AVN

1. By
Dr Salihi Abdulmalik
National Orthopaedic Hospital Dala-Kano
2nd March, 2021

2.  Introduction
 Epidemiology
 Aetiology
 Pathogenesis
 Sites
 Clinical features
 Investigations
 Treatment
 Complications
 Conclusion

3.  Avascular necrosis is death of bone from
deficient blood supply
 Aseptic necrosis=osteonecrosis=ischemic
necrosis
 Bone death is irreversible

4.  Femoral head
 Scaphoid
 Talus
 Humeral head
 Radial head
 Humeral capitellum
 Medial femoral condyle
 Lunate (Kienbock’s disease)
 Navicula (Kohler’s disease)

5.  Head of femur
◦ 30-50 years
◦ M>F
◦ SCD M:F 1
◦ 10-18% of THR
◦ 50-80% of cases is bilateral
◦ 3% of patients have multifocal

6.  Idiopathic
 Traumatic
◦ Scaphoid
◦ Talus
◦ Femoral head
 Non traumatic
◦ Extraosseous
◦ intraosseous

8.  Hip dislocation
◦ 2-40%
◦ 2-10% if reduced witihin 6 hours
 Femoral head # (75-100%)
 #NOF
◦ Basicervical (50%)
◦ Cervicotrochanteric (25%)
 Acetabular #
 SUFE

9.  Extraosseous
◦ Intravascular
◦ extravascular
 Intraosseous
◦ Intravascular
◦ Extravascular

10.  Extravascular
◦ Trauma
 intravascular
◦ Caisson’s disease
◦ Vasculitis (Raynauds
disease
◦

11.  Extravascular
◦ Steroid
◦ Alcohol
◦ Compartment
syndrome
◦ Gauchers disease
 Intravascular
◦ SCD
◦ Steroid
◦ Caisson’s disease
◦ Fat emboli
(hyperlipidemia –
alcohol)

12.  Infection
 Ionising radiation
 Perthes disease
 SLE

13.  No advantitia layer
in the vascular
sinusoid
 Close compartment
◦ Venous
stasis/retrograde
arteriolar stoppage
◦ Intravascular
thrombosis
◦ Sinusoid
compression from
marrow swelling

14.  Asymptomatic
 Pain
 Click in the joint
 limp
 Stiffness
 Deformity

15.  Features of possible aetiology
 Antalgic gait
 Positive trendelenburg sign
 LLD
 Decrease ROM
 Sectoral sign

16.  Plain radiograph
◦ Seldom seen before 3 months after onset of
necrosis
◦ Demineralization – osteopenia
◦ Reactive new bone formation – sclerosis
◦ Crescent sign – subchondral #
◦ Irregularity on the head/flattenning/collapse
◦ ?Joint space

18.  MRI
◦ Most sensitive
◦ Focal lesion in anteriorsuperior portion of the
femoral head, well demarcated

21.  CT scan
 Bone scan
 Haemodynamic fucntion
◦ Intraosseous pressure
◦ Canular in metaphysis
◦ Measure at rest and after rapid ingestion of saline
◦ Normal
 10-20mmhg at rest
 Raise by 15mmhg
◦ AVN
 Both can be increased by 3-4 fold

22.  Hb genotype
 FBC
 ESR

23.  Ficat and Arlet
 ARCO
 Shimuzu
 University of Pennsylvania
 Ohzono classification

24.  Stage 1 (pre radiographic)
◦ Normal x ray
◦ MRI
◦ Intraosseous pressure
◦ Histology
 Stage 2 (pre collapse)
◦ Subchondral sclerosis/cysts
◦ Diffuse osteopenia

25.  Stage 3 (early collapse)
◦ Crescent sign
◦ Irregularity of femoral head
 Stage 4 (OA)
◦ Flattened/collapse head
◦ Joint space affectation

27.  Based on MRI images
 Defines the extent, location and intensity of
the abnormal segment
 Findings suggested that extent of ischemic
segment is determined at the outset and does
not progress

29. Shimuzu Extent of
femoral
head
affectation
Weight
bearing
area
affected
Probability
of head
collapse
within 3
years
Likely Rx
Grade I < ¼ Medial 1/3 Rarely Symptomati
c Rx,
monitor
Grade II Upto 1/2 1/3 to 2/3 30% 1. Core
decompress
ion
2.
Decompress
ion and
bone
grafting
Grade III >1/2 >2/3 70% Osteotomy
Hemiarthro
plasty

30.  Prompt reduction of dislocations/#s
 Use of steroids when necessary and adequtely
 Prevent crisis in SCD
 Prompt and adequate treatment of bone/joint
infections
 Gradual decompression of divers

31.  Determinant factors
◦ Involved bone
◦ Part of the involved bone
◦ Extent of necrotic segment
◦ Patient’s age
◦ Aetiological agent persistent?
◦ General medical background

32.  Non operative
◦ Waiting policy
 Non weight bearing areas
 Pain control
 Modification of activities
◦ Bisphosphonate

33.  Operative
◦ Joint preserving surgery
 Core decompression
 Bone grafting
 Osteotomies
◦ Joint replacing surgery
 Hemiarthroplasty
 THR
◦ Others
 Resection arthroplasty
 Arthrodesis

34.  Effective symptomatic release in all stages
 Reduces intramedullary pressure
 Removal of necrotic bone
 Aid revascularization
 Prevent additional ischemic events

35.  Ficat and Arlet I and II
 8 to 10mm diameter core track is created
through lateral cortical window
 Protect weight bearing for 6 weeks

36.  For Ficat and Arlet I and II
 Removal of the diseased femoral head
segment and its replacement with bone graft

37.  Redirectional
 Valgus or varus osteotomies combined with
flexion or extension

38.  Hemiarthroplasty
 THR

39.  Salvage procedure
 Failed non operative treatment with
contraindication for arthroplasty
 Relieves pain
 Position
◦ Adduction 0-5
◦ Flexion 25-30
◦ External rotation 0 -15

40.  AVN affects both children and adult
 Pain and subsequent joint collapse
 Treatment ranges from non operative to
arthroplasty

41. Thank you for listening