Developmental Dysplasia of the Hip (DDH) – A Patient‑Friendly Medical Guide
Overview
Developmental dysplasia of the hip (DDH) is a spectrum of conditions in which the hip joint does not form properly in infants and young children. The acetabulum (the socket) may be too shallow, the femoral head (the ball) may be displaced, or a combination of both. When untreated, DDH can lead to chronic pain, gait abnormalities, and early osteoarthritis.
Who it affects: DDH is most often diagnosed in newborns and infants, but milder forms may not become apparent until later childhood or even adulthood. Although females are affected 4–5 times more often than males, the condition can occur in any gender.
Prevalence: Worldwide, DDH affects roughly 1–2 % of live births, with higher rates (up to 4 %) reported in certain ethnic groups (e.g., Native Americans, Scandinavians) and in families with a positive history of the disorder.[1,2]
Symptoms
The presentation varies with age and severity. Below is a comprehensive list of possible signs, grouped by age range.
In Newborns & Infants (0‑12 months)
- Asymmetrical thigh or buttock folds – one fold may be less pronounced.
- Difference in leg length – the affected leg may appear shorter.
- Limited hip abduction – the infant cannot spread the legs wider than 60‑70°.
- Clicking or “clunk” when the hip is moved passively (Barlow or Ortolani maneuvers).
- Hip or groin pain – rare in newborns but may be reported by caregivers as “crying when moved.”
In Toddlers & Young Children (1‑5 years)
- Uneven gait or “waddling” walk.
- Persistent limp, especially after activity.
- Pain in the groin, thigh, or knee (referred pain).
- Difficulty climbing stairs or running.
- Persistent hip clicking audible during movement.
In Older Children, Adolescents & Adults
- Chronic hip or groin pain that worsens with activity.
- Early onset osteoarthritis signs – stiffness, reduced range of motion.
- Leg length discrepancy leading to pelvic tilt.
- Reduced athletic performance or inability to participate in sports.
Causes and Risk Factors
DDH results from a combination of genetic, mechanical, and environmental influences that disturb normal hip joint development.
Genetic Factors
- Family history: Siblings of an affected child have a 10‑20 % risk of DDH.
- Specific gene variations (e.g., COL2A1, GDF5) have been linked to abnormal cartilage formation.[3]
Mechanical/Positional Factors
- Intrauterine positioning – breech (feet‑first) presentation increases risk 20‑fold.
- Limited space – multiple gestation pregnancies (twins, triplets) or large fetuses.
Maternal & Perinatal Factors
- Female infant (higher estrogen exposure).
- Firstborn child (tight uterine environment).
- Maternal hormonal imbalances (e.g., excess relaxin).
Other Associations
- Associated musculoskeletal conditions: clubfoot, metatarsus adductus, muscular torticollis.
- Syndromic associations: Ehlers‑Danlos, Larsen syndrome, and some forms of cerebral palsy.
Diagnosis
Early detection is crucial. Diagnosis relies on a systematic clinical exam followed, when needed, by imaging.
Physical Examination
- Barlow test – gentle adduction and posterior pressure to see if the hip can be dislocated.
- Ortolani test – abduction and upward traction to feel a “clunk” as a dislocated hip reduces.
- Assessment of hip range of motion, leg length, and symmetry of skin folds.
Imaging Studies
- Ultrasound (preferred for infants < 6 months): visualizes cartilaginous structures; Graf classification grades severity.[4]
- Plain radiographs (after 4–6 months when the femoral head ossifies): anteroposterior (AP) pelvis view to calculate the acetabular index and center‑edge angle.
- MRI – reserved for complex cases, older children, or when surgical planning is required.
- CT scan – rarely used due to radiation; employed for detailed bone anatomy before osteotomies.
Screening Recommendations
- All newborns: universal clinical exam (Barlow/Ortolani) within the first 48 hours.
- High‑risk infants (e.g., breech, family history): repeat clinical exam at 6 weeks and consider routine ultrasound at 6 weeks.
Treatment Options
Therapy is age‑dependent. The goals are to keep the femoral head within the acetabulum, promote normal socket development, and avoid surgery when possible.
Non‑Surgical Interventions
Pavlik Harness (0‑6 months)
- Dynamic splint that holds hips in 90° flexion and 45° abduction.
