What is the Hip Joint?
Many patients think that their hip joint is on their outside, but this is not actually true. What you can feel on the outside of your hip is actually called the greater trochanter, which is a part of your femur bone, but not actually part of the joint.
The ball and socket of your hip joint is actually located beneath your groin. If you pushed a pin through the skin of your groin, it would eventually pop into your hip joint. This is why hip pain is commonly felt in the groin or buttocks. Hip pain can also be referred down your thigh, and even into your knee joint.
The hip joint is right at the top of your entire lower limb, so if your hip is not doing its usual job, every joint below that relies upon it has to compensate.
How Does the Hip Joint Work?
Your hip is a simple ball and socket joint. The socket of the joint is called the acetabulum. The top of your thigh bone, or femur, has a ball on top of it that fits perfectly inside the socket.
Both surfaces of the ball and socket are covered in a smooth substance called articular cartilage. My Grandpa, back in the day, would have referred to this as ‘gristle’. You may have seen cartilage or ‘gristle’ stuck to the end of a bone, such as a chicken wing. It’s exactly the same substance that’s in your joints.
This smooth articular cartilage allows your hip to glide around and move without pain. A normal hip joint lets you move your leg in pretty much any direction; forwards, backwards and also from side to side.
These hip movements are essential for everyday activities; doing the shopping, riding a bike, getting into and out of a car, and even putting on shoes and socks all require your hip joint to move freely.
What Causes Hip Arthritis?
The most common form of hip arthritis, and the form spoken about in the article, is osteoarthritis, which means “arthritis of the bone”. It is more common among older people than younger people, and is caused when the smooth articular cartilage of your hip joint wears away as a result of wear and tear on the joint, exposing the bare bone beneath. The hip literally begins to grind, bone on bone, similar to a mortar and pestle that a chef would use to grind up spices.
When looking at an x-ray of a normal hip joint, you can see a clear, dark space between the ball and socket. That dark space is the cartilage inside the joint, which is invisible on an x-ray. However, when looking at an x-ray of an arthritic hip joint, you can see there is no longer any space between the ball and socket. The nice, smooth contour of the joint has also changed. This is because all the cartilage has worn away, and the ball and socket are now grinding together.
What Symptoms of Hip Arthritis Might I Experience?
As arthritis progresses, the hip joint becomes very stiff, and this has a big impact on your function. Remember, you need your hip to move freely to let your lumbar spine and other joints in your lower limb do their jobs properly. That’s why hip arthritis can be so disabling. It’s not just pain; the stiffness of your hip prevents you from doing a large number of activities.
Some of the most common problems patients report include difficulty bending down to pick things off the floor, getting into and out of a chair, and especially getting dressed and pulling on their shoes and socks. Hobbies like playing golf or going for a walk are also challenging.
The more bone and cartilage that grinds away, the more the ball will move deeper into the socket. This makes your entire leg shorter on that side. It’s not uncommon for a patient’s leg to actually be 1-2 centimetres shorter due to their hip arthritis. Because this shortening happens slowly over many years, most patients don’t actually notice it, and they can be surprised when I point this out.
Pain is also a major symptom, and if severe it can make everyday life quite challenging. Loss of sleep and a need to take regular pain medications are common. The hip joint also takes a huge amount of pressure off your lower back, or lumbar spine. So if your hip is stiff and not moving properly, you may experience worsening back pain.
Do I Need Hip Replacement Surgery?
You do not have to get a hip replacement simply because an x-ray or MRI scan shows that you have osteoarthritis. Many patients have arthritis, but their symptoms are mild. You also do not need to be a certain age to have a hip replacement, however, it is worth keeping in mind that hip replacements don’t last as long in younger patients as they do in more elderly patients simply because younger people tend to be more active.
The decision about when is the right time for a hip replacement is a complex and personal one. However, I would strongly encourage you to make a decision based largely on your level of pain and loss of function. Or put simply, how badly is your hip affecting your quality of life?
There is also no rush to have a hip replacement. You have plenty of time to think about your options and try alternative treatments. However, over time, arthritis symptoms do worsen as your joint continues to wear out. We can’t permanently cure arthritis without a joint replacement procedure.
In my experience, most patients have told me that they eventually reached a point where they just knew it was the right time for them to have a hip replacement. Ultimately, this is a personal decision for you to make.