The implantation of a hip prosthesis is a surgical procedure in which the damaged cartilage and the bones forming the joint are replaced with artificial materials.
The hip joint consists of a ball that lies in a cavity. The concave, calyx-shaped part of the joint that includes the femur is a pelvic bone called the pelvic socket, acetabulum, or medically acetabulum; the ball, on the other hand, is formed by the head of the femur.
In a complete replacement of the hip, the bony parts of the joint are surgically removed and replaced with a prosthesis made of metal or ceramic.
About half of the femural part is inserted into the femur like a stalk, while the shell-shaped part of the hip replaces the pelvic socket.
Once the prosthesis is inserted into the femur, it is fastened with bone cement (methyl mathacrylate).
Alternatively, there are also cementless prostheses with microscopic pores that allow the growth of the femur in the shaft. The cemented hip prosthesis has a longer lifespan and is mainly used in younger patients.
The insertion of an artificial hip joint is considered if the pain is so great despite taking anti-inflammatory and / or analgesic drugs that the normal functions of the hip are prevented.
How do you prepare for the implantation of a hip prosthesis?
A few weeks before the operation, various preparatory measures must be taken.
To improve the chances of success of the procedure, a physiotherapeutic program should be followed with exercises aimed at strengthening and stretching the muscles of the entire lower extremity.
An improved condition of the cardiovascular system helps to get back on its feet faster after the procedure.
The surgeon may advise a blood sample, because a blood transfusion may be necessary when implanting the hip prosthesis.
Before the operation, a check-up by the orthopedist must take place, but the family doctor should also carry out a thorough examination before such a delicate procedure.
To prevent infection, tooth extractions or other dental treatments should not be carried out in the first months after surgery; these should be performed before the procedure.
The patient must list to the orthopedist all the medications he is currently taking; this will then decide whether the intake should be interrupted or the dosage changed.
A few days before the operation, blood and urine are examined; if necessary, the surgeon will also prescribe an ECG and chest X-ray.
The time after the procedure should also be considered: footwear and some furnishing areas must be adjusted, forearm crutches and walkers are needed for the first two months after the operation.
How is the surgical treatment carried out?
The insertion of a hip implant can be performed in the conventional way or by a minimally invasive surgical technique. The main difference between these two procedures lies in the size of the incision.
The standard procedure is performed to relax the muscles under general anesthesia, causing a temporary, deep state of sleep.
In this way, the patient is prevented from feeling pain during the operation and consciously perceiving the procedure.
Alternatively, spinal anesthesia can be performed if the patient’s condition allows it.
The doctor makes an incision on the outside of the hip and shifts the muscles that attach to the top of the femur to expose the joint.
Then the head of the femur is removed with the help of a saw.
The artificial hip joint is attached to the femur with cement or a special material, whereby residual bone and new joint fuse together.
After the femural part is replaced, the surgeon prepares the articular surface of the pelvis (acetabulum); he removes the damaged cartilage and inserts the pelvic socket.
Then the new femur head is inserted into the acetabulum socket.
The surgeon may place a drainage to allow any fluid (body fluid) to drain away.
Finally, the muscles are repositioned and the incision is closed.
The majority of hip implants are inserted using the standard technique, i.e. a 20 cm incision along the outside of the hip; For some years now, some surgeons have been using a less invasive surgical technique,
with one or two incisions of 2-5 cm in length. The subsequent surgical intervention is carried out in the same way as with the standard method, only through these small incisions.
The execution of small incisions has several advantages: the blood loss is less, as well as the pain after the procedure, the hospital stay is shortened, the surgical scar is smaller and heals faster.
The prerequisite, however, is that the surgeon is very familiar with this technique.
Scientific studies show that the results of the minimally invasive technique can be worse than with the conventional surgical method if the surgeon does not have the necessary expertise.
Since blood loss can occur when an artificial hip joint is inserted, a blood transfusion may be necessary. For this reason, an autologous blood reserve should be prepared before the procedure.
How is the care provided after the operation?
After the operation, a hospital stay of about 10 days is planned, during which the patient is cared for by the surgical team; in addition, rehabilitation begins with the physiotherapist.
It is important to put a pillow between your legs in bed so that the new joint is held in the correct position and a risk of dislocation is avoided.
In the first few days after surgery, physiotherapy begins to move the lower extremities without strain, with exercises for the ankle, knee and hip.
It is important that the patient learns to adapt the daily activities and movements to the new situation. The surgeons agree that the introduction and internal rotation of the hip are among the forbidden movements.
Some orthopaedists prohibit joint flexion of more than 90° because otherwise there is a risk of dislocation for the hip joint currently inserted.
If the patient is finally allowed to leave the bed, he must learn correct behaviors regarding walking, sitting down and getting up from a chair, getting in and out of the car, using the bathroom.
A catheter is placed to urinate.
The rehabilitation should begin the day after the operation and the patient should be able to walk again a few days later with the help of a walker, forearm crutches or walking stick.
Physiotherapy must continue to be practiced at home or in the practice for a few more months.
In the first 2-3 months, the movements for flexion, introduction and internal rotation of the hip must still be performed very carefully, but as soon as the hip joint prosthesis is stably fixed, the orthopedist will give the green light to perform all movements without restriction.
After discharge from the hospital, the patient must not stop moving and walking, otherwise the state of health may not be fully regained.
An excellent physiotherapeutic exercise is riding on the ergometer (exercise bike), initially with a high saddle, which is later lowered to normal height.
Due to the age of the patients, rehabilitation in the water (hydrokinesiotherapy, water aerobics) is not always possible.
In the vast majority of cases, at the end of the procedure, the non-operated limb is shorter than the other.
This can be explained by the fact that both sides of the hip suffer from osteoarthritis, and the non-operated limb has a thinner layer of cartilage; therefore, a shoe raised by about 2-3 cm must be worn here.
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