Paeds Hip (Complete) Flashcards
What are the risk factors for the development of DDH?
[Clinical Pediatrics 2015, Vol. 54(10) 921–928][Lovell and Winter]
- Female
- Feet first (breech)
- First born
- Family history
- Oligohydramnios
- Swaddling
- Caucasian
What hip is most commonly affected in DDH?
[Orthobullets]
Left hip (60%)
What are the examination findings in DDH?
[Miller’s, 6th ed.]
- Dislocated – Ortolani positive (early), Galleazzi sign
- Dislocatable – Barlow positive
- Subluxable – Barlow suggestive
- Other – asymmetric gluteal fold, decreased hip abduction (>3 months), wide perineum (bilateral dislocated hips)
What are the potential obstructions to obtaining a concentric reduction in DDH?
[Miller’s, 6th ed.]
- Iliopsoas tendon (creates hourglass capsule)
- Adductor tendon (limits abduction)
- Inverted labrum
- Contracted inferomedial capsule
- Transverse acetabular ligament
- Pulvinar
- Ligamentum teres
- Limbus (ridge of cartilage tissue that divides the acetabulum into a true and a false acetabulum)
When do you choose hip ultrasound over radiographs?
- Ultrasound prior to femoral head ossification (<6months)
- Radiographs following femoral head ossification (>6months)
Describe the ultrasound features to assess for when evaluating DDH?
- Lines drawn parallel to the iliac wing, roof of acetabulum, labrum
- Alpha angle
- Formed between line parallel to ilium and acetabular roof
- Normal = >60
- Beta angle
- Formed between line parallel to ilium and labrum
- .Normal = <55
- Femoral head should be bisected by line parallel to ilium
- Morin index = percentage of the head covered by the acetabulum (below the ilium line)
- Calculated as the width of the femoral head below the line divided by the width of the femoral head
- Normal = >50%
- Borderline = 46-50%
- Abnormal = <46%
Describe the radiographic features of DDH
- Delayed ossification of femoral head (small)
- Hilgenreiner’s line = horizontal line through the right and left triradiate cartilage
* Normal femoral head should be below line - Perkins line = line perpendicular to Hilgenreiner’s line passing through point at the lateral acetabular roof
* Normal femoral head lies medial to line - Shenton’s line = line along the inferior femoral neck and inferior superior pubic ramus
* Normal = smooth and unbroken - Acetabular index = line parallel to the acetabular roof forms angle with Hilgenreiner’s line
- Normal = <25 after 6 months of age
- (24 at 24)
Describe the application of the Pavlik harness
- Hip flexion 100+/-10 degrees
* Controlled by anterior strap – in line with anterior axillary line - Hip abduction in the safe zone (between maximum abduction which places head at risk of AVN and adduction point where hip dislocates/subluxes)
- Controlled by the posterior strap – at level of scapula
- Straps should not force abduction, rather should prevent adduction beyond neutral
- Chest halter strap at nipple level
What are the complications associated with Pavlik harness use?
[Lovell and Winter]
- Transient femoral nerve palsy (excessive flexion)
- Femoral head AVN (excessive abduction)
* Due to compression of the posterosuperior retinacular branch of the medial femoral circumflex artery - Brachial plexus neuropathy (compression by shoulder straps)
- Pavlik harness disease
- Persistent pavlik harness use despite unsuccessful reduction resulting in pathologic changes – damage to femoral head, acetabular cartilage
- “Prolonged positioning of the dislocated hip in flexion and abduction that potentiates dysplasia, particularly of the posterolateral acetabulum, and increases the difficulty of obtaining a stable closed reduction.” [Jones et al. J Pediatr Orthop. 2018 Jul; 38(6): 297–304.]
- Skin breakdown (groin and popliteal fossa)
- Inferior dislocation (excessive flexion)
What are contraindications to Pavlik Harness use?
[World J Orthop. 2013 Apr 18; 4(2): 32–41]
- Major muscle imbalance (eg. myelomeningocele – L2 to L4 functional level)
- Major stiffness (eg. arthrogryposis)
- Ligamentous laxity (eg. Ehlers-Danlos syndrome)
What is the recommended DDH treatment for patients <6 months and >6 months?
[Lovell and Winter]
1.Neonate – 6 months
- First line = Pavlik Harness
- 95% resolution of hip instability in Ortolani positive hips maintained in Pavlik for 6 weeks
- >50% failure rate if used in patients > 6 months
- Harness applied with followup in one week to confirm reduction (confirmation by clinical exam and US both acceptable) followed by weekly followup to adjust straps and confirm reduction
- Duration of treatment variable
- Minimum 6 weeks of full time use (23 hours a day)
- Usually followed by period of weaning
- One algorithm treats until hip normal by US (Graf classification type I) [J Child Orthop. 2018 Aug 1; 12(4): 308–316.]
