Do bones form where they shouldn't? Let's talk about this Heterotopic Ossification!

Can you imagine bones growing inside your muscles and soft tissues around your joints instead of where they should be? Sounds a bit strange, doesn't it? But it's actually possible. This is what we call heterotopic ossification in medicine. Simply put, it's the abnormal formation of new bone outside the skeleton. The bones that form in this way can grow up to three times faster than normal bones. This can cause stiffness and pain in your joints.

This condition doesn't affect everyone the same. It depends on where the extra bone grows and how much of it grows. It's most often seen in the hip area. But it can also affect places like the knees, shoulders, and elbows. Okay, let's learn more about this now.

There are two main types of this.

Heterotopic Ossification can be divided into two main types: those caused by genetic causes and those caused by non-genetic causes.

• Genetic type: This is very rare . Some genetic conditions can cause extra bones to form in the body.
• Non-genetic type: This can happen to anyone. It is most common after a traumatic injury or hip replacement surgery. This condition usually occurs between 3 and 12 weeks after the injury or surgery. However, sometimes these abnormal bones can develop within a few days or even months.

Why is this happening? What are the reasons?

As we discussed earlier, the main cause of this is total hip replacement surgery. Between 28% and 61% of people who have this surgery develop some degree of this extra bone formation. Most often, it forms around the metal hardware used during the surgery.

Apart from this, there are several other causes that affect the condition of Heterotopic Ossification that are not genetic.

Who is most at risk of developing this?

The genetic type has been reported in less than 5,000 cases worldwide. It is very rare.

However, the non-genetic type can occur in anyone, especially if you have been in a serious accident or have undergone surgery.

What are the symptoms of this?

The symptoms of this vary from person to person. It depends on the location and amount of extra bone formation. Common symptoms seen in the early stages include:

• Pain or tenderness in the affected area.
• The area is swollen .
• Some people may develop a fever , especially at night, which may be higher than during the day.

When the condition is a little more severe, you may be able to feel this new bone formation under the skin as a lump . If you press on it, it will feel hard and hard, and you won't be able to move it easily. This bone formation is usually rough and sharp, so it may be painful to touch. If this bone formation is near a joint, it will gradually become difficult to bend or straighten that joint, and it will start to hurt.

If it is caused by genetic diseases...

If you have this condition due to a genetic condition like FOP or POH, your symptoms may be a little different. In FOP, you may see abnormal shapes in your hands, feet, and back. If this bone growth continues, it can affect your ability to walk and even breathe. Your doctor will be very concerned about these severe symptoms.

In POH, the bones first form in the subcutaneous fat layer between the skin and muscles. Over time, these can spread deeper into the soft tissues and connective tissue.

How does a doctor find this?

The early symptoms of this condition, such as fever, swelling, and joint pain, can sometimes be mistaken for other medical conditions.

Therefore, your doctor may order various tests to rule out other medical conditions and to see if these extra bone fragments are present.

• Blood tests
• Various imaging tests :
• Ultrasound scan
• X-ray
• MRI scan
• CT scan
• PET scan

If you have this condition after an accident or hip replacement surgery, your doctor will likely classify the growth of these bone fragments into stages 1 to 4. The most commonly used classification for this is the Brooker classification . It simply goes like this:

• Grade 1: This is the earliest stage. Small bone spurs begin to form in the tissues around the hip.
• Grade 2: The bone fragments have spread to other parts of the pelvis and femur. There is a gap of at least 1 centimeter between the bone fragments.
• Grade 3: The bone fragments have become larger, and the distance between them is less than 1 centimeter.
• Grade 4: This is the final stage. The bones fuse together, and the joint becomes immobile.

How is it treated?

Once your doctor has diagnosed the condition, there are several treatment options. The treatment you receive will depend on how far the disease has spread and how severe your symptoms are.

• Medication: Your doctor may prescribe painkillers to control pain and medications such as corticosteroids to prevent or control new bone formation.
• Physical therapy: Physical therapy is very helpful for many people. The exercises suggested by a physical therapist can help you maintain or improve the range of motion in your joints. It can also help manage pain.
• Surgery: If your condition is severe enough to affect your daily activities, your doctor may recommend surgery to remove the extra bone. However, this is usually a last resort . This surgery is also done after the new bone growth has stopped, that is, after it has matured. If you have surgery before then, it can grow back.
• Radiation therapy: Because these bones can grow back after surgery, doctors sometimes recommend radiation therapy to prevent it.

Can this be prevented from happening?

Since it's hard to pinpoint the exact cause of heterotopic ossification, it's also difficult to prevent it. However, some medications have been found to prevent or slow down the growth of this abnormal bone.

For example, the blood thinner Coumadin (Warfarin) can help with this. This is because vitamin K is essential for bone growth, and Coumadin reduces the body's ability to make vitamin K. Non-steroidal anti-inflammatory drugs (NSAIDS) can also help prevent this condition by blocking the formation of bone cells.