summary Developmental Dysplasia of the Hip is a disorder of abnormal development resulting in dysplasia, subluxation, and possible dislocation of the hip secondary to capsular laxity and mechanical instability. Diagnosis can be confirmed with ultrasonography in the first 4 months and then with radiographs after femoral head ossification occurs (~ 4-6 months). Treatment varies from Pavlik bracing to surgical reduction and osteotomies depending on the age of the patient, underlying etiology, and the severity of dysplasia. Epidemiology Incidence most common orthopaedic disorder in newborns dysplasia is 1:100 dislocation is 1:1000 Demographics more common in females (6:1) more commonly seen in Native Americans and Laplanders due to cultural traditions such as swaddling with hips together in extension rarely seen in African Americans Anatomic location most common in left hip (60%) due to the most common intrauterine position being left occiput anterior (left hip is adducted against the mother's lumbrosacral spine) bilateral in 20% Risk factors firstborn due to unstretched uterus and tight abdominal structures compressing the uterus female due to increased ligamentous laxity that transiently exists as the result of circulating maternal hormones and the estrogens produced by the fetal uterus breech more commonly seen in female children, firstborn children, and pregnancies complicated by oligohydramnios higher risk of DDH with frank/single breech position compared to footling breech position family history oligohydramnios macrosomia limited hip abduction talipes swaddling Etiology DDH encompasses a spectrum of disease that includes dysplasia shallow or underdeveloped acetabulum subluxation displacement of the joint with some contact remaining between the articular surfaces dislocation complete displacement of the joint with no contact between the original articular surfaces teratologic hip dislocated in utero and irreducible on neonatal exam presents with a pseudoacetabulum associated with neuromuscular conditions and genetic disorders commonly seen with arthrogryposis, myelomeningocele, Larsen's syndrome, Ehlers-Danlos late (adolescent) dysplasia mechanically stable and reduced but dysplastic Pathophysiology etiology initial instability thought to be caused by maternal and fetal laxity, genetic laxity, and intrauterine and postnatal malpositioning pathoanatomy initial instability leads to dysplasia login to view 2 more bullets dysplasia leads to subluxation and gradual dislocation login to view 1 more bullet chronic dislocation leads to login to view 11 more bullets Associated conditions associated with "packaging" deformities which include congenital muscular torticollis (20%) metatarsus adductus (10%) congenital knee dislocation conditions characterized by increased amounts of type III collagen Classification Can be classified as a spectrum of disease involvement (phases) subluxable Barlow-suggestive dislocatable Barlow-positive dislocated Ortolani-positive early when reducible; Ortolani-negative late when irreducible Presentation Physical exam (< 3 months) mainstay of physical diagnosis is palpable hip subluxation/dislocation on exam Barlow login to view 2 more bullets Ortolani login to view 2 more bullets Galeazzi (Allis) login to view 2 more bullets hip clicks are nonspecific findings Barlow and Ortolani are rarely positive after 3 months of age because of soft-tissue contractures that form around the hip Physical exam (> 3 months to 1 year) limitations in hip abduction most sensitive test once contractures have begun to occur occurs as laxity resolves and stiffness begins to occur decreased symmetrically in bilateral dislocations leg length discrepancy predominates Klisic test used to detect bilateral dislocations line from the long finger placed over the greater trochanter and the index finger over the ASIS should point to the umbilicus if the hip is dislocated, the line will point halfway between the umbilicus and pubis Physical exam (> 1 year - walking child) pelvic obliquity lumbar lordosis in response to hip contractures resulting from bilateral dislocations in a child of walking age Trendelenburg gait results from abductor insufficiency toe-walking attempt to compensate for the relative shortening of the affected side Imaging Radiograph indications becomes primary imaging modality at 4-6 mo after the femoral head begins to ossify positive physical exam leg length discrepancy recommended views AP of pelvis measurements hip dislocation login to view 12 more