What it is
The pelvis is a ring of bones at the base of the spine: the sacrum and tailbone at the back, and on each side a hip bone made of three parts (the ilium, ischium and pubis), which meet at the hip socket. Because it's a ring, a break in one place often comes with a second break, or torn ligaments, elsewhere in the ring.
Stable breaks (often one break, lined up) include breaks of the wing of the hip bone, partial breaks of the sacrum and breaks of the pubic rami, the thin bars of bone at the front. Unstable breaks (usually two or more, shifted) come from crushing or shearing forces. Pelvic fractures are about 3% of adult fractures.
Source 1
Two very different groupsEmerging evidence
Low-energy (fragility) fractures happen when bones weakened by osteoporosis break in a fall from standing height, or even getting out of the bath or walking downstairs. They're usually stable breaks of one bone, often the pubic rami, but they can be unstable or very painful. In older people, a pubic rami fracture usually follows a fall. In a series of 286 people, pubic rami fractures affected about 7 per 100,000 people a year overall and about 26 per 100,000 over 60; the average age was 75, women were affected 4.2 times as often as men, and a quarter had dementia. NICE (the National Institute for Health and Care Excellence) notes that pelvic fractures are as strongly linked with reduced bone strength as the common fragility fractures of the hip, spine, wrist and shoulder.
High-energy fractures follow car and motorbike crashes, crushes and falls from a height. The pelvis lies close to major blood vessels and organs, so these breaks can bleed heavily and injure the bladder, bowel and nerves, and they often come with head, chest, tummy or leg injuries.
Other pelvic injuries have their own guides: a piece of bone pulled off by a muscle in a young athlete, which rarely makes the pelvis unstable (our hip pointer guide), and stress fractures from repeated load (our stress fracture guide).
Sources 1, 2, 3, 4
How it's recognised, and hidden breaksEmerging evidence
After a low-energy break: pain in the groin, hip or lower back that's worse on moving, tenderness in the groin, mild bruising or swelling, and pain walking; people often keep the hip or knee bent to ease it. It can feel like a broken hip, which has to be ruled out, so the NHS advice after a fall with severe hip pain, or not being able to walk, is 999 or A&E.
X-rays can miss these breaks. Of 63 older people with pubic rami fractures in one hospital's series, 11 were diagnosed only after more scans. In one study of 99 older people whose X-rays showed only the front of the ring broken, a CT (computed tomography) scan found a second break at the back in 6 out of 10. That's a single study, but it explains why a clear X-ray doesn't always end the matter, and why the team may ask for a CT scan, or occasionally an MRI (magnetic resonance imaging) scan. Most low-energy breaks are still treated by walking and pain relief, whatever the scan shows.
Sources 2, 1, 7, 5, 6
How it usually goes after a low-energy breakEmerging evidence
The bone usually heals in 6 to 8 weeks, longer for more severe breaks, with the pain easing gradually. Many people need a hospital stay: in one hospital's series of 63 people who lived at home before, 95% were admitted for pain control and to get walking, for 14 days on average. Of the 38 followed for a year, 92% were living at home, 92% were walking as before, and 84% had little or no groin pain. In a single-centre cohort of 128 people (median age 85), 22.6% moved into a care home after leaving hospital. In 588 people over 65 from 12 hospitals, a third walked less well a year later.
It's a serious injury in later life. In the 588, 91.6% were alive a year later; in the series of 286, 86.7% were alive at a year and 45.6% at 5 years, fewer than other people of the same age, and in that one series from 2001, survival at 5 years was no different from after a broken hip. In 11,624 trauma patients aged 60 and over in Sweden, a pelvic injury independently raised the risk of dying within 30 days and the need for rehabilitation in hospital. Much of this reflects age and other illnesses, and these are observational studies.
Sources 8, 2, 9, 5, 10, 11, 3, 12
How it goes after a high-energy breakEmerging evidence
Stable breaks tend to heal well. After unstable breaks, once bleeding and organ injuries are dealt with, the fracture usually heals well, but a limp can last months and the muscles can take up to a year to recover; pain, reduced mobility, incontinence and sexual problems can follow nerve and organ injury.
In 346 Dutch patients a median of 2.2 years on, full recovery to population levels ranged from 11% to 46% depending on the fracture pattern. In a cohort of 184 people, quality of life improved over 2 years, but almost half still reported pain or discomfort 8 years after the injury, though only about a third answered at 8 years. In 113 people treated with surgery for pelvic or hip socket fractures, 65% of those in work found it hard to go back and 39% never did.
Sources 1, 13, 14, 15
