Osteoarthritis of the hip: symptoms, causes and what you should know

In this article, I explain the basics: how the hip joint works, what osteoarthritis is, and the symptoms my patients commonly experience.

The anatomy of the hip joint

The hip is a ball-and-socket joint.

• The ball is the rounded upper end of the thigh bone, called the femoral head
• The socket is a cup-shaped cavity in the pelvis called the acetabulum

The ball fits securely in the socket, allowing the hip to move in many different directions. This design keeps the hip stable while allowing a wide range of movement, including bending, straightening, rotating inward and outward, and moving the leg away from or toward the body.

Cartilage: the joint’s natural shock absorber

The ends of the bones in the joint are covered with cartilage, a smooth, slippery tissue that allows the bones to glide over each other without friction. Cartilage also acts as a shock absorber, helping the joint handle the forces created by walking, running and standing.

The hip is surrounded by strong muscles and ligaments that stabilise the joint and allow smooth movement.

Because the hip carries the body’s weight during daily activities, it is exposed to significant forces over a lifetime. Over time, these stresses can contribute to wear and damage within the joint.

Many of the long-term problems that affect the hip joint fall under the umbrella of arthritis conditions.

What is arthritis?

The word arthritis simply means inflammation or disease of a joint. There are many different types of arthritis, each with different causes.

In general, arthritis can be grouped into two broad categories:

Primary arthritis

Primary arthritis develops without a clearly identifiable underlying cause. It is thought to develop due to a combination of factors, including:

• Age-related changes in the joint
• Genetic or familial predisposition
• Long-term mechanical stress on the joint

The most common type of primary arthritis is osteoarthritis, which is discussed in more detail below.

Secondary arthritis

Secondary arthritis occurs because of another condition that damages the joint. Examples include:

• Previous injuries or fractures around the hip
• Inflammatory conditions such as rheumatoid arthritis
• Infections of the joint
• Congenital abnormalities where the joint did not form normally
• Certain metabolic or systemic diseases

What is osteoarthritis?

Osteoarthritis is the most common form of arthritis.

It is a joint disease that mainly affects cartilage – the smooth protective surface covering the ends of the bones.

Healthy cartilage allows the bones in a joint to move smoothly against each other. In osteoarthritis, the cartilage gradually becomes thinner and rougher. As it wears away, the bones beneath it can begin to rub together. This can lead to:

• Pain
• Swelling
• Stiffness
• Reduced movement in the joint

Over time, the joint may also change shape and bone spurs (called osteophytes) may develop along the edges of the joint.

Although cartilage damage is central to osteoarthritis, osteoarthritis affects the entire joint. Changes can occur in the bone beneath the cartilage, the joint lining, and the surrounding muscles and ligaments.

What is osteoarthritis of the hip?

Osteoarthritis can affect several joints in the body, including the knees, hands and spine. However, the hip is one of the joints most commonly affected.

When osteoarthritis affects the hip, the cartilage that normally cushions the ball-and-socket joint gradually deteriorates.

This process usually develops slowly over many years.

A helpful way to think about this is to imagine the tyres on your car. The tyre provides cushioning and allows the wheel to move smoothly along the road. Over time, tyres wear down and lose their ability to absorb shock.

Cartilage works in a similar way in the hip joint. As it thins and loses its smooth surface, the joint becomes less able to absorb load and move comfortably.

Eventually, the surfaces of the hip joint can become rough and irregular, which leads to pain and stiffness.

Osteoarthritis of the hip is very common, particularly as people get older, although it can also develop earlier in life after injuries or because of certain structural problems in the joint.

Signs and symptoms of hip osteoarthritis

Symptoms often develop gradually over months or years. Many patients initially notice mild discomfort in the hip or groin area that slowly becomes more noticeable.

People with hip osteoarthritis commonly experience some of the following symptoms:

Pain in the hip or groin: Pain is the most common symptom. It is usually a dull ache felt in the groin area, but it can also spread to the buttock, thigh or even the knee.

Stiffness: The hip may feel stiff, particularly in the morning or after sitting for a long time.

Pain with activity: Walking, climbing stairs, standing for long periods or bending forwards may aggravate the pain.

Reduced movement in the hip: Patients may notice difficulty putting on shoes or socks, getting in and out of a car, or bending down.

A limp while walking: Pain and reduced movement can cause people to change the way they walk.

Pain at night or difficulty sleeping: In more advanced cases, hip pain can interfere with sleep.

Some people also notice that symptoms worsen toward the end of the day after activity.

Who is more likely to develop hip osteoarthritis?

Several factors increase the likelihood of developing osteoarthritis of the hip. These include:

Age: Osteoarthritis becomes more common as people get older. It most often develops after the age of 45.

Previous injuries: Fractures, dislocations or sports injuries affecting the hip can increase the risk.

Joint shape or alignment problems: Some people are born with hips that are shaped slightly differently, which can place extra stress on the joint over time.

Family history: Genetics can play a role in the development of osteoarthritis.

Excess body weight: Carrying extra weight increases the load placed on the hip joint.

Certain occupations or activities: Jobs or sports that involve repetitive heavy lifting or high-impact movement can place additional strain on the joint.

The good news: hip osteoarthritis can be managed

Osteoarthritis of the hip is a common and treatable condition. Many people are able to remain active and independent for years with the right treatment and lifestyle adjustments.

While it can cause significant discomfort and limit mobility, effective treatments can help reduce pain and improve mobility.

In a future article, I will discuss:

• How osteoarthritis of the hip is diagnosed
• What tests and scans may be needed
• Treatment options, including both non-surgical and surgical approaches

If you are experiencing ongoing hip pain or stiffness and are concerned about it, speak to your orthopaedic surgeon or contact our practice for an assessment. I am always happy to evaluate your symptoms, identify the cause, and discuss the most appropriate way forward.

References

Sandiford N, Kendoff D, Muirhead-Allwood S. Osteoarthritis of the hip: aetiology, pathophysiology and current aspects of management. Annals of Joint. 2020.

National Institute of Arthritis and Musculoskeletal and Skin Diseases. Osteoarthritis.

Osteoarthritis Action Alliance. A Basic Overview of Osteoarthritis.

Versus Arthritis. Osteoarthritis of the hip factsheet.