What Is Hip Replacement Surgery?

Introduction

What is hip replacement surgery?

In hip replacement surgery, also known as hip arthroplasty, the diseased parts of the hip joint are surgically removed and replaced with new parts by an orthopaedic surgeon. These artificial parts mimic the movements of the normal hip joint. Typically, hip replacement surgery is required to restore hip joint injury caused by: 

• Osteoarthritis is a degenerative joint disease that has the potential to impact various joint tissues.
• Rheumatoid Arthritis -a chronic inflammatory condition that not only affects your joints but also affects numerous body systems, such as your skin, eyes, lungs, heart, and blood vessels, in certain individuals. 
• Osteonecrosis -  In osteonecrosis, the blood flow to a portion of the bone is disrupted. This causes the bone tissue to break down, leading to bone deterioration and joint collapse.
• Injuries or fractures caused by trauma or disease.¹   

Anatomy of the hip joint

Overview of the hip joint 

The axial skeleton is joined to the lower extremities through the hip joint. The hip joint facilitates motion along three principal axes, all of which are perpendicular to each other. The femoral head serves as the precise location of the centre of the entire axis. Through the transverse axis, flexion and extension are both possible.  

Vertically along the thighs, the longitudinal axis facilitates both internal and external rotation. Foreward or Backward motion is possible along the sagittal axis.² The hip is among the largest joints in the body. The hip joints are ball - and - socket joints. The socket is composed of the acetabulum, a component of the pelvis bone. The femoral head, the uppermost portion of the femur (thighbone), constitutes the ball.

Articular cartilage is a silky tissue that provides cushioning to the bone boundaries and facilitates, mobility, and covers the bone surface of the ball and socket. 

The synovial membrane, a thin tissue, envelops the hip joint. This membrane produces a minute quantity of fluid in a healthy hip, lubricating the cartilage and eliminating friction during hip movement.

Ligaments (the hip capsule) are bands of tissue that bind the ball to the socket and stabilise the joint.³ 

Functions of the hip joint

Your lower legs are connected to your torso (axial skeleton) through your hip joint. The function of your hip joint includes: 

• Providing support and equilibrium for your upper body
• Moving your upper leg
• Maintaining your body weight.⁴

What is the hip joint made of?

• Bones: Your hip joint connects your thigh and hip bones.
• Cartilage: Cartilage provides a seamless covering for the acetabulum socket and the femoral head at the apex of the thighbone. This material functions as a cushion that absorbs impact during walking and movement.
• Synovium: A synovium is a delicate covering that envelops the bones within a joint. It produces a lubricating fluid that enables the bones to move effortlessly and without resistance.
• Bursa: A bursa is a fluid-filled reservoir that provides the bones, muscles, and tendons in your joints with cushioning and a smooth surface to move on.
• Ligaments: Ligaments, specifically the femoral head to the acetabulum, are fibrous tissue bands that connect bones.
• Tendons: Tendons are fibrous tissue strands that establish a connection between the bones and muscles.
• Muscle: Large muscles in your hip provide joint support and mobility.⁴ 

Indications for hip replacement

Eligible candidates have moderate to severe hip arthritis that includes osteoarthritis, rheumatoid arthritis, or post-traumatic arthritis that causes discomfort and/or interferes with daily activities.

For instance:

• The task of climbing stairs and walking is challenging.
• Sleep may be disrupted by moderate to severe pain.
• Hip stiffness resulting from joint degeneration restricts the range of motion during daily activities.
• Non-surgical interventions, including physical therapy, steroid injections, non-steroidal anti-inflammatory medications (NSAIDS), and cane or walker usage, fail to sufficiently reduce the symptoms. 

Approximately 90% of hip replacement patients suffer from osteoarthritis. Hip replacement surgery is sometimes performed to treat fractured bones or other medical conditions, such as osteonecrosis, which is characterised by insufficient blood supply to the bone.⁵  

Pre-operative testing for hip replacement surgery

The scheduling of your preoperative testing will occur no later than 30 days before your scheduled surgery. A medical evaluation, blood samples, an electrocardiogram, a stress test, a chest X-ray, and a urine sample will comprise your testing. These examinations will determine whether your body is prepared for surgery or whether any conditions require special consideration before proceeding.  

