Normal Hip joint
The Hip joint(Coxofemoral joint) is a globular joint which is composed of two joint surfaces that are coated with cartilage: the head of the femoral bone and the acetabulum, as well as connecting ligaments. The head of the femur is more than a hemisphere; it is situated in the acetabulum of the pelvis (cup-shaped spherical socket). The femur head moves in the acetabulum. The regular form of these two components of the joint and the coating of joint cartilage guarantee smooth and painless movement in the joint. Several strong ties (ligaments) keeps the head in the acetabulum (iliofemoral ligament, pubofemoral ligament, ischiofemoral ligament and the joint capsule), and also the good balance of the muscles surrounding the joint.
When is a hip replacement necessary?
Patients with complaints related to the hip joint, caused either by age alterations or illnesses and traumas, can make use of a hip joint replacement (endoprosthesis). The most common conditions leading to a hip joint replacement are:
1.Osteoarthritis
2.Rheumatoid arthritis
3.Traumatic arthritis
4.Avascular necrosis
5.Others
Osteoarthritis
The Osteoarthritis is a specific form of degenerative arthritis that is caused by either overload or age alterations. In this case, the joint cartilage, which normally coats the surfaces of the femur head and a part of the acetabulum, grows thinner, gets uneven and leads to higher friction of the joint surfaces. This causes erosion and deformation of the bone structure, followed by pains, stiffness, decreased volume of mobility. The early symptoms of Osteoarthritis can be treated with medications, physiotherapy and rehabilitation procedures. But if the pains have got so violent that the patient can’t be put on medication or if the daily volume of mobility has already greatly decreased, then hip replacement is needed.
Rheumatoid arthritis
This is a chronic autoimmune disease that causes inflammation of the synovial membrane, which coats the joint capsule inside. It can also lead to bone, cartilage, ligaments and muscles destruction and deformation.
Traumatic arthritis
The Traumatic arthritis is a form of arthritis, caused by hip joint traumas. The damaged surface of the joint cartilage can lead to increased friction causing arthrosic deformations in the joint, which later result in pains and decreased volume of mobility.
Avascular necrosis
It is caused by loss of blood supply to the femoral head. As a result of this, parts of the bone of the head die, the cartilage of the joint comes unstuck, the bone exposes and gets deformed, which leads to severe arthrosic changes. There are pains and the volume of mobility is limited.
Other causes
Other changes of the hip joint that lead to the need of endoprosthesis are:
-bone tumours (benign or malignant) can alter the form and congruence of the joint surfaces and also cause interruption of the blood supply to parts of the joint, while at the same time they damage the cartilage of the joint;
-Paget disease is most common among elderly people. Bones enlarge and become fragile, the femur is prone to fractures or deformations.
What is the best age for endoprosthesis?
Most patients who need endoprosthesis of the hip joint are between 70 and 80. There are rarely people under 30 or over 85 who need such an operation.
In most of the cases elderly people with Osteoarthritis are in need of endoprosthesis; this is also true for people of all ages with Rheumatoid arthritis.
How is the diagnosis made?
An anamnesis (the medical history) and a thorough physical examination enable the doctor to find out what the relation between the patient’s subjective complaints and the objective findings during the examination is. The symptoms (pain, decreased volume of mobility, contractures, limb shortening) are compared with the results of image and other tests ( X-ray pictures, scanner-if needed, magnetic resonance imaging-MRI). On this basis the doctor takes a decision whether endoprosthesis is needed or not. With the help of a blood test and an aspiration of the joint fluid, the prevention from systemic diseases (e.g. Rheumatoid arthritis) and bacterial infection of the joint, is made easier.
Preparation for endoprosthesis
The preparation for the operation starts a few weeks earlier. The aim is the total physical condition of the patient’s organism to be improved before the operation. The patient’s good physical and mental conditions are necessary so that he would easily be able to get used to walking on crutches or using a medical walker after the operation.
To evaluate the total condition of the patient’s organism, blood and urine tests are required.
Blood transfusion
During the operation blood transfusion is often needed. Autochemotransfusion is an option. For the purpose of this, the patient has to donate blood before the operation so that his own blood can be transfused to him during it. The first donation has to be done 40 days before the operation and the last one not later than 7 days before the operation. During blood-donation the patient has to be in good health, without temperature or any infections.
The orthopedist has to make sure that there aren’t any infectious processes in the patient’s organism; so this is the reason why blood and urine tests might be needed a week or two before the operation. There is a possibility of urogenital system infections, which are common for old people but are often unexpected by the patient. The patient can also be a carrier of other infections such as dental processes, pulmonary infections, etc.
