How Common Is Hip Dysplasia? Prevalence and Risk Factors

Hip dysplasia affects roughly 1 to 2 percent of newborns worldwide, though the number shifts dramatically depending on how you screen, where you look, and which severity threshold you use. A large systematic review pooling data from dozens of studies estimated the overall infant prevalence at about 1.4 percent, but reported rates in specific populations range from virtually zero to several percent. The condition is not just a pediatric concern: radiographic studies of adults find dysplasia in about 2 to 5 percent of the general population, much of it previously undiagnosed. Understanding the risk factors that drive those numbers, from fetal positioning to swaddling customs, helps explain why the condition clusters so unevenly across populations.

Infant Prevalence by the Numbers

The most comprehensive look at infant prevalence comes from a 2023 meta-analysis that pooled 65 studies and found a combined prevalence of 1.4 percent for developmental dysplasia of the hip (DDH).¹ That figure includes the full spectrum, from mild acetabular shallowness to complete dislocation. When the researchers broke it down by severity, subluxation dropped to about 0.4 percent and true dislocation to about 0.2 percent, meaning the vast majority of cases are mild dysplasia rather than a hip that is out of joint.

Detection rates also depend heavily on the screening method used. A separate meta-analysis found that programs using universal ultrasound screening picked up about 23 cases per 1,000 newborns, while selective ultrasound screening (only scanning babies with risk factors) caught about 4 per 1,000, and clinical examination alone identified roughly 8 per 1,000.² That five-fold difference between universal and selective ultrasound does not mean more babies are actually dysplastic when you scan everyone. It means universal screening catches milder and more transient cases that selective screening misses, many of which resolve on their own.

How Common Is It in Adults

Not every case of hip dysplasia is caught in infancy. A systematic review of adult radiographic studies, covering nearly 11,000 hips, found an overall prevalence of about 2.3 percent in the general adult population.³ Broken down by sex, the rate was roughly 3.8 percent in women and 2.7 percent in men. A Scandinavian study that specifically measured the lateral center-edge angle in over 1,800 adults found a higher figure of 5.2 percent and noted that the condition is “frequently overlooked” in routine care.⁴

The discrepancy between studies mostly comes down to where you draw the measurement cutoff. Some studies define dysplasia as a lateral center-edge angle below 25 degrees, while others use a stricter cutoff of below 20 degrees. That five-degree gap changes the numbers considerably. A study of asymptomatic Asian volunteers using the more generous 20-degree cutoff found a 15 percent prevalence rate, illustrating how definition alone can move the needle.⁵ Meanwhile, a South Asian population study using a 25-degree threshold found only 1.4 percent prevalence.⁶ These are not contradictions; they reflect the fact that hip socket depth exists on a continuum, and the line between “normal” and “dysplastic” is somewhat arbitrary.

The Major Risk Factors

A 2024 meta-analysis of cohort studies identified a clear hierarchy of risk factors for infant DDH.⁷ The factors with the strongest associations were:

• Female sex: Girls are affected roughly four to seven times more often than boys. In one study, females made up 98 percent of infantile DDH cases and 88 percent of those diagnosed in adolescence or adulthood.⁸ The prevailing explanation involves maternal hormones, particularly relaxin and estrogen, which loosen ligaments near the end of pregnancy. Female fetuses may be more susceptible to these hormonal effects, leading to greater joint laxity.
• Breech presentation: Babies positioned bottom-down in the uterus face roughly a four-fold increase in DDH risk. Biomechanical modeling shows that the breech position reduces the forces acting on the developing hip joint, particularly kick force and the mechanical stress that helps mold a deeper socket.⁹
• Family history: Having a first-degree relative with DDH raises the risk by about four times. An Indiana-based study found that about 14 percent of DDH patients had a positive family history.¹⁰
• Firstborn status: First babies carry roughly twice the risk, likely because the uterus is tighter in a first pregnancy, constraining fetal movement.
• Oligohydramnios: Low amniotic fluid restricts the space available for fetal movement and was associated with roughly a four-fold increase in risk.¹¹

Other conditions that physically crowd the fetus, including large birth weight and twin pregnancy, have also been linked to DDH, though with weaker associations. The same meta-analysis found that combined musculoskeletal abnormalities roughly doubled the risk, and even cesarean delivery showed a small but statistically significant association.⁷

Geographic and Ethnic Variation

Perhaps the most striking feature of DDH epidemiology is how wildly the numbers vary by geography and ethnicity. Reported rates range from 0.06 per 1,000 live births in certain African populations to as high as 76 per 1,000 among some Native American groups.¹² That is a thousand-fold difference, which genetics alone cannot explain.