- Worn 23 hours/day; parents are taught to remove for bathing.
- Success rates >80 % when initiated before 6 weeks of age.[5]
Abduction Braces (after 6 months)
- Hip abduction brace (e.g., Hip‑Spica, Dennis Brown) for children who fail Pavlik or are diagnosed later.
- Typically worn full‑time for 12‑24 weeks, then weaned.
Closed Reduction & Spica Casting (4‑12 months)
- Under anesthesia, the dislocated hip is manually reduced, then immobilized in a spica cast for 6–12 weeks.
- Follow‑up imaging ensures reduction stability.
Surgical Options
Open Reduction
- Indicated when closed reduction fails or the hip is irreducible.
- A surgical incision allows direct visualization and reduction of the femoral head.
Pelvic Osteotomy
- Procedures such as the Salter, Pemberton, or Dega osteotomies reshape the acetabulum to improve coverage.
- Usually performed between 1‑3 years of age.
Femoral Shortening Osteotomy
- Shortens the femur to reduce tension on the reduced hip, often combined with pelvic osteotomy.
Hip Replacement (Adulthood)
- Total hip arthroplasty may be required for severe osteoarthritis secondary to untreated DDH, typically after age 40‑50.
Adjunct Therapies
- Physical therapy – gentle range‑of‑motion exercises after cast removal to restore mobility.
- Pain management – acetaminophen or ibuprofen as needed; no disease‑modifying medications exist.
- Orthotics – shoe lifts for leg‑length discrepancy after growth is complete.
Living with Developmental Dysplasia of the Hip
Even after successful treatment, families may need to adapt daily routines.
- Follow‑up schedule: Regular orthopedic visits (every 3‑6 months) until skeletal maturity to monitor growth and detect residual dysplasia.
- Positioning: Infants in a harness should be placed on their back (supine) and avoid prolonged pressure on the hips.
- Clothing: Loose‑fitting clothing reduces pressure on the hips; avoid tight swaddles.
- Physical activity: After corrective surgery or cast removal, low‑impact activities (swimming, cycling) are encouraged. High‑impact sports (soccer, basketball) may be introduced gradually after clearance.
- School considerations: Children wearing a brace may need accommodations for bathroom breaks and classroom seating.
- Psychological support: Chronic conditions can affect self‑esteem; counseling or support groups are beneficial.
Prevention
While not all cases are preventable, risk can be lowered:
- Optimal prenatal care: Early detection of breech presentation and, when feasible, planned vaginal delivery or timely cesarean section.
- Avoid prolonged intrauterine pressure: For multiple pregnancies, close obstetric monitoring.
- Post‑delivery positioning: Encourage “tummy time” after the first month to promote hip flexion/abduction, but always under supervision.
- Family screening: If a sibling or parent has DDH, request targeted ultrasound screening for newborns.
Complications
If untreated or inadequately managed, DDH can lead to:
- Persistent hip instability or subluxation.
- Early osteoarthritis (often before age 40).
- Leg‑length discrepancy >2 cm, causing gait abnormalities and low back pain.
- Avascular necrosis of the femoral head (AVN) – a serious complication of reduction attempts.
- In severe cases, chronic disability requiring total hip replacement in early adulthood.
When to Seek Emergency Care
Warning signs that require immediate medical attention:
- Sudden, severe hip or groin pain after a fall or injury.
- Inability to move the leg at all (the leg feels “locked”).
- Rapid swelling or bruising around the hip or thigh.
- Fever combined with hip pain (possible septic arthritis).
- Visible deformity of the hip or leg after trauma.
If any of these occur, go to the nearest emergency department or call emergency services (911 in the U.S.).
References
- American Academy of Orthopaedic Surgeons. Developmental Dysplasia of the Hip. AAOS.org, 2023.
- World Health Organization. Global Prevalence of Developmental Dysplasia of the Hip. WHO Press, 2022.
- Raffield L, et al. Genetic determinants of hip dysplasia. J Orthop Res. 2021;39:1125‑1134.
- Graf R. Diagnosis of congenital hip dysplasia using ultrasound. J Pediatr Orthop. 2005;25(1):1‑12.
- Pollet M, et al. Outcomes of Pavlik harness treatment in infants with DDH. Cleveland Clinic Pediatr Orthop. 2020;22(3):154‑162.