Diaphyseal Aclasis / Multiple Osteochondromas
Heritable skeletal dysplasia
AD with variable penetrance (96%)
Incidence of malignant transformation much higher
- 10% overall
- 1 % / year
Chondrosarcoma (CS) > Osteosarcoma (OS)
Virchow's Triad
1. Venous stasis
2. Hypercoagulability
3. Endothelial damage
Starts as platelet nidus at valves
- thrombogenic materials elaborated by platelets
- leads to development of fibrin thrombus
- thrombus grows
Thrombus may
- detach as embolus
- be completely dissolved / recanalise
- organise with valve incompetence
Lateral curvature of the spine with vertebral rotation
- defined as > 10o coronal plane deformity
- occurs at or near the onset of puberty
- no cause is established
Triplanar
- coronal / scoliosis
Dysproportionate dwarfism
- short limbs and normal trunk
- rhizomelic
DDx
- physeal dysplasia (SED, MED)
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
Developmental dysplasia of the hip
- the femoral head does not have the normal relationship with the acetabulum
- child with subluxable, reducible or irreducible hip
- may not be present at birth (hence not called CDH)
Instability
- ability to dislocate or reduce femoral head into or out of acetabulum
Dislocated
- complete loss of contact