bullets hip dysplasia login to view 7 more bullets Ultrasound indications primary imaging modality from birth to 4 months login to view 1 more bullet positive physical exam risk factors (family history or breech presentation) login to view 1 more bullet monitoring of reduction during Pavlik harness treatment most studies show it is not cost effective for routine screening findings evaluates for acetabular dysplasia and/or the presence of a hip dislocation allows view of bony acetabular anatomy, femoral head, labrum, ligamentum teres, hip capsule normal ultrasound in patients with soft-tissue clicks will have normal acetabular development measurements alpha angle login to view 2 more bullets beta angle login to view 2 more bullets femoral head is normally bisected by a line drawn down from the ilium staging Graf classification Graf Classification Class Alpha angle Beta angle Description Treatment I > 60° < 55° Normal None II 43-60° 55-77° Delayed ossification Variable III < 43° > 77° Subluxated Pavlik harness IV Unmeasurable Unmeasurable Dislocated Pavlik harness/closed vs. open reduction Arthrogram indications used to confirm reduction after closed reduction under anesthesia help identify possible blocks to reduction inverted labrum login to view 2 more bullets inverted limbus login to view 2 more bullets transverse acetabular ligament login to view 2 more bullets hip capsule is constricted by iliopsoas tendon causing hourglass deformity of the capsule pulvinar login to view 2 more bullets ligamentum teres login to view 2 more bullets CT historically the study of choice to evaluate reduction of the hip after closed reduction and spica casting MRI increasingly used to evaluate reduction of hip after closed reduction and spica casting in order to minimize radiation compared to CT Screening All infants require screening physical exam successful screening requires repetitive screening until walking age ultrasound ultrasound screening of all infants occurs in many countries; however, it has not been proven to be cost-effective USA recommendation is to perform ultrasound at 4-6 weeks in patients with login to view 2 more bullets AAP recommends an US study at 6 weeks in patients who are considered high risk (family history or breech presentation) despite normal exam also utilized to follow Pavlik treatment or for equivocal exams Treatment in Children Non-operative abduction splinting/bracing (Pavlik harness) indications login to view 1 more bullet contraindicated in teratologic hip dislocations and patients with spina bifida or spasticity login to view 1 more bullet closed reduction and spica casting indications login to view 2 more bullets Operative open reduction and spica casting indications login to view 2 more bullets open reduction and femoral osteotomy indications login to view 4 more bullets open reduction and pelvic osteotomy indications login to view 4 more bullets Techniques Abduction splinting/bracing (Pavlik harness) goals treatment is based on an early concentric reduction in order to prevent future degeneration of the hip risk, complexity, and complications are increased with delays in diagnosis technique positioning login to view 2 more bullets confirm position with ultrasound or radiograph and monitor every 4-6 weeks worn for 23 hours/day for at least 6 weeks or until hip is stable wean out of harness over 6-8 weeks after hip has stabilized until normal anatomy develops discontinue if hip is not reduced by 3-4 weeks to prevent Pavlik disease complications specific to this treatment AVN login to view 4 more bullets transient femoral nerve palsy login to view 1 more bullet Pavlik disease login to view 2 more bullets outcomes overall success rate of 90% login to view 1 more bullet abandon Pavlik harness treatment if not successful after 3-4 weeks If Pavlik harness fails, consider converting to semi-rigid abduction brace with weekly ultrasounds for an addition 3-4 weeks before considering further intervention Closed reduction and spica casting anesthesia performed under general anesthesia login to view 1 more bullet technique closed reduction login to view 1 more bullet arthrogram login to view 4 more bullets adductor tenotomy login to view 1 more bullet spica casting login to view 5 more bullets complications specific to this treatment AVN login to view 7 more bullets Open reduction approach anterior approach (Smith-Peterson) login to view 3 more bullets medial approach login to view 18 more bullets soft tissue remove possible anatomic blocks to reduction