Total Hip Replacement (THR), also called Total Hip Arthroplasty (THA), was first performed in 1960 in UK. Since then, there have been tremendous improvisations in implant design and surgical techniques. This surgery has revolutionized the treatment of severe hip arthritis, and is one of the most significant medical achievements of the twentieth century. The first Total Hip Replacement in India was performed in Mumbai by Dr K T Dholakia in April 1972. THR is now performed routinely at various super-specialty centers in India at Mumbai, Pune, Chennai and New Delhi. Before understanding the basic concepts of THR, we must know the anatomy of the hip joint.
The hip joint is formed by two bones – the acetabulum and the femoral head. The acetabulum is cup-shaped (hemispherical) and is a part of the pelvis. Its diameter usually varies between 40 mm to 60 mm. The spherical femoral head is the uppermost part of the femur (thigh bone), and is located within the hemispherical cavity of the acetabulum. The femoral head moves quite freely in all directions within the confines of the acetabulum. Thus, the hip joint is a ball-and-socket joint.
Both the femoral head (ball) and the acetabulum (socket) are replaced in THR.
The socket is replaced with a metallic or plastic cup (shell) which is fixed to the pelvic bone. A liner made of plastic, ceramic or metal is then fixed into the cup. This completes the acetabular part of the operation.
On the femoral (thigh bone) side a metallic stem is securely inserted into the bony canal. The stem has a neck, onto which a metallic or ceramic head is fixed.
This head articulates or couples perfectly with the liner in the acetabular cup, thus recreating a ball-and-socket joint.
(a) Cemented Total Hip Replacement: Both the cup (acetabular socket) and the stem components are fitted into the bone with a special material called acrylic bone cement (see figure on the right).
(b) Uncemented Total Hip Replacement: Both the cup (acetabular socket) and the stem components are fitted into the bone without using acrylic bone cement (see figures on the left and below). The surfaces which come into contact with the bones are specially prepared using sintered titanium or hydroxyapatite coating, which allows bone ingrowth into the components. Thus the implant becomes a ‘part of host-bone’. The figure below shows bone ingrowth into an uncemented cup which was removed in revision surgery.
(c) Hip Resurfaing: The surface of the damaged femoral head is shaved off and replaced (re-surfaced) with a new surface. This is a bone preserving operation because the entire femoral head is not sacrificed. In selected cases, this procedure may allow a faster recovery and much better range of movement after the surgery.
(d) Bipolar Hip Arthroplasty: Here the acetabular component is not fixed into the acetabular cavity, but moves within it, and couples with a snap-fit with the femoral head. This is an excellent option for elderly patients with a femur neck fracture.
The choice of the above options is based on patient factors and surgeon preference. All of the above procedures have extremely good results.
You may need hip replacement surgery in the following situations:
The patient should be convinced that he or she needs a THR surgery and that no other option is suitable (see section: Who needs total hip replacement surgery). Before taking the final decision, the patient must be aware of the benefits and the potential risks of THR surgery.
All surgeons take utmost care to prevent infection after a THR surgery.
The operation theatre is spacious, and is equipped with a laminar air-flow system for clean air.
Disposable body-exhaust suits (colloquially called space-suits) are used by the surgical team to minimise infection. Meticulous aseptic precautions are taken before, during and after the surgery.
Antibiotics are used prophylactically to combat any possible chance of infection.
The risk of infection is low (less than 1%), but it cannot be ignored.
2. Venous Thromboembolism or VTE – This means formation of blood clots in the leg veins of the patient, which can possibly migrate to the heart and lungs. This problem is prevented by giving blood-thinners for a few days after the surgery, and also by an exercise program to maintain blood circulation in the leg in the post-operative period.
3. Complications due to medical illnesses like heart disease, hypertension, diabetes, allergies and asthma can occur, but with present-day medical care, this risk is also very low.
4. Extremely rare complications are
Once it is decided that you are going ahead with the surgery, you will have a complete medical assessment before your surgery. This is required to detect any problems preoperatively which may adversely affect your recovery. Any abnormalities such as high blood pressure, low haemoglobin, diabetes, heart disease or asthma are managed medically in the appropriate manner. It is advisable not to smoke for 3 – 4 weeks before the surgery.
