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78 Cards in this Set
- Front
- Back
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What are the four risk factors for developmental dysplasia of the hip (DDH)?
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Breech
Female Family history First-born |
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What collagen abnormality is associated with DDH?
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Increased type lll collagen
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A similar collagen abnormality is also seen in what condition?
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Dupuytren
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Which hip is most commonly affected?
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Left
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What are two extraarticular obstructions to concentric reduction?
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Tight iliopsoas
Redundant capsule |
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What are four intraarticular obstructions to concentric reduction?
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Inverted labrum (neolimbus)
Ligamentum teres Transverse acetabular ligament Pulvinar (fatty tissue) |
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What is the definition of teratologic hip dislocation?
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Pseudoacetabulum present at birth
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lf teratologic, what is the appropriate treatment?
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Early surgical intervention
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DDH is associated with what other packaging disorders?
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Metatarsus adductus
Rotary atlantoaxial subluxation |
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Diagnosis on physical exam: what are the two key tests for children 6 months of age or older?
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Barlow
Ortolani |
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What is the key test for children 6 months of age or older?
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Decreased abduction
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lf suspicious for DDH, radiographs should be obtained after what age?
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3 months
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What imaging study can be performed in younger children?
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Ultrasound of femoral head and acetabulum
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What is the normal acetabular index value?
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<25 degrees (>3O degrees is abnormal)
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What is the normal or angle?
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. >6O degrees
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What is the relationship between cx angle and acetabular index?
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Complementary (add up to 90 degrees)
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What is the normal center-edge angle?
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>25 degrees
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What does it measure?
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Measures subluxation
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What is the normal B angle? What does it measure?
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<55 degrees
Measures lateral contour |
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What is the role of arthrography?
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To check concentricity after closed reduction
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What is the normal size of the medial dye pool?
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<7 mm
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What is the normal labrum appearance on arthrography?
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"Rose thorn"
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If the labrum is infolded, what is it referred to as?
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Neolimbus
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What is the treatment algorithm based on age at diagnosis?
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<6 months: Pavlik harness
6 to 18 months: closed reduction >18 months to 3 years: open femoral derotation osteotomy >3 years to 8 years: femoral derotation osteotomy and acetabular osteotomy >8 years: if bilateral, leave alone until THA as adult |
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When should reduction or osteotomy be considered in children over 8 years of age?
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Unilateral dislocation
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Can the Pavlik harness be used in teratologic hip dislocations?
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No
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Why?
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Requires normal muscle function
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What are the two components of the desired position of the hip in the Pavlik harness?
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100 degrees flexion
Mild abduction (45 degrees) |
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What do the anterior straps control?
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Hip flexion
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What do the posterior straps control?
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Hip abduction
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If 45 degrees of abduction cannot be easily obtained, what procedure should be considered?
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Adductor tenotomy
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What is a possible consequence of placing the hips into excessive flexion?
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Femoral nerve palsy
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What vessel is associated with avascular necrosis (AVN) after Pavlik harness wear?
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Medial femoral circumflex (posterosuperior retinacular
artery) |
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How long after initiation of treatment should the hip be reimaged in Pavlik harness?
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2 weeks
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What two steps should be taken if the reduction is unsatisfactory at that time?
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Discontinue Pavlik treatment
Closed or open reduction when child is old enough |
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What is the usual surgical approach for open reduction?
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Anterior
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Why?
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Decreased risk to medial femora circumflex artery
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What is the other major advantage of the anterior approach?
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All structures accessible
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In patients of what age is the medial approach preferred?
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Under 2 years
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Through what approach can a femoral shortening be performed?
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A separate lateral approach
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What is the major risk of open or closed reduction?
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AVN
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What two structures are not accessible medially?
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Acetabular roof (including labrum)
Superior hip capsule |
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What two procedures cannot be performed through a medial approach?
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Capsular plication
Secondary bone procedures |
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What is the treatment if an inverted labrum is encountered when performing open reduction through the anterior approach?
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Make radial cuts
Do not excise labrum |
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What is the end result of lateral growth arrest due to AVN?
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Coxa valga
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What are the two prerequisites for acetabular osteotomy?
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Congruent reduction
Reasonable femoral sphericity |
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What study may be predictive of outcome?
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Functional x-rays (abduction/internal rotation)
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What three osteotomies are appropriate if the tri-radiate cartilage is open?
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Salter
Pemberton Dega |
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What two osteotomies are appropriate in the older child?
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Steel (triple)
Ganz |
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What two osteotomies are appropriate as salvage procedures?
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Shelf
Chiari |
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A Salter osteotomy enhances coverage where?
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Superior and lateral
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Does it medialize or lateralize the acetabulum?
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Lateralize
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What effect does it have on joint reaction force?
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Increased
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What is the age limit for Salter osteotomy?
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Less than 8 years of age to rotate through symphysis
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How is extremity length affected?
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May lengthen 1 cm
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On what structure does a Pemberton osteotomy bend?
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Triradiate cartilage
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What is the resultant effect?
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Reduces acetabular volume
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In what two situations is a Dega osteotomy appropriate?
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Paralytic dislocation
Posterior deficiency |
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What is a Steel osteotomy?
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Salter plus osteotomies of rami
Also known as triple |
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For whom is a Steel osteotomy indicated?
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Older children who cannot rotate through symphysis
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What is a Ganz osteotomy?
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Periacetabular osteotomy
Leaves posterior column intact Allows more rapid weightbearing |
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What osteotomy has greatest potential for increased coverage?
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Ganz
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Salvage procedures rely on what change taking place?
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Tissue metaplasia
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What is the disadvantage of a Chiari procedure?
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Shoitens leg by medializing hip
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What osteotomy is an option for adults?
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Ganz
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What osteotomy leaves medial wall in place and redirects acetabulum?
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Dial
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How does it compare with others?
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Others rotate teardrop also
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With what system is residual hip dysplasia classified?
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Crowe
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What is the Crowe system based on?
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Degree of uncoverage
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Where is the dysplastic acetabulum deficient?
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Anteriorly
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What is its size?
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Small
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A characteristic of the dysplastic femur is coxa _?
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Valga
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What is the characteristic anteversion?
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Excess
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What is the characteristic canal size?
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Small
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What type of femoral arthroplasty component is generally required?
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Modular
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How much lengthening is tolerated before risk of developing CPN (common peroneal nerve) palsy
increases significantly? |
2 cm
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Sciatic nerve palsy generally occurs at what degree of lengthening?
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5 cm
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lf lengthening >2 cm, what procedure should be considered?
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Femoral shortening
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