Osteochondritis and Avascular Necrosis Flashcards
Avascular Necrosis
Ischaemic necrosis of bone
AVN Epidemiology
Mainly adults
AVN Risk Factors
Trauma Fracture Hyperlipidaemia Thrombophilia Sickle Cell Disease Antiphophyloid deficiency in SLE Decompression Sickness(Caisson's Disease) Alcoholism Steroid Use
Impact of alcoholism and steroid use on bone
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
AVN Aetiology
Chronic Alcohol Abuse
- Alcohol metabolism increases NADH:NAD
- Raised NADH contributes to fatty liver disease and AVN
Disruption to blood supply
-Fractures
AVN Common Sites
Femoral head Scaphoid BOne Femoral Condyles Head of humerus Capitellum
AVN Symptoms
Pain
- Constant or when weight bearing
AVN Imaging Appearance
Large wedge-shaped area of discolouration
Trabeculae without osteophytes in lacunae (repair= creeping substitution)
AVN Investigations
MRI
AVN Treatment
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
AVN Complications
Secondary OA
- Patchy sclerosis and subchondral collapse can occur cause irregularity in the articular surface
Osteochondritis
Inflammation of bone and cartilage
Osteochondritis Epidemiology
Children and young adults
- Due to increased physical activity and increased body weight
Osteochondritis Pathogenesis
- Recurrent impact pro traction injuries cause bleeding and oedema in the bone
- This causes capillary decompression
- Bone necrosis occurs
- Compression fragmentation or separation of the bone follows which can cause flattening of a joint or a pothole in the surface
- Pain and progression to arthritis are common
Osteochondritis Common Sites
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
Types of Osteochondritis (2)
Traction Osteochondritis
Osteochondritis Dissecans
Traction Osteochondritis
Occurts at the apophysis (where a tendon attaches)
Traction OC at tibial tubercle
- Osgood Schlatter’s Disease
Traction OC at calcaneus
- Sever’s Disease
Osteochondritis Dissecans
Fragmentation with separation of bone and cartilage within a joint
Osteochondritis Dissecans Common Sites
Lateral parts of medial femoral condyle in knee
Anteromedial tala bone
Superomedial Femoral Head
Humeral Capitellum
osteochondritis Dissecans Symptoms
Pain
Effusions
Locking
Osteochondritis Dissecans Invstigations
X-ray
MRI
Osteochondritis Treatments
Damaged bone replaced with osteotomy
Large or unstable fragments of bone are pinned for repair
Small fragments are. removed arthroscopically
