Download MBBS Orthopaedics PPT 4 Avascular Necrosis Lecture Notes

Avascular Necrosis

Learning Objectives

--- Content provided by FirstRanker.com ---

? Atraumatic /Traumatic AVN
? Understand the pathology of AVN
? Progression of disease
? Classification of Hip AVN
? Principles of treatment

--- Content provided by FirstRanker.com ---

27 years old ,pain right groin

? Non smoker, occasional alcohol intake, no medical history

--- Content provided by FirstRanker.com ---

? On examination.

? No Tenderness

? Restricted internal rotation ,painful

--- Content provided by FirstRanker.com ---

? No limp

? CBC Normal, Rheumatoid factor ?ve, ESR 18mm,CRP -6

--- Content provided by FirstRanker.com ---

Radiographs
Q1 Which of the following is an inappropriate

diagnosis?

--- Content provided by FirstRanker.com ---

a) Early Sero-Negative Rheumatoid arthritis
b) Avascular necrosis right hip
c) Tubercular arthritis right hip
d) Torn acetabular labrum

--- Content provided by FirstRanker.com ---

Q 2 The most appropriate investigation for

him is?

a) Tc 99 bone scan

--- Content provided by FirstRanker.com ---

b) MRI scan
c) MARS MRI
d) Contrast enhanced CT Scan
Q3 This is classifiable as Ficat-Arlet-

--- Content provided by FirstRanker.com ---

a) Stage 1
b) Stage 2
c) Stage 3
d) Stage 4

--- Content provided by FirstRanker.com ---

Q 4 The most appropriate treatment ?

a) Non operative with follow up MRI at 6 weeks
b) Non weight bearing and analgesics
c) Bed rest, traction and analgesics

--- Content provided by FirstRanker.com ---

d) Core decompression
Q 5 The patient comes after 2 years and has severe pain in his

hip, decreased ROM and a pronounced limp. Radiographs

--- Content provided by FirstRanker.com ---

reveal collapse of the head with decreased joint space

suggestive of secondary OA. The appropriate management is-

a) Arthroscopic debridement and irrigation

--- Content provided by FirstRanker.com ---

b) Osteochondral grafting
c) Bipolar hip arthroplasty
d) Total hip arthroplasty

Overview

--- Content provided by FirstRanker.com ---

? AVN is a major cause of hip pain
? Traumatic/Atraumatic in etiology
? Evaluation is difficult
? Treatment is hip salvage/Replacement

--- Content provided by FirstRanker.com ---

? Other common areas are ?Humerus, scaphoid, talus and distal femur
Avascular necrosis- Traumatic

? Femoral neck fractures- severance of the blood supply to the femoral

--- Content provided by FirstRanker.com ---

head.

? The capitulum
? Femoral condyles
? Proximal parts of the scaphoid and talus.

--- Content provided by FirstRanker.com ---

Distant parts of the bone's vascular territory
Largely enclosed by cartilage- restricted access to local

blood vessels.

--- Content provided by FirstRanker.com ---

TRAUMATIC OSTEONECROSIS

? Fractures and dislocations of the hip

? Tear of retinacular vessels supplying the femoral head

--- Content provided by FirstRanker.com ---

? Displaced fractures of the femoral neck ? AVN 20%.


fractures of the scaphoid and talus- AVN

--- Content provided by FirstRanker.com ---

? Principal vessels enter their distal ends
? Intraosseous course from distal to proximal.

Closed compartment-Bone

--- Content provided by FirstRanker.com ---

? Vascular sinusoids- no adventitial layer
? Patency - volume and pressure of the

marrow tissue

--- Content provided by FirstRanker.com ---

? Marrow is encased in unyielding bone.
? One element can expand-other gets

compressed

--- Content provided by FirstRanker.com ---

NON-TRAUMATIC OSTEONECROSIS

? Intravascular stasis
? Thrombosis
? Extravascular swelling and capillary compression.

