Hip replacement, Types, indications, contraindications, surgery and Complications

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Hip replacement is a type of surgery in which part or whole of the diseased natural hip joint is replaced with artificial components.

Before reading on it would be a good idea to learn about the hip anatomy. Skip this if you have already done so.

Hip replacement surgery can be classified into different types. On the basis of number of components being replaced it can be

Partial, in which only the femoral component is replacedTotal, in which the femoral and the acetabular components are replaced

Total hip replacement can be of two types

Classical total hip in which the neck and head of the femur are removedArticular surface replacement or ASR in which neck is preserved and a artificial head is implanted on it

On the basis of the material used in the components it can be

polyethylene on metal meaning that the acetabulum is of polyethylene and the head is of metalmetal on metal meaning both components are of metalceramic on ceramic meaning both components are of ceramic

Sometimes cement is used to hold the components within the bone. So depending upon the use of cement or not it can be

cemented in which cement is usedUncemented in which no cement is used to anchor the components

So we can have a polyethylene on metal cemented or uncemented type of hip replacement or a partial cemented or uncemented replacement. All this depends upon the requirement of the patient under going surgery.

Cemented prosthesis is usually used for older patients who have a life expectancy of 20 years and are unlikely to require revision surgery. The function of cement is to act as a filler in between the bone and the prosthesis there by providing a stable fixation.

Metal on metal, ceramic on ceramic and uncemented prosthesis are indicated for young and active people. These prosthesis conserve bone and are designed to allow bone to grow and develop an intimate contact with the prosthesis. This increases the stability and longevity of the implant.
Revision surgery is easier in these patients, as the patient has good bone stock for the surgeon to work on.

This is a x ray of a cemented hip replacement. You can see the cement layer around the implant.

This is a x ray of a uncemented hip. Screws have been used to fix the acetabular component.

The only indication of total hip replacement surgery is painful osteoarthritis of the hip joint. The cause of the osteoarthritis can be manifold. Such as avascular necrosis, rheumatoid arthritis, ankylosing spondylitis, trauma, infections etc. All these conditions can eventually lead to the development of hip osteoarthritis. The diseases or conditions can be different but the end result is the same ie, osteoarthritis.

The only indication of a partial hip replacement is a fracture neck femur in a elderly person. This person has a life expectancy of 5 to 10 years and is required to move around in her/his house

Contraindications for hip replacement include the following

Infection in or around the hip joint such as an anal fistula or urinary tract infection.A well functioning painless arthrodesis (a condition in which the hip joint is fused eliminating all movement) of the hip joint.A well functioning painless excision arthroplasty (a condition in which due to tuberculosis, infection or a late presenting fracture neck femur the head and neck of the femur are surgically removed and the patient is put on vigorous physiotherapy so that a pseudo joint is formed between the pelvis and remaining part of the upper end of the femur) of the hip joint.Uncontrolled diabetes mellitus, heart disease, lung disease, neurological disease, vascular disease and other systemic diseases that make the surgery very risky for the life of the patient.

Before under going hip replacement surgery your doctor will see and document the following things

he will assess the amount of disability by asking about day to day activities including activities that require squatting or sitting cross leggedthe requirement of a walking aidexamine the hip for stability, pain, range of motion and amount of shortening of the limblook for any previous surgery around the hipmeasure the degree of movement in the hip joint and the presence of deformitieshe will exclude other causes of pain such as arthritis of the sacroiliac joint and spine and pain due to vascular or neurological causeswill look for muscular weakness, sensory loss and palpate the pulses in the limbask about the presence of any systemic disease such as diabetes mellitus, hypertension, liver disease etcinquire about any addiction such as smoking or alcoholism

Investigations that will be under taken before hip replacement include the following

Complete blood countrenal function testsliver function testsurine analysisassessment of cardiac and respiratory function by a specialist or through testsassessment of bone mineral density for osteoporosisx rays of both the lower limbs in standing position from the hip to the ankle joint, taken in two planesA CT scan or MRI of the hip may also be required

After all the investigations are complete the surgeon will plan the hip replacement surgery. The planning can be done over the radio-graphs of the patient or by taking their tracings. Now templates of the implant are used to determine which size of the implant will be required and how much the bone has to be cut.

Anesthesia used is of two types

General anesthesiaRegional anesthesia

The choice of anesthesia depends on the patient, the surgeon and the anesthesiologist. Regional epidural anesthesia is preferable because it can provide pain relief for up to 2 hours before surgery. This results in less use of morphine based drugs for post-operative pain control.

After anesthesia the patient may be turned and placed on his side or may continue to lie straight. It depends on which position the surgeon is comfortable with. A brief description of the surgery is given below.

