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Flashcards in Vascular and Growth Disorders Deck (14)
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1

Osteonecrosis 

Death of the osseus cellulr components and marrow due to impaired blood supply. 

Epiphyseal necrosis = avascular necrosis 

Metaphyseal/Diaphysis necrosis = bone infarct 

Causes 

  • Fat emboli 
  • Septic emboli from infection 
  • Caissons disease (nitrogen gas emboli)
  • Fat deposition in arteries 
    • Hyperlidemia, Alcholism, Cushing's  Disease 
  • Collagen disorders 
    • RA, SLE, Vasculitis, Increased corticosteroid use 
  • Vascular
    • Sickle cell anaemia, Pregnancy (pressure from uterus impairs venous drainage)
  • Radiation 
  • Gout
  • Gaucher's Disease 

Pathogenesis (4 phases)

  • Avascular: Loss of blood supply and bone death 
    • Joint swelling, loss of bone density, collapse of bone 
  • ​Revascularisation: Infiltration og new blood vessels, resorption of dead bone and deposition of new bone 
    • Fragmentation, Decreased size of epiphysis, flattening, sclerosis 
  • Repair and Remodelling: Increased bone deposition, new bone easily remolded - may lead to deformity 
    • Sclerosis 
  • Deformity: Dependent on the amount of compressive force through the joint during healing 

Radiographic Signs 

  • Plain films has poor sensitivity and may take months before visible on x-ray/CT
  • Increased joint space due to intracapsular swelling 
  • Ill-defined mottling of trabecular pattern within first weeks to months 
  • Bone scans will show changes within weeks 
  • MRI will show changes from days to weeks 
    • Low signal intenisty in segmental pattern 
  • Collpase of articular cortex 
  • Subchondral fracture 
    • Weakneing of subchiondral bone - fracture seperates cortex from underlying cancellous bone = cresent sign 
  • Fragmentation 
  • Decreased bone size 
  • Sclerosis and subchondral cysts 
  • Boney deformity  

 

2

Avascular Necrosis: Legg-Calve-Perthes Disease  

Femoral capital epiphysis 

Demographics 

  • 5:1 male
  • 3 to 12 years; peak incidence 5 to 7 years
  • Prognosis better for younger age group (<4yrs), worsens with later onset
  • Bilateral in 10% of cases (rare in female)
  • Familial incidence in approx. 6 – 12%
  • Rare in black children

Clinical Features 

  • Vague groin pain, possibly to anteromedial knee
  • Possible limp
  • Pain on abduction and internal rotation
  • Chronic: atrophy of thigh muscles

Pathogenesis 

  • The femoral head vascular supply is derived from 3 primary sources:
    • Foveal vessels penetrating through ligamentum teres
    • Superior and inferior epiphyseal vessels from medial and lateral circumflex branches of profunda femoris
    • Metaphyseal vessels from the bone marrow
  • The femoral head epiphysis is vulnerable to vascular compromise between the ages of 4 – 7 yrs, because:
    • Foveal and metaphyseal vessels are negligible at this age
    • The majority of blood supply comes from epiphyseal vessels, especially the lateral group

Radiographic Features 

Early radiographic signs (avascular phase) (0 – 12 months)

  • Joint effusion – increased medial joint space
  • Waldenstrom’s sign
    • (Waldenström sign is the increased distance between the pelvic teardrop and the femoral head. It is a highly specific sign of a hip joint effusion.)
  • Decreased bone density
  • Small femoral head epiphysis

Later changes: Revascularization phase (6 months – 4 years)

  • Articular collapse
  • Subchondral fracture: crescent sign
  • Fragmentation & separation of fragments
  • Flattened small epiphysis
  • Homogenous sclerosis (snowcap sign)
  • Patchy sclerosis
  • Widening & shortening of femoral neck

Repair-remodelling phase (1-2 years)

