Avascular Necrosis - finished Flashcards
What is osteonecrosis?
Death of osseous cellular bone. Most commonly primary, idiopathic or spontaneous.
Where is osteonecrosis commonly found?
Usually found as isolated lesions in the femoral capital epiphysis, distal femur, met heads.
What can cause osteonecrosis?
Trauma: as a result of poor circulation to the bone
Drugs: corticosteroids possibly produce fat emboli
Radiation: unknown mechanism
Alcoholism: possibly due to fat emboli and increase marrow fat
Gout: not clear mechanism
What is the clinical presentation of osteonecrosis?
Local or referred pain
Antalgia
Reduced painful ROM
Adjacent muscle atrophy
What are the radiological features of osteonecrosis?
Commonly seen in epiphyseal centres especially the femoral head, humeral head, distal femur, metaphyseal and diaphyseal areas of long bones.
May see:
- epiphyseal infarction
- fragmentation
- mottled trabecular pattern
- sclerosis
- subchondral cysts
- subchondral fractures
What are the 4 phases of osteonecrosis
(in the text book)
- Avascular
- Revascularisation
- Repair
- Deformity
1.
Define Legg Calve Perthes Disease
Avascular necrosis of femoral capital epiphysis before growth plate closure
How long does perthes last?
2-8 years and is usually self limiting
What is the clinical presentation of legg-calve-perthes?
Vague groin pain
Pain to anteromedial knee
Hip abduction and internal rotation causes pain
+ve trendelenberg
+ faber test
What is the normal age for legg calve perthes? (both age brackets and peak)
Ages 3-12
Peak 5-7
What is the aetiology of legg-calve-perthes?
Disturbance of venous drainage or femoral head vasculature vulnerable between 4-7
During life femoral head supplied by epiphyseal vessels from medial circumflex branches of profunda femoris artery, foveal vessels through ligamentum teres, and metaphyseal vessels from bone marrow. At ages 4-6 epiphyseal vessels provide almost all perfusion.
What is the radiological appearance of legg calve perthes?
Hot on bone scan.
Soft tissue swelling
Increased medial joint cavity width:
- accompanying lateral displacement of the femoral head. Usually as a result of effusion or cartilage hyperplasia. (measure between medial femoral head and pelvic teardrop to assess)
Smaller obturator foramen:
- due to antalgic posture (flexion, ER and slight abduction of affected hip)
Reduced femoral head size:
- due to lack of growth because of impaired blood supply
Lucent clefts across epiphysis:
- the most characteristic is a curvilinear, lucent defect paralleling the superior weight-bearing articulating surface, possibly due to nitrogen gas in this subchondral fracture
- esp visible in the frogleg position
Sclerosis:
- Increased density within the involved epiphysis is a manifestation of revascularization, where new bone is being deposited directly over dead trabeculae and is, therefore, a radiographic sign of healing.
Metaphysis widened and shortened:
- femoral neck is frequently widened transversely and decreased in overall length, the most likely cause is appositional bone growth by the periosteum and cessation in longitudinal growth at the physis.
Cysts
- represent displaced uncalcified growth plate cartilage
- often simulate a benign neoplasm.
Widened lucent physis
What are the 4 stages of legg calve perthes?
- Asymmetrical
- Early asymmetric femoral epiphyseal size (smaller on affected side)
- Apparent increased density of the femoral head epiphysis
- Widening of the medial joint space
- Blurring of the physeal plate - Fragmentation
- Fragmentation subchondral lucency (cresent sign)
- Femoral epiphysis fragments
- Femoral head outline is difficult to make out
- Mottled density
- Thickened trabeculae
- Lack of formation NOT destruction - Reparative
- Reparative re-ossificatkon begins
- Shape of the femoral head becomes better defined
- Bone density begins to return - Healed (+ deformity)
- Healed changes depend on the severity of the femoral head may be nearly normal or may demonstrate
- Flattening of the articular surface, esp superiorly
- Widening of the head and neck of the femur
- Large acetabulum
- Coxa magna
- Femoral head = mushroom cap
- Sagging rope sign - intertrochanteric line
- Coxa varus
What are some characteristic radiological signs of legg-calve-perthes?
- Widening of the medial joint space
- Widening of the head and neck of the femur
- Fragmentation subchondral lucency (cresent sign)
- Femoral epiphysis fragments
- Large acetabulum
- Coxa magna
- Femoral head = mushroom cap
- Sagging rope sign - intertrochanteric line
- Coxa varus
Define Freibergs
Avascular necrosis of metatarsal head most commonly 2nd, and occasionally third.
What is the clinical presentation of Freibergs?
