Total Hip Replacement Surgery

What is a Hip Replacement (Hip Arthroplasty)?

Total hip replacement (THR) – also called total hip arthroplasty (THA) – is one of the most successful orthopaedic procedures performed worldwide today. This procedure involves the removal of the damaged sections of the hip joint and replacing them with artificial joints or prostheses to reduce pain and improve function.

In general, over 90 percent of THAs are working successfully, are pain-free, and are without complications for 10 to 15 years postoperatively. Some patients continue with their original implant even after 25 years of use.

What are the Benefits of a Hip Replacement?

Hip replacement is recommended for patients with hip pain due to medical conditions such as osteoarthritis, rheumatoid arthritis, and childhood hip problems. This surgery is considered a safe and effective procedure. Hip replacement surgery offers many benefits, such as:

• Pain relief
• Improved strength and mobility
• Long-lasting results
• Enhanced quality of life

What Conditions May Require Hip Replacement Surgery?

The normal hip functions as a "ball-and-socket" joint. The femoral head (ball) articulates with the acetabulum (socket), allowing a smooth range of motion in multiple planes. Any condition that affects either of these structures can lead to deterioration of the joint. This, in turn, can lead to deformity, pain, and loss of function. Hip pain has many causes.

Total hip replacement surgery may be a good solution to these conditions:

1. Osteoarthritis - wear and tear of the hip joint due to age-related degenerative change. It usually occurs in older patients and may have a genetic cause. Over time, the hip cartilage wears away, causing hip pain and stiffness. Patients may find it difficult to walk long distances, climb stairs and perform simple activities of daily living, such as putting on shoes and socks.

2. Avascular Necrosis - also known as AVN or ‘osteonecrosis’, is when the blood supply to the femoral head in the femur is damaged. This may cause the bone to die and the surface of the femoral head to collapse, leading to eventual degeneration of the joint and arthritis. Often, the cause of AVN is unknown (idiopathic) although sometimes the cause may be due to excessive steroid intake, often unwittingly through TCM, or due to excessive alcohol intake, certain diseases and even deep-sea diving.

3. Post-Traumatic Arthritis - This can follow a serious hip injury or fracture. The joint surface of the hip may become damaged and eventually, arthritis may occur over time.

4. Rheumatoid Arthritis - This is an autoimmune disease and one of the common types of a group of conditions called ‘Inflammatory Arthropathies’. The synovial membrane may become inflamed and lead to joint destruction over time. Typically, other joints of the body may be involved, and other organ systems may be affected. Patients may present at a younger age with this disease. Special blood tests may be required to diagnose inflammatory joint disease, and an orthopaedic surgeon often works closely with rheumatologists who may prescribe special drugs (DMARDs) to control the disease prior to the hip replacement surgery.

5. Childhood Hip Problems - such as Developmental Dysplasia of the Hip, congenital hip dislocation and Perthes Disease may lead to abnormal hip joint development and arthritis of the hip in later life.

6. Referred Spinal Pain - Spinal pain is commonly mistaken for hip pain. Spinal pain may involve back or buttock pain radiating down the back of the leg, sometimes associated with leg numbness or weakness. Hip pain often occurs in the anterior part of the groin and radiates down to the knee.

7. Hip Bursitis - The bursae are small, jelly-like sacs positioned between bones and soft tissues. They serve as cushions to help reduce friction during movement. Patients suffering from hip bursitis commonly experience joint pain, tenderness, and swelling.

8. Piriformis Syndrome - The piriformis is a flat, narrow muscle that supports the movement of the lower body. Piriformis syndrome occurs when the piriformis muscle compresses the sciatic nerve and causes inflammation.

Who Needs a Hip Replacement?

In some cases, orthopaedic specialists may initially recommend non-surgical treatments to manage symptoms of hip pain and stiffness. Some of these include pain relief medications, anti-inflammatory drugs, and physiotherapy.

However, patients may be advised to undergo a hip replacement if they experience the following:

1. Difficulty walking and performing daily activities due to debilitating hip pain
2. Severe hip pain even while at rest
3. Inability to get restful sleep due to the pain
4. Inability to move or lift their leg due to the stiffness
5. Symptoms that cannot be managed even after non-surgical treatment

Associated Risks and Complications

Hip replacement is considered a very safe and established procedure. Nonetheless, like all surgical procedures, there are risks involved; and your medical team will make every effort to keep it to a minimum and have contingency measures in place. These risks include:

1. Infection - An infection may occur in the wound or deep around the prosthesis. Minor infections can be treated with antibiotics. However, more serious infections may require another surgery or even the removal of the prosthesis, but this occurrence is very rare.

2. Blood Clots - Blood clots may develop in the leg veins in some cases. Orthopaedic surgeons will take preventive measures to minimise the risk of blood clots forming, such as the use of blood thinners, support hoses, and early mobilisation.

3. Dislocation - In the first few months after surgery, it is vital to avoid dislocating the hip while the tissues are still healing. You may be advised not to cross your legs or lie on the side of the replaced hip for the time being.

