Hip Osteoarthritis
Hip osteoarthritis is a condition in which the smooth cartilage covering the surfaces of the hip joint becomes damaged or worn, leading to pain, stiffness and reduced movement. The most common form is osteoarthritis, which typically develops gradually over time and may cause groin or thigh pain, difficulty walking, reduced hip flexibility and problems with everyday activities such as putting on shoes and socks. As arthritis progresses, X-rays may show narrowing of the joint space, changes in the underlying bone and the formation of bone spurs (osteophytes). Treatment depends on the severity of symptoms and can range from exercise, physiotherapy, medications and injections through to hip replacement surgery when symptoms significantly affect quality of life.
Introduction
Hip arthritis is one of the most common causes of hip pain, particularly as we get older.
It can start with something quite subtle — perhaps a little stiffness when you first get up in the morning, difficulty putting on your shoes and socks, or an ache in the groin after a long walk.
Over time, however, hip arthritis can begin to interfere with walking, exercise, sleep and normal day-to-day activities.
What is hip arthritis?
The hip is a ball-and-socket joint.
The ball is formed by the head of the femur, or thigh bone, and this sits within a socket in the pelvis called the acetabulum.
In a healthy hip, both of these surfaces are covered by a very smooth layer of articular cartilage.
That cartilage allows the joint to move smoothly with very little friction and also helps distribute the forces that pass through the hip when we walk, run and exercise.
In osteoarthritis, that cartilage gradually becomes damaged and worn.
As the cartilage deteriorates, the space between the ball and socket becomes narrower.
The bone underneath the cartilage also begins to respond. It can become thicker and harder — something we call subchondral sclerosis — and small cysts can sometimes develop within the bone.
The body can also form additional bone around the edges of the joint. These are called osteophytes, or bone spurs.
As these changes progress, the hip can become increasingly stiff and painful.
What causes hip arthritis?
For many people, there isn’t one single cause.
Age is certainly an important factor, but osteoarthritis isn’t simply an inevitable consequence of getting older.
Genetics can play a role, as can previous injuries to the hip.
The underlying shape of the hip is also important.
Some people are born with a relatively shallow hip socket, known as hip dysplasia, which changes the way forces are distributed across the joint.
Other people may have a shape of the femoral head or neck that causes femoroacetabular impingement, or FAI.
Over many years, these abnormalities can contribute to damage to the cartilage and eventually the development of arthritis.
Previous fractures, childhood hip conditions and other diseases affecting the hip can also lead to what we call secondary osteoarthritis.
What does hip arthritis feel like?
The classic symptom of hip arthritis is pain in the groin.
That surprises some patients because they expect hip pain to be felt on the outside of the hip.
The pain can also travel down the front of the thigh and occasionally all the way to the knee.
Some patients actually present initially with what they think is knee pain, when the problem is coming from their hip.
Pain isn’t the only symptom.
Stiffness is extremely common.
You may notice that you’re having difficulty putting on your shoes and socks, cutting your toenails, getting into or out of the car, or getting up from a low chair.
You may find that your walking distance gradually becomes shorter.
Activities that were previously easy — walking the dog, playing golf, exercising or travelling — may become increasingly difficult.
As the arthritis becomes more advanced, people may develop a limp.
Pain may occur with relatively short periods of walking and, in more severe cases, can occur when you’re sitting or resting.
Night pain can be particularly troublesome and is often one of the symptoms that eventually prompts people to seek treatment.
How do we diagnose hip arthritis?
Diagnosis usually starts with listening carefully to your symptoms.
Where is the pain?
How long have you had it?
What activities bring it on?
How far can you walk?
Does it interfere with work, exercise or sleep?
I’ll then examine the hip.
I’m particularly interested in your range of movement, where you experience pain, how you walk and whether some of your symptoms could actually be coming from somewhere else — particularly the lower back.
For most patients, the most useful investigation is actually quite simple:
a plain X-ray.
Ideally, this includes a standing X-ray of the pelvis and hip.
On the X-ray, we’re looking for several characteristic changes.
The first is loss of joint space. Because cartilage doesn’t show directly on an X-ray, the space between the bones gives us an indication of how much cartilage remains.