Cultural practices account for a large share of this variation. Populations with traditional swaddling practices that hold the legs in extension tend to have higher DDH rates, while populations that carry infants in a straddle position on the caregiver’s back tend to have much lower rates. The Indiana study found that white and Hispanic children were over-represented among DDH cases compared to their share of births, while Black children were under-represented, though not absent.¹⁰ This pattern holds broadly across the literature, with DDH rates consistently lower in populations of African descent, though the precise reasons remain an open question involving both genetics and infant-carrying traditions.

Swaddling as a Modifiable Risk Factor

Of all the risk factors for DDH, swaddling stands out because it is the most directly preventable. The concern is not swaddling itself but how the legs are positioned. Traditional tight swaddling that binds the legs straight and pressed together prevents the flexed, spread-knee posture that the developing hip joint needs. A review of the evidence concluded that there is “overwhelming” support for a link between restrictive hip positioning and increased DDH rates, and that populations which switched to hip-safe positioning saw their rates drop.¹³

The most direct evidence comes from a randomized trial in Mongolia, where traditional swaddling is common. Infants assigned to the non-swaddling group had abnormal hip findings in 7.5 percent of cases, compared with 40 percent in the swaddling group. The swaddling group developed eight cases of DDH; the non-swaddling group developed zero.¹⁴ The researchers also found a strong correlation between the amount of daily swaddling time and the risk of abnormal findings. Safe swaddling, which keeps the hips free to flex and spread while wrapping the upper body snugly, does not appear to carry the same risk.

Genetics and What Runs in Families

Family clustering of DDH is well documented, but pinpointing specific genes has been slow going. Research confirms that multiple genes are likely involved, but findings have been inconsistent across studies.¹⁵ The most robust genetic finding so far comes from a large genome-wide association study of nearly 10,000 individuals, which identified a gene called GDF5 as a plausible risk factor.¹⁶ GDF5 plays a role in joint and skeletal development, so the connection makes biological sense. But one gene does not come close to explaining the full heritability pattern, and researchers expect that many more genetic variants with small individual effects are involved.

The practical upshot for families is that having a parent or sibling with DDH meaningfully raises a baby’s risk, enough to warrant screening attention, but it does not make the condition inevitable. DDH behaves like most complex conditions: genetics loads the gun, and environmental factors pull the trigger.

Most Mild Cases Resolve on Their Own

One of the most important and least widely understood facts about infant DDH is that the majority of mild cases self-correct without any treatment. A systematic review of natural history studies found a mean spontaneous resolution rate of about 84 percent for mild-to-moderate cases.¹⁷ This is consistent with what clinicians have observed for decades: hips that are mildly unstable or have slightly shallow sockets in the first days of life frequently mature into normal hips within weeks. The American Academy of Pediatrics has noted that the mild instability originally described by Barlow in 250 newborns all resolved spontaneously.¹⁸

This high spontaneous resolution rate creates a real tension in screening programs. Universal ultrasound picks up many hips that would normalize without treatment, potentially leading to unnecessary bracing or follow-up. On the other hand, selective screening misses some genuinely dysplastic hips that will not self-correct. The challenge is distinguishing which infant hips need intervention and which simply need time.

Universal Versus Selective Screening

Countries handle DDH screening very differently. Some, including Austria and Germany, screen every newborn with ultrasound. Others, like the United States and the United Kingdom, use a selective approach: a clinical hip examination for all babies, with ultrasound reserved for those who have risk factors or abnormal exam findings. The debate over which strategy is better has been running for decades and remains unresolved.