4. Unequal Leg Length - After hip replacement, some people may experience a slight discrepancy in leg lengths due to alterations in the anatomy of the hip joint. This can lead to a perception of unequal leg lengths, which is managed during the recovery and rehabilitation process.

5. Fractures - A periprosthetic hip fracture refers to a broken bone that has developed around the implant following a hip replacement. This is a serious and rare complication that is usually caused by a fall.

6. Nerve Damage - Nerve damage can happen in the area where the implant is placed and in some rare cases may cause numbness, weakness, and pain.

7. Implant Wear or Loosening - Hip prostheses may wear and loosen over time due to natural wear and tear. It may also result from the thinning of the bone or osteolysis. The risk is also higher among obese or overweight patients.

What are the Different Types of Hip Replacement Surgery?

The three major types are total hip replacement, partial hip replacement, and hip resurfacing. Other types of hip replacement surgery include the following.

1. Total Hip Replacement

   - Also called total hip arthroplasty, this is the most common type of hip replacement. In this procedure, both the ball and the socket are replaced with artificial implants. The socket is replaced with a durable plastic cup, while the femoral head will be removed and replaced with a ball made of ceramic or a metal alloy.

2. Partial Hip Replacement

   - Unlike total hip replacement, only the ball or the head of the femur is replaced in this procedure. The artificial replacement can be made of metal, plastic, or ceramic.

3. Hip Revision Surgery

   - This surgery is done to repair or replace an artificial hip joint to correct any damage caused by normal wear and tear, loosening of the implant, dislocation, or to fix alignment issues in the hip. Revision surgery may also be necessary to treat an infection or a broken bone around the artificial hip joint.

4. Hip Resurfacing

   - This procedure may be an alternative for hip replacement. In this procedure, the damaged cartilage and bone are trimmed off and capped with a smooth metal covering. However, hip resurfacing is only advisable for patients with strong, healthy bones.

5. Robotic Hip Replacement

   - Similar to a traditional hip replacement, this procedure involves the removal of damaged tissue in the hip and replacing it with an artificial joint. However, this procedure is performed with the assistance of a robotic arm. This method offers greater precision and requires a shorter recovery time.

What Happens Before a Hip Replacement Surgery?

Before a hip replacement surgery, patients undergo a comprehensive pre-operative evaluation including medical history, physical exams, and diagnostic tests. Other measures include guidance on medication adjustments, lifestyle modifications, and fasting before the procedure. On the day of surgery, patients meet the surgical team, anaesthesiologist, and nursing staff. Anaesthesia, which can be general or regional, is administered for patient comfort during the procedure.

What Happens During Total Hip Replacement Surgery?

In a Total Hip Replacement Surgery (also known as Total Hip Arthroplasty), the damaged cartilage and bone from the hip are removed and replaced with special implants.

The femoral head is removed and replaced with a metal stem that can be cemented into the shaft of the femur. For younger patients with good-quality bone, sometimes an uncemented stem is impacted into the femoral shaft. A metal or ceramic ball is placed on the metal stem to replace the femoral head. The worn cartilage of the hip socket (acetabulum) is removed and replaced with a metal shell. A plastic or ceramic liner is placed with this shell. This allows a smooth, low-friction articulation with the new femoral head.

Recovery Following Total Hip Replacement

Typically, hip replacement surgery takes around two hours, with several more hours of observation in the recovery ward before the patient is discharged to the general ward. Depending on the complexity of your procedure, you may be discharged to your home or to a rehabilitation unit for more physiotherapy, on or before Day 3 of surgery.

If you’ve been discharged on the same day, make sure you have someone accompanying you to drive you home. Meanwhile, if you’ve been sent for post-surgery rehabilitation, it is important that the physiotherapy instructions are followed carefully, in order to get the best out of the hip replacement surgery.

Normally, you are not allowed to travel in the first six weeks after the surgery. And depending on the nature of your work, you can return to work anytime around 6-12 weeks after surgery. This will of course still depend on the advice of your orthopaedic doctor.

Your surgeon may instruct you to refrain from doing certain movements that can dislocate your new hip, such as crossing your legs or bending your hips more than 90 degrees. In addition, you may be advised to avoid activities that incur great risks of falling and injury to prevent dislocation.

Moreover, if you will undergo dental procedures, make sure you inform your dentist about your hip replacement. Consult your surgeon first if you need to take antibiotics prior to dental procedures.

What Should I Look for in a Hip Replacement Surgeon?

It is vital to engage an accredited and experienced hip replacement surgeon to ensure a safe and effective procedure. Here are some important aspects to look out for:

1. Credentials - Ensure that the doctor is accredited as an orthopaedic surgeon, and experienced in their craft. You may assess their educational and training background, as well as past and present leadership positions and professional memberships.

2. Skills and Experience - Ensure your surgeon is experienced in the field (or subspecialty field) that you are interested in; as well as any unique skillsets they may have, such as robotic surgery or complex revision surgeries.

3. Good Communication & Demeanour - In order to foster a trusted and smooth patient journey, ensure that the doctor you choose makes you feel comfortable and confident in his or her care.