- If not reduced after 2 weeks – discontinue use and consider closed/open reduction at 4-6 months
- 6 months – 4 years
* First line = Closed reduction +/- adductor tenotomy- Closed reduction performed in OR
- Reduction achieved with flexion, abduction, longitudinal traction, slight posterior pressure to GT
- Arthrogram used to assess quality of reduction (medial dye pool <5mm or <16% of the width of the femoral head indicates concentric reduction)
- Adductor tenotomy can be performed to widen the “safe zone”
- Consider if narrow “safe zone” of less than 40°
- Hip spica cast applied with 100° flexion and abduction in the “safe zone” (<55°) with molding posterior to GT
- 100° of flexion and 40–50° of abduction referred to as the “human position” of the hip
- Reduction is confirmed with CT (or MRI)
- Spica cast use for 3 months
- Cast change at 6 weeks – assess reduction, stability and hygiene purposes
- Followed by abduction brace fulltime for 4 weeks
- Followed by nighttime brace for 4 weeks
- Second line = open reduction
- Indicated in cases of failed closed reduction
- Technique:
- Smith-Peterson approach with modified “bikini” incision, adductor tenotomy, psoas recession, T capsulotomy, remove blocks toreduction, capsulorrhaphy (lateral leaf brought medial)
- Ligamentum teres is guide to true acetabulum
- Possible femoral shortening osteotomy if > age 3 or under tension after reduction
- Possible acetabular procedure if >18 months
- Spica cast is used for approximately 6 weeks with immobilization in about 30 degrees of abduction, 30 degrees of flexion, and 30 degrees of internal rotation
- Closed reduction performed in OR
What are advantages and disadvantages of medial vs. anterior approach for open reduction?
[Orthobullets]
- Medial
- Advantages
- Can be done at <12months
- Directly addresses inferomedial blocks to reduction, less blood loss
- Disadvantages
- Cannot perform capsulorrhaphy or bony work, risk of AVN
- Note – Ludloff described interval between adductor longus and pectineus
- Anterior
- Advantages
- Performed at >12 months
- Less AVN risk
- Can perform capsulorrhaphy or bony work
What is the technique for administration of contrast dye to the hip for arthrogram?
Needle directed medial to lateral 45° to the thigh and 45° to the horizon aiming towards the ASIS
- Inject 1:1 ratio of saline:contrast
Recommended interventions of DDH based on age?
[JAAOS 2016;24:615-624]
- <6 months = Pavlik harness
- 6-12 months = closed reduction and spica casting
- Closed reduction, possible adductor tenotomy, hip arthrogram, spica casting, CT/MRI
- 12-18 months = open reduction
- Open reduction, adductor tenotomy/psoas recession, capsulorrhaphy, spica casting, CT/MRI
- 18 months – 3 years = open reduction and pelvic OR femoral osteotomy
- >3 years = open reduction and pelvic + femoral osteotomy
- Open reduction, adductor tenotomy/psoas recession, pelvic osteotomy, femoral shortening and derotation osteotomy, capsulorrhaphy, spica casting, CT/MRI
What is the role of femoral osteotomy in DDH?
[JAAOS 2016;24:615-624]
- Shortening of the femur reduces contact pressure on the femoral head thereby reducing the risk of osteonecrosis
- Derotation of the femur reduces the excessive anteversion
- Technique
- Performed through a lateral approach
- Subtrochanteric osteotomy just below level of LT
- Amount of shortening is determined by amount of overlap after femoral head reduced in the acetabulum
- Amount of derotation is determined by matching the opposite limb
What is the role of the pelvic osteotomy?
[JAAOS 2016;24:615-624]
Improves the stability of the open reduction, improves the coverage of the femoral head
- Type of osteotomy is based largely on surgeon preference
What are 4 radiographic markers used as the child grows to ensure that the reduction of DDH hip was successful?
[JAAOS 2016;24:615-624]
- Improvement in the acetabular index
- Sharp (not rounded) lateral border of the acetabulum
- Narrow teardrop
- Intact Shenton line
What radiographic criteria can help diagnosis of osteonecrosis after DDH reduction?
[JAAOS 2016;24:615-624]
- Failure of femoral head to ossify (or failure of an already present ossific nucleus to grow) within 1 year of reduction
- Broadening of the femoral neck
- Increased density of the femoral head (followed by fragmentation)
- Residual deformity after ossification is complete
What is the classification of osteonecrosis following treatment of DDH?
[JAAOS 2016;24:615-624]
Kalamchi and MacEwan
- Type I - alteration in the ossific nucleus
- Type II - lateral physeal damage
- Type III - central physeal damage
- Type IV - total damage to the head and physis
What are the risk factors for SCFE?
[Lovell and Winter][J Am Acad Orthop Surg 2006;14:666-679]
- Obesity (~50% are above the 95th percentile for weight)
- Boys
- Pacific Islanders
- African american
- Endocrinopathy (hypothyroidism, panhypopituitarism, growth hormone abnormalities, hypogonadism)
- Radiation to the proximal femur
- Renal osteodystrophy