Paediatric knee

Question 1

What is osteochondritis dissecans?

Answer 1

• A pathologic lesion affecting the articular cartilage and subchondral bone w a variable clinical patterns
• Juvenile form
  
  • occurs 10-15 while physis open
• Adult form ( skeletal mature)
• location
  
  • knee
    
    • _posterolateral aspect of Medial femoral condyle 7_0%
  • capitellum of humerus
  • talus

Question 2

What is aetiology of osteochondritis dissecans?

Answer 2

• Hereditary
• Traumatic
• vascular
  
  • cause of adult form
• pathoanatomical cascade
  
  • softening of overlying casrtilage w intact artcular surface
  • early articular cartilage separation
  • partial detachment of lesion
  • osteochondral separation w loose bodies

Question 3

What is the prognosis of osteochondritis dissecans juvenile and adult form?

Answer 3

• Juvenile
  
  • younger age correlates with better prognosis
  • opend distal femoral physes best predictor of non op mx
• location
  
  • **lesions in lateral femoral condyle & patella = **poorer prognosis
• appearance
  
  • synovial fluid behind lesion on MRI = poor prognosis
• Adult
• worse prognosis
• usually symptomatic & -> DJD if left untx

Question 4

What is the classification of osteochondritis dissecans?

Answer 4

• Clanton
• Type 1= depressed osteochondral fx
• type 2= fragment attached by osseous bridge
• type 3= detached non-displaced fragment
• type 4= displaced fracture

Question 5

What is the presentation of a pt with osteochondritis dissecans?

Answer 5

Symptoms

• Pain
  
  • Activity related, vague and poorely localised
• Recurrent effusions

O/E

• Localised tenderness
• stiffness
• swelling
• Wilson’ test
  
  • Pain on internal rotation during extension of the knee between 90^o and 30^o then relief w tibial external rotation

Question 6

What is seen on imaging of osteochondritis dissecans?

Answer 6

Xray

• lytic area in medial femoral condyle

MRI

• Size of lesion
• signal intensity surrounding the lesion
• presence of loose bodies

Question 7

What is the tx of osteochondritis dissecans?

Answer 7

Non operative

• restricted weight bearing & bracing
  
  • stable lesions in children open physis
  • 50-75% will heal without fragmentation

​Operative

• Diagnostic arthroscopy
• Microfracture
  
  • ​stable lesion
  • tap awl to depth of 1-1.5cm below articular depth
  • -> formation of fibrocartilage tissue
  • improves outcomes in skeletaly immature pts
  • NWB 4-6 wks with CPM
• Fixation of unstable lesion >2cm
  
  • 85% healing rates in juvenile
  • cannulated screw/herbert screw/ k wire
• **Chondral resurfacing **
  
  • Lesions >2cmx2cm
  • osteochondral grafting
  • arthroscopy if lesion < 3cm, arthrotomy if >3cm
  • allograft plugs
  • Osteochondral autograft transferal system = OATS/ mosacioplasty
• Knee arthroplasty
  
  • pts > 60yrs

Question 8

What is Osgood schlatter’s disease?

Answer 8

• Osteochondrosis or traction apophysitis of tibial tubercle
• >boys
• 12-15y boys and girls 8-12 yrs
• location
  
  • bilateral 20-30%
• Risk factors
  
  • jumpers or sprinters
• Pathophysiolgy
  
  • stress from extensor mechanism
• Prognosis
  
  • self limiting but doesn’t reolve until growth has halted

Question 9

Describe the anatomy of the tibial tubercle?

Answer 9

• A secondary ossification centre
• <11 yrs tubercle is cartilaginous
• age 11-14 apophysis forms
• age14-18 apophysis fuses with tibial epiphysis
• >18 yrs epiphysis and apophysis is fused to rest of tibia

Question 10

What is seen on imaging the tibial tubercle?

Answer 10

Xray

• Irregularity and fragmentation

MRI

• soft tissue swelling
• thickened oedema of inferior patella tendon
• fragmentation and irregularity of ossification centre

Question 11

What is the presentation of Osgood shlatter’s disease?

Answer 11

• Pain on anterior aspect of knee
• exacerbated by knee

O/E

• Enlarged tibial tubercle
• tenderness over tubercle
• pain on resisted knee extension

Question 12

What is the tx of Osgood shlatter’s disease?

Answer 12

Non operative

• Nsaids, rest, ice, activity modification, strapping/sleeves to decrease tension on the apophysitis and quad strengthening
  
  • first line of tx
  • 90% have complete resolution
• ​cast immobilisation 6 wks
  
  • ​severe symptoms not responding to above
  • can -> quads wasting

Operative

• Osscile excision
  
  • refractory cases 10%
  • in skeletally mature pts with ongoing symptoms

Question 13

What is Sinding- Larson-Johansson syndrome?

Answer 13

• Overuse injury causing anterior knee pain at the inferior pole of patella
• more common in adolescence
• location
  
  • patellar tendon insertion at inferior pole of patella
• pathphysiology
  
  • chronic injury
  • similar pathogenesis to Osgood-schlatter’s disease
  • overuse causes traction apophysitis

Question 14

What is the classification of Sinding- Larson-Johansson syndrome?

Answer 14

• Blazina
• Stage 1- pain occurs after activity
• Stage 2- pain present while preforming activity and persists after activity
• Stage 3- pain affecting/limiting function during activity

Question 15

What is the presentation of Sinding- Larson-Johansson syndrome?

Answer 15

• Insidious onset of pain on anterior aspect of knee after or during activity

O/E

• tenderness over inferior patella
• swelling

Question 16

What is seen on imaging of Sinding- Larson-Johansson syndrome?

Answer 16

• Xray
  
  • Normal
  • spur to inferior pole
• MRI
  
  • Inflammation best seen on T2 sagitals
  • bony spurs on t1

Question 17

What is the tx of Sinding- Larson-Johansson syndrome?

Answer 17

Non operative

• activity modification, nsaids, physio
  
  • mainstay of tx
  • usually self limiting process

Operative

• Debridement of damaged tissue/stimulation of healing response
  
  • ​if refractiory to consx tx