70 years of age;

• Malignant tumors in the ankle joint that require surgical treatment. After tumor resection, simultaneous endoprosthetics is performed.

It is advisable to replace the hip joint with an artificial prosthesis only if the structure and functions of the joint are so impaired that physical activity and walking become almost impossible. In this case, the actual possibilities of performing and the benefits of the operation in each specific case must be taken into account!

Contraindications to surgery

Unfortunately, people who need hip arthroplasty are not always able to perform such an intervention.

The main limitations include:

• Clinical cases when a person, for any reason, is not capable of independent movement. The performed endoprosthetics does not eliminate the existing defect and therefore is considered inappropriate;
• Chronic pathology in the stage of decompensation (heart failure, severe heart defects and arrhythmias, cerebrovascular accidents with neurological deficit, hepatic-renal failure). The operation carries a high risk of exacerbating existing problems;
• Chronic lung pathology, accompanied by severe ventilation and respiratory failure (asthma, pneumosclerosis, bronchiectasis, emphysema);
• Any inflammation of the skin, soft tissues or bones in the hip joint;
• Focuses of chronic infection in the body, requiring sanitation;
• Septic conditions and reactions. The operation is not performed even for those patients who have had sepsis for several years, since there is a high risk of suppuration of the prosthesis;
• Paresis and paralysis of the limb subject to endoprosthetics;
• Severe osteoporosis and insufficient bone strength. Such patients, even after perfectly performed surgery, can break the femur or pelvic bones during normal walking;
• Severe cross-allergy to various medications;
• Pathological conditions, accompanied by the absence of a medullary canal in the femur.

Types and types of endoprostheses

The endoprosthesis, which will replace the pathologically altered hip joint, must have sufficient strength, secure fixation, high functional abilities and be sufficiently inert with respect to the tissues of the human body. All these requirements are met by products made of high quality metal alloys, polymers and ceramics. As a rule, one endoprosthesis contains a combination of all these materials. This is due to the fact that in its appearance and qualities, the product should resemble the human hip joint.

Its components are presented:

• Endoprosthesis cup. This is the part that should replace the acetabulum of the pelvic bones. It is usually made from ceramic. But there are plastic cups;
• The head of the prosthesis. It is a metal spherical piece coated with a polymer. In this way, it is possible to achieve the most soft sliding when the head rotates in the cup of the prosthesis during the movement of the limb;
• The leg of the prosthesis. It is made exclusively of metal, since it experiences the greatest stresses in comparison with other parts of the endoprosthesis. If the head of the prosthesis imitates the head of the femur, then its stem replaces the neck and the upper third of the femur.

Another fundamentally important rubric in the classification of products for hip joint replacement is their division into unipolar and bipolar. The first type is represented exclusively by the leg and head, which replace the corresponding structures of the femur. In this case, the joint will be represented by an artificial lower part and a natural acetabulum. Such interventions have been widely performed in the past. Due to poor functional results and a large number of destruction of the acetabulum with the failure of the endoprosthesis into the pelvic cavity, modern orthopedists practically do not perform such operations.

Bipolar endoprostheses are often called total. This means that the composition of the product is represented not only by the part that prostheses the femur, but also by the cup that acts as the acetabulum. Such endoprostheses are perfectly fixed in bone tissues and are maximally adapted, which significantly increases the effectiveness of the operation and reduces the number of complications. This is especially true when performing arthroplasty in elderly people with symptoms of osteoporosis and in young physically active individuals.

The service life and potential use of a hip endoprosthesis depends on the quality of the materials from which it is made. The strongest are metal endoprostheses, which last about 20 years. But they have less impressive functional results in relation to the motor activity of the affected limb. The most optimal prostheses in terms of locomotor activity / service life are total endoprostheses made of metal, polymers and ceramics.

Cementless and cementless endoprosthetics

The choice of the method for fixing the endoprosthesis is considered a very topical issue, both for specialists and for their patients. In this respect, things are not so simple. After all, metal and ceramic materials must be firmly connected to the bones. Only if this condition is met, it is possible to perform the functions of support and walking with a sick limb.

Having determined the correct type of endoprosthesis and its size, the doctor chooses the method of connecting the prosthesis with the tissues during the surgical intervention, guided by the following tactical decisions:

• Fixation of the endoprosthesis using cement - a special biological glue, which, after hardening, will firmly connect the bone tissues with the structures of the endoprosthesis;
• Cementless fixation. These products have a special design and are arranged in such a way that on their surface there are many small projections, depressions, irregularities and holes. Over time, bone tissue grows in them, and the prosthetic bone becomes one with the endoprosthesis;
• Hybrid or mixed fixation. It involves a combination of cement and cementless methods. In this case, the stem is fixed in the femur with cement, and the cup is screwed into the acetabulum.

