Sacral insufficiency fractures are types of stress fractures that typically occur in older people, especially older people who were assigned female at birth with osteoporosis.

As we age, our bodies and organs change, including our bones. Our bones can get weaker and are more easily broken or fractured, even with normal physical activity.

An insufficiency fracture is a kind of stress fracture that’s caused from normal stress on bone that has lost elastic resistance. A sacral insufficiency fracture is when this kind of fracture occurs to your sacrum, or the bone that’s at the base of the lumbar vertebrae and is part of your pelvis.

The exact prevalence is unknown but is estimated at 1.8%, though this is thought to likely be an underestimate due to underdiagnosis.

This article takes a closer look at sacral insufficiency fractures, their symptoms, causes, and treatment.

Language matters

In this article, we use “female” to refer to someone’s sex as determined by their chromosomes.

Sex is determined by chromosomes, and gender is a social construct that can vary between time periods and cultures. Both of these aspects are acknowledged to exist on a spectrum both historically and by modern scientific consensus.

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The most common symptom of a sacral insufficiency fracture is diffuse low back pain that gets worse with movement and better when resting. Sometimes, this pain can also spread to the buttock, hip, or groin.

There may also be some tenderness to the touch in the lower back area, but not always. In a small percentage of cases (5–6%), there may be sacral radiculopathy, which is when the pain is felt along the sciatic nerve.

Sometimes, the symptoms of a sacral insufficiency fracture often go undiagnosed because they’re mistaken for possible metastatic disease or merely seen as common bodily complaints of aging.

Sacral insufficiency fractures are more likely to occur with age, when our bones are weaker. Normal stress and everyday activities can cause these fractures; there doesn’t need to be a specific physical trauma, such as a fall.

Sacral insufficiency fractures often occur in older people assigned female at birth living with osteoporosis. In fact, osteoporosis is the biggest risk factor for these fractures.

Even if other risk factors are present, nearly everyone with a sacral insufficiency fracture will show severe osteopenia on imaging tests. According to a study from 2010, other risk factors include:

It’s worth remembering that risk factors don’t mean someone with any of these conditions will definitely develop a sacral insufficiency fracture. These factors just increase the risk of one occurring.

Treatment for sacral insufficiency fractures usually involve noninvasive interventions, including:

More invasive interventions include surgical repairs such as percutaneous sacroplasty. Percutaneous sacroplasty is minimally invasive and consists of injecting a kind of bone cement into the affected sacral wing.

Compared with noninvasive treatment, this procedure has been associated with less opioid use for pain, better mobility, and symptom relief.

A 2019 review found sacroplasty to be a safe and effective procedure with low complication rates and consistent pain relief for people with sacral insufficiency fractures.

Recovery and healing times can vary, depending on the severity of the fracture and other factors like:

  • the underlying reason for the fracture
  • the overall health of the individual
  • conditions that may affect healing or bone strength
  • response to treatment

In the past, complete bed rest was recommended for 3–6 months. But this is no longer recommended because of the associated risks of prolonged bed rest.

Symptom relief starts quickly if treated with sacroplasty. A 2019 case study found:

  • a 60% reduction of pain in the first half hour following the procedure
  • a 75% reduction at 4 weeks
  • a 90% reduction at 1 year

Recovery from a sacroplasty can take several months. Talk with a doctor about your specific situation and what recovery might look like, based on the decided treatment approach.

Sacral insufficiency fractures are types of stress fractures that typically occur in older people, especially older people assigned female at birth with osteoporosis. The fractures also occur in those who have had radiation to the pelvis.

Symptoms can be vague and nonspecific, such as lower back pain with or without spreading to the buttock or leg. People often attribute the pain to the aches and stiffness of getting old, which can lead to delays in diagnosis and treatment.

Treatment for sacral insufficiency fractures can be a mix of noninvasive treatment and more invasive surgical procedures like sacroplasty. Recovery time varies, but it’s often several months.