- Benefits of Hemiarthroplasty
- Contraindications for hemiarthroplasty
- Possible consequences
Hemiarthroplasty is an incomplete prosthetics, which implies replacing only the head of the femur with an implant. The acetabular bed remains intact during the intervention, that is, it is not subjected to any manipulations. For the operation, special models of prostheses are used, consisting of a cone-shaped stem and an ellipsoidal head. The artificial head, rubbing against the natural cartilaginous surface of the acetabulum, is made of a biologically inert material: titanium alloy or corundum ceramic.
Hemiprosthesis are also called unipolar, partial or incomplete hip joint endoprostheses. They are not designed for normal and high physical activity, since prolonged and active movements of the replaced head in a pair of friction with biological cartilage will lead to rapid wear of the latter. As a result, you will soon have to turn to a total operation (to put a full-fledged prosthesis). Therefore, this tactic is only suitable for all people who lead a sedentary lifestyle.
Hemiarthroplasty is indicated for persons of the elderly, senile age group, who, as a result of an injury, have a fracture / dislocation of the head, a fracture of the femoral neck. What is the femoral neck is shown in the picture above. The same category can be recommended for necrosis of the proximal femoral epiphysis or after unsuccessful osteosynthesis. But in order to recommend such a technique, the physician must ensure that the contours, depth and integument of the natural bed of the pelvic bone are in good condition.
Benefits of Hemiarthroplasty
Every year in Russia, per 100 thousand population, an average of 150 people receive a hip fracture, and the bulk of them are people of advanced age and older. Non-surgical therapy, osteosynthesis in PBS very rarely end in a successful outcome. They are associated with exorbitant risks of serious complications due to the forced prolonged stay of the patient at rest.
Frequent consequences of such therapeutic approaches are pressure sores, hypostatic pneumonia, thromboembolism, infections of the urinary tract, etc. Not to mention the fact that the guarantee of normal hip union is extremely low, and in the first year after discharge from the hospital, the mortality rate reaches 40% – 60%. The explanation for this is a weakened organism with scarce biochemical reserves due to age characteristics.
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Based on the foregoing, experts are unanimous in the opinion that for older people, the most acceptable type of treatment for neck / head injuries is endoprosthetics. The advantages in this case are on the side of the hemiarthroplasty, and not the total replacement of the hip joint. Compared to complete endoprosthetics, hemiarthroplasty differs in:
- less traumatic;
- complete preservation of the osteochondral tissues of the acetabular part;
- a more “simple” technique for installing an endoprosthesis;
- the possibility of using spinal epidural anesthesia;
- lower total blood loss (up to 150 ml);
- less severe pain during rehabilitation;
- insignificant risks of intra- and postoperative complications;
- reduced time of the operational process (40 min.);
- short rehabilitation period.
The operation does not have a strong stressful effect on the body of an elderly person. It especially justifies itself in the case of the presence of concomitant complex pathologies – diabetes mellitus , heart disease, pulmonary failure, etc. Less expensive surgical aid for people “aged”, the most economically unprotected cell of society today, is another plus of hemiarthroplasty.
Unipolar prosthetics are tolerated relatively comfortably due to the small invasion field. It allows in the early period to activate and put an elderly person on his feet, effectively eliminate pain and motor deficits, and quickly restore the ability to self-care. But most importantly, the sparing procedure for replacing the hip joint makes it possible to extend life, improve its quality at least to the level that preceded the injury. The forecast for positive results with timely performed surgery is 92% -95%.
Contraindications for hemiarthroplasty
Contraindications for incomplete hip replacement include:
- the patient’s age is less than 70 years old;
- coxarthrosis of the hip joint;
- detected damage to the bone and / or cartilage of the acetabulum;
- active infectious process in the planned area of the operation;
- allergy to implant materials;
- severe thrombosis of the veins of the extremities;
- intolerance to any of the types of anesthesia.
Despite the good characteristics of hip hemiarthroplasty, the technology is not without its drawbacks. The disadvantages of the monopolar prosthetics technique include:
- inability to use at a young age;
- short service life of hemiprosthesis (on average 5 ± 2 years), therefore, they are placed only in patients with the same expected life expectancy;
- high susceptibility to intense destruction of the second, non-implanted pole of the joint.
Before the intervention, the necessary laboratory and instrumental studies are carried out (electrocardiography, X-ray, ultrasound of the vessels of the extremities, etc.). Then the patient enters the operating unit, where, after the introduction of anesthesia (usually of a regional type), a surgical session begins.
- The patient is placed on a healthy side.
- In the projection of the affected area, the surgeon, using a small incision, creates an access using the posterior or anterior method of exposing the joint.
- The articulation capsule is subjected to a cruciform incision.
- Rotation of the hip opens the fracture area.
- Further, the specialist, acting with a surgical corkscrew, removes the head from the pelvic bed. Again, the bone and cartilaginous structures of the acetabulum are not affected at all.
- Afterwards, the osteotomy of the neck is performed on the desired area of the thigh by oblique intersection of the bone. Thus, the femoral head and partly the cervical region are removed.
- Then they begin to prepare the femoral canal for the introduction of the leg of the hemiprosthesis into it. The bone canal is opened and with the help of cutters is processed by reciprocating movements to the required size and shape.
- The stem of the endoprosthesis is placed into the prepared bone cavity. Depending on the type of fixation of the prosthesis, the leg is hammered into the bone until it stops or immersed in acrylic cement previously introduced into the canal.
- A spherical piece is installed on top of the isthmus of the leg, which will functionally replace the natural head.
- Next, the artificial head is inserted into the natural articular cavity of the pelvic bone. The reconstructed joint is tested for range of motion and tendency to dislocation.
- The operation ends with drainage of the wound, suturing the capsule and layer-by-layer suturing of all intersected soft tissues.
Early hemiarthroplasty significantly increases the chances of a good prognosis and acts as a preventive measure against the development of congestive pneumonia and other complications that shorten the patient’s life. Therefore, with such a complex problem as a fracture of the femoral component of the joint, the decision to perform an operation should be made urgently, while the injury is still “fresh”.
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The risks of developing negative reactions at the time or after the intervention are insignificant. Early and late complications of hemiarthroplasty are manifested in the form of:
- an infectious process within the operating field;
- dislocations of the femoral component;
- pain syndrome associated with aseptic loosening of the endoprosthesis;
- periprosthetic fractures;
- shortening of the limb;
- erosion and protrusion of the acetabulum;
- formation of heterotopic ossification.
Mortality after hemiarthroplasty, according to statistics, does not exceed 2.5%. Undoubtedly, the time of a patient’s seeking medical help, the surgeon’s qualifications and experience, the quality of the patient’s preoperative preparation and the level of organization of rehabilitation directly affect the likelihood of complications.
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