Paediatrics

Question 1

Causes of limb length discrepancies

Answer 1

1. Bone: femur vs tibia shortening
2. Joint: DDH
3. General:
   - muscle hypertrophy on one side (nerve -NF, vessels - hemangiomas)
   - polio
4. Physiological
   - metatarsal adductors
   - tibial torsion
   - femoral anteversion
   - flat foot

biggest concern: undiagnosed DDH

Question 2

Approach to limping child

Answer 2

Painless: limb length discrepancies

Painful - divide by age grp
<3yo: infx or trauma (exclude NAI), distal tibial #

3-7yo:

• transient synovitis (commonest cause but diagnosis of exclusion)
• inflammatory arthritis
• growing pain (dx of exclusion): bone growth faster than rate of length increase for muscle and tendon, worse at end of day, relieved with massage, sleep
• leukemia

7-10yo:

• perthes dz
• transient synovitis

> 10yo:
- growing pains

Question 3

Developmental dysplasia of the hip (DDH)/ congenital dislocation of hip (CDH)
- RF

Answer 3

RF: girls>boys, left hip>right hip, bilateral in 20%

• family history: joint laxity, shallow acetabulum
• intrauterine malposition/ crowing: multiple pregnancies, oligohydramnios, fibroids, large baby, small bother, extended breech delivery
• post natal posture: carried with hip and knee fully extended

Question 4

Developmental dysplasia of the hip (DDH)/ congenital dislocation of hip (CDH)
- diagnosis

Answer 4

Newborn: positive Barlows and Ortolani

<3mth: ultrasound
high risk (hip laxity or hip clicks): US at 6w - not accurate if earlier (maternal hormones contribute to jt laxity)
- big alpha angle means hip held well

Beyond 3 m: clinical signs +x ray

• reduced hip abduction
• asymmetrical thigh skin creases
• galleazi test - femur shortening (also int rotated)
• trendelenburg/ waddling gait

Question 5

Explain the pathology of DDH

Answer 5

Acetabulum unusally shallow and roof slopes upward too steeply
(from dysplasia without displacement to drank dislocation)

femoral head displaced posteriorly and superiorly

reduction impeded by joint capsule and fibrocartilaginous labrum

Maturation of acetabulum and femoral epiphysis retarded > risk of OA due to head being non spherical (incorrect distribution of body weight)

Question 6

Ortolani vs Barlows

Answer 6

Barlows - test dislocatability
(flex hip and adduct, followed by posterior force in line of shaft of femur)

Ortolani - test reducibility
(flex hip to 90def and abduct, then apply pressure on greater trochanter and feel clunk and subsequent full abduction)

Question 7

What is perkin’s line

Answer 7

vertical line drawn along lateral most aspect of acetabular roof. Normally epiphysis should lie medial

Question 8

What is Hilgenreiner’s line?

Answer 8

horizontal line drawn thru superior aspect of triradiate cartilages. Normally epiphysis should lie below

Question 9

DDH x ray findings

Answer 9

• acetabulum: shallow + roof slopes upward steeply
• Femoral head: small and femoral head underdeveloped, displaced superiorly and posteriorly
• Shenton line broken
• head lateral to perkin line, superior to hilgenreiner line
• increased acetabular index (>30 deg)

Question 10

mgx of DDH

Answer 10

goal: concentrically reduced and stable hips with good acetabular cover

depends on age of diagnosis
0-6mths
- reducible: pavlik harness/ abduction splint for 6w
- irreducible: adductor tenotomy; closed reduction + hip spica

6-18mths- attempt closed reduction under anaesthesia (traction+gradual increase in abduction)
- else open reduction + plaster spica

> 18mths: less potential for acetabular remodelling

• open reduction
• acetabular and proximal femoral sx (salter osteotomy to provide acetabular cover)

Question 11

Pavlik harness positioning and what to avoid

Answer 11

human position: hip 100deg flexed, 50deg abducted

avoid frog position: hip abducted at 90deg (caused AVN of femoral head)

Question 12

cx of untreated DDH

Answer 12

• progressive deformity, disability, secondary hip OA
• trendelenburg gait - scoliosis
• bilateral: waddling gait, lordosis

Question 13

What is transient synovitis

- mgx

Answer 13

inflammation of synovium of hip joint, postulated due to URTI/ pharyngitis/ bronchitis or trauma

Diagnosis of exclusion

mgx:
- head, massage, bed rest
- NSAIDs
- rule out red flags

Question 14

Cx of septic arthritis

Answer 14

• complete destruction of articular cartilage and underlying epiphysis
• loss of adjacent growth plate
• joint dislocation

Question 15

mgx of septic arthritis

Answer 15

medical: IV abx
surgical:
- repeated percutaneous jt aspirations
- else, open drainage in OT

traction on hip/ splint in abduction until infection resolves

Question 16

what is the pathophysiology of perches dz

Answer 16

trauma/ non specific synovitis > effusion in hip joint > pressure on lateral epiphyseal vessels in retinacula > blood supply disturbed > AVN femoral head > collapse/ fragmentation/ healing/ remodelling

Question 17

Stages of perthes

Answer 17

1. ischemia of part of femoral head
2. revascularisation and repair
3. distortion and remodelling

Question 18

Mgx of torticollis

Answer 18

conservative (<1yo): physio

sx (>1yo): surgical release of SCM, traction, custom made collar in immediate post op period + aggressive post op physio