Young adolescents, female 5:1 male, usually 13-18 years with pain and tenderness over affected joint. Pain exacerbated by activity. Pain, palpable swelling.
What is the age bracket and gender is usual for freibergs?
female 5:1 male
usually 13-18 years
What are the radiological signs of freibergs?
Articular cortical changes:
- articular margins of the metatarsal head flatten minimally.
Density changes (patchy sclerosis in active phase): - sclerosis and radiolucent foci within the head are usually visible in the active phases.
Joint space widen
Thickened metaphysis and diaphysis of involved bone, with healing
See enlarged met head with normal density returning, but joint space may be narrowed with subsequent DJD.
Define Kienbocks
Avascular necrosis of the carpal lunate occasionally bilateral
What is the aetiology of Kienbocks
There is probably no single cause of Kienbock’s. Skeletal variations associated with this disease include a shorter length of the ulna, one of the forearm bones, and also the shape of the lunate bone itself. Trauma, either single or repeated episodes, may be a factor. Commonly in people who have medical conditions that affect blood supply, and it is also associated with diseases like lupus, sickle cell anemia, and cerebral palsy
What is the clinical presentation of Kienbocks?
male 9:1 female.
Age group 20-40.
Local and radiating wrist pain, swelling, gradually worsening disability, may lead to severe pain.
What are the radiographical features of Kienbocks?
Bone scan or MRI shows lesion several months before plain X-ray.
Diffuse osteoporosis of adjacent bones
Cortical changes (irregular, flattened or collapsed)
Decreased lunate size
Density initially is increased with it later becoming patchy sclerosis.
After resolution, separation of the scaphoid and lunate .
What view is best to see Kienbocks?
Lateral
Define Kohlers
Possible ischaemic necrosis (vascular deficiency), or may represent a normal growth variant in some cases, of the tarsal navicular.
What is the clinical presentation of kohlers?
Predominantly males around 5 years old.
Local pain, swelling, tenderness and decreased motion.
What are the radiological features of Kohlers?
Patchy or homogenous sclerosis of the navicular
Collapse and fragmentation
Joint spaces preserved.
Bones scan helps differentiate between growth variation frown ischaemic necrosis
Define Osgood-Schlatters Disease
Tendonitis caused by trauma or repetitive microtrauma. May involve partial displacement of patella tendon. Self-limiting but painful and disabling.
What is the clinical presentation of Osgood-Schlatters
Affects adolescents 11-15 with male predilection
Occurs at the tib tub where the tendon inserts
Patient may have an antecedent history
Local pain and tenderness with soft tissue swelling
What is the aetiology of Osgood- Schlatters?
Inflammation at distal patella insertion.
Increases cellularity and vascularity.
Produces oedema of chronic inflammation.
Cartilage and/or bone may be displaced.
Heterotropic new bone forms in inflamed patella ligament.
What is are the radiological features of Osgood-Schlatters?
Soft tissue swelling and oedema
Thickened patella ligament.
Bones appear with irregular isolated ossicles toward anterior margin of tuberosity.
Possible chondro-osseous avulsion.
Define Scheuermanns
Traumatic growth arrest and Schmorl’s nodes (endplate fractures) during adolescent growth.
What is the clinical presentation of Scheuermanns?
Middle and lower thoracic vertebrae, with patients ages usually 13-17. As much as 8% of population affected.
What is the aetiology of scheuermanns?
Mechanism not clear; several suggested:
- secondary ring avascular necrosis
- low grade infection
- deformity secondary to disc extrusion
- hereditary
- malnutrition or vitamin deficiency
- endocrine
- muscular imbalance
- osteoporosis.
What are the diagnostic criteria of Scheuermanns?
A kyphosis leading to at least 3 contiguous segments with wedging of 5 degrees or more of each participating vertebral body
What are the radiological features of Scheuermanns?
Vertebral body wedging:
- trapezoidal shaped vertebrae resulting from a manifestation of inhibited growth, particularly anteriorly.
Irregular end plates:
- They will be demarcated by a sclerotic margin, which is characterised by schmorl’s node herniation
- Predominantly located in the anterior 2/3 of the VB and are usually more severe from the apical segment.
Ring epiphysis abnormalities:
- A fragmented, irregular pattern may be visible
Decreased IVD height:
- More marked loss towards anterior aspect of the disc
Define Severs. Who does it usually occur in?
Overuse of bone and tendons of heel. Leads to osteonecrosis.
More common in children who over pronate.
Self-recovering 2-8 weeks
What age does Severs usually occur in?
Predominantly males 9-11
What is the clinical presentation of Severs?
Local pain, swelling, tenderness and decreased motion.
What are the radiological features of Severs?
Patchy or homogenous sclerosis of the calcaneus
