Osteochondritis and Avascular Necrosis

Question 1

Avascular Necrosis

Answer 1

Ischaemic necrosis of bone

Question 2

AVN Epidemiology

Answer 2

Mainly adults

Question 3

AVN Risk Factors

Answer 3

Trauma
Fracture
Hyperlipidaemia
Thrombophilia
Sickle Cell Disease
Antiphophyloid deficiency in SLE
Decompression Sickness(Caisson's Disease) 
Alcoholism
Steroid Use

Question 4

Impact of alcoholism and steroid use on bone

Answer 4

Alter fat metabolism.
Cause mobilisation of fat in the circulation.
Capillary system struggles to maintain normal flow.
Promotes coagulation in prone areas of blood.
Increased fat content also compresses venous outflow causing stasis and ischaemia

Question 5

AVN Aetiology

Answer 5

Chronic Alcohol Abuse

• Alcohol metabolism increases NADH:NAD
• Raised NADH contributes to fatty liver disease and AVN

Disruption to blood supply
-Fractures

Question 6

AVN Common Sites

Answer 6

Femoral head
Scaphoid BOne
Femoral Condyles
Head of humerus
Capitellum

Question 7

AVN Symptoms

Answer 7

Pain

- Constant or when weight bearing

Question 8

AVN Imaging Appearance

Answer 8

Large wedge-shaped area of discolouration

Trabeculae without osteophytes in lacunae (repair= creeping substitution)

Question 9

AVN Investigations

Answer 9

MRI

Question 10

AVN Treatment

Answer 10

If articular surface has NOT collapsed
- Drilling under fluoroscopy to decompress bone

If articular surface has collapsed

• Joint replacement
• Fusion is considered in wrist or ankle bones

Question 11

AVN Complications

Answer 11

Secondary OA

- Patchy sclerosis and subchondral collapse can occur cause irregularity in the articular surface

Question 12

Osteochondritis

Answer 12

Inflammation of bone and cartilage

Question 13

Osteochondritis Epidemiology

Answer 13

Children and young adults

- Due to increased physical activity and increased body weight

Question 14

Osteochondritis Pathogenesis

Answer 14

1. Recurrent impact pro traction injuries cause bleeding and oedema in the bone
2. This causes capillary decompression
3. Bone necrosis occurs
4. Compression fragmentation or separation of the bone follows which can cause flattening of a joint or a pothole in the surface
5. Pain and progression to arthritis are common

Question 15

Osteochondritis Common Sites

Answer 15

2nd Metatarsal Head
- Freiburg’s Disease

navicular Bone
- Kohler’s Disease

Lunate of carpus
- Kienbock’s DIsease

Capitellum of Elbow
- Panner’s Disease

Vertebral Compression
- Scheuermann’s Disease

Perthes Disease

Question 16

Types of Osteochondritis (2)

Answer 16

Traction Osteochondritis

Osteochondritis Dissecans

Question 17

Traction Osteochondritis

Answer 17

Occurts at the apophysis (where a tendon attaches)

Traction OC at tibial tubercle
- Osgood Schlatter’s Disease

Traction OC at calcaneus
- Sever’s Disease

Question 18

Osteochondritis Dissecans

Answer 18

Fragmentation with separation of bone and cartilage within a joint

Question 19

Osteochondritis Dissecans Common Sites

Answer 19

Lateral parts of medial femoral condyle in knee

Anteromedial tala bone

Superomedial Femoral Head

Humeral Capitellum

Question 20

osteochondritis Dissecans Symptoms

Answer 20

Pain
Effusions
Locking

Question 21

Osteochondritis Dissecans Invstigations

Answer 21

X-ray

MRI

Question 22

Osteochondritis Treatments

Answer 22

Damaged bone replaced with osteotomy

Large or unstable fragments of bone are pinned for repair

Small fragments are. removed arthroscopically