Transient osteoporosis of the hip, or bone marrow edema syndrome of the hip, is a rare form of osteoporosis. It involves a temporary loss of bone density from the head of your femur (the ball portion of the ball-and-socket joint).

Osteoporosis is a common condition in which your bone density is lower than usual. It’s estimated to affect about 10 million people over age 50 in the United States.

Transient osteoporosis of the hip (TOH) is most common in middle-aged men, as well as in women who are in the third trimester of pregnancy or the postpartum period. It’s estimated to occur in 1 in 250,000 pregnancies.

Researchers still aren’t sure what causes TOH, but they believe that factors such as blockages in the small blood vessels around the hip and abnormal stress on the hip joint may play a role.

Let’s examine what’s known about TOH, including symptoms, potential causes, and treatment options.

TOH usually starts as a dull pain in your groin or buttocks that radiates into your thigh and leg. It tends to get progressively worse over weeks to months and can become severe. Other possible symptoms include:

  • pain that worsens with walking, weight bearing, or strenuous activity
  • slightly limited range of motion
  • limping

TOH usually affects one hip but may affect both hips in up to 30% of cases. Symptoms tend to go away within 6 to 12 months.

Researchers are still trying to figure out why some people develop TOH. They haven’t yet identified a definitive cause but believe that the following factors may play a role in its development:

  • blockages of small blood vessels around the hip
  • abnormal stress on the hip bone
  • hormone changes, such as severe hypothyroidism

Compression of a person’s obturator nerve by a baby’s head during pregnancy has also been suggested as a contributing factor.

TOH most often occurs in men ages 30 to 60 and women who are in the last 3 months of pregnancy or have recently given birth.

Men develop TOH about three times more often than women.

Risk factors not proven but hypothesized to be linked to TOH include:

TOH increases your risk of developing a hip fracture. Symptoms of TOH tend to subside after 6 to 12 months, and most people regain full bone strength.

In a small 2017 study, researchers found that, out of 33 women with pregnancy-associated TOH, 12.1% developed hip fractures.

Treatment for TOH focuses on reducing your symptoms and speeding up your recovery.

Home treatment

Home treatment of TOH might include:

Medical treatment

In a small 2019 study that included data from 19 people, researchers found evidence that the bisphosphonate zoledronic acid may help speed up the reversibility of TOH.

Some evidence suggests that hip drilling may speed up TOH recovery. This procedure involves drilling holes in the head of your femur to create channels for new blood vessels.

Surgical repair or hip replacement may be necessary to treat hip fractures.

Transient osteoporosis of the hip exercises

Hip-strengthening and range-of-motion exercises may help protect your hip from fracture. A physical therapist or another qualified professional can best advise you on which exercises to perform. Examples of exercises they may recommend include:

Learn more about exercises to increase hip strength and mobility.

The National Health Service recommends seeing a doctor if your hip pain:

  • affects your daily activities or sleep
  • gets worse or returns
  • hasn’t improved after 2 weeks of home treatment
  • is accompanied by hip stiffness more than 30 minutes after waking up

TOH is primarily diagnosed through imaging. Magnetic resonance imaging (MRI) is the imaging technique of choice. It can show swelling within 48 hours, while X-rays may not show evidence of TOH for 21 to 42 days.

Blood tests or urine tests may help identify other conditions that could be causing your symptoms.

Here are some frequently asked questions people have about TOH.

What is transient osteoporosis of the hip?

TOH is a temporary decrease in the bone density of your hip. Researchers are not entirely sure what causes it.

How serious is transient osteoporosis of the hip?

TOH can cause severe disability, but the symptoms tend to go away within 1 year. Decreased bone density can increase your risk of a hip fracture.

What can be done for transient osteoporosis of the hip?

Treatment for TOH may include home remedies such as rest and NSAIDs to reduce your symptoms. A type of surgery called hip drilling or medications called bisphosphonates may help speed up recovery.

Can you prevent transient osteoporosis of the hip?

Researchers aren’t entirely sure what causes TOH or how to prevent it. Eating a balanced diet, addressing any hormonal imbalances, and avoiding smoking may theoretically reduce your risk.

TOH is a rare condition characterized by a temporary decrease in the bone density of the head of your femur. Researchers are not entirely sure what causes it.

TOH usually resolves after 6 to 12 months. Your doctor may recommend treatments such as physical therapy, NSAIDs, or bisphosphonates to speed up your recovery and reduce your symptoms.