Several days before the operation the following tests are required:
-Blood test (biochemistry, coagulation);
-ECG (electrocardiogram);
-a lung X-ray
Preliminary consultations before the operation
The patient needs to consult three more specialists before the operation:
-Radiologist
-Cardiologist
-Anaesthesist
The anaesthesist and the cardiologist specify what medications the patient has to take or stop taking the days before and after the operation.
The patient has to give the anaesthesist a list of all the medications he is taking at the moment.
Normally, medications which contain aspirin are not allowed 2 weeks before the operation.
Additional medical check-ups or consultations with other specialists may be required.
A Rehabilitation therapist can start training the patient how to walk on crutches or use a walker even before the operation, so as to make the rehabilitation process of the early post-operative period easier.
A dental check-up (out of hospital) may be required with a view to existing infections. The dental treatment before the operation prevents from infections that could affect the newly implanted hip endoprosthesis.
What is endoprosthesis of the Hip joint like?
During the operation, having cut the skin and separated muscles and other surrounding tissue, the surgeon reaches the hip joint. The joint capsule is cut and the components of the joint are being exposed. The femur head and neck are cut and removed. The femur duct is dilated so that to place the metal part of the prosthesis which is composed of a head (ball) and a stem with a neck.
The acetabulum is prepared to place the acetabular plastic component of the prosthesis. Then the endoprosthesis components are put together and the joint is repositioned.
The stem and the cup can be fixed to the bone by means of cement or without using any cement.
Prosthesis cement fixation
During the operation two components are mixed: powdered one(polymethyl methacrylate) and liquid one(its liquid monomer). This leads to the formation of paste-like substance (cement) which is put between the prosthesis and the bone. Then, in about 10 minutes time it hardens and becomes so durable that provides an excellent fixation of the prosthesis to the bone.
This method of prosthesis fixation remains “the gold standard” and is preferred one by orthopedists in most of the cases. Depending on their bone density, people over 60 are applied this method of fixation.
Uncemented fixation
Not all patients are suitable for cemented fixation. The studies have shown that premature aseptic loosening of the cemented prosthesis in younger and more active patients is very likely. Thus, there is a tendency today in younger patients to be used endoprosthesis coated with a material which enables the bone tissue to grow very close to the metal. In the course of time strong connective tissue is formed and it firmly fixes the metal to the bone. This requires an exact insertion of the metal into the thigh bone. The metal surface is composed of fine porous material which helps the bone grow inwards. This process is called “porous ingrowth” or “osteointegration”. This is, in fact, uncemented endoprosthesis. It is not suitable for elderly patients with osteoporosis.
Hybrid fixation
One of the prosthesis components is cemented fixed, the other-uncemented fixed.
Unipolar endoprosthesis
With some patients this type of prosthesis is preferred with the purpose of decreasing operative traumas. It includes substitution only of the damaged surface for prosthesis. It is carried out to people with avascular necrosis of the head who still have a remaining unaffected cartilage layer of the acetabulum.
What can the risks and complications be?
As it is with any major surgery, complications are not excluded here as well.
Some of the most common complications are:
Deep Venous Thrombosis (DVT)
DVT can be caused by any surgical procedure, but most often it affects patients after operations on the hip joint, the thigh, pelvis or knee. Thrombosis is a condition caused by blood clots (thrombus) in the large blood vessels of the lower limb or in the pelvic region. With DVT this happens in the veins.
Some symptoms of DVT are the following:
-swelling;
-warming;
-pains;
Orthopaedic surgeons take serious measures against DVT. Some of the most common preventive measures against DVT include:
-physical activity is encouraged as early as possible after the operation (mobility in bed and early verticalisation);
-elastic stockings against DVT which enable the blood to keep flowing;
-medications which prevent the formation of blood clot (Fragmin, Clexane, Fraxipane);
Infection
The risk of infection after hip joint endoprosthesis is less than 1%.
A superficial infection in the region of the operative wound is easily treated with antibiotics. A more serious infection may be caused by bacteria which have affected the bone in the presence of metal and cement. Such an infection may cause loosening of the prosthesis fixation. Some infections affect very early, even before patients are discharged from hospital. Others remain latent for months, even years after the operation.
The infection can spread to the implanted endoprosthesis from other infected parts of the body (bad teeth, urinogenital infection, dermal infections around the nails, hair follicle,etc.).