Blood tests, Urine examination, Chest X-ray, ECG and 2D Echo are done routinely. Some patients may require further tests.
Any skin lesions are treated to prevent infection spreading to the hip joint after surgery.
Bacteria can enter the bloodstream during dental procedures like tooth extractions and root canal treatment. Hence, such procedures, if required, must be done well in advance of a THR surgery.
Urinary tract infection can spread through bloodstream to the hip joint after THR. Hence, it should be treated adequately. A routine urine test will be usually sufficient to detect urinary tract infection.
Infection in the chest (upper or lower respiratory tract infection – URTI or LRTI) can also spread through bloodstream to the hip joint after THR. Hence, it has to be treated completely.
You will be admitted to the hospital one day before the surgery. You must be sure to bring with you all the investigation reports and X-Rays. After admission, you will be jointly assessed by your surgeon and a member of the anaesthesia team. Generally you would require overnight starvation if the surgery is scheduled for the next morning
The surgery lasts for about 2 hours. However, it can take longer in certain circumstances. Also, adequate time is needed for preparation and anaesthesia induction before the actual surgery. Thus, the patient may be in the operation theatre for almost 4 hours.
After the implant is inserted in the body, it is confirmed that the hip joint is stable and has full range of motion, and that the leg lengths are equal.
After surgery, you will be moved to the recovery room where you will remain for about two hours till you fully recover from anaesthesia. After you awaken fully, you will be taken to your hospital room. In some cases, for additional safety, you may be moved into an ICU for 24 hours.
You will stay in the hospital for 4 to 5 days. After surgery, you will feel pain in the hip. This is no different and no more than any other surgical procedure. The pain usually lasts for 2 -3 days and round-the-clock pain medication will be given to make you comfortable. Also, other medications like antibiotics and blood-thinners will be given as required.
You will be encouraged to stand and walk 24 – 48 hours after your surgery, with the aid of a walker. A physiotherapist will supervise your exercise program in the hospital.
The surgery lasts for about 2 hours. However, it can take longer in certain circumstances. Also, adequate time is needed for preparation and anaesthesia induction before the actual surgery. Thus, the patient may be in the operation theatre for almost 4 hours.
After discharge from the hospital, you will be taking care of yourself with the help of relatives. Of course, your doctor and physiotherapist are just a phone call away. You must ensure that you have understood the doctor’s instructions at the time of discharge from the hospital. Please bear in mind that the success of your surgery will be largely dependent on how well you follow these instructions.
Diet :
A balanced diet with iron, calcium and mineral supplement is advised. Good fluid and water intake is a must. Some loss of appetite may be experienced for a few days after surgery, and some patients have constipation for 2 – 3 days.
Wound Care:
The surgical wound is closed with stitches or staples, which will be removed about two weeks after surgery. Till that time, the wound should not get wet. The dressing over the wound must remain intact. After suture / staple removal, the surgical area may be bathed normally, as the wound is healed.
Medications:
You will be prescribed antibiotics and pain-killers for a few days. In addition, you may need specific medication for conditions like diabetes, heart disease and hypertension. Blood-thinners are also required for the prescribed period to prevent venous thromboembolism.
Activities and exercise:
You must meticulously follow instructions from your doctor and your physiotherapist about your exercise program after the surgery. Physiotherapy is important to maintain muscle strength and joint mobility, and also to prevent complications like venous thromboembolism. The physiotherapist will guide you how to walk at home with a walker. He or she will instruct you regarding how to attend to your personal hygiene. Later, you will be asked to climb up and down the stairs. Gradually, you will be weaned off from your walker to a handy walking stick, and thereafter to independent ambulation.
1. In order to prevent dislocation and to avoid putting excessive loads on the artificial hip joint in your body
2. Prevention of blood clots in the leg veins – You will be put on an exercise program and a course of blood-thinners. But you must remain vigilant about possible warning signs about blood clots, and inform the doctor immediately. Warning signs of possible blood clots are: pain, tenderness, swelling or redness in the calf and leg. If the blood clot has migrated to the lung, there may be discomfort in breathing or chest pain.
3. Prevention of infection – Infection is prevented with antibiotics. But if infection does occur and is detected early, it is relatively easy to treat. Warning signs of a possible infection after THR are: redness, tenderness or swelling of the hip wound or persistent fever (> 1000 F).
