19. Dislocation of the femoral head- Mechanism
• Posterior dislocation (85%)
Flexion-adduction medial rotation
• Central dislocation (fract.transv. and columns)
• Anterior dislocation (10%)
Abduction-side rotation ext.
20. Dislocation of the femoral head
• Superior and posterior displacement
• of the head Volume
• Internal rotation of the femur
21. • Sciatic nerve lesion
• Osteonecrosis: time reduction / trauma. +++
(5% < 6 h , 59% > 6 h )
40% of thr post . dislocations
• Osteoarthrosis: oteochondral impaction
femoral head fracture
+ more often in ant. Dislocations
Dislocation of the femoral head: Complications
22. COLUMN FRACTURE
• Anterior column:
Often assiociated with a post.column F
or transversal F
• Posterior column :
Risk of injury to the sciatic nerve!
23.
24. TRANSVERS FRACTURES
Upper portion attached to the sacrum
stable
Inferior ischiopubic portion
unstable
Cleavage plane in the middle of the head
dislocation risk
(2nd point of rupture)
30. Joint Congruence
• The femoral head has to remaine in the
middle of the acetabulum in to plans
In oblic coronal and axial plan
Congruent
Not Congruent