Your orthopedist may make you take antibiotics during subsequent operations on the colon intestine, bladder and others in order to decrease the risk of bacteria spreading to the already implanted endoprosthesis.
Dislocation (luxation) of the endoprosthesis
Endoprosthesis luxation is rare; it is to be found in about 3% of the patients having undergone an operation.
It can be as a result of individual’s unwillingness for collaboration and non-compliance with the doctor’s advice during the post-operative period.
Luxation can also be as a result of muscular disbalance.
Loosening
As a predominant reason for unsuccessful cement-fixed endoprosthesis is thought to be prosthesis loosening on the plase of contact of the bone to the metal or cement.
With uncemented prosthesis the bone is not fixed hard enough to the surface of the implant. A second operation for prosthesis revision is needed in both cases of endoprosthesis loosening.
As there aren’t ligaments to keep the components of the fixed endoprosthesis together, the patient has to be really careful during the first weeks after the operation. They should avoid positions of the lower limbs which could dislocate the endoprosthesis. In the course of time the organism will form enough connective tissue which will stabilize the newly fixed endoprosthesis.
Post-operative period
In the early post-operative period during the hospitalization, nurses, rehabilitation therapists and kinesitherapists take special care of the patient’s proper recovery.
Nurses
After the operation the nurses keep a close watch on the life indicators and status of the lower limbs of the patient and then record them in the patient’s file for the doctor in charge to read them. Antibiotics, which are to be taken every 6 or 8 hours a day, are often prescribed by the doctor with the purpose of decreasing the risk of infection.
The surgical wound is strictly watched on for:
-too much quantity of wound drainage;
-a proper initial healing process;
-need of a bandage change;
Rehabilitation therapist/ physiotherapist
In the early period after the operation of great importance are:
-patient’s training in secretion expectoration, as well as doing deep breathing exercises for prevention from complications such as pneumonia, and excretion of lung secretion, which has been produced during the operation;
-training in an up and down ankle movement-the patient has to do this 20 times an hour. This would be of help for normal blood circulation and thrombosis prevention;
-exercises for increasing the volume of mobility of the operated limb;
- exercises for improving the muscular strength of the limb. This would help the patient to be independent while walking, going up and down stairs, lying down and getting out of bed. This initial rehabilitation lasts about 5-7 days. At that time the patient may feel some discomfort and even pains. Pain pills are prescribed if necessary.
The rehabilitation therapist helps the patient take short distances walking on crutches or using a medical walker. This is important not only for increasing the volume of joint mobility and muscular strength, but also for attaining endurance.
The strain (stepping on the operated leg) depends on how well the prosthesis is fixed. With cement prosthesis fixation, stepping on the operated limb using walker may be allowed. With uncemented prosthesis ,the patient is forbidden to step on the operated limb for 4-6 weeks.
It is of great importance that the patient follows the doctor’s advice for non-weight bearing on his leg during the first weeks after the operation.
The patient has to be trained in doing his/her daily activities such as getting dressed, taking a bath, taking care of himself/herself after the operation.
The patient has to be trained in doing his/her daily activities while at the same time he/she has to keep away from not allowed excessive bending of the operated limb in the prosthesis.
Standard exercises used in the early period after endoprosthesis
The patient lies on his back, puts his legs and arms out straight to the body and starts bending his knee and hip joint while sliding the heel of the operated leg until he feels stretch in the operated region. This should be done until he counts to ten and then the normal position of the limb should be resumed.
Active abduction. The patient lies on his back and starts abducing the operated limb as much as he can while the big toe of the operated limb points the ceiling. Then the limb resumes its initial position again. The exercise should be done 2 sets daily, 20 times.
Quadriceps exercise. The patient lies on his back, puts his legs and arms out straight to the body and then starts contracting the quadriceps muscle while at the same time trying to push the knee towards the bed. The muscular contraction should last about 5-10 seconds, after which the patient takes a short rest. This is repeated 10-20 times for each limb. The exercise should be repeated several times an hour.
Final knee extension. The patient lies on his back, puts his legs and arms out straight to the body. There should be a pillow or cushion under his knee so that the knee is bent at an angle of 40 degrees. The patient starts contracting the quadriceps muscle and then raising the knee by lifting the heel from the bed. The muscular contraction should last 5-10 sec., after which the patient should slowly be laying down the heel to the bed. The exercise is repeated 10-20 times.