Preparation for hip replacement surgery

• Before you go to the hospital, gather as much information as possible regarding the procedure. It is recommended that your hospital provides written materials or videos. 
• Maintain an active lifestyle. Increasing the strength of the muscles surrounding your hip will aid in your recovery. Continue light exercise, such as swimming and walking, if possible, in the weeks and months preceding your operation. 
• A physiotherapist, to whom you may be referred, will provide you with beneficial exercises.
• If you are a smoker, make an effort to reduce smoking.
• Make an effort to reduce your body weight if you are overweight. An increased risk of complications during or after surgery is associated with obesity.
• Arrange transportation to and from the surgical procedure and any subsequent appointments.
• Request household assistance for the first two weeks following your return from the hospital or surgical centre. This may involve assistance with laundry, cooking, and shopping.
• In advance, prepare for meals.¹ 

Types of Hip replacement surgeries

Total hip replacement

Upon hearing the term “hip replacement”, this particular procedure typically comes to mind. A total hip replacement involves the removal of the damaged joint’s ball and socket, followed by their substitution with prosthetic components made from ceramic, metal, or plastic. It can be performed by an anterior approach through the front of the leg, or a posterior approach which is a minimally invasive incision through the back of the joint.

Partial hip replacement

Partial hip replacement, also known as hemiarthroplasty, involves the replacement of solely the ball of the hip joint while leaving the socket. Its main use is to treat fractures and other traumatic hip injuries in which the ball is fractured.

The utilisation of partial hip replacement for degenerative conditions where both parts of the joints have been damaged is not common. A partial hip replacement is an uncommon procedure and is typically performed on elderly patients who have suffered a hip fracture and are unable to undergo a total hip replacement. 

Hip resurfacing

A hip resurfacing procedure involves the preservation of the original joint and is covered with a thin sheet of metal. Merely a few centimetres of bones are extracted, sufficient to guarantee a thigh fit with the metal. There is a reduced likelihood of dislocation, and patients may be able to resume more vigorous physical activity once the procedure is complete, as a significant portion of the initial bone is retained.

What to expect during hip replacement surgery?

The patient will be administered anaesthesia. You may experience the following, depending on your health and current medications, prior anaesthetic experiences, and the type of hip replacement you are undergoing : 

• Through the use of regional anaesthesia, nerves to a specific area of the body are blocked. Most patients undergoing regional anaesthesia would be awake, so you may be administered a moderate sedative to induce relaxation.
• General anaesthesia induces sleepiness throughout the entire body by influencing the brain and nervous system.
• An incision will be made by your surgeon over the hip. Many variables will affect the extent of the incision including your body proportions, the specifics of your joint problem, and the preferences of your surgeon.
• The afflicted cartilage and bone tissue will be surgically removed from the hip joint. Your surgeon will substitute the ball ( head of the femur) and the surface of the socket (acetabulum) with artificial parts.
• You will be transferred to the recovery room following surgery.¹

Risks and complications

• Loosening of the joint
• Hip dislocation
• Altered leg length
• Infection
• Blood clots
• Fracture
• Nerve Damage

FAQs

What exactly happens in hip replacement surgery?

The surgeon makes an incision over the thigh and removes the diseased or damaged cartilage and bone from the hip joint during a hip replacement. Following this, the surgeon substitutes the acetabulum and tip of the femur with artificial components.¹

Is a hip replacement a major operation?

As hip replacement surgery is a major surgery, it is typically prescribed only when alternative therapies, including steroid injections or physiotherapy, have proven ineffective in reducing pain or enhancing mobility.

How serious is hip replacement surgery?

Total hip replacement surgery is a major surgery. It is extremely safe, but there are potential risks associated with every surgery. A hip replacement carries the risk of dislocation of the hip or blood clotting in the pelvis or limb. However, the most significant risk is contracting an infection.

How long does it take to recover from a hip replacement?

If you have a job requiring less physical activity such as a desk job then you can return to work after 2 weeks.  It is advisable to take approximately six weeks off to rehabilitate if your occupation involves heavy lifting. 

Summary

In hip replacement surgery, the diseased parts of the hip joint are surgically removed and replaced with new parts by an orthopaedic surgeon. Hip replacement surgery is required to restore hip injury caused by osteoarthritis, rheumatoid arthritis, osteonecrosis, injuries, or fractures.  The functions of the Hip joint include providing support and equilibrium to your upper body, moving your upper leg, and maintaining your body weight. 

The hip joints are made up of Bones, Cartilage, Synovium, Bursa, Ligaments, Tendons, and Muscles. A medical evaluation, blood samples, an electrocardiogram, a stress test, a chest X-ray, and a urine sample will comprise your testing. These examinations will determine whether any conditions require special consideration before proceeding. 

Types of Hip Replacement Surgeries include Total Hip Replacement, Partial Hip Replacement, and Hip Resurfacing. Risks and complications of hip replacement surgery include loosening of the joint, hip dislocation, altered leg length, infection, blood clots, fracture, and nerve damage.