Long-term observations of patients after such interventions made it possible to draw the following practical conclusions:

• The cement creates a very high temperature when it cools. This leads to the acceleration of the destruction of the surrounding bone tissue, which can cause the failure of the prosthesis and its failure into the pelvic cavity;
• Cement fixation speeds up rehabilitation and shortens the recovery time of patients, but its use is limited in patients with osteoporosis and the elderly;
• Cementless endoprosthetics is associated with lengthening the duration of full rehabilitation. Patients have to observe a limited motor regime for much longer due to the high risk of impairment of the stability of the prosthesis;
• The most optimal is endoprosthetics by combined methods of fixing different parts of the product. This rule is the gold standard of treatment for patients of all age groups.

Preparing for surgery

All patients who need endoprosthetics and who have passed the necessary studies to determine the condition of the hip joint (X-ray, MRI, ultrasound) must also undergo a comprehensive examination. This is necessary in order to exclude the presence of possible contraindications.

The complex of diagnostic measures includes:

• General clinical blood and urine tests;
• Determination of blood glucose levels, and for persons with diabetes mellitus - glycemic profile;
• Biochemical blood test;
• Determination of blood electrolytes (potassium, magnesium, sodium, calcium, chlorine);
• Study of blood clotting (coagulogram, prothrombin index, clotting time and duration of bleeding);
• Determination of blood group and Rh factor;
• Blood test for RV and Australian antigen;
• ECG;
• Study of the functions of external respiration;
• X-ray examination of the lungs;
• Consultations of narrow specialists in the presence of a corresponding chronic pathology.

No special preparatory measures are required before hip arthroplasty. If no contraindications are found during the examination, the date of the operation is assigned. A light dinner is allowed the night before, but not earlier than 8 hours before the intervention. In the morning, the skin in the hip joint and thigh area is carefully shaved. Eating and drinking water is prohibited. Before the patient is transported to the operating room, elastic bandaging of the legs is performed, a prophylactic dose of an antibiotic is administered and premedication is performed.

What happens during surgery?

After the patient is delivered to the operating room and placed on the operating table, anesthesia is performed. Usually the method of anesthesia is chosen by the patient in conjunction with the anesthesiologist. Since the duration of the operation is from 1.5-2 to 3-3.5 hours, either spinal anesthesia or a full-fledged combined anesthesia with controlled breathing and complete muscle relaxation are considered optimal. The first method is less harmful and therefore preferable for elderly patients.

After anesthesia, the surgeons process the operating field and access the hip joint. The size of the incision, which passes through the central part of the joint, is about 20 cm. Then the capsule of the joint is opened and the head of the femur is removed into the wound. Its resection is performed along the transtrochanteric line until the medullary canal is exposed.

The bone is modeled in accordance with the shape of the endoprosthesis, which is fixed in it in one of the optimal ways (most often with the help of cement). Then the acetabulum is processed with a drill with a special nozzle in order to completely remove the articular cartilage from its surface. The prosthesis cup is installed and fixed in the prepared funnel.

The prosthetic surfaces are matched and strengthened by suturing the dissected tissue. An active aspiration drainage is installed in the wound, through which the discharge will flow. A bandage is applied.

Possible complications

Endoprosthetics of the hip joint is a major and complex intervention.

Its complications can be:

• Bleeding from a postoperative wound;
• Formation of blood clots in the veins of the lower extremities with migration to the vessels of the lungs and pulmonary embolism;
• Suppuration of the postoperative wound and endoprosthesis;
• Hematoma of the operated area;
• Failure of the endoprosthesis and its rejection;
• Problems from the heart and brain in the presence of chronic pathology (coronary artery disease, atherosclerosis, discirculatory encephalopathy, etc.);
• Dislocation of the endoprosthesis.

Correctly defined indications and contraindications for performing arthroplasty, combined with thorough preparation for the intervention and the sequence of its implementation, minimize the risk of postoperative complications. But they cannot be completely excluded, even if all the rules and recommendations are followed.

Real results

According to statistics based on long-term follow-up of operated patients and the personal experience of leading specialists involved in hip arthroplasty, most patients are satisfied with the treatment results. If the operation is performed in somatically healthy persons of a relatively young age who do not have concomitant diseases, the functional abilities of the hip joint are almost completely restored. This allows a person to walk and exercise. Sports and movements associated with the power tension of the lower extremities are impossible. Patients are either unable to perform them, or in the course of their implementation, there is a violation of the integrity of the endoprosthesis.

As with any operation, arthroplasty is not complete without complications and unsatisfactory results. They are mainly associated with old age, concomitant diseases and non-compliance with the treatment regimen by patients in the early and late postoperative period. More than 20% of the operated patients expected better results from endoprosthetics in comparison with those obtained.

Endoprosthetics using the MIS method - patient review

Rehabilitation after hip arthroplasty

Rehabilitation measures to restore physical activity after hip arthroplasty begin from the first hours after surgery. They include exercise therapy, breathing exercises, early activation. The operated limb must be in a state of functional rest, but movements must be performed. They can be active, when the patient contracts the muscles on their own, and passive, performed with the help of medical personnel or relatives. The main rule of the postoperative and recovery and rehabilitation periods is the sequence of increased loads.