  • Sclerosis as new bone laid down
  • Fragments reform then migrate back into shape
  • Remodelling of epiphysis and reconstitution of density

Deformity

  • Flattened femoral head (mushroom cap deformity)
  • Widened and shortened femoral neck
  • Enlarged greater trochanter
  • Coxa vara deformity
  • Shallow acetabular cup
  • Secondary OA changes

3

Spontaneous Osteonecrosis of the Knee (SONK)

  • Slightly inc female
  • > 60yrs
  • Sudden onset of pain
  • Radiographic signs unremarkable initially
  • Unknown aetiology
  • Medial femoral condyle – weight bearing surface
  • Similar to DJD but:
    • Only in femur
    • No joint space loss
    • No osteophytes
    • Crescent sign

 

4

Freiberg's Disease 

  • Females 5:1
  • 13 – 18yrs
  • Pain, swelling on activity
  • Usually 2nd metatarsal head
  • Note: flattening of 3rd MT head in this image

5

Keinboch's Disease 

  • Avascular necrosis of lunate
  • Male 9:1
  • 20 -40yrs
  • Possible history of acute/chronic trauma
  • Worsening pain and disability
  • Increased with negative ulnar variance

6

Preiser’s Disease

Note increased density of proximal portion of scaphoid due to avascular necrosis

 

7

Kohler’s Disease

  • Navicular
  • Male predominant
  • 4 – 10yrs
  • Local pain and swelling
  • Patchy sclerosis
  • Collapse and fragmentation
  • Bone scan differentiates from growth variation

8

Truamatic Epiphyseal Injuries: Osgood-Schlatter’s Disease

  • Increased males, 11-15yrs, traumatic history, bilateral 25- 50%
  • Localised pain and tenderness tibial tubercle
  • Clinical diagnosis
  • Not osteonecrosis – inflammatory process

 

9

Traumatic Epiphyseal Injuries: Scheuermann’s Disease

  • Not osteonecrosis – possible traumatic growth arrest or endplate fractures
  • Active in adolescent years
  • 13 – 17yrs
  • Slightly males
  • Asymptomatic - painful
  • “Tiredness” in back
  • Poor posture
  •  Adolescent kyphosis
  • 8% population
    • (7.19% of clinic patients)

Radiographic Features 

  • T6 – L2 most common
  • Radiographic diagnosis:
    • 3 consecutive segments with at least 2 of:
      • Schmorl’s nodes / endplate irregularities
      • Anterior wedging of 5o or more
      • Increased A-P diameter
      • Increased kyphosis
    • Loss of disc height

10

Traumatic Epiphyseal Injuries: Post Scheuermann’s Disease

  • Only active during adolescent years
  • Radiographic changes maintained
    • Hyperkyphosis
    • Irregular endplates/multiple schmorl’s nodes/limbic bones
    • Loss of disc height
    • Anterior wedging
    • Sagittal elongation of body
  • Premature disc degeneration

11

Osteochondritis Dissecans 

  • Small necrotic fragment subchondral bone
  • Unknown etiology
  • Trauma?
  • Shearing, rotary or tangentially applied forces involved
  • Occasional acute traumatic episode
  • Primary vascular occlusion?
  • Hereditary tendency?
  • Males 11 – 20 yrs
  • Asymptomatic, or intermittent locking & giving way, swelling
  • Knee, ankle, elbow, hip
  • Small dense fragment of detached bone within radiolucent defect with sclerotic concave border
  • Fragment may detach

12

Growth Varients of the Epiphysis 

13

Sever's Disease 

  • Not avascular necrosis of calcaneus
  • Mistaken diagnosis of avascular necrosis of calcaneus due to radiographic appearance in children/adolescents presenting with heel pain
  • Normal calcaneus, achilles traction apophysitis causing heel pain

14

Sinding-Larsen-Johansson

  • Inc male 10-14yrs
  • Swelling, pain, inability to run
  • Traction apophysitis inferior patella