Gluteus exercise. The patient lies on his back, puts his legs and arms out straight to the body. Then he starts contracting the gluteus muscles and keeps the isometric contraction for 5 sec., after which takes a rest for another 5 sec. The exercise should be done 2 sets daily, 20 times.
Isometric abduction. The patient lies on his back, puts his legs and arms out straight to the body. A belt is put around the two limbs –a little above the knee joints. The patient starts trying to move his two legs apart against the resistance of the belt. This is done for 5 sec. and then the patient takes a rest for another 5 sec. The exercise should be done 2 sets daily, 20 times.
The patient has to follow the compulsory preventive measures after the operation:
Common rules that the patient has to obey after the operation:
During the first 6 to 8 weeks after the operation, the patient has to avoid bending the hip joint at more than 90 degrees. Because of this, the knees always have to be below the level of the hip joint while the patient is sitting down. Sitting on a small cushion, put on the chair, would be of help for the position mentioned above. The patient has to avoid sitting on low coaches, sofas, chairs and beds as this leads to excessive bending of the hip joints!
Also, avoid using the hip joint while bending in an attempt to reach the floor!
Do not cross the operated limb over the unoperated one (don’t sit with your legs crossed)!
While sitting always take a straddling position in a way that there is 15-20 centimetres distance between your knees!
The operated leg must not be rotated inwards!
When you go back home
Normally, patients with hip joint operation are discharged from hospital in 5 to 10 days after the operation, provided that there aren’t any complications and there is a member of the family who is going to take care of them at home.
The patient might be directed to a rehabilitation centre where he will be taken care of to the moment he feels able to take care of himself on his own and can go back home.
After coming back home the patient may be visited periodically by a rehabilitation therapist. Normally, 1 to 7 visits are enough. Home rehabilitation programme is similar to the hospital one- gradually the patient’s strength increases, the level to which he is able to move his limbs apart also increases, as well as the patient’s independence.
Walking
It is necessary that the patient uses crutches or a walker for a long time after hip joint prosthesis. The aim is, if possible, each patient gradually to become independent of using crutches or a walker, but unfortunately, this is not always totally achievable.
Gradually the patient’s increasing endurance will enable him to add new strengthening exercises to his programme such as going up and down stairs, standing on tiptoes.
What happens if the endoprosthesis is unsuccessful?
Endoprosthesis loosening is the most common reason for failure. If this happens, an operative revision of the artificial joint is needed. The scale of the revision operation depends on how complicated it would be to remove the artificial joint, as well as on the eventual need of follow-up recovery of the bone. A prosthesis revision operation is technically more complex than the operation for implantation. Also, every subsequent revision operation is more complex and harder than the previous one for both the surgeon and the patient.
Are there any alternatives of endoprosthesis?
Every patient who has been advised to undergo an endoprosthesis operation has to consider all the possible alternatives and discuss them with the general practitioner or the district orthopedist. Some alternatives of hip joint endoprosthesis are:
Medications. Anaesthetics and antiphlogistic medicine can often relieve pain to such an extent that the patient feels comfortable again. If this turns out to be possible and the volume of mobility remains the same, then it would be wise to put the operation off.
Corrective Osteotomy of femoral bone. In some cases of congenital dysplasia and some other conditions, it is possible to change the zone of strain through changing the femur axis, thanks to which the need of endoprosthesis is postponed for a while.
Arthrodesis. Arthrodesis is a surgical fusion of the femur head with the acetabulum with the goal of pain relief; thus, the mobility in the joint is eliminated. Today this operation is very rarely used.
What is the endoprosthesis lifetime?
The new materials used for the production of the contemporary endoprosthesis are extremely durable and most of them last over 10 years in 90% of the patients. There is 80% likelihood that the endoprosthesis lifetime will be 15 years.
How long after the endoprosthesis operation the patient will be able to walk without any help?
How long it will take the patients to learn to use crutches or a walker is very individual. Most of the patients need only 6 weeks to be able to walk using only a “Canadian type” crutches, but other patients need more time.
Driving
Patients who have undergone an endoprosthesis operation are not allowed to drive for at least 6 weeks.
How long after the operation the rehabilitation exercises that have already been trained should be done?
Patients have to do the exercises 2 times a day during the first 6 to 8 weeks after the operation. Afterwards, if the patient is in a condition to walk using only one crutch or even without any assisting devices, the exercises can be done 3 times a week with the purpose of keeping the muscular strength. As the periods of time for recovery are individual for each patient, this decision is taken by the orthopedist or the physiotherapist.