A incision is applied on the side of the upper part of the thigh centered over the greater trochanter of femur. After the skin and subcutaneous tissue have been cut a sheet of tissue is exposed that is the fascia lata.This is then cut in the middle longitudinally.This exposes the greater trochanter of the femur along with its various muscular attachments.At this juncture the surgeon has two choices. He can either expose the hip joint by cutting the anterior capsule in front or by cutting the posterior capsule behind.If he goes in front then he has to tag and cut part of the tendon of the gluteus medius muscle.If he goes behind then he has to tag and cut the external rotator muscle tendons.After the capsule has been cut the hip joint is dislocatedNow the arthritic head of the femur and the acetabulum can be visualized.The bone spurs and dead bone is removed from the head and acetabulum.Either the acetabulum or the femur can be prepared first.The acetabulum is prepared by by removing the cartilage and bone tissue till a bed of bleeding bone is obtained.After the acetabulum has been prepared it is packed with a sterile mop.Now the femur is prepared by cutting the neck at a predetermined level and removing bone from the neck and the upper femoral canal with a special instrument called a reamer or rasp. This creates a cavity that mimics the shape of the femoral stem of the prosthesis.Every implant manufacturer provides trial components which are duplicates of the original implant that is to be inserted. These trial components are now inserted in the bone. The hip is relocated and stability and range of motion is assessed. If the surgeon is not satisfied then the trail components are changed till a satisfactory size is obtained.Now the final implants of correct size are removed from their sterile packs and implanted into the prepared femur and acetabulum with or without cement depending on the type of prosthesis being implanted.A final check of stability and movement is done.Drains are inserted to remove collected blood and tissue fluid.The incision is closed in layers beginning with the capsule, then muscles and tendons, then fascia lata and finally the subcutaneous tissue and skin.

Now the operated person is shifted to a post-operative care ward. Vital signs are monitored and kept stable. Here he or she is kept for 24 hours. The drain is removed after 24 to 36 hours.

Movement of the limb is started. Exercises of the hip and knee are encouraged. Walking with or without support is usually allowed from the third or fourth day.

Complications can be of two types

Immediate complicationsThromboembolismInfectionNerve injuryFracture of femur boneLate complicationsDislocation of the hipLoosening of the implant

Thromboembolism is the formation of blood clots in the veins of the lower limbs and their subsequent dislodgement, migration with blood and obstruction of the pulmonary arteries that take blood to the lungs. This is a potential fatal complication with a reported incidence of 0.1 to 1%. It is more frequently seen in the following conditions

female sexage above 40 yearsobesitydiabetes mellitussmokingvascular heart diseaseprevious thrombosis episodes

Many methods are used to prevent this complication which include

compression stockingsfoot pumpsanti-coagulant drugs such as low dose warfarin, low molecular weight heparin and aspirin

Infection is another important complication that can occur. The incidence is less than 1%. Infection can be prevented by Good cleaning and disinfection of the operation theater with the use of formalin fumigation, UV light and vertical laminar air flow.Keeping the operation theater personnel as minimum as possible and preventing their movement in and out of the theater.Using prophylactic antibiotics.Fast and precise surgical technique

More chances of infection are present in persons who have the following conditions

Diabetes MellitusLow grade persistent infection such as ear infection or urinary infectionPrevious surgery on the hip jointObesityRenal failureCancerSkin diseases such psoriasisare Smokers

Nerve injury can occur following hip replacement. It is usually the results from excessive retraction or wrong placement of a tissue retractor.

Fracture of the femur can also occur. This is seen if the bone is damaged during surgery and in osteoporosis. This is very rare.

Dislocation of the hip can by trauma or by trying extremes of movement early after the surgery. It is more common when the surgical approach is from behind the hip joint.

Loosening of the implant is seen in 5 to 10% of hip replacements after 15 to 20 years. It occurs due to the absorption of the bone around the artificial hip. The cause of this loosening is not clear but it is thought to occur from the release of plastic debris from the acetabular component of the artificial hip.

There have also been instances of loosening of the artificial hip, dislocations and pain due to faulty implants. These have resulted in earlier than expected revision surgeries. If you have these problems then you can click here to know more.

Treatment of loosening is by revision surgery with bone grafting and use of hip implants which promote in-growth of bone around them.

How long does if take to fully recover from hip replacement surgery?

Full recovery can take 3 to 6 months. Physiotherapy is essential for full recovery.

What can be done to enhance the life of the artificial hip?

Best way to increase the longevity of the artificial hip is to minimize the intensity of load that acts across it by

reduce weight if you are over weight or obeseavoid excessive jumping, running, squatting and climbing too many stairsprevent or treat osteoporosis

I hope the information provided was useful. If you have any query you can ask me at the contact me page.

This page was updated on 22th April 2011.

Causes of hip pain...

Hip osteoarthritis

Avascular Necrosis of Hip

Hip Fracture

Perthes Disease

Congenital Dislocation of Hip

Hip Anatomy

Go back to Hip Pain from Hip Replacement

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