login to view 1 more bullet perform adductor tenotomy if the patient has an unstable safe zone (i.e. if excessive abduction is required to maintain the reduction) post-op immobilize in functional position of 30° of flexion, 30° of abduction and 30° of internal rotation Femoral Varus DeRotational Osteotomy (VDRO) indications femoral shortening login to view 2 more bullets correct excessive femoral anteversion and/or valgus used after femoral head is congruently reduced with satisfactory ROM and reasonable femoral sphericity Pelvic Osteotomies indications increase anterior or anterolateral coverage increased acetabular index consistent with acetabular dysplasia used after reduction is confirmed on abduction-internal rotation views and satisfactory ROM has been obtained Reconstructive Pelvic Osteotomies Type Indication Technique Salter Younger patients typically with open triradiate cartilage Single transverse cut above the acetabulum through the ilium to sciatic notch Acetabulum hinges through the pubic symphysis Improves anterolateral coverage (can provide 20-25° lateral and 10-15° anterior coverage) May lengthen leg up to 1cm Triple (Steele) Favored in older children because their symphysis pubis does not rotate well Performed when open triradiate cartilages are present Salter osteotomy plusadditional cutsthrough superior and inferior pubic rami Acetabular reorientation procedure Improves anterolateral coverage PAO (Ganz) Triradiate cartilage must be closed in order to perform Involves multiple osteotomies in the pubis, ilium, and ischium near the acetabulum Allows for improved 3D correction of the acetabulum configuration Technically the most challenging Posterior column and pelvic ring remain intact Patients are allowed to weight bear early Pemberton For moderate to severe DDH Most versatile Triradiate cartilage must be open Osteotomy starts approximately 10-15mm above the AIIS and proceeds posteriorly to end at the level of the ilioischial limb of the triradiate cartilage (halfway between the sciatic notch and the posterior acetabular rim) Acetabulum hinges at the triradiate cartilage posteriorly and the symphysis pubis anteriorly Does not enter the sciatic notch and is therefore stable and does not need internal fixation Improves anterolateral coverage Reduces acetabular volume Dega Favored in neuromuscular dislocations (CP) and patients with posterior acetabular deficiency For severe cases Osteotomy from acetabular roof to triradiate cartilage (incomplete cuts through pericapsular portion of the innominate bone) Acetabulum hinges through the triradiate cartilage Does not enter the sciatic notch and is therefore stable and does not need internal fixation Improves anterior, central, or posterior coverage Reduces the acetabular volume Dial Technically difficult Rarely used Leaves the medial wall or teardrop in its original position and is therefore intra-articular Spherical osteotomy Salvage pelvic osteotomies Type Indications Technique Shelf Salvage procedure performed in patients > 8 years old Add bone to the lateral weight-bearing aspect of the acetabulum by placing an extra-articular buttress of bone over the subluxed femoral head Depends on fibrocartilage metaplasia for successful results Chiari Salvage procedure for patients with inadequate femoral head coverage and when a concentric reduction can not be obtained Osteotomy starts above the acetabulum to the sciatic notch and ileum is shifted lateral beyond the edge of the acetabulum Depends on fibrocartilage metaplasia for successful results Medializes the acetabulum via iliac osteotomy Complications AVN seen with all forms of treatment increased rates associated with excessive or forceful abduction previous failed closed treatment repeat surgery diagnosis based on radiographic findings that include failure of appearance or growth of the ossific nucleus 1 year after the reduction broadening of the femoral neck increased density and fragmentation of ossified femoral head residual deformity of proximal femur after ossification Delayed diagnosis bilateral dislocations patients typically function better if hips are not reduced if 6 years of age or older unilateral dislocation better outcomes without surgical treatment if the patient is > 8 years old epiphysiodesis can be performed for treatment of limb length discrepancy Recurrence approximately 10% with appropriate treatment requires radiographic follow-up until skeletal maturity Transient femoral nerve palsy seen with excessive flexion during Pavlik bracing