Sacral insufficiency fracture

Sacral fracture occurring under ordinary loads when bone strength is reduced.

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Understanding the mechanism

A sacral insufficiency fracture occurs when ordinary loads exceed the strength of weakened sacral bone. It often affects the sacral wings and can occur on both sides. Osteoporosis is a common cause; pelvic irradiation, corticosteroids and some bone disorders can also contribute. This differs from a fatigue fracture in normal bone exposed to unusually high repetitive loading.

Symptoms and warning signs

Lower-back, buttock or groin pain commonly increases with weight-bearing and may substantially limit walking. A clear traumatic event is not required. The presentation can resemble mechanical back pain, sciatica or hip disease. New severe pain, inability to walk or neurological symptoms needs medical assessment rather than continuing empirical mechanical treatment under an assumed muscular diagnosis.

Diagnosis and investigations

Plain radiographs can miss the fracture. MRI of the pelvis or sacrum is useful for detecting bone-marrow oedema, while CT defines fracture lines and anatomy. The choice depends on the clinical question and previous investigations. A lumbar MRI that does not adequately cover the sacrum cannot always exclude this diagnosis, even if no obvious lumbar cause is found.

Treatment and outlook

Management includes pain control, appropriate weight-bearing modification, safe mobilization and treatment of bone fragility. Prolonged bed rest carries risks of its own, so progression should be supervised. Sacroplasty or fixation may be considered in selected painful or unstable presentations. Recovery is monitored through walking ability, independence and healing rather than symptoms at rest alone.

The role of TAGMED care

At TAGMED, unusual buttock pain in an at-risk person should raise this possibility before manipulation, percussion or spinal decompression. These procedures do not repair a sacral fracture and can apply unsuitable loads. After medical clarification, support should be limited to permitted activity, fall prevention and musculoskeletal needs compatible with the recovery phase and the treating team's guidance.

Practical follow-up

A brief record of walking distance and assistance needed can guide progression after medical clearance. Pain at rest alone says little about weight-bearing capacity. The team should know what happens during transfers and walking when deciding how to advance activity.

Frequently asked questions

Does a fall have to occur?

No. Insufficiency fractures can develop under ordinary everyday loading.

Does a normal X-ray rule it out?

No. More sensitive imaging may be needed when clinical suspicion remains.

Is this the same as sacroiliitis?

No. One is a bone fracture, the other a joint problem, although their pain can overlap.

Why investigate osteoporosis?

The fracture may reveal a fragility problem that increases the risk of other fractures.

When can walking resume?

According to stability and symptoms, with progression and aids advised by the treating team.

Educational information from The Spine Page. This entry does not replace an individual assessment. Documentary version: October 12, 2026. Sylvain Desforges, B.Sc., D.O., N.D., osteopath and naturopath.