Avascular Necrosis (AVN)

AVN

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

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

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

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

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 Epidemiology

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

7. Blood supply to femoral head

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

9. Extraosseous Intravascular extravascular Intraosseous Intravascular Extravascular Non traumatic

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

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

12. Infection Ionising radiation Perthes disease SLE Others

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

14. Asymptomatic Pain Click in the joint limp Stiffness Deformity Clinical features

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

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 Investigations

17. Radiographs

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

19. MRI

20. 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 Investigations

21. Hb genotype FBC ESR Investigations

22. Ficat and Arlet ARCO Shimuzu University of Pennsylvania Ohzono classification Staging

23. Stage 1 (pre radiographic) Normal x ray MRI Intraosseous pressure Histology Stage 2 (pre collapse) Subchondral sclerosis/cysts Diffuse osteopenia Ficat and Arlet staging

24. Stage 3 (early collapse) Crescent sign Irregularity of femoral head Stage 4 (OA) Flattened/collapse head Joint space affectation Ficat and Arlet staging

25. 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 Shimuzu classification

26. Shimuzu

27. Shimuzu Extent of f emoral head affectation Weight bearing area affected Probability of head collapse within 3 years Likely Rx Grade I < ¼ Medial 1/3 Rarely Symptomatic Rx, monitor Grade II Upto 1/2 1/3 to 2/3 30% 1. Core decompression 2. Decompression and bone grafting Grade III >1/2 >2/3 70% Osteotomy Hemiarthroplasty THR

28. 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 Prevention

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

30. Non operative Waiting policy Non weight bearing areas Pain control Modification of activities Bisphosphonate Treatment

31. Operative Joint preserving surgery Core decompression Bone grafting Osteotomies Joint replacing surgery Hemiarthroplasty THR Others Resection arthroplasty Arthrodesis Treatment

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

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

34. For Ficat and Arlet I and II Removal of the diseased femoral head segment and its replacement with bone graft Bone grafting

35. Redirectional Valgus or varus osteotomies combined with flexion or extension Osteotomies

36. Hemiarthroplasty THR Arthroplasty

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

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

39. Thank you for listening