coxa vara

Definition

Chronic, non metabolic bone disorder

Characterised by increased bone resorption, bone formation and remodelling

Epidemiology

Rare < 40

1 – 3 % population over 60

M > F

Aetiology

Unknown

Paramyxovirus implicated

- measles

- RSV

- canine distemper virus

Electron Microscope

Engelmann's Disease

Progressive diaphyseal dysplasia

- marked thickening of cortices of long bones

Present

Young child with gait disturbance and limb pain

Clinical

Bilateral symmetrical diaphyseal sclerosis of long bones

- Affects endosteal & periosteal new bone

- Metaphysis & epiphysis are normal

Skull base sclerotic

- can get blindness and deafness

Definition

Dysproportionate dwarfism

- short limbs and normal trunk

- rhizomelic

DDx

- physeal dysplasia (SED, MED)

Aetiology

FGF Receptor 3 

- point mutation

- decreases endochondral ossification

- normal intramembraneous ossification

- FGFR3 is found in all pre-bone cartilage & in CNS

- FGFR3 inhibits chondrocyte proliferation in the proliferative zone

Definition

Deformity of proximal femur with neck-shaft angle <125°

Characterised by

- coxa vara

- decreased femoral anteversion

- limp / trendelenberg

- stress fractures

- early OA

Classification   

"ACDDC"

Acquired

2° to underlying disorder

- rickets