The first day after surgery

Most patients carry out it in the intensive care unit. This is necessary in order to monitor basic vital signs around the clock and instantly respond to any pathological changes. Within a few hours after the intervention, the person can be in a sitting position with the legs down. Movement in the knee and ankle joint is not limited.

The prosthetic hip joint must not be flexed more than 90 ° C, as this can lead to a violation of its structure and fixation in the bones. It is better to sit down under the supervision of medical personnel or relatives. They can help move the operated limb and help in case of dizziness (this sometimes happens when a person moves from a horizontal position to a vertical one). Patients with a history of comorbidities and general disorders must be prevented from forming pressure sores (change in body position, light massage of the skin of the back and in the area of bone protrusions, treatment with camphor alcohol, control over the condition of linen)

As for the range of permitted movements, the patient can:

• Perform movements with a healthy limb in any volume;
• Getting out of bed with support exclusively on a healthy leg is allowed only for young people without concomitant diseases, if their general condition allows it;
• Wiggle your fingers and do slight flexion at the knee joint of the operated leg;
• Lift up the operated straightened lower limb, lifting it from the bed as much as possible;
• Perform active movements of the upper limbs in any volume;
• Walking on the first day is not recommended;
• Don't lie on your side.

Patients can be placed in a semi-sideways position with a pillow or a large fabric roller between the knees;

When can I get out of bed?

Getting out of bed on your own after hip arthroplasty during the first day is strictly not recommended. Leaning on a healthy leg without additional devices is contraindicated for several weeks. Crutches, walking sticks and other orthopedic products are used as aids to rehabilitation. If the general condition after the operation is not disturbed, you can get up the next day. Most patients feel weakened and refuse early activation.

When can I walk?

Walking is allowed 2-3 days after surgery. It is imperative that all conditions are met when moving to a vertical position. This is, first of all, the movement of the operated limb with the help of hands or a healthy leg, after which it hangs from the bed. Leaning on your good leg and crutches, you can get up. At the same time, the diseased leg should be in a suspended state, since any attempts to lean on it are strictly prohibited for a month. The use of crutches when walking is recommended for at least 3 months.

If the recovery period proceeds without complications, in the future you can use a simple cane as an aid for support. It is allowed to lean on the sore leg after a month. In no case should you put all your weight on it. You need to start with exercises in the form of abducting the leg to the side, followed by adduction, as well as raising and lowering it, while in a standing position. The load should begin with a light support, which for 2 months cannot exceed half the patient's weight, excluding the weight due to obesity. Full walking without support is possible in 4-6 months.

Any increase in exercise intensity and range of motion should occur gradually. The optimal time for the transition from one type of rehabilitation devices to another is 5-6 days!

How to eat right?

One of the most important elements of the postoperative period is proper nutrition of patients. The diet should be enriched with a sufficient amount of protein, vitamins, trace elements and other nutrients. Since the physical activity of patients is limited, it is not worth increasing the calorie content of food. Excess energy substrate, which will not be consumed by the body, will turn into fatty deposits and increase the recovery time. It is better to refuse pastry products, fried and fatty foods, smoked meats, pickles and seasonings. The main emphasis is on lean meats, poultry, fish, vegetables and fruits in raw and boiled form, eggs, cereals. Any alcoholic drinks, strong coffee and tea are strictly excluded.

Terms of treatment

Most patients stay within the walls of a medical institution for 2-3 weeks. This is necessary in order to control the healing of the postoperative wound. In typical cases, the postoperative stitches are removed after 9-12 days. The drainage from the wound is removed as the discharge ceases (on average, after 2-3 days). The expediency of staying in the hospital after removing the stitches is due to the need to teach the patient and relatives the rules of behavior and basic rehabilitation skills. After 3 months, an X-ray examination of the hip joint is mandatory. This is necessary in order to determine the state of fixation of the endoprosthesis and the bone formations in which it is located.

How long does rehabilitation take?

After discharge from the hospital, it is advisable to consult with a rehabilitation doctor who will draw up an individual rehabilitation plan. Under the control of this plan, the recovery period will be as short and safe as possible. Most active patients return to their usual lifestyle after 6 months. Until that time, it is better to use rehabilitation means that minimize the load on the operated limb and the prosthetic hip joint.

This should never be done

Regardless of the length of the postoperative period, you cannot:

• Use too low chairs or a toilet;
• Cross the lower limbs while lying on your back or on your side;
• Sharply turn the body with fixed limbs and pelvis;
• Lay on your side without placing the roller between your knees.

All of the above actions can cause dislocation of the endoprosthesis, which will require reduction in a medical institution.

Endoprosthetics of the hip joint is an excellent achievement of modern medicine. Its effectiveness depends both on the correctness of the operation and on the patient's compliance with the conditions of the rehabilitation period.

The author of the article: Volkov Dmitry Sergeevich | c. m. n. surgeon, phlebologist

Education: Moscow State University of Medicine and Dentistry (1996). In 2003 he received a diploma from the Educational and Scientific Medical Center of the Presidential Administration of the Russian Federation.