What a joint is, and what wears out, what “bone on bone” means
The hip is a ball-and-socket joint: the ball at the top of your thigh bone sits in a socket in the pelvis. The knee is a hinge between the thigh bone and the shin bone, with the kneecap gliding in front. In a healthy joint, the ends of the bones are covered by cartilage, a smooth, slightly springy layer that lets the surfaces glide over each other almost without friction.
Osteoarthritis is the gradual loss of that cartilage layer. As it thins, the joint becomes stiffer and less forgiving. In advanced arthritis the cartilage can wear away completely, so that bone rubs on bone. The body reacts by forming extra bone at the edges of the joint (bone spurs), and the joint can slowly change shape.
Osteoarthritis is not simply “wear and tear” from using the joint too much, and it is not your fault. It is a disease of the whole joint, and several things make it more likely:
- Age; it becomes more common from mid-life onwards
- Family history
- Previous injury to the joint, such as a fracture or a torn ligament or meniscus
- Body weight, extra load accelerates wear, particularly in the knee
- The shape of the joint you were born with, such as hip dysplasia
What it feels like
Arthritis usually announces itself gradually. Common symptoms are:
- Pain in or around the joint, hip arthritis is often felt in the groin or thigh, and sometimes in the knee
- Stiffness, especially first thing in the morning or after sitting
- A grinding, clicking or catching feeling
- Reduced movement, difficulty with socks and shoes, stairs, or getting out of a low chair
- A limp, or a change in the way you walk
Symptoms often come and go. Many people have months that are manageable and flare-ups that are not. A bad fortnight does not necessarily mean the joint is deteriorating quickly.
How advanced is it? What the X-ray does and does not tell you
At the consultation, Dr Broadhead will ask about your pain, what it stops you doing, and what you have already tried, and will examine the joint, how it moves, where it is tender, and how you walk.
A plain X-ray, taken standing, is usually the only test needed. It shows how much cartilage space remains and whether the joint has changed shape. The X-ray matters less than you might expect, though: it is the person that is treated, not the picture. Some joints look poor on X-ray and cause little trouble; others look moderate and cause a great deal. The decision about treatment is based on how the joint affects your life, not on the image alone.
MRI scans are rarely needed to diagnose arthritis. They are useful for other problems, soft tissue injuries, or when something on the X-ray needs a closer look, and it will be explained if one is worthwhile in your case.
What happens next
Arthritis is not a one-way street to surgery. The next chapter goes through every option short of an operation, what genuinely helps, what the evidence says, and how to tell when those options have been given a fair go.