Two randomized trials compared the approaches directly. Both found that universal ultrasound screening trended toward fewer late-detected cases, but neither reached statistical significance. In one trial of over 15,000 infants, late detection was 0.13 per 1,000 with universal screening and 0.65 per 1,000 with selective screening. A second trial showed a similar gradient: 0.3 per 1,000 with universal scanning, 0.7 per 1,000 with risk-factor-based scanning, and 1.3 per 1,000 with clinical screening alone.¹⁹ A recent critical review argued that when you account for the long-term costs of missed cases, including complex surgery and early hip replacements, universal screening looks cost-effective.²⁰

The stakes of late detection are real. When DDH is caught early, treatment typically involves a soft harness that holds the hip in a flexed, abducted position for several weeks. A study of Pavlik harness outcomes found that treatment success depended on the severity at diagnosis and the age at which treatment started.²¹ Late-presenting cases, diagnosed after walking age, tend to require open surgery, bone-cutting procedures, and longer recovery. A Malaysian cost analysis found that 86 percent of the total hospital spending on DDH went to treating late-presenting cases, largely because of the surgical complexity involved.²²

When Dysplasia Leads to Osteoarthritis

Untreated or residual dysplasia in adults is one of the recognized pathways to early hip osteoarthritis. The shallow socket means the cartilage bears weight over a smaller contact area, accelerating wear. In a study tracking adults with symptomatic hip dysplasia who did not undergo corrective surgery, about 20 percent developed osteoarthritis, and 11 percent eventually needed a total hip replacement. The average time from initial pain to osteoarthritis was just over 11 years.²³

Not every dysplastic hip deteriorates, though. A review of studies on adult-diagnosed dysplasia found that joint subluxation, incongruity, a history of hip pain, and any early radiographic signs of arthritis at the time of diagnosis were the strongest predictors of future degeneration.²⁴ A mildly shallow socket in someone with no symptoms and no arthritic changes may never cause trouble. This is part of why the adult prevalence figures are so tricky to interpret: a radiographic finding of dysplasia is not the same as a clinical problem.

Associated Conditions to Watch For

DDH does not always arrive alone. It clusters with certain other musculoskeletal conditions, and recognizing that overlap matters for screening. One study found that about 8 percent of children with DDH also had congenital muscular torticollis (a tightness in the neck that tilts the head to one side), and that 12.5 percent of children with torticollis had DDH.²⁵ Other conditions that show up at higher-than-expected rates alongside DDH include plagiocephaly (a flat spot on the skull), metatarsus adductus (an inward curve of the foot), clubfoot, and early-onset scoliosis.²⁶ The common thread seems to be intrauterine crowding: the same constrained fetal environment that predisposes to a shallow hip socket can also shape the skull, spine, and feet.

For pediatricians and parents, the practical takeaway is straightforward: if a baby is diagnosed with one of these conditions, the hips deserve a careful look, and vice versa.

Borderline Dysplasia and Active Adults

Between clearly normal and clearly dysplastic hips sits a borderline zone that is getting more clinical attention, particularly in athletes and active young adults. Borderline dysplasia is typically defined as a lateral center-edge angle between 18 and 25 degrees: shallow enough to affect joint mechanics but not shallow enough to clearly warrant corrective bone surgery.²⁷

This gray area matters because borderline dysplasia can coexist with femoroacetabular impingement, a condition where extra bone on the hip socket’s rim or the femoral head causes pinching during movement. Treating the impingement arthroscopically without recognizing the underlying shallowness can sometimes make things worse by removing bone from an already-deficient socket. A study of professional and Olympic athletes with borderline dysplasia who underwent hip arthroscopy for impingement found that 79 percent returned to sport after a first surgery, but that rate dropped to 25 percent for revision procedures.²⁸ The steep drop-off underscores that getting the diagnosis right the first time matters, and that borderline dysplasia is not something to brush aside as a normal variant without monitoring it.

Why Dogs Keep Coming Up in the Research

If you have ever heard of hip dysplasia in the context of pets, particularly large-breed dogs, there is good reason for the crossover. Dogs are naturally prone to the condition, and canine hip dysplasia shares enough features with the human version that researchers use it as an animal model for studying the disease. The progression from a loose, shallow hip socket in youth to osteoarthritis in adulthood tracks similarly across species, and surgical approaches overlap as well.²⁹ This parallel means that veterinary advances in hip dysplasia screening and treatment occasionally feed back into human orthopedics, and vice versa. It also means that the basic mechanics of the condition, a socket that does not fully cover the ball of the femur, are not a quirk of human anatomy but a vulnerability shared across species that bear weight on their hind limbs.