--- Content provided by FirstRanker.com ---

Ischaemia- Multifactorial

? Severance of the local blood supply
? Venous stasis and retrograde arteriolar stoppage

--- Content provided by FirstRanker.com ---

? Intravascular thrombosis
? Compression of capillaries and sinusoids by marrow swelling.
Nontraumatic -AVN

? Perthes' disease,

--- Content provided by FirstRanker.com ---

? Caisson disease
? Gaucher's disease

systemic lupus erythematosus

--- Content provided by FirstRanker.com ---

Sickle-cel disease

Dysbaric ischaemia

Thrombocytopenia

--- Content provided by FirstRanker.com ---

Fat embolism

Arteriolar occlusion

--- Content provided by FirstRanker.com ---

Marrow edema Vascular stasis

Sinusoidal compression

Gaucher's disease

--- Content provided by FirstRanker.com ---

Tuberculosis

Cortisone/alcohol

--- Content provided by FirstRanker.com ---

Dysbaric ischaemia


Normal head femur

--- Content provided by FirstRanker.com ---

Pathology and natural history

? Prolonged anoxia ? Osteocyte death
? Gross appearance remains unaltered
? Striking histological changes in the marrow

--- Content provided by FirstRanker.com ---

? Loss of fat cell outlines

? Inflammatory cell infiltration

--- Content provided by FirstRanker.com ---

? Marrow oedema

? Replacement of necrotic marrow- mesenchymal tissue.

--- Content provided by FirstRanker.com ---

Bone repair?

? New blood vessels and osteoblastic proliferation at the interface

between ischaemic and live bone.

--- Content provided by FirstRanker.com ---

? Vascular granulation tissue advances from the surviving trabeculae
? New bone is laid down upon the dead- creeping substitution
? Increase in mineral mass - increased density or `sclerosis'.

--- Content provided by FirstRanker.com ---

Further progress

? Reparative formation proceeds slowly
? Advances 8?10 mm into the necrotic zone.
? Structural failure begins- most heavily stressed part of the necrotic

--- Content provided by FirstRanker.com ---

segment.

? Linear tangential fracture close to the articular surface.

--- Content provided by FirstRanker.com ---

Stage of arthritis

? Articular cartilage retains its thickness and viability for a long time.
? In the final stages- fragmentation collapse of the necrotic bone

--- Content provided by FirstRanker.com ---

? Progressive deformity and destruction of the joint surface.

Clinical features

? The earliest stage of bone death is asymptomatic

--- Content provided by FirstRanker.com ---

? Patient presents with pain - lesion is usually well advanced.
? Pain in or near a joint
? Few complain of a `click' in the joint- due to snapping or catching of a

loose articular fragment.

--- Content provided by FirstRanker.com ---

Stage of arthritis

? Joint becomes stiff and deformed.

--- Content provided by FirstRanker.com ---

? Local tenderness may be present
? Superficial joints- effusion.
? Movements ?may be restricted
? Advanced cases- fixed deformities.

--- Content provided by FirstRanker.com ---

Radiographs

? The early signs of ischaemia -bone marrow and cannot be detected.
? 3 months after the onset of ischaemia- first sign
? Reactive new bone formation at the boundary of the ischaemic area -

--- Content provided by FirstRanker.com ---

sclerosis


Thin tangential fracture line just below the

--- Content provided by FirstRanker.com ---

articular surface ?the `crescent sign'.

Late -collapse and distortion of the articular

--- Content provided by FirstRanker.com ---

surface


MRI Scan

--- Content provided by FirstRanker.com ---

? The most sensitive modality ? marrow changes are discernable
? The size of the necrotic segment-hypo-intense band in the T1,MRI

AVN ?Distal femur

--- Content provided by FirstRanker.com ---

AVN Talus

AVN -Capitulum
Radionuclide scanning

--- Content provided by FirstRanker.com ---

? 99mTcsulphur colloid- taken up in myeloid tissue.
? Useful in traumatic avascular necrosis- large segment of bone is

involved.

--- Content provided by FirstRanker.com ---

? Sickle-cell disease - `cold' area contrasts significantly with the

generally high nuclide uptake due to increased erythroblastic activity.

--- Content provided by FirstRanker.com ---

Staging the lesion

? Ficat and Arlet (1980) introduced the concept of radiographic staging

for osteonecrosis of the hip

--- Content provided by FirstRanker.com ---

? Early (pre-symptomatic) signs- sclerosis, crescent sign.
? Later features- progressive demarcation and collapse of the necrotic

segment in the femoral head.

