The overview of knee osteonecrosis SPONK vs. SOK Pathogenesis What are their differences? What are the latest treatment approaches?

1. In the name of GOD

2. Knee Osteonecrosis
Mohammadreza Razzaghof, MD MPH
Resident of Orthopedic Surgery
Joint Reconstruction Research Center
Tehran University of Medical Sciences

3. KNEE OSTEONECROSIS: OVERVIEW
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4. SPONK
SONK
Knee osteonecrosis
Post-arthroscopic ON
True ON
secondary ON
SOK

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7. Week 1 : Normal
Week 3 : Slight flattening
Week 10 : increased
flattening + subchondral
lucency
Month 4 : thin calcified
plated + sclerotic halo

9. Entities
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10. SPONK SOK
Vs.
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11. Pathogenesis
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12. SPONK
Unknown
etiology
(trauma??)
Subchondral
Fx
Bone
resorption &
remodeling
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13. SPONK
Yamamoto et al, JBJS, 2000
Takeda et al, JBJS, 2008
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14. SOK
Inciting
etiology
ischemia
True
necrosis
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15. SOK: inciting etiology
• ↑ intraosseous (IO) adipocyte size and proliferation
• ↑ IO pressure  ischemia
Corticosteroid, alcohol
• Bone marrow displacement
• ↑ IO pressure  ischemia
Gaucher, leukemia,
myeloproliferative
• Mechanical vessel occlusion
Emboli, Caisson, sickled
cell, thrombophilia
• vasoconstriction
Smoking
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16. SPONK SOK
Vs.
True ON
Not true ON
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17. History
SPONK
 >55 y/o
 3/1 : female
 Onset of pain: sudden
SOK
 <45 y/o
 SLE : female, alcohol : male
 Onset of pain: insidious
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18. Lesion
SPONK
 Bilaterality: <5%
 Other joints: No
 Location: epiphysis
 Condyle: one (90% femur, 10%
tibia)
 Both femur & tibia: No
SOK
 >80%
 >90%
 Epi/meta/diaphysis
 Multiple
 20%
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19. Associations
SPONK
 Associated factors:
None
 Associated diseases:
None
SOK
 Corticosteroids, alcohol, tobacco
 SLE, sickle cell, caisson,
Gaucher, thrombophilia,
hypofibrinolysis
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20. Pathology
SPONK
 Fibrotic bone
 healing fracture
SOK
 Necrotic bone
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21. Classification
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22. Koshino

24. KNEE OSTEONECROSIS: TREATMENT
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25. Treatment Approach
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26. Treatment: SPONK
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27. Treatment: SPONK
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28. SPONK: lesion size
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29. (Aglietti et al, JBJS, 1983)
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(Lotke et al, CORR, 1982)

30. (Mont et al, JBJS, 2000)

31. Treatment: SPONK
Non-operative
 Small lesion (< 3.5 cm2)
 Medium ??
 Stage I, II Ficat
– Pre-collapse
Operative
 Medium??
 Large lesion (>5 cm2)
 Stage III, IV Ficat
 Failure of non-operative Tx
– After 3 months
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32. Treatment: SPONK
Non-operative
 Non-weight bearing
 Protected weight bearing
 Knee brace
 NSAID + Analgesic
 Bisphosphonate
 6-12 weeks  evaluation
– Clinical + radiological
Operative
 Joint preserving
– Arthroscopic
debridement/microfracture
– Core decompression
– High tibial osteotomy
– Osteochondral autograft
– Subchondroplasty
 Arthroplasty
– UKA vs. TKA
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33. Treatment: SPONK
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34. (Zywiel et al, Orth Clin North Am, 2009)

36. Treatment: SPONK
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37. Treatment: SPONK
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38. Treatment: SPONK
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39. Treatment: SOK
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40. Treatment: SOK
Non-operative
 Small & medium size
 Metaphyseal
 Ficat I, II (Pre-collapse)
 Ficat III ??
Operative
 Failure of non-operative Tx
– After 3-6 months
 Joint preserving
– Ficat I, II
 Arthroplasty
– Ficat III, IV
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41. Treatment: SOK
Non-operative
 Protected weight bearing
 Weight reduction
 Knee muscle strengthening
 NSAID + Analgesic
 Bisphosphonate
Operative
 Joint preserving
– Core decompression
– Bone grafting
– Articular surface reconstruction:
auto/allogenic osteochondral graft
– Local debridement + osteoprogenitor
cell grafting
– subchondral bone marrow concentrate
injection
 Arthroplasty
– UKA vs. TKA
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42. Treatment: SOK
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43. (Zywiel et al, Orth Clin North Am, 2009)

44. Treatment: SOK
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45. Treatment: SOK
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46. Treatment: SOK
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5-year f/u

47. Treatment: SOK
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48. Gortz et al, CORR, 2010

49. 3-month f/u
Gortz et al, CORR, 2010

50. Pre-op

51. 15-year f/u
Post-op

52. Pre-op 3-month F/U 15-year F/U

53. Treatment: SOK
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54. SOK lesion following
corticosteroid use for
SLE
Pre-op
Pre-op
Boontanapibul et al, JOA, 2020

55. Local debridement + enriched osteoprogenitor cell
grafting (Boontanapibul et al, JOA, 2020)
Immediate
postop
6 weeks
f/u
3 years
f/u

56. Treatment: SOK
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57. Hernigou et al, IO, 2018

58. Hernigou et al, IO, 2018
Pre-op 10 years f/u

59. Treatment: SOK
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60. Treatment: SOK
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61. THANKS FOR YOUR ATTENTION… Kashan, Iran
Tabataba’ei House