We also look for osteophytes, or bone spurs, thickening of the bone underneath the joint surface, cyst formation and changes in the shape of the femoral head and socket.
In most cases, an X-ray combined with the history and examination gives us the diagnosis.
Occasionally, we may use an MRI or CT scan if the diagnosis isn’t clear or if we’re looking for another problem within the hip. CT may also be used to plan any surgery
Does arthritis on an X-ray mean I need a hip replacement?
No.
And this is an important point.
We don’t treat an X-ray.
We treat the person.
Some patients can have quite significant arthritis on an X-ray but relatively manageable symptoms.
Others may have extremely limiting pain and stiffness.
The decision about treatment therefore depends on how much the arthritis is affecting your life, rather than simply how impressive the X-ray looks.
Can hip arthritis be treated without surgery?
Absolutely.
There are several treatments we can use before considering surgery.
One of the most important is maintaining activity.
People sometimes worry that exercise is going to wear their hip out more quickly. In most circumstances, becoming completely inactive is actually counterproductive.
Low-impact activities such as cycling, swimming and walking within comfortable limits can be very useful.
Strengthening the muscles around the hip can also help maintain function and reduce symptoms.
A physiotherapist or exercise physiologist can help develop an appropriate program depending on your symptoms and level of activity.
Weight management can also be useful where appropriate, because the hip experiences forces several times body weight during normal walking.
What about medications?
Simple analgesic medications can help manage symptoms.
Anti-inflammatory medications can also be useful for some patients, although they’re not appropriate for everyone and need to be considered in the context of your general health and other medications.
The aim of medication isn’t to cure the arthritis — unfortunately, we currently don’t have a medication that can reliably restore severely damaged articular cartilage.
Instead, medication is used to help control symptoms and allow you to remain active.
What about injections?
Injections can have a role in selected patients.
A corticosteroid injection into the hip can sometimes provide temporary relief from pain and inflammation.
Because the hip joint lies relatively deep within the body, these injections are generally performed using imaging guidance — usually ultrasound or X-ray guidance — to ensure that the injection is placed accurately into the joint.
The effect varies considerably between patients.
For some people it provides useful relief, while for others the improvement may be relatively short-lived.
An injection can also occasionally be useful diagnostically if we’re uncertain whether the pain is actually coming from the hip joint.
When should I consider hip replacement?
Hip replacement becomes an option when arthritis is significantly affecting your quality of life despite appropriate non-operative treatment.
There isn’t a single X-ray finding or pain score that determines when someone should have surgery.
Instead, I look at the overall picture.
Are you struggling to walk the distances you need to?
Have you stopped doing activities that are important to you?
Is the hip interfering with your work?
Are you regularly requiring pain medication?
Is it affecting your sleep?
And, importantly, have reasonable non-operative treatments stopped providing adequate relief?
When those things begin to occur, it may be appropriate to discuss hip replacement.
What happens in a hip replacement?
During a total hip replacement, the damaged ball-and-socket surfaces of the hip are removed and replaced with artificial components.
The damaged femoral head is removed and replaced with a new ball attached to a stem within the femur.
The damaged surface of the socket is also replaced with an acetabular component.
Together, these create a new smooth-bearing surface for the hip.
Modern hip replacement is an extremely successful operation for appropriately selected patients with advanced hip arthritis.
The aim isn’t simply to improve an X-ray.
The aim is to reduce pain, restore movement and allow you to return to the activities that are important to you.
Conclusion
Hip arthritis is very common, but the severity of arthritis and the symptoms it produces vary enormously from person to person.
If you’re experiencing persistent groin pain, increasing stiffness, difficulty putting on shoes and socks, reduced walking distance or pain that’s beginning to interfere with your sleep or everyday activities, it’s worth having the hip properly assessed.
In many cases, treatment doesn’t begin with surgery.
There are a number of ways we can manage symptoms and maintain function.
But when arthritis becomes severe and begins to significantly affect your quality of life, hip replacement can be a very effective treatment.
Ultimately, the right treatment depends not just on your X-ray, but on your symptoms, your activity level and what you want to be able to get back to doing.