Total Hip Replacement (THR)

Primary and Complex Total Hip Replacement

Introduction

Hip replacement has become necessary for your arthritic hip: this is one of the most effective operations known and should give you many years of freedom from pain.

Once you have arthritis which has not responded to conservative treatment, you may well be a candidate for Total Hip Replacement surgery.

Arthritis

Arthritis is a general term covering numerous conditions where the joint surface (cartilage) wears out. The joint surface is covered by a smooth articular surface that allows pain free movement in the joint. This surface can wear out for a number of reasons, often the definite cause is not known. When the articular cartilage wears out, the bone ends rub on one another and cause pain. There are numerous conditions that can cause arthritis and often the exact cause is never known. In general, but not always, it affects people as they get older (Osteoarthritis).

Other Causes Include

• Childhood disorders e.g., dislocated hip, Perthe’s disease, slipped epiphysis etc.
• Growth abnormalities of the hip (such as a shallow socket) may lead to premature arthritis
• Trauma (fracture)
• Increased stress e.g., overuse, overweight, etc.
• Avascular necrosis (loss of blood supply)
• Infection
• Connective tissue disorders
• Inactive lifestyle- e.g., Obesity, as additional weight puts extra force through your joints which can lead to arthritis over a period of time
• Inflammation e.g., Rheumatoid arthritis

Diagnosis

The diagnosis of osteoarthritis is made on history, physical examination X-rays. There is no blood test to diagnose Osteoarthritis (wear tear arthritis)

Indications

THR is indicated for arthritis of the hip that has failed to respond to conservative (non-operative) treatment.

You should consider a THR when you have

• Arthritis confirmed on X-ray
• Pain not responding to analgesics or anti-inflammatories
• Limitations of activities of daily living including your leisure activities, sport or work
• Pain keeping you awake at night
• Stiffness in the hip making mobility difficult

Benefits

Prior to surgery you will usually have tried some simple treatments such as simple analgesics, weight loss, anti-inflammatory medications, modification of your activities, walking sticks, physiotherapy.

The decision to proceed with THR surgery is a cooperative one between you, your surgeon and your family . Benefits of surgery include

• Reduced hip pain
• Increased mobility and movement
• Correction of deformity
• Equalization of leg length (not guaranteed)
• Increased leg strength
• Improved quality of life, ability to return to normal activities
• Enables you to sleep without pain

Surgical Procedure

An incision is made over the hip to expose the hip joint

The acetabulum (socket) is prepared using a special instrument called a reamer. The acetabular component is then inserted into the socket. This is sometimes reinforced with screws or occasionally cemented. A liner which can be made of plastic, metal or ceramic material is then placed inside the acetabular component.

The femur (thigh bone) is then prepared. The femoral head which is arthritic is cut off and the bone prepared using special instruments, to exactly fit the new metal femoral component. The femoral component is then inserted into the femur. This may be press fit relying on bone to grow into it or cemented depending on a number of factors such as bone quality and surgeon’s preference.

The real femoral head component is then placed on the femoral stem. This can be made of metal or ceramic. The hip is then reduced again.

The muscles and soft tissues are then closed carefully.

Post-op precautions

Avoid the combined movement of bending of your hip turning your foot in. This can cause Dislocation. Other precautions to avoid dislocation are ( at least for the first 6-9 months)

• You should sleep with a pillow between your legs for 6 weeks. Avoid crossing your legs and bending your hip past a right angle
• Avoid low chairs
• Avoid bending over to pick things up. Grabbers are helpful as are shoe horns or slip on shoes
• Elevated toilet seat helpful

Risks and Complications

As with any major surgery, there are potential risks involved. The decision to proceed with the surgery is made because the advantages of surgery outweigh the potential disadvantages.

It is important that you are informed of these risks before the surgery takes place.

Complications can be medical (general) or specific to the Hip

Medical Complications

Include those of the anesthetic and your general well being. Almost any medical condition can occur so this list is not complete.

Complications include

Allergic reactions to medications

Blood loss requiring transfusion with its low risk of disease transmission

Heart attacks, strokes, kidney failure, pneumonia, bladder infections

Complications from nerve blocks such as infection or nerve damage Serious medical problems

Specific complications

Infection

Infection can occur with any operation. In the hip this can be superficial or deep. Infection rates are approximately 1%, if it occurs it can be treated with antibiotics but may require further surgery. Very rarely your hip may need to be removed to eradicate infection.

Dislocation

This means the hip comes out of its socket. Precautions need to be taken with your new hip. It a dislocation occurs it needs to be put back into place with an anesthetic. Rarely this becomes a recurrent problem needing further surgery.

Blood clots (Deep Venous Thrombosis)

These can form in the calf muscles and can travel to the lung (Pulmonary embolism). These can occasionally be serious and even life threatening. If you get calf pain or shortness of breath at any stage, you should notify your surgeon.

Damage to nerves or blood vessels

Also rare but can lead to weakness and loss of sensation in part of the leg. Damage to blood vessels may require further surgery if bleeding is ongoing.

Wound irritation

Your scar can be sensitive or have a surrounding area of numbness. This normally decreases over time and does not lead to any problems with your new joint.

Leg length inequality

It is very difficult to make the leg exactly the same length as the other one. Occasionally the leg is deliberately lengthened to make the hip stable during surgery. There are some occasions when it is simply not possible to match the leg lengths. All leg length inequalities can be treated by a simple shoe raise on the shorter side.

Wear

All joints eventually wear out. In general 80-90% of hip replacements survive 20-25 years.

Failure to relieve pain

Very rare but may occur especially if some pain is coming from other areas such as the spine.

Unsightly or thickened scar

Limp due to muscle weakness

Fractures (break) of the femur (thigh bone) or pelvis (hipbone)

This is also rare but can occur during or after surgery. This may prolong your recovery, or require further surgery.

Summary

Surgery for some people with arthritis, could mean the difference between leading a normal life or putting up with a debilitating condition. Surgery can be regarded as part of your treatment plan- it may help to restore function to your damaged joints as well as relieve pain.