--- Content provided by FirstRanker.com ---

Stage 1 ? No radiological changes

? Diagnosis was based on measurement of raised intraosseous pressure

--- Content provided by FirstRanker.com ---

? Histological features of bone biopsy
? MRI

Stage II

--- Content provided by FirstRanker.com ---

? The femoral head contour was still normal
? Early signs of reactive change in the subchondral area


Stage 3

--- Content provided by FirstRanker.com ---

? Signs of osteonecrosis with evidence of structural damage and

distortion of the bone outline.

--- Content provided by FirstRanker.com ---

? Collapse of the necrotic segment

Stage 4

? Collapse of the articular surface and signs of secondary OA.

--- Content provided by FirstRanker.com ---

Diagnosis of the underlying disorder

? Episode of trauma- obvious
? Occupation- deep-sea diving or working under compressed air
? Family background of Gaucher's disease or sickle-cell disease.

--- Content provided by FirstRanker.com ---

? High-dosage corticosteroid administration; renal transplantation.
? Low dose use ?quacks, inappropriate use
? Alcohol abuse is often difficult to determine
? SLE- antiphospholipid antibodies may be measured.

--- Content provided by FirstRanker.com ---

EARLY OSTEONECROSIS

? Bone contour is intact- structural failure can be

prevented.

--- Content provided by FirstRanker.com ---

? Some lesions heal spontaneously and with minimal

deformity;

--- Content provided by FirstRanker.com ---

? Non-weightbearing joints

? Superomedial part of the femoral head

? Non- weight bearing surfaces of the femoral condyles and

--- Content provided by FirstRanker.com ---

talus.


Weight bearing joints

--- Content provided by FirstRanker.com ---

? Poor prognosis-l probably end in structural failure
? Simple measures like non weight bearing- reduce loading.
? If the bone contour is still intact,an `unloading' osteotomy
? Help to preserve the anatomy while remodelling proceeds.

--- Content provided by FirstRanker.com ---

? Medullary decompression and bone grafting may have a

place

Stage II- Core decompression B/L

--- Content provided by FirstRanker.com ---

LATE STAGE OSTEONECROSIS

? Destruction of the articular surface may be give rise to pain and

--- Content provided by FirstRanker.com ---

severe loss of function.

? non-operative management, concentrating on pain control,

--- Content provided by FirstRanker.com ---

modification of daily activities and appropriate, splintage of the joint

? Arthrodesis of the joint, e.g. the ankle or wrist
? Total joint replacement- shoulder, hip and knee.
Q1 Which of the following is an inappropriate

--- Content provided by FirstRanker.com ---

diagnosis?

a) Early Sero-Negative Rheumatoid arthritis
b) Avascular necrosis right hip

--- Content provided by FirstRanker.com ---

c) Tubercular arthritis right hip
d) Torn acetabular labrum

Q 2 The most appropriate investigation for

--- Content provided by FirstRanker.com ---

him is?

a) Tc 99 bone scan
b) MRI scan
c) MARS MRI

--- Content provided by FirstRanker.com ---

d) Contrast enhanced CT Scan
Q3 This is classifiable as Ficat-Arlet-

a) Stage 1
b) Stage 2

--- Content provided by FirstRanker.com ---

c) Stage 3
d) Stage 4

Q 4 The most appropriate treatment ?

--- Content provided by FirstRanker.com ---

a) Non operative with follow up MRI at 6 weeks
b) Non weight bearing and analgesics
c) Bed rest, traction and analgesics
d) Core decompression
Q 5 The patient comes after 2 years and has severe pain in his

--- Content provided by FirstRanker.com ---

hip, decreased ROM and a pronounced limp. Radiographs

reveal collapse of the head with decreased joint space

--- Content provided by FirstRanker.com ---

suggestive of secondary OA. The appropriate management is-

a) Arthroscopic debridement and irrigation
b) Osteochondral grafting
c) Bipolar hip arthroplasty

--- Content provided by FirstRanker.com ---

d) Total hip arthroplasty

Conclusion

? AVN is difficult to diagnose early- High degree of suspicion

--- Content provided by FirstRanker.com ---

? Radiographs in early stages are normal- Trust your findings more!
? Best modality for early diagnosis ?MRI
? Salvage can be tried for Stage I,I
? Advanced stages require ? Total hip arthroplasty